Conditioning regimens for allotransplants for diffuse large B-cell lymphoma: myeloablative or reduced intensity?

Allogeneic stem cell transplantation and CAR-T in B-cell Non-Hodgkin Lymphoma: a two-center experience and review of the literature

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is still a potentially curative option for B-cell Non-Hodgkin Lymphoma (B-NHL) in the modern immunotherapy era. The objective of this study was to analyze long-term outcomes of patients with B-NHL who received allo-HSCT. We analyzed overall survival (OS), progression-free survival (PFS) and graft versus host disease (GVHD) relapse-free survival (GRFS) in 53 patients undergoing allo-HSCT from two institutions. The median follow-up of the study was 72 months (range 29-115 months). The median number of lines of therapy before allo-HSCT was 3 (range 1-6) and twenty-eight patients (53%) had received a previous autologous transplant. The 3-year PFS, OS and GRFS were 55%, 63%, and 55%, respectively. One-year non-relapse mortality was 26%. Karnofsky Performance Scale < 90 was associated with worse OS in multivariable analysis. A non-comparative analysis of a cohort of 44 patients with similar characteristics who received chimeric antigen receptor T-cell therapy was done, showing a 1-year PFS and OS were 60% and 66%, respectively. Our data shows that allo-HSCT is still a useful option for treating selected patients with R/R B-NHL. Our retrospective analysis and review of the literature demonstrate that allo-HSCT can provide durable remissions in a subset of patients with R/R B-NHL.

Transplantation and Cellular Therapy for Older Adults-The MSK Approach

PURPOSE OF REVIEW

Hematologic malignances more commonly affect older individuals and often present with advanced, higher risk disease than younger patients. Allogeneic and autologous hematopoietic cell transplantation is well-established treatment modalities with curative potential following either frontline treatments for these diseases or salvage therapy in the relapsed or refractory setting. More recently, novel cellular immunotherapy such as chimeric antigen receptor T-cell therapy has been shown to lead to high response rate and durable remission in many patients with advanced blood cancers.

RECENT FINDINGS

Given unique characteristics of older patients, how best to deliver these higher-intensity and time sensitive treatment modalities for them remains challenging. Moreover, their short-term and potential long-term impact on their functional status, cognitive status, and quality of life may be significant considerations for many older patients. All these issues contributed to the lack of access and significant underutilization of these potential curative treatment strategies. In this review, we present up to date evidence to support potential benefits of transplantation and cellular therapy for older adults, their steady improving outcomes, and most importantly, highlight the use of geriatric assessment to help select appropriate older patients and optimize them prior to and following transplantation and cellular therapy. We specifically describe our approach at Memorial Sloan Kettering Cancer Center and encouraging early results from its implementation.

Therapeutic options for large B-cell lymphoma relapsing after CD19-directed CAR T-cell therapy

In recent years, chimeric antigen receptor T-cell therapy (CAR T) has revolutionized the treatment landscape for large B cell lymphoma (LBCL), demonstrating remarkable efficacy and ushering a new era of therapeutic possibilities. However, a subset of patients may not achieve the desired response with CAR T. This review examines strategies aimed at optimizing outcomes for patients who relapse or progress after CAR T. Available data on utilization of CD19-directed monoclonal antibodies and antibody drug conjugates have shown limited efficacy in this setting. Moreover, bispecific antibodies have also emerged as an alternative therapy in relapsed and or refractory LBCL, but long-term follow up treated cases post-CAR T failure are lacking. Several observational studies have shown efficacy of allogeneic hematopoietic cell transplantation, but attainment of a complete remission prior to allografting is a prerequisite to achieve durable remissions. As we navigate the intricate landscape of treatment of post CAR T failure, it becomes evident that this represents a therapeutic challenge which necessitates a multifaceted approach.

Allogeneic hematopoietic stem cell transplantation for B-cell lymphoma in Taiwan

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is considered for patients with high-risk B-cell lymphoma and relapsed or refractory disease. This study aimed to analyze the long-term follow-up data of patients who underwent allo-HSCT in Taiwan. This was a retrospective observational study using data from the Taiwan Society of Blood and Marrow Transplantation database. A total of 105 patients who underwent allo-HSCT because of high-risk, relapsed, or refractory disease between 2010 and 2019 were included. Forty-five percent of the patients previously underwent autologous stem cell transplantation (ASCT). The median follow-up duration was 18.6 months. The probability of 3-year progression-free survival and overall survival (OS) was 34.5% and 37%, respectively. The probability of 1-year non-relapse mortality was 31.4%, and the major cause was infection (75.8%). The multivariable analysis showed that not in remission at the time of transplantation and the absence of graft-versus-host disease (GVHD) were factors associated with inferior OS. The probability of 3-year OS in patients with diffuse large B-cell lymphoma who underwent allo-HSCT and allo-HSCT after ASCT was 40.2% and 25.2%, respectively. Allo-HSCT could be a salvage therapeutic option for relapsed or refractory B-cell lymphoma. Complete remission at the time of allo-HSCT and the presence of GVHD are independent variables for overall survival.

Results of a Phase II Trial of Allogeneic Hematopoietic Stem Cell Transplantation Using 90Y-Ibritumomab Tiuxetan (Zevalin) in Combination With Fludarabine and Melphalan in Patients With High-Risk B-Cell Non-Hodgkin's Lymphoma

BACKGROUND

Allogeneic hematopoietic stem cell transplantation (alloHCT) is potentially curative for relapsed/refractory (r/r) B-cell non-Hodgkin's lymphoma (B-cell NHL). However, relapse remains a major cause of treatment failure, especially in patients with either positron emission tomography (PET)-positive and/or chemoresistant disease prior to alloHCT. 90Y-ibritumomab tiuxetan (Zevalin) is a radiolabeled anti-CD20 antibody which is a safe and effective therapy in multiple histologic subtypes of B-cell NHL and has also been incorporated in both autologous HCT (autoHCT) and alloHCT conditioning regimens.

OBJECTIVES

The purpose of this study was to evaluate the efficacy and confirm the safety of the radiolabeled anti-CD20 antibody ibritumomab tiuxetan (Zevalin) combined with the reduced intensity conditioning (RIC) regimen of fludarabine and melphalan (Flu/Mel) in patients with high-risk B-cell NHL.

STUDY DESIGN

We conducted a phase II trial (NCT00577278) of Zevalin with Flu/Mel in patients with high-risk B-cell NHL. We enrolled 41 patients from October 2007 to April 2014, all of whom had either a fully matched sibling or 8/8 or 7/8 matched unrelated donor (MUD). Patients received 111In-Zevalin (5.0 mCi) on day -21 pre-HCT, followed by 90Y-Zevalin (0.4 mCi/kg) on day -14. Fludarabine (25 mg/m2 daily) was given from days -9 to -5 and melphalan (140 mg/m2) was administered on day -4. All patients received rituximab 250 mg/m2 on day +8 and an additional dose on either day +1 or -21 depending on the baseline rituximab level. Patients with a low rituximab level were given rituximab on days -21 and -15. All patients received tacrolimus/sirolimus (T/S) with or without methotrexate (MTX) for graft-versus-host disease (GVHD) prophylaxis starting on day -3, and stem cells were infused on day 0.

RESULTS

The 2-year overall survival (OS) and progression-free survival (PFS) for all patients were 63% and 61%, respectively. The incidence of relapse at 2 years was 20%. Nonrelapse mortality (NRM) at day +100 and 1 year were 5% and 12%, respectively. The overall cumulative incidence of grade II-IV and III-IV acute GVHD (aGVHD) were 44% and 15%, respectively. Extensive chronic GVHD (cGVHD) occurred in 44% of patients. On univariate analysis, histology (diffuse large B cell lymphoma (DLBCL) vs. others) was negatively predictive for OS (P = .0013) and PFS (P = .0004), while histology (DLBCL vs. others, P = .0128) predicted for relapse. PET positivity pre-HCT did not correlate with any of the efficacy endpoints.

CONCLUSION

Addition of Zevalin to Flu/Mel is safe and effective in high-risk NHL and met the prespecific endpoint. Results were suboptimal in patients with DLBCL.

