JAK Inhibitor Tofacitinib Slows Progression in RA

The JAK inhibitor tofacitinib (Xeljanz), approved last November for treatment of rheumatoid arthritis, effectively inhibits structural progression and joint damage, in results of a 12-month interim analysis as part of a phase III study.

The phase II part of the study showed “sustained efficacy and manageable safety” for tofacitnib during two years of treatment either with or without methotrexate. However, the effects of the drug on structural disease progression have not been demonstrated until now. During the phase III trial, all patients are on a stable dose of methotrexate.

The study compares numerous outcomes among three groups, patients taking 5 mg or 10 mg twice daily in addition to methotrexate, and those taking placebo. Patients in the higher-dose group showed significantly less radiographic progression than those on placebo after 6 months. The difference was not significant for the 5 mg group, perhaps because patients on placebo were allowed to switch to the drug after 3 months.

Significant differences in ACR20 and ACR50 response between both treatment groups and placebo were evident at 6 months, although disability scores were significantly superior only for the 10 mg group.

After 12 months, more than 85% of both treatment groups showed no progression, compared with 74% in the placebo group.