There are limited data on the outcomes of autologous or allogeneic hematopoietic cell transplantation (HCT) in diffuse large B cell lymphoma transformed from follicular lymphoma. We analyzed transplantation outcomes in 141 subjects with biopsy-proven diffuse large B-cell lymphoma transformed from follicular lymphoma reported to the Center for International Blood and Marrow Transplant Research between 1990 and 2009. Two groups were identified: autologous HCT (auto-HCT; n = 108) and allogeneic HCT (allo-HCT; n = 33). Fewer auto-HCTs were done for transformed follicular lymphoma in 2003 to 2009, with a shift favoring allo-HCT. Auto-HCT was associated with a 1-year nonrelapse mortality (NRM) of 8% (95% confidence interval [CI], 4% to 14%), 5-year progression-free survival of 35% (95% CI, 26% to 45%), and 5-year overall survival of 50% (95% CI, 40% to 59%). In contrast, allo-HCT was associated with a 1-year NRM of 41% (95% CI, 23% to 58%), 5-year progression-free survival of 18% (95% CI, 6% to 35%), and 5-year overall survival of 22% (95% CI, 8% to 41%). Auto-HCT for transformed follicular lymphoma achieves sustained remission in a high proportion of subjects. The high NRM of allo-HCT offset any benefit that might be associated with this transplantation modality.

As outcomes of hematopoietic stem cell transplantation have improved over time, disease relapse has emerged as the most significant cause of treatment failure. Cellular therapy represents an alternative therapeutic approach, not only to treat or prevent disease relapse after hematopoietic stem cell transplantation, but also conceivably to help patients achieve remission prior to transplantation or as consolidation therapy for high-risk patients with hematologic malignancies. Of the many cellular therapies available, infusion of NK cells may be the most promising approach against malignant or virally infected cells owing to strong innate activity of NK cells in vitro and in vivo. Only limited clinical data exists mostly from feasability studies of inadequate size to demonstrate clinical benefit. Here, we discuss the current status of clinical investigation using NK cell therapy for patients with hematologic malignancies undergoing hematopoietic stem cell transplantation.

T-cell/histiocyte–rich large B-cell lymphoma (THRLBCL) is a rare histologic variant of LBCL. Limited data regarding CD19–directed chimeric antigen receptor T-cell (CART) therapy in relapsed/refractory (R/R) THRLBCL suggest poor efficacy. We investigated CART outcomes for R/R THRLBCL through the Center for International Blood and Marrow Transplant Research registry. A total of 58 adult patients with R/R THRLBCL who received commercial CD19-CART therapy between 2018 and 2022 were identified. Most patients (67%) had early relapse of disease (45% primary refractory) with a median of 3 (range, 1-7) prior therapies and were treated with axicabtagene ciloleucel (69%). At median follow-up of 23 months after CART therapy, 2-year overall and progression-free survival were 42% (95% confidence interval [CI], 27-57) and 29% (95% CI, 17-43), respectively. In univariable analysis, poor performance status before CART therapy was associated with higher mortality (hazard ratio, 2.35; 95%CI, 1.02-5.5). The 2-year cumulative incidences of relapse/progression and nonrelapse mortality were 69% and 2%, respectively. Grade ≥3 cytokine release syndrome and immune effector cell–associated neurologic syndrome occurred in 7% and 15% of patients, respectively. In this largest analysis of CD19-CART therapy for R/R THRLBCL, ∼30% of patients were alive and progression free 2 years after CART therapy. Despite a high incidence of progression (69% at 2 years), these results suggest a subset of patients with R/R THRLBCL may have durable responses with CARTs.

We evaluate the impact of donor types on outcomes of hematopoietic cell transplantation (HCT) in myelofibrosis, using the Center for International Blood and Marrow Transplant Research registry data for HCTs done between 2013 and 2019. In all 1597 patients, the use of haploidentical donors increased from 3% in 2013 to 19% in 2019. In study-eligible 1032 patients who received peripheral blood grafts for chronic-phase myelofibrosis, 38% of recipients of haploidentical HCT were non-White/Caucasian. Matched sibling donor (MSD)–HCTs were associated with superior overall survival (OS) in the first 3 months (haploidentical hazard ratio [HR], 5.80 [95% confidence interval (CI), 2.52-13.35]; matched unrelated (MUD) HR, 4.50 [95% CI, 2.24-9.03]; mismatched unrelated HR, 5.13 [95% CI, 1.44-18.31]; P < .001). This difference in OS aligns with lower graft failure with MSD (haploidentical HR, 6.11 [95% CI, 2.98-12.54]; matched unrelated HR, 2.33 [95% CI, 1.20-4.51]; mismatched unrelated HR, 1.82 [95% CI, 0.58-5.72]). There was no significant difference in OS among haploidentical, MUD, and mismatched unrelated donor HCTs in the first 3 months. Donor type was not associated with differences in OS beyond 3 months after HCT, relapse, disease-free survival, or OS among patients who underwent HCT within 24 months of diagnosis. Patients who experienced graft failure had more advanced disease and commonly used nonmyeloablative conditioning. Although MSD-HCTs were superior, there is no significant difference in HCT outcomes from haploidentical and MUDs. These results establish haploidentical HCT with posttransplantation cyclophosphamide as a viable option in myelofibrosis, especially for ethnic minorities underrepresented in the donor registries.

