Unmanipulated haplo-identical donor transplantation compared with identical sibling donor had better anti-leukemia effect for refractory/relapsed acute myeloid leukemia not in remission status

Disease Status and Interval between Hematopoietic Cell Transplantations Predict Outcome of Pediatric Patients Who Undergo Subsequent Transplantation for Relapsed Hematologic Malignancy

Patients with hematologic malignancies who relapse after allogeneic hematopoietic cell transplantation (HCT) have a poor prognosis. Although proceeding to subsequent HCT can provide potential for long-term survival, there are limited data to guide which patients are most likely to benefit and which HCT strategies are best in this heavily pretreated population. The goals of this study were to describe the clinical outcomes of subsequent HCT in pediatric patients with relapsed hematologic malignancies in a cohort enriched for haploidentical donors, and to evaluate the associations of patient-, disease-, and treatment-related factors with survival. We retrospectively evaluated patients who underwent a subsequent HCT for management of post-HCT relapse at a single institution between 2000 and 2021. Among 106 patients who underwent a second allogeneic HCT, the 1-year event-free survival (EFS) was 34% and 1-year overall survival (OS) was 46%, with a 5-year EFS of 26% and 5-year OS of 31%. Only disease-related factors were associated with outcome after second HCT-specifically, the interval between HCTs and the presence or absence of active disease at the time of HCT. In this cohort, patient- and treatment-related factors were not associated with differences in EFS or OS. Patients undergoing a third or fourth HCT (n = 13) had comparable survival outcomes to those undergoing a second HCT. Our experience highlights that a subsequent HCT has curative potential for a subset of patients who relapse after HCT, including those who undergo a subsequent HCT from a haploidentical donor. Although relapse and treatment-related toxicities remain major challenges, our study indicates that achieving complete remission prior to subsequent HCTs has the potential to further improve outcomes.

Salvage hematopoietic stem cell transplantation for patients with higher leukemia burden in relapsed or refractory acute myeloid leukemia: a ten-year study

Patients with relapsed and refractory acute myeloid leukemia (R-R AML), especially those in non-remission (NR) have a poor prognosis after allogeneic hematopoietic stem cell transplantation (allo-HSCT). In order to optimize the entire allo-HSCT process for R-R AML patients and identify potential factors affecting clinical outcomes after HSCT, we retrospectively analyzed 44 adult patients with R-R AML who underwent salvage allo-HSCT while in NR or with concomitant extramedullary leukemia at the Institute of Hematology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology from 2013 to 2022. The 1-year and 2-year overall survival (OS) of the 44 patients were 55.3% (95% confidence interval [CI], 41.1%-74.3%) and 44.4% (95%CI, 30.2%-65.4%), respectively. The 1-year and 2-year cumulative incidence of relapse (CIR) were 39.4% (95%CI, 38.0%-40.7%) and 53.0% (95%CI, 51.0%-55.1%), respectively, and the 1-year and 2-year leukemia-free survival (LFS) were 37.8% (95%CI, 24.8%-57.7%) and 20.3% (95%CI, 9.1%-45.3%), respectively. The 100-day, 1-year and 2-year treatment-related mortality (TRM) was 13.8% (95%CI, 13.3%-14.4%), 22.8% (95%CI, 21.9%-23.7%) and 26.7% (95%CI, 25.5%-27.8%), respectively. Multivariate analysis revealed that patients who developed chronic graft-versus-host disease (cGVHD) after transplantation had lower relapse rate. Our analysis also indicated that patients with blast counts in bone marrow (BM) <20% and those with ≥20% had comparable clinical outcomes after allo-HSCT. In conclusion, our study demonstrated that R-R AML patients in NR or with concomitant extramedullary leukemia can benefit from allo-HSCT, regardless of leukemia burden at the time of transplantation. Patients who experience cGVHD after allo-HSCT may have lower relapse rate due to enhanced graft-versus-leukemia (GVL) effects, but cGVHD should be controlled at mild to moderate level to avoid life-threatening complications.

