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.

¹Associate Professor, Department of Medicine, University of Toronto, Toronto, ON, Canada
²Clinical Assistant Professor, Department of Dermatology, University of British Columbia, Vancouver, BC, Canada
³Clinical Professor, Director of Pediatric Dermatology, University of Alberta, Edmonton, AB, Canada
⁴Professor, Western University, London, ON, Canada
⁵Assistant Professor, Department of Medicine, Department of Pediatrics, University of Toronto, Toronto, ON, Canada
⁶Assistant Professor, Department of Pediatrics and Child Health, University of Manitoba, Winnipeg, MB, Canada
⁷Division of Dermatology, Sainte-Justine University Medical Center; Clinical Professor in Pediatrics, University of Montreal, Montreal, QC, Canada
⁸Division of Dermatology, Sainte-Justine University Medical Center; Clinical Professor in Pediatrics, University of Montreal, Montreal, QC, Canada
⁹Clinical Associate Professor, Department of Pediatrics, University of Calgary, Calgary, AB, Canada

Funding:
This Supplement was developed using the Authors’ Expert Opinion, supported by an unrestricted Educational Grant from Pfizer Canada.
Use crisaborole ointment in off-label settings is left up to the discretion of the treating health care professional after careful clinical evaluation.

Abstract:
Background: Atopic dermatitis (AD) is associated with epidermal barrier dysfunction. The chronic skin condition presents clinically with pruritus and recurrent skin lesions. The psychosocial impact of the condition is severe for most patients and their families.
Crisaborole, a topical PDE4 inhibitor, has demonstrated efficacy in patients with mild-to-moderate AD.

Objectives: A diversity of cases are presented that reflect real-world clinical use of topical crisaborole ointment, as a mechanism to help optimize patient care.

Methods: Evidence from the literature coupled with the panels’ expert opinion, experiences and, key insights reflect the panels’ clinical use of topical crisaborole ointment for AD and irritant dermatitis (off-label use) and how patients can benefit from its use, i.e., “what experienced specialists are doing across Canada.”

Results: The panel treated and presented cases that report on crisaborole ointment used as monotherapy, combination therapy, sequential therapy, and maintenance therapy. The presented cases aim to illustrate the diversity of crisaborole use concerning age range, skin type/ethnicity, and body location. Each case presents a summary of the learning points.

Conclusions: The presented cases reflect the panels’ real-world clinical experience with crisaborole for the treated patients. The panel suggested that crisaborole ointment provides a good safe alternative to TCS and TCI. Treatment with the ointment should be avoided on severely flaring skin and for those that experience irritation, burning, or stinging while testing it on unaffected skin areas.

Key Words:
Atopic dermatitis, Real-world cases, Topical PDE-4 inhibitor

Introduction

Atopic dermatitis (AD) is a lifelong inflammatory skin condition associated with epidermal barrier dysfunction and altered immune function, presents clinically with recurrent episodes of pruritic erythematous papules and plaques.¹ AD usually starts in infancy, where it affects up to 20% of children in North America, and is also highly prevalent in adults.² Two-thirds of AD patients are reported to have mild disease, 26% moderate, and 7% severe AD disease.³ The majority of patients are treated by primary care physicians who primarily use topical anti-inflammatory therapy for their mild-to-moderate AD cases.^4-13

The psychosocial burden of AD on patients and their families is enormous.¹⁵ The inflammatory skin disease increases the risk of other immune-mediated inflammatory atopic disorders, such as asthma, allergic rhinitis and food allergies, as well as mental health disorders in some.^15,16

Patients with AD should use gentle cleansers and moisturizers that are balanced to the skin pH in addition to behavioural measures such as avoidance of irritants and triggers.

