¹University of Central Florida/HCA Healthcare Consortium, Tallahassee, FL, USA
²Dermatology Associates of Tallahassee, Tallahassee, FL, USA
³Florida State University College of Medicine, Tallahassee, FL, USA
^* Co-first authors

Conflict of interest: None.
Funding sources: None.
Disclaimer: This research was supported in whole or in part by HCA Healthcare and/or an HCA Healthcare affiliated entity. The views expressed in this publication represent those of the authors and do not necessarily represent the official views of HCA Healthcare or any of its affiliated entities.

Abstract:
Seborrheic dermatitis (SD) is a chronic inflammatory skin disorder most commonly affecting areas rich in sebaceous glands, such as the scalp, face, axilla, and groin. Several factors can precipitate SD development, such as colonization of Malassezia, sebocyte activity, impaired immunity, and environmental influences. Topical antifungals, corticosteroids, and calcineurin inhibitors are the current mainstay treatment of SD. Recent clinical trials have validated the efficacy of non-steroidal roflumilast 0.3% foam for the treatment of SD. In this review, we analyze the safety and efficacy profile of roflumilast 0.3% foam.

Keywords: seborrheic dermatitis, treatment, roflumilast, PDE-4 inhibitor

Introduction

Seborrheic dermatitis (SD) is a chronic inflammatory skin disorder most commonly affecting areas rich in sebaceous glands, such as the scalp, face, axilla, and groin.¹ While clinical presentations may differ, typical findings include erythematous, pruritic plaques and patches with a yellow, greasy appearance.^1,2 This condition can significantly impact quality of life due to activity limiting symptoms and emotional distress exacerbated by cosmetic ramifications.³ SD affects approximately 5% of the global population, whereas its non-inflammatory counterpart, dandruff, likely impacts closer to 50%.⁴ Despite such high prevalence, the pathogenesis and exact mechanisms via which these yeasts cause inflammation have yet to be fully elucidated.

Malassezia is a part of the human microbiome, interacting with the innate and acquired skin immune system. Innate immunity plays a critical role in initiating the initial immune response against Malassezia.⁵ Sensitization to Malassezia can cause a type I hypersensitivity reaction leading to redness, itching, and scaling.⁶ Further studies point towards Malassezia causing an irritant, non-immunogenic stimulation of the immune system, leading to complement activation and a localized increase in NK1+ and CD16+ cells.^7,8

Currently, there are many mainstay treatments for SD. Due to the underlying mechanism of Malassezia proliferation, most commonly topical antifungals are used for long-term treatment and topical corticosteroids and calcineurin inhibitors for short-term treatment (Table 1).¹ Due to the chronicity of SD, ongoing maintenance therapy is often necessary to achieve low recurrence rates of visible signs of the condition, as well as alleviate associating symptoms, such as pruritus.

Table 1

Phosphodiesterase-4 (PDE-4) inhibitors, including roflumilast, represent a significant advancement in the treatment of SD and other inflammatory conditions. These drugs work by inhibiting the PDE-4 enzyme, which plays a role in modulating inflammatory responses by breaking down cyclic adenosine monophosphate (cAMP).^9,10 Elevated levels of cAMP result in reduced inflammation, making PDE-4 inhibitors effective in managing various ongoing inflammatory disorders such as chronic obstructive pulmonary disease (COPD) and asthma.¹⁰ In dermatology, PDE-4 inhibitors have received regulatory approval in the US and Canada for plaque psoriasis, psoriatic arthritis, atopic dermatitis and, most recently, SD. They have shown promise in off-label treatment of a myriad of other inflammatory skin conditions. Apremilast is an oral PDE-4 inhibitor FDA-approved for psoriasis and psoriatic arthritis in patients ≥6 years of age. Crisaborole is a topical PDE-4 inhibitor, currently FDA-approved for atopic dermatitis in patients ≥3 months of age. Roflumilast has also demonstrated safety and efficacy in managing chronic inflammatory skin conditions, with the regulatory approval status in the US and Canada summarized in Table 2. Compared to currently available PDE-4 inhibitors, apremilast and crisaborole, used to treat skin disease, roflumilast has demonstrated greater selectivity and potency.^9,10

Table 2

Herein, the review will focus on the treatment of SD with a particular emphasis on roflumilast 0.3% foam.

Mechanism of Action

Roflumilast and its active metabolite (roflumilast N-oxide) are inhibitors of PDE-4.⁹ Inhibition of PDE-4 leads to an increase in cAMP and subsequent decrease in pro-inflammatory mediators such as interleukin (IL)-17, IL-23, tumor necrosis factor alpha, and interferon gamma.¹⁰

Clinical Trials

Phase 2¹¹

The Phase 2a study design was a parallel-group, double-blind, vehicle-controlled randomized clinical trial of once-daily roflumilast 0.3% foam. A total of 226 participants aged 18 or older were enrolled in the 8-week trial conducted at 24 sites in the US and Canada with a clinical diagnosis of SD for a 3-month long duration and affecting less than 20% body surface area, including the scalp, face, trunk, and/or intertriginous areas. Roflumilast 0.3% foam demonstrated a statistically significant increase in treatment success, with 104 participants (73.8%) achieving an Investigator Global Assessment (IGA) score of 0 or 1, compared to its vehicle. At week 8, 50 individuals (35.5%) attained an IGA score indicating clearance, while 54 patients (38.3%) achieved an IGA score signifying almost clear skin. In comparison, the vehicle group exhibited lower rates of improvement, with only 10 patients (15.2%) reaching clearance and 17 patients (25.8%) achieving almost clear status. Roflumilast patients exhibited significantly higher rates of erythema success, defined as an overall erythema score of 0 (clear) or 1 (almost clear) plus a 2-grade improvement from baseline, compared to those treated with the vehicle. At weeks 2, 4, and 8, respective absolute differences were 16.6% (95% Confidence Interval (CI): 6.4%-24.8%), 25.2% (95% CI: 13.1%-34.9%), and 23.5% (95% CI: 9.6%-35.0%). Similar results were noted for scaling success, defined as overall scaling score of 0 (clear) or 1 (almost clear) plus a 2-grade improvement from baseline. Statistically significant differences at weeks 2, 4, and 8: absolute differences were 11.8% (95% CI: -0.3% to 21.8%), 20.4% (95% CI: 6.8%-31.8%), and 28.8% (95% CI: 14.4%-41.0%), respectively. Overall, roflumilast 0.3% foam exhibited good tolerability, with a low occurrence of adverse events.

Phase 3¹²

The Phase 3 trial design was a parallel-group, double-blinded, vehicle-controlled, multicenter (50 centers) study with participants aged ≥9 years who were clinically diagnosed with SD affecting up to 20% body surface area, including the scalp, face, trunk, and/or intertriginous areas. 457 patients were randomly assigned in a 2:1 ratio to roflumilast (n = 304) or vehicle (n = 153). The primary endpoint was an IGA score of 0 (clear) or 1 (almost clear) and a ≥2-point improvement from baseline by week 8. The secondary endpoints included IGA success by weeks 2 and 4 and a ≥4-point improvement on the Worst Itch Numeric Rating Scale score (WI-NRS).

During this 8-week trial, a statistically significant amount of roflumilast treated patients (79.5%) achieved IGA success compared with vehicle (58.0%; P < 0.001). Roflumilast also demonstrated success at weeks 2 and 4, with percentages of IGA success of 43.0% versus 25.7% (P < 0.001) and 73.1% versus 47.1% (P < 0.001). At week 8, a higher percentage of patients treated with roflumilast (62.8%) achieved WI-NRS success compared to those treated with the vehicle (40.6%: P < 0.001), with improvement observed within 48 hours after the first application, respectively (Table 3).

Table 3

Safety and Tolerability

Overall, roflumilast 0.3% foam was well tolerated, and had similar rates of adverse events (AE) as the vehicle. During all phases of the study, there were no treatment emergent adverse events (TEAEs) reported as a direct result of roflumilast 0.3% foam treatment.^11,12 The most prevalent adverse reactions, observed in ≥1% of subjects across both Phase 2 and Phase 3 study groups included nasopharyngitis (1.5%), nausea (1.3%), and headache (1.1%).^11,12 Less frequent AEs included application site pruritus, application site pain, and diarrhea.^11,12 There were no significant differences between groups noted in clinical laboratory assessments. Vital signs, body weight, and body mass index indicated no clinically meaningful variations.¹² Moreover, evaluations for depression, suicidal ideation, and behavior revealed no safety concerns.¹²

Contraindications

Contraindications include individuals with a known hypersensitivity to roflumilast or any of the components in the formulation, as this can lead to severe allergic reactions. Additionally, patients with moderate to severe liver impairment (Child-Pugh B or C) should not use roflumilast, as it may exacerbate liver dysfunction.¹³ The coadministration of roflumilast with systemic CYP3A4 inhibitors or dual inhibitors that inhibit both CYP3A4 and CYP1A2 may increase roflumilast systemic exposure and result in increased adverse reactions.¹³ It should be noted that no formal drug-drug interaction studies were done with topical roflumilast and these recommendations are based on oral roflumilast, which has a much greater bioavailability.

Regulatory Approval

The roflumilast 0.3% foam formulation was approved by the US FDA in December of 2023 and Health Canada in October 2024 for the treatment of SD in individuals aged ≥9 years.¹⁴ The medication is to be applied once daily to the affected areas, with the duration determined by the healthcare provider. One pressurized can of roflumilast 0.3% foam (60 g) contains 3 mg roflumilast per 1 g.

Discussion

Current first-line therapies for SD typically include topical antifungals and topical steroids (Table 1). These treatments are often readily available and affordable, leading to their widespread use. While these are effective in many cases, some individuals require a combination of multiple topicals for control which contributes to patient non-compliance due to complex treatment regimens.⁴ Moreover, these treatments may be ineffective in some individuals and can be associated with poor tolerability due to various AEs such as local skin reactions, burning, pruritus, and blistering.⁴

Roflumilast 0.3% foam provides an additional non-steroidal anti-inflammatory treatment option in those who have failed first-line therapies or prefer a once daily treatment regimen. It marks the first regulatory approved medication for SD with a novel mechanism of action in over two decades. This foam is uniquely formulated in a water-based emollient formula without skin irritating fragrances or alcohols such as, propylene glycol, polyethylene glycol, isopropyl alcohol, or ethanol.¹⁴ It is reported to be the first-in-class drug formulated with a novel emulsifier that lacks ceramide stripping properties. The hydrating features of the vehicle itself may add to its therapeutic effect. Moreover, the non-irritating, non-steroidal formula enables use anywhere on the body, including the eyelids and genitalia. The non-greasy foam formulation lends itself to use on hairy scalps.

Roflumilast may improve adherence and tolerance due to its once daily application, potent formulation, and minimal AEs. Its greater selectivity for PDE-4 than apremilast and crisaborole, likely contributes to its low side effect profile. Few patients reported stinging, burning, application site reactions, or application site pain with roflumilast.¹² Data from key trials reported IGA success, defined as IGA of 0 (clear) or 1 (almost clear) plus ≥2-point improvement from baseline in 80% of participants, with some reaching IGA success as early as weeks 2 and 4.¹² Pruritus, measured via the WI-NRS, improved as early as 48 hours after application. These results are in-line with other first-line therapies (Table 3).

With the continual push for more effective and safer therapies, roflumilast appears to be a useful agent added to the SD armamentarium.

Conclusion

Due to its minimal AEs and favorable tolerability, the novel roflumilast 0.3% foam offers a safe treatment for the erythema, scaling, and pruritus caused by SD. Its once daily application and potent formulation provides a convenient and effective treatment for SD. This treatment highlights the importance of continued advancement in the development of innovative therapies for SD as it is essential to improve outcomes and enhance the quality of life for individuals affected by this condition.

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Abstract

Background: Atopic dermatitis (AD) is a heterogeneous disease characterised by epidermal barrier dysfunction and immune dysregulation. It commonly presents with pruritus and eczematous lesions that significantly impact quality of life. Abrocitinib is a JAK inhibitor approved for treatment of refractory, moderate-to-severe AD in patients 12 years and older.

Objectives: This real-world case series intends to illustrate a variety of moderate-to-severe AD patient cases to help guide discussions around abrocitinib and describe its treatment strategies used by experts in the field.

Methods: Expert panel members were recruited from across Canada to discuss varying clinical AD phenotypes seen in their clinic. Guided by literature, the panel shared their opinions and insights to provide a holistic view of the overarching question, “Which patients are good abrocitinib candidates?”

Results: The panel reported on ten real-world patient cases that detailed the use of abrocitinib in biologic naïve patients, refractory AD patients, complex medical patients, and those with differing treatment goals. Cases aim to demonstrate the broad use of abrocitinib in patients with AD, offering a learning point with each real-world case.

Conclusions: Each presented real-world case reflects the panel’s clinical experience. Panel members concluded that abrocitinib is a fast-acting, safe, and efficacious therapy for a wide variety of AD patients with differing disease severities and comorbidities. Treatment with abrocitinib may cause transient nausea that frequently resolves by taking it with food. Overall, patients are highly satisfied with the treatment.

Keywords: atopic dermatitis, real-world cases, JAK inhibitor, abrocitinib

Disclosures and Acknowledgment: The authors conducted the real-world series, supported by an educational grant from Pfizer Canada. The authors acknowledge and thank Sophie Guénin, MSc, for her assistance in preparing this manuscript.

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Introduction

Atopic dermatitis (AD) is a heterogeneous, chronic inflammatory skin disease characterized by epidermal barrier breakdown, immune dysregulation, and significantly reduced quality of life (QoL).¹ Approximately 3.5% of the total Canadian population and 25.4% of the pediatric Canadian population is affected with AD.^1,2 This relapsing condition may present as dry, erythematous, sensitive skin or pruritic, excoriated, eczematous, and painful patches with weeping erosions and prurigo nodules.¹ About one-third of AD patients are affected by atopic comorbidities such as asthma, food allergy, and hay fever.³

Patients with AD report impaired quality of life that limits their daily lives and social interactions.³ Pruritus is reported as the most burdensome symptom of AD, with 95% of patients reporting itch as the most important indicator of treatment response.⁴ Other burdensome symptoms included excessive dryness, scaling, inflamed skin, skin pain, and sleep disturbance.⁴ Impaired barrier function in AD is largely attributed to filaggrin dysfunction.⁵ Meanwhile, immune dysregulation in AD largely stems from T-helper (Th)2 cell cytokines, interleukin (IL)-4 and IL-13, in its acute phase and Th1 skewing in chronic disease.⁶ IL-22 and IL-17-producing T cells have also been implicated in the pathogenesis of AD.⁶

Systemic Treatment for Moderate-to-Severe AD

The consensus-based European guidelines for the treatment of AD recommend proactive therapy with topical calcineurin inhibitor (TCI) or topical glucocorticosteroids (TCS) for moderate AD along with narrow band (nb) UVB phototherapy, psychosomatic counseling, and climate therapy.⁶ For severe AD, the guidelines recommend hospitalization in specific cases, systemic immunosuppression with cyclosporine, short-course oral glucocorticosteroids, methotrexate, azathioprine, or mycophenolate mofetil.⁷ Biologic monoclonal antibody therapies such as dupilumab are also recommended for severe AD patients.⁷

Dupilumab is an anti-IL-4-receptor α monoclonal antibody that inhibits the signaling of both IL-4 and IL-13.⁶ Since the guidelines were published in 2018, an additional monoclonal antibody therapy, tralokinumab, an IL-13 inhibitor, has been approved for AD treatment in Canada, as well as two janus kinase inhibitors (JAK) inhibitors (JAKi): abrocitinib and upadacitinib.⁶

Newer topicals such as the topical PDE4 inhibitor, crisaborole, has also been recently introduced for AD treatment, and ruxolitinib, a topical JAK inhibitor, not yet available in Canada.^6,7

Abrocitinib & JAK Inhibitors (JAKis)

JAKis are a new class of systemic treatments for AD that function by blocking downstream cytokine inflammatory signaling.⁶ Abrocitinib and upadacitinib are once daily, oral JAK1 inhibitors that block IL-4 and IL-13, cytokines involved in the pathogenesis of AD, downstream.^8,9 Abrocitinib is available in three doses: 50 mg, 100 mg, and 200 mg, and is approved for moderate-to-severe AD patients aged 12 and older.⁹ In pivotal trials JADE MONO-1 and JADE-MONO-2, abrocitinib demonstrated significant pruritus reduction within two weeks.^10,11 In a phase 3 comparative clinical trial, JADE-COMPARE, abrocitinib 200 mg demonstrated greater IGA response and itch response at endpoint than dupilumab.¹² As with all JAK inhibitors, abrocitinib has inherited a black box warning for thrombosis, major adverse cardiovascular events (MACE), and malignancy. Despite this, clinical trial safety analysis at 48 weeks of both the 100 mg and 200 mg abrocitinib dosage groups showed only 0% to 0.3% incidence of the following: nonmelanoma skin cancer (NMSC), malignancy, MACE, or VTEs.¹³

Upadacitinib is approved for the treatment of AD, rheumatoid arthritis, psoriatic arthritis, ulcerative colitis, Crohn’s disease, ankylosing spondylitis, and non-radiographic axial spondylarthritis.⁹ In refractory moderate-to-severe AD, upadacitinib is approved in Canada for ages 12 and up with two dosing options: 15 mg and 30 mg; recommendations suggest initiating treatment at 15 mg prior to titrating up to 30 mg.¹⁴

As more treatments become available, it will be important for clinicians to partner with patients in a treat-to-target (TTT) paradigm to identify the optimal AD treatment for each patient.¹⁵

Methods

Aim of the Project

This real-world case series illustrates a variety of patients with moderate-to-severe AD treated with abrocitinib. The cases outline the TTT paradigm and demonstrate patient-provider partnerships that highlight patient priorities and ideal treatment options. Expert panelists’ thought processes, reasoning, and rationales are detailed in the following patient cases to serve as a guide for licensed providers who treat patients with AD.