How I treat refractory/relapsed diffuse large B-cell lymphomas with CD19-directed chimeric antigen receptor T cells

Chimeric antigen receptor (CAR) T cells targeting CD19 represent a promising salvage immunotherapy for relapsed/refractory diffuse large B-cell lymphoma (R/R DLBCL), offering ~40% of long-term responses. In everyday clinical practice, haematologists involved in CAR T cell treatment of patients with R/R DLBCL have to deal with diagnostically complex cases and difficult therapeutic choices. The availability of novel immunotherapeutic agents for R/R DLBCL and recent advances in understanding CAR T-cell failure mechanisms demand a rational approach to identify the best choice for bridging therapy and managing post-CAR T-cell therapy relapses. Moreover, positron emission tomography/computerised tomography may result in false-positive interpretation, highlighting the importance of post-treatment biopsy. In this review, we discuss all above issues, presenting four instructive cases, with the aim to provide criteria and new perspectives for CAR T-cell treatment of DLBCL.

Allogeneic Hematopoietic Cell Transplantation after Chimeric Antigen Receptor T Cell Therapy in Large B Cell Lymphoma

Anti-CD19 chimeric antigen receptor T cell (CAR-T) therapy has transformed the care of patients with relapsed/refractory large B cell lymphoma (LBCL). However, approximately 60% of CAR-T recipients ultimately will experience disease recurrence or progression. Salvage therapies after CAR-T treatment failures are of limited efficacy and have a short duration of response. The objective of the present study was to evaluate the role of allogeneic hematopoietic cell transplantation (allo-HCT) after CAR-T therapy in LBCL patients. This was a multicenter observational study reporting the outcome of 39 adult LBCL patients who underwent allo-HCT following anti-CD19 CAR-T therapy. The median patient age was 47 years (range, 20 to 68 years). HLA-matched sibling, HLA-matched unrelated, and alternative donors were used in 36%, 36%, and 28% of transplantations, respectively. Conditioning regimens were primarily of low or intermediate intensity. Disease status at allo-HCT was complete response in 41%, partial response in 38%, and progressive disease in 21%. Allo-HCT was performed at a median of 127 days (range, 82 to 206 days) after CAR-T therapy. A high incidence of hepatic toxicity (28%), including sinusoidal obstruction syndrome (15.4%; 95% confidence interval; [CI], 6.2% to 28.5%), was observed. The 1-year cumulative incidence of grade II-IV and grade III-IV acute graft-versus-host disease (GVHD) was 38.5% (95% CI, 23.2% to 53.6%) and 15.4% (95% CI, 6.1% to 28.5%), respectively. The 2-year cumulative incidence of moderate-severe chronic GVHD was 11.1% (95% CI, 3.3% to 24.3%). Overall, 2-year nonrelapse mortality and relapse/progression incidence were 26% (95% CI, 13% to 41%) and 43% (95% CI, 27% to 59%), respectively. With a median follow-up of 32 months, the 2-year overall survival (OS) and progression-free survival (PFS) were 45% (95% CI, 31% to 66%) and 31% (95% CI, 19% to 50%), respectively. In multivariable analyses, pre-HCT elevated lactate dehydrogenase level and transformed lymphoma were predictive of OS and PFS, respectively. Our data suggest that allo-HCT after anti-CD19 CAR-T treatment failure is feasible with a relatively promising efficacy but possibly high toxicity rate.

Allogeneic transplant following CAR T-cell therapy for large B-cell lymphoma

Allogeneic hematopoietic cell transplantation (alloHCT) can potentially salvage large B-cell lymphoma (LBCL) patients experiencing treatment failure after chimeric antigen receptor T-cell therapy (CAR T). Nonetheless, data on the efficacy and toxicities of alloHCT after receipt of CAR T are limited. We report a multicenter retrospective study assessing the safety, toxicities, and outcomes of alloHCT in LBCL patients following CAR T failure. Eighty-eight patients with relapsed, refractory LBCL received an alloHCT following anti-CD19 CAR T failure. The median number of lines of therapy between CAR T infusion and alloHCT was one (range, 0-7). Low intensity conditioning was used in 77% (n=68) and peripheral blood was the most common graft source (86%, n=76). The most common donor types were matched unrelated donor (39%), followed by haploidentical (30%) and matched related donor (26%). Median follow-up of survivors was 15 months (range, 1-72). One-year overall survival, progression-free survival, and graft-versus-host disease-free relapse-free survival were 59%, 45%, and 39% respectively. One-year non-relapse mortality and progression/relapse were 22% and 33% respectively. On multivariate analysis, <2 lines of intervening therapy between CAR T and alloHCT and complete response at time of alloHCT were associated with better outcomes. In conclusion, alloHCT after CAR T failure can provide durable remissions in a subset of patients.

Fludarabine plus reduced-intensity busulfan versus fludarabine plus myeloablative busulfan in patients with non-Hodgkin lymphoma undergoing allogeneic hematopoietic cell transplantation

Allogeneic hematopoietic cell transplantation (HCT) offers a possible cure for patients with relapsed and refractory non-Hodgkin lymphoma (NHL) through potentially beneficial graft versus lymphoma effects. However, allogeneic HCT is associated with high nonrelapse mortality (NRM). Fludarabine with reduced-intensity busulfan (Flu/Bu2) and myeloablative busulfan (Flu/Bu4) are commonly used in conditioning regimens for allogeneic HCT; however, data on their use in patients with NHL is limited. We investigated the effect of busulfan dose on outcomes by comparing Flu/Bu2 and Flu/Bu4 in patients with NHL who underwent allogeneic HCT. Our study included 415 adult patients with NHL who received Flu/Bu2 (315 patients) or Flu/Bu4 (100 patients) between January 2008 and December 2019. All patients were enrolled in the Transplant Registry Unified Management Program 2 of the Japanese Data Center for Hematopoietic Cell Transplantation. The primary endpoint was the 5-year overall survival (OS). To minimize potential confounding factors that may influence outcomes, we performed propensity score matching. The 5-year OS was 50.6% (95% confidence interval (CI), 39.4%-60.8%) and 32.2% (95% CI, 22.4-42.4%) in the Flu/Bu2 and Flu/Bu4 groups, respectively (p = 0.006). The hazard ratio comparing the two groups was 2.13 (95% CI, 1.30-3.50; p = 0.003). Both groups had a similar 5-year cumulative incidence of relapse (38.2% vs 41.3%; p = 0.581), and the Flu/Bu4 group had a higher cumulative incidence of 5-year NRM (15.7% vs 31.9%; p = 0.043). In this study, Flu/Bu4 was associated with worse OS compared with Flu/Bu2 because of high NRM in patients with NHL.

The place of allogeneic stem cell transplantation in aggressive B-cell non-Hodgkin lymphoma in the era of CAR-T-cell therapy

Chimeric antigen receptor T (CAR-T) cells are a treatment option for patients with relapse/refractory (R/R) non-Hodgkin lymphoma (NHL), acute lymphoid leukemia and multiple myeloma. To date, diffuse large B-cell lymphoma (DLBCL), mantle cell lymphoma (MCL), follicular lymphoma (FL), and chronic lymphocytic leukemia (CLL) have been successfully treated with CAR-T cells directed against the CD19 antigen. However, when R/R disease persists after several treatment lines, patients with these diseases are often referred to transplantation centres to receive allogeneic stem cell transplantation (ALLO-SCT). ALLO-SCT and CAR-T cells share mechanism of actions, inducing immune effects of T-cells (and other cells after transplantation) against lymphoma cells, but they differ in several other characteristics. These differences justify unique positioning of each therapy within treatment algorithms. In this paper, we analyzed the results obtained after ALLO-SCT and CAR-T-cell therapy in patients with aggressive lymphomas (large B-cell lymphoma and MCL) to identify the ideal scenarios in which these 2 immunological therapies should be employed.

