Real-world experience of anifrolumab in 30 patients with refractory DM: a multicentre–multidisciplinary retrospective study

OBJECTIVE: To assess real-world outcomes of anifrolumab (ANI) in refractory systemic DM. METHODS: This multicentre and multidisciplinary, retrospective study evaluated 30 DM patients receiving ANI through compassionate use. Disease activity was assessed at baseline and months 1, 3, 6 and 12 using Cutaneous Dermatomyositis Disease Area and Severity Index Activity Score (CDASI-A), Manual Muscle Testing-8 (MMT-8), joint and pulmonary evaluation and glucocorticoid tapering. Safety included adverse event documentation and treatment discontinuation rates. RESULTS: Treatment indications included refractory cutaneous (73.3%), cutaneous-muscular (13.4%, including one pulmonary progression case) and other manifestations (13.3%). ANI was initiated without concomitant immunosuppressive therapy in 50% of patients. Cutaneous improvement was observed from month 1 (CDASI-A: 23 [IQR 10.8-30.5] to 6 [IQR 3-10]; P < 0.001), with heliotrope rash and Gottron's papules responding faster than alopecia. Muscular function improved (MMT-8: 142.5 [IQR 127-148] to 146.5 [IQR 139-150]; P < 0.05) with creatine kinase (CK) normalization (332 IU/l [IQR 211.5-893.5] to 146 IU/l [IQR 106.5-481.8]) at month 1. All active arthritis patients (n = 3) achieved remission, with no articular flares observed among patients with historical joint involvement. Interstitial lung disease cases (n = 6) demonstrated stabilization or improvement as assessed by pulmonary function tests and/or computed tomography. Glucocorticoid dose significantly reduced (P < 0.001), discontinued in 50%. Adverse events were mild (16.7% patients); one 89-year-old patient died from pneumonia. One patient required upadacitinib for refractory pruritus; one discontinued ANI for efficacy loss. CONCLUSION: ANI showed rapid, multisystem efficacy in refractory DM with significant steroid-sparing effects and a favourable safety profile.