神田 善伸

Rapid tapering of cyclosporine (CsA) in the early phase after allogeneic transplantation may induce a potent graft-versus-leukemia/lymphoma (GVL) effect. We retrospectively reviewed the outcomes of patients with high-risk hematological malignancies who underwent their first transplantation at our institution. The blood CsA concentration was maintained at around 300 ng/ml. Our planned schedule for tapering CsA in patients without graft-versus-host disease (GVHD) or with limited GVHD was to reduce the dose by 10% per week starting from day 30 for related HSCT or from day 50 for unrelated HSCT. In total, we began tapering CsA in 36, and classified them into 2 an "On-schedule group" or "Delayed group" based on the timing of starting tapering. The cumulative incidences of grade II-IV acute GVHD overall were 33.8% and 39.4% (P = 0.746) in the On-schedule and Delayed groups. The On-schedule group showed no significant difference in non-relapse mortality, but showed a trend toward a higher relapse rate, resulting in significantly worse overall survival (55.6% vs 72.2% at 1y, P = 0.025) and worse disease-free survival (38.9% vs 66.7% at 1y, P = 0.059). These findings suggest that early CsA tapering after HSCT in high-risk patients was not effective.

We retrospectively evaluated the impacts of using granulocyte colony-stimulating factor (G-CSF) and its timing on posttransplant outcomes for 9766 adults with acute myeloid leukemia (AML) between 2013 and 2022 using a Japanese database. We separately evaluated three distinct cohorts based on graft type: 3248 received bone marrow transplantation (BMT), 3066 received peripheral blood stem cell transplantation (PBSCT), and 3452 received single-unit cord blood transplantation (CBT). Multivariate analysis showed that G-CSF administration significantly accelerated neutrophil recovery after BMT, PBSCT, and CBT. However, it was associated with a higher risk of grades II-IV acute graft-versus-host disease (GVHD) across all graft types. Moreover, an increased incidence of overall chronic GVHD was observed with G-CSF administration in BMT and CBT patients, but not in PBSCT patients. G-CSF administration significantly improved overall survival (OS) and leukemia-free survival (LFS) only following CBT. Regarding the timing of G-CSF, in comparison with late initiation of G-CSF (Days 5-10), early initiation (Days 0-4) did not provide benefits for hematopoietic recovery regardless of graft type. In contrast, late initiation was significantly associated with a lower risk of grades II-IV acute GVHD and better OS and LFS in CBT patients. These data demonstrated that G-CSF administration accelerated neutrophil recovery and increased the risk of grades II-IV acute GVHD across all graft types, but significantly improved survival outcomes but only following CBT. Therefore, routine use of G-CSF should be considered for CBT in adult patients with AML.

HLA-haploidentical haematopoietic cell transplantation with post-transplant cyclophosphamide (PTCy-haplo) is emerging as an effective alternative due to donor availability and safety. We conducted a nationwide retrospective study comparing the outcomes of PTCy-haplo with both anti-thymocyte globulin (ATG)-free and ATG-administered matched unrelated donors (MUD) transplantation, using peripheral blood stem cells as the first transplantation for acute myeloid leukaemia (AML). Our study showed a lower and slower haematopoietic recovery and a higher incidence of infection-related deaths after PTCy-haplo than after MUD transplantation. In addition, we revealed an increased risk of acute and chronic graft-versus-host disease (GVHD) in ATG-free MUD transplantation in comparison to PTCy-haplo. For grades III-IV acute GVHD, the hazard ratio (HR) was 2.71 (95% CI, 1.46-5.01), and for extensive chronic GVHD, the HR was 3.11 (95% CI, 2.07-4.68). There was no significant difference regarding overall survival amongst the groups. In addition, GVHD-free relapse-free survival (GRFS) was lower in ATG-free MUD transplantation than in PTCy-haplo (HR, 1.46; 95% CI, 1.17-1.82). Notably, ATG-administered MUD transplantation showed no significant difference in GRFS from PTCy-haplo, negating the advantage of PTCy. Our results suggest that PTCy-haplo could be viable for AML patients without an HLA-matched related donor.

Allogeneic hematopoietic stem cell transplantation from a female donor to a male recipient (female-to-male allo-HCT) is a well-established risk factor for chronic graft-versus-host disease (GVHD) and non-relapse mortality (NRM). The inferior outcomes of female-to-male allo-HCT are considered to be due to allo-immunity against H-Y antigens. However, the influence of minor histocompatibility antigens in haplo-identical allo-HCT remains to be elucidated. We investigated the impact of female-to-male allo-HCT according to the haplo-HCT subtype. In the post-transplant cyclophosphamide (PTCY) cohort (n = 660), a female-to-male sex-mismatch was significantly associated with a decreased risk of relapse (HR: 0.70 [95% CI: 0.49-0.99], P = 0.045), but not with overall survival (OS) or NRM (HR: OS 0.89 [95% CI: 0.68-1.16], P = 0.40; NRM 0.98 [95% CI: 0.68-1.41], P = 0.90). On the other hand, in the non-PTCY cohort (n = 219), a female-to-male sex-mismatch was associated with inferior risks of OS and NRM, but was not associated with relapse. These results suggested that the survival impact of the haplo-HCT subtype differed according to the presence of a sex-mismatch. PTCY might be feasible for overcoming the inferiority of female-to-male allo-HCT and might preserve a GVL effect against H-Y antigens.

Chronic graft-versus-host disease (GVHD) is 1 of the major complications after allogeneic hematopoietic cell transplantation (allo-HCT). Although various risk factors for chronic GVHD have been reported, limited data are available regarding the impact of acute GVHD on chronic GVHD. We examined the association between acute and chronic GVHD using a Japanese registry data set. The landmark point was set at day 100 after allo-HCT, and patients who died or relapsed before the landmark point were excluded. In total, 14 618 and 6135 patients who underwent allo-HCT with bone marrow or peripheral blood (BM/PB) and with umbilical cord blood (UCB), respectively, were analyzed. In the BM/PB cohort, the risk for chronic GVHD that requires systemic steroids increased with each increase in acute GVHD grade from 0 to 2 (grade 0 vs 1 [hazard ratio (HR), 1.32; 95% confidence interval (CI), 1.19-1.46; P < .001]; grade 1 vs 2 [HR, 1.41; 95% CI, 1.28-1.56; P < .001]), but the risk was similar between acute GVHD grade 2 and grade 3 to 4 (HR, 1.02; 95% CI, 0.91-1.15; P = 1.0). These findings were confirmed in the UCB cohort. We further observed that the risk for severe chronic GVHD increased with each increment in the grade of acute GVHD, even between acute GVHD grade 2 and grade 3 to (grade 2 vs 3-4: HR, 1.70; 95% CI, 1.12-2.58; P = .025). In conclusion, the preceding profiles of acute GVHD should help to stratify the risk for chronic GVHD and its severity, which might be useful for the development of risk-adopted preemptive strategies for chronic GVHD.