• Dermatomyositis
• Polymyositis
• Outcome Assessment, Health Care

We thank Azevedo et al 1 for their correspondence in response to the publication of our viewpoint entitled ‘Myositis Clinical Trials and Tribulations’.2 The authors eloquently discuss additional clinical trial designs and analytical approaches that can increase the likelihood of participants being assigned to the treatment arm and facilitate drug approval in idiopathic inflammatory myopathies (IIM). At this juncture, we would like to take the opportunity to discuss an additional point. While clinical trials offer the highest-quality evidence for treatment effectiveness, they are expensive, time-consuming and may not always be feasible. Observational comparative effectiveness studies such as target trial emulation can also provide valuable information on quantifying the effect of a treatment.3 However, this approach requires large prospective observational databases with robust follow-up information. In a rare disease such as myositis, this can be accomplished by establishing a global myositis registry leveraging common data elements and common data models in an effort to harmonise existing databases. We also agree with the authors that the scarcity of IIM clinical trials that enroll children with juvenile myositis is concerning. Close collaboration between paediatric and adult providers is key to conduct ‘age-inclusive’ trials in IIM. As stated by the authors, theMyositis International Health and Research Collaborative Alliance (MIHRA) will be instrumental in overcoming these challenges by (1) establishing a clinical trial network, (2) developing a global myositis database and (3) bringing together all the relevant stakeholders including patients, paediatric and adult clinicians, researchers and industry partners from around the world. This will increase efficiency, reduce redundancy and maximise benefit for patients with IIM.