Serious acute or chronic graft-versus-host disease after hematopoietic cell transplantation: a comparison of myeloablative and nonmyeloablative conditioning regimens.

We previously reported a 25% incidence of serious graft-versus-host disease (GVHD) (that is, acute or chronic GVHD that caused death, lengthy hospitalization or disability, or resulted in recurrent major infections) among 171 hematopoietic cell transplantation (HCT) recipients after nonmyeloablative (NMA) regimen. Here we present a retrospective study applying the same criteria to 264 recipients of peripheral blood HCT after myeloablative (MA) regimen, and compare the results with the previous study after additional follow-up. The MA group was younger and had lower comorbidity scores at HCT than those in the NMA group. The overall incidence of serious GVHD was 17% (44/264) in the MA group versus 28% (48/171) in the NMA group. The adjusted hazard ratio (HR) of serious GVHD in the MA group compared to the NMA group was 0.65 (95% CI, 0.4-1.1); P=0.13, and if follow-up was censored at the onset of recurrent or progressive malignancy, HR was 0.67 (95% CI, 0.4-1.3), P=0.22. We conclude that the choice between MA and NMA regimens does not greatly affect the risk of serious GVHD as an overall indicator of outcomes related to either acute or chronic GVHD. Serious GVHD may be considered as an endpoint in clinical trials with GVHD-related outcomes.