Pharmaceutical company, Pfizer Inc., announced recently that the U.S. FDA approved the first (and only) Janus kinase inhibitor for treating severe psoriatic arthritis (PsA). Called XELJANZ® and XELJANZ® XR, this medication will be used in patients that have experienced an intolerance or inadequate response to other drugs, such as methotrexate and antirheumatics.
The approval comes after successful clinical trials in psoriatic arthritis patients. In fact, in two studies of XELJANZ® (OPAL Broaden and OPAL Beyond) found that compared to placebo, patients taking XELJANZ® achieved statistically significant improvements in the American College of Rheumatology 20 Response and the Health Assessment Questionnaire-Disability Index.
XELJANZ® works by inhibiting the activity of one or more of a group of enzymes known as Janus kinase. This interferes with signaling pathways that contribute to autoimmune disorders, such as psoriatic arthritis.