Immunomodulatory Effect of Vitamin D after Allogeneic Stem Cell Transplantation: Results of a Prospective Multicenter Clinical Trial.

Abstract

We describe the results of a prospective multicenter phase I/II trial evaluating the impact of the use of vitamin D (VitD) from day -5 to +100 on the outcome of patients undergoing allogeneic transplantation (EudraCT: 2010-023279-25; ClinicalTrials.gov: NCT02600988). A total of 150 patients were included in three consecutive cohorts of 50 patients each group: control group (CG, not receive VitD); low-dose group (LdD, received 1,000 IU VitD daily); and high-dose group (HdD, 5,000 IU VitD daily). We measured levels of VitD, cytokines, and immune subpopulations after transplantation. No significant differences were observed in terms of cumulative incidence of overall and grades 2-4 acute GVHD in terms of relapse, nonrelapse mortality, and overall survival. However, a significantly lower cumulative incidence of both overall and moderate plus severe chronic GVHD (cGVHD) at 1 year was observed in LdD (37.5% and 19.5%, respectively) and HdD (42.4% and 27%, respectively) as compared with CG (67.5% and 44.7%, respectively; P < 0.05). In multivariable analysis, treatment with VitD significantly decreased the risk of both overall (for LdD: HR = 0.31, P = 0.002; for HdD: HR = 0.36, P = 0.006) and moderate plus severe cGVHD (for LdD: HR = 0.22, P = 0.001; for HdD: HR = 0.33, P = 0.01). VitD modified the immune response, decreasing the number of B cells and naïve CD8 T cells, with a lower expression of CD40L. This is the first prospective trial that analyzes the effect of VitD postransplant. We observed a significantly lower incidence of cGVHD among patients receiving VitD. Interestingly, VitD modified the immune response after allo-SCT. Clin Cancer Res; 22(23); 5673-81. ©2016 AACR.