AD is a chronic relapsing disorder with periods of quiescence punctuated by intermittent flares. When AD flares then treatments such as topical corticosteroids (TCS), topical calcineurin inhibitors (TCI), and more recently, phosphodiesterase-4 (PDE4) inhibitors should be considered, while continuing skincare and measures to avoiding triggers of AD. TCS and TCI treatments are widely used as monotherapy in cases of mild-to-moderate AD or in combination with systemic treatments for more severe AD involvement. These treatment regimens are supported by clinical guidelines and clinical pathways worldwide and have an established safety record.^4-13 Crisaborole ointment (Eucrisa, Pfizer), a unique topical prescription option for AD, is a PDE4 inhibitor with demonstrated efficacy in patients aged two and older with mild to moderate AD.¹⁶

The presented real-world case-based approach explores the role topical crisaborole can play in the prevention, treatment and maintenance of AD and other inflammatory skin conditions, in clinical practice. The selected patient cases aim to outline a diversity of cases that reflect real-world use of topical crisaborole ointment for patients with AD and other skin conditions, either as monotherapy or in combination with other treatments. Any discussion concerning off-label use is considered an expert opinion only.

Methods

Aim of the Project

This current real-world case project was conceived as a mechanism to help optimize patient care by recognizing the role crisaborole ointment can play in the prevention, treatment and maintenance of AD. Additionally, the project explores where this therapeutic agent could be used in managing AD in patients who require a combination of therapies. The cases intend to illustrate the authors’ real-world clinical experience rather than reflect controlled clinical trial data. Evidence coupled with the expert opinion, experiences, key insights and recommendations is presented and discussed. Recommendations given by the panel reflect the use of topical crisaborole ointment for AD and how patients can potentially benefit from its use, i.e. “what experienced specialists are doing across Canada”. Any discussion concerning off-label use is considered an expert opinion only.

The target audience for this publication is physicians and other health-care professionals who treat patients with AD.

Steps in the Process

The five-step procedure included a) project definition and panel selection, b) collection of information and preparation of cases, c) meeting to select cases for the publication, d) literature review to support the cases, and e) creation, review, and finalization of the manuscript.¹⁷

Role of the Panel

An expert panel of eight dermatologists and pediatric dermatologists, selected to represent the diverse geographical regions within Canada, who commonly treat patients with AD, was convened on November 9, 2019, in Toronto, as part of the semiannual Dermatology Update conference. The panel members reported clinical cases of pediatric and adult patients who were suitable candidates for crisaborole ointment treatment.

The panel members discussed the cases in the light of the supporting literature, then decided which cases would be included in the publication. The publication was prepared and reviewed by the panel members.

Topical Treatment for Mild-To-Moderate AD

Avoidance of triggers of AD flares and education are the first steps in the prevention, treatment, and maintenance of AD.6

Skincare Using Gentle Cleansers and Moisturizers

Skincare using gentle cleansers and moisturizers remains the cornerstone of treatment for all severities of AD. Daily use of this skincare regimen is supported by established guidelines and clinical pathways.^4-13 Moisturizers play an important role in combating and controlling xerosis, decreasing epidermal water loss, and restoring epidermal barrier function.^6,10 Moisturizers should be liberally and frequently applied and can be used alone for mild disease or in combination with other therapies regardless of the severity of their AD. ^6,10

TCS and TCI

If avoidance of triggers and the use of a daily skincare regimen with gentle cleansers and moisturizers are not effective, topical anti-inflammatory agents, such as corticosteroids (TCSs) or calcineurin inhibitors (TCIs) are used twice a day until the lesions have cleared.^3-13 TCS is the first-line anti-inflammatory option, available in a variety of strengths from mild to potent and very potent.^6,11 Side effects such as skin atrophy, purpura, telangiectasia, striae, focal hypertrichosis, impaired wound healing, allergic contact dermatitis, and acneiform or rosacea-like eruptions on the face are very uncommon when TCS is used appropriately.⁶ Both patients’ and parents’ fear of TCS and steroid phobia should be discussed to improve adherence and avoid under-treatment.⁶

TCI’s are another safe and effective treatment option, however short-term side effects such as skin burning, and pruritus, especially when applied to acutely inflamed skin and cutaneous viral infections, may occur.⁶ Patients and parents should be informed about these potential side effects to avoid premature discontinuation of treatment.⁶ TCIs are therapeutic agents often used for mild AD on the face, neck, and folds, and used in prevention and TCS reduction elsewhere on the body.

