May 26, 2011 -- An experimental drug called tofacitinib may help treat rheumatoid arthritis -- and it's taken as a pill, rather than as an injection or infusion.
In London, researchers reported results from a study in which rheumatoid arthritis (RA) patients took tofacitnib or a placebo. Tofacitinib improved symptoms better than the placebo and worked quickly in patients who had not responded to other medicines.
In the drug's study, side effects included infections, but most were mild, Kremer says. Four patients died during or after the trial, but the drug is not thought to be involved in most of those cases, and the researchers found the drug's safety profile to be "acceptable."
The results were presented at EULAR 2011, the Congress of the European League Against Rheumatism.
The new oral RA drug is in a class of drugs called JAK inhibitors. "It targets the disease in a unique manner," says researcher Joel Kremer, MD, the Pfaff Family Professor of Medicine and director of research at the Center for Rheumatology at Albany College in New York.
"It blocks molecules within the cell involved in signaling to promote inflammation," Kremer tells WebMD. "It works quickly and it's consistently effective."
Besides tofacitinib, which is being developed by Pfizer, several other JAK inhibitor drugs are in development by competitors.
According to the Arthritis Foundation, about 1.3 million Americans have RA. It is an inflammatory arthritis in which the immune system attacks the body's own tissues, especially the membranes lining the joints. Stiffness, pain, and disability can result.
Kremer's team studied 792 patients with RA for 12 months. None of the patients had responded to other RA drugs.
The researchers added on either the new drug or a placebo to the RA medications, such as methotrexate, that the patients were already taking.
At six months, 58% of the patients who took the higher of two doses of tofacitinib had a 20% improvement in tender or swollen joint counts. The patients also met three of five other criteria used to gauge improvement, such as an improved pain scale. Those taking the lower dose also showed improvement.
At the 12-month mark, nearly 37% of those in the higher-dose drug group had a 50% improvement. And 16% of those on the higher dose had a 70% improvement. In contrast, only 3% of those on placebo got the 70% improvement.
The drug's effects were seen after two weeks of therapy, according to the researchers.
In the drug's study, side effects included infections, but most were mild, Kremer says. As for the four deaths, Kremer says, "After reviewing all the source documents on this case, it appears to me that one of the four deaths could have been related to the drug." In a separate analysis, the researchers looked at 610 patients and found both doses had "clinically significant efficacy and acceptable safety."
Victoria Davis, a Pfizer spokeswoman, says the company plans to file for FDA approval for the drug by the end of 2011.