Steps in the Process

The project was conducted in the following five steps: 1) project definition and expert panel selection 2) data collection and preparation of patient cases, 3) patient case discussion and selection for publication 4) literature review to support selected cases 5) drafting, review, and finalization of the manuscript.

Role of the Panel

The panel consisted of 10 dermatologists practicing in Canada who commonly care for patients with AD. Panelists were chosen from 3 provinces in Canada to capture geographical and provincial differences in dermatological practice. During the Dermatology Update conference on April 30^th, 2023, in Vancouver, panelists met to report on and discuss clinical cases of AD patients who were suitable candidates for abrocitinib treatment.

The panel used the following template to gather insight through a case-based approach:

Panelists were asked to select two patient cases from their clinical practice to share and discuss. In the second half of the meeting, panelists examined and collaborated to select ten real-world cases for inclusion in the publication. Panel members agreed that real-world cases should focus on common AD scenarios encountered in the clinic. The publication was prepared and reviewed by the panel.

Experience Gathering and Atopic Dermatitis Outcome Measures

Suggested information and outcome measures to present included patient demographics, concomitant medications, comorbidities and Investigators’ Global Assessment (IGA) score, Eczema Area and Severity Index (EASI), Peak Pruritus Numerical Rating Scale (PP-NRS), and patient-reported Dermatology Life Quality Index (DLQI) at weeks 0, 2, and 4 (+/- 5 days) of abrocitinib treatment (Appendix 1). Panelists were also requested to report patient compliance, treatment satisfaction, and any adverse events experienced.

Results

Selected Real-World Cases

The panel selected ten cases to demonstrate the real-world use of abrocitinib in a diverse group of patients with varying skin concerns, past treatment failures, severity, and comorbidities. The findings reflect real-world clinical use of oral abrocitinib and patient treatment outcomes.

Case 1: The recalcitrant, severe AD patient with intense pruritus

A 31-year-old Caucasian, Fitzpatrick Skin Type (FST) 1, female struggling with severe, recalcitrant AD for the past 18 years presented with reported worsening anxiety, avoidance of social activities, and sleep interruption due to debilitating pruritus. Intense pruritus led to diffuse excoriations and multiple skin infections. Her EASI was 22, and DLQI 20. Over the years, the patient had tried TCS, TCI, crisaborole, nbUVB phototherapy, and systemic therapies: prednisone, methotrexate, and intramuscular triamcinolone injection. She had developed striae on her abdomen and arms from frequent TCS use and continued to suffer from intractable itch. The patient started dupilumab but discontinued it after three months due to repeated flu-like symptoms and nasopharyngitis. Having failed first, second-, and third-line therapies for AD, the patient was started on abrocitinib, 200 mg daily. The rationale for beginning abrocitinib at the higher dose was the failure of previous treatment and the patient’s primary complaint of incessant itch. Within eight weeks, she saw rapid improvement; her EASI was 8 and DLQI 4. At week 16, her EASI was 2 and DLQI 0. When asked about her experience, the patient reported that abrocitinib had “life-changing” effects after only one month of treatment. No adverse events occurred, and the patient was reduced to 100 mg abrocitinib daily without exacerbation.

Learning point: Abrocitinib is a fast-acting, effective, and safe treatment option for patients with longstanding, recalcitrant AD. It may be an option for patients who have failed many prior therapies. Abrocitinib therapy can improve patients’ QoL and reduce the need for TCS and other adjunct therapies, thereby sparing patients from the undesirable adverse effects of these treatments.

Case 2. The biologic-naïve patient

Since early childhood, a 55-year-old Caucasian (FST1) salesman with hypertension, hypercholesterolemia, and prediabetes had suffered from severe AD that affected extensive parts of his head, neck, trunk, and extremities. Since starting amlodipine and rosuvastatin for his comorbid conditions, the patient reported worsening xerosis and diffuse erythema.

While biologic naïve, he had previously tried various moisturizers, TCS, TCI, phototherapy, and oral antihistamines with only modest benefit. Despite the multimodal treatment approach, the patient continued to have frequent visits to the Emergency for infections and exacerbations. His condition greatly impacted his work and social interactions as well as his psychological and sexual health. Given his frequent business travel, busy family life, and needle aversion, the patient expressed interest in a convenient, effective treatment that would improve his worsening xerosis and eliminate the requirement for additional therapies. For these reasons, the patient was started on 100 mg abrocitinib. Within two weeks, the patient’s IGA score reduced from 3 to 2, EASI score from 4 to 2 and PP-NRS score from 8 to 3. Two weeks later, the patient saw continued improvement with an IGA score of 1, EASI score of 1, and PP-NRS score of 2. Rapid reduction in itch made the patient extremely satisfied with abrocitinib monotherapy. He did not experience any adverse events and was “thrilled” with his outcome. The patient remains on abrocitinib 100 mg with the option to increase to 200 mg, if necessary.

Learning point: JAKi is an option for biologic-naïve patients for whom self-injection does not correspond to their lifestyle. Patients who travel frequently or lead busy lifestyles may have difficulty transporting subcutaneous injections that must be stored in cool temperatures or having the proper setting to self-inject. Further, some patients are needle-phobic and would prefer an effective, oral treatment option.

Case 3. The patient with post-inflammatory hyperpigmentation

A 29-year-old Southeast Asian (FST4) female presented with sensitive skin, longstanding AD and significant post-inflammatory hyperpigmentation (PIH) around her eyes and on her arms. She had been treated with multiple courses of prednisone with a good response but would predictably flare 2-4 weeks after steroid discontinuation. Having suffered from AD since infancy, she reported the post-inflammatory hyperpigmentation from AD as her most bothersome symptom. Previous treatments included TCS, TCI, and crisaborole. She saw a slight improvement in her skin and pruritus with topical therapy in conjunction with oral antihistamines. Despite mild improvement, she was still desperate for a long-term, effective solution. Her primary care physician had recently made her aware of abrocitinib and encouraged her to seek evaluation by a dermatologist. As a young, single female without any plans for pregnancy in the near future, the patient was a good candidate for abrocitinib and was started on abrocitinib 100 mg. Her IGA was 3 at baseline, EASI score was 4, and PP-NRS score was 8. By week 4, her IGA, EASI, and PP-NRS scores were all 1, and she felt happy and hopeful that PIH marks would continue to fade with time. No compliance issues or adverse reactions were reported.

Learning point: Patients with skin of colour are at increased risk for PIH. Consistent AD treatment with abrocitinib and control of AD, results in PIH improvement and improved mood and QoL. It also reduces inappropriate, long-term use of oral corticosteroids. In females of childbearing age, it is also important to inquire about pregnancy and/or contraceptive use. Pregnancy is a contraindication for abrocitinib use. It should be recognized that contraceptive use may lead to low risk of VTE. Family planning should be discussed with all patients of childbearing potential who are contemplating treatment with abrocitinib.

Case 4. The atopic patient with barriers to treatment access

A 22-year-old (FST2) male with lifelong AD and comorbid atopic diseases (hay fever, asthma, and urticaria) presented with worsening pruritus. Physical exam revealed symmetric, generalized excoriated red, scaly patches with significant lichenification on his bilateral extremities, face, scalp, and back. Working as a dishwasher, the patient reported wearing gloves most of the day to protect his skin from irritating soaps or dryness. Despite his precautions, his skin began impacting his ability to work. He reported skin burning, discomfort, unbearable itch, and skin pain, which frequently disrupted his sleep. At presentation, while on methotrexate, his EASI was 23, IGA score 4, and DLQI 18, with 31% of his body surface area (BSA) affected by AD (Figure 1A [back – face]). Throughout his lifetime, the patient had tried lifestyle modifications such as fragrance-free, hypoallergenic detergent, gentle cleansers, moisturizer application every 2 hours as well as TCS, TCI, calcipotriol gels, oral antihistamines, systemic corticosteroids, and 1-year of methotrexate. Given the severity of the patient’s AD and worsening QoL, the plan was to begin biologic monoclonal antibody therapy. Unfortunately, the patient could not gain access to dupilumab or tralokinumab through his insurance, compassionate drug program, or patient assistance programs. Fortunately, the patient was able to access 100 mg abrocitinib and was thus started on this oral therapy in lieu of biologic therapy. The 100 mg dose was chosen since the patient and his mother were risk-averse and wished to try the 100 mg dose first, increasing to 200 mg only if the 100 mg dose was not sufficient. Two weeks prior to starting abrocitinib, the patient was given his first shingles vaccine. At his 11-week follow-up visit, the patient reported no skin pain and minimal itch with only slight residual erythema on his face (EASI 1.1, IGA 1) (Figure 1B [face – back]). He reported that he could sleep through the night and was able to stop using topical therapies and antihistamines. Of note, the patient experienced mild initial nausea and abdominal pain that abated within the first few weeks of treatment. He had his second shingles vaccine after commencing abrocinitib treatment.

Learning point: Abrocitinib is readily accessible to some patients who are unable to gain coverage for monoclonal antibody therapies such as dupilumab and tralokinumab. While addressing itch, abrocitinib also effectively targets skin pain. It is important to consider shingles vaccination prior to abrocitinib start. The second dose of the vaccine can be given 1-6 months later.¹⁶ Nausea may also be an important adverse effect to discuss with patients. Nausea is frequently transient and can be improved by taking abrocitinib with food.

Figure 1: 22-year-old male with severe AD
(Photos courtesy of Lyn Guenther MD, FRCPC)

Case 5. The complex medical patient with persistent AD-related pruritus

The retired aerospace worker, two-time widower, and former smoker the 63-year-old man, has atopic triad and comorbid anxiety, depression, hyperlipidemia, hypertension, and a history of stroke. He presented with persistent AD, severe pruritus, and atopic keratoconjunctivitis (AKC). His concomitant medications included: citalopram, atorvastatin, ezetimibe, perindopril, and clopidogrel. Despite his other conditions, the patient was most concerned with his pruritus as it had prevented him from sleeping, exercising, socializing, dating, and working. He had only slept through the night three times in the past year. Embarrassed by his skin, he has not been in a swimming pool for over ten years. His EASI was 50, DLQI 26, IGA 4, PP-NRS 10, and BSA 49% (Figure 2A [face – back – legs]).

Having tried numerous moisturizers, TCS, 12 years of nbUVB phototherapy, antihistamines (up to 4 times approved dosing), and multiple cycles of prednisone, he continued to suffer from his skin condition. He was enrolled in a lebrikizumab clinical trial, which helped his AD and pruritus but did not clear his face and neck. However, during the clinical trial, he suffered a non-treatment-related posterior cerebral artery infarct, which has deterred him from future biologic use. The patient redeveloped generalized erythema, lichenification, and scaling off the biologic.

The rationale for starting abrocitinib stemmed from numerous conversations with the patient, during which he highlighted his preference for QoL over mere survival. He was desperately seeking to sleep through the night and regain control of his life. Use of immunosuppressants such as methotrexate and cyclosporine were contraindicated in this patient due to his heavy alcohol use and hypertension, respectively. Given his AKC, dupilumab, and tralokinumab were eliminated as options to reduce the risk of worsening his ocular involvement. The lower perceived rates of MACE and VTE events with abrocitinib compared to upadacitinib led to the patient being started on abrocitinib. Two weeks prior to starting abrocitinib, he received his first dose of the shingles vaccine. The decision was made to start at 50 mg of abrocitinib to mitigate any potential risk for drug interactions or adverse cardiovascular events. He reported that during his first week on abrocitinib, he was able to sleep itch-free every night and noticed smoother skin texture. After one month of monitoring without any adverse events nor appreciable changes in blood values, the patient was increased to 100 mg abrocitinib. After two weeks on 100 mg abrocitinib, the patient’s EASI was reduced to 6.4, DLQI to 6, IGA to 2, PP-NRS to 1.5, and BSA to 10% (Figure 2B [face – back – legs]). The patient remains on 100 mg of abrocitinib with good control of AD, itch, and good tolerability.

Learning point: Assessment of risks and benefits with a patient remains an important consideration in the TTT paradigm for AD treatment. While extra precautions must be considered in a complex medical patient, their complexity does not preclude them from abrocitinib therapy. Titration of the abrocitinib dose, starting at 50 mg, may also help minimize any potential risk while simultaneously allowing patients to benefit from treatment.

Figure 2: 63-year-old medically complex male with anxiety, depression, hyperlipidemia, hypertension, and a history of stroke
(Photos courtesy of Lyn Guenther MD, FRCPC)

Case 6. The busy professional biologic naïve patient needing a fast-acting therapy

A 38-year-old lawyer of Asian (FST4) descent presented to the clinic in search of a rapid solution for his AD. He had no significant past medical history other than lifelong AD. At presentation, his DLQI was 28, EASI was 50, and IGA was 4 (Figure 3A [face – legs]). He had only previously tried betamethasone 0.1% cream and prednisone with mild, transient improvement after each therapy. Despite being naïve to systemic therapies beyond prednisone, he wanted a quick, easy solution to his skin condition that would not impact his busy schedule and allow him to enter conference rooms with confidence. Understanding the patient’s aggressive treatment goals, the provider started him on 200 mg of abrocitinib with concomitant use of tacrolimus ointment 0.1% twice daily, as needed. Four weeks later, the patient returned with 90% skin clearance, including complete clearance on his face and only post-inflammatory erythema remaining on his extremities (Figure 3B face – legs]. At his 6-month follow-up, he had clear skin (Figure 3C [legs]). While he was given the option to reduce to the 100 mg dose, the patient has been reluctant to decrease the dosage given his rapid, lasting response to the current abrocitinib 200 mg regimen.

Learning point: The 200 mg dose of abrocitinib may be an optimal first-choice therapy for select patients. The JAKi allows for fast results, and the ease of a once-daily pill makes it an ideal option for working professionals with hectic lives. The 100 mg and 200 mg abrocitinib dosing options also allow patients to choose how aggressively they would like to treat their AD while relying on their provider to help them weigh the risks and benefits.

Figure 3: 38-year-old biologic naïve male
(Photos courtesy of Andrei Metelitsa MD, FRCPC)

Case 7. The dupilumab failure AD patient

A 62-year-old (FST3) male with generalized AD since adolescence was initiated on 100 mg of abrocitinib therapy. Having struggled most of his adult life with daily TCS and emollient regimens, the patient was frustrated as his AD had a determinantal impact on his daily activity, social life, sports participation, and sleep. He had previously tried one year of dupilumab treatment with an inadequate response. Prior to starting abrocitinib, his EASI was 12, IGA 3, and PP-NRS 8. After two weeks on abrocitinib, the patient had an EASI of 3.2, IGA 1, and PP-NRS of 1. Despite reporting nausea from therapy, he expressed 8 out of 10 satisfaction, given his dramatic skin response. At his 4-week follow-up, the patient had an EASI of 2.1, IGA 1, and PP-NRS of 1, with resolution of his nausea and no further adverse events.

Learning Point: Abrocitinib is an ideal step-up therapy for patients who have an inadequate response to dupilumab. The differing mechanisms of action of abrocitinib and dupilumab make the trial of abrocitinib worthwhile in a patient who may have failed IL-4 receptor blockade. Nausea, when and if it occurs, often resolves spontaneously.

Case 8. The patient intolerant to dupilumab

Struggling with AD since childhood, a 47-year-old female (FST4) with mild asthma and severe AD presented after 16 months of dupilumab therapy. While dupilumab was effective for the first year, her skin failed to maintain its initial response. She had also developed persistent conjunctivitis secondary to dupilumab use. AD covered her trunk, face, and proximal extremities and often caused her to miss work and avoid romantic and social relationships. She struggled to sleep through the night without scratching. In the past, she had tried topical tacrolimus and clobetasol without any lasting improvements. The rationale for starting 100 mg abrocitinib was intolerance and failure to maintain response to dupilumab. On Day 0, her EASI was 35, IGA 4, and PP-NRS score 8. Upon starting abrocitinib treatment, the patient reported mild nausea that improved when the tablet was taken with food. By week 4, the nausea had resolved, and the patient had an EASI of 16, IGA of 2, and PP-NRS of 3. She reported feeling more confident in her skin, with reduced pruritus and improved sleep and quality of life. Without experiencing any other side effects, the patient remains on 100 mg of abrocitinib and is highly satisfied with the treatment.

Learning Point: The side effect profile for abrocitinib does not include conjunctivitis or any other ocular effects, making it ideal for patients sensitive to the adverse reaction of dupilumab or tralokinumab or patients with comorbid ocular conditions. Lastly, nausea is a common adverse effect of abrocitinib therapy that usually resolves with time and may be mitigated by taking the medication with food.

Case 9. The patient with adult-onset AD

The 49-year-old (FST2) male presented with a 4-year history of adult-onset AD. He had a remote history of alcohol-induced pancreatitis but no other comorbidities. Expressing high levels of frustration with his inadequate sleep and intractable itch, the patient wanted rapid control of his pruritic skin. He had tried TCS, TCI, and cyclosporine without sustained skin improvement, and he experienced deterioration of his kidney function from cyclosporine. His EASI was 25, IGA 4, and PP-NRS score 9. The rationale for starting abrocitinib was that the patient was desperate for rapid control. While upadacitinib was considered for rapid pruritus relief, the patient’s history of alcoholism made abrocitinib a safer option as it does not require monitoring of liver function tests. After four weeks of abrocitinib 100 mg daily use, the patient no longer required use of TCS and had an EASI of 1.2, IGA of 2 and PP-NRS of 4. He was extremely satisfied with treatment and tolerated the treatment without any adverse events.

Learning Point: Immunosuppressants such as cyclosporine and methotrexate have long been used to treat AD, although Health Canada does not approve them for treating AD. In addition, these immunosuppressants are often associated with kidney toxicity (cyclosporine), liver and bone marrow toxicity (methotrexate) as well as malignancy (both medications). Thus, long-term use of these immunosuppressants is not appropriate for long-term use in AD patients. In addition, the increasing availability of efficacious, safe, and targeted treatments for AD makes the use of broad immunosuppressants inappropriate.