Multiple CAR-T cell therapy for acute B-cell lymphoblastic leukemia after hematopoietic stem cell transplantation: A case report

B-cell acute lymphoblastic leukemia (B-ALL) is the most common childhood malignancy. The cure rate has reached 90% after conventional chemotherapy and hematopoietic stem cell transplantation (HSCT), but the prognosis of patients with relapsed and refractory (R/R) leukemia is still poor after conventional treatment. Since FDA approved CD19 CAR-T cell (Kymriah) for the treatment of R/R B-ALL, increasing studies have been conducted on CAR-T cells for R/R ALL. Herein, we report the treatment of a patient with ALL who relapsed after allogeneic HSCT, had a complete remission (CR) to murine scFv CD19 CAR-T but relapsed 15 months later. Partial response was achieved after humanized CD19 CAR-T treatment, and the patient finally achieved disease-free survival after sequential CD22 CAR-T treatment. By comparing the treatment results of different CAR-T cells in the same patient, this case suggests that multiple CAR-T therapies are effective and safe in intramedullary and extramedullary recurrence in the same patient, and the expansion of CAR-T cells and the release of inflammatory cytokines are positively correlated with their efficacy. However, further clinical studies with large sample sizes are still needed for further clarification.

Outcomes after allogeneic hematopoietic stem cell transplantation for adults with primary mediastinal B cell lymphoma: a SFGM-TC and LYSA study

Background: Despite therapeutic progress, 10 to 30% of adult patients with primary mediastinal B cell lymphoma (PMBCL) are primary refractory or experience early relapse (R/R). Allogeneic stem cell transplantation (allo-HSCT) thus remains a potentially curative option in this setting.Material and Methods: In this multicenter retrospective study, the outcomes of 33 French and Belgian adult patients allo-transplanted for R/R PMBCL between January 1999 and December 2018, were examined.Results: At allo-HSCT time, patients had received a median of 3 treatment lines, 50% of them were in complete response, 40% in partial response and 10% had a progressive disease. Forty-two percent of the donors were siblings and 39% matched related. The median follow-up for alive patients was 78 months (3.5-157). Considering the whole cohort, 2-year overall survival (OS), progression free survival (PFS) and graft-versus-host disease-free/relapse-free survival (GRFS) were 48% (95%CI: 33-70), 47% (95%CI: 33-68) and 38.5% (95%CI: 25-60) respectively. Cumulative incidence of relapse and non-relapse mortality rates were respectively 34% (95%CI: 18-50) and 18% (95%CI: 7-34). Disease status at transplant was the only factor predicting survivals, patients with progressive disease showing significant lower 2-year PFS (HR: 6.12, 95%CI: 1.32-28.31, p = 0.02) and OS (HR: 7.04, 95%CI: 1.52-32.75, p = 0.013). A plateau was observed for OS and PFS after 4 years with 10 patients alive after this date, suggesting that almost one third of the patients effectively salvaged and undergoing allo-SCT could be cured.Conclusion: This study indicates that allo-HSCT is a valid therapeutic option for R/R PMBCL, providing durable remissions.

Salvage High-dose Melphalan With Autologous Stem cell Transplantation as Bridge to Consolidation Therapy for Chemoresistant Aggressive B-cell Lymphoma

BACKGROUND

Patients suffering from refractory aggressive B-cell lymphoma not responding to salvage chemotherapy have a dismal prognosis. CAR T-cells or allogeneic stem cell transplantation (SCT) are potentially curative approaches. However, obtaining a remission, and lowering tumor burden before consolidation seems crucial for long-term efficacy of both treatment modalities.

MATERIALS AND METHODS

In this retrospective analysis, we reviewed patients with chemoresistant aggressive B-cell lymphoma, defined as being refractory or progressive to at least second line salvage chemotherapy including the regimen immediately preceding autologous stem cell transplantation (ASCT), treated at 2 tertiary centers, who were eligible for intensive treatment using single agent high-dose (HD) melphalan to obtain a remission before consolidating therapy.

RESULTS

We identified 36 patients that received single agent HD melphalan and ASCT as remission induction followed by CAR T-cells or allogeneic stem cell transplantation (SCT). Thirteen of the evaluable patients (39.4%) achieved a partial remission and 9 patients (27.73%) a complete remission, resulting in an overall response rate (ORR) of 66.7%. High remission rates were seen across all subgroups including patients with primary refractory lymphoma (ORR 58.3%), uncontrolled disease and high tumor burden as indicated by increased LDH levels (ORR 66.7% for patients with elevated LDH above 2 times upper limit of norm). 22 patients proceeded to allogeneic SCT and 5 to CAR T-cell therapy. Treatment related mortality of ASCT was 5.5% (2 patients, both due to infections). Two-year overall survival of all patients was 15.8%, primarily due to a high non-relapse mortality (45.5%) of allogeneic SCT patients treated with myeloablative conditioning chemotherapy.

CONCLUSION

Single agent HD melphalan produces high remission rates in patients with chemoresistant, uncontrolled aggressive B-cell lymphoma and provides a window of opportunity for consolidation therapy.

MICROABSTRACT

Patient with refractory/relapsed aggressive B-cell lymphoma after salvage therapy are an unmet medical need because of their very poor prognosis. In our retrospective analysis of 36 patients we showed that single agent high-dose melphalan can achieve high response rates (ORR 66.7%) even in uncontrolled disease enabling consolidation therapy e.g. with allogeneic stem cell transplantation or CAR T-cell therapy.

A calibrated Bayesian method for the stratified proportional hazards model with missing covariates

Missing covariates are commonly encountered when evaluating covariate effects on survival outcomes. Excluding missing data from the analysis may lead to biased parameter estimation and a misleading conclusion. The inverse probability weighting method is widely used to handle missing covariates. However, obtaining asymptotic variance in frequentist inference is complicated because it involves estimating parameters for propensity scores. In this paper, we propose a new approach based on an approximate Bayesian method without using Taylor expansion to handle missing covariates for survival data. We consider a stratified proportional hazards model so that it can be used for the non-proportional hazards structure. Two cases for missing pattern are studied: a single missing pattern and multiple missing patterns. The proposed estimators are shown to be consistent and asymptotically normal, which matches the frequentist asymptotic properties. Simulation studies show that our proposed estimators are asymptotically unbiased and the credible region obtained from posterior distribution is close to the frequentist confidence interval. The algorithm is straightforward and computationally efficient. We apply the proposed method to a stem cell transplantation data set.

Impact of conditioning regimen intensity on the outcomes of peripheral T-cell lymphoma, anaplastic large cell lymphoma and angioimmunoblastic T-cell lymphoma patients undergoing allogeneic transplant

There have been no large studies comparing reduced-intensity/non-myeloablative conditioning (RIC/NMA) to myeloablative conditioning (MAC) regimens in T-cell non-Hodgkin lymphoma (T-NHL) patients undergoing allogeneic transplant (allo-HCT). A total of 803 adults with peripheral T-cell lymphoma, anaplastic large cell lymphoma and angioimmunoblastic T-cell lymphoma (age 18-65 years), undergoing allo-HCT between 2008-2019 and reported to the Center for International Blood and Marrow Transplant Research with either MAC (n = 258) or RIC/NMA regimens (n = 545) were evaluated. There were no significant differences between the two cohorts in terms of patient sex, race and performance scores. Significantly more patients in the RIC/NMA cohort had peripheral blood grafts, haematopoietic cell transplantation-specific comorbidity index (HCT-CI) of ≥3 and chemosensitive disease compared to the MAC cohort. On multivariate analysis, overall survival (OS) was not significantly different in the RIC/NMA cohort compared to the MAC cohort (hazard ratio (HR) = 1.01, 95% confidence interval (CI) = 0.79-1.29; p = 0.95). Similarly, non-relapse mortality (NRM) (HR = 0.85, 95% CI = 0.61-1.19; p = 0.34), risk of progression/relapse (HR = 1.29; 95% CI = 0.98-1.70; p = 0.07) and therapy failure (HR = 1.14; 95% CI = 0.92-1.41, p = 0.23) were not significantly different between the two cohorts. Relative to MAC, RIC/NMA was associated with a significantly lower risk of grade 3-4 acute graft-versus-host disease (HR = 0.67; 95% CI = 0.46-0.99, p = 0.04). Among chemorefractory patients, there was no difference in OS, therapy failure, relapse, or NRM between RIC/NMA and MAC regimens. In conclusion, we found no association between conditioning intensity and outcomes after allo-HCT for T-cell NHL.

