Efficacy and Safety of Etanercept in Japanese Patients With Stevens–Johnson Syndrome and Toxic Epidermal Necrolysis Unresponsive to Systemic Steroid Therapy: A Multicenter, Open‐Label, Single‐Arm Study

Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are severe, life-threatening cutaneous adverse reactions that have limited treatment options when systemic corticosteroids prove ineffective. To assess the efficacy and safety of etanercept in patients with SJS/TEN who failed to respond adequately to systemic corticosteroid therapy. In this multicenter, open-label, single-arm study conducted in Japan, patients with SJS or TEN unresponsive to ≥ 2 days of systemic corticosteroids (prednisolone-equivalent ≥ 20 mg/day) were enrolled. Etanercept 50 mg was administered subcutaneously on Day 1, with additional doses on Days 8 and 15 if re-epithelialization remained incomplete. The primary outcome was time to complete re-epithelialization. Secondary endpoints included time to cessation of skin progression, hospitalization duration, disease severity scores, ocular complications, and safety outcomes. Eight Japanese patients (mean age: 63.4 years; SJS: 5, TEN: 3) were treated. The median time to complete re-epithelialization was 10 days (95% Confidence interval: 6.0-20.0). All patients achieved re-epithelialization within 29 days. The mean time to cessation of skin progression was 4.0 days, and the mean hospitalization duration was 19.3 days. No deaths occurred. Adverse events were reported in six patients (75%), including two serious infections (cytomegalovirus and cryptococcosis). However, none were judged related to etanercept. No treatment discontinuations occurred. Etanercept could be an effective and safe treatment option for patients with SJS/TEN unresponsive to systemic corticosteroids. These findings warrant validation in larger, controlled studies.