April 9 (HealthDay News) -- The drug golimumab shows promise in treating psoriatic arthritis, according to a new study. Psoriatic arthritis affects about 11 percent of people with psoriasis.

The University of California, San Diego-led study included 405 patients who still had active psoriatic arthritis after taking anti-rheumatic drugs or nonsteroidal anti-inflammatory drugs. The patients were randomly selected to receive injections of either 50 or 100 milligrams of golimumab or placebo every four weeks for 24 weeks.

The phase 3 study found that 51 percent of patients in the 50-mg group, 45 percent of those in the 100-mg group, and 9 percent of those in the placebo group achieved the American College of Rheumatology 20 percent improvement criteria (ACR20) by week 14. The improvements were in areas such as swollen and tender joints, pain, disease activity, physical function, and levels of C-reactive protein.

In addition, more patients in the 50-mg or 100-mg golimumab groups achieved ACR50 and ACR70 responses than those in the placebo group. Golimumab also improved psoriasis symptoms. Only 3 percent of patients in the placebo group achieved at least a 75 percent improvement in psoriasis symptoms, compared with 40 percent of those in the 50-mg golimumab group and 58 percent of those in the 100-mg golimumab group.

A small number of patients who received the drug experienced injection site reactions, and most of them were mild, the researchers said.

The study appears in the April issue of the journal Arthritis & Rheumatism.

Golimumab is a human monoclonal antibody designed to block signaling molecules that induce inflammation. A study released last year found that golimumab eased rheumatoid arthritis symptoms and even put some patients into remission.

SOURCE: Arthritis & Rheumatism, news release, April 6, 2009