Abstract
<jats:title>Abstract</jats:title> <jats:sec> <jats:title>Objectives</jats:title> <jats:p>To assess the effects of 24 weeks active treatment with baricitinib, a JAK1/2 inhibitor, in adult idiopathic inflammatory myopathy (IIM).</jats:p> </jats:sec> <jats:sec> <jats:title>Methods</jats:title> <jats:p> Patients with active dermatomyositis (DM) or polymyositis (PM) were enrolled into a 1:1 randomized treatment delayed-start design clinical trial ( <jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="clintrialgov" xlink:href="NCT04208464">NCT04208464</jats:ext-link> ). Participants received 24 weeks baricitinib plus 12 weeks follow-up (Immediate-start), or 12 weeks standard of care plus 24 weeks baricitinib (Delayed-start). The primary outcome was clinical response after 24 weeks active treatment, defined as minimal improvement (Total Improvement Score >20 [TIS20]). Secondary outcomes included: TIS40 (moderate), TIS60 (major) response, between-arm comparison, time to achieve response, change in clinical outcome measures. steroid-sparing and cumulative adverse events. </jats:p> </jats:sec> <jats:sec> <jats:title>Results</jats:title> <jats:p>14/15 (93%) randomized participants (mean age 43.2 years [11.6 SD]; 13 DM, 2 PM; 11 female) completed the study (baseline to 36 weeks) and all achieved TIS20 at 24 weeks post-active treatment (95% exact CI 0.68-1.00). 9/15 (60%) achieved TIS40 response and 2/15 (13%) TIS60 response. At 12 weeks post-randomization, 11/15 (73%) patients achieved at least TIS20 (95%CI 0.45-0.92), including all Immediate-start arm patients and four Delayed-start arm patients. At the same time point, evidence of a difference was noted for patient global, extramuscular, CDASI skin activity, pain, fatigue and SF-36 mental/physical health scores. Two hospitalisation serious adverse events were documented, neither related to study drug.</jats:p> </jats:sec> <jats:sec> <jats:title>Conclusions</jats:title> <jats:p>Treatment of IIM with baricitinib resulted in improved clinical outcome after 24 weeks. Significant improvement after 12 weeks treatment was also evident. No significant safety concerns were raised. A randomized placebo-controlled trial is needed to confirm the efficacy in patients with IIM.</jats:p> </jats:sec> <jats:sec> <jats:title>Clinical trial registration</jats:title> <jats:p>EudraCT Number: 2019-003868-42</jats:p> <jats:p> ISRCTN Number /Clinical trials.gov Number: <jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="clintrialgov" xlink:href="NCT04208464">NCT04208464</jats:ext-link> </jats:p> <jats:p> <jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="uri" xlink:href="https://clinicaltrials.gov/study/NCT04208464">https://clinicaltrials.gov/study/NCT04208464</jats:ext-link> </jats:p> </jats:sec>