Alefacept (Amevive) is an immunosuppressive dimeric fusion protein that is used for psoriasis control. We recently showed its effect in acute steroid-resistant/dependent GVHD. In this study, we describe the effect of alefacept treatment on chronic extensive GVHD (cGVHD). Twelve patients were included in this study; of these 8 (9 of 13 episodes) showed response. The median time to initial response was 2.25 weeks and the response was marked (n=3), moderate (n=2) or minimal (n=4). In two responding patients, the response was only temporary. Complications that appeared during treatment included infection, pericarditis and squamous cell carcinoma of the lip. All these events may be related to other drugs given simultaneously. With a 30-month median follow-up, 6 of 12 patients are alive, with all but one with stable or improved cGVHD. Six patients died because of GVHD progression, whereas none of the patients experienced relapse of the disease for which the transplantation was done. As reported earlier in psoriatic patients treated with alefacept, we found a consistent increase in the percentage of naive T cells as a consequence of treatment. In conclusion, alefacept is effective for the treatment of cGVHD, and dose and time intervals of treatment should be explored further.