Dosimetric Approaches for Radioimmunotherapy of Non-Hodgkin Lymphoma in Myeloablative Setting

Radioimmunotherapy (RIT) is a safe and active treatment available for non-Hodgkin lymphomas (NHLs). In particular, two monoclonal antibodies raised against CD20, that is Zevalin (⁹⁰Y-ibritumomab-tiuxetan) and Bexxar (¹³¹I-tositumomab) received FDA approval for the treatment of relapsing/refractory indolent or transformed NHLs. RIT is likely the most effective and least toxic anticancer agent in NHLs. However, its use in the clinical setting is still debated and, in case of relapse after optimized rituximab-containing regimens, the efficacy of RIT at standard dosage is suboptimal. Thus, clinical trials were based on the hypothesis that the inclusion of RIT in myeloablative conditioning would allow to obtain improved efficacy and toxicity profiles when compared to myeloablative total-body irradiation and/or high-dose chemotherapy regimens. Standard-activity RIT has a safe toxicity profile, and the utility of pretherapeutic dosimetry in this setting can be disputed. In contrast, dose-escalation clinical protocols require the assessment of radiopharmaceutical biodistribution and dosimetry before the therapeutic injection, as dose constrains for critical organs may be exceeded when RIT is administered at high activities. The aim of the present study was to review and discuss the internal dosimetry protocols that were adopted for non-standard RIT administration in the myeloablative setting before hematopoietic stem cell transplantation in patients with NHLs.

Immunotherapy for Diffuse Large B-Cell Lymphoma: Current Landscape and Future Directions

Simple Summary

Immunotherapy has played a pivotal role in the management of relapsed DLBCL. Stem cell transplant and CAR T-cell therapy are curative treatment modalities for relapsed disease. Despite this, a subset of patients continues to progress, and their outcomes remain dismal. Newer therapeutic options to optimize outcomes as well as minimize toxicity are warranted.

Abstract

Diffuse large B-cell lymphoma (DLBCL) is a heterogeneous disease. B-cell receptor (BCR) pathway is essential for malignant B-cell growth, survival, and proliferation. Various immune cells, including T-cells and macrophages in the tumor microenvironment (TME) contribute to tumor cell survival and pathogenesis of chemo-resistance. The presence of many targets on the malignant B-cells and in the TME has led to emergence of novel therapeutic agents. Stem cell transplant is the oldest treatment modality leveraging immune system in DLBCL. Subsequently, CD20 targeting monoclonal antibody and chimeric antigen receptor (CAR) T-cell therapy changed the treatment landscape of DLBCL. Recently, multiple novel immunotherapeutic agents have been added in the armamentarium for the management of DLBCL, and many are under development. In this review article, we will review latest updates of immunotherapeutic agents in the management of DLBCL.

Development of CMV-CD19 bi-specific CAR T cells with post-infusion in vivo boost using an anti-CMV vaccine

Adoptive transfer of in vitro expanded, chimeric antigen receptor (CAR)-redirected CD19-specific T cells can induce dramatic disease regression in patients with leukemia and lymphomas. However, the full potential of this emerging modality is hampered in some cancer settings by a significant rate of therapeutic failure arising from the attenuated engraftment and persistence of CAR-redirected T cells, and tumor relapse following adoptive transfer. Here, we discuss an advanced strategy that facilitates post-infusion in vivo boosting of CAR T cells via CMV vaccination, to mediate durable remission of B cell malignancies by engrafting a CAR molecule onto a CMV-specific T cell. We also discuss a feasible and unique platform for the generation of the CMV-CD19CAR T cells for clinical application. This new approach would overcome multiple challenges in current CAR T cell technology including: short T cell persistence, limited duration of response, and inability to re-stimulate T cells after relapse or persistent disease.

Analysis of real-world data in patients with relapsed/refractory diffuse large B cell lymphoma who received salvage chemotherapy in the rituximab era

Although the overall clinical outcome of patients with diffuse large B cell lymphoma (DLBCL) has significantly improved, some patients still experience relapsed/refractory disease. In the rituximab era, real-world data about relapsed/refractory DLBCL are limited. To clarify the clinical outcome and prognostic factors in these patients, we conducted a retrospective analysis using data from the population-based Osaka Cancer Registry (OCR) from 2010 to 2015. In total, 189 adult patients aged up to 70 years who received CHOP or a CHOP-like regimen in combination with rituximab, as well as a subsequent second-line therapy, were included in the analysis. The median age was 63 years (range, 24-70). Age (> 63 years), the duration of first progression-free survival (PFS), and the use of rituximab in the second-line chemotherapy were prognostic factors for overall survival (OS) after the second-line treatment. In this cohort, 48 and 11 patients received autologous and allogeneic hematopoietic stem cell transplantation (HSCT), respectively. The probabilities of 3-year OS after autologous and allogeneic HSCT were 55.7% and 18.2%, respectively. In conclusion, we found that the clinical outcome of patients with relapsed/refractory DLBCL in the rituximab era was unsatisfactory. Further improvements in treatment strategies, including novel agents, are needed.

A Phase 2 Study of PNT2258 for Treatment of Relapsed or Refractory B-Cell Malignancies

BACKGROUND

PNT2258 consists of a native, chemically unmodified, 24-base DNA oligonucleotide designed to target the regulatory region upstream of the BCL2 gene, delivered in a protective liposome. Derangement of BCL2-regulated control mechanisms is a defining characteristic of certain malignancies, and it was hypothesized that the oligonucleotide would promote anticancer activity via suppression of BCL2 transcription.

METHODS

PNT2258 was evaluated in this, multicenter, nonrandomized, open-label Phase 2 study in 13 participants with relapsed/refractory B-cell malignancies to investigate potential antitumor activity and safety. Participants with follicular lymphoma, diffuse large B-cell lymphoma, mantle cell lymphoma, or chronic lymphocytic leukemia received intravenous PNT2258 120 mg/m² on Days 1 to 5 of a 21-day cycle for up to 8 cycles, followed by 100 mg/m² on Days 1 to 2 of a 28-day cycle until study withdrawal.

RESULTS

All 13 participants were treated with PNT2258 monotherapy and evaluable for response and safety and tolerability. The overall response rate was 53.8% (7/13; 95% confidence interval [CI], 25.1%-80.8%). Median duration of response was 23.4 months (range, 3, 31.5). The disease control rate of participants with stable disease or better was 84.6% (95% CI, 54.6%-98.1%). The most frequently (≥50%) observed adverse events (AEs) were nausea, chills, diarrhea, fatigue, headache, vomiting, and back pain. Hypertension (30.8%) and diarrhea (23.1%) were the most frequent grade ≥3 AEs. No deaths were observed.

CONCLUSION

Clinically meaningful and durable activity with an acceptable safety profile was observed in participants with relapsed/refractory B-cell malignancies who received single-agent PNT2258.

TRIAL REGISTRATION

NCT01733238, first posted 26-Nov-2012. https://clinicaltrials.gov/ct2/show/NCT01733238.

Allogeneic Blood or Marrow Transplantation with Nonmyeloablative Conditioning and High-Dose Cyclophosphamide-Based Graft-versus-Host Disease Prophylaxis for Secondary Central Nervous System Lymphoma

Secondary central nervous system (CNS) lymphoma is a rare and often fatal complication of non-Hodgkin lymphoma (NHL). Treatment options include radiation therapy, high-dose systemic chemotherapy, intrathecal chemotherapy, and high-dose chemotherapy with autologous stem cell rescue, but outcomes remain poor. Allogeneic blood or marrow transplantation (alloBMT) is widely used in patients with relapsed/refractory systemic NHL. We sought to understand whether a graft-versus-lymphoma effect could maintain remission in CNS disease. We reviewed outcomes in 20 consecutive patients with secondary CNS lymphoma who underwent alloBMT with nonmyeloablative conditioning using fludarabine, cyclophosphamide, and 200 cGy total body irradiation. For graft-versus-host disease prophylaxis, all patients received post-transplantation cyclophosphamide, mycophenolate mofetil, and a calcineurin inhibitor. With a median follow up of 4.1 years, the median overall survival for the entire cohort was not reached. Median progression-free survival was 3.8 years (95% confidence interval [CI], 5.3 months to not reached). The cumulative incidence of relapse was 25% (95% CI, 5% to 45%), and nonrelapse mortality was 30% (95% CI, 5% to 54%) at 4 years. Of the 5 patients who relapsed, 2 were CNS only, 1 was systemic only, and 2 were combined CNS/systemic. The use of alloBMT in CNS lymphoma merits further investigation.

