Reduced Intensity Versus Conventional Myeloablative Conditioning (RIC vs. MAC) Allogeneic Stem Cell Transplantation (allo-SCT) for Patients with Acute Lymphoblastic Leukemia (ALL): A Survey from the Acute Leukemia Working Party of EBMT

The exact role of RIC allo-SCT for adult patients with ALL is still under considerable debate. While the use of such so-called nonmyeloablative or RIC regimens has emerged as an attractive modality to decrease transplant-related mortality, toxicity might represent only one aspect of the problem, since ALL encompasses a group of chemosensitive diseases, raising concerns that significant reduction of the intensity of the preparative regimen may have a negative impact on long-term leukemic control. In this multicenter retrospective study, the outcomes of 601 adult (age at transplantation >45 y.) patients with ALL who underwent transplantation in complete remission (CR) with an HLA–identical sibling donor, were analyzed according to 2 types of conditioning: RIC in 97 patients, and standard MAC (or high-dose) in 504 patients. Both groups were comparable in terms of gender, CR status (CR1 and CR2), interval from diagnosis to allo-SCT, and recipient/donor CMV serostatus. Patients in the RIC groups were older (median 56 y. vs. 50y in the MAC group; P 45 y.) may represent a valid therapeutic option when a conventional standard conditioning is not possible, warranting further prospective investigations.