The FDA recently approved Xeljanz (tofacitinib) for the treatment of moderately to severely active rheumatoid arthritis (RA) in adults who have had an inadequate response to, or who are intolerant of, methotrexate. The decision comes ahead of the product's prescription drug user fee goal date of Nov. 21, 2012, the date the agency was scheduled to complete review of the drug application. Xeljanz, which is also under investigation for the treatment of psoriasis, is an oral agent that works by blocking molecules called “Janus kinases.” In trials evaluating the safety and efficacy of the agent, patients treated with Xeljanz experienced improvement in clinical response and physical functioning compared to patients treated with placebo. Xeljanz carries a boxed warning due to its association with an increased risk of serious infections, including opportunistic infections (infections that occur primarily when the immune system is suppressed), tuberculosis, cancers and lymphoma. Xeljanz treatment is also associated with increases in cholesterol and liver enzyme tests and decreases in blood counts.