Phase 3 Study of Weekly Subcutaneous Anifrolumab Added to Standard Care for Adults with Moderate to Severe Polymyositis or Dermatomyositis

What this Trial Is About

Researchers are evaluating the effectiveness and safety of subcutaneous anifrolumab compared with a placebo in adults with moderate to severe Idiopathic Inflammatory Myopathies IIM, including polymyositis PM and dermatomyositis DM. This phase III, multicenter, randomized, placebo-controlled, and double-blind study aims to assess how adding anifrolumab to standard care affects overall disease activity in these patients. Participants will receive either anifrolumab or a matching placebo as a subcutaneous injection once a week for 52 weeks, alongside their standard of care treatments. After this initial period, all participants will be offered open-label anifrolumab once weekly for an additional 52 weeks, allowing further evaluation of long-term treatment effects. During the study, participants will be monitored through various assessments including muscle strength tests, disease activity scores, corticosteroid usage, and skin severity indexes over 52 weeks. The main outcome measure is the Total Improvement Score response at 52 weeks. Safety and disease activity will be carefully tracked throughout the treatment and follow-up periods, with study participation potentially lasting up to two years.

A Study to Investigate the Efficacy and Safety of Anifrolumab Administered as Subcutaneous Injection and Added to Standard of Care Compared With Placebo Added to Standard of Care in Adult Participants With Idiopathic Inflammatory Myopathies (Polymyositis and Dermatomyositis)