Studies Back New RA Drug

March 20, 2008 -- Actemra, an experimental biologic drug, shows promise in treating rheumatoid arthritis and juvenile idiopathic arthritis (formerly called juvenile rheumatoid arthritis, or JRA).

That news comes from the drug's phase III trials, which test safety and effectiveness.  

Biologic drugs, such as Actemra, target specific parts of the immune system that lead the inflammation that causes joint damage in RA. Current biologic drugs used to treat RA include Enbrel, Humira, Orencia, Remicade, and Rituxan.

Actemra is not yet available. It works on a different area of the immune system than the other biologic drugs.

One trial covered rheumatoid arthritis; the other focused on juvenile idiopathic arthritis. Results for both trials appear in the March 22 edition of The Lancet.

A related editorial voices "cautious optimism" but calls for more studies on Actemra's possible effects on cholesterol, and for head-to-head comparisons of Actemra and other biologic arthritis drugs.

Rheumatoid Arthritis Study

The rheumatoid arthritis study included 621 patients with moderate to severe rheumatoid arthritis who had already tried the drug methotrexate for their RA.

The patients got injections of a higher dose of Actemra, a lower dose of Actemra, or a placebo every four weeks for six months.

At the end of the study, 59% of the patients who got the higher Actemra dose, 48% of those taking the lower Actemra dose, and 26% of those who got the placebo had at least a 20% improvement in their signs and symptoms of RA, which is considered significant improvement.

Upper respiratory tract infections were the most common side effects seen in the Actemra group. Liver enzyme levels also rose for some Actemra patients, but those were typically one-time events and weren't linked to symptoms of liver disease, according to the researchers.

Total cholesterol and LDL ("bad") cholesterol levels rose in the Actemra users. The reason for that isn't clear. Major heart "events" -- such as heart attacks -- weren't more common with Actemra use, but the study only lasted for six months, which may not have been long enough to detect cardiovascular risk.

WebMD reported on the study last June, when researcher Josef Smolen, MD, of Austria's Medical University of Vienna, presented the findings in Barcelona, Spain, at the European League Against Rheumatism's annual meeting.

The study, which didn't look at the drug's long-term safety, was funded by Hoffmann-La Roche and Japan's Chugai Pharmaceutical Co., which are developing Actemra.