Systemic Therapy

For patients affected by more severe AD, agents that target immune responses and inhibit T cells by targeting Th1, Th2, Th22, phosphodiesterase-4 (PDE4), IL-4, and IL-31 are available.¹⁸ Phototherapy and traditional systemic therapies, including methotrexate, cyclosporine, and mycophenolate mofetil, can also be used off-label in severe AD.

Crisaborole Ointment

Crisaborole (Eucrisa, Pfizer), a topical prescription option for AD, is a PDE4 inhibitor with demonstrated efficacy in patients aged two and older with mild to moderate AD.16 Two, multicenter phase III trials, demonstrated early sustained control of mild-to-moderate AD in patients aged over two years with crisaborole ointment use over twenty-eight days.¹⁶ When compared to the vehicle, treatment with the 2% crisaborole ointment showed reduced pruritus, AD severity, and other signs of AD (erythema, exudation, excoriation, induration/papulation, and lichenification), although clinicians have expressed concerns about stinging and burning on at application sites.^16,19

A multicenter extension study indicated that crisaborole ointment for up to fifty-two weeks is safe.¹⁷ The extension study reported an overall 10.2% rate of crisaborole treatment-related adverse events such as dermatitis (3.1%), application site pain, stinging, burning (2.3%), and application site infection (1.2%).³ These events were considered mild, and no one withdrew from the study due to these adverse events.

Less common potential side effects included skin irritation and hives or welts, which may be due to underlying atopy. Given the good tolerability and safety profile, crisaborole ointment makes for an alternative steroid-sparing topical option to TCS and TCI.¹⁶

Data Gathering of Real-World Cases on Crisaborole Ointment Use

The panel members used a template for their case studies, which asked the following questions:

• What are the cases and the impact of the condition?
• What are the treatment options, and what treatment(s) were previously used for this case
• Why might crisaborole ointment work in this case, where does it fit and what were the results of the treatment?
• Did any adverse events occur? If yes, describe.
• What (if any) are the special circumstances related to this particular case, and which lessons are learned?

Patient evaluations were at baseline (start) and at eight weeks (+/- 5 days) using physician reported skin condition (SCORing Atopic Dermatitis Clinical assessment [SCORAD] score.²¹ SCORAD recorded AD location and percentage area (A), Intensity (B): Redness, swelling, oozing/crusting, scratch marks, skin thickening, dryness [the intensity of each of the following signs is scored as none (0), mild (1), moderate (2) or severe (3)] and subjective symptoms (C) [Sleeplessness: 0 = no sleeplessness and 10 = the worst imaginable sleeplessness, Itch: 0 = no itch and 10 = the worst imaginable itch]). Total SCORAD is the sum of A, B, and C, minimum score = 0, maximum score = 103.21 The impact of the skin condition after treatment regime use and adverse events were recorded at baseline (start) and week 8 (+/- 5 days) (end).

Some of the physicians used quality of life for the participants 15 years or younger as assessed by Children’s Dermatology Life Quality Index (CDLQI). The minimum score is 0, and the maximum score is 30, the latter corresponds with the most severe impairment of quality of life. Other scores used were severity of itching as assessed by the Pruritus score determined using the Numerical Rating Scale (Minimum score is 0. The maximum score is 10, the latter corresponding to the most severe itching imaginable by the patient).

Selected Real-World Cases

The panel selected a total of eleven cases that reported on realworld use of crisaborole ointment as monotherapy, combination therapy, sequential therapy, maintenance therapy, preventive therapy, and its application in dermatitis beyond AD. (Table 1). The presented cases aim to illustrate the diversity of crisaborole use concerning age range, skin type/ethnicity, body location, the severity of AD, and reports of off-label use.

