We conducted a prospective, randomized, open-label, multicenter study to compare busulfan plus fludarabine (BuFlu) with busulfan plus cyclophosphamide (BuCy) as the conditioning regimen in allogeneic hematopoietic stem cell transplantation (allo-HSCT) for acute myeloid leukemia (AML) in first complete remission (CR1). Totally 108 AML-CR1 patients undergoing allo-HSCT were randomized into BuCy (busulfan 1.6 mg/kg, q12 hours, -7 ~ -4d; cyclophosphamide 60 mg/kg.d, -3 ~ -2d) or BuFlu (busulfan 1.6 mg/kg, q12 hours, -5 ~ -2d; fludarabine 30 mg/m2.d, -6 ~ -2d) group. Hematopoietic engraftment, regimen-related toxicity (RRT), graft-versus-host disease (GVHD), transplant related mortality (TRM), and overall survival were compared between the two groups. All patients achieved hematopoietic reconstitution except for two patients who died of RRT during conditioning. All patients obtained complete donor chimerism by day +30 post-transplantation. The incidence of total and III-IV RRT were 94.4% and 81.5% (P = 0.038), and 16.7% and 0.0% (P = 0.002), respectively, in BuCy and BuFlu group. With a median follow up of 609 (range, 3-2130) days after transplantation, the 5-year cumulative incidence of TRM were 18.8 ± 6.9% and 9.9 ± 6.3% (P = 0.104); the 5-year cumulative incidence of leukemia relapse were 16.5 ± 5.8% and 16.2 ± 5.3% (P = 0.943); the 5-year disease-free survival and overall survival were 67.4 ± 7.6% and 75.3 ± 7.2% (P = 0.315), and 72.3 ± 7.5% and 81.9 ± 7.0% (P = 0.177), respectively in BuCy and BuFlu group. Compared with BuCy, BuFlu as a myeloablative condition regimen was associated with lower toxicities and comparable anti-leukemic activity in AML-CR1 patients undergoing allo-HSCT.

Background: Intensified conditioning regimens (increasing the intensity of standard myeloablative conditioning) for hematological malignancies in allogeneic hematopoietic stem cell transplantation (allo-HSCT) could reduce the relapse rate of the underlying disease, but it might simultaneously increase the transplant-related mortality including the mortality of infections. To explore whether intensified conditioning affected Epstein-Barr virus (EBV) and cytomegalovirus (CMV) infections, 185 patients undergoing allo-HSCT were enrolled. Methods: A total of 104 cases received standard and 81 intensified conditioning. Cyclosporine A (CsA) withdrawal and/or donor lymphocyte infusion (DLI) were conducted in high-risk patients. The EBV-DNA and CMV-DNA levels of blood were monitored regularly by quantitative real-time polymerase chain reaction (RQ-PCR) and immune reconstitution of recipients were analyzed by flow cytometry. Results: The 3-year cumulative incidence of EBV viremia, EBV-associated diseases and mortality of EBV-associated diseases were 25.3% ± 4.6%, 10.5% ± 3.4% and 0.0% ± 0.0% in the standard group, compared with 45.6% ± 6.5%, 26.0% ±5.3% and 7.3% ± 3.1% in the intensified group (P = 0.002, P = 0.002, P = 0.008). The 3-year cumulative incidence of CMV viremia and CMV-associated diseases, mortality of CMV-associated diseases and incidence of bacterial and fungal infections were similar between the two groups (P = 0.855, P = 0.581, P = 0.933, P = 0.142, P = 0.182, respectively). Multivariate analysis showed that intensified conditioning was one of the risk factors for EBV viremia and EBV-associated diseases (P = 0.037, P = 0.037), but it had no effects on CMV infections. The percentage of CD4⁺ T cells and CD4⁺/CD8⁺ ratio at 3 months post-transplantation were lower in the intensified group (P = 0.032, P = 0.022). The 3-year OS and DFS in the standard group were 62.2% ± 5.8% and 60.6% ± 5.6%, compared with 51.6% ± 6.2% and 51.1% ± 5.9% in the intensified group (P = 0.029, P = 0.063). Conclusions: Intensified conditioning represents a promising approach for high-risk hematological malignancies, although it affects early immune reconstitution of recipients and increases the incidence and mortality of EBV infections.

