Clinical differences in baricitinib and tofacitinib effectiveness in rheumatoid arthritis
medwireNews: Patients with rheumatoid arthritis (RA) may derive better clinical outcomes from baricitinib than tofacitinib in the first 24 weeks of treatment, especially if they have previously received multiple biologic (b)DMARDs, show real-world data.
“Results suggest that [tofacitinib] may be less effective in patients resistant to multiple bDMARDs, while [baricitinib] may be more effective after 24 weeks of treatment,” say Yoshiya Tanaka and co-researchers, from the University of Occupational and Environmental Health in Kitakyushu, Japan.
They analyzed data from 294 Japanese patients with RA recruited to the FIRST registry who had been given baricitinib (n=138) or tofacitinib (n=156) following nonresponse or intolerance to methotrexate or conventional DMARDs. Propensity score-based inverse probability of treatment weighting was used to reduce selection bias to a minimum.
At 24 weeks, a significantly greater proportion of baricitinib- than tofacitinib-treated patients achieved low disease activity, at 81.6% versus 69.3% according to CDAI, and 81.5% versus 69.9% as measured by SDAI.
The corresponding CDAI and SDAI remission rates were also significantly higher with baricitinib than tofacitinib, at 40.4% versus 28.3% and 45.4% versus 34.0%, respectively.
The researchers report that patients in the baricitinib group were 70% more likely to achieve CDAI remission than those in the tofacitinib group, but they caution: “Although the CDAI numerical values displayed statistical differences, the differences in numerical values were small and may not be clinically meaningful.”
The rate of HAQ-DI remission was similar for the baricitinib and tofacitinib treatment groups (44.7 and 44.4%, respectively) at 24 weeks, but the study authors emphasize that “the duration of the analysis might have been too short for differences to be observed.”
Regardless of the superior effectiveness seen with baricitinib compared with tofacitinib, both Janus kinase inhibitors significantly reduced patients’ disease activity (measured by CDAI and SDAI), disability (HAQ-DI), C-reactive protein levels, and erythrocyte sedimentation rate, with improvements first seen after 2 weeks of treatment.
However, further analysis identified a treatment-resistant group of patients with high disease activity at baseline who did not achieve low disease activity by week 24, with only partial or limited responses to treatment. Patients given tofacitinib were more likely to be treatment resistant than those given baricitinib (odds ratio [OR]=2.13).
Treatment resistance was also significantly associated with baseline HAQ-DI score (OR=1.76) and number of prior biologic treatments (OR=1.51), according to multivariate analysis. But when the researchers looked at the two treatment groups separately, they found that a higher number of prior biologics, based on a cutoff of four, only remained a significant factor for treatment resistance among patients taking tofacitinib, whereas there were no factors significantly associated with treatment resistance among those taking baricitinib.
Overall, Tanaka et al observed that there was a “similar safety profile” between the two treatments, with no significant differences in the rate of serious adverse events, at 2.9% among patients taking baricitinib and 6.4% among those given tofacitinib. This included serious infections in 1.5% versus 1.3% of patients, respectively. Retention rates were also comparable between the baricitinib and tofacitinib group (91.5 vs 86.9%).
The study investigators conclude in the Annals of the Rheumatic Diseases: “These results were observed in a relatively small group of patients and were obtained on hypothesis testing; accordingly, they need to be investigated in an accurately powered head-to-head trial.”
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