Biol Blood Marrow Transplant. 2020 Jul 26:S1083-8791(20)30458-4. doi: 10.1016/j.bbmt.2020.07.025. Online ahead of print.
The use of myeloablative conditioning (MAC) in umbilical cord blood transplantation (UCBT) has been associated with high non-relapse mortality (NRM) in patients >40 years, especially those having a high HLA disparity, thus limiting wider applications. We hypothesized that the NRM advantage of reduced intensity conditioning (RIC) and higher GVL associated with greater HLA disparities would expand its use for patients (40-60 years) without compromising efficacy, and compared outcomes between RIC versus MAC regimens. 288 patients aged 40 to 60 years, with de novo AML, receiving UCBT with at least 2 HLA mismatches with RIC (n=166) or MAC (n=122) regimens were included. As compared to RIC, the MAC cohort included relatively younger patients, having received more single UCBT, with lower total nucleated cell counts, and more in vivo T-cell depletion. Median time to neutrophil engraftment, infections (bacterial, viral and fungal), as well as grade II-IV acute and chronic graft-versus-host disease were similar in both groups. In the multivariate analysis, overall survival (HR-0.98, p=0.9), NRM (HR-0.68, p=0.2) and relapse (HR- 1.24, p=0.5) were not different between RIC and MAC. Refractory disease was associated with worse survival. Outcomes of UBCT for patients 40-60 years having ≥2 HLA mismatches are comparable after RIC or MAC regimen.