Background: Relapsed or refractory acute myeloid leukemia (R/R AML) has a dismal prognosis. The aim of this study was to investigate the activity and tolerability of venetoclax combined with azacitidine plus homoharringtonine (VAH) regimen for R/R AML. Methods: This phase 2 trial was done at ten hospitals in China. Eligible patients were R/R AML (aged 18–65 years) with an Eastern Cooperative Oncology Group performance status of 0–2. Patients received venetoclax (100 mg on day 1, 200 mg on day 2, and 400 mg on days 3–14) and azacitidine (75 mg/m² on days 1–7) and homoharringtonine (1 mg/m² on days 1–7). The primary endpoint was composite complete remission rate [CRc, complete response (CR) plus complete response with incomplete blood count recovery (CRi)] after 2 cycles of treatment. The secondary endpoints include safety and survival. Results: Between May 27, 2020, and June 16, 2021, we enrolled 96 patients with R/R AML, including 37 primary refractory AML and 59 relapsed AML (16 relapsed after chemotherapy and 43 after allo-HSCT). The CRc rate was 70.8% (95% CI 60.8–79.2). In the patients with CRc, measurable residual disease (MRD)-negative was attained in 58.8% of CRc patients. Accordingly, overall response rate (ORR, CRc plus partial remission (PR)) was 78.1% (95% CI 68.6–85.4). At a median follow-up of 14.7 months (95% CI 6.6–22.8) for all patients, median overall survival (OS) was 22.1 months (95% CI 12.7–Not estimated), and event-free survival (EFS) was 14.3 months (95% CI 7.0–Not estimated). The 1-year OS was 61.5% (95% CI 51.0–70.4), and EFS was 51.0% (95% CI 40.7–60.5). The most common grade 3–4 adverse events were febrile neutropenia (37.4%), sepsis (11.4%), and pneumonia (21.9%). Conclusions: VAH is a promising and well-tolerated regimen in R/R AML, with high CRc and encouraging survival. Further randomized studies are needed to be explored. Trial registration clinicaltrials.gov identifier: NCT04424147.

Sphingolipid, ceramide for example, plays an essential role in regulating cancer cell death. Defects in the generation and metabolism of ceramide in cancer cells contribute to tumor cell survival and resistance to chemotherapy. Ceramide Transfer Protein (CERT) determines the ratio of ceramide and sphingomyelin in cells. Targeting CERT sensitizes solid cancer cells to chemotherapy. However, whether targeting CERT to induce ceramide accumulation thereby improving AML therapy efficiency remains elusive. Here, we show that knocking down CERT inhibits the growth and promotes the apoptosis of AML cells carrying FLT3-ITD mutation. Combining CERT inhibitor with FLT3 inhibitor exhibits synergistic effects on FLT3-ITD mutated acute myeloid leukemia (AML) cells. Additionally, co-treatment of HPA-12 and Crenolanib is effective in FLT3-ITD⁺ and FLT3-TKD⁺ AML patients. The synergistic effects are found to be mediated by the endoplasmic reticulum stress-GRP78/ATF6/CHOP axis and mitophagy. Our data provide an effective strategy to enhance the efficacy of FLT3 inhibitors in AML.

Purpose: We investigated whether homoharringtonine (HHT) added to venetoclax plus azacitidine (VA) could improve outcomes and counteract the negative effects of genetic patterns in patients with relapsed/refractory acute myeloid leukemia (RR-AML). Experimental Design: A multicenter retrospective cohort study of the response and genetic patterns of response to the VA plus HHT (VAH) versus the VA regimens as salvage treatment in patients with RR-AML was performed. The endpoints were the rates of composite complete remission, measurable residual disease, event-free survival, overall survival, and relapse between VAH and VA groups. Results: A total of 321 patients (VAH, n = 172; VA, n = 149) were analyzed. Compared with VA, VAH significantly improved the rates of composite complete remission (44.3% vs. 66.3%; P < 0.001), measurable residual disease negativity (34.8% vs. 59.3%; P = 0.002), prolonged overall survival (median: 15.1 months vs. not reached; P < 0.001), and event-free survival (median: 3.8 vs. 13.0 months; P < 0.001). VAH significantly mitigated the negative impact on VA efficacy of mutated FLT3-ITD/TKD, N/KRAS, and t(8;21)/AML1-ETO, as well as the relatively unfavorable effects of the TET2 and DNMT3A mutations. VAH significantly enhanced the response of patients with nonadverse European LeukemiaNet risk, with a trend toward improved response in those with adverse European LeukemiaNet risk, complex karyotype, and DNMT3A+FLT3+NPM1+. The incidence of grade 3 or higher adverse events was comparable between the two groups. Conclusions: Our findings suggest the addition of HHT to VA might enhance response and mitigate the negative impact of certain genetic patterns in RR-AML while being well tolerated.