Case 10. The AD patient switching from another JAK inhibitor

The 21-year-old (FST4) male university student presented with severe AD involving his torso and limbs. His AD first presented in childhood. He had a positive family history of atopic disease. Having tried TCS, crisaborole, and a 2-year course of methotrexate without improvement, the patient was started on upadacitinib. While the upadacitinib helped to significantly clear his skin, he developed acneiform lesions on his face which led to treatment cessation. His AD returned upon upadacitinib cessation (EASI 24, IGA 4, and BSA 30%). A healthy young man, the patient was offered to start at the higher 200 mg dose of abrocitinib, which should allow for faster control of his AD and a quicker return time to being more productive at school. At his 4-week follow-up, the patient had an EASI of 1.2, IGA of 2, and BSA of 3%, with the most considerable improvement on his face and neck. The patient reported mild nausea a few hours after taking abrocitinib; however, the nausea abated when he started taking it with food. Interestingly, he did not experience acne on abrocitinib.

Learning Point: Abrocitinib is a good treatment option for patients who had adverse reactions to another JAKi. There is a low risk of acne as an adverse reaction to abrocitinib versus upadacitinib. Thus, if a patient develops acne on one JAKi, it does not preclude them from trying abrocitinib.

Discussion

Real-world cases provide highly impactful insight into patient and provider experience with a new treatment. Without a cure, the AD treatment goal is aimed at reducing symptoms to a level that has minimal or no impact on patient QoL. In the patient cases discussed above, all patients had previously tried and failed topical therapies such as TCS, TCI, and various emollients and moisturizers. While some had tried systemic therapies, a few were naïve to systemic AD therapies prior to starting abrocitinib. Each patient discussed had a complete or near complete response by week 4 of abrocitinib therapy and reported significant satisfaction with treatment. This real-world case discussion provides invaluable insight into abrocitinib use in a diverse population of Canadian patients suffering from moderate-to-severe AD.

Biologic Naïve Patients

The 2018 consensus-based European guidelines for the treatment of adult AD only recommend the use of dupilumab in severe AD.⁶ While JAKi’s were not yet approved when these guidelines were released, clinical experience suggests that many practices do not recommend JAKi until a patient has failed all other standard therapies, such as dupilumab and other immunosuppressants. However, panel members discussed five cases of biologic-naïve patients with safe, efficacious, and accessible treatment with abrocitinib. The patients’ successful treatment with abrocitinib as a second-line therapy after topicals suggests that requiring a patient to cycle through a biologic prior to a JAKi may be unnecessary. Biologic naïve patients reported being “thrilled” and “very satisfied” with abrocitinib oral dosing that provided rapid itch relief and improvement in QoL.

Dupilumab Failed/Intolerant Patients

Another recurring rationale for initiating a patient on abrocitinib therapy was previous inadequate response or intolerance to dupilumab treatment. Three patients presented had previously been on dupilumab and stopped either due to inefficacy, failure to maintain response, or secondary conjunctivitis. Switching to abrocitinib after prior dupilumab therapy had no effect on the JAKi’s efficacy. Each patient saw near complete response to abrocitinib on either 100 mg and 200 mg dosing approaches. Failure to maintain response to dupilumab may stem from the monoclonal antibody’s ability to trigger the development of anti-drug antibodies (ADA).¹⁷ Some reports show a 7.61% ADA incidence in dupilumab studies, which may be higher in sporadic dupilumab injectors.¹⁸ Abrocitinib, a small-molecule JAK inhibitor, does not trigger the production of ADAs, which may contribute to greater maintenance of initial response.¹⁸ In one-year clinical trials, JADE EXTEND for abrocitinib and LIBERTY AD CHRONOS for dupilumab, 60.5% of patients on abrocitinib 200 mg exhibited an IGA 0/1 at week 48 while only 40% of patients on dupilumab 300 mg weekly and 36% of patients on dupilumab 300 mg biweekly exhibited an IGA score of 0/1 at week 52.^19,20

Jumping JAKi’s and Adverse Reactions

To date, two systemic JAKi’s, upadacitinib and abrocitinib, are indicated in Canada for AD treatment. The most common adverse reactions to abrocitinib include nasopharyngitis, nausea, headache, herpes simplex, increase in blood creatinine phosphokinase, dizziness, urinary tract infection, fatigue, acne, and vomiting. Acne occurred in 4.7% of patients on 200 mg abrocitinib and 1.6% of patients on 100 mg abrocitinib in placebo-controlled trials.⁸ While upadacitinib shares many similar adverse reactions to abrocitinib, 16% of patients on 30 mg and 10% on 15 mg of upadacitinib developed acne during placebo-controlled clinical trials.¹⁴ Case 10 illustrates that patients who develop acne on upadacitinib may not have this adverse event on abrocitinib.

In the real-world cases presented, nausea was the most common adverse event experienced by four patients in the series. The nausea was reported to subside over time or when counseled to take abrocitinib with food. Reactivation of the varicella-zoster virus (VZV) has also been reported in approximately 1% of abrocitinib-treated patients.¹³ The panel suggests shingles vaccination in conjunction with JAKi use. Two presented cases reported that first dose shingles vaccination occurred two weeks prior to abrocitinib start.

Dosing Approach

Abrocitinib is unique in that it offers three potential dosing strategies: 50 mg, 100 mg, and 200 mg.⁸ Depending on preference, patients and providers may choose to start at a higher dose and titrate down or start at a lower dose and titrate up. Considering patient factors, disease factors, and concomitant medications, providers should work with their patients to choose the best dosing strategy for them.

Abrocitinib is predominately metabolized by CYP2C19 (~53%) and CYP2C9 (~30%); thus, co-administration of abrocitinib with a strong CYP2C19 and CYP2C9 inhibitor is not recommended and may increase the risk of adverse reaction to abrocitinib.⁸ Case 5 had a history of cerebral infarct and anxiety treated with CYP2C19 inhibitor, clopidogrel, and CYP2C19 substrate, citalopram, respectively. Despite his complex medical history, because of the impact of his severe AD on his QoL and sleep (he only slept three nights/year pre-abrocitinib), he was initiated on 50 mg of abrocitinib to assess safety. He tolerated the regimen without any adverse reactions. The 50 mg abrocitinib allows for further dose titration in patients with poor renal function or who are poor CYP2C19 metabolizers.

While extra caution must be taken, the panel agreed that patients with complex medical histories should not be excluded as potential candidates for abrocitinib without first evaluating the risks and benefits and having a thorough discussion with these patients.

Future Directions

The panel agreed that patient testimonials are highly impactful and educational. Patients are often enthusiastic about sharing their experiences. In the future, it will be important to direct discussions toward more complex AD cases to help healthcare providers choose appropriate dosing strategies and treatment regimens with the proper precautions. Further investigation into AD-associated PIH in individuals with sensitive skin may also help elucidate therapy plans for all skin types. Lastly, one panel member suggested further training of other medical specialties outside of dermatology in order to earlier recognize and appropriately treat AD patients. In particular, emergency medicine (EM) practitioners come in frequent contact with AD patients suffering from recurrent infections or exacerbations. Educating EM providers may allow for faster AD treatment and reduced patient suffering.

Conclusion

The real-world cases presented reflect the expert panel’s clinical experience with abrocitinib for the treatment of patients with moderate-to-severe AD. The panel’s cumulative insight suggests that abrocitinib is a safe, effective, and rapid-acting AD therapy that may be used in all Fitzpatrick skin types and disease stages. Through a multi-option dosing approach, abrocitinib fosters a TTT paradigm that allows patients and providers to form successful, individualized AD treatment plans.

Limitations

The presented cases represent real-world experience with abrocitinib. All outcome measures were reported from providers in the clinic and reflect real-life data rather than data from a controlled, clinical trial environment. Actual experience with abrocitinib may differ with each patient and/or provider. Our expert panel included general dermatologists and did not include specialized pediatric dermatologists. Thus, this discussion does not provide real-world experience in a pediatric setting. Off-label use of abrocitinib is up to the discretion of treating healthcare providers.

Abstract

Psoriasis vulgaris is a chronic, immune-mediated inflammatory skin disease affecting 2-4% of the Canadian population. Lifelong management is required. While most psoriasis vulgaris cases are mild-to-moderate (>80%) and do not require systemic treatment, these cases can still be particularly challenging to treat as topical therapies present limitations, including efficacy and administration, leading to poor long-term treatment compliance and unsatisfactory treatment responses. The intent of this paper is to provide physicians with a clinically relevant review of the currently available and newly developed topical therapies for psoriasis, the practice guidelines for topical management of mild-to-moderate psoriasis, and the common pitfalls and mitigation strategies to encourage long-term treatment compliance.

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Introduction

Psoriasis is a common immune-mediated skin disease affecting ~2-4% of the population in North America.¹ In nearly one-third of cases, disease begins during the first 2 decades of life and follows a chronic and persistent course, resulting in high cumulative lifetime disability.² Psoriasis is divided into 4 major clinical forms, including plaque psoriasis, guttate psoriasis, erythrodermic psoriasis and pustular psoriasis.³ Plaque psoriasis represents >90% of cases and will be the focus of this review. Classically, plaque psoriasis affects the trunk as well as the extensor surfaces of the elbows and knees; it can also affect other body sites, giving rise to regional variants such as scalp, face, intertriginous, palmoplantar, genital and nail psoriasis.³

Because psoriasis is often localized to visible and/or special body sites (knees, elbows, trunk and scalp) and is commonly associated with pain and itch, it often causes significant physical and psychological burdens.⁴ Stigmatization is common and contributes to poor health-related quality of life (HRQoL), elevated risk of multiple health comorbidities, and increased barrier to treatment.⁵ Indeed, a recent Global Burden of Disease (GBD) study ranked psoriasis as the second contributor to all skin-related Disability Adjusted Life Years (DALYs).⁶ The GBD study highlighted an increase in prevalence and morbidity of psoriasis globally, with North America and Europe being particularly affected, emphasizing the significant burden that psoriasis imposes on both individuals and society as a whole.⁶

Mild, moderate, and severe psoriasis are defined as plaques affecting <3%, between 3-10%, and >10% of body surface area (BSA), respectively.¹ Much progress has been realized in regards to managing severe disease with the approval of numerous advanced systemic therapies, including biologics and small molecules.⁷ Unfortunately, in contrast to severe disease, there has been very limited advancement in the management of mild-to-moderate disease, which affects >80% of the psoriatic patient population.^8,9 Mild psoriasis is typically managed with lifelong skin-directed topical therapies.¹⁰ Topical therapies are also often used to treat severe psoriasis vulgaris, either as monotherapy or as an adjunct to phototherapy and/or systemic therapy.¹⁰

The most commonly used topical therapies in psoriasis include corticosteroids, vitamin D3 analogues, retinoids, calcineurin inhibitors, keratolytics and tar. Multiple fixed-ingredient combination products have become commercially available in the last 20 years with the aim to overcome challenges related to lack of efficacy, compliance and adverse events.¹¹

Our objective is to review: 1) the currently available and newly developed topical therapies, both single and fixed-dose combination products; 2) clinical practice guidelines specific to the topical treatment of psoriasis; and 3) common pitfalls and mitigation strategies when managing psoriasis with topical therapies. While we recognize the importance of behavioural modification and skin care in the management of psoriasis vulgaris of all severities, we refer the reader to the review article by Ko et al. on the topic.¹²

Literature Search

This narrative literature review included studies that examined currently available therapies for psoriasis from 2010 to present. The review was conducted using the PubMed and Embase databases with the following search terms: (psoriasis) AND [(corticosteroids) OR (topical corticosteroids) OR (topical corticosteroids AND salicylic acid) OR (topical corticosteroids AND coal tar) OR (calcipotriol) OR (calcitriol) OR (tacalcitol) OR (pimecrolimus) OR (tacrolimus) OR (tazarotene) OR (retinoids) OR (corticosteroid* AND calcipotriol) OR (corticosteroid* AND calcitriol) OR (corticosteroids AND tazarotene) OR (roflumilast) OR (tapiranof) OR (topical treatment)] as either keywords or MeSH terms. Clinicaltrials.gov website was also searched for ongoing Phase II and III clinical trials. References of identified manuscripts were manually extracted to identify additional articles. Only articles published in English were considered. Articles were included if they reported on treatment of psoriasis in humans, regardless of study type. All publications were independently assessed by SG and EN first by screening titles, then abstract, followed by full-length manuscripts. Any discrepancies were discussed and resolved.

Topical Therapies for Psoriasis – Our Current Toolbox

Psoriasis is a chronic disease that requires a life-long treatment. Most patients are managed with topical treatments, therefore, it is important to recognize all presently available therapeutic options, taking into account their respective efficacy, safety profile, and usage considerations. Currently, available treatments that will be discussed include topical corticosteroids (TCS), vitamin D3 analogues, calcineurin inhibitors (TCI), tar-based preparations, retinoids, and combination therapies.¹³ These therapies can be used to induce skin clearance and to maintain disease control.¹⁴ Monotherapies with dithranol and salicylic acid will not be discussed, as their clinical use is limited. A clinical timeline of topical therapies for psoriasis is provided in Figure 1. This section will first discuss efficacy and safety considerations of monotherapies followed by combination treatments. Novel therapies, established or previously published guidelines for topical medications use and general recommendations to improve compliance are discussed in following sections.

Monotherapies

Topical Corticosteroids (TCS)

TCS have been used to treat psoriasis for over 60 years.¹⁵ TCS exert broad anti-inflammatory, immunosuppressive, and antimitotic effects.¹⁶ The most recent systematic review that we have identified focusing on TCS efficacy and safety in psoriasis dates back to 2012.¹⁵ It included 50 randomized controlled trials (RCTs), of which only 11 were placebo controlled. Potent and ultra-potent TCS were used in different formulations to induce and/or maintain disease control. Only 5 studies used the Psoriasis Area and Severity Index (PASI) assessment tool to measure efficacy outcomes. The mean percentage change in the PASI from baseline to 4-8 weeks ranged from 45-60%. However, the overall reported efficacy rating varied greatly depending on the study. An added benefit of occlusion was suggested (1 study), whereas no efficacy difference was established between different vehicles (2 studies). Three studies confirmed that weekend (or episodic) TCS treatment after achieving skin clearance was valuable to prevent plaque recurrence in 30-40% of patients at 6 months.

Since this publication, we identified 2 additional RCTs.^17,18 Desoximetasone 0.25% spray twice daily (BID) demonstrated statistically significant clinical success compared to the vehicle as measured by Physician Global Assessment (PGA) score 0/1 at 4 weeks (39% vs. 7%, respectively).¹⁷ Efficacy was better among compliant patients who received reminders compared to those that were not reminded, suggesting that compliance is an important barrier to treatment success.^18-20 Another RCT compared once daily (QD) halobetasol propionate 0.05% cream vs. halobetasol propionate 0.01% lotion suggesting similar efficacy at 2 weeks.²¹

Despite corticosteroid-sparing alternatives and combination therapies (discussed below) being commercially available, TCS remain widely used because of the low cost of some products as well as their versatility. They are available in a wide range of vehicles and potencies, ranging from I (ultra-high potency) to VII (low potency). Available vehicles include creams, lotions, foams, gels, ointments, shampoo, sprays, and solutions²² (Table 1). Typically, potent to ultra-potent TCS (class I-II) (e.g., clobetasol propionate) are used for thick plaques on the trunk/limbs or special sites, such as the scalp and palmoplantar regions; moderate potency TCS (class III-IV) (e.g., betamethasone valerate; triamcinolone acetonide) are suitable for thinner plaques on the trunk/limbs, whereas mild potency TCS (class VI-VII, e.g., desonide; hydrocortisone) are recommended for intertriginous areas, genitals and/or face.²² Milder potency preparations are also usually preferred to manage psoriasis in pediatric or pregnant patients.^23,24 The choice of the vehicle is made by the treating physician together with the patient. While some vehicles are preferred based on the anatomic site being treated and desired potency, patient preference is of utmost importance since this enhances treatment compliance. An RCT of vehicle preference among various TCS preparations assessed adherence to treatment and improvement of HRQoL among patients with psoriasis between spray, cream, ointment, gel, lotion, foam, and solution.²⁵ It was found that patient preference was highly variable, with less messy products favoured.²⁵ There was no overwhelming agreement on the effect of TCS vehicles in terms of efficacy, hence treatment should be individualized.

