Pfizer Xeljanz and Xeljanz XR have received US marketing clearance for the treatment of adults with active psoriatic arthritis (PsA) who have failed to respond or are intolerant to methotrexate or other disease-modifying antirheumatic drugs (DMARDs).

The decision means that the drug is now the first and only Janus kinase (JAK) inhibitor approved by the US Food and Drug Administration for both moderate to severe rheumatoid arthritis (RA) and active PsA, the drug giant highlighted.

Approval came after two Phase III trials assessing Xeljanz (tofacitinib) - OPAL Broaden and OPAL Beyond – hit their primary efficacy targets, showing statistically significant improvements in American College of Rheumatology 20 (ACR20) response and change from baseline in the Health Assessment Questionnaire–Disability Index (HAQ-DI) score.

In OPAL Broaden, 50 percent of patients taking Xeljanz 5mg twice daily achieved an ACR20 response compared to 33percent of patients in the placebo arm, while in OPAL Beyond, 50 percent of patients achieved an ACR20 response with Xeljanz 5mg twice daily compared to 24 percent of those given a placebo.

Pfizer also noted that in both studies, statistically significant improvements in ACR20 response were recorded in the treatment arm versus placebo at week two, thereby meeting a secondary endpoint.

On the safety side, it was reported that the side effects seen in patients with active psoriatic arthritis treated with Xeljanz were consistent with those observed in rheumatoid arthritis patients, the most common being nasopharyngitis, upper respiratory tract infection, headache and diarrhoea.

“As a practicing rheumatologist, I’ve seen the significant physical impact psoriatic arthritis has on people living with the disease, and many patients are looking for additional therapeutic options,” said Philip Mease, Swedish Medical Center, University of Washington and study investigator. “I’m pleased that Xeljanz is now available for use in the treatment of this chronic condition.”

The drug was cleared in the EU for the treatment of RA earlier this year, having initially been turned down by European Medicines Agency advisors back in 2013 on grounds that it "did not believe that a consistent reduction in disease activity and structural damage to joints had been sufficiently demonstrated".