Case 1: A 4½-year old girl with AD since the first months of life, which had recently increased in severity. The moderate-tosevere condition involved multiple sites, including hands and feet. Previous treatment with various TCS formulations was unsuccessful. When crisaborole started, mometasone ointment was continued as needed on the lesions on her body. The rationale for starting topical 2% crisaborole ointment was the failure of previous treatments and a specific interest in improving the skin condition of her hands and feet. Her skin condition markedly improved over the eight week treatment period (Figure 1A-1J). No adverse events occurred, and the ointment was well tolerated even on the face.

Learning point: Crisaborole is a well-tolerated (even on the face) alternative for TCS and is effective on hands and feet.

Figure 1A – 1D

Figure 1E and 1F

Figure 1G and 1H

Figure 1I and 1G

Case 2: For four months, a 4-year-old boy had suffered from AD, primarily on the face, antecubital, and popliteal fossa. He had almost constant pruritus and open, erythematous skin. His interaction with other children was poor, and both the patient and parents had difficulty sleeping. Previous long-term TCS treatments lacked success. Moreover, his mother was concerned about prolonged steroid use and requested trying crisaborole ointment. After eight weeks of crisaborole ointment application, his skin condition had greatly improved (Figure 2A and 2B). Although at first, the ointment caused skin irritation, this was easily alleviated with the use of a moisturizer.

Learning point: Crisaborole seems to induce irritation, burning, and stinging more frequently in clinical practice than reported in clinical trials. The patient experienced irritation, burning, and stinging in the areas where crisaborole was used. Information and education on measures to prevent or to treat these side-effects were effective. The advice given included the use of a refrigerated moisturizer, frequently applied before and after application of the ointment to optimize crisaborole results and decrease irritation. The mother was encouraged to continue treatment after the physician discussed the expected outcomes of the therapy. The irritation was alleviated with the use of a moisturizer as instructed.

Figure 2A and 2B

Case 3: A 29-year-old neonatal intensive care unit (NICU) nurse developed hand dermatitis one year ago. During work, she frequently used a hand sanitizer causing pruritus and painful fissures. She had a negative history for AD, and other atopic disorders and Patch tests were negative. The eruptions cleared when she was on holiday. After consultation with the occupational health department for help and guidance, she received a special hand sanitizer. She refused TCS as she was concerned about developing skin thinning. Within eight weeks of starting crisaborole ointment, the condition had resolved. The ointment was well tolerated, and she resumed her work as a NICU nurse (Figure 3A and 3B).

Learning point: The patient with occupational irritant hand dermatitis did not want to use TCS. The alternative treatment with crisaborole ointment was successful for this patient. Use of crisaborole in the treatment of irritant contact hand dermatitis is off-label.

Figure 3A and 3B

Case 4: A 68-year-old woman with a history of rosacea also had recurrent facial eruptions. Patch testing was positive to Kathon CG, which was found in her laundry product which she had since avoided. Since TCS were unsuccessful, treatment with crisaborole ointment was started, used in combination with ceramides containing cream as needed. Her skin condition markedly improved within two weeks (Figure 4A – 4D).

Learning point: The ointment may be a useful alternative for TCS for facial areas in patients with concomitant facial inflammatory skin conditions. Although crisaborole may induce irritation, burning, and stinging, in this patient with underlying rosacea, the product was well tolerated. Topical steroids can induce a rosacealike eruption. Crisaborole did not aggravate this patient’s rosacea. Patch testing was useful in identifying the causative allergen. The use of crisaborole in allergic contact dermatitis is off-label.

Figure 4A and 4D

Case 5: An 11-month-old baby-boy had facial AD from the age of nine months. He had coincident acute myelogenous leukemia (AML) and was recovering from chemotherapy. His parents were concerned about TCS and TCI being immunosuppressive agents and due to his ongoing AML treatment refused them. Crisaborole ointment seemed a good alternative option. His skin condition improved within an eight week observation period, and no adverse events occurred (Figure 5A – 5D).

