New Rheumatoid Arthritis Drug in the Works

Researchers Report Relief From RA Symptoms for Patients Taking Masitinib

From the WebMD Archives

June 29, 2009 -- An experimental drug called masitinib may ease rheumatoid arthritis symptoms in people who aren't helped by other drugs, a new study shows.

That study, published online in Arthritis Research & Therapy, included 40 adults in France who had rheumatoid arthritis (RA) that didn't respond to other RA drugs.

For 12 weeks, the patients took masitinab tablets twice daily at various doses. Patients whose RA eased during that time could opt to continue masitinib treatment.

Masitinib targets immune system cells called mast cells. The goal is to interrupt a chain reaction of inflammatory chemicals that may contribute to rheumatoid arthritis. Masitinib is also being studied as a cancer drug.

Roughly half of the patients had their RA symptoms ease during the study.

Almost all of the patients -- 95% -- reported some adverse event during the study. Most adverse events were mild to moderate and temporary, such as rashes, swelling, nausea, and diarrhea.

Four patients had severe adverse events (skin rash, pneumonia, fluid buildup near the lungs, and RA flare-up), and 37% of all patients quit the study because of adverse events.

Adverse events were most common during the first month of masitinib treatment, and overall, the researchers considered masitinib to have a "favorable" profile for longer-term treatment. They're still working on finding the optimal dose of the drug that will be effective but limit side effects.

The study was sponsored by AB Science, the drug company that's developing masitinib. Several of the researchers are AB Science employees.

WebMD Health News Reviewed by Louise Chang, MD on June 29, 2009



Tebib, J. Arthritis Research & Therapy, June 23, 2009; online edition.

News release, BioMed Central.

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