Outcome improvement over time in reduced intensity conditioning hematopoietic transplantation: a 20-year experience

The current study includes all consecutive patients ( N = 484) who received a reduced-intensity conditioning regimen (RIC) allogeneic hematopoietic stem cell transplantation in our center from 1999 to 2020. Conditioning regimens were based on fludarabine with melphalan or busulfan, with low-dose thiotepa and pharmacological GVHD prophylaxis consisted of cyclosporine A (CsA)-methotrexate (MTX)/mofetil (MMF) ( n = 271), tacrolimus-sirolimus ( n = 145), and post-transplantation cyclophosphamide (PTCy)-tacrolimus ( n = 68). The median time of overall follow-up in survivors was 8 years (1–22 years) and was at least 3 years in all three GVHD prophylaxis groups. Thirty-three percent had a high or very high disease risk index, 56% ≥ 4 European bone marrow transplantation risk, and 65% ≥ 3 hematopoietic stem cell transplantation comorbidity index score-age score. Neutrophil and platelet engraftment was longer for PTCy-tacro ( p 0.0001). Cumulative incidence of grade III–IV aGVHD was 17% at 200 days, and that of moderate-severe cGvHD was 36% at 8 years. GVHD prophylaxis was the only prognostic factor in the multivariable analyses for the development of aGVHD and moderate-severe cGVHD ( p 0.0001). NRM and relapse incidences were 29% and 30% at 8 years, while OS and PFS rates were 43% and 39% at 8 years. At 3 years, OS was highest in the PTCy-tacro group (68%) than in the tacro-siro (61%) and CsA-MTX/MMF (49%) cohorts ( p