EULAR: Rheumatoid Arthritis Response Quicker to Certolizumab

BARCELONA, Spain, June 15 -- Rheumatoid arthritis responds more quickly to investigational certolizumab pegol (Cimzia) than to other tumor necrosis factor-a inhibitors, researchers have found.

Two thirds of RA patients respond within two weeks and almost half have a 50% reduction in symptoms by 24 weeks, according to Ed Keystone, M.D., of the University of Toronto.

"Usually, other (TNF-a) inhibitors plateau at about 24 to 36 weeks, Dr. Keystone said during the European League Against Rheumatism (EULAR) meeting here. "This plateaus at 16 weeks, which means earlier, more robust response or the same robust response achieved earlier."

Dr. Keystone presented preliminary results of a 52-week, placebo-controlled trial of the investigational drug, which combines the TNF-a inhibitor with polyethylene glycol.

The resulting pegylated molecule lasts longer in the bloodstream and may have selective accumulation in inflamed joints, Dr. Keystone said. It also does not cross the placental barrier or get into breast milk, making is safer for women of child-bearing age.

In the study, patients whose disease was not responding to methotrexate (Rheumatrex, Trexall) were randomized to placebo or 200 mg or 400 mg of subcutaneously certolizumab pegol every two weeks.

All participants in the 982-patient industry-supported RAPID-1 study continued to take methotrexate, Dr. Keystone said.

Patients who did not have at least a 20% reduction in symptoms at week 16 -- the so-called ACR 20 -- were transferred to a rescue arm, an open-label study of 400 mg of certolizumab pegol. Patients who dropped out of the study for any reason were considered non-responders.

In 24-week results, Dr. Keystone reported:

• 13.5% of patients taking methotrexate only (the placebo arm) achieved an ACR 20 response, compared with 59.2% and 61.2% for 200 and 400 mg of certolizumab, respectively.
• The corresponding results for a 50% reduction in symptoms were 7.5%, 37.5%, and 40.6%.
• The results for a 70% reduction in symptoms were 3%, 21.4%, and 20.7%.
• All comparisons with placebo were statistically significant at P