Table 1. Topical Corticosteroid Classes of Potency

Adverse events (AEs) with TCS use are generally rare, but may occur with prolonged and/or inappropriate use. These include local AEs such as skin atrophy, telangiectasia, striae, poor wound healing and infections. When used on the face or acne-prone skin, acne exacerbation or de novo periorificial dermatitis/folliculitis may occur.²⁶ Furthermore, even class VII TCS used on eyelids for prolonged periods can lead to cataracts and/or glaucoma.²⁷ Systemic AEs related to hypothalamic-pituitary axis (HPA) suppression are exceedingly rare.^28,29 Two systematic reviews/meta-analyses evaluated TCS safety in psoriasis. Literature identified was reassuring, with <5% risk of skin atrophy³⁰ and <5% rate of HPA suppression when TCS were used long-term.³¹ TCS withdrawal reactions, such as Red Skin Syndrome or topical steroid addiction, have also been reported with discontinuation of prolonged, frequent use of moderate to high potency TCS.³² These severe reactions are rare and are more likely to occur with use on special areas, such as the face and the genitals. A recent review article concluded that TCS are generally safe and effective when used correctly for short periods of time or with short breaks in longer treatments.³² Beside AEs, additional TCS related limitations include potential tachyphylaxis and corticophobia. Whether tachyphylaxis truly exists is debated among experts, as diminished efficacy over time may be related to low adherence to treatment among patients, especially when long-term treatment is required.³³ Corticophobia among patients and health care providers remains omnipresent and is a major barrier for treatment efficacy beyond inherent limitations associated with the drugs of this class.³⁴

Vitamin D3 Analogues

The introduction of Vitamin D3 analogues ~30 years ago was met with much enthusiasm due to their steroid-sparing effect.³⁵ Commercially available vitamin D3 analogues in Canada are calcipotriol and calcitriol ointments. Vitamin D3 analogues may be used as monotherapy, as an adjunct to TCS, or as fixed-dose combination therapy. They work by regulating gene transcription, modulating keratinocyte proliferation, and differentiation.³⁶ The mechanism of action also involves the inhibition of T cell proliferation and downstream inflammatory mediators.³⁶

There are several systematic reviews published assessing the efficacy of vitamin D3 analogues compared to vehicle or TCS.^37-41 As monotherapy, 1 review reported treatment success (defined as >90% reduction in the PASI score) with vitamin D3 analogues ranging from 4-40% after 6-12 weeks of therapy.³⁷ Another reported a decrease in the PASI ranging from 27.8-60.4% with calcipotriol monotherapy.³⁸ Further, BID use of vitamin D3 analogues was found to be at least as effective as TCS and more effective than placebo at 8 weeks.^38,39 A systematic review focused on efficacy of vitamin D3 analogues in pediatric psoriasis patients found 5 studies reporting improvement in PASI from baseline ranging from 17.3-94%, 1 study reporting improvement in Psoriasis Scalp Severity Index (PSSI) of 32.1%, and 1 study reporting 100% clearance of skin lesions.⁴⁰

In the last 10 years, only 2 new double-blind, vehicle-controlled phase III RCTs evaluated the efficacy and safety of calcipotriol 0.005% foam BID for mild-to-severe psoriasis (defined as plaque psoriasis involving 2-20% BSA) compared to vehicle.⁴² Both studies demonstrated significant treatment success, defined as the Investigator’s Static Global Assessment (ISGA) scores of 0/1 at 8 weeks. The primary outcome was achieved in 15% vs. 7% of calcipotriol vs. vehicle patients in the first study and 28% vs. 6% in the second study.⁴²

The use of vitamin D3 analogues in psoriasis has been shown to be safe and well-tolerated, with less AEs than TCS. AEs are generally comparable to the vehicle, with application site reactions occurring in less than 2% of subjects.⁴² Specifically, these include stinging, burning, and peeling of the skin.^37,43 Calcitriol may cause less irritation in sensitive areas compared to treatment with calcipotriol.⁴⁴ When used appropriately (maximum recommended dose of 100 g per week of calcipotriene or 200 g per week of calcitriol), the risk of hypercalcemia is very low.⁴³ Hypercalcemia risk was studied in 3 studies, occurring at a rate <1%.³⁷

Retinoids

Vitamin A and its naturally occurring and synthetic derivatives are referred to as retinoids.⁴⁵ They were introduced as a treatment for cutaneous disorders in the 1960s and, with the development of safer synthetic retinoids, have become widely used.⁴⁵ There are many topical retinoids used in dermatology, however, only tazarotene has been studied and indicated for psoriasis. While tazarotene lotion 0.045% is the only formulation commercially available in Canada, it is indicated for acne and used off-label for psoriasis. Tazarotene binds and modulates activity of retinoic acid receptors (RAR)-β and -γ, thereby decreasing inflammation and keratinocyte proliferation.⁴⁶

There were 2 systematic reviews assessing the efficacy of topical retinoids in psoriasis. The first contained 4 studies comparing tazarotene 0.05% or 0.1% gel or cream to placebo, finding tazarotene to be more effective in improving symptoms in the short-term (6-12 weeks).³⁹ However, the more recent systematic review comparing the same interventions found that symptom clearance as measured by Investigator’s Global Assessment (IGA) ranged from 5.5-6.2% with tazarotene 0.05% and 0.1% cream at 12 weeks, which was not better than placebo.⁴⁷ In the last 10 years, there have been no new published RCTs assessing the efficacy of topical retinoid monotherapy in psoriasis. Most clinical trials have focused on combination therapy of tazarotene and TCS.

The most common AEs associated with use of tazarotene are cutaneous local irritations such as peeling, erythema, itching, and burning at the site of application.⁴⁶ Cutaneous absorption of topical retinoids is limited, and there are no known systemic toxicities. However, as retinoids are teratogenic, women of childbearing age must use appropriate contraception.⁴⁶

Calcineurin Inhibitors (TCI)

Topical calcineurin inhibitors (TCI) have been approved since the early 2000s for the treatment of mild-to-moderate atopic dermatitis. While not indicated for psoriasis, TCI are often used off-label for facial and intertriginous psoriasis to avoid TCS-related AEs.⁴⁸ The available formulations are pimecrolimus 1% cream and tacrolimus 0.1% and 0.03% ointments. TCI bind to immunophilins, which lead to a decreased release of interleukin (IL)-2 and interferon (INF)-γ and thereby decreased T cell proliferation.⁴⁹

Systematic reviews assessing the efficacy of TCI for psoriasis confirmed tacrolimus superiority to placebo, TCS and calcitriol in treating facial and intertriginous psoriasis with treatment duration of 8 weeks.^50,51 However, pimecrolimus was inferior to standard psoriasis treatments.^50,52 One systematic review looked at the synergistic effect of TCI and TCS, which found that there was no additional benefit by combining these agents as opposed to TCS alone.⁵³

In the last 10 years, there have been 2 new RCTs published assessing the efficacy of TCI in psoriasis. The first studied the use of pimecrolimus 1% cream in the treatment of intertriginous psoriasis compared to placebo, finding that 71.4% in the treatment group reported an IGA of 0/1 at 8 weeks.⁵⁴ The second assessed tacrolimus 0.1% ointment in the treatment of nail psoriasis on 1 hand, using the other hand as a control. At 12 weeks, there was statistically significant improvement in the treated hand as evaluated by the Nail Psoriasis Severity Index (NAPSI) score.⁵⁵

AEs for topical TCI include skin irritation and discoloration to the site of application.⁵⁶ In 2006, a black box warning was issued for a potential link with skin cancer and lymphoma.⁵⁶ However, as a result of subsequent large-scale studies disproving this association,⁵⁷ Health Canada lifted the black box warning in 2021.⁵⁸ The systematic reviews and RCTs found similar rates of AEs between treatment and placebo groups,^51,54 however patients should be counselled regarding transient burning sensation when prescribed tacrolimus ointment to improve treatment adherence.

Tar

Historically, coal tar was considered a classic anti-psoriatic therapy and was used as a first-line agent for more than 2,000 years to treat psoriasis and other skin diseases.⁵⁹ Recent studies shed light into the mechanism of action of tar, suggesting modulation of epidermal differentiation and anti-inflammatory effects are likely achieved through activation of the aryl hydrocarbon receptor (AHR).⁵⁹ The efficacy of coal tar or its distillate, liquor carbonis detergens (LCD), in treating psoriasis was seldom formally evaluated. The limited available data suggests inferior efficacy to other commercially available agents. Specifically, a Cochrane Review (last updated in 2013), identified tar (including LCD) as generally less effective than TCS and vitamin D3 analogue monotherapies.⁴¹ Safety has been another important concern. As the “crude” word suggests, coal tar contains >10,000 organic compounds, including carcinogenic chemicals, such as benzene.⁵⁹ However, carcinogenic potential has not been proven.⁶⁰ Over-the-counter tar-containing products are available in different formats including lotions, creams, ointments, and shampoos, however, its application can be messy by staining hair, skin, nails, and clothing with a very unpleasant odour.⁶¹ While it can be compounded with TCS and other active ingredients to enhance effectiveness and penetration, currently it is primarily used in shampoos for the treatment of scalp psoriasis.⁶¹

Combination Therapies

Combination therapies were developed to improve treatment efficacy as it provides 2 mechanisms of action simultaneously and may have additive or synergistic effects.⁶² Further, they may decrease AEs related to each ingredient alone and are therefore better tolerated than monotherapy.⁶² Specifically, vitamin D3 analogues and retinoids decrease the risk of skin atrophy, whereas TCS decreases the irritation associated with vitamin D3 analogues and retinoids. Additionally, most fixed-dose combination topical therapies are prescribed to be applied QD as opposed to BID, thereby potentially improving long-term compliance. Commonly prescribed fixed-dose combination topical therapies include TCS and salicylic acid, TCS and vitamin D3 analogues (commercially available since 2001 as ointment, 2012 as gel, and 2016 as aerosol) as well as TCS and retinoids (commercially available as lotion since 2020).

Topical Corticosteroids and Keratolytics

Keratolytic agents, such as salicylic acid and urea, can improve the efficacy of TCS, especially for thicker plaques, by enhancing penetration and improving skin barrier. They are commercially available in combination as salicylic acid 3.0% and betamethasone dipropionate 0.05% ointment and salicylic acid 2.0% and betamethasone dipropionate 0.05% lotion. Additional alternatives can be compounded. There were several RCTs assessing combination therapy of salicylic acid and TCS showing superiority to monotherapy of either salicylic acid or the TCS alone.^53,63 However, 2 RCTs compared combination therapy of TCS and salicylic acid to calcipotriol monotherapy, with no clinical difference.⁶⁴ HRQoL was however improved with the combination therapy and was preferred by patients.⁶³ Only 1 RCT assessed urea in combination with TCS, which found a greater percentage of patients with an improved clinical score compared to monotherapy (47% vs. 33%).⁶³ Similarly, recent data showed that even simple moisturizers containing lipid-ceramides improve the efficacy of TCS.^65,66 In the last 10 years, there have been no newly published RCTs assessing the efficacy of topical salicylic acid and TCS combination therapy in psoriasis. Although rare, there is a risk of salicylic acid toxicity with topical application.⁶⁷

Calcipotriol and Betamethasone Dipropionate Fixed-Dose Combination

Calcipotriol 50 μg/g and betamethasone dipropionate 0.5 mg/g (Cal/BD), available in ointment, gel, and foam formulations in Canada, allows for both anti-inflammatory and anti-proliferative effects. A large Cochrane systematic review published in 2013 assessed the efficacy of combination therapies in psoriasis. Cal/BD was superior to placebo^41,68 and monotherapy (Cal or BD alone) in all but 1 RCT as early as after 2-8 weeks of treatment.⁴¹

In the last 10 years, there have been many new RCTs assessing the efficacy of Cal/BD for psoriasis focusing on the newer foam formulation, which when used QD for 4-12 weeks demonstrated a significant decrease in PASI from baseline of ~70%, superior to vehicle or either monotherapy.^69-72 Further, approximately half of participants achieved an IGA of 0/1.⁷³ Two studies compared Cal/BD to betamethasone valerate 0.1% dressing, showing in the first trial no significant efficacy difference at 4 weeks with Cal/BD ointment⁷⁴ and the second trial demonstrated superiority of the Cal/BD foam (at 4 weeks).⁷⁵ Several additional RCTs re-iterated the superiority of Cal/BD therapy vs. vitamin D3 analogue monotherapy.^76,70,77-80

Several RCTs focused on Cal/BD vehicle.^71,72,81 RCTs comparing different vehicles have shown better efficacy and superior HRQoL improvement with the use of Cal/BD foam compared to gel or ointment formulations^71,72,81 and cream compared to suspension.⁸² However, RCTs assessing vehicle preference as determined by patients did not find any significant preferences when comparing gel vs. foam, gel vs. ointment, and ointment vs. topical suspension, determining that individual patient preference should dictate treatment.^83-85 One real-world study found that patients using gel reported greater satisfaction compared to ointment due to ease of use.⁸⁶

One RCT focused on psoriasis relapse prevention following clinical clearance, defined as PGA score 0 or 1 (clear or almost clear).⁸⁷ In this study, both treatment arms received Cal/BD QD for 4 weeks initially to achieve skin clearance and were subsequently randomized into Cal/BD or vehicle biweekly as maintenance treatment. Patients that applied Cal/BD proactively experienced 3.1 relapses per year vs. 4.8 relapses (defined as PGA score 2 or higher) seen in the vehicle group. Median time to first relapse was also longer in the proactive management group (56 vs. 30 days) suggesting that proactive approach may be an interesting alternative to reactive approach for interested patients and could potentially be cost-effective.⁸⁷ As expected, both active treatment and proactive maintenance with Cal/BD were well-tolerated and no cases of skin atrophy were reported in either group.⁸⁷

Tazarotene and Halobetasol Fixed-Dose Combination

The only combination treatment of retinoid with TCS commercially available in Canada is halobetasol 0.01%/tazarotene 0.045% (HP/TAZ) lotion. A systematic review published in 2012 included 7 studies assessing the combination of retinoids (in general) with TCS, supporting superiority of combination as opposed to retinoid monotherapy at 4 weeks.⁸⁸ A recently published systematic review of 5 RCTs demonstrated treatment success, defined as at least 2-grade improvement from baseline in the IGA score and IGA score of 0 or 1 (clear or almost clear), of 32.8-52.5% for HP/TAZ compared to 33.3-34% for HP alone and 18.6% for TAZ alone with treatment duration of 2-8 weeks.⁸⁹

There have been several new RCTs published in the last 10 years assessing efficacy and safety of retinoids and TCS combination therapy. A combination tazarotene 0.05%/betamethasone diproprionate 0.05% (TAZ/BD) applied QD was superior to either agent used as monotherapy in 2 studies.^90,91 Treatment success of QD topical HP/TAZ lotion measured by the proportion of patients achieving IGA 0/1 ranged from 31.3-57.8% with treatment durations of 8-12 weeks,^92-99 which was significantly more effective than vehicle or either ingredient alone. The most frequent AEs reported were dermatitis, pruritus, pain, and irritation,^92,93,98 occurring in 6-20.8% of study participants.^91,97 A single RCT analyed the sensitization and irritation potential of HP/TAZ lotion with treatment duration of 4-6 weeks, finding that the topical did not induce contact sensitization and caused only minimal skin irritation, but significantly less than tazarotene alone.¹⁰⁰

Topical Therapies for Psoriasis – The Pipeline

As reviewed above, our current toolbox of topical therapy options is limited to TCS and a handful of other agents, such as vitamin D3 analogues, retinoids, tar or their combination. While the marketing of steroid-sparing monotherapies and fixed-dose combinations with TCS represents a major step forward in the management of psoriasis, these treatment options possess limitations in terms of efficacy, AEs, cost, patient satisfaction, and real-world adherence. Hence, there remains an unmet need for new topical therapies.¹⁰¹

There is an exciting topical therapy pipeline in psoriasis (Table 2), roflumilast and tapirnarof will be discussed in this section as phase III RCT data was recently published. Roflumilast is a phosphodiesterase-4 (PDE-4) inhibitor that has been developed into 0.3% cream and foam formulations. Crisaborole, a topical PDE-4 inhibitor, was approved in 2016 for atopic dermatitis in adults and children.¹⁰² Its use has been investigated for psoriasis in phase II RCTs, however, despite demonstrating efficacy and safety, results were not published. Rather, focus has shifted to roflumilast, a more potent PDE-4 inhibitor by 25-300X based on in vitro studies.¹⁰² PDE-4 inhibition suppresses the breakdown of cyclic adenosine monophosphate (cAMP), decreasing the presence of proinflammatory cytokines involved in the pathogenesis of psoriasis, similar to apremilast used systemically or topical crisaborole.¹⁰³ Phase I and II RCT data have demonstrated that roflumilast cream QD was superior to the vehicle when used for 2-8 weeks.^104-106 Phase III RCT data regarding roflumilast 0.3% cream efficacy and safety has been recently published.¹⁰⁷ DERMIS-1 and DERMIS-2 were parallel double-blind RCTs including 439 and 442 patients, respectively. Patients aged ≥2 years with psoriasis affecting 2-20% BSA were recruited and randomized 2:1 into either roflumilast 0.3% cream or vehicle applied QD for 8 weeks. The primary outcome was IGA 0/1 response plus ≥2 grade improvement from baseline, which was achieved in 37.5-42.4% of roflumilast-treated patients vs. 6.1-6.9% vehicle-treated patients. Improvement of PASI ≥75% from baseline (PASI75) was achieved in 39.0-41.6% vs. 5.3-7.6% of roflumilast-treated vs. vehicle-treated patients, respectively. It was also shown to be effective for the treatment of intertriginous psoriasis (68.1-71.2% vs. 13.8-18.5%). The incidence of AEs was comparable to the vehicle, with the most commonly reported events being diarrhea and headache in the roflumilast group. Further, AE profiles were similar in individuals aged 12–17 years relative to adults.¹⁰⁷ Currently, roflumilast is approved by the US Food and Drug Administration (FDA) and Health Canada.

Table 2. Topical antipsoriatic agents undergoing clinical trials

Tapinarof is an AHR-modulating agent that acts as an anti-inflammatory compound. It has a similar mechanism of action to tar, which also activates AHRs, however it does not contain carcinogenic chemical compounds.¹⁰⁸ Tapinarof is able to regulate innate and adaptive immune responses, affecting Th17 and regulatory T cells. It also has an important role in the development and maintenance of the skin barrier and upregulating barrier genes, such as filaggrin. Lastly, tapinarof inhibits the migration of T cells, decreasing the presence of proinflammatory cytokines, such as tumor necrosis factor (TNF)-α, INF-γ, IL-2, IL-13 and IL-17A.¹⁰³ Phase III RCT data has been recently published. In 2 parallel double-blind RCTs including >600 patients each, adults with mild-to-severe psoriasis (PGA 2-4, BSA 3-20%) were recruited and randomized 2:1 into either tapiranof 1% cream or vehicle applied QD for 12 weeks. The primary endpoint was IGA 0/1 and 2-point reduction from baseline at 12 weeks, which was achieved in 35.4-40.2% of tapinarof-treated patients vs. 6.0-6.3% of vehicle-treated patients.¹⁰⁹ While it was generally well-tolerated, increased rates of pruritus, contact dermatitis and folliculitis were seen in the active treatment group. A second RCT found that significantly more participants achieved a 75% reduction in the PASI score from baseline (PASI75) with tapinarof (50.4%) compared to calcipotriol (38.5%) and placebo (13.9%) when used QD for 12 weeks.¹¹⁰ Tapinarof has been recently approved by the FDA.

