SAN ANTONIO, Texas — Researchers said Tuesday that more than 70% of patients undergoing adalimumab treatment for psoriatic arthritis achieved dramatic improvement in their condition after 12 weeks of treatment.

"By 24 weeks of treatment, about 75% of patients had achieved a PASI (Psoriasis Area and Severity Index) 50 score," said Philip Mease, MD, Clinical Professor of Medicine at the University of Washington, Seattle. "We consider a PASI 50 the point at which patients experience substantial relief from symptoms."

Dr. Mease said researchers decided to treat psoriatic arthritis with adalimumab because tumor necrosis factor (TNF) is present in increased concentrations in the joints and skin of these patients. "Adalimumab is a TNF antagonist and we thought it had the potential to simultaneously impact both the skin and joint pain as well as the skin rash that affect these individuals," he said during his poster presentation at the 2004 annual meeting of the American College of Rheumatology (ACR).

In the ADEPT (Adalimumab Effectiveness in Psoriatic Arthritis Trial), doctors enrolled 313 patients: 151 were assigned to adalimumab; 162 received placebo. In the Phase III double-blind study, patients were injected with either placebo or 40 mg of adalimumab every other week for 24 weeks. The study was conducted in the United States, United Kingdom, Canada, France, Germany, Belgium and Austria.

To enter the trial, patients had to be adults, have at least 3 swollen joints and at least 3 tender joints, had to respond inadequately to nonsteroidal anti-inflammatory drugs, and have a history of psoriasis.

Dr. Mease said that in addition to reductions in the signs and symptoms of disease, the patients thought they were doing better on adalimumab than on placebo. Results of a Health Assessment Questionnaire (HAQ) disability index administered to patients showed a significant decline from baseline. "A mean change of 0.3 on the HAQ is considered meaningful," Dr. Mease said. In this trial, the decline was 0.4 points at 12 and 24 weeks.

On both the PASI and the standard ACR scales, patients also did significantly better than placebo at both 12 and 24 weeks. After 24 weeks, 75% of patients achieved a PASI 50 improvement; 59% achieved a PASI 75 improvement and 42% achieved a PASI 90 improvement.

"Those are just spectacular figures," said Hayes Wilson, MD, Medical Adviser to the Arthritis Foundation and Clinical Professor of Medicine at Morehouse School of Medicine, in Atlanta, Georgia. "It is really gratifying that we can produce these types of results. The anti-TNFs have a great promise in rheumatoid arthritis and they may even be better with psoriatic arthritis."

James Bozikis, Manager of Pharmaceutical Public Affairs for Abbott Laboratories, Abbott Park, Illinois, said the company plans to file for an indication for psoriatic arthritis for adalimumab with the Food and Drug Administration by the end of 2004.

References:

Mease PJ, Gladman DD, Ritchlin CT, et al. Adalimumab Therapy in Patients with Psoriatic Arthritis: 24-week Results of a Phase III Study. Presented at Annual Meeting of the American College or Rheumatology; October 19, 2004; San Antonio, Texas. Abstract L6/521.