Transplant outcomes for patients with therapy-related acute myeloid leukemia with prior lymphoid malignancy: an ALWP of EBMT study

Allogeneic haematopoietic cell transplantation for therapy-related myeloid neoplasms arising following treatment for lymphoma: a retrospective study on behalf of the Chronic Malignancies Working Party of the EBMT

Therapy-related myeloid neoplasms (t-MN), either myelodysplastic neoplasms (t-MDS) or acute myeloid leukemias (t-AML), have a poor prognosis and allogeneic haematopoietic cell transplantation (allo-HCT) represents the only curative option. In this multicenter, registry-based study, we analyzed outcomes of 378 patients undergoing first allo-HCT between 2006-2017 for t-MN arising secondary to lymphoma treatment. Median age was 58 years at allo-HCT; 222 (59%) had a diagnosis of t-MDS and 156 (41%) of t-AML, respectively. At the time of allo-HCT, 46% of t-MN cases were reported as in complete remission (CR) and 15% of lymphomas were recorded as not in remission. A reduced intensity conditioning regimen was used in 70% of cases. For the entire cohort, 5-year OS, and t-MN PFS, relapse incidence and NRM were 32%, 28%, 35% and 37%, respectively. In multivariable analysis, undergoing allo-HCT with t-MN not in CR and older age were associated with significantly worse OS, PFS and NRM. At 5 years post allo-HCT, the relapse incidence of lymphoma was low at 3%, while the rate of secondary malignancies was 8%. This analysis shows the curative potential of allo-HCT for patients with t-MN arising secondary to lymphoma treatment in approximately a third of patients.

Allogeneic hematopoietic stem cell transplantation for adults with therapy-related acute myeloid leukaemia: a retrospective multicentre study on behalf of the SFGM-TC

We report the results from a multicentre retrospective study of 220 adult patients who underwent allogeneic hematopoietic stem cell transplantation (alloHSCT) for therapy-related acute myeloid leukaemia (t-AML). Median age at t-AML diagnosis was 56 years, with a prior history of haematological (45%) or breast (34%). Median time from cytotoxic exposure to t-AML diagnosis was 54.7 months. At transplant, around 20% of patients had measurable residual disease and 3% of patients were not in complete remission. The median follow-up was 21.4 months (Q1-Q3, 5.9-52.8). At 12 months, overall survival (OS), event-free survival (EFS), and graft-versus-host-disease (GVHD)-free-relapse-free survival (GRFS) were 60.7% (95% CI 54.6-67.5), 52.8% (95% CI 46.5-68.4), and 44.1% (95% CI 37.6-51.8), respectively. At 5 years, OS, EFS, and GRFS were 44.1% (95% CI 37.4-52.1), 40.4% (95% CI 33.9-48.1), and 35.3% (95% CI 28.8-43.3), respectively. At last follow-up, 44% of patients were in complete remission (n = 96) and transplant-related mortality accounted for 21% of all deaths (n = 119). Multivariable analysis revealed that uncontrolled t-AML at transplant was associated with lower EFS (HR 1.94, 95% CI 1.0-3.7, p = 0.041). In conclusion, alloHSCT for t-AML shows encouraging results and offers additional opportunity with the emergence of novel pre-graft therapies.

Poor outcome of allogeneic transplantation for therapy-related acute myeloid leukemia induced by prior chemoradiotherapy

