After six months, patients with psoriatic arthritis who are treated with the anti-tumor necrosis factor-alpha monoclonal antibody adalimumab continued to maintain their improvement when compared to treatment with placebo.

Physician presented results of the 24-week evaluation of the Adalimumab Effectiveness in Psoriatic Arthritis Trial (ADEPT) on February 19th at the 63rd annual meeting of the American Academy of Dermatology. At this point in the trial, 67% of patients treated with adalimumab were “clear” or “almost clear” of psoriasis, compared with 10% of patients who were taking placebo.

“This phase 3 trial demonstrated that adalimumab treatment was efficacious in treating the signs and symptoms of psoriatic arthritis,” said Philip Mease, MD, clinical professor and rheumatologist at the University of Washington in Seattle, Washington. “Adalimumab treatment was well-tolerated, with a similar safety profile as that observed with rheumatoid arthritis.”

Dr. Mease said that researchers believed that because tumor necrosis factor is present in increased concentrations in patients with psoriatic arthritis - an inflammatory arthropathy that consists of skin and joint manifestations - that adalimumab could effectively intervene in the pathogenesis of the disease. In the study, patients were treated with adalimumab 40 mg through subcutaneous interjections every other week.

In the ADEPT 12-week analysis, 60% of patients were determined as being “clear” or “almost clear” when the standard evaluation tool, the physicians global assessment, was employed compared with 3% for patients given placebo. That difference - as well as the difference at 24 weeks - was statistically significant at the P<.001 level, he said.

In a poster presentation, Dr. Mease also said that the percentages of patients with higher ACR (American College of Rheumatology) 20, ACR 50, and ACR 70 responses at week 12 were maintained through week 24. At 24 weeks, 57% of patients on adalimumab had achieved an ACR 20 versus 15% of those on placebo; 39% of patients on adalimumab achieved an ACR 50 versus 6% of those on placebo; and 23% of patients on adalimumab had achieved an ACR 70 versus 1% of those on placebo.

Patients on adalimumab also scored better than those receiving placebo on the Health Assessment Questionnaire Disability Index, Dr. Mease said.

“These are really terrific results for psoriatic arthritis,” said Phoebe Rich, MD, clinical associate professor of dermatology at the Oregon Health Sciences University, in Portland, Oregon. “These biological agents are proving to be good drugs in treating these disorders.”

[Study title: Adalimumab in psoriatic arthritis: 24-week results of a phase III study. Abstract P6]