Telitacicept add-on therapy in refractory idiopathic inflammatory myopathy: insights from a pilot study

Abstract Objectives This study aimed to evaluate the therapeutic efficacy of telitacicept based on the conventional treatment in adults with idiopathic inflammatory myopathy (IIM), focusing on its impact on clinical manifestations. Methods IIM patients who had been treated with telitacicept for at least 3 months based on the conventional treatment from January 2023 to January 2024 were included in this study. The clinical response to telitacicept was determined based on the ACR/EULAR criteria for minimal, moderate, and major improvement in the total improvement score (TIS). Disease activity was monitored using Core Set Measures (CSMs), while myositis damage was assessed with established assessment tools. The Manual Muscle Test assessed the muscle performance for 8 muscle groups (MMT-8). Results A total of 11 patients administered with telitacicept (160 mg per week) were included in this study. Post-treatment assessments revealed improvements in all patients according to ACR/EULAR criteria. Notably, there was a significant reduction in the prednisone dosage from baseline to last visit (27.05 ± 12.47 mg to 12.05 ± 7.32 mg; p< 0.005). Enhancements were observed in MMT-8 scores improved (from 109.18 ± 14.18–137.64 ± 15.28; p< 0.005) and in the reduction of creatine kinase (CK) levels (from 2670.27 ± 2675.00 U/l to 561.09 ± 754.09; p< 0.05). Conclusion Telitacicept demonstrated effectiveness in treating refractory inflammatory myopathy, contributing to a significant reduction in steroid dosage among the patients. These findings highlight the potential of telitacicept as a valuable therapeutic option in the management of IIM.