Treatment Guidelines for Topical Antipsoriatic Agents

Treatment guidelines for severe psoriasis and psoriatic arthritis are beyond the scope of this manuscript. This section will focus on reviewing guidelines specific to the treatment of mild-to-moderate psoriasis or treatment focused on topical agents.

Current guidelines for the treatment of mild-to-moderate psoriasis recommend topical therapies which include monotherapy with TCS, vitamin D3 analogues, TCI, retinoids, anthralin, and tar as well as combination therapies as first-line options. In Canada specifically, treatment guidelines were initially published in 2011. At this point, Grade A recommendation for first-line topical therapies included TCS or vitamin D3 analogues (i.e. calcipotriol) monotherapy or Cal/BD fixed-dose combination therapy. The treatment guidelines noted that additional topical therapy options were superior to placebo (e.g., retinoids alone or in combination with TCS, 15% LCD) and may be used on a case-by-case basis.^10,111 An update of these treatment guidelines was published in 2016 adding topical calcitriol as an additional first-line topical therapy option for mild psoriasis.^10,111

The American Academy of Dermatology (AAD) and National Psoriasis Foundation (NPF) have put forth the most recent guidelines in North America in 2020 focusing on topical therapies.¹⁴ The AAD-NPF guidelines do not mention specific recommendations for first-line topical therapy options, but rather provide guidance for use within each class. For TCS, Grade A recommendations include using class I to V agents for up to 4 weeks for body psoriasis (excluding intertriginous areas) and class I to VII agents for scalp psoriasis. The use of TCS for prolonged periods (>12 weeks) may be done under the supervision of a physician (Grade C). However, gradual reduction in frequency of TCS is suggested upon clinical improvement, but without defined tapering protocol. Following clinical improvement, maintenance of response can be achieved by using a steroid-sparing agent (e.g., vitamin D3 analogues or TCI) or by using TCS intermittently (e.g., biweekly, this is also known as proactive approach). Additional recommendations made in regards to TCS use were as follows: the use of emollient was suggested to reduce itching and desquamation and to prevent relapse after TCS discontinuation (Grade B). As well, topical salicylic acid alone or in combination with TCS was recommended as an alternative to TCS monotherapy to achieve clear skin (8-16 weeks of treatment, Grade B).

AAD/NPF guidelines recommended vitamin D3 analogue monotherapy and/or in combination with TCS (e.g., Cal/BD fixed-dose combinations) to induce clearance of scalp psoriasis (4-12 weeks treatment, Grade A), facial psoriasis (up to 8 weeks treatment, Grade B, caution to favour class VI-VII TCS agents) or body psoriasis (up to 52 weeks treatment, Grade A). Topical retinoids (e.g., tazarotene) were recommended either as monotherapy, fixed-dose combination (e.g., HP/Taz) or in combination with narrowband ultraviolet light phototherapy (NB-UVB) (Grade B) for plaque psoriasis and nail psoriasis. However, HP/Taz was preferred (Grade A) to induce clear skin (8-16 weeks treatment) due to better efficacy and tolerability.

The off-label use of TCI (e.g., tacrolimus and pimecrolimus) was recommended by AAD/NPF guidelines for facial and inverse psoriasis to achieve clinical improvement (Grade B recommendation) and to maintain response (Grade C recommendation). They also suggested a combination of tacrolimus/6% salicylic acid for body psoriasis (Grade B recommendation).

Grade B recommendation was also stated for short contact anthralin use (≤2 hours per day, up to 8-12 weeks treatment) and Goeckerman therapy (coal tar and NB-UVB) for mild-to-moderate plaque psoriasis.¹⁴ Coal tar preparations received Grade A recommendation as well.

Real-world Limitations with Topical Treatments and Strategies to Improve Compliance

As highlighted above, all current topical therapies come with limitations. Patient compliance is certainly among the most important barriers to success. Adherence rates with current topical therapies are low, estimated to range from 50-70% in general.¹⁰¹ The compliance rates for TCS are even more variable and in some instances are thought to be as low 8%, due to prevalent corticophobia among dermatology patients.^101,112 Adherence is an important concept that must be evaluated in patients as it is directly associated with better clinical outcomes. A recent RCT demonstrated that a decrease in adherence rate of 10% was associated with a 1-point increase in disease severity.¹¹³

Various interventions were studied to improve compliance. Three RCTs integrated reminders in the forms of BID telephone calls, text messages, or smartphone application to remind and motivate patients to use their topical therapy.^20,114,115 In all studies, adherence improved and almost doubled compared to non-interventional arms (65% vs. 38% adherence).¹¹⁵ This translated into significantly better clinical outcomes, such as reduction in PGA.^20,115 Another RCT developed a web-based application to educate patients with videos, graphics, and text.¹¹⁶ While knowledge was improved, this did not translate to increased treatment adherence.¹¹⁶ Four RCTs approached adherence by offering more clinical support, such as teaching from nursing staff or internet-based reporting.^117-120 Compared to standard of care, these clinical trials demonstrated that additional support resulted in greater clinical outcomes as early as 4 weeks, which were sustained at 3 months.^117-120

Vehicle selection is an important component of efficacy and adherence. Good vehicles can accelerate barrier restoration and enhance efficacy of active agents by promoting penetration and sustained drug release.¹²¹ As discussed above, RCTs assessing patient satisfaction have found that treatment preferences are heterogeneous and may even change over time.^83,122 Factors that may influence preferences included age, sex, comorbidities, disease duration, and prior treatments.¹²² Therefore, a vehicle should be selected to maximize efficacy and meet the diverse needs of the patient while considering bodily location of psoriasis, probability of improvement, and delivery method. An additional very important attribute for a topical therapy to improve patient adherence is convenience. While it may be patient-specific, an agent that does not need to be applied often (QD or less often), is universal (e.g., same product that can be applied anywhere on the skin), is cosmetically acceptable (texture, colour, and odour) and is affordable will likely promote higher patient adherence and thereby achieve better clinical success rates.

As discussed in the guideline review section above, the first aim of psoriasis treatment is to achieve clear/almost clear skin with a topical agent of choice (combined physician/patient decision for agent selection). Prior to fixed-dose combination topical therapies, in order to increase efficacy while mitigating AEs, different strategies were used. These included rotational treatment where patients alternated between 2 agents, usually a TCS and a corticosteroid-sparing molecule;¹²³ or a sequential treatment approach where a superpotent agent (usually TCS class I-II) was used initially with subsequent step down to either a milder TCS, steroid-sparing molecule or a rotational treatment. However, nowadays fixed-dose combination topical therapies are more popular for their additive efficacy, simplicity, and convenience.¹²³ Once acceptable control is achieved, discussion of relapse prevention is important.

Because psoriasis is chronic and likely to recur upon discontinuation of the topical therapy, it is important to educate the patient about the chronicity of the disease and its treatment at the initial and subsequent visits. Two approaches following initial improvement of psoriasis are commonly used in clinical practice to maintain response over longer-term: the proactive and reactive approaches. Combined physician-patient decision-making may opt for either a proactive approach which consists of using the same agent to achieve clear skin (or another topical) intermittently (e.g., biweekly) to psoriasis-prone areas in order to prevent recurrence, or a reactive approach where all treatments are discontinued upon clinical resolution and restarted promptly with first signs of disease recurrence.

Conclusion

The vast majority of our psoriasis patients have a mild-to-moderate disease requiring topical therapies life-long. Consequently, the availability of safe, effective, and convenient products is essential to achieve and maintain clear/almost clear skin and promote long term treatment adherence. In this review, we provided clinicians an up to date safety and efficacy data of commercially available topical products as well as imminent pipeline topicals. North American guidelines for topical treatment of mild-to-moderate psoriasis are summarized as well as clinical tips are provided.

¹Diplomate of the American Board of Dermatology, Fellow of the Royal College of Physicians of Canada, Associate Professor, Department of Medicine University of Toronto, Onco-dermatologist, Princess Margaret Cancer Centre, Director, Toronto, ON, Canada.
²Fellow of the Royal College of Physicians of Canada, Diplomate of the American Board of Dermatology, Associate Professor, Department of Medicine, Division of Dermatology, Laval University, Director Melanoma and Skin Clinic, Le Centre Hospitalier Universitaire de Québec, Hôtel-Dieu de Québec, Quebec City, QC, Canada.
³Medical Oncologist, Medical Oncology Disease Site Lead for Melanoma/Skin Oncology, Department of Medical Oncology and Hematology, Princess Margaret Cancer Centre. Assistant Professor, Department of Medicine, University of Toronto, Associate Member, Department of Immunology, University of Toronto, Toronto, ON, Canada
⁴Radboud UMC, Nijmegen and Andriessen Consultants, Malden, The Netherlands.
⁵Fellow of the Royal College of Physicians of Canada, Associate Professor, Department of Oncology, McGill University; Director, Division of Radiation Oncology, McGill University Health Centre, Montreal, QC, Canada.
⁶Fellow of the Royal College of Physicians of Canada, Diplomate of the American Board of Dermatology, Associate Professor, Department of Medicine University of Toronto, Toronto, ON, Canada, Lynderm Research, Markham, ON, Canada.

Abstract
The Canadian skin management in oncology (CaSMO) project was developed to improve cancer patients’ (both active and survivors) quality of life by offering tools to healthcare professionals for preventing, reducing and/or managing cutaneous adverse events (cAEs).
Immunotherapy, specifically immune checkpoint inhibitors (ICIs), for cancer patients is both increasing in indications and use. Similarly, the incidence and onset of cutaneous immunotherapy-related adverse events (cirAEs) vary based on the class and dose of immunotherapy administered, the type of cancer, and factors related to the patients. Dermatologists will increasingly see side effects from immunotherapy.

The CaSMO advisors developed a practical primer on prevention, identification, and treatment, including skincare for cirAEs, focusing on isolated pruritus, psoriasiform eruptions, lichenoid eruptions, eczematous eruptions, and bullous pemphigoid.
A modified Delphi approach was used for the cirAEs practical primer’s development. Recommendations given by the CaSMO advisers are based on information from the guidelines, algorithms, consensus papers, and systematic reviews coupled with their clinical experience and resulting from discussions.

According to the CaSMO group, the management of cirAEs starts with physician awareness and patient education on the occurrence of toxicities, preventive measures, and skincare using gentle cleansers, moisturizers, and sunscreen started before immunotherapy begins and ongoing thereafter as part of the lifestyle.

Keywords: Immunotherapy, cutaneous adverse events, immune checkpoint inhibitor, skin toxicity, psoriasis, pruritus, morbilliform, eczema, bullous pemphigoid

Disclosures
The authors disclosed receipt of the following financial support for the research, authorship, and/or publication of this manuscript. This work was supported by an unrestricted educational grant from La Roche-Posay Canada. All authors contributed to the manuscript, reviewed it and agree with its content and publication.

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Introduction

In 2021 an estimated 229,200 Canadians were diagnosed with cancer.¹ In Canada, of the four most commonly diagnosed types of cancer (lung, breast, colorectal, and prostate), excluding non-melanoma skin cancer, lung cancer is the most lethal and expected to cause more deaths than the other types combined.^2,3

Immunotherapy activates the body’s immune system to fight cancer. Immune checkpoint inhibitors (ICIs) prevent the deactivating signal by blocking the T-cell shut-off receptors and ligands from binding to each other, thereby disrupting signaling so that T cells remain active and can then recognize and attack cancer cells.^4,5 ICIs are approved for treatment across almost every type of solid-organ tumors, many hematologic malignancies, and in many instances, first-line therapy.^4,5 In 2019, in the United States, approximately 40% of oncology patients were eligible for treatment with immunotherapy.⁶ ICIs may be administered as a single agent (anti-CTLA-4 (ipilimumab), anti-PD-1 (pembrolizumab, nivolumab), anti-PD-L1 (atezolizumab, durvalumab, and avelumab)) or as combination immunotherapy (ipilimumab and nivolumab) and even as a combination with other agents.^4-6

Oncology patients treated with immunotherapy may experience cutaneous immunotherapy-related adverse events (cirAEs) at any time during and after the cancer treatment, severely impacting the quality of life (QoL) and potentially cancer treatment outcomes.^7-24 The incidence and onset of cirAEs vary depending on the drug class, the type of cancer, and factors related to the patient.²⁵ Adverse skin reactions occur in 14%–47% of patients treated with ICIs, ranging from mild and localized to debilitating and widespread in 1%–3% of patients and even potentially causing death.^15,16,26-30 Nivolumab-related cirAEs, including isolated pruritus, occurred in approximately 13–20% of patients, of which 0.7% of patients reported grade three or higher cAEs.^29-33 Pembrolizumab-induced cirAEs occurred in 9%–27% of patients, of which 1%−4% of patients reported grade three or higher cirAEs.^34,35

Frequently occurring cirAEs include pruritus without primary dermatologic findings (isolated pruritus), lichen planus or lichenoid drug eruptions, psoriasiform reactions, eczematoid eruptions, morbilliform eruptions, and bullous diseases, primarily bullous pemphigoid.^7-24  

The cirAEs may indicate a therapeutic response. A multicenter retrospective study on patients with non-small-cell lung carcinoma (NSCLC) receiving nivolumab showed that AEs and cirAEs were a strong predictor of survival outcomes, and those presenting with more than 2 AEs showed more benefit than patients with fewer AEs.¹⁴  Vitiligo occurs in some patients with melanoma receiving ICIs (Figure 1), and this is significantly associated with both progression-free-survival (PFS) and overall survival (OS) which indicated a two to four times lower risk of disease progression and death.^32,36

Major guidelines^10-12 recommend the use of systemic steroids for grade 2 or higher “rash” contrary to evidence showing the use of systemic steroids reduces the anticancer effect of ICIs.³³  A secondary analysis of a randomized trial on stage III melanoma patients with cirAEs showed that patients who received treatment with systemic steroids for 30 days or longer had lower OS than those without steroid treatment.³³  Another multicenter retrospective analysis of patients treated with anti-PD-1 therapy showed that high-dose glucocorticoids used to treat AEs were associated with poorer PFS and OS.³⁵

Scope of the Canadian Skin Management in Oncology Project

The Canadian skin management in oncology (CaSMO) project was developed to improve cancer patients’ (both active and survivors) QoL by offering tools for preventing and managing cAEs.^37-39 A general management algorithm to reduce the incidence of all cutaneous toxicities and maintain healthy skin using general measures and over-the-counter agents³⁸ and an algorithm to reduce and treat acute radiation dermatitis³⁹ were previously published. These algorithms aim to support all healthcare providers treating oncology patients, including physicians, nurses, pharmacists, and other medical providers.^38,39 The next step in the project was to develop a practical primer on prevention, identification, and treatment for cirAEs, focusing on isolated pruritus, psoriasiform eruptions, lichenoid eruptions, eczematous eruptions, and bullous pemphigoid.

Table 1: Immunotherapy classes, molecules, and indications

CTLA-4 impinges on many features of T-cell biology.^43,44  The CTLA-4 signaling pathway and the PD-1/PD-L1/PD-L2 signaling pathway are critical checkpoints that are used to down-regulate the body’s immune system that tumors often exploit and activate, thereby evading the body’s immune system.^43,44 CTLA-4 dampens T-cell responses via cell-intrinsic and extrinsic pathways. Intrinsic events include, among others, inhibition of protein translation, recruitment of phosphatases, activation of ubiquitin ligases, inhibition of cytokine receptor signaling, and inhibition of lipid microdomain formation on the surface of T-cells. Cell extrinsic events include the competition for CD28 in binding to its ligands CD80/86, the removal of CD80/86, the release of suppressive indoleamine-dioxygenase, and the modulation of Treg function. Antibodies to CTLA-4 may facilitate T-cell tumor entry and alter the movement in tumors and rates of egress.^43,44

cirAEs can present as almost any dermatologic condition, but most are inflammatory dermatoses.^7-11,26 The median time to onset of cirAEs is four weeks but has a broad range from 2 to 150 weeks, including beyond treatment discontinuation.^15,17,45

cirAEs of any grade have been reported at 30-40% of patients receiving PD-1/PD-L1 and approximately 50% of patients treated with ipilimumab.³¹  Maculopapular rash and pruritus are common cirAEs related to these treatments.³¹

A systematic literature review on cancer treatment with pembrolizumab and nivolumab observed that the most frequently occurring cirAEs were inflammatory dermatitis, pruritus, and vitiligo.⁴⁶ The rate of any-grade cirAEs with pembrolizumab and nivolumab was reported at 16.7% (RR=2.6) and 14.3% (RR=2.5), respectively.⁴⁶ The cirAEs may be associated with pruritus and comprised of erythematous macules, papules, and plaques, predominantly low-grade and localized to the trunk and extremities.⁴⁶ Challenges with reports of cirAEs are accurate descriptions and diagnoses of the specific dermatoses as many are simply reported as “rash”. Additional cirAEs comprised pruritus [incidence pembrolizumab and nivolumab was 20.2% (RR=49.9) and 13.2% (RR=34.5) respectively] and vitiligo [incidence, 8.3% (RR=17.5) and 7.5% (RR=14.6) respectively].⁴⁵ The researchers noted that knowledge of cirAEs is critical in delivering optimal cancer treatment, maintaining therapeutic agent dose, and health-related QoL.⁴⁶

The advisors agreed that cirAEs are likely an indicator of ICIs treatment efficacy and should be managed with topical treatment and judicious, ideally steroid-sparing systemic treatment where possible.^33,35-38

Approaches to the most common immunotherapy-related cAEs

The advisors discussed and selected the most common cirAEs: isolated pruritus, psoriasiform eruptions, lichenoid eruptions, eczematous eruptions, morbilliform (maculopapular) eruptions, and bullous pemphigoid eruptions.^7-25,27-30

According to the advisors, the management of cirAEs starts with patient education on the occurrence of cirAEs, preventive measures, and skincare using gentle cleansers, moisturizers, and sunscreen started before ICIs treatment begins and ongoing during survival as part of the lifestyle.^9-25

Diagnosis of cirAEs

When diagnosing the cirAEs, other etiologies such as an infection, an effect of other agents, or other skin conditions should be ruled out.^8-11 

Biopsies play a role in accurately diagnosing the cirAEs when morphology is not clear. Histopathologically, cirAEs can be categorized into four broad groups, group 1: Inflammatory skin disorders, which reflect acute, subacute, or chronic inflammation of various patterns associated with variable epidermal changes, including psoriasiform or lichenoid interface chronic dermatitis.^16,50-53 Group 2: ICIs-related bullous skin lesions such as bullous pemphigoid or dermatitis herpetiformis, group 3: Keratinocyte alteration—Grover’s disease⁵⁴/acantholytic dyskeratosis, and group 4: Immune-reaction mediated by alteration of melanocytes such as regression of nevi, tumoural melanosis, and vitiligo.^29,36,48-52 For this review, we will only be focusing on the selected cirAEs.

