Comparison of Tacrolimus and Sirolimus (Tac/Sir) versus Tacrolimus Sirolimus and mini-methotrexate (Tac/Sir/Mtx) as Acute GVHD Prophylaxis after Reduced Intensity Conditioning Allogeneic Peripheral Blood Stem Cell Transplantation

摘要

Previous studies have shown that the addition of sirolimus to tacrolimus/mini-methotrexate (tac/sir/mtx) as GVHD prophylaxis produces low rates of acute GVHD after reduced intensity (RIC) allogeneic SCT. To assess whether the post transplant methotrexate can be safely eliminated altogether, we conducted a prospective clinical trial testing the combination of tacrolimus and silrolimus (tac/sir) alone as GVHD prophylaxis after RIC SCT from matched related donors. We compare the results with patients who received tac/sir/mtx as GVHD prophylaxis after RIC SCT from matched related donors in a previous prospective study. Patients on both trials received fludarabine 30 mg/m²/d IV and intravenous busulfan 0.8 mg/kg/d IV from day −5 through day −2 as conditioning, followed by transplantation of unmanipulated filgrastim mobilized peripheral blood stem cells. Both cohorts received tacrolimus and sirolimus orally starting on day-3, with doses adjusted to achieve trough serum levels of 5–10 ng/ml and 3–12 ng/ml, respectively. The tac/sir/mtx cohort received additional mini-methotrexate (5 mg/m2 IV) on day +1,3,6. Filgrastim 5 mcg/kg SC QD was started on day +1 until neutrophil engraftment. Twenty nine patients were transplanted on tac/sir, and 46 were transplanted on tac/sir/mtx. The two groups were balanced in age, gender, and disease characteristics. Engraftment was brisk and donor chimerism after transplant was robust in both groups. The cumulative incidence of grade II–IV acute GVHD were similar, 17% vs 11% for the tac/sir and tac/sir/mtx cohorts, respectively (p=0.46). There was also no difference in cumulative incidence of extensive chronic GVHD, treatment related mortality, disease relapse, or survival. The GVHD prophylaxis combination of tacrolimus and sirolimus is well tolerated, and is associated with a low incidence of acute GVHD in matched related donor RIC transplantation. The omission of mini-methotrexate from the tacrolimus and sirolimus GVHD prophylaxis combination does not appear to impact adversely on the development of acute GVHD.