Tofacitinib therapy in refractory inflammatory myositis: a retrospective cohort study of 41 patients

To evaluate the efficacy and safety of tofacitinib in treatment-refractory inflammatory myositis in a real-world clinical setting.

All patients with refractory inflammatory myositis treated with tofacitinib from a single urban centre in Vancouver, British Columbia, Canada, were included from June 2016 to December 2022. The medical records of these patients were retrospectively reviewed.

A total of 41 patients were included, 23 with classic DM, 12 with amyopathic DM (ADM) and six with PM phenotype. The patients failed an average of four to five non-steroidal immunosuppressants before initiation of tofacitinib. In the classic DM and ADM group, tofacitinib offered clinically and statistically significant cutaneous improvement. In all myositis patients including the PM phenotype, no meaningful muscle strength response to tofacitinib was observed. 53.7% of the patients discontinued tofacitinib due to lack of benefit or death. Of the 19 patients who remained on tofacitinib at the conclusion of this study, tofacitinib demonstrated clinically and statistically significant improvement in cutaneous disease activity.

Tofacitinib appears to be highly effective in targeting cutaneous manifestations in classic DM and ADM; however, minimal benefit in muscle strength in the DM or PM phenotype were observed.