FDA Approves New Drug for Rheumatoid Arthritis
Xeljanz, or tofacitinib, is the first of a new class of drugs.
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.
Two separate phase III studies funded by Pfizer were published in August in the New England Journal of Medicine. In a six-month trial of 611 patients, both the 5 mg and 10 mg doses taken twice a day were more effective than placebo. And a yearlong study of more than 700 patients who had an inadequate response to methotrexate, patients taking 5 mg or 10 mg of tofacitinib twice a day had comparable improvement in symptoms to those taking adalimumab, and showed more improvement than those on placebo.
The Food and Drug Administration approved the 5 mg dose of tofacitinib.
“It’s exciting to have a new drug that might be beneficial for people with rheumatoid arthritis, but we have a lot yet to learn,” says Patience White, MD, vice president for public health at the Arthritis Foundation and professor of medicine and pediatrics at George Washington University School of Medicine in Washington, D.C.
Many doctors and pharmacists agree, but caution that like all drugs, there are serious side effects to consider with tofacitinib. “People are often looking for the magic bullet, saying, ‘I hope this is the breakthrough and the drug with no side effects,’ and I would put cold water on that,” says pharmacist Donald Miller, professor and chair of the pharmacy practice department at North Dakota State University in Fargo. “It’s always nice to have different drugs available but it [won’t] necessarily be more effective or safer than the drugs already out there.”
Potential side effects include an increased risk of cancer; increased risk of serious infections including tuberculosis, pneumonia and upper respiratory tract infections; neutropenia, a condition marked by a very low white blood cell count that makes it hard to fight infection; increases in cholesterol levels and elevated liver enzymes.
Dr. White says that even though studies have outlined these side effects in clinical trials of a few thousand people, because tofacitinib is in a new class of medications, there’s no track record of similar medications to better understand how it will affect a wider group of patients.
“It’s always exciting when we make advances, and it is good to have many options. But there is a caveat of caution when we have a new drug. We don’t want to jump with our eyes closed,” Dr. White explains. “This is a whole new antibody. We don’t necessarily know all the things that it does.”
That’s why, in the short term at least, Dr. Ruderman says most rheumatologists, including him, are unlikely to use tofacitinib as a first-line drug.
“We are 10 years down the road with [TNF-alpha] inhibitors, and we are finally getting our arms around what the side effects are,” Dr. Ruderman says. “You don’t always know that after the clinical trials. A lot of that comes after the medication is on the market and a large number of patients take it. So I think a lot of rheumatologists will hang back and get a better feel for it once it’s on the market a while.”
Terry Moore, MD, director of the division of rheumatology at St. Louis University agrees, and says only time will tell where this new medication fits into the overall medical regimen.
“You have to deal with its cost and where insurance companies will put it on their priority list,” Dr. Moore says. “Leaving that aside, it probably will be used after methotrexate and maybe after a biologic you are familiar with. Maybe then you would go to this medication.”