Low rates of acute and chronic GVHD with ATG and PTCy in matched and mismatched unrelated donor peripheral blood stem cell transplants.

INTRODUCTION

We evaluated the combination of ATG and PTCy for GVHD prophylaxis in matched and mismatched unrelated PBSCTs for high-risk hematological malignancies.

METHODS

We treated 102 patients with reduced intensity conditioning (RIC) with fludarabine, busulfan, and TBI 200 cGy. GVHD prophylaxis included rabbit ATG (thymoglobulin at total dose of 4.5 mg/kg divided over days -3 to -1), PTCy (50 mg/kg/day on day +3 and on day +4), and cyclosporine. Clinical and outcome data were collected retrospectively.

RESULTS

Among 102 patients, 76 patients received 10/10 MUD transplants and 26 patients received 9/10 mismatched transplants. The median age was 59 years. At a median follow-up of 15 months (range 0.6 to -33 months), the 1-year OS in MUD and MMUD cohort was 75% and 50%, respectively (P = 0.027). The corresponding one-year PFS was 67% and 35%, respectively (P = 0.0024). The incidence of grade 3-4 acute GVHD was 11.8% in MUD and 3.8% in MMUD group, and that of NIH stage moderate/severe chronic GVHD in the 2 groups was 10.5% and 7.6%, respectively. Cytomegalovirus (CMV) reactivation was seen in 49% patients. The cumulative incidence of relapse was 21.1% in the MUD group and 42.3% in the MMUD group.

CONCLUSION

Our experience shows that PTCy and ATG can be combined for GVHD prophylaxis in matched unrelated donor PBSCTs with low rates of Gr3-4 acute GVHD and chronic GVHD, and acceptable relapse rates.