Sustained long-term efficacy and safety of adalimumab in paediatric patients with severe chronic plaque psoriasis from a randomized, double-blind, phase III study

Background: Adalimumab (ADA) (Humira^®, AbbVie Inc., U.S.A.) is approved by the European Medicines Agency for children aged ≥ 4 years with severe plaque psoriasis. Objectives: To evaluate the long-term efficacy and safety of ADA in children with severe plaque psoriasis. Methods: Results are presented from the 52-week long-term extension (LTE) of the randomized, double-blind, double-dummy, phase III trial, in children with severe plaque psoriasis (results from prior periods have been published). Patients aged ≥ 4 and < 18 years were randomized 1 : 1 : 1 to ADA 0·8 mg kg⁻¹ (40 mg maximum) or 0·4 mg kg⁻¹ (20 mg maximum) every other week or to methotrexate (MTX) 0·1–0·4 mg kg⁻¹ (25 mg maximum) weekly. The 16-week initial treatment (IT) period was followed by a 36-week withdrawal period and a 16-week retreatment period. Patients could enter the LTE at prespecified time points to receive ADA 0·8 mg kg⁻¹ (blinded or open label) or ADA 0·4 mg kg⁻¹ (blinded), or to remain off treatment. Efficacy is reported for patient groups according to doses received in the IT and LTE periods. Results: Of the 114 patients randomized in the IT period, 108 entered the LTE (n = 36 in each group); 93 received ADA 0·8 mg kg⁻¹. Efficacy (≥ 75% improvement from baseline in Psoriasis Area and Severity Index) was maintained or improved from entry to the end of the LTE: MTX(IT)/ADA 0·8(LTE) 31–86% of patients; ADA 0·4(IT)/0·4 or 0·8(LTE) 28–47%; ADA 0·8(IT)/0·8(LTE) 50–72%. No serious infections occurred in the LTE. Conclusions: After 52 weeks of long-term ADA treatment in children aged 4–18 years with severe plaque psoriasis, disease severity was reduced and maintained or further improved, as demonstrated by efficacy outcomes. No new safety risks were identified. What's already known about this topic?. The results from the first three periods of this phase III trial in children aged 4–18 years with severe plaque psoriasis suggest that adalimumab is a safe and efficacious treatment option in this population. What does this study add?. This is the first study to evaluate long-term treatment of adalimumab in children with severe psoriasis, and the first to evaluate switching from methotrexate to adalimumab in this population.