Janny M, Yao, Dongyun, Yang, Mary C, Clark, Salman, Otoukesh, Thai, Cao, Haris, Ali, Shukaib, Arslan, Ibrahim, Aldoss, Andrew, Artz, Idoroenyi, Amanam, Amandeep, Salhotra, Vinod, Pullarkat, Karamjeet, Sandhu, Anthony, Stein, Guido, Marcucci, Stephen J, Forman, Ryotaro, Nakamura, and Monzr M, Al Malki
Post-transplant cyclophosphamide (PTCy) combined with tacrolimus (TAC) as graft-versus-host disease (GvHD) prophylaxis post-hematopoietic cell transplantation (HCT) is safe and effective. Optimal serum levels of TAC in this combination remain undetermined. We hypothesized that TAC at initial steady state (TISS) of10 ng/mL could promote optimal transplant outcomes and prevent TAC-associated toxicities. We retrospectively analyzed a consecutive case series of 210 patients who received PTCy/TAC-based prophylaxis post-HCT from 1/2013-6/2018. Patients received HCT from haploidentical (n = 172) or mismatched donors (n = 38), and flat dose (FD) or weight-based dose (WBD) TAC. Twenty-four-month overall survival (OS), disease free survival (DFS), and relapse rate (RR) were 61%, 56%, and 22%, respectively, in TISS 10 ng/mL cohort (n = 176), and 50%, 43%, and 35%, respectively, in TISS ≥ 10 ng/mL cohort (n = 34) (OS, P = 0.71; DFS, P = 0.097; RR, P = 0.031). OS, DFS, RR, non-relapse mortality, acute GvHD grade II-IV, grade III-IV or chronic GvHD by TISS were similar in multivariable analysis. TISS ≥ 10 ng/mL conferred increased risk of viral infection (P = 0.003). More patients receiving FD vs. WBD had TISS 10 ng/mL (P = 0.001). Overall, TISS 10 ng/mL early post HCT conferred similar survival outcomes and lowered risk of viral infection and toxicities compared to TISS ≥ 10 ng/mL.