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Anti-PD-1 monotherapy had limited clinical efficacy in relapsed/refractory (r/r) AML patients with higher PD-1 and PD-L1 expression. Hence, we investigated the efficacy and safety of PD-1 inhibitor with DNA hypomethylating agent (HMA) + CAG regimen in patients who had failed prior AML therapy. In this phase 2, single-arm study, r/r AML patients received azacitidine or decitabine plus CAG regimen with tislelizumab. Primary endpoints were efficacy (objective response rate [ORR]) and safety. Secondary endpoints included overall survival (OS), event-free survival (EFS) and duration of response (DOR). Statistical analyses were performed using Stata 14.0 and SPSS 20.0 software where P < 0.05 denoted significance. Twenty-seven patients were enrolled patients and completed 1 cycle, and 14 (51.9%) and 4 (14.8%) patients completed 2 and 3 cycles, respectively. ORR was 63% (14: complete remission [CR]/CR with incomplete hematologic recovery [CRi], 3: partial remission (PR), 10: no response [NR]). Median OS (mOS) and EFS were 9.7 and 9.2 months, respectively. With a median follow-up of 8.2 months (1.1-26.9), the mOS was not reached in responders (CR/CRi/PR) while it was 2.4 months (0.0-5.4) in nonresponders (P = 0.002). Grade 2-3 immune-related adverse events (irAEs) were observed in 4 (14.8%) patients and 3 nonresponders died of lung infection after treatment. Tislelizumab + HMA + CAG regimen showed improved outcomes in r/r AML patients with lower pretherapy leukemia burden. irAEs were mild and low-grade and higher pretherapy bone marrow CD4 + CD127 + PD-1 + T cells might serve as a predictor of treatment response.ClinicalTrials.gov identifier NCT04541277., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

In allogeneic hematopoietic stem cell transplantation recipients, cytomegalovirus (CMV) infection can cause overt CMV-associated disease, which is a main cause of transplantation-associated mortality. CMV infection correlates closely with donor's type. We therefore examined whether risk factors of CMV reactivation and clinical endpoints in patients with hematologic malignancies after allogeneic peripheral blood stem cell transplantation (PBSCT) differed between using matched-sibling donors (MSD-SCT) and haploidentical donors (HID-SCT). In this retrospective cohort study, we enrolled in 200 consecutive patients received an unmanipulated G-CSF-mobilized allogeneic PBSCT. Ninety (45%) patients received MSD-SCT and 110 (55%) received HID-SCT. Quantitative PCR was used for monitoring of CMV reactivation after transplantation. One-year cumulative incidence of CMV DNAemia was 55.0%, ranging from 23.5% in MSD-SCT group to 81.0% in HID-SCT group (p < 0.001). Although univariate analyses showed that non-myeloid malignancies, disease in complete remission status at transplantation, pretreatment with antithymocyte globulin, HLA-haploidentical donors, male donors, previous Epstein-Barr virus DNAemia, and absolute lymphocyte count on day 30 < 0.6 × 10 9 /L were respectively associated with CMV reactivation after transplantation in total cohort of recipients (all p < 0.05), haploidentical donors were found to be the only independent predictor in multivariate analyses (Hazard ratio = 6.4, p < 0.001). Furthermore, univariate analyses revealed that non-myeloid malignancies and previous Epstein-Barr virus DNAemia were respectively associated with CMV reactivation in MSD-SCT recipients, and female was associated with CMV reactivation in HID-SCT recipients (all p < 0.05). In HID-SCT recipients, but not MSD-SCT recipients, previous CMV DNAemia was associated with a lower cumulative incidence of acute graft-versus-host disease (49.2% vs. 72.6%, p < 0.001). CMV DNAemia did not play a role in the relapse rate, but it was strongly associated with an increased risk of non-relapse mortality either in total cohort of recipients (30.5% vs. 13.7%; p = 0.003) or in the HID-SCT subgroup (36.0% vs. 16.7%; p = 0.030). Relapse-free survival and overall survival in total cohort of recipients with CMV DNAemia were both inferior to those without CMV DNAemia (45.3% vs. 57.6% and 54.8% vs. 65.8%, respectively; both p < 0.05). However, in subgroup analysis according to donor's type, neither relapse-free survival nor overall survival was impacted by CMV status (both p > 0.05). This study addressed differences in incidence, risk factors, and associations with clinical outcomes of CMV reactivation after haploidentical versus matched-sibling PBSCT.

