Psoriasis responds to intralesional injections of alefacept and may predict systemic response to intramuscular alefacept: interim results of a single-arm, open-label study.

Background: Alefacept is a remittive treatment for generalized psoriasis but is rarely used due to its erratic efficacy.
Objective: To determine if psoriasis plaques will respond to intralesional alefacept and if this predicts a systemic response to intramuscular (IM) alefacept.
Methods: We describe a 25-week, single-center, open-label study. Patients received weekly intralesional alefacept of increasing concentrations into target plaques for 3 weeks followed by IM injections for 12 weeks and concluded with an observation period of 9 weeks. The psoriasis area and severity index (PASI) was used to assess the efficacy of IM alefacept.
Results: Interim results are reported for the first seven patients enrolled. Two patients responded intralesionally to the most dilute 1:100 concentration of alefacept to sterile water and achieved a 59% and 100% improvement in PASI. Five patients did not respond intralesionally to the most dilute form of alefacept and none achieved PASI 75. Two of these five patients did not respond to any concentration and achieved a 26% and 38% improvement in PASI. Limitations to this study include a small sample size and being non-placebo-controlled.
Conclusion: Alefacept is effective intralesionally and may predict a systemic response - challenging the concept that biologics must work systemically.