Competitive repopulation and allo-immunologic pressure determine chimerism kinetics after T Cell-depleted allogeneic stem cell transplantation and donor lymphocyte infusion

After allogeneic stem cell transplantation (alloSCT), patient-derived stem cells that survived the pretransplantation conditioning compete with engrafting donor stem cells for bone marrow (BM) repopulation. In addition, donor-derived alloreactive T cells present in the stem cell product may favor establishment of complete donor-derived hematopoiesis by eliminating patient-derived lymphohematopoietic cells. T cell-depleted alloSCT with sequential transfer of potentially alloreactive T cells by donor lymphocyte infusion (DLI) provides a unique opportunity to selectively study how competitive repopulation and allo-immunologic pressure influence lymphohematopoietic recovery. This study aimed to determine the relative contribution of competitive repopulation and donor-derived anti-recipient alloimmunologic pressure on the establishment of lymphohematopoietic chimerism after alloSCT. In this retrospective cohort study of 281 acute leukemia patients treated according to a protocol combining alemtuzumab-based T cell-depleted alloSCT with prophy-lactic DLI, we investigated engraftment and quantitative donor chimerism in the BM and immune cell subsets. DLI-induced increase of chimerism and development of graft-versus-host disease (GVHD) were analyzed as complementary indicators for donor-derived anti-recipient alloimmunologic pressure. Profound suppression of patient immune cells by conditioning sufficed for sustained engraftment without necessity for myeloablative conditioning or development of clinically significant GVHD. Although 61% of the patients without any DLI or GVHD showed full donor chimerism (FDC) in the BM at 6 months after alloSCT, only 24% showed FDC in the CD4+ T cell compartment. In contrast, 75% of the patients who had received DLI and 83% of the patients with clinically significant GVHD had FDC in this compartment. In addition, 72% of the patients with mixed hematopoiesis receiving DLI converted to complete donor-derived hematopoiesis, of whom only 34% developed clinically significant GVHD. Our data show that competitive repopulation can be sufficient to reach complete donor-derived hematopoiesis, but that some alloimmunologic pressure is needed for the establishment of a completely donor-derived T cell compartment, either by the development of GVHD or by administration of DLI. We illustrate that it is possible to separate the graft-versus-leukemia effect from GVHD, as conversion to durable complete donor-derived hematopoiesis following DLI did not require induction of clinically significant GVHD. (c) 2023 The American Society for Transplantation and Cellular Therapy. Immunobiology of allogeneic stem cell transplantation and immunotherapy of hematological disease

Bortezomib maintenance after R-CHOP, cytarabine and autologous stem cell transplantation in newly diagnosed patients with mantle cell lymphoma, results of a randomised phase II HOVON trial

Rituximab-containing induction followed by autologous stem cell transplantation (ASCT) is the standard first-line treatment for young mantle cell lymphoma patients. However, most patients relapse after ASCT. We investigated in a randomised phase II study the outcome of a chemo-immuno regimen and ASCT with or without maintenance therapy with bortezomib. Induction consisted of three cycles R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, prednisone), two cycles high-dose cytarabine, BEAM (carmustine, etoposide, cytarabine, melphalan) and ASCT. Patients responding were randomised between bortezomib maintenance (1·3 mg/m2 intravenously once every 2 weeks, for 2 years) and observation. Of 135 eligible patients, 115 (85%) proceeded to ASCT, 60 (44%) were randomised. With a median follow-up of 77·5 months for patients still alive, 5-year event-free survival (EFS) was 51% (95% CI 42–59%); 5-year overall survival (OS) was 73% (95% CI 65–80%). The median follow-up of randomised patients still alive was 71·5 months. Patients with bortezomib maintenance had a 5-year EFS of 63% (95% CI 44–78%) and 5-year OS of 90% (95% CI 72–97%). The patients randomised to observation had 5-year PFS of 60% (95% CI, 40–75%) and OS of 90% (95% CI 72–97%). In conclusion, in this phase II study we found no indication of a positive effect of bortezomib maintenance after ASCT

Short-term efficacy and safety of antithymocyte globulin treatment in elderly patients with acquired aplastic anaemia

Immunobiology of allogeneic stem cell transplantation and immunotherapy of hematological disease

Feasibility, safety, and efficacy of early prophylactic donor lymphocyte infusion after T cell-depleted allogeneic stem cell transplantation in acute leukemia patients

Prophylactic donor lymphocyte infusion (DLI) starting at 6 months after T cell-depleted allogeneic stem cell transplantation (TCD-alloSCT) can introduce a graft-versus-leukemia (GvL) effects with low risk of severe graft-versus-host-disease (GvHD). We established a policy to apply low-dose early DLI at 3 months after alloSCT to prevent early relapse. This study analyzes this strategy retrospectively. Of 220 consecutive acute leukemia patients undergoing TCD-alloSCT, 83 were prospectively classified to have a high relapse risk and 43 were scheduled for early DLI. 95% of these patients received freshly harvested DLI within 2 weeks of the planned date. In patients transplanted with reduced intensity conditioning and an unrelated donor, we found an increased cumulative incidence of GvHD between 3 and 6 months after TCD-alloSCT for patients receiving DLI at 3 months compared to patients who did not receive this DLI (0.42 (95%Confidence Interval (95% CI): 0.14-0.70) vs 0). Treatment success was defined as being alive without relapse or need for systemic immunosuppressive GvHD treatment. The five-year treatment success in patients with acute lymphatic leukemia was comparable between high- and non-high-risk disease (0.55 (95% CI: 0.42-0.74) and 0.59 (95% CI: 0.42-0.84)). It remained lower in high-risk acute myeloid leukemia (AML) (0.29 (95% CI: 0.18-0.46)) than in non-high-risk AML (0.47 (95% CI: 0.42-0.84)) due to an increased relapse rate despite early DLI

