Reduced-dose PTCy + ATG for AML

A prospective pilot study evaluated reduced-dose post-transplant cyclophosphamide (PTCy70; 35 mg/kg on Day 3 and Day 4) + low-dose anti-thymocyte globulin (ATG) vs standard-dose PTCy (PTCy100; 50 mg/kg on Day 3 and Day 4) + low-dose ATG, in 173 patients with acute myeloid leukemia (AML) undergoing matched unrelated donor (MUD) allogeneic hematopoietic stem cell transplantation (allo-HSCT). Endpoints included engraftment kinetics, incidence of infectious complications, incidence of acute graft-versus-host disease (aGvHD), non-relapse mortality (NRM), and overall survival (OS). Results were published in the British Journal of Haematology by Desai et al.

Key data: The median times to neutrophil recovery were 17 days and 19 days in the PTCy70 (n = 41) and PTCy100 (n = 132) groups, respectively (p = 0.03). At Day 28, 100% of patients receiving PTCy70 demonstrated neutrophil engraftment vs 92.4% of patients receiving PTCy100 (p = 0.04). PTCy70 was associated with faster platelet engraftment (13 vs 16 days; p < 0.001) and lower risk of bloodstream infections (BSIs) in multivariable analysis (39% vs 66%; p = 0.007). Cumulative incidence of Grade II–IV (p = 0.17) or III–IV aGvHD (p = 0.08) did not significantly differ between cohorts, nor did occurrence of high-grade fluid overload (p = 0.70) or cardiac events (p = 0.06), and nor did NRM at Day 100 (p = 0.67), or OS at 12 months post-transplant (p = 0.87).

Key learning: Reduced-dose PTCy70 + low-dose ATG demonstrates a favorable early transplant outcome in adults with AML undergoing MUD allo-HSCT without compromising aGvHD control or early survival outcomes, supporting evaluation in larger, randomized trials.