Dose intensity for conditioning in allogeneic hematopoietic cell transplantation: can we recommend "when and for whom" in 2021?

Allogeneic hematopoietic stem-cell transplantation is a potentially curative therapy for various hematologic diseases. An essential component of this procedure is the pre-transplant conditioning regimen, which should facilitate engraftment and reduce or eliminate tumor cells. The recognition of the substantial association of a graft-versus- tumor effect and the high toxicity of the commonly used conditioning regimen led to the introduction of more differentiated intensity strategies, with the aim of making hematopoietic stem-cell transplantation less toxic and safer, and thus more applicable to broader populations such as older or unfit patients. In general, prospective and retrospective studies suggest a correlation between increasing intensity and nonrelapse mortality and an inverse correlation with relapse incidence. In this review, we will summarize traditional and updated definitions for conditioning intensity strategies and the landscape of comparative prospective and retrospective studies, which may help to find the balance between the risk of non-relapse mortality and relapse. We will try to underscore the caveats regarding these definitions and analyses, by missing complex differences between intensity and toxicity as well as the broad influences of other factors in the transplantation procedure. We will summarize evidence regarding several confounders which may influence decisions when selecting the intensity of the conditioning regimen for any given patient, according to the individual risk of relapse and non-relapse mortality.

Hematopoietic Stem Cell Transplantation in T Cell and Natural Killer Cell Lymphomas: Update on Recent Advances

Mature T and natural killer (NK) cell non-Hodgkin lymphoma (T-NHL) has a poor prognosis. Data from existing retrospective and prospective studies have suggested that high-dose chemotherapy followed by autologous hematopoietic cell transplantation (auto-HCT) may improve the survival in patients with chemosensitive disease, either in the upfront or salvage setting. Auto-HCT is currently recommended to be used as frontline consolidation in peripheral T cell lymphoma not otherwise specified, angioimmunoblastic T cell lymphoma, anaplastic large cell lymphoma-anaplastic lymphoma kinase negative, NK/T cell (disseminated), and enteropathy-associated T cell lymphoma. However, about one-third of patients never reach transplantation because of early relapse or refractory disease. Allogeneic hematopoietic cell transplantation (allo-HCT), via its immunologic graft-versus-lymphoma effect, has been used to salvage patients with relapsed or refractory disease, resulting in long-term disease-free survival in a fraction of patients. However, the higher risk of transplant-related mortality due to regimen-related toxicities, graft-versus-host disease, and post-transplant infectious complications continues to limit the mainstream adoption of allo-HCT for this disease. Despite that, allo-HCT has been incorporated as part of the frontline treatment for aggressive subtypes of T-NHL, such as γδ T cell lymphoma and aggressive NK cell leukemia. Recent attempts to incorporate novel targeted T cell directed therapies into the treatment pathway of T-NHL may enhance treatment response and enable more patients to reach transplant, offering an alternative means of treating this disease.

Allogeneic stem cell transplantation as a curative option in relapse/refractory diffuse large B cell lymphoma: Spanish multicenter GETH/GELTAMO study

We performed a retrospective multicenter study including 140 patients with relapsed/refractory (R/R) diffuse large B cell lymphoma (DLBCL) who underwent allogeneic hematopoietic stem cell transplantation (allo-SCT) from March 1995 to November 2018. Our objective was to analyze long term outcomes. Seventy-four percent had received a previous auto-SCT (ASCT) and the median number of lines pre-allo-SCT was 3 (range 1-9). Three year-event free survival (EFS) and overall survival (OS) were 38% and 44%, respectively. Non-relapse mortality (NRM) at day 100 was 19%. Cumulative incidence of grade III-IV acute graft versus host disease (GVHD) at day 100 was 16% and moderate/severe chronic GVHD at 3 years 34%. Active disease at allo-SCT (HR 1.95, p = 0.039) (HR 2.19, p = 0.019), HCT-CI ≥ 2 (2.45, p = 0.002) (HR 2.33, p = 0.006) and donor age >37 years (HR 2.75, p = 0.014) (HR 1.98, p = 0.043) were the only independent variables both for PFS and OS, respectively. NRM was significantly modified by HCT-CI ≥ 2 (HR 4.8, p = 0.008), previous ASCT (HR 4.4, p = 0.048) and grade III-IV acute GVHD on day 100 (HR 6.13, p = 0.016). Our data confirmed that allo-SCT is a curative option for patients with R/R DLBCL, displaying adequate results for fit patients with chemosensitive disease receiving an allo-SCT from a young donor.

Single agent oral selinexor as a key to potential cure in refractory diffuse large B-cell lymphoma: case report and literature review

Relapsed/refractory diffuse large B-cell lymphoma (DLBCL) portends a poor prognosis, with an estimated overall survival of less than 6 months. In the presented case, a female patient with DLBCL refractory to multiple lines of therapy, including chimeric antigen receptor T-cells, was treated with single-agent selinexor, achieving partial response following 5 months of treatment, which allowed the patient to proceed to potentially curative allogeneic stem cell transplantion. This approach enabled the patient, who would otherwise have been considered a candidate for palliative care, to achieve the most prolonged complete response since her first lymphoma-specific treatment. This outcome implies that early identification of relapsed/refractory patients who may benefit most from this drug - either as a single agent or in drug combinations - is imperative.

Sequential intensive chemotherapy followed by autologous or allogeneic transplantation for refractory lymphoma

We evaluate the safety of bendamustine as a bridge to stem cell transplantation (SCT) in patients with relapsed/refractory lymphoma and residual disease after salvage therapy. Thirty-four subjects without complete responses (CR) received bendamustine 200 mg/m²/day for 2 days followed 14 days later by SCT. Sixteen subjects in partial remission (PR) with maximal FDG-PET SUVs ≤8 prior to bendamustine received autologous SCT, while 13 with suboptimal responses were allografted. Five subjects did not proceed to transplant. No bendamustine toxicities precluded transplantation and no detrimental effect on engraftment or early treatment-related mortality (TRM) was attributable to bendamustine. At 1 year, 75% of auto-recipients and 31% of allo-recipients were alive with CR. Two subjects in the autologous arm developed therapy-related myeloid neoplasia (t-MN). In conclusion, a bendamustine bridge to SCT can be administered without early toxicity to patients with suboptimal responses to salvage chemotherapy. However this approach may increase the risk of t-MN. (NCT02059239).Supplemental data for this article is available online at here.

Association of Reduced-Intensity Conditioning Regimens With Overall Survival Among Patients With Non-Hodgkin Lymphoma Undergoing Allogeneic Transplant

Importance

Reduced-intensity conditioning and nonmyeloablative conditioning (RIC-NMAC) regimens are frequently used in allogeneic hematopoietic cell transplant (HCT) for non-Hodgkin lymphoma. However, the optimal RIC-NMAC regimen in allogeneic HCT for non-Hodgkin lymphoma is not known.

Objective

To investigate whether RIC-NMAC regimens at a higher end of the intensity spectrum are associated with increased nonrelapse mortality and lower overall survival compared with RIC-NMAC regimens at the lower end of the intensity spectrum in patients with non-Hodgkin lymphoma undergoing allogeneic HCT.

Design, Setting, and Participants

This cohort study used data from 1823 adult patients with non-Hodgkin lymphoma in the Center for International Blood and Marrow Transplant Research registry. Included patients underwent allogeneic HCT using matched related or unrelated donors between January 2008 and December 2016. Statistical analysis was performed from June 1, 2019, to February 10, 2020.

