Comparable outcome after haploidentical and HLA-matched allogeneic stem cell transplantation for high-risk acute myeloid leukemia following sequential conditioning-a matched pair analysis.

In acute myeloid leukemia (AML), primary refractory or relapsed disease, secondary AML, and leukemia with unfavorable genetics are considered high-risk AML (hrAML), with allogeneic stem cell transplantation (SCT) representing the standard treatment. Sequential conditioning has been successfully used for SCT in hrAML in HLA-matched transplants, and found its way into HLA-haploidentical SCT (haplo-SCT) later on. Hence, sequential conditioning had become standard for all patients with hrAML in our two centers, regardless of donor type. Thereby, HLA-matched family or unrelated transplants were first/second choice, post-transplant cyclophosphamide (PTCY)-based haplo-SCT was chosen in patients missing matched donors or requiring urgent transplantation. To compare the outcome after HLA-matched and haplo-SCT for hrAML following sequential conditioning, we performed a retrospective, matched-pair comparison, using disease stage, genetic subgroups and age as matching criteria. Thirty-four well-matched pairs were identified. At SCT, patients (median age 54 years) were untreated (9%), had remission (13%), or active disease (78%). Three-year overall and leukemia-free survival (OS/LFS) of the entire cohort was 56 ± 7%/49 ± 7%, without significant differences between donor types (OS after HLA-matched/haplo-SCT 62 ± 10%/52 ± 9% (p = 0.21), LFS 53 ± 10%/46 ± 9% (p = 0.26)). Similarly, the cumulative incidence of relapse, non-relapse-mortality and chronic GvHD, as well as GvHD-free, relapse-free survival (GRFS), and chronic GvHD-free, relapse-free survival (cGRFS), were comparable. However, a higher incidence of acute GvHD ≥ II° was observed after HLA-matched SCT (15 ± 1% versus 50 ± 2%, p = 0.001). In conclusion, sequential conditioning SCT achieved remarkable results in hrAML, independently from donor type. PTCY-based haplo-SCT produced results that were comparable to HLA-matched SCT and can be used as an alternative option.

Sequential HLA-haploidentical transplantation utilizing post-transplantation cyclophosphamide for GvHD prophylaxis in high-risk and relapsed/refractory AML/MDS.

This study evaluates the role of sequential therapy in HLA-haploidentical transplantation (haplo-HSCT) of high-risk, relapsed/refractory AML/MDS. We analyzed the course of 33 adults with active disease at time of transplantation (AML n = 30; MDS n = 3; median age 58 years, range: 32-71). Sequential therapy consisted of cytoreductive chemotherapy (FLAMSA n = 21; clofarabine n = 12) applied shortly prior to reduced intensity conditioning for T-cell-replete haplo-HSCT using post-transplantation cyclophosphamide as GvHD prophylaxis. No graft rejection was observed. Complete remission at day +30 was achieved in 97% of patients. CI of acute GvHD grade II-IV and chronic GvHD was 24% (no grade IV) and 23%, respectively. NRM at 1 and 3 years was 15%, each. Severe regimen-related toxicities (grade III-IV) were observed in 58%, predominantly involving the gastrointestinal tract (diarrhea 48%, mucositis 15%, transient elevation of transaminases 18%). Probability of relapse at 1 and 3 years was 28% and 35%. At a median follow-up of 36 months, the estimated 1- and 3-year overall survival was 56% and 48%. Disease-free survival was 49% and 40%, respectively. At 3 years, GvHD and relapse-free survival (GRFS) was 24% while chronic GvHD and relapse-free survival (CRFS) was 29%. Thus, our results indicate that sequential haplo-HSCT is an effective salvage treatment providing high anti-leukemic activity, favorable tolerance, and acceptable toxicity in patients suffering from advanced AML/MDS.

Virus infection in HLA-haploidentical hematopoietic stem cell transplantation: incidence in the context of immune recovery in two different transplantation settings.

