Pfizer’s Xeljanz (tofacitinib), used to treat conditions such as rheumatoid arthritis and ulcerative colitis, has encountered safety issues with the higher dose treatment arm of its post-marketing study of patients with cardiovascular risk factors.

The study is an ongoing, open-label, endpoint-driven study to evaluate the safety of Xeljanz at two doses  (10 mg twice daily and 5 mg twice daily) versus a tumor necrosis factor inhibitor (TNFi) control group. This study was designed to assess the risk of cardiovascular events, and patients were required to be at least 50 years of age and have at least one CV risk factor to be eligible for participation in this study. All patients entered the study on stable doses of background methotrexate.

As the result of notification from the tofacitinib Rheumatology Data Safety Monitoring Board (DSMB) of a safety signal regarding the tofacitinib 10 mg twice daily treatment arm, patients on the higher dose are being transitioned to 5 mg twice daily. The DSMB observed that the 10 mg patients had a statistically and clinically important difference in the occurrence of pulmonary embolism, compared with study patients being treated with a TNFi. The DSMB also noted an increase in overall mortality in the 10 mg group compared to the 5 mg twice daily and TNFi treatment arms.