Topical calcineurin inhibitors in pediatric atopic dermatitis: a critical analysis of current issues

Systematic review of published trials: long-term safety of topical corticosteroids and topical calcineurin inhibitors in pediatric patients with atopic dermatitis

BACKGROUND

Many clinicians have concerns about the safety of atopic dermatitis (AD) treatments, particularly in children requiring long-term daily maintenance therapy. Topical corticosteroids (TCS) have been widely used for >5 decades. Long-term TCS monotherapy has been associated with adverse cutaneous effects including atrophy, rebound flares, and increased percutaneous absorption with potential for adverse systemic effects. Topical calcineurin inhibitors (TCIs), tacrolimus and pimecrolimus, available for 1-2 decades, are not associated with atrophy or increased percutaneous absorption after prolonged use and have much lower potential for systemic effects. However, since 2006 TCIs have carried a controversial Boxed Warning based on a theoretical risk of malignancy (eg, skin and lymphoma) that has limited TCI use for standard-of-care maintenance therapy.

METHODS

A comparative systematic search of PubMed was done for long-term (≥12 week) clinical trials of TCS or TCI treatment in patients <12 years with AD. Citations were reviewed for inclusion based on MeSH terms, abstracts, and relevant article text. Studies were excluded if they did not encompass subjects <12 years, or were <12 weeks' duration, retrospective, meta-analyses, or limited to anecdotal case reports.

RESULTS

Of 27 trials meeting criteria, 21 included 5825 pediatric patients treated with TCIs, and 6 included 1999 patients treated with TCS. TCS studies were limited to low- to mid-potency products, and all but one study lacked a vehicle control. Eight TCI studies were vehicle-controlled, and safety data were well reported, with ≤5 % of patients reporting discontinuation due to adverse effects (DAEs). Cutaneous and systemic adverse events (AEs) were similar in TCI and vehicle groups, with no reports of lymphoma. Safety data in TCS trials were less well reported. DAE incidence was addressed in just 2 trials, and systemic and cutaneous AEs were mostly unreported.

CONCLUSIONS

Data supporting long-term use of TCIs are robust, documenting safety and efficacy, while data supporting long-term TCS use are limited to low- to mid-potency products. Our review identifies a lack of information on the safety of commonly prescribed, long-term monotherapy with mid- to high-potency TCS in pediatric AD, and supports standard-of-care maintenance therapy with TCIs and intermittent use of low- to mid-potency TCS for flares.

Spotlight on topical pimecrolimus in pediatric atopic dermatitis

Topical pimecrolimus 1% cream (Elidel) [hereafter referred to as topical pimecrolimus] is a nonsteroidal alternative in the treatment of pediatric atopic dermatitis. In vehicle-controlled, short-term, continuous-use trials in pediatric patients with mild to moderate atopic dermatitis, topical pimecrolimus was effective in treating disease symptoms. Topical pimecrolimus was effective in preventing disease flares and reducing the need for topical corticosteroids in longer term, intermittent-use trials. In addition, topical pimecrolimus was associated with improvements in the health-related quality of life of pediatric patients with atopic dermatitis and their parents. In vehicle-controlled trials, topical pimecrolimus was generally as well tolerated as vehicle. Topical pimecrolimus showed similar efficacy to topical tacrolimus 0.03% ointment in a short-term, continuous-use trial and the two agents had a generally similar tolerability profile. Although comparative data between topical pimecrolimus and topical corticosteroids are lacking in pediatric patients, and the long-term tolerability (beyond 1-2 years) of topical pimecrolimus is yet to be established, topical pimecrolimus is a useful agent in the management of pediatric patients with mild to moderate atopic dermatitis who do not achieve satisfactory treatment with other topical pharmacologic treatments, including topical corticosteroids.

Topical pimecrolimus: a review of its use in the management of pediatric atopic dermatitis

Topical pimecrolimus 1% cream (Elidel) [hereafter referred to as topical pimecrolimus] is a nonsteroidal alternative in the treatment of pediatric atopic dermatitis. In vehicle-controlled, short-term, continuous-use trials in pediatric patients with mild to moderate atopic dermatitis, topical pimecrolimus was effective in treating disease symptoms. Topical pimecrolimus was effective in preventing disease flares and reducing the need for topical corticosteroids in longer term, intermittent-use trials. In addition, topical pimecrolimus was associated with improvements in the health-related quality of life (HR-QOL) of pediatric patients with atopic dermatitis and their parents. In vehicle-controlled trials, topical pimecrolimus was generally as well tolerated as vehicle. Topical pimecrolimus showed similar efficacy to topical tacrolimus 0.03% ointment (hereafter topical tacrolimus) in a short-term, continuous-use trial and the two agents had a generally similar tolerability profile. Although comparative data between topical pimecrolimus and topical corticosteroids are lacking in pediatric patients, and the long-term tolerability (beyond 1-2 years) of topical pimecrolimus is yet to be established, topical pimecrolimus is a useful agent in the management of pediatric patients with mild to moderate atopic dermatitis who do not achieve satisfactory treatment with other topical pharmacologic treatments, including topical corticosteroids.