When assessing the severity of cirAEs, grading systems’ trial limitations need to be considered.⁹ The Common Terminology Criteria for Adverse Events (CTCAE) classification is typically used; however, in the case of clinical trials, clinicians should be cognisant of the version the trial is using as different versions of CTCAE have different definitions and categorizations.²⁶

A general approach to prevention or reduction of cirAEs as well as initial management of the previously published CaSMO algorithm is displayed (Figure 2) for reference.³⁸  

Isolated Pruritus

Immunotherapy-related isolated pruritus occurs frequently and has a significant impact on QoL (Figure 3).^{7-25,31,46,55-57}  Diagnostic criteria for pruritus have been described as core symptoms, including duration of pruritus (more than six weeks) and a history of signs of scratching.^63,64 Associated criteria comprise a range of clinical manifestations, symptoms, functions, and emotions. The function includes the extent of impaired QoL, sleep loss, and days of absence from work. Emotions include possible psychological reactions such as, depression, anxiety, anger, and helplessness.⁶⁴

Isolated pruritus should be a diagnosis of exclusion once other causes such as pre-bullous pemphigoid, bites, or other drug reactions are ruled out.

A stepwise approach includes starting with over-the-counter topical agents, topical prescription agents, systemic drugs, and phototherapy.^63,64 General principles before starting topical and/or systemic treatment comprise skincare using gentle cleansers and moisturizers, especially in the presence of xerosis.^63,48

The CaSMO algorithm educates on general measures such as avoiding skin irritants, scented products, temperature extremes, sun, and the use of sun-protective clothing (e.g., brim hats and sunglasses). The information should be provided before immunotherapy starts, and this is especially important for isolated pruritus.³⁸ The daily skincare regimen should be reinforced with emphasis on gentle cleansers, skin moisturization, and sun protection – similar counseling to a patient with atopic dermatitis.^37,38,47  

A prurigo nodularis 4-tier treatment ladder⁶⁴ addresses neutral and immunologic mechanisms that may be applicable to ICIs-induced pruritus.⁶⁴ Immunologic mechanisms are more likely to be the underlying mechanism in ICIs-induced pruritus. Patients can enter the treatment ladder at any tier and move up or down the ladder based on their clinical presentation.⁶⁴  Immunologic tier 1 is more likely mechanisms can be treated with TCS, TCI, or topical calcipotriol.⁶⁴  Moisturizers, including antipruritics such as pramoxine 1% or formulations with menthol or camphor, may be used as an adjunct therapy.⁶⁴ 

For tier 2 neural mechanisms of pruritus medications include selective nor­epinephrine reuptake inhibitors (SNRIs) (i.e., mirtazapine) and gabapentinoids (gabapentin and pregabalin), which have antipru­ritic properties.^63,64  Second-generation histamine H1 receptor antagonists were shown to be effective and safe for patients receiving ICIs.⁶⁴ 

Additional second-line systemic therapies such as neurokinin 1 inhibitors (i.e., aprepitant) and inhibi­tors of interleukins (ILs) 4, 13 may be considered for the tier 3 immunologic mechanisms approach.⁶⁴ When evaluating the need for systemic or topical treatment, possible interactions with cancer therapy are assessed together with concomitant conditions and cirAEs.^{9-11,15,16,23,24 37,38,47}

Clinicians should take caution using systemic steroids and immunomodulators for patients receiving cancer treatment with ICIs (Table 2).^9-11

Table 2: Isolated pruritus

Psoriasiform Eruptions

T helper (Th) cells producing interleukin (IL)-17, IL-22, and tumor necrosis factor (TNF) drive the pathogenesis of psoriasis by orchestrating inflammation in the skin triggering proliferation of keratinocytes and endothelial cells.⁶⁵ Besides Th17 cells, other immune cells that are capable of producing IL-17-associated cytokines participate in psoriatic inflammation.^66-70  ICIs are thought to be driven through the TH17 pathway, and this may have implications on the development of psoriasis but also on the use of systemic psoriasis medications.^64,65,71,72

Immunotherapy with anti-PD1 and anti-PDL1 can exacerbate psoriasis, although more severe flares were noted in patients treated with durvalumab.^65-68,70,71

A personal or family history of psoriasis is a significant risk factor that should be identified before starting immunotherapy.^65,66,68 These patients require regular skin monitoring enabling early diagnosis and treatment of psoriatic exacerbations.^65,66,68 Prompt diagnosis can prevent a severe impact on QoL of this cirAE that may compromise therapeutic protocols and final cancer prognosis (Figure 4).^53,65,66 A skin biopsy to confirm the diagnosis, although not required, includes parakeratosis, hypogranulosis, regular acanthosis, suprapapillary plate thinning, and neutrophils at various layers of the epidermis.^68,70

Psoriasiform cirAEs can affect skin, nails, and joints and significantly impact QOL.^65-71 Psoriasis can be associated with arthritis as patients have a greater-than-expected incidence of psoriatic arthritis when it occurs as a cirAE of cancer treatment.^33,65,66 The choice of therapy takes many factors into account, including the extent and area of involvement, lifestyle, other health issues, and medications. First-line treatments include topical treatment with TCS, TCI, calcitriol, or a combina­tion of a super potent TCS with calcipotriol or tazarotene can be given.^65-71  For recalcitrant cases, consider adjuvant narrowband ultraviolet B therapy or oral treatment such as systemic retinoids [acitretin] or apremilast.^72-75  Although there is no direct evidence in ICIs treated cancer patients, methotrexate is immunosuppressive and may reduce the therapeutic effect of ICIs, similar to systemic steroids that have been shown to reduce RFS and OS.^32,33,35

Acitretin or apremilast is preferred over methotrexate; however, there is an absence of data for apremilast on the effect it may have on the anticancer treatment.^68-75  If the lesions persist, treatment with biologics may be required to treat psoriasiform cirAEs. IL-23 agents (gulselkumab, risankizumab, tildrakizumab) are considered most targeted and have the least direct evidence of immunosuppression (e.g. infection and TB reactivation). However, the risk/benefit needs to be considered before starting treatment with biologics (Table 3).^76-86

Lichen Planus

Immunotherapy-induced lichen planus is a pruritic, papulosquamous disease that can affect skin, hair, and nails (Figure 5). Treatment is required, especially if pruritic when it can severely impact QoL.^{7-19,27,33,46,63,77,78} When examining the patient exclude guttate psoriasis, mucositis, and bullous disease. Specific investigations include a detailed medical history and medication use, liver function tests including hepatitis C status, and, if required, a skin biopsy.⁷⁹

Pruritus may be treated with second-generation histamine H1 receptor antagonists (e.g., blistane, rupatadine, cetirizine and fexofendadine).^63,64,79 A retrospective analysis of clinical data investigating if commonly used medications might influence responses to checkpoint inhibitors. The researchers found that concurrent use of second-generation histamine H1 receptor antagonists correlated with significantly improved survival outcomes in those with melanoma or lung cancer. In addition, the antihistamine was effective for treating pruritus in cirAEs.^63,64,79 The choice of therapy takes many factors into account, including the extent and area of involvement, other health issues, and medications.^{8-11,67-69,78,80} First-line treatment includes moisturization and sun avoidance, antihistamines, TCS, and TCI.^80,81 Other second-line treatments include oral retinoids (acitretin), apremilast, sulfasalazine, metronidazole, hydroxychloroquine (especially for scalp or presentation with arthritis).⁸⁰ Additionally, narrowband or broadband UVB or PUVA may be used. Treatment with cyclosporine should be avoided as it may exert effects on the immune system (Table 4).^25,31,78

Table 4: Lichen planus

Eczematous Eruptions

Eczematous eruptions (EE) are associated with altered immune function, epidermal barrier dysfunction, genetic and environmental factors, and poorly understood interaction between these factors.^82-85 EE presents clinically as relapsing erythematous and pruritic patches of skin with varying severity (Figure 6).^9-11,82-85  Skin biopsies may be taken if the condition is extensive or not responding to therapy or if the diagnosis is in doubt.^9-11 Canadian and US guidelines for topical treatment of atopic dermatitis include education and avoiding triggers, routine skincare with gentle cleansers and moisturizers, and EE management foundation regardless of disease severity and prescription treatment.^82,83 Conventional moisturizers contain occlusives, humectants, and emulsions. Newer moisturizers designed to restore skin barrier defects include distinct ratios of lipids that resemble physiological compositions.^{36,38,47,82,83} If EE is not controlled with a moisturizer alone, TCS, TCI, or crisaborole ointment, an anti-inflammatory inhibitor of PDE4, is recommended while continuing skincare.^9-11,82-86   Treatment with crisaborole ointment achieved early sustained control of atopic dermatitis flares (reduced pruritus, erythema, exudation, excoriation, induration/papulation, and lichenification).^84,85  The topical PDE4 inhibitor offered a safe alternative to TCS and TCI.^84,85

For those not adequately controlled with topical treatment, nbUVB may be considered.^82,83 Dupilumab is a humanized monoclonal antibody against the shared alpha subunit of IL-4 and IL-13 receptors, blocking these cytokines commonly found in atopic dermatitis-affected skin. The use of dupilumab may be considered for extensive, moderate-to-severe EE. Two large, long-term RCTs demonstrated its efficacy and safety.^{9-11,82,83,86}  

Another option is tralokinumab (IL-13 inhibitor) which was shown to be effective and safe for the treatment of severe atopic dermatitis.⁸⁷

Treatment with the biologic is preferred to methotrexate which is an immunosuppressive and may reduce the anticancer effect.^9-11 TCS, TCI, and crisaborole can be used with any systemic treatment to address an EE flare (Table 5).^82-85,93

Morbilliform (maculopapular) Eruptions

These cirAEs may present as pruritic, nontender, erythematous papular, and macular eruptions on various body locations.^37,38,46,47 Physical examination focusing on the morphology and the distribution, starting on the trunk and then spreading to limbs, of the presented morbilliform eruptions is required to distinguish between the various cirAEs (Figure 7).^37,38,46,47 Laboratory tests may be needed and include a complete blood count, electrolytes, renal and liver function, and inflammatory markers.^37,38,46,47 Peripheral blood eosinophilia (≥500 eosinophils/microL) may be caused by numerous conditions, including allergic, infectious, inflammatory, and neoplastic disorders (Table 6).^37,38,46,47  Mild to moderate conditions may be treated with general skin care measures, TCS, TCI, and oral histamine H1 receptor antagonists to reduce pruritus.^63,64,94 Generally, this condition can be managed with aggressive topical treatment; however, for very severe and symptomatic cases, ICIs-treatment may be held, and a short course of systemic corticosteroids may be indicated.⁹⁴ 

Table 6: Morbilliform eruptions

cirAE BP can occur at any time, including after discontinuation of ICI. The onset to developing BP is within days or weeks of ICI exposure or may be delayed several months after starting ICI.³¹ Upon diagnosis ICIs is to be held and may require permanent discontinuation.^3,15,46 In milder cases, aggressive topical treatments with class I TCS may be as effective as systemic steroids.⁹²  cirAE BP may require systemic treatment and temporary, if not permanent, cessation of immunotherapy.^3,15,46 Systemic corticosteroids may be used the achieve control quickly while waiting for steroid-sparing treatments to take effect.^88,90-92 Non-immunosuppressive systemic treatment includes oral tetracycline-class antibiotics combined with oral niacinamide 500 mg twice a day, omalizumab, IVIg, and dupilumab.^31,88,90-92 However, steroid-sparing agents that are immunosuppressive may be required in order to control BP ongoing, including methotrexate, mycophenolate mofetil or rituximab.⁹¹ While rituximab may be immunosuppressive, it works on B-cells and may not hinder the T-cell activation from ICIs. In patients with cirAE BP, obtaining disease control as quickly as possible is ideal not only for improved QoL, and decreased morbidity but also if treatment is to be reinitiated (Table 7).^93,95

Table 7: Bullous eruptions

Limitations

The details provided on the mode of action of ICIs were limited to what is clinically relevant for this primer on cirAEs. Clinical studies on prescription medications and skin care for cirAEs frequently are case reports, case series, or have small sample sizes. For this reason, grading the evidence resulting from the literature searches was irrelevant. Therefore, recommendations given by the CaSMO project advisers are based on information from the guidelines, algorithms, consensus papers, and systematic reviews coupled with their clinical experience and resulting from discussions. More work is required to identify the best practice evidence-based management of cirAEs.

Summary and Conclusions

Immunotherapy for cancer patients is fast-developing into the standard of care for many malignancies. Although many publications are available on cirAEs, publications on the treatment using prescription medications and skincare are scarce.

The CaSMO practical primer focuses on isolated pruritus, psoriasiform eruptions, lichenoid eruptions, eczematous eruptions, and bullous pemphigoid. The practical primer addresses the need for physician awareness, patient education on the occurrence of cirAEs, prompt diagnosis, prevention, treatment, and ongoing skincare started before ICI.

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85. Paller AS, Tom WL, Lebwohl MG, et al. Efficacy and safety of crisaborole ointment, a novel, nonsteroidal phosphodiesterase 4 (PDE4) inhibitor for the topical treatment of atopic dermatitis (AD) in children and adults. J Am Acad Dermatol. 2016 Sep;75(3):494-503.e6
86. Simpson EL, Bieber T, Guttman-Yassky E, et al. Two phase 3 trials of Dupilumab versus placebo in atopic dermatitis. N Engl J Med. 2016;375(24):2335–2348
87. Wollenberg A, Blauvelt A, Guttman-Yassky E et al. Tralokinumab for moderate-to-severe atopic dermatitis: results from two 52-week, randomized, double-blind, multicentre, placebo-controlled phase III trials (ECZTRA 1 and ECZTRA 2). Br J Dermatol. 2021;184(3):437-449.
88. Fontecilla NM, Khanna T, Bayan CY, et al. Bullous pemphigoid associated with a new combination checkpoint inhibitor immunotherapy. J Drugs Dermatol 2019;18:103-104.
89. Kubicki SL, Welborn ME, Garg N, et al. Granulomatous dermatitis associated with ipilimumab therapy (ipilimumab associated granulomatous dermatitis). J Cutan Pathol 2018;45:636-638.
90. Siegel J, Totonchy M, Damsky W, et al: Bullous disorders associated with anti-PD-1 and anti-PD-L1 therapy: A retrospective analysis evaluating the clinical and histopathologic features, frequency, and impact on cancer therapy. J Am Acad Dermatol 2018;79:1081-1088.
91. Lopez AT, Khanna T, Antonov N, et al. A review of bullous pemphigoid associated with PD-1 and PD-L1 inhibitors. Int J Dermatol 2018;57:664-669.
92. Joly P, Roujeau JC, Benichou J et al. A comparison of oral and topical corticosteroids in patients with bullous pemphigoid. N Engl J Med 2002; 346:321-327
    DOI: 10.1056/NEJMoa011592
93. EsfahaniK, Elkrief A, Calabrese C, et al. Moving towards personalized treatments of immune-related adverse events. Nat Rev Clin Oncol 2020;17:504–15. doi:10.1038/s41571-020-0352-8
94. Fatima S, Veenstra J, Antonyan AS et al. Severe recalcitrant morbilliform eruption from dual immune checkpoint blockade. JAAD Case Rep 2018;4(6):593-595. PMID: 29955646
95. Aizman L, Nelson K, Sparks AD, et al. The influence of supportive oncodermatology interventions on patient quality of life: A Cross-Sectional survey. J Drugs Dermatol. 2020May 1;19(5):477-82.

Articles are indexed by drug names, trade names and disease terms. Bold entries refer to major references.

