Psoriasis and atopic dermatitis (AD) can impact quality of life (QOL) in pediatric patients, warranting early recognition and treatment.1 Topical agents often are inadequate to treat moderate to severe disease, but the potential toxicity of systemic agents, which largely include immunosuppressives, limit their use in this population despite their effectiveness. Our expanding knowledge of the pathogenesis of psoriasis (tumor necrosis factor [TNF] α and IL-23/TH17 pathways) and AD has led to targeted interventions, particularly monoclonal antibody biologics, which have revolutionized treatment for affected adults and more recently children. Several agents are approved by the US Food and Drug Administration (FDA) for pediatric psoriasis, and dupilumab is approved for pediatric AD. Herein, we discuss the latest developments in the treatment landscape for pediatric psoriasis and AD.
Pediatric Psoriasis
Methotrexate (MTX) and cyclosporine have been FDA approved for psoriasis in adults since 1972 and 1997, respectively.2 Before biologics, MTX was the primary systemic agent used to treat pediatric psoriasis, given its lower toxicity vs cyclosporine. The TNF-α inhibitor etanercept became the first FDA-approved biologic for pediatric psoriasis in 2016. Adalimumab has been available in Europe for children since 2015 but is not FDA approved. Certolizumab, a pegylated TNF-α inhibitor that distinctly fails to cross the placental barrier currently is in clinical trials (ClinicalTrials.gov identifier NCT04123795). Tumor necrosis factor α inhibitors have shown more rapid onset and greater efficacy during the first 16 weeks of use than MTX, including a head-to-head trial comparing MTX to adalimumab.3 A recent real-world study showed that pediatric patients receiving biologics, primarily TNF-α inhibitors, were more likely to achieve psoriasis area and severity index (PASI) 75 or clear/almost clear status (similar to PASI 90) than MTX and had higher drug survival rates.4
Ustekinumab targets both IL-12 and IL-23, which share the IL-23 receptor p40 subunit. It was the first biologic to target IL-23, which promotes the proliferation and survival of helper T cells (TH17). Ustekinumab has led to greater reductions in PASI scores than TNF-α inhibitors.5,6 Pediatric trials of guselkumab, risankizumab, and tildrakizumab, all targeting the IL-23 receptor–specific p19 subunit, are completed or currently recruiting (NCT03451851, NCT03997786, NCT04435600). Ixekizumab is the first IL-17A–targeting biologic approved for children.7 Secukinumab and the IL-17 receptor inhibitor brodalumab are in pediatric trials (NCT03668613, NCT04305327, NCT03240809). One potential issue with TH17 pathway inhibitors is their association with inflammatory bowel disease, a contraindication when considering if a patient is a potential candidate for treatment.
Skin disease can profoundly affect QOL during childhood and adolescence, a critical time for psychosocial development. In psoriasis, improvement in QOL is proportional to clearance and is greater when PASI 90 is achieved vs PASI 75.8 The high efficacy of IL-23 and IL-17A pathway inhibitors now makes achieving at least PASI 90 the new standard, which can be reached in most patients.
Pediatric AD
For AD in the pediatric population, systemic treatments primarily include corticosteroids, mycophenolate mofetil, azathioprine, cyclosporine, and MTX. Although cyclosporine was the favored systemic agent among pediatric dermatologists in one study,9 claims data analyses show that systemic corticosteroids are used much more often overall, prescribed in 24.4% (116,635 total cases) of children with AD vs nonsteroidal immunosuppressants in less than 0.5%.10 Systemic steroids are impractical given their side effects and risk for disease rebound; however, no immunosuppressants are safe for long-term use, and all require frequent laboratory monitoring. The development of biologics for AD largely involves targeting TH2-driven inflammation.11 Dupilumab is the only FDA-approved biologic for moderate to severe pediatric AD, including in patients as young as 6 years of age. Dupilumab inhibits activation of the IL-4Rα subunit, thereby blocking responses to its ligands, IL-4 and IL-13. Phase 3 trials are now underway in children aged 6 months to 5 years (NCT02612454, NCT03346434). The concomitant ameliorative effects of dupilumab on asthma and other allergic disorders, occurring in approximately 90% of children with moderate to severe AD, is an added benefit.12 Although dupilumab does not appear to modify the disease course in children with AD, the possibility that early introduction could reduce the risk for later developing allergic disease is intriguing.