Interventions

Patients received 1 of 4 RIC-NMAC regimens: fludarabine-intravenous busulfan (Flu-Bu), approximately 6.4 mg/kg (n = 458); fludarabine-melphalan (Flu-Mel140), 140 mg/m2 (n = 885); fludarabine-cyclophosphamide (Flu-Cy) (n = 391); or Flu-Cy with 2 Gy total body irradiation (Flu-Cy-2GyTBI) (n = 89).

Main Outcomes and Measures

The primary outcome was overall survival. Secondary outcomes were nonrelapse mortality, incidence of relapse, progression-free survival, and the incidence of acute and chronic graft-vs-host disease (GVHD).

Results

Of 1823 patients, 1186 (65%) were male, with a mean (SD) age of 54.8 (9.9) years. The 4-year adjusted OS was 58% in the Flu-Bu cohort, 67% in the Flu-Cy-2GyTBI cohort, 49% in the Flu-Mel140 cohort, and 63% in the Flu-Cy cohort (P < .001). After adjustment for age, Karnofsky performance score, HCT comorbidity index, NHL subtype, remission status at HCT, and the use of antithymocyte globulin or alemtuzumab, the regression analysis showed a significantly higher mortality risk associated with Flu-Mel140 compared with Flu-Bu (hazard ratio [HR], 1.34; 95% CI, 1.13-1.59; P < .001). Compared with the Flu-Cy cohort, the Flu-Mel140 cohort had a higher risk of chronic GVHD (HR, 1.38; 95% CI, 1.15-1.65; P < .001). The Flu-Mel140 regimen was associated with a higher nonrelapse mortality risk (HR, 1.78; 95% CI, 1.37-2.31; P < .001) compared with the Flu-Bu regimen.

Conclusions and Relevance

The findings suggest that use of the more intense RIC-NMAC regimen, Flu-Mel140, may have a negative association with overall survival and may be associated with higher nonrelapse mortality. The Flu-Bu and Flu-Cy regimens with or without 2GyTBI regimens appeared to provide comparable overall survival.

Hematopoeitic Cell Transplantation and CAR T-Cell Therapy: Complements or Competitors?

Allogeneic hematopoietic cell transplantation (allo-HCT) and chimeric antigen receptor T cell (CAR T) therapy are the main modalities of adoptive cellular immunotherapy that have widely permeated the clinical space. The advent of both technologies revolutionized treatment of many hematologic malignancies, both offering the chance at sustained remissions for patients who would otherwise invariably succumb to their diseases. The understanding and exploitation of the nonspecific alloreactivity of allo-HCT and the graft-versus-tumor effect is contrasted by the genetically engineered precision of CAR T therapy. Historically, those with relapsed and refractory hematologic malignancies have often been considered for allo-HCT, although outcomes vary dramatically and are associated with potential acute and chronic toxicities. Such patients, mainly with B-lymphoid malignancies, may now be offered CAR T therapy. Yet, a lack of prospective data to guide decisions thereafter requires individualized approaches on whether to proceed to allo-HCT or observe. The continued innovations to make CAR T therapy more effective and accessible will continue to alter such approaches, but similar innovations in allo-HCT will likely result in similarly improved clinical outcomes. In this review, we describe the history of the two platforms, dissect the clinical indications emphasizing their intertwining and competitive roles described in trials and practice guidelines, and highlight innovations in which they complement or inform one another.

Immunotherapy with cells

Both older and newer cell therapies have demonstrated impressive responses in otherwise poor-prognosis lymphomas. Consequently, cellular therapy now plays a major role in the management of many non-Hodgkin lymphomas. In this article, we examine the role of chimeric antigen receptor (CAR) T cells, allogeneic stem cell transplantation, and virus-directed T cells for treatment of lymphomas. We review the current indications for CAR T cells and discuss our clinical approach to selecting and treating patients with aggressive B-cell lymphomas to receive CD19-directed CAR T cells. In addition, we highlight newer cell therapies and provide an overview of promising future approaches that have the potential to transform immunotherapy with cells to treat lymphomas.

Haploidentical Stem Cell Transplantation in Lymphomas-Expectations and Pitfalls

T-cell replete Haploidentical stem cell transplantation (Haplo-SCT) with Post-transplant cyclophosphamide (PT-Cy) is an emerging therapeutic option for patients with advanced relapsed or refractory lymphoma. The feasibility of this platform is supported by several retrospective studies showing a toxicity profile that is improved relative to umbilical cord blood and mismatched unrelated donor (UD) transplant and comparable to matched unrelated donor transplant. In particular, cumulative incidence of chronic graft-versus-host disease (GVHD) is reduced after Haplo-SCT relative to UD and matched related donor (MRD) transplant thanks to PT-Cy employed as GVHD prophylaxis. This achievement, together with a similar incidence of acute GVHD and disease relapse, results in a promising advantage of Haplo-SCT in terms of relapse-free/GVHD free survival. Unmet needs of the Haplo-SCT platform are represented by the persistence of a not negligible rate of non-relapse mortality, especially due to infections and disease relapse. Future efforts are warranted in order to reduce life-threatening infections and to employ Halo-SCT with PT-Cy as a platform to build new immunotherapeutic strategies.

Impact of Reduced-Intensity Conditioning Regimens on Outcomes in Diffuse Large B Cell Lymphoma Undergoing Allogeneic Transplantation

Reduced-intensity conditioning (RIC) regimens are frequently used for allogeneic hematopoietic cell transplantation (allo-HCT) in patients with diffuse large B cell lymphoma (DLBCL). However, the RIC regimen with the best risk/benefit profile for allo-HCT in DLBCL is not known. This is particularly important because patients with DLBCL undergoing allo-HCT in the future would be enriched for those whose lymphoma has failed chimeric antigen receptor T cell (CAR-T) therapy or other novel immunotherapies, with potentially more advanced disease and suboptimal performance scores. Using the Center for International Blood and Marrow Transplant Research (CIBMTR) database, we report the outcomes of the 3 most commonly used allo-HCT RIC regimens in patients with DLBCL. Our analysis included a total of 562 adult DLBCL patients in the CIBMTR registry undergoing allo-HCT using matched related or unrelated donors, between 2008 and 2016. Patients received 1 of 3 RIC regimens: fludarabine/i.v. busulfan ~6.4 mg/kg (Flu/Bu), fludarabine/melphalan 140 mg/m² (Flu/Mel140), or BCNU/etoposide/cytarabine/melphalan (BEAM). Accordingly, the study group was divided into 3 groups: Flu/Bu (n = 151), Flu/Mel140 (n = 296), and BEAM (n = 115). Relative to Flu/Bu, the Flu/Mel140 (hazard ratio [HR], 2.33; 95% confidence interval [CI], 1.42 to 3.82; P = .001) and BEAM (HR, 2.54; 95% CI, 1.34 to 4.80; P = .004) regimens were associated with a risk of higher nonrelapse mortality (NRM). Although the risk of relapse with Flu/Mel140 was lower than that with Flu/Bu (HR, .70; 95% CI, .52 to .95; P = .02), this did not translate to improved progression-free survival (HR, 1.04) or overall survival (HR, 1.30). There was a significantly higher risk of grade III-IV acute graft-versus-host disease with BEAM compared with Flu/Bu (HR, 2.19; 95% CI, 1.10 to 4.35; P = .03). In the chemosensitive subset, multivariate analysis showed a significantly higher mortality risk with Flu/Mel140 (HR, 1.48; 95% CI, 1.07 to 2.04; P = .02) relative to Flu/Bu conditioning. In the largest analysis comparing the impact of various RIC regimens on the survival of DLBCL patients undergoing allo-HCT, our results suggest that Flu/Bu is a better RIC choice in less fit or heavily pretreated patients due to lowest NRM risk.

Cellular Immunotherapy for Refractory Diffuse Large B Cell Lymphoma in the Chimeric Antigen Receptor-Engineered T Cell Era: Still a Role for Allogeneic Transplantation?