Learning point: In immunosuppressed or otherwise vulnerable patients, crisaborole ointment is an effective alternative to TCS to treat AD even on the face. Parental wishes to not use TCS or TCI were granted because crisaborole’s mechanism is not immunosuppressive. Although crisaborole is approved for use in individuals 2 years of age and older, it was safely and effectively used in this infant.

Figure 5A and 5D

Case 6: A 2-month-old baby boy presented with diffuse xerosis and AD present since three days of age. His condition impacted the entire family. His mother had applied Vaseline six times a day and TCS twice a day. He had not responded to treatment with several different types of TCS. The physician was concerned about absorption and possible adrenal axis suppression. After eight weeks of crisaborole ointment use, pruritus had subsided and both the baby and his family were able to sleep through the night (Figure 6A and 6B). Before starting treatment with crisaborole ointment, he had regularly had skin infections with MRSA, which did not reoccur since the start of the crisaborole ointment.

Learning point: Crisaborole proved to be a useful alternative for TCS where absorption and possible adrenal axis suppression were a major concern. Of interest is the resolved recurrent infection since the use of crisaborole, which may be attributed to the improved skin condition. Crisaborole is approved for use in individuals with AD two years of age and older.

Figure 6A and 6B

Case 7: A 15-year-old male had recurrent resistant atopic dermatitis and dyspigmentation from chronic TCS use. Treatment of the generalized flares and superinfection consisted of intravenous antibiotics and oral cyclosporine, to which he had a good initial response. To address his concern about TCS use and the desire for a simpler regimen, twice daily application with crisaborole ointment was started while continuing the cyclosporine. After eight weeks of use, he had an excellent response, with marked improvement in his quality of life. Whenever the patient stops topical crisaborole, some AD returns (Figure 7A and 7B).

Learning point: The use of crisaborole ointment in combination with systemic therapy was effective for this patient. The ointment is to be applied at the first sign of a flare before lesions develop and avoided the need to increase systemic therapy. As a result, he gained confidence in controlling his skin condition and improving his outlook on his situation.

Figure 7A and 7B

Case 8: A 5½-year-old boy had mild-to-moderate AD since the age of three and recently developed symptomatic hand and feet involvement. The rationale for crisaborole use on his hands and feet was the suboptimal response to previous TCS/TCI therapy. Concomitant use of TCS and TCI was continued together with crisaborole. His skin had almost cleared after eight weeks of crisaborole ointment use (Figure 8A – 8D).

Learning point: An incremental benefit of adding crisaborole as part of a combination regimen with TCS and TCI TCI introduces new possibilities for patients with AD on their hands and feet.

Figure 8A and 8D

Case 9: Since the first months of life, a 5-year-old male has had moderate-to-severe AD with symptomatic painful involvement of his hands, impacting daily activities. He had difficulty handling toys and interacting with other children and their parents. TCS and TCI treatments were not successful. With crisaborale, his hand palms and wrists’ involvement almost completely cleared. (Figure 9A – 9E).

Learning point: Effective penetration of crisaborole on thicker skin such as hand-palms and foot-soles may facilitate improvement in these special sites.

Figure 9A and 9B

Figure 9C and 9E

Case 10: A 4-year-old girl had AD. TCS therapy was started for her flaring disease. Her mother was concerned about vaccines and TCS use. Crisaborole ointment treatment was started to address the mother’s concerns. At eight weeks of ointment application, there was an 80% clinical improvement; however, some moderate AD persisted at some sites which required strong TCS.

Learning point: Although the crisaborole ointment did not completely resolve the disease, the mother preferred it to TCS for milder lesions and wished to reserve TCS for more resistant lesions.

