Catherine Faucher

Reduced-intensity conditioning (RIC) regimens are increasingly used for allogeneic stem cell transplantation (allo-SCT). RIC has been shown to allow engraftment with minimal early transplantation-related mortality (TRM). However, in the context of RIC, predictive factors for acute and chronic graft-versus-host disease (aGVHD and cGVHD, respectively) and their effect on outcome remain unknown. In this report, we analyzed the outcome of 101 high-risk patients (70 hematologic and 31 nonhematologic malignancies) who received an HLA-identical sibling allo-SCT after RIC, including fludarabine, busulfan, and antithymocyte globulin (ATG). The cumulative incidence of grade II-IV aGVHD was 36% (95% confidence interval [CI], 27%-45%), whereas the cumulative incidence of cGVHD at 2 years was 43% (95% CI, 33%-53%). In multivariate analysis, the incidence of aGVHD was significantly associated with the ATG dose infused during conditioning (P =.0005), whereas peripheral blood as stem cell source was the only predictive factor for the development of cGVHD (P =.0007). The 1-year cumulative incidences of disease progression or relapse in patients with (n = 69) and without (n = 31) GVHD (whatever its form or grade) were 30% (95% CI, 19%-41%) and 55% (95% CI, 37%-72%), respectively (P =.02), suggesting that a potent graft-versus-tumor (GVT) effect can be achieved in high-risk patients following RIC. Moreover, the GVT effect was closely associated with GVHD without an increased risk of TRM (cumulative incidence of TRM, 18% [95% CI, 10%-25%]). Collectively, these results provide a framework for the refinement of RIC approaches designed to enhance the GVT effect with an acceptable risk of GVHD.

Recently, the administration of high-dose cyclophosphamide (Cy) after T cell-replete haploidentical stem cell infusion has been reported to be feasible and effective. In the original study, bone marrow (BM) was used as the source of stem cells. Here, we retrospectively analyzed the use of BM versus peripheral blood stem cells (PBSCs) in a cohort of patients receiving haploidentical T cell-replete transplantation after a nonmyeloablative conditioning regimen with postinfusion Cy. In the PBSC versus BM groups, the incidence of acute graft-versus-host disease (GVHD) was 33% versus 25%, respectively, and the incidence of chronic GVHD was 13% versus 13%, respectively. The median time to achieve a safe and unsupported absolute neutrophil and platelet count was 20 versus 21 days and 27 versus 29 days, respectively. The incidence of engraftment was also similar in the 2 cohorts. The 1-year nonrelapse mortality rate was 12% versus 22%, respectively (P = .96). Finally, nonsignificant differences in survival were observed. In conclusion, the use of PBSCs instead of BM after T cell-replete haploidentical transplantation did not appear to be detrimental in terms of either GVHD or engraftment rate. PBSCs could be a valid alternative to BM after transplantation from a haploidentical donor using postinfusion Cy.