Outcome of T-cell-replete haploidentical stem cell transplantation improves with time in adults with acute lymphoblastic leukemia: A study from the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation.

BACKGROUND: The use of haploidentical hematopoietic cell transplantation (haplo-HCT) with posttransplantation cyclophosphamide prophylaxis is gaining traction in patients with acute lymphoblastic leukemia (ALL). METHODS: The Acute Leukemia Working Party/European Society for Blood and Marrow Transplantation registry was used to evaluate the outcomes of adult patients with ALL who underwent haplo-HCT during 2011 through 2015 and compared them with the outcomes of those who underwent transplantation during 2016 through 2018. RESULTS: The analysis consisted of 195 patients, including 79 who underwent transplantation during 2011 through 2015 and 116 who underwent transplantation during 2016 through 2018. Overall, the 2-year leukemia-free survival and relapse incidence rates were 56.5% and 21%, respectively. The 100-day incidence of grade 2 through 4 acute graft-vs-host disease (GVHD) was 34.5%. The rates of nonrelapse mortality (NRM) and overall survival (OS) were 22.5% and 64.7%, respectively. Patients who underwent transplantation during 2016 through 2018 experienced improved rates of leukemia-free survival (64.9% vs 47.3%; P = .019) and OS (75.5% vs 53.5%; P = .006). Patients who underwent transplantation during 2016 through 2018 developed more grade 2 through 4 acute GVHD (42% vs 26.4%; P = .047). The incidence of relapse, GVHD-free/relapse-free survival, grade 3 and 4 acute GVHD, chronic GVHD, and extensive chronic GVHD did not differ significantly between groups. In multivariate analysis, more recently transplanted patients had a significantly reduced risk of NRM (hazard ratio, 0.44; 95% CI, 0.22-0.89; P = .022) and improved OS (hazard ratio, 0.47; 95% CI, 0.26-0.86; P = .014). A comparable analysis of patients who had acute myeloid leukemia during the same timeframes did not reveal any statistically significant differences in any outcomes. CONCLUSIONS: The outcome of adult patients with ALL who receive posttransplant cyclophosphamide has improved over time, with an impressive 2-year OS of 75% and, most recently, an NRM rate of only 17%.

Redefining and measuring transplant conditioning intensity in current era: a study in acute myeloid leukemia patients.

To address limitations of the currently used reduced-intensity/myeloablative conditioning (RIC/MAC) classification scheme we aimed to develop a tool that can capture more standardized the conditioning intensity of allogeneic hematopoietic cell transplantation (HCT). We assigned intensity weight scores for frequently used conditioning regimen components and used their sum to generate the transplant conditioning intensity (TCI) score. We retrospectively tested the impact of TCI on 8255 adult (45-65 years) acute myeloid leukemia patients who underwent HCT in first complete remission. A Cox model for early nonrelapse mortality (NRM) yielded a 3-group TCI risk scheme (low, intermediate, high) with respective TCI scores of [1-2], [2.5-3.5] and [4-6]. On multivariate modeling, TCI grouping was highly and better predictive for early (day 100 and 180) NRM, 2-year NRM and relapse (REL) as compared with the RIC/MAC classification. Validation was done on 200 bootstrap samples. Moreover, TCI scoring enabled the identification of a distinct subgroup of RIC and MAC conditioning regimens with an intermediate TCI [2.5-3.5] score that had identical outcomes and which are frequently referred as "reduced toxicity conditioning". TCI scheme provides an improvement of the RIC/MAC classification. We propose TCI as a new tool to define and measure the conditioning regimen intensity.

Correction: Redefining and measuring transplant conditioning intensity in current era: a study in acute myeloid leukemia patients.

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