Improved outcomes using tacrolimus/sirolimus for graft-versus-host disease prophylaxis with a reduced-intensity conditioning regimen for allogeneic hematopoietic cell transplant as treatment of myelofibrosis.

Allogeneic hematopoietic cell transplantation (HCT) using reduced-intensity conditioning (RIC) regimens is a potentially curative treatment for patients (patients) with myelofibrosis (MF), as we and others have reported. Nonrelapse mortality (NRM) from graft-versus-host disease (GVHD) and other complications has limited the success of this approach. As part of an ongoing prospective research study at City of Hope, a combination of tacrolimus/sirolimus +/- methotrexate (MTX) for GVHD prophylaxis has become the standard treatment for our allogeneic HCT patients. In this report, we present results for 23 consecutive patients, including extended follow up for 9 patients previously reported who received cyclosporine (CsA)/mycophenolate moffetil (MMF)+/-MTX, and the current series of 14 patients who received tacrolimus/sirolimus+/-MTX, and evaluate the impact of the GVHD prophylaxis regimen on the outcomes. Median follow-up for alive patients was 29.0 months (9.5-97.0). The estimated 2-year overall survival (OS) for the CsA/MMF cohort was 55.6% (confidence interval 36.0, 71.3), and for the tacrolimus/sirolimus cohort it was 92.9% (63.3, 98.8) (P=.047). The probability of grade III or IV acute GVHD (aGVHD) was 60% for the CsA/MMF patients, and 10% for the tacrolimus/sirolimus group (P=.0102). No significant differences were seen for grade II to IV aGVHD in the 2 groups. We conclude that the combination of tacrolimus/sirolimus+/-MTX for GVHD prophylaxis in the setting of RIC HCT for MF appears to reduce the incidence of severe aGVHD and NRM, and leads to improved OS compared to CSA/MMF+/-MTX.