Immunotherapy in hematologic malignancies: achievements, challenges and future prospects

The immune-cell origin of hematologic malignancies provides a unique avenue for the understanding of both the mechanisms of immune responsiveness and immune escape, which has accelerated the progress of immunotherapy. Several categories of immunotherapies have been developed and are being further evaluated in clinical trials for the treatment of blood cancers, including stem cell transplantation, immune checkpoint inhibitors, antigen-targeted antibodies, antibody-drug conjugates, tumor vaccines, and adoptive cell therapies. These immunotherapies have shown the potential to induce long-term remission in refractory or relapsed patients and have led to a paradigm shift in cancer treatment with great clinical success. Different immunotherapeutic approaches have their advantages but also shortcomings that need to be addressed. To provide clinicians with timely information on these revolutionary therapeutic approaches, the comprehensive review provides historical perspectives on the applications and clinical considerations of the immunotherapy. Here, we first outline the recent advances that have been made in the understanding of the various categories of immunotherapies in the treatment of hematologic malignancies. We further discuss the specific mechanisms of action, summarize the clinical trials and outcomes of immunotherapies in hematologic malignancies, as well as the adverse effects and toxicity management and then provide novel insights into challenges and future directions.

Matched related versus unrelated versus haploidentical donors for allogeneic transplantation in AML patients achieving first complete remission after two induction courses: a study from the ALWP/EBMT

We compared transplants (HSCT) from matched related siblings (MSD) with those from matched 10/10 and mismatched 9/10 unrelated (UD) and T-replete haploidentical (Haplo) donors in acute myeloid leukemia (AML) in first complete remission (CR1) achieved after two inductions, a known poor prognostic factor. One thousand two hundred and ninety-five patients were included: MSD (n = 428), UD 10/10 (n = 554), UD 9/10 (n = 135), and Haplo (n = 178). Acute GVHD II-IV was higher in all groups compared to MSD. Extensive chronic (c) GVHD was significantly higher in UD 9/10 (HR = 2.52; 95% CI 1.55-4.11, p = 0.0002) and UD 10/10 (HR = 1.48; 95% CI 1.03-2.13, p = 0.036) and cGVHD all grades were higher in UD 9/10 vs MSD (HR = 1.77; 95% CI 1.26-2.49, p = 0.0009). Non-relapse mortality was higher in all groups compared to MSD. Relapse incidence, leukemia-free, and overall survival did not differ significantly between donor types. Finally, GVHD-free relapse-free survival was lower in HSCT from UD 9/10 (HR = 1.56, 95% CI 1.20-2.03, p = 0.0009) but not in those from UD 10/10 (HR = 1.13, p = 0.22) and Haplo donors (HR = 1.12, p = 0.43) compared to MSD. In conclusion, in AML patients undergoing HSCT in CR1 achieved after two induction courses 10/10 UD and Haplo but not 9/10 UD donors are comparable alternatives to MSD.

Prognostic factors of second hematopoietic allogeneic stem cell transplantation among hematological malignancy patients relapsed after first hematopoietic stem cell transplantation: A single center study

Introduction

We aimed to evaluate prognostic factors of a second allogeneic stem cell transplantation (allo-HSCT2) among hematological malignancy patients who have relapsed after the first allo-HSCT(allo-HSCT1).

Methods

We retrospectively analyzed 199 hematological malignancy patients who received allo-HSCT2 as a salvage treatment post allo-HSCT1 relapse between November 2012 and October 2021.

Results

The median age at allo-HSCT2 was 23 (range: 3-60) years. The median time to relapse after HSCT1 was 9 (range: 1-72) months. Prior to allo-HSCT2, patients had the following hematopoietic cell transplantation-comorbidity indexes (HCT-CI): 127 with a score of 0, 52 with a score of 1, and 20 with a score of 2 or greater. Fifty percent of patients received chimeric antigen receptor (CAR) T-cell therapy following HSCT1 relapse. Disease status was minimal residual disease (MRD)-negative complete remission (CR) among 119 patients, MRD-positive CR among 37 patients and non-remission (NR) for 43 patients prior to allo-HSCT2. Allo-HSCT2 was performed from a new donor in 194 patients (97.4%) and 134 patients (67.3%) received a graft with a new mismatched haplotype. The median follow-up time was 24 months (range: 6-98 months), and the 2-year OS and LFS were 43.8% ± 4.0% and 42.1% ± 4.1%, respectively. The 2-year cumulative incidence of relapse (CIR) and non-relapse mortality (NRM) was 30.0%±4.8% and 38.5%±3.8%, respectively. Cox regression multivariate analysis showed that disease statusof MRD-negative CR, HCT-CI score of 0 prior to allo-HSCT2, and new mismatched haplotype donor were predictive factors of improved OS and LFS compared to patients without these characteristics. Based on these three favorable factors, we developed a predictive scoring system for patients who received allo-HSCT2. Patients with a prognostic score of 3 who had the three factors showed a superior 2-year OS of 63.3% ± 6.7% and LFS of 63.3% ± 6.7% and a lower CIR of 5.5% ± 3.1% than patients with a prognostic score of 0. Allo-HSCT2 is feasible and patients with good prognostic features prior to allo-HSCT2 -disease status of CR/MRD- and HCT-CI score of 0 as well as a second donor with a new mismatched haplotype could have the maximal benefit from the second allo-HSCT.