We retrospectively compared the incidence of virus infections and outcome in the context of immune reconstitution in two different HLA-haploidentical transplantation (haplo-HSCT) settings. The first was a combined T-cell-replete and T-cell-deplete approach using antithymocyte globulin (ATG) prior to transplantation in patients with hematological diseases (cTCR/TCD group, 28 patients; median age 31 years). The second was a T-cell-replete (TCR) approach using high-dose posttransplantation cyclophosphamide (TCR/PTCY group, 27 patients; median age 43 years). The incidence of herpesvirus infection was markedly lower in the TCR/PTCY (22 %) than in the cTCR/TCD group (93 %). Recovery of CD4+ T cells on day +100 was faster in the TCR/PTCY group. CMV reactivation was 30 % in the TCR/PTCY compared to 57 % in the cTCR/TCD group, and control with antiviral treatment was superior after TCR/PTCY transplantation (100 vs 50 % cTCR/TCD). Twenty-five percent of the patients in the cTCR/TCD group but no patient in the TCR/PTCY group developed PTLD. While 1-year OS was not different (TCR/PTCY 59 % vs cTCR/TCD 39 %; p = 0.28), virus infection-related mortality (VIRM) was significantly lower after TCR/PTCY transplantation (1-year VIRM, 0 % TCR/PTCY vs 29 % cTCR/TCD; p = 0.009). On day +100, predictors of better OS were lymphocytes >300/µl, CD3+ T cells >200/µl, and CD4+ T cells >150/µl, whereas the application of steroids >1 mg/kg was correlated with worse outcome. Our results suggest that by presumably preserving antiviral immunity and allowing fast immune recovery of CD4+ T cells, the TCR approach using posttransplantation cyclophosphamide is well suited to handle the important issue of herpesvirus infection after haplo-HSCT.

Treosulfan-Versus Melphalan-Based Reduced Intensity Conditioning in HLA-Haploidentical Transplantation for Patients ≥ 50 Years with Advanced MDS/AML.

Relapse and regimen-related toxicities remain major challenges in achieving long-term survival, particularly among older patients with high-risk myelodysplastic syndrome (MDS) or acute myeloid leukemia (AML) undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT). Previous studies have demonstrated the feasibility of treosulfan-based conditioning, noting stable engraftment and low non-relapse mortality (NRM) in patients undergoing HLA-matched allo-HSCT. However, data on treosulfan-based conditioning in the HLA-haploidentical transplantation (HaploT) setting are limited. We retrospectively compared conditioning with fludarabine-cyclophosphamide (FC)-melphalan (110 mg/m2) and FC-treosulfan (30 g/m2) prior to HaploT using post-transplantation cyclophosphamide (PTCy) in patients with high-risk MDS/AML patients ≥ 50 years, transplanted from 2009-2021 at our institution (n = 80). After balancing patient characteristics by a matched-pair analysis, we identified twenty-one matched pairs. Two-year OS and LFS were similar among the groups (OS 66% and LFS 66%, p = 0.8 and p = 0.57). However, FC-melphalan was associated with a significantly lower probability of relapse compared to FC-treosulfan (0% vs. 24%, p = 0.006), counterbalanced by a higher NRM (33% vs. 10%, p = 0.05). Time to engraftment and incidences of acute and chronic graft-versus-host disease (GvHD) did not differ significantly. In conclusion, HaploT using FC-treosulfan in combination with PTCy in patients aged ≥50 years with MDS/AML appears safe and effective, particularly in advanced disease stages. We confirm the favorable extramedullary toxicity profile, allowing for potential dose intensification to enhance antileukemic activity.

Feasibility of clofarabine cytoreduction followed by haploidentical hematopoietic stem cell transplantation in patients with relapsed or refractory advanced acute leukemia.

Clofarabine is a novel purine nucleoside analogue with immunosuppressive and anti-leukemic activity in acute lymphoblastic and myeloid leukemia (AML, ALL). This retrospective study was performed to evaluate the feasibility and anti-leukemic activity of a sequential therapy using clofarabine for cytoreduction followed by conditioning for haploidentical hematopoietic stem cell transplantation (HSCT) in patients with non-remission acute leukemia. Patients received clofarabine (5 × 30 mg/m² IV) followed by a T cell replete haploidentical transplantation for AML (n = 15) or ALL (n = 3). Conditioning consisted of fludarabine, cyclophosphamide plus either melphalan, total body irradiation or treosulfan/etoposide. High-dose cyclophosphamide was administered for post-grafting immunosuppression. Neutrophil engraftment was achieved in 83 % and complete remission in 78% at day +30. The rate of acute graft versus host disease (GvHD) grade II-IV was 22%, while chronic GvHD occured in five patients (28%). Non-relapse mortality (NRM) after 1 year was 23%. At a median follow-up of 19 months, estimated overall survival and relapse-free survival at 1 year from haploidentical HSCT were 56 and 39%, respectively. Non-hematological regimen-related grade III-IV toxicity was observed in ten patients (56%) and included most commonly transient elevation of liver enzymes (44%), mucositis (40%), and skin reactions including hand-foot syndrome (17%), creatinine elevation (17%), and nausea/vomiting (17%). The concept of a sequential therapy using clofarabine for cytoreduction followed by haploidentical HSCT proved to be feasible and allows successful engraftment, while providing an acceptable toxicity profile and anti-leukemic efficacy in patients with advanced acute leukemia. NRM and rate of GvHD were comparable to results after HSCT from HLA-matched donors.

