Clinical endpoints in myositis: challenges and ways forward

Purpose of review This review addresses the challenges and advances in clinical endpoints for myositis, with a particular focus on ensuring comprehensive assessment of both muscle and skin disease activity. The relevance of this review stems from recent developments in outcome measures and their implications for clinical trial design and patient inclusivity. While quality of life (QoL) and lung involvement are also important aspects of myositis, they are beyond the scope of this review and need to be addressed in future studies. Recent findings Traditional outcome measures like the Total Improvement Score (TIS) have limitations, especially for patients with skin-predominant dermatomyositis (DM). Recent studies highlight the importance of incorporating skin-specific measures such as the Cutaneous Disease Area and Severity Index (CDASI) and the novel composite measure, Dermatomyositis Outcomes for Muscle and Skin (DMOMS). These measures provide a more balanced assessment of disease activity. Clinical trial data analyzed using these measures have demonstrated significant benefits for patients with both classic and amyopathic DM, emphasizing the need for their broader adoption. Summary Advancements in outcome measures are crucial for inclusive and effective myositis clinical trials. Incorporating comprehensive tools like the DMOMS can enhance the assessment of both muscle and skin disease activities, potentially leading to better therapeutic strategies and improved patient outcomes. This shift is essential for addressing the needs of all Idiopathic inflammatory myopathy patients, including those with skin-predominant DM.