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Charles W Lynde MD, FRCPC¹, James Bergman MD, FRCPC², Loretta Fiorillo MD³, Lyn Guenther MD, FRCPC⁴, Marissa Joseph MD, FRCPC, FAAD⁵, Jill Keddy-Grant MD⁶, Ian Landells MD, FRCPC⁷, Danielle Marcoux MD, FRCPC⁸, Catherine McCuaig MD, FRCPC⁹, Michele Ramien MD¹⁰, Wingfield Rehmus MD MPH FAAD¹¹

Introduction

Atopic dermatitis (AD) is a lifelong pruritic, inflammatory skin disease associated with altered immune function and epidermal barrier dysfunction.^1-3 The chronic and recurring cyclic waxing and waning nature of AD leads the patient to treatment fatigue and imposes a significant burden on both the patients’ and caregivers’ quality of life (QoL).¹ AD frequently appears early in childhood and affects over 20% of children and up to 3.5% of adults.^2,3 Measurements of the prevalence of AD can differ, and this variability can be impacted by geographic location, population studied, and definition of AD used. A Canadian study showed that the adult prevalence of AD is up to 3.5% and that AD may be more prevalent among First Nations populations.² This research further revealed that men were less affected than women and that AD decreases with age. Additionally, the study noted that the severity of AD varies per region.² In many countries, the prevalence of AD is on the rise, especially in young children from developing lower-income countries in South East Asia and Latin America.⁴ Although the role of race and ethnicity in the pathophysiology of AD remains unclear, a higher incidence of AD was observed in Black American children (17.3%) compared to White children (10.4%).⁴

The pathophysiology includes skin barrier defects, inflammatory cytokines, and immune abnormalities. ADs’ etiology is multifactorial and involves an incompletely understood interaction between genetic factors, immune system dysfunction, skin barrier disorders, genetic and environmental stressors.^5,6 Most of the patients with AD have mild disease; however, 10% – 20% of children with AD are categorized as severe, and these rates are slightly higher in adults.²

There is a need for a variety of therapeutics targeted to different levels of severity.^6,7 A treatment paradigm that recognizes that patients may oscillate between degrees of severity and integrates topical and systemic therapies may align more closely with clinical reality.^8,9 AD treatment is often challenging due to the disease itself, treatment fatigue, and patient/caregiver concerns. Patients and caregivers frequently have concerns about medication safety and adverse events (AEs) as well as the long-term use of topical corticosteroids (TCS) or topical calcineurin inhibitors (TCI).⁹ Crisaborole ointment is an effective and safe alternative to TCS and TCI.⁹ Sharing best clinical practice standards, addressing challenges in treatment application, and methods to improve patient adherence to therapy may improve treatment results.⁹

This paper aims to review best clinical practices in treating AD patients, explore optimal use of crisaborole in mild to moderate disease, and provide expert guidance for the real-world use of crisaborole ointment to improve patient outcomes. This papers’ target audience is general practitioners, pediatricians, pediatric dermatologists, and dermatologists who treat patients with AD.

Methods

The project used a modified Delphi communication technique for interactive decision-making for medical projects, adapted from face-to-face meetings to suit a virtual platform.^10-12 The meeting was virtually convened on May 8, 2021, and the expert panel consisted of eleven dermatologists, including nine pediatric dermatologists from diverse geographical regions within Canada, who commonly treat patients with AD. In preparation for the meeting, a literature review surrounding crisaborole for the treatment of mild-moderate AD was conducted, and the panel members were surveyed regarding the use of crisaborole ointment for the treatment of AD.

The literature review and the pre-meeting survey results were presented at the virtual meeting. During the meeting, the experts were divided into three breakout groups to discuss and adopt draft recommendations for the real-world use of crisaborole ointment that were prepared from the literature searches by CWL and AA. The three groups presented their adapted versions of the recommendations to the larger group following the breakout session. The adapted recommendations were then collated and edited if necessary. The panel then voted and adopted the recommendations using evidence coupled with expert opinion based on the clinical experience of the advisors. The meeting summary and subsequent review of the manuscript were performed online (Figure 1).

Literature Review

Searches for English-language literature [2015– 2020] took place on April 14, 2021, on PubMed and Google Scholar as a secondary source. The data gathered by the literature review prioritized clinical studies published on the use of crisaborole, articles describing the current best practice in AD, and the most recent clinical guidelines, consensus papers and, algorithms. Excluded were duplications, articles of insufficient quality [small sample size, flawed methodology], and the most recent reviews were used in the case of review articles.

The searches yielded sixty-two papers deemed clinically relevant to current best practices of crisaborole use in AD. After removing duplicates and articles of insufficient quality, thirty publications remained: Four on epidemiology, ten reviews, three consensus papers and algorithms, four guidelines, five clinical studies, and four systematic reviews, meta-analyses, or posthoc analyses.

Results

The literature review indicated that the guidelines, algorithms, and consensus papers for topical AD treatment had not changed significantly over the past decade apart from adding crisaborole ointment and removing the black box for topical calcineurin inhibitor (TCI) treatment.^{7-9, 13-21}

A consensus paper and algorithm that explored the need for practical solutions to improve AD care was developed and published by the authors’ panel.⁸ The consensus statements and algorithm for topical treatment and maintenance of AD were integrated into the panels’ recommendations presented in this publication.

The DERMA (D: Diagnosis/Distribution; E: Education/Emollients; R: Red/Itchy; M: Medication/Maintenance; A: Assessment /Adherence) AD Algorithm targets a broad base of health care professionals treating patients with AD. The consensus statements and DERMA AD algorithm for topical treatment and maintenance of AD reflected current practice and were integrated into the panels’ recommendations (Figure 2).

Clinical Evidence of Crisaborole

Crisaborole is a small molecule, anti-inflammatory nonsteroidal PDE4-I inhibitor for the treatment of AD, which has demonstrated safety and efficacy in patients with mild-to-moderate AD.^22-30 Two percent crisaborole ointment was first approved by the American Food and Drug Administration (FDA) in December 2016 and then in 2018 by Health Canada for mild-to-moderate AD patients aged 2 years and over and in March 2020 (USA) and May 2021 (Canada) for patients aged 3 months and over.²⁵

The efficacy and safety studies on crisaborole used various clinical assessment scales such as Investigator Static Global Assessment (ISGA), Atopic Dermatitis Severity Index (ADSI), Eczema Area, and Severity Index (EASI) score, and Patient-Oriented Eczema Measure (POEM).

A randomized, double-blind, intra-patient controlled study (for the first 14 days) was continued as an open-label study applying crisaborole to all lesions. The study, including 40 patients of 18 years-old and older, demonstrated significant changes from baseline in crisaborole-treated lesions, ISGA, and pruritus NRS improvement from day fifteen assessment onwards.²³ The study also showed normalization of the genomic skin profile (approximated normal skin), inhibition of inflammatory genes known to be induced through degradation of cAMP by PDE4, and reduction in epidermal hyperplasia and TEWL.²³

The safety and efficacy of crisaborole treatment over 28 days were shown in two identical randomized, double-blind, vehicle-controlled studies including 1,522 patients with mild-to-moderate AD of 2 years and over.²² Significantly more patients treated with crisaborole than vehicle reached the primary endpoint (ISGA: clear, almost clear) than those treated with the vehicle at day 29 assessment.²² A long-term, open-label, single-arm 48 weeks safety study that included 517 patients of 2 years and over showed similar safety results as in a previous study that included adult AD patients.^22,24 In the long-term open-label study, nine patients (1.7%) withdrew due to AEs such as a stinging sensation after applying the ointment.²⁴ Another phase four open-label, single-arm study on 137 infants aged 3 months to less than 24 months of age demonstrated that crisaborole is safe and effective. ISGA of clear or almost clear was achieved at day 29 assessment by 30.2% of patients.²⁵ The study further indicated that improvements exceeded the minimal clinically significant difference in total POEM score at day eight and day twenty-nine.²⁵ The POEM subscale data further revealed improved sleep and pruritus, markedly improving patients’ and their caregivers’ quality of life.²⁵ Crisaborole yielded a rapid and statistically significant reduction in pruritus within four days.^26-28 Notably, in two vehicle-controlled studies, the vehicle effect on pruritus was considerable.^26,28

A pooled analysis of four studies of mild-to-moderate AD patients demonstrated efficacy and local tolerability of crisaborole treatment. After crisaborole use, most patients had mild to no pruritus from the first assessment through the remainder of treatment.²⁷

In a further study, treatment with crisaborole resulted in a marked improvement in QoL for patients and their parents, caregivers, and families.²⁸

A post hoc analysis of 2 phase 3 studies showed the effectiveness of crisaborole compared to the vehicle in significantly alleviating mild-to-moderate AD severity (per ADSI), and percentage of body surface area (%BSA) affected.²⁹

Finally, a systematic literature review and network meta-analysis comparing efficacy and safety profiles of crisaborole ointment, 2%, versus other topical treatments for mild-to-moderate AD showed crisaborole was superior to vehicle and pimecrolimus 1% cream, and comparable to tacrolimus, 0.1% or 0.03% ointments, concerning ISGA 0/1 at 28-42 days.³⁰ Additionally, the systematic review showed that the AEs rates for application site burning/stinging were much higher for TCIs than for crisaborole.³⁰ The studies included different patients, and endpoints varied, so comparative assessment of medications from this meta-analysis is difficult. Head to head comparative studies are needed to see objective scientifically-grounded efficacy comparison.

Crisaborole works better for mild than moderate disease, where it provides a faster reduction of pruritus and other AD symptoms relieve.^9,25-30 Crisaborole is not typically used with TCI due to potential irritation, but the combination may be suitable for steroid-phobic patients and those at high risk of sequelae.⁹

It is advisable to avoid crisaborole application on significantly flared skin due to possible irritation. Crisaborole ointment can be beneficial for dermatitis of the hands and feet due to the potential for deeper penetration into inflamed, thicker lichenified skin as a result of the smaller molecular size of crisaborole. There appears to be less irritation of the hands and feet, and the good safety profile of crisaborole justifies application in infants and children.^9,25-30

Statements and Recommendations

Statement 1: Atopic dermatitis (AD) is a lifelong inflammatory skin condition associated with epidermal barrier dysfunction and altered immune function. When AD is not controlled by behavioral measures such as skincare and avoidance of triggers, treatments such as TCS, TCI, and more recently, PDE4-I should be considered. It is important to use topical agents in conjunction with moisturizers and gentle cleansers.

The complex multifactorial pathogenesis of AD includes genetic and environmental factors.⁵ The skin barrier in AD is dysfunctional, and this defective skin barrier leads to water loss from the skin and the ingress of irritants, pathogens and allergens resulting in further inflammation.⁷ As the dysfunctional barrier at baseline is further disrupted, an inflammatory immune response is upregulated, which further disrupts the barrier leading to a feedback loop.^6,31,5,6

AD presents clinically as recurrent scaly erythematous and pruritic papules and plaques of skin with varying severity. This morphology, in addition to pruritus and family history of atopy, are important diagnostic criteria.^7,32 Specific signs of AD include oozing, scaling, crusting, erythema, edema, and lichenification, which, together with the body surface area involved and the impairment of daily activities, help determine AD severity (Figure 3-5).
Most patients with AD present with mild disease and can be adequately treated with frequent moisturization and topical therapy such as TCS, TCI, or crisaborole.^{3,5,7,8,12-21}

Educating patients and caregivers about the condition, avoiding triggers, and daily skincare regime, including gentle cleansers and moisturizers, is a vital part of the approach.^{7-9, 13-21}

AD is a chronic disease, and as a result, adherence to therapy is a major obstacle. Education and patient support and can improve adherence and, in turn, outcomes. It is important to remember that AD education is not a one-and-done phenomenon. Ongoing reinforcement of the treatment plan and goals is needed. Clinicians need to explain the condition, the rationale for treatment, optimal treatment use, and demonstrate the application process in their office.^8,9 During the detailed conversation, solicit the patients’ or caregivers’ input and questions to enable their active role in the process.⁹ This will help manage expectations, adherence to treatment, and maintenance of the lifelong chronic disease.⁹ Actions to improve patient adherence with treatment include detailed but easy to follow information and options to revisit the information by reading materials or trusted websites (Box 1).^8,9,15,19

Box 1: Patient and caregivers information and education about crisaborole

Statement 2: Crisaborole, 1% ointment, is a nonsteroidal anti-inflammatory PDE4-I with demonstrated efficacy in patients aged three months and older with mild to moderate AD. It is a well-tolerated alternative to TCS or TCI and can be used on any body site. It may be especially beneficial for:

• Sensitive areas prone to thinning from TCS such as the face, intertriginous areas, and genitals
• Hand, feet, palms, and soles, where the small molecular size may allow potential deeper penetration

A previous publication by the panel reviewed various cases that reflect real-world clinical use of crisaborole aimed to clarify its optimal use as monotherapy, combination therapy, sequential therapy, and maintenance therapy.⁹ Crisaborole can provide a good and safe alternative to TCS and TCI, such as in cases of steroid or TCI avoidance, and can be used in mild-to-moderate AD patients from 3 months of age upwards.²⁵

The case studies discussed in the article suggested that crisaborole treatment was effective and well-tolerated for pediatric AD of the face, hands, and feet of infants, toddlers, young children, and adults where therapy with TCS or TCI had failed.⁹ One of the cases was a 5-year-old boy with moderate-to-severe AD of his hands that was painful and severely impacting daily activities, such as playing and interacting with other children. After eight weeks of crisaborole use, his hand palms and wrists involvement had almost entirely cleared.⁹

The advisors recommend that the smaller molecular size of crisaborole may allow better penetration into the skin to the site of inflammation.⁹ The advisors also indicated that there might be a cumulative effect of adding crisaborole for hands and feet that can benefit from its optimal penetration as part of a combination regimen with TCS and TCI in moderate-to-severe AD cases.⁹

Statement 3: Crisaborole may be used as a first-line topical agent and is also a good choice when previous treatment has yielded suboptimal results when TCS side effects constitute a significant concern, and in the case of TCS/TCI phobia.

TCS and TCI hesitancy exists among all cultures and likely contribute to AD treatment failure.³³ Widely available biased unreliable, and inaccurate sources of information about eczema and topical therapies such as TCS and TCI are not helpful for AD patients and hinder physicians ability to educate and treat appropriately.³³ Clinicians must inquire about and if present must thoroughly discuss the patients and caregivers’ concerns about TCS and TCI and emphasize that these treatments are vital and, if used appropriately, safe and effective.^{5,7,8,9,12-21} Providing the patient with trusted websites can give balanced information, thus addressing the issues that are adding to patients concerns, especially in those with TCS and TCI phobia.^15,19

If patients or caregivers continue to have safety concerns surrounding TCS/TCI treatment, then crisaborole can offer a safe alternative even in infants as young as three months of age.²⁵ In this situation, offering a safe and effective alternative to TCS or TCI may improve treatment adherence and patient outcomes.⁹

Statement 4: When starting topical therapies such as crisaborole, consider the following:

• Test the patients’ tolerability with a sample before a prescription to determine the degree of stinging
• Avoid its initial use on severely inflamed or open areas of skin
• Limit its use to areas less likely to sting/burn
• Use the product in combination with a refrigerated moisturizer

The recommendations are supported by the advisors’ clinical experience⁹, a post hoc analysis of 2 phase 3 studies²⁹, and a systematic literature review comparing efficacy and safety profiles of crisaborole and other topical treatments in mild-to-moderate AD.³⁰ Crisaborole is used in mild-to-moderate AD, but it is best to avoid application on severely inflamed and open areas if possible to minimize stinging.^29,30

Testing the patients’ tolerability in-office before prescribing crisaborole provides an opportunity to teach the patient about the appropriate application of the medication and identifies the uncommon patient who has more prominent stinging and thus may not tolerate the medication. The application also helps to identify the patient who has mild discomfort. Proper education and guidance can minimize the symptoms and allow then to get past the short-term symptom. Application in the office and identifying these subgroups will instill greater confidence in the medication and make it more likely that the prescription will be filled and utilized rather than abandoned after one application.

Improved knowledge about the central roles a defective skin barrier and dry skin may play in AD increasingly recognizes the benefits of daily and ongoing use of mild cleansers and moisturizers.³⁴ The use of a gentle cleanser that employs advanced vehicles with a near-physiologic pH (4.0–6.0) may help maintain skin barrier function by optimizing skin surface pH levels.³⁴ Utilizing moisturizers to optimize the barrier decreases water loss, decreases inflammation, and improves the skin’s barrier and natural moisturizing factors. Moisturizers that contain skin lipids such as ceramides have shown benefits over standard emollients when used for AD patients.³⁵

In an algorithm for South and East Asian AD patients, moisturizers were included as a standard measure when using topical treatments for AD, such as pimecrolimus.³⁶ A refrigerated moisturizer used in combination with crisaborole ointment may prevent irritation, burning, or stinging.⁹

Statement 5: TCS, TCIs, and PDE4-I may induce application site pain such as burning and stinging. Information and education on measures to prevent or treat these side-effects, such as testing/limiting application sites and concomitant use of a refrigerated moisturizer, can help optimize results and decrease skin irritation.

Few AEs such as irritation, burning, and stinging were reported in clinical studies using crisaborole but seem to be occurring more frequently in clinical practice.^16,9

Clinical trials report stinging or burning occurring in up to 8%, but the symptoms are usually transient, and 1.7% of patients withdrew due to these symptoms. In practice, clinicians have anecdotally noted that the rate of stinging seems to be greater than that reported in clinical trials, but generally, the stinging is mild and transient.^16,9 Topical medications can sting due to the stabilizers and preservatives in the vehicle cream or due to the medication itself. TCIs can sting, and this stinging is often correlated to the degree of inflammation in the area. Clinicians often apply TCS initially to calm down the AD, after which the TCI is better tolerated. Whether this technique applies to crisaborole is not clear but should be answered by future reports/ studies.^8,9

Before starting crisaborole therapy, inform and educate the patient and caregiver on measures that may prevent or quickly resolve irritation, burning, or stinging if it occurs.⁹ Best practice tips of the panel include the use of crisaborole with daily skincare, such as a gentle cleanser and a refrigerated moisturizer.⁹ Apply a patient age-appropriate regimen and patient education.⁹ Identifying patients prone to skin irritation may benefit from an in-office trial with a sample before prescribing the ointment.

Survey Results

A pre-meeting survey was conducted among the panel to share best practice standards and clinical pearls they use in prescribing crisaborole to mild-to-moderate AD patients. All eleven advisors completed the survey. Demographics, number of visits of AD patients, the severity of AD, and treatment are shown in Table 1. When asked: If Crisaborole is not your first choice, indicate why not? stinging (63% [7]), burning (40% [4]) and costs (91% [10]) were frequently mentioned. Six physicians also answered crisaborole was not used for other reasons, which included: Lack of payer coverage, Need to be off-flare to initiate the treatment to get a good response, It is not as effective and does not work as quickly as TCS or TCI, Other medications are effective and more readily available and with which there is more clinical experience. The advisors noted to specifically use crisaborole for various body locations such as the face (72% [8]), hands (91% [10]), eyelids (55% [6]), intertriginous areas (63% [7]), genitals (63% [7]), and feet (81% [9]). According to the advisors, they hypothesize that the small molecular size of crisaborole appears to allow better penetration on areas with thicker skin.

