THU0067 JAK SELECTIVITY AND THE IMPACT ON CYTOKINE SIGNALING INHIBITION AT CLINICAL RHEUMATOID ARTHRITIS DOSES

Real-world comparative effectiveness and safety of tofacitinib and baricitinib in patients with rheumatoid arthritis

OBJECTIVE

To compare the efficacy and safety of tofacitinib and baricitinib in patients with RA in a real-world setting.

METHODS

A total of 242 patients with RA who were treated with tofacitinib (n = 161) or baricitinib (n = 81) were enrolled. We evaluated efficacy and safety between tofacitinib and baricitinib using multivariable analyses to avoid confounding. Their clinical disease activity and AEs were evaluated for 24 weeks.

RESULTS

The mean (SD) DAS28-ESR change from baseline to 24 weeks was 1.57 (1.55) (tofacitinib) and 1.46 (1.36) (baricitinib). There was no significant difference in the clinical response between the two groups (adjusted mean difference, 0.04; 95% CI, -0.35 to 0.28). The efficacy was not significantly changed in the patients without concomitant MTX use in both groups, but the concomitant MTX use showed better clinical efficacy in the cases of baricitinib treatment. In both groups, the most common AE was herpes zoster infection, and the AE rates were similar between the two groups. However, the predictive factors contributing to clinical response as revealed by a multivariable logistic analysis differed. The concomitant oral steroid use was independently associated with the achievement of DAS-low disease activity in the tofacitinib group, whereas in the baricitinib group, the number of biological and/or targeted synthetic DMARDs previously used was associated.

CONCLUSIONS

Our findings indicate that tofacitinib and baricitinib had comparable continuing efficacies and safety profiles. However, there is a possibility that the influence of clinical characteristics on the treatment response differs. The comparison provides useful information to the optimal use of JAK inhibitors in real-world settings.

Impact of Janus Kinase Inhibition on the Treatment of Axial Spondyloarthropathies

Many immune cells and effector molecules (e.g. cytokines, Interferons, growth factors) utilize different combinations of Janus kinase (JAK) and signal transducer and activator of transcription (STAT) molecules to transduce signals from the cell surface to the nucleus, where they regulate transcription. This pathway is basically involved in almost all inflammatory diseases and also in the interleukin (IL)-23/IL-17 cascade, which is an essential part of the pathogenesis of spondyloarthropathies (SpA). Upon evidence from in vitro and in vivo experiments indicating disease-modifying effects of JAK inhibition in inflammatory joint disease, numerous inhibitors of the JAK/STAT pathway (= JAKinibs) with different selectivity against the four members of the JAK family [JAK1, JAK2, JAK3, and tyrosine kinase 2 (TYK2)] were developed. Trials in rheumatoid arthritis were successful with respect to efficacy and safety, and currently, three JAKinibs are approved for the treatment of rheumatoid arthritis in the European Union. Although new treatment options (anti-IL-23, anti-IL-17, and phosphodiesterase 4 inhibitors) have become available for spondyloarthritis and especially psoriatic arthritis (PsA) within the last years, most of them are biologics and do not address all disease manifestations equally. Therefore, multiple trials were initiated to evaluate JAKinibs in PsA and axial spondyloarthritis (axSpA). A trial of Tofacitinib (OPAL) was successful in PsA and has led to the inclusion of JAKinibs into the treatment algorithm. Currently many trials with JAKinibs are ongoing for PsA and axSpA, with one phase III trial of upadacitinib (selective JAK1 inhibitor) showing good therapeutic response in active radiographic axSpA.