Adding Adalimumab to Methotrexate Improves Outcome in Rheumatoid Arthritis

Laurie Barclay, MD

January 30, 2003

Jan. 30, 2003 — Addition of the recently approved monoclonal antibody adalimumab to methotrexate treatment for rheumatoid arthritis (RA) provided significant, rapid, and sustained improvement in disease activity, according to the results of a double-blind, placebo-controlled trial reported in the January issue of Arthritis & Rheumatism.

"Over the last decade, methotrexate has become the treatment of choice for RA," write Michael E. Weinblatt, MD, from Brigham and Women's Hospital in Boston, Massachusetts, and colleagues. "Even when they respond fully to methotrexate therapy, patients experience less than 50% improvement."

In the Anti-tumor Necrosis Factor Research Study Program of the Monoclonal Antibody Adalimumab (ARMADA) trial, 271 patients with active RA were randomized to receive injections of adalimumab (20 mg, 40 mg, or 80 mg subcutaneously) or placebo every other week for 24 weeks while continuing their long-term stable dosage of methotrexate.

The proportion of patients meeting American College of Rheumatology criteria for 20% improvement (ACR20) at 24 weeks was significantly greater in the adalimumab plus methotrexate groups (47.8% for 20 mg, 67.2% for 40 mg, and 65.8% for 80 mg) than in the placebo plus methotrexate group (14.5%; P < .001).

Compared with an ACR50 response rate of 8.1% in the placebo group, ACR50 response rates were also better in the groups receiving adalimumab (31.9% for 20 mg, P = .003; 55.2% for 40 mg, P < .001; and 42.5% for 80 mg, P < .001). ACR70 response rate was 4.8% in the placebo group, 26.9% in the 40-mg group ( P < .001), and 19.2% in the 80-mg group ( P = .02).

Most patients receiving adalimumab achieved an ACR20 response at the first scheduled visit (week 1). Numbers of adverse events were similar in all groups. Study limitations include absence of another active treatment arm to allow comparison of the response to adalimumab with that to other known therapies.

"The addition of adalimumab at a dosage of 20 mg, 40 mg, or 80 mg administered subcutaneously every other week to long-term methotrexate therapy in patients with active RA provided significant, rapid, and sustained improvement in disease activity over 24 weeks compared with methotrexate plus placebo," the authors write. "Our findings suggest that adalimumab may be a new therapeutic option for patients with longstanding, active RA who have had an inadequate response to methotrexate."

Abbott Laboratories and Knoll Pharmaceuticals supported this trial and have financial arrangements with some of the study authors.

Arthritis Rheum. 2003;48:35-45

Reviewed by Gary D. Vogin, MD


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