Treatment with the relatively new drug Raptiva for 12 weeks has been shown to be a safe and effective treatment for moderate-to-severe chronic psoriasis. Now, new research indicates that the benefits are even more pronounced, without an increase in side effects, when therapy is extended to 24 weeks.

The study was sponsored by Genentech, Inc., which markets as Raptiva, known technically as efalizumab.

The findings, which appear in the Archives of Dermatology, are based on a study of 516 psoriasis patients who were given weekly injections of efalizumab or an inactive placebo for 12 weeks, and then efalizumab for 12 additional weeks.

After the first 12 weeks, the proportion of efalizumab-treated patients who achieved a 75% or 50% or greater improvement on a standardized psoriasis severity score was 26.6 percent and 58.5 percent, respectively.

By the 24th week, these numbers had improved to 43.8 percent and 66.6 percent, Dr. Alan Menter, from the Texas Dermatology Research Institute in Dallas, and colleagues report.

Moreover, improvements in symptom scores were maintained throughout the full study period.

There was no evidence of accumulating toxicity during the extension phase of the study, and the rate of reported adverse effects actually fell during the last 12 weeks.

“A longer-term (36-month) maintenance study currently under way will further define the ability to use continuous efalizumab therapy for this lifelong chronic disease,” the researchers note.

SOURCE: Archives of Dermatology, January 2005.