Therapy-related acute myeloid leukemia (t-AML) is a therapeutic challenge as a late complication of chemotherapy (CHT) and/or radiotherapy (RT) for primary malignancy. Allogeneic hematopoietic stem cell transplantation (allo-HSCT) presents itself as a curative approach. To establish the optimal allo-HSCT strategy for t-AML, we evaluated the relationship between characteristics of primary malignancy and allo-HSCT outcomes. Patients with t-AML or de novo acute myeloid leukemia (AML) who underwent first allo-HSCT in Japan from 2011 to 2018 were identified using a nationwide database. The detailed background of t-AML was obtained by additional questionnaires. Multivariate analysis and propensity score matching (PSM) analysis were performed to detect the prognostic factors associated with t-AML and compare outcomes with de novo AML. We analyzed 285 t-AML and 6761 de novo AML patients. In patients with t-AML, receiving both CHT and RT for primary malignancy was an independent poor-risk factor for relapse and overall survival (OS) (hazard ratio (HR) 1.62; p = 0.029 and HR 1.65; p = 0.009, reference: CHT alone group), whereas other primary malignancy-related factors had no effect on the outcome. Compared to the CHT alone group, complex karyotypes were significantly increased in the CHT + RT group (86.1% vs. 57.5%, p = 0.007). In the PSM cohort, t-AML patients with prior CHT and RT had significantly worse 3-year OS than those with de novo AML (25.2% and 42.7%; p = 0.009). Our results suggest that prior CHT and RT for primary malignancy may be associated with increased relapse and worse OS of allo-HSCT in t-AML.

Allogeneic hematopoietic cell transplantation in patients with therapy-related myeloid neoplasm after breast cancer: a study of the Chronic Malignancies Working Party of the EBMT

We performed a registry study on therapy-related myeloid neoplasm (t-MN), both therapy-related myelodysplastic syndrome (t-MDS) and acute myeloid leukemia (t-AML) following treatment for breast cancer who underwent a first allogeneic hematopoietic cell transplant (allo-HCT). Of 252 identified female patients (median age 57 years), 77% were transplanted for t-AML and 23% for t-MDS, with a median time from breast cancer diagnosis to the diagnosis of tMN and subsequent allo-HCT of 3.7 and 4.6 years, respectively. At transplant, 191 patients were in remission for breast cancer, while 4 were not (57 missing). T-MN was in a complete remission at the time of transplant in 67% of patients. 2-year overall survival, relapse free-survival, relapse incidence and non-relapse mortality were 50%, 45%, 33%, and 22%, respectively. Multivariable analysis revealed that if the t-MN was not in CR pre-transplant, this was associated with lower OS, RFS, and a higher relapse incidence. Seventeen cases of breast cancer recurrence were recorded after a median of 2.4 years post-transplant, and relapse of primary breast cancer accounted for 7% of deaths. This study indicates that allo-HCT for t-MN following treatment for breast cancer shows encouraging transplant outcomes. The incidence of breast cancer relapse post-transplant remains a cause for concern.

Characterization of myeloid neoplasms following allogeneic hematopoietic cell transplantation

We compared characteristics of myeloid neoplasms (MNs) following allogeneic hematopoietic cell transplantation (HCT) versus autologous HCT using a Japanese HCT registry database. Among 43 788 patients who underwent allogeneic (n = 18 874) or autologous HCT (n = 24 914) for non-myeloid malignancies or non-malignant diseases, 352 developed MNs. The cumulative incidence of MNs was lower after allogeneic HCT than after autologous HCT (0.3% vs. 1.8% at 10 years, respectively, p < .001). Compared with autologous HCT, MNs following allogeneic HCT developed in younger patients (median, 42 vs. 57 years old, respectively) and sooner after HCT (median, 16 vs. 33 months, respectively). Approximately half of MNs following allogeneic HCT were donor-derived and occurred later than recipient-derived MNs (median, 26 vs. 6 months, respectively, p = .003). In multivariate analysis, reduced-intensity conditioning and cord blood transplantation were associated with MN development after allogeneic HCT. Overall survival was similar in patients who developed MNs following allogeneic versus autologous HCT (18% vs. 22% at 5 years, respectively, p = .48). Patient age ≥ 55 years, the presence of previous HCT, AML subtype, and chromosome 5 or 7 abnormalities were adverse factors for overall survival after MN diagnosis. Further research is warranted to elucidate the mechanisms of MN development following allogeneic HCT.