PTCY-Based Haploidentical Donor Transplantation versus HLA-Matched Related and Unrelated Donor Transplantations in Patients with Refractory or Relapsed Lymphoma-A Matched-Pair Analysis.

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) has demonstrated its potential as a curative option for patients with r/r lymphoma. With the introduction of post-transplant cyclophosphamide-based (PTCY) graft-versus-host disease (GvHD) prophylaxis, allo-HCT using haploidentical related donors (Haplo-HSCT) has emerged as a valuable alternative for patients without an available HLA-matched donor. In this study, we compared intermediate and long-term outcomes between Haplo-HSCT and HLA-matched related donor (MRD) and unrelated donor (URD) transplantations in 16 matched pairs using age, disease status, lymphoma classification and performance status as matching criteria. Of note, 88% of patients in each group presented with active disease at the time of conditioning. After a median follow-up of >10 years, 10-year overall and progression-free survival and non-relapse mortality incidence after Haplo-HSCT were 31%, 25% and 38%, respectively, and did not differ compared to the values observed in MRD-HSCT and URD-HSCT. A remarkable lower incidence of acute GvHD ≥ II and moderate and severe chronic GvHD was observed after Haplo-HSCT compared to MRD-HSCT (50%/50%, p = 0.03/0.03) and URD-HSCT (44%/38%, p = 0.04/0.08), resulting in slightly higher 10-year GvHD-free and relapse-free survival (25%) and chronic GvHD-free and relapse-free survival (25%) in the Haplo-HSCT group. In conclusion, Haplo-HSCT is an effective treatment in patients with non-remission NHL. Given its advantage of immediate availability, haploidentical donors should be preferably used in patients with progressive disease lacking an HLA-matched related donor.

Effective and long-term control of EBV PTLD after transfer of peptide-selected T cells.

Posttransplantation lymphoproliferative disease (PTLD) associated with Epstein-Barr virus (EBV) is a life-threatening complication after allogeneic hematopoietic stem cell transplantation. PTLD is efficiently prevented by adoptive transfer of EBV-specific T cells from the donor. To make EBV-specific T cells available in urgent clinical situations, we developed a rapid protocol for their isolation by overnight stimulation of donor blood cells with peptides derived from 11 EBV antigens, interferon-gamma surface capture, and immunomagnetic separation. Six patients with PTLD received 1 transfusion of EBV-specific T cells. No response was seen in 3 patients who had late-stage disease with multiorgan dysfunction at the time of T-cell transfer. In 3 patients who received T cells at an earlier stage of disease, we observed complete and stable remission of PTLD. Two patients have remained free from EBV-associated disease for more than 2 years. CD8(+) T cells specific for EBV early antigens rapidly expanded after T-cell transfer, temporarily constituted greater than 20% of all peripheral blood lymphocytes, and were maintained throughout the observation period. Thus, a rapid and sustained reconstitution of a protective EBV-specific T-cell memory occurred after the infusion of small numbers of directly isolated EBV-specific T cells.

Occurrence, risk factors and outcome of adenovirus infection in adult recipients of allogeneic hematopoietic stem cell transplantation.

BACKGROUND: Adenovirus (ADV) infections can have a high mortality in immunocompromised patients and are difficult to treat. OBJECTIVES AND STUDY DESIGN: We retrospectively analyzed occurrence and risk factors of ADV infection in 399 adults with hematological disorders undergoing hematopoietic stem cell transplantation (allo-HSCT), focusing on alternative donor transplantation (ADT) and disseminated disease. RESULTS: ADV infection occurred in 42 patients (10.5%). Disease was localized in 18 and disseminated in 6 patients. ADV infection was observed in 15% after ADT, performed in 29% of all recipients, and was less frequent (6%) in T-cell-replete (TCR) haploidentical transplantation using post-transplantation cyclophosphamide (PTCY) than in other ADT protocols. Lower age, the use of alternative donor grafts and acute graft-versus-host disease (GvHD)≥grade II were risk factors for ADV infection. After failure of standard antiviral treatment, three patients with disseminated ADV disease received one dose of ADV-specific T cells, resulting in virological response in 2/3 patients, clearance of ADV viremia in 2/2 patients, and survival of 1/3 patients; both patients with pneumonia died. CONCLUSIONS: ADV infection was of moderate occurrence in our adult recipients of allo-HSCT despite a high proportion of potential high-risk patients receiving ADT. TCR strategies using PTCY might limit ADV complications in haploidentical transplantation. Despite feasible adoptive therapy strategies, outcome of disseminated disease remains dismal.