WHISTLER, B.C. — Adalimumab was significantly more effective against psoriasis than both methotrexate and placebo were in a double-blind, double-dummy, randomized, controlled phase III trial, Dr. Richard Langley reported at a dermatology symposium.
The study is the first head-to-head comparison of a biologic and a standard systemic treatment for psoriasis, said Dr. Langley of Dalhousie University, Halifax, N.S., who participated in the multisite study. Dr. Langley has received funding to conduct the study from Abbott Laboratories, which manufactures adalimumab.
The Comparative Study of Humira vs. Methotrexate vs. Placebo in Psoriasis Patients included 271 patients with moderate to severe psoriasis from eight European countries and Canada. The patients were randomized into three groups to receive injections of adalimumab (108 patients), methotrexate (110 patients), or placebo (53 patients). The patient demographics were similar among the three groups.
The adalimumab group received the standard dosage given for other indications: a single subcutaneous injection of 80 mg, followed by a 40-mg subcutaneous injection every other week for 16 weeks.
After 16 weeks of treatment, 79.6% of the adalimumab patients achieved a Psoriasis Area and Severity Index (PASI) score of 75, which indicates a 75% reduction in symptoms of psoriasis. This improvement was statistically significant, compared with the other patients' scores: 35.5% of the methotrexate group and 18.9% of the placebo group achieved a PASI score of 75.
In addition, 88.0% of adalimumab patients achieved a PASI score of 50, compared with 61.8% of methotrexate patients and 30.2% of placebo patients, Dr. Langley reported.
Using the Physician's Global Assessment, psoriasis was judged to be clear or minimal in 73% of the adalimumab patients, compared with 30% of the methotrexate patients and 11% of placebo patients.
The mean methotrexate dosage was approximately 15 mg/kg by week 6, but it had been increased to approximately 20 mg/kg by week 12, whereas the adalimumab dose remained consistent, Dr. Langley noted.
The nature and incidence of adverse events were similar across the three groups. One placebo patient developed a kidney stone, one case of hepatitis occurred in a methotrexate patient, and one case of pancreatitis occurred in an adalimumab patient who had a history of heavy alcohol use, he said.
Nasopharyngitis was the most common of the adverse events that occurred in more than 5% of patients. Other reported adverse events included injection site reactions, hepatic events, arthralgia, and headache.
Adalimumab is currently approved in the United States for the treatment of adults with rheumatoid arthritis, psoriatic arthritis, and ankylosing spondylitis. Abbott plans to apply for a psoriasis treatment indication for adalimumab in the United States and Europe this year, Dr. Langley said.
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