Therapy of steroid-refractory acute GVHD with CD52 antibody alemtuzumab is effective

The efficacy and safety of CD52 antibody alemtuzumab to treat severe acute GVHD in 18 consecutive patients refractory to standard high-dose corticosteroid therapy is reported. Patients (age range 13-68 years) had developed acute GVHD grade III and IV with gut and/or liver involvement after stem cell transplantation from family donors (n= 7) or HLA-matched unrelated donors (n=11), including five donors with one or two HLA mismatches. Initially, in three patients, start doses of alemtuzumab in the range of 70-80 mg were applied and repeated after 3 to 4 weeks. Impressive responses were seen, but virus reactivation and bacterial infections were frequent. In an attempt to reduce this complication, the next nine patients received a reduced starting dose of 20-33 mg, and the last six patients received 3-13 mg repeated every 2-3 weeks. Seventeen of 18 patients responded to alemtuzumab, six patients are alive with a median follow-up of 108 weeks. Chronic GVHD was observed frequently. Although pronounced lymphocyte depletion requiring close monitoring for signs of infections seems inevitable for efficacy, alemtuzumab given in moderate doses has a substantial activity not only in intestinal but also in severe acute GVHD of the liver.