Impact of rituximab on treatment outcomes of patients with angioimmunoblastic T-cell lymphoma; a population-based analysis

Background: Patients with angioimmunoblastic T-cell lymphoma (AITL) are treated with cyclophosphamide, doxorubicin, vincristine and prednisone with or without etoposide (CHO(E)P). In the majority of cases, Epstein-Barr virus (EBV)-positive B-cells are present in the tumour. There is paucity of research examining the effect of rituximab when added to CHO(E)P. In this nationwide, population-based study, we analysed the impact of rituximab on overall response rate (ORR), progression-free survival (PFS) and overall survival (OS) of patients with AITL. Methods: Patients with AITL diagnosed between 2014 and 2020 treated with >one cycle of CHO(E)P with or without rituximab were identified in the Netherlands Cancer Registry. Sur-vival follow-up was up to 1st February 2022. Baseline characteristics, best response during first-line treatment and survival were collected. PFS was defined as the time from diagnosis to relapse or to all-cause-death. OS was defined as the time from diagnosis to all-cause-death. Multivariable analysis for the risk of mortality was performed using Cox regression. Findings: Out of 335 patients, 146 patients (44%) received R-CHO(E)P. Rituximab was more frequently used in patients with a B-cell infiltrate (71% versus 89%, p < 0.01). The proportion of patients who received autologous stem cell transplantation (ASCT) was similar between CHO(E)P and R-CHO(E)P (27% versus 30%, respectively). The ORR and 2-year PFS for pa-tients who received CHO(E)P and R-CHO(E)P were 71% and 78% (p = 0.01), and 40% and 45% (p = 0.12), respectively. The 5-year OS was 47% and 40% (p = 0.99), respectively. In multi -variable analysis, IPI-score 3-5, no B-cell infiltrate and no ASCT were independent prognostic factors for risk of mortality, whereas the use of rituximab was not. Interpretation: Although the addition of rituximab to CHO(E)P improved ORR for patients with AITL, the PFS and OS did not improve. 2022 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)

Impact of rituximab on treatment outcomes of patients with angioimmunoblastic T-cell lymphoma; a population-based analysis

Background: Patients with angioimmunoblastic T-cell lymphoma (AITL) are treated with cyclophosphamide, doxorubicin, vincristine and prednisone with or without etoposide (CHO(E)P). In the majority of cases, Epstein-Barr virus (EBV)-positive B-cells are present in the tumour. There is paucity of research examining the effect of rituximab when added to CHO(E)P. In this nationwide, population-based study, we analysed the impact of rituximab on overall response rate (ORR), progression-free survival (PFS) and overall survival (OS) of patients with AITL. Methods: Patients with AITL diagnosed between 2014 and 2020 treated with >one cycle of CHO(E)P with or without rituximab were identified in the Netherlands Cancer Registry. Sur-vival follow-up was up to 1st February 2022. Baseline characteristics, best response during first-line treatment and survival were collected. PFS was defined as the time from diagnosis to relapse or to all-cause-death. OS was defined as the time from diagnosis to all-cause-death. Multivariable analysis for the risk of mortality was performed using Cox regression. Findings: Out of 335 patients, 146 patients (44%) received R-CHO(E)P. Rituximab was more frequently used in patients with a B-cell infiltrate (71% versus 89%, p < 0.01). The proportion of patients who received autologous stem cell transplantation (ASCT) was similar between CHO(E)P and R-CHO(E)P (27% versus 30%, respectively). The ORR and 2-year PFS for pa-tients who received CHO(E)P and R-CHO(E)P were 71% and 78% (p = 0.01), and 40% and 45% (p = 0.12), respectively. The 5-year OS was 47% and 40% (p = 0.99), respectively. In multi -variable analysis, IPI-score 3-5, no B-cell infiltrate and no ASCT were independent prognostic factors for risk of mortality, whereas the use of rituximab was not. Interpretation: Although the addition of rituximab to CHO(E)P improved ORR for patients with AITL, the PFS and OS did not improve. 2022 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).Immunobiology of allogeneic stem cell transplantation and immunotherapy of hematological disease

Treatment of patients with MYC rearrangement positive large B-cell lymphoma with R-CHOP plus phaselenalidomide: II HOVON trial results of a multicenter

P atients with MYC-rearrangement positive large B-cell lymphoma (MYC+ LBCL) have an inferior prognosis following standard first-line therapy with rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisolone (R-CHOP) compared to patients without MYC rearrangement. Although intensive chemotherapy regimens yield higher remission rates, toxicity remains a concern. Lenalidomide is an oral immunomodulatory drug which downregulates MYC and its target genes thereby providing support using lenalidomide as additional therapeutic option for MYC+ LBCL. A phase II trial was conducted evaluating the efficacy of lenalidomide (15 mg day 1-14) in combination with R-CHOP (R2CHOP) in newly diagnosed MYC+ LBCL patients identified through a nationwide MYCFISH screening program. The primary endpoint was complete metabolic response (CMR) on centrally reviewed 18 F-fluorodeoxyglucose ( 18 F-FDG) positron emission tomography (PET)-computer tomography (CT)-scan at end-of-treatment. Secondary endpoints were overall survival (OS), disease free survival (DFS) and event-free sur