Conclusions

Allo-HSCT2 is feasible and patients with good prognostic features prior to allo-HSCT2 -disease status of CR/MRD- and HCT-CI score of 0 as well as a second donor with a new mismatched haplotype could have the maximal benefit from the second allo-HSCT.

Allogeneic hematopoietic stem cell transplantation with myeloablative conditioning regimen for blastic plasmacytoid dendritic cell neoplasm patients in complete remission: a single center study

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare hematopoietic malignancy characterized by poor prognosis even following an allogeneic hematopoietic stem cell transplantation (allo-HSCT). We retrospectively analyzed 15 patients diagnosed with BPDCN who underwent an allo-HSCT with myeloablative conditioning (MAC) at our center. The male to female ratio was 11:4. The median age of 36 (range: 6-70) years, all patients initially presented with extramedullary lesions (13 with cutaneous lesions, 1 in the breast and 1 in the lymph nodes) and involved the bone marrow, two cases were diagnosed as central nervous system leukemia (CNSL). Nine patients were in CR1 and six patients were in CR2 status prior to HSCT. All patients received the MAC regimen and an unmanipulated graft. All patients successfully engraftment and achieved full donor chimerism. One patient developed poor graft function, three patients developed aGVHD (Grade I, II, and IV), and seven patients developed cGVHD (mild in 6; moderate in 1). The median follow-up time for survival was 34 (range: 6-64) months. The primary endpoint, overall leukemia-free survival (LFS) rate and overall survival rate was 73.3 ± 10.5%. Allo-HSCT with MAC is a valid option for BPDCN patients in complete remission.

Sub-myeloablative Second Transplantations with Haploidentical Donors and Post-Transplant Cyclophosphamide have limited Anti-Leukemic Effects in Pediatric Patients

Pediatric patients with high-risk hematologic malignancies who experience relapse after a prior allogeneic hematopoietic cell transplant (HCT) have an exceedingly poor prognosis. A second allogeneic HCT offers the potential for long-term cure but carries high risks of both subsequent relapse and HCT-related morbidity and mortality. Using haploidentical donors for HCT (haploHCT) can expand the donor pool and potentially enhance the graft-versus-leukemia effect but is accompanied by a risk of graft-versus-host disease (GVHD). The goal of this protocol was to intensify the antileukemia effect of haploHCT for pediatric patients with hematologic malignancies that relapsed after prior allogeneic HCT, while limiting regimen-associated toxicities. This phase II clinical trial evaluated a sub-myeloablative preparative regimen consisting of anti-thymocyte globulin, clofarabine, cytarabine, busulfan, and cyclophosphamide, in combination with plerixafor to sensitize leukemic blasts. Participants received a mobilized peripheral blood unmanipulated haploidentical donor graft with one dose of post-transplant cyclophosphamide as GVHD prophylaxis, followed by natural killer (NK) cell addback. Here we report the clinical outcomes and immune reconstitution of 17 participants treated on the study and 5 additional patients treated on similar single-patient treatment plans. Of the 22 participants analyzed, 12 (55%) had active disease at the time of HCT. The regimen provided robust immune reconstitution, with 21 participants (95%) experiencing neutrophil engraftment at a median of 14 days after HCT. In this high-risk population, the overall survival was 45% (95% confidence interval [CI], 24%-64%), with a 12-month event-free survival of 31% (95% CI, 14%-51%) and cumulative incidence of relapse at 12 months of 50% (95% CI, 27%-69%). Four participants (18%) remain in remission at >5 years follow-up. Expected HCT-related organ-specific toxicities were observed, and 13 participants (59%) experienced acute or chronic GVHD. This intensified but sub-myeloablative regimen, followed by a high-dose unmanipulated haploidentical graft, post-transplantation cyclophosphamide, and NK cell infusion, resulted in adequate immune reconstitution but failed to overcome the elevated risks of relapse and treatment-related morbidity in this high-risk population.