Table 1: Pre-meeting survey results
N=11
Topical corticosteroid (TCS), atopic dermatitis (AD)

When asked the main reasons to prescribe crisaborole, all (100% [11]) answered that there is a need for a nonsteroidal alternative. Other answers included TCS phobia (91% [10]) and TCI phobia (63% [7]) and suboptimal results with previous therapy (63% [7]).

When stinging or burning occurred with crisaborole use, the advisors discontinued the treatment more frequently in children than adults. For preventing and managing AEs, the advisors provided education before starting crisaborole treatment. Some tested patients’ tolerability to the treatment in the office prior to a prescription to determine the degree of stinging. Further, they recommended measures to reduce stinging, such as concomitant use of a gentle cleanser and refrigerated moisturizer, cooling the ointment in the fridge, and concomitant TCS or TCI use (Figure 6). Finally, the advisors agreed to avoid the application of crisaborole on severely flaring skin.

When asked about the patients’ response to crisaborole treatment within four weeks, forty percent of responders noted that on average, 20-50% of patients had improved, and 50% of the panel noted an improvement in over 50% of their patients (Figure 7 and 8).

Limitations

Measures to reduce burning and stinging that may occur when using crisaborole were developed using the authors’ expert opinion and clinical experience, and further studies are needed to support the possible benefits of these measures.

Conclusions

The review explored best clinical practices of crisaborole for mild to moderate AD patients and provided expert guidance for the real-world use of crisaborole ointment.

Atopic dermatitis is a common chronic inflammatory disorder in which patients experience a waxing and waning disease state that is punctuated by episodes of flares. If their disease is quiescent, then the patient continues good skincare by utilizing moisturizers and avoiding irritants. Patients will escalate and add topical medications at the first sign of a flare. Since every patient has a distinct disease course, some patients may never be fully clear while others clear between episodes. Recognition that patients with AD have a disease that often varies in severity and location on their body allows physicians to choose the appropriate treatments based on their clinical experience. The physician needs to educate their patient to escalate therapy accordingly at the first sign of disease in order to prevent severe flares. An eczema treatment plan is a necessity to ensure a smooth transition of therapy from baseline to flare. For mild to moderate AD patients, three topical options can be prescribed to control inflammation. Traditionally these medications have been divided into first and second-line therapy. However, the expert panel believes that the choice of a specific agent should be decided by the clinician based on factors such as disease severity, location, physician experience with the product, cost, and patient preference.

Crisaborole is a nonsteroidal PDE4-I with demonstrated safety and efficacy in patients aged three months and older with mild to moderate AD. It is a well-tolerated alternative to TCS or TCI and can be used on any cutaneous non-mucosal body site. It may be especially beneficial for areas with thicker skin, such as hands and feet, possibly due to improved penetration to the site of inflammation as a result of its small molecular size. There are no concerning serious safety signals associated with crisaborole. Crisaborole does cause a burning sensation in 8% of patients, but this is usually transient and may be minimized by the concomitant application of cool moisturizers. Consideration of in-clinic test site application of crisaborole to high-risk individuals may help identify those at risk and allow patient education, which may decrease the side effect and in turn improve adherence and outcome.

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¹Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
²Department of Pediatrics, University of British Columbia, Vancouver, BC, Canada
³Department of Dermatology and Skin Science, University of British Columbia, Vancouver, BC, Canada

Conflict of interest:
Joseph Lam has served as an advisory board member for Bausch Health, Leo Pharma, Pfizer Canada and Sanofi-Genzyme.
He is on the speaker’s bureau for Pfizer Canada. He has received a research grant from the Eczema Society of Canada. Aryan Riahi has no conflicts to declare.

Abstract:
Atopic dermatitis (AD) is a chronic, relapsing, inflammatory condition marked by pruritus and traditionally treated with topical corticosteroids (TCS) and topical calcineurin inhibitors (TCI). Crisaborole 2% ointment (a topical phosphodiesterase-4 inhibitor) is a newer topical agent for the treatment of AD. Crisaborole is indicated for treating mild-to-moderate AD and evidence from phase 3 and phase 4 trials show that crisaborole is an effective agent with a well-tolerated side effect profile for children >2 years of age. The most common side effects are pain and paresthesia at the application site. Treatments with tolerable safety profiles such as crisaborole may provide an alternative to patients with TCS phobia. The role of crisaborole in AD therapy may become clearer as multiple phase 4 trials are currently underway and their results are poised to answer more questions, including its safety profile for patients as young as 3 months of age, potential use as a steroid-sparing agent, and direct comparisons to TCS and TCI, which are the current mainstay treatments of mild-to-moderate AD.

Key Words:
crisaborole, Eucrisa, atopic dermatitis, eczema, topical treatment, phosphodiesterase-4 inhibitor, corticosteroids

Introduction

Atopic dermatitis (AD) is a chronic, relapsing, and inflammatory condition affecting the skin. Clinical features include xerosis, oozing, crusting, and erythema. Pruritus is a hallmark manifestation of AD that can cause frequent scratching, leading to skin infections and lichenification.¹ The face, scalp and extensor surfaces are commonly involved in infancy, while there is prominent flexural involvement in older children and adults.² While some patients experience resolution by adolescence, others have symptoms that persist into adulthood.³ AD has been estimated to affect 15-30% of children and 10% of adults in industrialized nations.⁴ The economic burden of AD has been estimated to be $3.8 billion per year.⁵ Due to the chronic nature of AD and limitations of current available topical agents, especially for pediatric use, there remains an unmet need for novel AD therapies to address long-standing treatment gaps. Crisaborole 2% ointment (Eucrisa™) is a Health Canada and US FDA-approved topical phosphodiesterase-4 (PDE4) inhibitor for treating mild-to-moderate AD. Evidence from phase 3 and 4 trials demonstrate crisaborole is an effective agent with a well-tolerated side effect profile for children >2 years of age.⁶

Overview: Diagnosis and Pathogenesis

The diagnosis of AD is clinical. Skin biopsy and laboratory testing such as serum immunoglobulin E (IgE) levels are not routinely performed in the evaluation of suspected AD, but may be useful in ruling out other skin conditions.⁷ Adverse impacts from AD are wide ranging and include impairments to general health, quality of life, and mental health, with the financial cost of disease management posing a significant concern for patients and their families. Scratching may expose patients to secondary infections, which can exacerbate the severity of AD.⁸ The differential diagnosis for AD includes irritant or allergic contact dermatitis, serborrheic dermatitis, psoriasis, and scabies. Intractable, chronic itch is a hallmark of AD. Scratching may expose patients to secondary infections, which can exacerbate the disease severity.⁶

The pathogenesis of AD is determined by numerous factors including abnormalities in the skin barrier, a skewed T helper type 2 (Th2) immune response, impaired innate immunity, and changes in the resident microbial flora of the skin.⁹ The epidermis of patients with AD is prone to increased transepidermal water loss.¹⁰ The filaggrin (FLG) protein, which is produced by keratinocytes and encoded by the FLG gene, serves a critical role in skin barrier formation.¹¹ Patients with AD have lower levels of expression of skin barrier-related proteins including FLG-2, corneodesmosin, and enzymes necessary for skin hydration and water retention at the stratum corneum.¹² In addition to a barrier defect, the underlying immune system is also dysregulated in patients with AD. The innate immune response depends on toll-like receptors, which are stimulated by tissue damage and microorganisms, and enhance the strength of tight junctions to prevent allergen and microorganism penetration.¹³ Grouping patients with AD into one endotype may be overly simplistic. AD has a variety of endotypes depending on age groups, ethnicities, FLG mutations, and IgE levels.¹⁴ These include Asian versus European American, adults versus children, and presence or absence of family history of FLG mutations.¹⁴ Since increased Th2 cell levels are common across the spectrum of AD, targeting this factor should theoretically be therapeutic for all phenotypes of AD. However, phase 3 trials of dupilumab, an interleukin (IL)-4 and IL-13 blocker targeting the Th2-mediated pathway, was only able to reduce the Investigator’s Global Assessment score of patients down to 1 or 0 in 36-38% of cases.¹⁵ This suggests that other immune mediators outside of Th2 cells may be involved in the pathogenesis and treatment of AD.

Treatment Options for Atopic Dermatitis

The goals of treatment for AD are to achieve symptom reduction and prevent exacerbations. This approach is balanced with minimizing the risks of therapy. The mainstay therapy of AD is topical corticosteroids (TCS).¹⁶ An alternative to TCS is topical calcineurin inhibitors (TCI). Both treatments elicit potential side effects if used improperly. The face and skin folds are areas at high risk for atrophy with inappropriate use of TCS. High potency TCS also pose the risk of systemic toxicity, such as adrenal suppression in pediatric populations, especially if used under occlusion, e.g., diapered area.^17,18 TCI medications such as topical tacrolimus ointment and pimecrolimus cream do not carry the risk of skin atrophy, but may burn and sting on application. Patient education is needed as topical tacrolimus and pimecrolimus come with an FDA black box warning for increased risk of malignancies such as lymphoma.^19,20 Since the regulatory manadate to include the black box warning was institued in 2005, there has been mounting evidence to support the safe use of TCIs and the increased risk of malignancy remains theoretical. Prior to topical crisaborole, no new topical molecules have been approved to treat AD over the last 15 years.

Severe AD may warrant the use of ultraviolet-B (UVB) phototherapy or systemic immunosuppressant therapy such as cyclosporine, methotrexate, or mycophenolate mofetil when the patient is refractory to topical treatments.²¹ In 2019, both the FDA and Health Canada approved dupilumab for treating patients with AD >12 years of age who suffer from moderate-to-severe AD when topical therapies are ineffective or not advised.^22-24 Dupilumab is a fully human monoclonal antibody that binds to the IL-4 receptor and inhibits signaling of IL-4 and IL-13.²⁵

Crisaborole 2% is a topical PDE4 inhibitor indicated for the treatment of mild-to-moderate AD. Studies have shown that crisaborole 2% ointment improves AD signs such as exudation, excoriation, lichenification, and especially pruritus. Unlike TCS and TCI therapies, systemic exposure to crisaborole is limited.²⁶ The most common side effects are pain and paresthesia at the application site.²⁷

Crisaborole‘s Mechanism of Action

Crisaborole inhibits the action of PDE4. Pharmaceutical interest in phosphodiesterase enzymes, including crisaborole, was sparked by their role in nucleotide signaling pathways, leading to the development of specific novel inhibitors.²⁸ Elevated PDE4 enzyme levels have been associated with a chronic inflammatory state.²⁹ Since PDE4 is expressed by immune cells and keratinocytes, inhibition of PDE4 increases intracellular levels of cyclic adenosine monophosphate (cAMP) which inhibits the nuclear factor kappa B (NF-kB) pathway and the release of tumor necrosis factor (TNF)-alpha and pro-inflammatory cytokines that have a causal role in AD and psoriasis.²⁹

Crisaborole’s boron chemistry allows for formation of a low molecular weight molecule that penetrates human skin effectively.³⁰ Systemic exposure and risk of adverse effects from crisaborole is generally avoided due to the molecule’s rapid metabolism to inactive metabolites that do not affect cytokine release or the activity of PDE4.²⁹

Completed and Ongoing Studies of Crisaborole

Crisaborole’s safety profile and efficacy has been evaluated through 2 double-blind vehicle-controlled controlled phase 3 clinical trials. These studies assigned patients aged 2 years and older with mild or moderate AD as per Investigator’s Static Global Assessment (ISGA) scoring for treatment with either 2% crisaborole ointment or vehicle for 28 days. Results collected on day 29 demonstrated that 51.7% of patients receiving crisaborole had an ISGA of clear (0) compared to 40.6% of vehicle-treated patients (P = 0.05) and 48.5% of patients had ISGA of almost clear (1) compared to 29.7% of those treated with vehicle (P < 0.001).⁷

Two randomized, double-blind, vehicle controlled phase 3 studies with 759 and 763 participants demonstrated that crisaborole improves pruritus compared with vehicle (56.6% vs. 39.5%; P < 0.001) as early as day 2 of therapy (34.3% vs. 27.3%; P = 0.013).³¹

TCS are routinely used as therapy for flare-ups in AD.³² However, only short-term TCS use is recommended to minimize local and systemic adverse effects such as striae, telangiectasia, cutaneous atrophy, and acne.³³ As for TCI, both Health Canada and FDA initially advised against the use of long-term TCI therapy due to the unclear risk of malignancy.^19,20 Health Canada has subsequently removed the black box label for primecrolimus.³⁴ However, patients may continue to be apprehensive about using TCIs given their previous black box labeling. More research, including investigations on long-term maintenance, is needed to determine optimal topical treatment options for AD with favorable safety profiles. There is a phase 3 randomized, double-blind, vehicle-controlled study being conducted with 700 patients with mild-to-moderate AD.³⁵ Patients will receive crisaborole twice a day for a maximum of 8 weeks to identify responders, defined as ISGA score of 0 or 1 with 2-grade improvement from baseline or 50% improvement from baseline based on Eczema Area and Severity Index (EASI50) scoring. Non-responders will be discontinued after the 8-week run-in period. Maintenance treatment consists of once daily administration of crisaborole QD. Flares defined as ISGA ≥2 will be treated with twice daily crisaborole for up to 12 weeks. Completion of the trial is anticipated by July 2022.³⁵

The efficacy and safety profile of crisaborole is currently being investigated in phase 4 trials. A randomized, double-blind, vehicle-controlled study is evaluating the efficacy and safety of 3 different application rates of crisaborole ointment 2% in adults with mild-to-moderate AD.³⁶ Each patient will have 4 application areas and receive 1 of 4 treatments ranging from vehicle to 3 different application rates of crisaborole. Patients will be randomly assigned to treatment with topical crisaborole (application rates A, B, or C) or vehicle, once daily, for 2 weeks. The results of this study, with a projected completion of June 2020, may demonstrate whether the efficacy and safety of crisaborole is dose dependent. The results may be compared and contrasted with TCS use, which has a well-known dose dependent effect (e.g., anti-inflammatory effects at lower doses, immunosuppressive activity at higher doses) as well as dose dependent adverse effects (e.g., ecchymosis, parchment-like skin, and sleep disturbances).³⁶

Long-term topical treatment is often required for the management of a chronic inflammatory skin conditions like AD. Crisaborole’s long-term safety was evaluated in an open-label extension study of 517 patients with mild-to-moderate AD who used crisaborole for 48 additional weeks after the 28-day phase 3 study. The most frequently reported treatment related adverse effect (AE) were AD (3.1%), pain at the site of application (2.3%), and localized infection (1.2%).²⁷

The treatment options for patients under 2 years of age with AD are sparse. Pimecrolimus has recently been approved for infants as young as 3 months.³⁷ However, having a wider array of therapeutic strategies would be ideal for this demographic. A phase 4 multicenter, open-label, single arm investigation called the CrisADe CARE 1 study evaluated the safety, efficacy, and pharmacokinetics of crisaborole 2% ointment applied twice daily on 125 pediatric patients between 3-24 months of age.³⁸ These patients had extensive AD involving at least 5% of body surface area (BSA) except for the scalp. A total of 29.93% of patients reported non-serious AEs. The most common side effect was pyrexia (9.49%). The study found a total of 1 (0.73%) serious AE involving a febrile convulsion. The study did not comment on whether this AE was related to the use of crisaborole. No deaths occurred. This study is the first to evaluate the safety profile of crisaborole in children less than 24 months of age.

Crisaborole may have the potential of decreasing steroid use in patients with AD. Side effects of TCS can range from cutaneous atrophy to suppression of the hypothalamic-pituitary-axis.³⁹ Misunderstandings and steroid phobia can interfere with patient compliance, which in turn negatively affect disease control.⁴⁰ Currently, a proof-of-concept phase 4 clinical trial with 60 children between 2-18 years with mild-moderate AD is underway to determine whether crisaborole is an effective steroid reducing agent. The trial will be completed by November 2020.⁴¹ Similarly, a single-center observational prospective cohort study aimed to evaluate the efficacy and safety profile of crisaborole ointment 2% and a TCI versus crisaborole alone over 8 weeks. The study included participants aged 2-79 with mild-tomoderate AD and the projected completion was March 2020.⁴²

While high-quality phase 3 studies have demonstrated the efficacy of crisaborole compared to vehicle, head-to-head studies comparing crisaborole with TCS or TCI are needed to better define its role in the management of AD. A phase 4 multicenter, randomized, vehicle versus active (TCS and TCI) controlled study is being conducted on 600 patients with mild-to-moderate AD over 4 weeks to evaluate the safety and efficacy of crisaborole 2% ointment, crisaborole vehicle, TCS, and TCI applied BID in patients over 2 years of age.⁴³ Inclusion criteria include patients with AD involving at least 5% of BSA except for the scalp. The primary efficacy endpoint is change from the patient’s baseline in the EASI score by Day 29. The study will be completed by March 2021. This will be the first study to directly compare crisaborole to the current mainstay treatments of mild-to-moderate AD.

Conclusion

Crisaborole provides a novel and safe treatment option for mild-to-moderate AD. Crisaborole’s boron chemistry allows for formation of a low molecular weight molecule that penetrates human skin effectively but is inactivated and metabolized rapidly.³⁰ Crisaborole therapy has been shown to decrease pruritus, which disrupts the itch-scratch cycle that exacerbates signs of AD, improve quality of life, and decrease the risk of infection and scarring.⁴⁴ Adverse events related to crisaborole 2% are overall infrequent and range from mild-to-moderate in severity. Studies are currently underway to determine whether crisaborole can be used as long-term maintenance therapy for patients who respond to treatment. Furthermore, while crisaborole’s side effect profile is generally well tolerated, new head-to-head studies comparing crisaborole with TCS or TCI are underway to better define its role in the management of AD.

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