Chimeric antigen receptor-engineered T (CART) cells are a promising new treatment option for patients with multiply relapsed and refractory (R/R) diffuse large B cell lymphoma (DLBCL). Because of the favorable outcome data reported for CART cells, uncertainty is emerging if there is still a role for allogeneic hematopoietic cell transplantation (allo-HCT) in the treatment of R/R DLBCL. This article provides an overview of available evidence and theoretical considerations to put these 2 types of cellular immunotherapy (CI) into perspective. Altogether, current data suggest that CART cells are preferred now over transplantation as first-choice CI in many clinical situations. However, the majority of patients will fail CART therapy, resulting in an unmet medical need where allo-HCT could be beneficial. In contrast, employing allo-HCT instead of CART cells as first CI should be presently restricted to situations where CART cell therapy is deemed not feasible or useful, such as patients with refractory cytopenia or incipient myelodysplastic syndrome. However, allo-HCT remains a standard treatment option as first CI for patients with chemosensitive R/R DLBCL when CARTs are not available or transplantation is preferred by the patient. Continuous collection and analysis of CI outcome data by professional registries appear to be of key importance for developing rational strategies of CI allocation and sequencing.

PTCy-based haploidentical vs matched related or unrelated donor reduced-intensity conditioning transplant for DLBCL

This study retrospectively compared long-term outcomes of nonmyeloablative/reduced intensity conditioning (NMC/RIC) allogeneic hematopoietic cell transplantation (allo-HCT) from a haploidentical family donor (haplo-HCT) using posttransplant cyclophosphamide (PTCy) with those of matched sibling donor (MSD) and matched unrelated donor (MUD) with or without T-cell depletion (TCD+/TCD-) in patients with relapsed diffuse large B-cell lymphoma (DLBCL). Adult patients with DLBCL who had undergone their first NMC/RIC allo-HCT between 2008 and 2015 were included. Recipients of haplo-HCT were limited to those receiving graft-versus-host disease (GVHD) prophylaxis with PTCy. GVHD prophylaxis in MSD was limited to calcineurin inhibitor (CNI)-based approaches without in vivo TCD, while MUD recipients received CNI-based prophylaxis with or without TCD. Outcome analyses for overall survival (OS) and progression-free survival (PFS), nonrelapse mortality (NRM), and disease relapse/progression were calculated. A total of 1438 patients (haplo, 132; MSD, 525; MUD TCD+, 403; and MUD TCD-, 378) were included. Patients with haplo donors were significantly older, had a better performance status and had more frequently received total body irradiation-based conditioning regimens and bone marrow grafts than MSD and MUD TCD+ or TCD-. 3-year OS, PFS, NRM and relapse/progression incidence after haplo-HCT was 46%, 38%, 22%, and 41%, respectively, and not significantly different from outcomes of matched donor transplants on multivariate analyses. Haplo-HCT was associated with a lower cumulative incidence of chronic GVHD compared with MSD, MUD TCD+/TCD-. NMC/RIC haplo-HCT with PTCy seems to be a valuable alternative for patients with DLBCL considered for allo-HCT but lacking a matched donor.

Haploidentical Stem Cell Transplantation With Posttransplant Cyclophosphamide Therapy vs Other Donor Transplantations in Adults With Hematologic Cancers: A Systematic Review and Meta-analysis

Importance

Use of haploidentical (HAPLO) stem cell transplantation with posttransplant cyclophosphamide is rapidly increasing in adults with hematologic cancers. However, its specific role compared with other transplant strategies has yet to be identified.

Objective

To synthesize the existing evidence regarding outcomes of stem cell transplantations comparing HAPLO stem cell transplantation and posttransplant cyclophosphamide therapy with transplantations from matched related donors (MRDs), matched unrelated donors (MUDs), or mismatched unrelated donors (MMUDs).

Data Sources

PubMed, Cochrane Library, ClinicalTrials.gov, and meeting abstracts were searched for the key words haploidentical and cyclophosphamide from inception through March 1, 2019.

Study Selection

Studies comparing HAPLO stem cell transplantation and posttransplant cyclophosphamide therapy with transplantations from other donors in adults with hematologic cancers were eligible for meta-analysis.

Data Extraction and Synthesis

Pooled odds ratios (ORs) and 95% CIs were calculated using a random-effects model.

Main Outcomes and Measures

Main outcomes were all-cause mortality, nonrelapse mortality, and relapse.

Results

A total of 30 studies including 22 974 participants were analyzed. HAPLO stem cell transplantation with posttransplant cyclophosphamide therapy was associated with increased all-cause mortality compared with MRDs (OR, 1.17; 95% CI, 1.05-1.30), similar all-cause mortality compared with MUDs (OR, 1.06; 95% CI, 0.96-1.18), and reduced all-cause mortality compared with MMUDs (OR, 0.75; 95% CI, 0.61-0.92). Regarding nonrelapse mortality, HAPLO stem cell transplantation with posttransplant cyclophosphamide was associated with worse outcomes compared with MRDs (OR, 1.20; 95% CI, 1.04-1.40) but better outcomes compared with MUDs (OR, 0.75; 95% CI, 0.61-0.92) and MMUDs (OR, 0.51; 95% CI, 0.25-1.02). In terms of relapse, HAPLO stem cell transplantation with posttransplant cyclophosphamide was associated with similar outcome compared with MRDs (OR, 1.01; 95% CI, 0.86-1.17) and MMUDs (OR, 1.06; 95% CI, 0.77-1.47) but showed increased relapse compared with MUDs (OR, 1.20; 95% CI, 1.03-1.40).

Conclusions and Relevance

Results of this meta-analysis suggest that MRDs, if available, remain the optimal donors regarding mortality and HAPLO stem cell transplantation with posttransplant cyclophosphamide may be preferred over MMUDs. Prospective comparisons with MUDs are needed.

Outcomes of allogeneic stem cell transplantation for DLBCL: a multi-center study from the Kyoto Stem Cell Transplantation Group

Allogeneic hematopoietic stem cell transplantation (allo-SCT) has been considered as a potentially curative treatment option for refractory or relapsed diffuse large B cell lymphoma (DLBCL) patients. However, there is little information available, especially for Japanese patients and in cord blood transplantation (CBT). We aimed to determine treatment outcomes of allo-SCT for DLBCL in the Kyoto Stem Cell Transplantation Group, a multi-institutional joint research group. Sixty-eight DLBCL patients who underwent their first allo-SCT between 2003 and 2016 were included. The median time from diagnosis to transplantation was 13.5 months. Thirty-one patients were in CR/PR at transplantation. Twenty-seven patients underwent CBT. The median follow-up for survivors was 44.2 months. Four-year overall survival (OS) and relapse-free survival (RFS) rates were 23% (95% CI, 13-35%) and 20% (95% CI, 11-31%), respectively. Cumulative incidences of non-relapse mortality and relapse were 23% and 57%, respectively. Patients in CR/PR at allo-SCT had better OS (4-year, 46% vs 4%, P < 0.001) and RFS (4-year, 36% vs 7%, P = 0.005). The source of the stem cell did not significantly affect OS (4-year, bone marrow vs cord blood vs peripheral blood, 28.6% vs 27.2% vs 6.5%, P = 0.193). In multivariate analysis, non-remission status at SCT associated with inferior OS and RFS. Duration from diagnosis to transplantation of less than 1 year associated with inferior RFS. Allo-SCT, including CBT, may be a promising therapeutic modality for DLBCL patients who have good disease control at transplantation.