[A retrospective comparative study of haplotype hematopoietic stem cell transplantation and human leukocyte antigen-matched sibling donor hematopoietic stem cell transplantation in the treatment of acute B-lymphocyte leukemia]

Objective: To investigate whether haplotype hematopoietic stem cell transplantation (haplo-HSCT) is effective in the treatment of pre transplant minimal residual disease (Pre-MRD) positive acute B lymphoblastic leukemia (B-ALL) compared with HLA- matched sibling donor transplantation (MSDT) . Methods: A total of 998 patients with B-ALL in complete remission pre-HSCT who either received haplo-HSCT (n=788) or underwent MSDT (n=210) were retrospectively analyzed. The pre-transplantation leukemia burden was evaluated according to Pre-MRD determinedusing multiparameter flow cytometry (MFC) . Results: Of these patients, 997 (99.9% ) achieved sustained, full donor chimerism. The 100-day cumulative incidences of neutrophil engraftment, platelet engraftment, and grades Ⅱ-Ⅳ acute graft-versus-host disease (GVHD) were 99.9% (997/998) , 95.3% (951/998) , and 26.6% (95% CI 23.8% -29.4% ) , respectively. The 3-year cumulative incidence of total chronic GVHD was 49.1% (95% CI 45.7% -52.4% ) . The 3-year cumulative incidence of relapse (CIR) and non-relapse mortality (NRM) of the 998 cases were 17.3% (95% CI 15.0% -19.7% ) and 13.8% (95% CI 11.6% -16.0% ) , respectively. The 3-year probabilities of leukemia-free survival (LFS) and overall survival (OS) were 69.1% (95% CI 66.1% -72.1% ) and 73.0% (95% CI 70.2% -75.8% ) , respectively. In the total patient group, cases with positive Pre-MRD (n=282) experienced significantly higher CIR than that of subjects with negative Pre-MRD [n=716, 31.6% (95% CI 25.8% -37.5% ) vs 14.3% (95% CI 11.4% -17.2% ) , P<0.001]. For patients in the positive Pre-MRD subgroup, cases treated with haplo-HSCT (n=219) had a lower 3-year CIR than that of cases who underwent MSDT [n=63, 27.2% (95% CI 21.0% -33.4% ) vs 47.0% (95% CI 33.8% -60.2% ) , P=0.002]. The total 998 cases were classified as five subgroups, including cases with negative Pre-MRD group (n=716) , cases with Pre-MRD<0.01% group (n=46) , cases with Pre-MRD 0.01% -<0.1% group (n=117) , cases with Pre-MRD 0.1% -<1% group (n=87) , and cases with Pre-MRD≥1% group (n=32) . For subjects in the Pre-MRD<0.01% group, haplo-HSCT (n=40) had a lower CIR than that of MSDT [n=6, 10.0% (95% CI 0.4% -19.6% ) vs 32.3% (95% CI 0% -69.9% ) , P=0.017]. For patients in the Pre-MRD 0.01% -<0.1% group, haplo-HSCT (n=81) also had a lower 3-year CIR than that of MSDT [n=36, 20.4% (95% CI 10.4% -30.4% ) vs 47.0% (95% CI 29.2% -64.8% ) , P=0.004]. In the other three subgroups, the 3-year CIR was comparable between patients who underwent haplo-HSCT and those received MSDT. A subgroup analysis of patients with Pre-MRD<0.1% (n=163) was performed, the results showed that cases received haplo-HSCT (n=121) experienced lower 3-year CIR [16.0% (95% CI 9.4% -22.7% ) vs 40.5% (95% CI 25.2% -55.8% ) , P<0.001], better 3-year LFS [78.2% (95% CI 70.6% -85.8% ) vs 47.6% (95% CI 32.2% -63.0% ) , P<0.001] and OS [80.5% (95% CI 73.1% -87.9% ) vs 54.6% (95% CI 39.2% -70.0% ) , P<0.001] than those of MSDT (n=42) , but comparable in 3-year NRM [5.8% (95% CI 1.6% -10.0% ) vs 11.9% (95% CI 2.0% -21.8% ) , P=0.188]. Multivariate analysis showed that haplo-HSCT was associated with lower CIR (HR=0.248, 95% CI 0.131-0.472, P<0.001) , and superior LFS (HR=0.275, 95% CI 0.157-0.483, P<0.001) and OS (HR=0.286, 95% CI 0.159-0.513, P<0.001) . Conclusion: Haplo HSCT has a survival advantage over MSDT in the treatment of B-ALL patients with pre MRD<0.1% .

