Background: A single course of alefacept intramuscularly in combination with methotrexate (MTX) was effective in treating both psoriasis and psoriatic arthritis (PsA).
Objective: We sought to determine the efficacy and safety of an additional course of alefacept intramuscularly in combination with MTX in patients with PsA.
Methods: In this open-label extension study, patients with PsA on stable doses of MTX were treated with an additional 12 weekly intramuscular injections of alefacept followed by 12 weeks of observation. Efficacy of PsA treatment was measured as 20% reduction in American College of Rheumatology criteria (ACR20).
Results: At the end of the open-label extension phase, 86 of 160 (54%) patients achieved ACR20, of which 28 of 55 had received placebo plus MTX and 58 of 105 received alefacept plus MTX in the prior double-blind phase. Although there was no increase in the proportion of patients achieving ACR20 after a second course of alefacept plus MTX, those achieving ACR50 and ACR70 increased from 17% and 7%, respectively, in the double-blind phase to 32% and 12%, respectively, in the open-label extension phase.
Limitations: In this open-label extension phase of the study there was no control group and the effect on psoriasis in these patients was not measured.
Conclusions: Patients with psoriasis and PsA on stable doses of MTX derive benefit for both conditions from one or more courses of alefacept, with further benefit in PsA apparent after a second course of treatment. No additional toxicity was observed.