R-BEAM versus Reduced-Intensity Conditioning Regimens in Patients Undergoing Allogeneic Stem Cell Transplantation for Relapsed Refractory Diffuse Large B Cell Lymphoma

Allogeneic stem cell transplant (alloSCT) is considered in diffuse large B cell lymphoma (DLBCL) patients with chemorefractory disease or who have relapsed after autologous SCT. Here we present the first report of alloSCT using the R-BEAM (rituximab, carmustine, etoposide, cytarabine, melphalan) conditioning regimen in DLBCL patients. We retrospectively compared long-term alloSCT outcomes of DLBCL patients who received either R-BEAM (n = 47) or reduced-intensity conditioning (RIC) regimens (n = 23). Seventy patients (median age, 53 years) with DLBCL received alloSCT between January 2005 and December 2017. The median number of pretransplant therapies was 3, and 17 patients (24%) received prior autologous SCT. All received rituximab as a frontline or salvage therapy before alloSCT. The donor was unrelated in 42 patients (60%), and peripheral blood stem cells were commonly used (96%). The 6-month cumulative incidence of grades III to IV acute graft-versus-host disease (GVHD) was 36.2% and 8.7% for R-BEAM and RIC, respectively (P = .03). Median follow-up of surviving patients after R-BEAM and RIC was 3.1 and 5.5 years, respectively. Three-year overall survival (OS) after R-BEAM and RIC was 34.4% and 43.4%, respectively (P = .48). At 3 years, R-BEAM was associated with a similar relapse rate (25.5% versus 26.1%, P = .96), nonrelapse mortality (NRM; 39.7% versus 39.1%, P = .98), and relapse-free survival (RFS; 34.8% versus 34.7%, P = .75) compared with RIC. In multivariable analysis lower Karnofsky performance score was associated with lower OS (hazard ratio, .96; P = .05), whereas chemorefractory disease was associated with a higher relapse risk (hazard ratio, 8.8; P = .04). No difference in OS, relapse, NRM, or RFS was noticed between R-BEAM and RIC. R-BEAM regimen seems to be feasible and results in equivalent rates of long-term OS, relapse, NRM, and RFS compared with RIC. However, a significantly higher rate of severe acute GVHD was noticed.

Clinical outcomes for ibrutinib in relapsed or refractory mantle cell lymphoma in real-world experience

Ibrutinib is highly effective in patients with relapsed or refractory mantle cell lymphoma (MCL) in major clinical trials. Although there has been a dramatic improvement in survival outcomes in the salvage setting, nonresponders to ibrutinib have a bleak prognosis. Therefore, this retrospective study was conducted to identify the most appropriate therapeutic strategy and prognosis‐related factors to predict the response of patients with relapsed or refractory MCL to ibrutinib monotherapy. Thirty‐three consecutive refractory or relapsed MCL patients treated with ibrutinib were analyzed in this study. The median overall survival (OS) and progression‐free survival (PFS) after initiation of ibrutinib were 35.1 months and 27.4 months, respectively. Risk factor analysis showed that high risk according to the Mantle Cell Lymphoma International Prognostic Index (MIPI) and nonresponse to ibrutinib at the first three cycles were significantly associated with inferior OS. Poor PFS was associated with high‐risk biologic MIPI, prior bendamustine exposure, and nonresponse to ibrutinib during the first three cycles. After ibrutinib failure, primary nonresponders had poorer OS and PFS than inconsistent responders. The overall response rate for the first salvage therapy was only 33%, with a median TTP of 3.2 months. There was no effective therapeutic strategy except for allogeneic hematopoietic stem cell transplantation (allo‐HSCT). Although ibrutinib responders exhibited favorable survival outcomes, nonresponders had a dismal prognosis. To overcome these limitations, it may be necessary to modify therapeutic strategies, such as selecting inconsistent responders for earlier allo‐HSCT.

Allogeneic Stem Cell Transplantation Provides Durable Remission in Patients with Primary Mediastinal Large B Cell Lymphoma

Standard therapy for relapsed or refractory (rel/ref) primary mediastinal large B cell lymphoma (PMBCL) is salvage therapy followed by autologous (auto) hematopoietic stem cell transplantation (HSCT). However, many patients have refractory disease and are unable to undergo autoHSCT, and a sizeable proportion of patients will relapse after autoHSCT. By analogy to diffuse large B cell lymphoma, these patients may be treated with allogeneic (allo) HSCT with curative intent, but at the risk of significant morbidity and mortality. Given the advent of effective immunotherapy approaches for rel/ref PMBCL, it is important to better understand the toxicity and efficacy of alloHSCT in these patients, to which these new approaches could be an alternative. Therefore, we retrospectively studied the outcomes of alloHSCT in a multicenter cohort of 28 patients with rel/ref PMBCL who underwent transplantation at 4 centers. Most patients (79%) were sensitive to pretransplantation therapy and 86% received reduced-intensity conditioning. The overall progression-free survival (PFS), overall survival (OS), and cumulative incidences of nonrelapse mortality and relapse in the cohort at 5 years were 34%, 45%, 32%, and 33%, respectively. Outcomes were significantly better in patients with pretransplantation responsive disease (2-year PFS and OS of 50% and 58%, respectively) compared with refractory patients (2-year PFS and OS of 0%). In our multicenter retrospective study, alloHSCT produced durable remissions in a proportion of patients with treatment-sensitive disease before transplantation (5-year PFS of 44%) and should be considered in the treatment of patients with rel/ref PMBCL.

Hematopoietic-cell transplantation for lymphoma in the era of genetically engineered cellular therapy: it's not quite time to scrap the old vehicle for the new car

PURPOSE OF REVIEW

Second-line platinum-based salvage chemotherapy followed by high-dose chemotherapy and autologous hematopoietic-cell transplantation (AHCT) has remained the standard of care (SOC) for relapsed and primary refractory (r/r) diffuse large B-cell lymphoma (DLBCL) for greater than 2 decades. In the postrituximab era, this strategy has yielded disappointing outcomes for r/r patients with curability in less one-quarter of the patients by intention-to-treat.

RECENT FINDINGS

Given the Food and Drug Administration (FDA) approval of chimeric antigen receptor (CAR) modified T cells directed against CD19 (CD19 CAR T) for DLBCL following two lines of therapy and/or failed AHCT, encouragement with this therapy in the second line for r/r patients has naturally prompted randomized phase III studies against the aforementioned SOC. The predominant hurdle to procession to AHCT is chemotherapy sensitivity after platinum-based salvage therapy.

SUMMARY

In this review, we will discuss recent investigations to improve response rates in r/r DLBCL with the intent of proceeding to potentially curative AHCT, as well as investigations to decrease progression post-AHCT. In addition, data regarding currently FDA approved CD19 CAR T cells will be reviewed. Within 2-3 years, we will know if the multicenter/multinational studies of CD19 CAR T will replace SOC salvage therapy and AHCT in the second-line. The role of allogeneic HCT will also be briefly reviewed in the context of these therapies.

Is It Time to Revisit the Role of Allogeneic Transplantation in Lymphoma?

PURPOSE OF REVIEW

A multitude of new drug and cell therapy approvals for lymphoma has prompted questions about the role of allogeneic blood or marrow transplantation (allo-BMT). We sought to review the latest evidence examining the role of allo-BMT for lymphoma in this evolving landscape.

RECENT FINDINGS

Despite several new drug classes, there remains a large unmet need, particularly in hard to treat subtypes of lymphoma and for patients with relapsed/refractory disease. Allo-BMT can provide an opportunity for cure due to a potent graft vs lymphoma effect in high-risk relapse/refractory follicular lymphoma, mantle cell lymphoma, and aggressive T cell lymphomas. Chimeric antigen receptor T cell therapy and checkpoint blockers have improved outcomes for patients with relapsed /aggressive B cell lymphomas and Hodgkin lymphoma respectively; the role of allo-BMT consolidation in the treatment algorithm for responders to these therapies is an evolving topic. Expanded donor availability including haploidentical relatives has improved access to allo-BMT. Non-myeloablative conditioning regimens and post-transplant cyclophosphamide prophylaxis have improved early transplant-related morbidity and rates of graft versus host disease and translated into long-term survival for patients with lymphoid malignancies. Patient selection remains key, but allo-BMT remains the only modality able to deliver durable long-term remissions across different types of lymphoma.

Allogeneic Stem Cell Transplantation and Chimeric Antigen Receptor (CAR) T-Cell Therapy for the Treatment of Non-Hodgkin Lymphoma

Despite the myriad of available treatments, a substantial subset of patients with non-Hodgkin lymphoma are not able to achieve a prolonged disease-free interval with conventional chemotherapy or targeted agents. For these patients, hematopoietic stem cell transplantation remains an option for consolidative or curative treatment. Additionally, chimeric antigen receptor T-cell therapy has emerged for patients with relapsed/refractory B-cell lymphomas. Published studies vary widely in their selected approach to transplant and cellular therapies. This review summarizes available data related to allogeneic hematopoietic stem cell transplantation and chimeric antigen receptor T-cell therapy for the treatment of non-Hodgkin lymphomas.