The U.S. Food and Drug Administration yesterday approved a new oral medication for rheumatoid arthritis, or RA. Tofacitinib, brand name Xeljanz (ZEL'jans), is for patients with moderate to severe rheumatoid arthritis who do not respond well to methotrexate, a disease-modifying antirheumatic drug, or DMARD. But even as the FDA cleared the way for the drug to be sold to patients, the agency cautioned that more studies are needed to track the long-term effects of the medication, which is the first of a whole new class of drugs.

Tofacitinib, made by Pfizer, is the first oral DMARD approved in more than a decade, and its effectiveness is being compared to biologic medications such as adalimumab, or Humira, etanercept, or Enbrel, rituximab, or Rituxan, and tocilizumab, or Actemra. Unlike biologics, which are given intravenously or injected, tofacitinib is in pill form, to be taken twice daily. Tofacitinib can be used alone or in combination with methotrexate.

Xeljanz provides a new treatment option for adults suffering from the debilitating disease of RA who have had a poor response to methotrexate,” according to Badrul Chowdhury, MD, PhD, director of the division of pulmonary, allergy and rheumatology products in the Food and Drug Administration’s Center for Drug Evaluation and Research.

Tofacitinib is part of a new class of drugs called JAK inhibitors, which work by blocking Janus kinase, or JAK, pathways involved in the body’s immune response. Tofacitinib fights inflammation from inside the cell, attacking a different part of the pathway than biologic agents, which block pro-inflammatory cytokines (proteins) – like tumor necrosis factor-alpha and interleukin-6 – from outside the cell.

“Most of the medicines out there target one specific cytokine, but tofacitinib has the potential to affect multiple cytokines,” explains Beth Jonas, MD, an associate professor of medicine at the Thurston Arthritis Research Center at the University of North Carolina at Chapel Hill. “Theoretically it might be more effective in controlling inflammation, although from the data available it doesn’t look like it’s better than other biologic therapies.”

But because tofacitinib has a new mechanism of action, it might help patients who don’t currently respond to biologics. “I have a subset of patients who have not responded remarkably well to any of the available therapies, so this will be the next medication to try,” Dr. Jonas says. “If you are on a drug that’s working well for you, I would not recommend switching, but if you have had an inadequate response to therapies out there, this may be something you need to talk with your doctor about.”

Other experts agree. “This isn’t a panacea. It isn’t for everybody. But for some people, the idea of an oral medication offers an advantage and an appeal,” says Eric Ruderman, MD, professor of medicine at Northwestern University's Feinberg School of Medicine in Chicago.

Pfizer says it will conduct long-term research on the drug’s effects. Current studies show benefits for patients in as little as two weeks.