Efficacy of Janus kinase inhibitors in rheumatoid arthritis.

Background: Janus kinase inhibitors (JAKis) is a new therapeutic class in autoimmune and inflammatory diseases. Four molecules are approved in rheumatoid arthritis (RA) in Europe. Recently, questions have raised about adverse events. In this context, a synthesis of the efficacy data of JAKis in RA is of use.

Method: We performed a literature review based on published articles about efficacy of JAKis in RA, including clinical trials, registries, retrospective and prospective cohorts as well as database analysis.

Results: Based on the phase III clinical trials, JAKis are effective in comparison to placebo, methotrexate and tumour necrosis factor inhibitors. Based on registries, cohorts and post hoc analysis of phase III clinical trials, several parameters might modulate the efficacy of JAKis: the serological status, a short duration of the disease or the presence of poor prognostic factors. Preliminary data suggest that early ultrasonographic evaluation might help to predict the medium-term progression.

Conclusion: Some clinical, biological and imaging parameters seem to influence the response to JAKis and should be evaluated in larger studies. In addition to factors that might influence the efficacy of JAKis, the safety profile and risk factors should be considered before initiating JAKis in a patient.