TOPLINE:
Programmed death-1 (PD-1) inhibition with pembrolizumab led to durable remission in 31.3% of patients with early acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) relapse after hematopoietic cell transplantation (HCT). Mixed CD3 chimerism predicted response, but 37.5% developed severe graft-vs-host disease (GVHD).
METHODOLOGY:
A prospective phase 1B clinical trial enrolled 16 patients with AML (n = 12) and MDS (n = 4) who experienced relapse after HCT, with a median time to relapse of 5.5 months and median pretreatment bone marrow blast percentage of 21.5%.
Participants received 200 mg pembrolizumab intravenously every 21 days for up to four cycles (induction), with responding patients eligible for maintenance therapy up to 1 year.
Primary objectives included as