Rheumatoid arthritis an autoimmune disease in which the body s immune system mistakenly attacks healthy tissue, gradually destroying the body s joints affects an estimated 1.5 million Americans, with an estimated 30 to 40 percent of them beyond the help of available drugs. But new hope may be on the horizon with the Food and Drug Administration granting approval for Pfizer Inc s Xeljanz as a new form of oral treatment.
The new drug, also known by its chemical name tofacitinib, has been approved for patients with moderate to severe RA who have had inadequate responses or not been able to tolerate the more standard oral treatment, including methotrexate. The twice-daily pill works by blocking the pro-inflammatory enzymes known as Janus kinases, which are linked to joint inflammation.
The approval comes after two large studies published in the New England Journal of Medicine showed that between one-half to two-thirds of the study patients receiving tofacitinib has at least a 20 percent improvement in their joint symptoms and clinical signs, while only a little over one-quarter of those receiving a placebo showed that much improvement. While this benefit may seem less than overwhelming, the enthusiastic acceptance of Xeljanz makes it clear how difficult it is to control RA, even using new and powerful medications that have been introduced over the past decade.
Overall, tofacitinib s safety and effectiveness has been evaluated in seven clinical trials and has shown side effects of increased risk for serious infections, tuberculosis, cancers and lymphoma. The FDA did address the associated risks, stating that it approved the drug with a risk evaluation and mitigation strategy, requiring safety information on the drug's package insert label and a communication plan to inform healthcare providers and their patients about its risks.
This is a serious breakthrough, says ACSH s Dr. Ruth Kava. With increased risk of infection and lymphoma, the approval of tofacitinib may be an indicator of a slight relaxation in the FDA s drug approval process; furthermore, the fact that this drug is an oral inhibitor of the Janus kinase pathway makes it a completely new approach to RA treatment.
Indeed it is a novel approach, ACSH s Dr. Gilbert Ross agreed. Janus kinase inhibitors are already being used for certain cancer treatments such as ovarian and fallopian tube cancers, I m sure we will be reading more on other diseases Janus kinase inhibitors are treating. This oral treatment can be useful for those RA sufferers who fail to respond or can t tolerate one of the several injection immunosuppressives which have almost revolutionized treatment of this painful and disabling disease.