The addition of a single course of alefacept to methotrexate therapy was effective in treating psoriatic arthritis in a clinical study, and an open-label extension has found further treatment with alefacept to extend the benefit in some patients. In the open-label extension, patients receiving stable doses of methotrexate were given an additional 12 weekly intramuscular injections of alefacept and were observed for another 12 weeks. At the end of the extension, an ACR20 response was achieved by 86 of 160 patients (54%); responders including 28 patients who had previously been given placebo plus methotrexate and 58 patients who had previously been given alefacept plus methotrexate. A second course did not increase the ...