In allogeneic hematopoietic stem cell transplantation recipients, reactivation of Epstein-Barr virus (EBV) can cause post-transplantation lymphoproliferative disorder (PTLD), which may rapidly progress to multiorgan failure and even death. Development of EBV PTLD correlates very closely with use of anti-thymocyte globulin (ATG) and type of transplant. To assess the incidences and clinical features of EBV DNAemia and PTLD in the setting of stem cell transplantation using unmanipulated G-CSF-primed allogeneic peripheral blood stem cells as graft, we performed a retrospective analysis of stem cell transplantation from HLA-matched sibling donors (MSD-SCT, n = 90) or HLA-haploidentical related donors (HID-SCT, n = 110) in patients with hematological malignancies. All of HID-SCT recipients and 27.8% of MSD-SCT recipients received an ATG-containing conditioning regimen. One-year cumulative incidence of EBV DNAemia was 44.1%, ranging from 4.8% in MSD-SCT recipients not using ATG to 20.0% in MSD-SCT recipients using ATG, and 73.7% in HID-SCT recipients. Risk factors for EBV reactivation included use of ATG (p = 0.008), male donor (p = 0.034), and cytomegalovirus DNAemia (p < 0.001). One-year incidence of EBV PTLD was 11.9%, ranging from 1.8% in recipients of MSD-SCT not using ATG to 4.4% in recipients of MSD-SCT using ATG, and 23.5% in recipients of HID-SCT. Risk factors for PTLD after HID-SCT included in fludarabine-containing conditioning regimen (p = 0.010), cytomegalovirus DNAemia (p = 0.036), and patient's age < 40-yr (p = 0.032). Two-year non-relapse mortality was higher for patients with EBV DNAemia than those without EBV DNAemia (35.8% vs. 15.3%, p = 0.002). One-year relapse-free survival and overall survival among patients with PTLD were 40.2% and 44.9%, respectively, as opposed to 63.4% and 68.4% among patients without PTLD (both p < 0.05). In multivariate analyses, EBV DNAemia predicted a lower risk of relapse (p = 0.025), while PTLD was a marginally significant predictor of relapse (p = 0.092). This study identified patients at risk of EBV reactivation and PTLD after unmanipulated allogeneic peripheral blood stem cell transplantation.

Donor lymphocyte infusion (DLI) might be used prophylactically to reduce relapse after allogeneic hematopoietic stem cell transplantation for very high-risk leukemia/lymphoma without effective targeted therapy. To compare the safety and efficacy of prophylactic DLI for prevention of relapse after allogeneic peripheral blood stem cell transplantation from haploidentical donors (HID-SCT) and matched-sibling donors (MSD-SCT) in patients with very high-risk acute myeloid leukemia (AML), we performed a retrospective analysis in a cohort of 21 HID-SCT and 13 MSD-SCT recipients, displaying similar baseline characteristics except for donor's gender distribution. Grade 2-4 acute graft-versus-host disease (GVHD) at 100-day post-DLI was higher in HID-SCT group than that in MSD-SCT group (59.5% vs. 30.8%, p = 0.05). The grade 3-4 acute GVHD (17.5% vs. 7.7%), 1-year chronic GVHD (36.6% vs. 33.2%), and severe chronic GVHD (15.3% vs. 27.3%) were not statistically significant different between groups. One-year non-relapse mortality was higher in HID-SCT group than that in MSD-SCT group with marginal significance (27.9% vs. 0.0%, p = 0.061). One-year relapse rate was not statistically significant different between HID-SCT group and MSD-SCT group (21.6% vs. 36.5%, p = 0.543). For HID-SCT recipients, 1-year relapse rate was lower in patients receiving prophylactic DLI than that in a control cohort of eight patients with same very high-risk features but not receiving prophylactic DLI (62.5% vs. 28.3%, p = 0.037). No statistically significant difference was observed in 1-year overall survival (OS, 55.1% vs. 83.9%, p = 0.325) and relapse-free survival (RFS, 50.1% vs. 74.0%, p = 0.419) rates between HID-SCT group and MSD-SCT group. In multivariate analyses, non-remission status prior to transplant, poor-risk gene mutations, and donor's age ≥ 48 years predicted a higher risk of relapse after DLI. Non-remission status prior to transplant predicted inferior OS and RFS. Patient's age ≥ 40 years also predicted an inferior OS. In conclusion, prophylactic DLI was very safe and efficient for reducing relapse in patients with very high-risk AML receiving MSD-SCT. In the recipients of HID-SCT, the application of prophylactic DLI could reduce the risk of relapse, although with a higher incidence of DLI-associated acute GVHD than those of MSD-SCT.

Unmanipulated haploidentical peripheral blood stem cell transplantation (haplo-PBSCT) has been an established treatment to cure high-risk leukemia/lymphoma. Relapse is the main cause of treatment failure for patients with relapsed/refractory disease or with very high-risk gene mutations such as TP53, TET2, and DNMT3a. In this study, we aimed to establish the tolerance and efficacy of prophylactic donor lymphocyte infusion (DLI) with G-CSF-primed peripheral blood progenitors for prevention of relapse in these very high-risk patients after haplo-PBSCT. The prophylactic DLI was given at a median of 77 days after transplantation in 31 of 45 consecutive patients with very high-risk leukemia/lymphoma. The median dose of CD3 + cells for infusion was 1.8 × 10 7 /kg. The 100-day incidences of acute graft-versus-host disease (GVHD) grades 2-4 and 3-4 after DLI were 55.3% and 10.2%. The 2-year incidences of chronic GVHD and severe chronic GVHD were 52.0% and 18.2%. The 2-year incidences of non-relapse mortality and relapse were 33.1% and 32.5%. The 2-year probabilities of overall survival and relapse-free survival were 40.1% and 31.9%. Poor-risk gene mutations (p = 0.029), disease in non-remission status prior to transplantation (p = 0.005), and donors older than 40 years of age (p = 0.043) were associated with relapse after DLI. In multivariate analysis, disease in non-remission status prior to transplantation was an independent risk factor of relapse (hazard ratio = 4.079; p = 0.035). These data showed the feasibility of the prophylactic DLI in the haplo-PBSCT setting and the anti-leukemic efficacy in very high-risk leukemia/lymphoma.