Figure 10A and 10G

Case 11: A 12-year-old male with AD since infancy had involvement of the hands and limbs. His condition failed to show improvement from intermittent TCS. The rationale for starting crisaborole ointment was the family’s frustration with the lack of results and a possible penetration advantage of the ointment on the hands. A left/right assessment of clobetasol versus crisaborole ointment was conducted. His mothers’ perceptions were that his hands both improved, but the crisaborole ointment was more effective than clobetasol. On the arms and legs, both treatments were successful, but clobetasol outperformed crisaborole ointment. The therapy was continued after the eight weeks study period as the family was happy with the treatment response. No adverse events occurred. Subsequently, mom used crisaborole alone on his hands and had ongoing good maintenance and prevention of flares. (Figure 10A – 10G). Follow up results are shown in Figure 11A – 11E.

Learning point: The crisaborole ointment performed better on the hands than clobetasol, however when used on the arms and legs, the reverse was the case, indicating that the ointment may be particularly useful on thicker skin areas.

Figure 11A and 11E

Discussion

For each case, the age, skin type, underlying skin condition, rationale for using crisaborole, and in some cases, treatment duration were highlighted as well as its role as part of a maintenance/prevention and treatment regimen. The cases presented a spectrum of clinical responses to crisaborole, including instances of poor response, such as in case 10, where AD persisted, and TCS was further needed. The panel discussed challenges of recognizing and managing AD in darker skin which may be addressed using crisaborole ointment, although studies are needed to confirm possible benefits. Most of the cases were atopic dermatitis, the approved indication. Two other types of dermatitis (hand dermatitis, allergic contact dermatitis) were included although they have not approved indications since these conditions are often difficult to treat and do not always respond to topical steroids. In addition, on the face, topical steroids may be associated with a greater potential for adverse events.

Steroid Phobia

Steroid phobia refers to the negative feelings and beliefs related to TCSs experienced by patients and patients’ caregivers. The panel expressed concerns that this phenomenon may be a contributing factor in treatment failure in AD patients. A systematic review²² found that TCS phobia is present across all cultures and that adequate information for patients and parents is lacking. The authors of the systematic review propose that the sources from which patients are receiving information about TCS may be targetable for intervention to increase adherence to TCS treatment regimens.²²

Crisaborole can be an effective alternative for TCS and TCI, especially in patients with conditions requiring long-term TCS or TCI use.

In case of safety concerns (even when subjective) with TCS and TCI use in young patients or concerns about steroid absorption in all groups, patients can safely use crisaborole ointment. Moreover, preservatives in crisaborole pose no safety issues. The panel agreed that crisaborole ointment provides a good safe alternative to TCS and TCI in such cases, enhancing treatment adherence and thus outcomes.

Irritation, Burning and Stinging

Crisaborole seems to induce irritation, burning, and stinging more frequently in clinical practice than reported in clinical trials.^3,6,19 This side effect was also reported for two of the presented cases (case 2 and 4). The panel suggested that in their experience, irritation, burning, and stinging are more quickly resolved than in the case of TCI use, where similar side effects are also observed. If TCI related stinging occurs most clinicians will apply steroids temporarily and then subsequently TCIs are usually tolerated.

The panel recommended providing information on this issue and education on measures to prevent or to treat it before the start of the treatment with crisaborole. The panel recommended frequent use of a refrigerated moisturizer before and after application of the ointment, and the use of an anti-itch lotion as needed throughout the day. The panel further suggested that it may be helpful to have patients testing crisaborole on healthy skin. Modify or discontinue the treatment if the formulation triggers burning or stinging even on healthy skin with concomitant use of a refrigerated moisturizer. The panel discussed avoiding crisaborole ointment use on severely flaring skin and starting with TCS until the flare is controlled, followed by crisaborole ointment.

Antibiotic Resistance

Antibiotics are commonly used as part of the management of AD. However, only a minority of patients with AD have clinically significant S. aureus infection. Moreover, data is lacking for highly beneficial outcomes with exclusive use of antibiotics in the management of AD.²³ Case 6 shows an example of the possible use of crisaborole as a steroid-sparing and antibiotic-sparing agent. Because of antibiotic resistance, the use of the crisaborole ointment may be of interest and aligns with current emphasis on antibiotic stewardship in AD. Anti-inflammatory agents control eczema, which leads to less frequent infections and less antibiotic use.

