Tofacitinib showed superior efficacy and safety for treating adult patients suffering from ankylosing spondylitis.

A  randomized, phase III, double-blind, placebo-controlled trial was conducted to investigate the safety and efficacy of Tofacitinib (an oral Janus kinase inhibitor) for managing ankylosing spondylitis.

The study enrolled 269 adult patients (aged ≥ 18 years) diagnosed with active ankylosing spondylitis, who fulfilled the modified New York Criteria and had an inadequate or intolerant response to two or more nonsteroidal anti-inflammatory drugs (NSAIDs). Participants were randomly allocated to either tofacitinib (5 mg twice daily) group (n=133) or the placebo group (n=136) for 16 weeks. After the 16-week period, all subjects were administered open-label tofacitinib therapy until week 48.

The primary endpoint was therapy response at week 16, based on the Assessment of SpondyloArthritis International Society (ASAS) criteria; particularly, the proportion of subjects attaining a 20% improvement in ASAS response criteria (ASAS20). Investigators also assessed the proportion of patients attaining ASAS40 response (key secondary endpoint). Adverse events were monitored throughout the study.

At week 16, a higher proportion of responders in the tofacitinib arm attained ASAS20 and ASAS40 compared to the placebo arm, as illustrated in the following table:

Improvements in ASAS components were remarkably higher in the tofacitinib cohort compared to the placebo cohort, including Bath Ankylosing Spondylitis Functional Index score, morning stiffness, total back pain, and patient’s global assessment of disease activity.

Vital improvements were witnessed from week 2 (first post-baseline visit) in ASAS20 response and week 40 in ASAS40 response in tofacitinib-treated patients compared to placebo-treated patients. During the first 16 study weeks, adverse effects were reported by 72 (54.1%) in the tofacitinib arm and 70 (51.5%) patients in the placebo arm. The most usual adverse events occurring in patients treated with tofacitinib and placebo is depicted below:

Severe adverse events were witnessed in two patients treated with tofacitinib (1 hepatic event, 1 serious infection) and in no patients treated with placebo. However, no deaths were reported. Safety trends were found to be similar until week 48.

Ankylosing spondylitis patients showed a rapid clinical response to tofacitinib therapy. For primary and secondary endpoints, efficacy was substantially higher with tofacitinib compared to placebo. Although adverse events were more frequent with tofacitinib compared to placebo; but there were no novel safety risks.

Tofacitinib appears to be a promising therapeutic agent to manage ankylosing spondylitis patients.