Topical use of pimecrolimus in atopic dermatitis: update on the safety and efficacy

Pimecrolimus has been approved for more than five years for the treatment of atopic dermatitis in Germany. An important difference in the safety profile of this drug compared with topical corticosteroids is the lack of potential side effects which are often observed upon prolonged use of topical corticosteroids (skin atrophy, steroid-induced rosacea or perioral dermatitis). Even after prolonged use in sensitive skin areas, no tolerance to this drug is induced, in contrast to that seen with topical corticosteroids. The most common side effect of pimecrolimus is burning. Placebo-controlled studies suggest that pimecrolimus is associated with a slightly increased incidence of herpes simplex infections. Compared with topical corticosteroids, pimecrolimus does not increase the overall incidence of skin infections (including recurrent herpes simplex infections). So far, clinical studies with pimecrolimus have not shown any evidence of an increased risk of malignancy. The analysis of spontaneously reported adverse events has also not shown any evidence of malignancy caused by pimecrolimus. This corresponds with the results of a case-control study from a large U.S. database. According to the German guidelines on atopic dermatitis, topical calcineurin inhibitors are indicated when topical corticosteroids are not indicated or when an anticipated lengthy treatment course would lead to inevitable side effects. On sensitive areas such as face, intertriginous regions and scalp, they are preferred as first-line choice over topical corticosteroids

Topical corticosteroids and topical calcineurin inhibitors in the treatment of atopic dermatitis: focus on percutaneous absorption

The 2 primary classes of drugs used to treat atopic dermatitis (AD) are topical corticosteroids (TCSs) and topical calcineurin inhibitors (TCIs). For maximum efficacy, topical agents must efficiently penetrate the skin but, for optimal safety, should not be absorbed into the bloodstream. TCSs, a mainstay in AD treatment for more than 50 years, can potentially be absorbed into the systemic circulation, particularly when used on young children, for prolonged periods, or on areas of thin and sensitive skin, such as the eyelids, face, and flexures. There is a risk of cutaneous and systemic adverse events, including suppression of the hypothalamic-pituitary-adrenal axis and related sequelae, especially when potent or superpotent TCSs are used for extended periods. Ideally, TCSs should be used for short periods (2-4 weeks), but clinical reality often necessitates longer use. TCIs also effectively and safely treat AD, with the most commonly observed local adverse events being skin irritation and burning. These agents have demonstrated good penetration of the skin with minimal systemic absorption, as evidenced by low blood concentrations, and can be used safely on thin and sensitive skin. The use of mid-potency TCSs to treat acute flares involving skin of normal thickness, followed by the introduction of TCIs for maintenance therapy, constitutes an appropriate application of both drug classes. Pharmacists with a clear understanding of how both types of agents affect the systemic circulation have the opportunity to inform patients and caregivers about benefits and limitations of different therapeutic agents, address patient concerns about adverse events, and help patients understand how to use medical therapies appropriately.

Systemic therapy of atopic dermatitis in children

Atopic dermatitis (AD) is a common disease in childhood that is a serious burden on patients and their families. Most AD is mild and can be managed with the use of emollients and standard therapy consisting of topical corticosteroids or topical calcineurin inhibitors. However, in a subgroup of patients with moderate to severe AD, the disease is recalcitrant to topical therapy and systemic treatments become necessary. Short courses of systemic corticosteroids are often used in clinical practice, but their use is controversial. International guidelines suggest that in the case of acute flare-ups, patients might benefit from a short course of systemic corticosteroids, but long-term use and use in children should be avoided. Ciclosporin is an immunosuppressant agent that acts directly on cells of the immune system, with an inhibitory effect on T cells. When AD cannot be controlled by standard topical therapies, ciclosporin significantly decreases symptom scores, disease extent, pruritus and sleep deprivation, and improves quality of life. The most frequent adverse effects associated with the use of ciclosporin are hypertension and renal dysfunction, but they are usually reversible after drug discontinuation. Ciclosporin has been found to be safely used, effective and well tolerated in children with severe AD. However, studies to assess the long-term effectiveness and safety of ciclosporin in AD are lacking. In patients for whom ciclosporin is not suitable, or when there is a lack of response, alternative drugs should be considered, such as azathioprine or interferon-gamma. Intravenous immunoglobulins and the monoclonal antibody infliximab only have a place in the systemic therapy of AD when other drugs have failed. Mycophenolate mofetil has recently been introduced in the treatment of recalcitrant AD. Efalizumab and omalizumab are monoclonal antibodies with a possible future role in the treatment of AD, but further studies are needed.

A multidisciplinary approach to evaluation and treatment of atopic dermatitis

Atopic dermatitis is a common, complex disease that frequently follows a chronic, relapsing course. The disease can impact the quality of life (QOL) of patients and families to a significant degree. Patients and caregivers may focus on unproven triggers at the expense of proper skin care. A multidisciplinary approach is needed to comprehensively evaluate triggers and response to treatment, address confounding factors including sleep disruption, and educate patients and caregivers.

Atopic dermatitis: a review of recent advances in the field

Atopic dermatitis is increasing in prevalence and currently affects 15–30% of children in urban areas. Immune dysregulation and an impaired epidermal barrier are important factors in the pathogenesis of this disease. Pruritus and a chronic relapsing remitting course are hallmarks of the disorder, and sleep disturbance can occur in both the patient and family. Preventive interventions include exclusive breastfeeding in the first 4 months of life and withholding solid foods for 6 months. The avoidance of irritants and the use of emollients decrease flares. Topical corticosteroids remain the mainstay of therapy, and should be judiciously utilized. Excessive and inappropriate use must be avoided, as well as ‘steroid phobia’. The topical calcineurin inhibitors can be useful adjuncts. Systemic therapies are available for severe disease, but carry risks of adverse effects.