By retrospective analysis of 88 patients from the British Society of Blood and Marrow
Transplantation registry, we investigated the effect of in vivo T-cell depletion in HLA-identical sibling reduced-intensity conditioning (RIC) allografts for adult AML by comparing patients who received
alemtuzumab with those without
alemtuzumab conditioning. Both groups were equivalent for age, sex, karyotype and disease status at transplant. With a median follow-up of 27 months (3-72 months) and 48 months (7-72 months), the 2- and 5-year overall survival, with or without
alemtuzumab, is 60 and 60% (P=0.80) and 61 and 53%, respectively (P=0.85). The 2-year non-relapse mortality is 12% with
alemtuzumab, and 17% without
alemtuzumab (P=0.49). The 2-year relapse rate
is 35% with
alemtuzumab compared with 19% without
alemtuzumab (P=0.28). Grades II-IV acute GVHD occurred in 22% (8/37) without
alemtuzumab compared with 14% (7/51) given
alemtuzumab (P=0.25). Extensive chronic GVHD occurred in 47% (14/30) not given
alemtuzumab compared with 4% (2/45) who were given
alemtuzumab (P=0.001). Among evaluable patients, the risk of
infections was higher in those treated with
alemtuzumab compared with those not treated with
alemtuzumab (79 vs 57%, respectively, P=0.02). In conclusion,
alemtuzumab has a beneficial effect by reducing chronic GVHD without affecting overall survival. Further studies are warranted before
alemtuzumab can be recommended as standard in RIC allografts for AML.