OBJECTIVES Higher MMF dose can reduce acute GVHD risk after allogeneic hematopoietic cell transplantation (HCT). We examined the effect of MMF dose, relative to patient actual body weight (mg/kg/day), on outcomes of 680 adults after HCT. METHODS MMF was combined with cyclosporine (n=599) or sirolimus (n=81). We divided MMF dose/kg/day in quartiles. RESULTS The median time to grade II-IV acute
GVHD was 32 days. The incidence of grade II-IV acute GVHD at day 30 was 30% in 1st (<29), 20% in 2nd (29-34), 16% in 3rd (35-41), and 19% in 4th (≥42) quartile (p<0.01). Corresponding relapse incidence at 1 year was 16%, 25%, 27%, and 31%, respectively (p=0.01). In multivariate analysis, as compared to 1st quartile, higher dose of weight-based MMF reduced grade II-IV acute GVHD (HR=0.64 for 2nd, HR=0.48 for 3rd, and HR=0.55 for 4th quartile), but increased the risk of relapse (HR=1.63 for 2nd, HR=1.75 for 3(rd) , and HR=2.31 for 4th quartile). CONCLUSIONS Weight-based MMF dose had no significant impact on engraftment, chronic GVHD or survival. These data suggest that higher weight-based MMF dose reduces the risk of acute GVHD at the expense of increased relapse and support conducting prospective studies to optimize MMF dosing after HCT.