Combination Treatment

Combining or alternating crisaborole with TCS or TCI may be successful for more severe disease. The ointment was safely used in time-intervals between the application of a moisturizer, TCS, or in combination with systemic therapy. Several cases showed a marked improvement in the skin condition of the treated patients and no adverse events.

Specific Body Locations

Case 4 shows an example of the safety and tolerability of crisaborole when used on specific sites (e.g., face and lips). An incremental benefit of crisaborole use as part of a combination regimen was shown in a patient (case 8) who recently had AD involvement of his feet, with hyperkeratosis and desquamation.

The rationale for crisaborole use, in this case, was good absorption of the ointment due to the relatively small size of the molecule allowing better penetration.

Case 11 showed beneficial crisaborole use on the hands, which did not improve with intermittent TCS application. This patient conducted a real-time comparative test using clobetasol on one side of the body and crisaborole on the other. Crisaborole worked better on the hands while clobetasol showed better results on his arms and legs.

The use of crisaborole for non-AD (case 3) was shown in a patient with occupational HD, which resulted in complete response. Advisors recommended further studies of crisaborole on the hands and feet (e.g., the study of occupational hand dermatitis and penetration study) to support the use of the ointment for these complex areas.

Table 1: Summary of the eleven cases studies
Case 1: TCS^a: Betametasone dipropionate 0.1% ointment, Mometasone ointment, TCI^b. Tacrolimus 0.1% ointment, Skincarec: Hydratation-Eucerin, Aquaphor, Aderma cleanser and hydrating agent.
Case 2: TCS^d: Desonide cream BID x 1 year, Hydrocortisone 17 valerate UNG BID x 1 year.
Case 3: TCS^e: Hydrocortisone cream
Case 4: TCS^f: 1% hydrocortisone cream
Case 6: TCS^g: Hydrocortisone 2.5%g then switched to desonide for body, Dermasmoothe FS for scalp and face. Then switched to hydroval 0.2% ointment to entire body.
Case 8: TCS^h: 0.1% betametasone valerate ointment (body), 0.1% protopic ointment (face).
Case 9: TCSⁱ and TCI: Betametasone dipropionate 0.1% ointment, Mometasone ointment, Tacrolimus 0.1% ointment.
Case 10: TCS^j: Begin with strong corticosteroids, Desonide ointment for the face, Betamethasone valerate 0,1% ointment for the hands and feet.
Case 11 : TCS^k : Clobetasol.

Atopic dermatitis (AD), Twice daily (BID), Crisaborole ointment (CO), Adverse events (AEs), Neonatal intensive care unit (NICU), Hand Dermatitis (HD), Medical history (Hx), Acute Myelogenous Leukemia (AML), Intravenous (IV) Oral (PO).

Maintenance Therapy

The panel discussed the spectrum of clinical response of crisaborole used in adjunction to a moisturizer as maintenance therapy and suggested that crisaborole ointment should start at the first sign of a new flare before the development of lesions. TCS should be added if it is not successful. Currently, data on the use of crisaborole ointment for long term maintenance therapy is lacking; however, the panel suggested further studies of crisaborole as maintenance therapy.

Conclusion

The discussed cases reflect the panels’ real-world clinical experience with crisaborole for the treatment of patients with AD and the off-label treatment of irritant dermatitis. The panel suggested that crisaborole ointment provides a good safe alternative to TCS and TCI. Use of crisaborole should be avoided on severely flaring skin and for those that experience irritation while testing it on unaffected skin areas.

Acknowledgement

The authors acknowledge and thank Anneke Andriessen, PhD, for her invaluable assistance with preparing this manuscript.

Limitations

The cases are intended to illustrate the real-world experience rather than reflect a controlled clinical trial data environment, nor do they presented cases mirror statistical outcomes. Use crisaborole ointment in off-label settings is left up to the discretion of the treating health care professional after careful clinical evaluation.

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