Clinical features, treatment, and outcomes of anti-PD-1/PD-L1 immune checkpoint inhibitors induced dermatomyositis

BACKGROUND: This study aims to clarify clinical manifestations, diagnostic methods, treatment approaches, and prognostic outcomes of anti-programmed death (PD-1)/programmed death- ligand 1(PD-L1) drugs-induced dermatomyositis (DM). METHODS: This study conducted a retrospective analysis of DM cases induced by anti-PD-1/PD-L1 agents. Through systematic retrieval of relevant databases up to May 7, 2025, case reports were comprehensively collected and comprehensively evaluated. RESULTS: A total of 49 patients were enrolled, with males accounting for 75.5%. The median age was 66 years (15-85 years). After receiving anti-PD-1/PD-L1 drugs for various tumors, especially lung cancer and melanoma, 35 patients (71.4%) developed de novo dermatomyositis. Notably, compared with patients with a history of dermatomyositis, those with de novo dermatomyositis experienced symptom onset after a longer duration and more treatment cycles of anti-PD-1/PD-L1 drugs. For intervention and treatment strategies, 39 patients (79.6%) discontinued anti-PD-1/PD-L1 drugs, while only 2 patients (4.1%) continued treatment. Following clinical interventions including systemic steroid therapy, immunoglobulin administration, and other immunosuppressive agents, the skin- and muscle-related symptoms of the vast majority of patients improved or completely resolved. CONCLUSION: During anti-PD-1/PD-L1 therapy, closely monitor patients' cutaneous and muscular symptoms to detect DM early. For diagnosed DM patients, implement timely interventions according to symptom severity.