RGI-2001, a glycolipid that binds CD1d receptor of antigen-presenting cells, can activate invariant natural killer T (NKT) cells and stimulate cytokine-dependent proliferation of regulatory T cells (Tregs). This open-label, multicenter phase 2b trial evaluated the safety and efficacy of RGI-2001 in combination with standard graft-versus-host disease (GVHD) prophylaxis in participants receiving myeloablative allogeneic hematopoietic cell transplantation (HCT). RGI-2001 was infused at a dose of 100 μg/kg for 6 weekly doses. The primary end point was grade 2 to 4 acute GVHD by day 100. A total of 49 participants received RGI-2001 in combination with tacrolimus and methotrexate. RGI-2001 was well tolerated, with no serious infusion reactions. Sixteen participants experienced grade ≥3 treatment-related adverse events, including decreased appetite, leukopenia, thrombocytopenia, and stomatitis. The cumulative incidence of grade 2 to 4 and 3 to 4 acute GVHD were 24.9% and 4.1%, respectively. Compared with the controls from the Center for International Blood and Marrow Research Transplant registry, participants receiving RGI-2001 experienced superior clinical outcomes, including day-180 grade 2 to 4 acute GVHD-free survival (70.8% vs 50.7%; adjusted hazard ratio, 0.45; 95% confidence interval, 0.30-0.68). Increasing NKT and Treg populations were observed after HCT, consistent with the proposed action of RGI-2001. In conclusion, RGI-2001 was well tolerated and was associated with low rates of acute GVHD and encouraging survival after myeloablative HCT. These results support strategies that target NKT and Treg cell populations to augment immunologic changes in allogeneic HCT recipients. This trial was registered at www.clinicaltrials.gov as #NCT04014790.

Allogeneic hematopoietic stem cell transplantation (SCT) is often the only curative option for many patients with malignant and benign hematological stem cell disorders. However, some issues are still of concern regarding finding a donor like shrinking family sizes in many societies, underrepresentation of the ethnic minorities in the registries, genetic variability for some races, and significant delays in obtaining stem cells after starting the search. So there is a considerable need to develop alternate donor stem cell sources. The rapid and near universal availability of the haploidentical donor is an advantage of the haploidentical SCT and an opportunity that is being explored currently in many centers especially using T cell replete graft and posttransplant cyclophosphamide. This is probably because it does not require expertise in graft manipulation and because of the lower costs. However, there are still lots of unanswered questions, like the effect of use of bone marrow versus peripheral blood as the source of stem cells on graft-versus-host disease, graft versus tumor, overall survival, immune reconstitution, and quality of life. Here we review the available publications on bone marrow and peripheral blood experience in the haploidentical SCT setting. Allogeneic hematopoietic stem cell transplantation (SCT) is often the only curative option for many patients with malignant and benign hematological stem cell disorders. However, some issues are still of concern regarding finding a donor like shrinking family sizes in many societies, underrepresentation of the ethnic minorities in the registries, genetic variability for some races, and significant delays in obtaining stem cells after starting the search. So there is a considerable need to develop alternate donor stem cell sources. The rapid and near universal availability of the haploidentical donor is an advantage of the haploidentical SCT and an opportunity that is being explored currently in many centers especially using T cell replete graft and posttransplant cyclophosphamide. This is probably because it does not require expertise in graft manipulation and because of the lower costs. However, there are still lots of unanswered questions, like the effect of use of bone marrow versus peripheral blood as the source of stem cells on graft-versus-host disease, graft versus tumor, overall survival, immune reconstitution, and quality of life. Here we review the available publications on bone marrow and peripheral blood experience in the haploidentical SCT setting.