Outcomes of pediatric patients with therapy-related myeloid neoplasms

Long-term outcomes after allogeneic hematopoietic cell transplantation (HCT) for therapy-related myeloid neoplasms (tMNs) are dismal. There are few multicenter studies defining prognostic factors in pediatric patients with tMNs. We have accumulated the largest cohort of pediatric patients who have undergone HCT for a tMN to perform a multivariate analysis defining factors predictive of long-term survival. Sixty-eight percent of the 401 patients underwent HCT using a myeloablative conditioning (MAC) regimen, but there were no statistically significant differences in the overall survival (OS), event-free survival (EFS), or cumulative incidence of relapse and non-relapse mortality based on the conditioning intensity. Among the recipients of MAC regimens, 38.4% of deaths were from treatment-related causes, especially acute graft versus host disease (GVHD) and end-organ failure, as compared to only 20.9% of deaths in the reduced-intensity conditioning (RIC) cohort. Exposure to total body irradiation (TBI) during conditioning and experiencing grade III/IV acute GVHD was associated with worse OS. In addition, a diagnosis of therapy-related myelodysplastic syndrome and having a structurally complex karyotype at tMN diagnosis were associated with worse EFS. Reduced-toxicity (but not reduced-intensity) regimens might help to decrease relapse while limiting mortality associated with TBI-based HCT conditioning in pediatric patients with tMNs.

Allogeneic hematopoietic stem cell transplantation for therapy-related myeloid neoplasms following treatment of a lymphoid malignancy

Advances in lymphoma treatment lead to increasing numbers of long-term survivors. Thus, secondary therapy-related myeloid neoplasms (t-MN) gain clinical relevance. We analyzed 38 t-MN patients receiving an allogeneic stem cell transplantation (SCT) after successful cytotoxic treatment of Hodgkin lymphoma (n = 9), non-Hodgkin lymphoma (n = 24), and multiple myeloma (n = 5), who had developed t-AML (n = 20) or t-MDS (n = 18). Overall survival (OS) and relapse-free survival at 3 years after allogeneic SCT were 43% and 39%. The cumulative incidences of relapse and non-relapse mortality (NRM) at 3 years were 19% and 42%. More than one therapy line for the lymphoid malignancy resulted in a significantly higher NRM rate and inferior 3-year-OS. Our data indicate that allogeneic SCT for patients with t-MN after treatment of a lymphoid malignancy leads to OS rates comparable to patients transplanted for de novo MN. Multiple lines of lymphoma therapy increase NRM and lead to inferior survival after allogeneic SCT.

Bendamustine with total body irradiation conditioning yields tolerant T-cells while preserving T-cell-dependent graft-versus-leukemia

Graft-versus-host disease (GvHD) remains a significant impediment to allogeneic hematopoietic cell transplantation (HCT) success, necessitating studies focused on alleviating GvHD, while preserving the graft-versus-leukemia (GvL) effect. Based on our previous studies showing bendamustine with total body irradiation (BEN-TBI) conditioning reduces GvHD compared to the current clinical standard of care cyclophosphamide (CY)-TBI in a murine MHC-mismatched bone marrow transplantation (BMT) model, this study aimed to evaluate the role and fate of donor T-cells following BEN-TBI conditioning. We demonstrate that BEN-TBI reduces GvHD compared to CY-TBI independently of T regulatory cells (Tregs). BEN-TBI conditioned mice have a smaller proportion and less activated donor T-cells, with lower CD47 expression, early post-transplant, but no sustained phenotypic differences in T-cells. In BEN-TBI conditioned mice, donor T-cells gain tolerance specific to host MHC antigens. Though these T-cells are tolerant to host antigens, we demonstrate that BEN-TBI preserves a T-cell-dependent GvL effect. These findings indicate that BEN-TBI conditioning reduces GvHD without compromising GvL, warranting its further investigation as a potentially safer and more efficacious clinical alternative to CY-TBI.