Final results reported from phase 3b study of efalizumab; Data support long-term efficacy and safety

Results from a 36-month, open label study demonstrate the efficacy and safety of continuous treatment with efalizumab (Raptiva, Genentech) in adults with moderate-to-severe chronic plaque psoriasis, reports Craig L. Leonardi, M.D.

Patients could enroll to participate in the maintenance treatment study if they achieved a Psoriasis Area and Severity Index (PASI) improvement of at least 50 percent (PASI-50) or static Physician's Global Assessment grading of "mild," "minimal," or "clear" after 12 weeks of once weekly subcutaneous 2 mg/kg. Of 339 patients who began the trial, 290 entered the maintenance phase during which they received efalizumab 1 mg/kg per week. A total of 146 patients completed 33 months of maintenance therapy.

Analyses performed at three-month intervals showed patients maintained the treatment benefit over time, while efalizumab continued to be well-tolerated and was not associated with new adverse events as the duration of use increased.

Among the patients who started the maintenance phase, 51 to 56 percent were PASI-75 responders throughout the follow-up. Considering only patients still on therapy at each assessment showed PASI-75 response rates ranged up to 75 percent toward the end of the study.

At week 12, 13 percent of the original 339 patients were PASI-90 responders. However, that proportion increased over time, demonstrating a benefit for continued improvement with longer therapy. At last visit, 40 percent of patients on therapy were PASI-90 responders.

Rates of patient withdrawals for adverse events remained consistently low throughout the study, no new common adverse events emerged, and there was no evidence of cumulative or end-organ toxicity.

"This is the longest continuous study of psoriasis patients on a biologic therapy, and Genentech, the industry sponsor, should be applauded for making the commitment to showing us how to use efalizumab over the long-term. Efalizumab is a chronic therapy for a chronic inflammatory disease, and was shown in this group of patients that it could be used continuously and safely," says Dr. Leonardi.