Background: Despite scientific advances in hematopoietic cell allografting, glucocorticoid-refractory acute (aGVHD) and chronic graft-versus-host disease (cGVHD) represent major sources of transplant-related morbidity and mortality. We aimed to characterize the activity of pentostatin as rescue therapy for refractory GVHD.
Material/Methods: In a retrospective analysis, we examined the activity of pentostatin as rescue therapy of glucocorticoid-refractory acute and chronic GVHD.
Results: In 12 patients with advanced (overall aGVHD grade III/IV in 8/12) refractory aGVHD, overall response (ORR) was achieved in 6/12, and complete remission (CR) of aGVHD in 4/12 allowing additional rescue immunosuppressive agents. Median overall survival (OS) was 1.4 months (95% CI: 0.26–2.4). Causes of death included refractory aGVHD and infection. In 18 patients with refractory cGVHD (12/18 with severe cGVHD), pentostatin induced CR in 1/18, and partial response (PR) in 9/18. Activity was observed in all affected organs. The median decrease in glucocorticoid therapy over 24 months after pentostatin initiation for refractory cGVHD was 38% (range=0–100%). Median OS was 5 months (95% CI: 1.6 – NR).
Conclusions: Allowing for the utilization of additional immune suppressive agents, this series suggests the activity of pentostatin as rescue therapy of refractory GVHD.

Keywords: acute graft-versus-host disease, chronic graft-versus-host disease, pentostatin, Glucocorticoids