PTCy-based Haploidentical vs Matched Unrelated Donor Peripheral Blood HSCT Using Myeloablative Targeted Busulfan-based Conditioning for Pediatric Acute Leukemia

Haploidentical related donor (HRD) is a common alternative donor strategy used when matched sibling or unrelated donors are not available for hematopoietic stem cell transplantation (HSCT). However, there have been no studies comparing HRD HSCT with post-transplant cyclophosphamide (PTCy) and matched unrelated donor (MUD) HSCT with antithymocyte globulin, using similar busulfan-based myeloablative conditioning regimen in pediatric acute leukemia. Here, we compared the outcomes in children and adolescents with high-risk acute leukemia after HRD HSCT with PTCy (n=35) and MUD HSCT (n=45) after targeted busulfan-based myeloablative conditioning using intensive pharmacokinetic monitoring. The median follow-up times of the HRD and MUD groups were 3.7 and 4.6 years, respectively. No engraftment failure was observed in both groups. The cumulative incidence of acute graft-versus-host disease (GVHD) grades II-IV (34.3% versus 48.9%, p=0.142), grades III-IV (2.9% vs. 8.9%, p=0.272), moderate to severe chronic GVHD (11.4% vs. 18.3%, p=0.417), relapse (25.6% vs. 28.0%, p=0.832), and non-relapse mortality (0% vs. 2.2%, p=0.420) were not significantly different between the two groups. The 3-year severe chronic GVHD-free/relapse-free (GRFS), leukemia-free (LFS) and overall survival (OS) rates in the HRD and MUD groups were 62.9% (95% confidence intervals [CI], 45.8%, 80.0%) versus 49.8% (95% CI, 34.9%, 64.7%; p=0.318), 74.4% (95% CI, 58.7%, 90.1%) versus 67.5% (95% CI, 53.4%, 81.6%; p=0.585), and 88.6% (95% CI, 78.0%, 99.2%) versus 83.7% (95% CI, 72.5%, 94.9%; p=0.968), respectively. In a subgroup analysis of acute lymphoblastic leukemia patients (HRD, n=17; MUD, n=26), the 3-year GRFS, LFS, and OS rates of the HRD and MUD groups were 49.4% (95% CI, 24.3%, 74.5%) versus 39.5% (95% CI, 19.7%, 59.3%; p=0.601), 61.8% (95% CI, 37.5%, 86.1%) versus 63.6% (95% CI, 44.4%, 82.8%; p=0.872), and 82.4% (95% CI, 64.4%, 100%) versus 84.2% (95% CI, 70.1%, 98.3%; p=0.445), respectively. In acute myeloid leukemia patients (HRD, n=16; MUD, n=16), the 3-year GRFS, LFS, and OS rates of the HRD and MUD groups were 80.8% (95% CI, 61.2%, 100%) versus 61.9% (95% CI, 37.8%, 86.0%; p=0.326), 87.1% (95% CI, 70.2%, 100%) versus 73.9% (95% CI, 51.8%, 96.0%; p=0.478), and 93.8% (95% CI, 81.8%, 100%) versus 85.6% (95% CI, 67.0%, 100%; p=0.628), respectively. Although the difference was not statistically significant and the number of patients was small, the promising outcomes of HRD HSCT in AML patients were encouraging. Our results demonstrated that HRD HSCT with PTCy using a targeted busulfan-based myeloablative conditioning shows outcomes similar to those of MUD HSCT with antithymocyte globulin. HRD HSCT with PTCy could be a feasible option for pediatric high-risk acute leukemia patients who lack an HLA-matched related or unrelated donor.

Comparison of non-first-degree related donors and first-degree related donors in haploidentical HSCT: a multi-centre retrospective analysis

The transplant outcomes of non-first-degree (NFD) related donors in haploidentical haematopoietic stem cell transplantation (haplo-HSCT) remain unclear. This multi-centre analysis compared NFD and first-degree (FD) related donors in haplo-HSCT using a low-dose anti-T-lymphocyte globulin/G-CSF-mobilised peripheral blood stem cell graft-based regimen. Ninety-nine patients (33 NFD; 66 FD) were included. All patients achieved myeloid and platelet engraftment. The 100-day cumulative incidence (CI) of aGVHD, 2-year CIs of relapse, cGVHD, and NRM, and 2-year probabilities of OS and GRFS were comparable between the two cohorts. In multivariate analysis, donor type (NFD vs. FD) had no impact on OS, PFS, GRFS, incidences of relapse, grade II-IV aGVHD or moderate-severe cGVHD. Older donor age was associated with a higher incidence of grade II-IV aGVHD (HR, 1.64, p = 0.03), moderate-severe cGVHD (HR, 1.92, p = 0.01) and worse GRFS (HR, 1.40, p = 0.02). A lower level of donor-recipient HLA matching was associated with a higher incidence of moderate-severe cGVHD (HR, 4.07, p = 0.02), and disease at complete remission was associated with better OS (HR, 0.21, p = 0.01) and PFS (HR, 0.3, p = 0.03). In conclusion, NFD donors may serve as feasible alternatives when FD donors are not available for haplo-HSCT.