Minimal Residual Disease Status in Multiple Myeloma 1 Year After Autologous Hematopoietic Cell Transplantation and Lenalidomide Maintenance Are Associated With Long-Term Overall Survival

PURPOSE

Prognostic Immunophenotyping in Myeloma Response (PRIMeR) is an ancillary study of minimal residual disease (MRD) assessment for multiple myeloma by next-generation multiparameter flow cytometry (MFC). Patients were enrolled on a three-arm randomized control trial (Blood and Marrow Transplants Clinical Trials Network 0702 Stem Cell Transplant for Myeloma in Combination of Novel Agents [STaMINA]; ClinicalTrials.gov identifier: NCT01109004).

METHODS

Four hundred and thirty-five patients consented to the MRD panel, which included 10 monoclonal antibodies measured via six-color MFC. MRD was measured at baseline/preautologous hematopoietic cell transplant (BL/preAutoHCT), premaintenance (PM), and 1 year (Y1) after AutoHCT with a sensitivity of 10-5 to 10-6. The primary objective was to assess MRD-negative (MRDneg) at 1 year after AutoHCT and progression-free survival and overall survival (PFS/OS).

RESULTS

Similar to the STaMINA results, at a median follow-up of 70 months, there was no significant difference in PFS/OS by treatment arm in the PRIMeR patients. MRDneg at all three time points was associated with significantly improved PFS, and MRDneg at Y1 had significantly longer OS. Multivariate analysis of PFS, adjusting for disease risk and treatment arm, demonstrated hazard ratios (HRs) in MRD-positive patients compared with MRDneg patients at BL, PM, and Y1 of 1.55 (P = .0074), 1.83 (P = .0007), and 3.61 (P < .0001), respectively. Corresponding HRs for OS were 1.19 (P = .48), 0.88 (P = .68), and 3.36 (P < .001). Patients with sustained MRDneg or who converted to MRDneg by Y1 had similar PFS/OS.

CONCLUSION

To our knowledge, this first, prospective US cooperative group, multicenter study demonstrates that MRDneg at Y1 after AutoHCT with lenalidomide maintenance is prognostic for improved 6-year PFS and OS. Serial MRD measurements may direct trials to test how further therapy may improve long-term PFS and OS.

Benefit of axicabtagene ciloleucel versus chemoimmunotherapy in older patients and/or patients with poor ECOG performance status with relapsed or refractory large B-cell lymphoma after 2 or more lines of prior therapy

Axicabtagene ciloleucel (axi-cel) in trials has demonstrated favorable efficacy compared with historical controls after ≥2 lines of therapy for the treatment of relapsed or refractory (R/R) large B cell lymphoma (LBCL). Herein, we compared the real-world effectiveness of axi-cel with efficacy and effectiveness of chemoimmunotherapy (CIT) in patients aged ≥65 years and patients with Eastern Cooperative Oncology Group performance status (ECOG PS) of 2. A total of 1146 patients treated with commercial axi-cel for R/R LBCL with ≥2 lines of prior therapy were included from the Center for International Blood and Marrow Transplantation Research prospective observational study, and 469 patients treated with CIT for R/R LBCL after ≥2 lines of prior therapy were included from SCHOLAR-1 (an international, multicohort, retrospective study). After propensity score matching, at a median follow-up of 24 months for patients receiving axi-cel and 60 months for patients receiving CIT, 12-month overall survival rates were 62% and 28%, respectively (hazard ratio, 0.30 [95% CI, 0.24-0.37]). Objective response rate (ORR) was 76% (complete response [CR] rate 58%) in patients receiving axi-cel versus 28% (CR rate 16%) for those receiving CIT. A 57% difference in ORR (55% difference in CR rate) favoring axi-cel over CIT was observed among patients aged ≥65 years. Increased magnitude of benefit in response rates for axi-cel versus CIT was also observed among patients with ECOG PS = 2. These findings further support the broader use of axi-cel in older patients and patients with ECOG PS = 2 with R/R LBCL.

Don't keep me waiting: estimating the lifetime impact of reduced vein-to-vein time for CAR-T treated patients with LBCL

Chimeric antigen receptor (CAR) T-cell therapies have revolutionized the treatment of hematological cancers. Production requires a complex logistical process from leukapheresis to patient infusion, the vein-to-vein time (V2VT), during which a patients clinical condition may deteriorate. This study was designed to estimate the benefits of reduced V2VT for third-line+ (3L+) relapsed/refractory large B-cell lymphoma (r/r LBCL) patients treated with CAR T. A mathematical model was developed to estimate the lifetime outcomes of a hypothetical cohort of patients who had either a 'long' or 'short' V2VT. Life-years (LYs), quality-adjusted life years (QALYs), and costs were estimated. Scenario analyses were performed to assess the robustness of results to key assumptions.  The results of the model show that reducing V2VT from 54 days (tisa-cel median V2VT; JULIET) to 24 days (axi-cel median V2VT; ZUMA-1) led to a 3.2-year gain in life expectancy (4.2 vs 7.7 LYs), and 2.4 additional QALYs (3.2 vs 5.6) per patient. Furthermore, a shorter V2VT was shown to be cost-effective under conventional willingness-to-pay thresholds in the United States. Results are driven by a higher infusion rate and and a better efficacy of CAR T-cell therapy for those infused. Scenario analyses using a smaller difference in V2VT (24 vs 36 days) produced consistent results. Our study is the first to quantify lifetime V2VT-related outcomes for 3L+ r/r LBCL patients treated with CAR T utilizing currently available evidence. Shorter V2VTs led to improved outcomes, demonstrating the importance of timely infusion achievable by faster manufacturing times and optimization of hospital delivery.

Real-World and Clinical Trial Outcomes in Large B-cell Lymphoma with Axicabtagene Ciloleucel Across Race and Ethnicity

Axicabtagene ciloleucel (axi-cel) is an autologous anti-CD19 chimeric antigen receptor (CAR) T-cell therapy approved for treatment of relapsed/refractory (R/R) large B-cell lymphoma (LBCL). Despite extensive data supporting the use of axi-cel in patients with LBCL, outcomes stratified by race and ethnicity groups are limited. Here, we report clinical outcomes with axi-cel in patients with R/R LBCL by race and ethnicity in both real-world and clinical trial settings. In the real-world setting, 1290 patients with R/R LBCL who received axi-cel between 2017-2020 were identified from the Center for International Blood and Marrow Transplant Research database; 106 and 169 patients were included from the ZUMA-1 and ZUMA-7 clinical trials, respectively. Adjusted odds ratio (OR) and hazard ratio (HR) for race and ethnicity groups are reported. Overall survival was consistent across race/ethnicity groups. However, non-Hispanic (NH) Black patients had lower overall response rate (OR, 0.37, [95% CI, 0.22-0.63]) and lower complete response rate (OR, 0.57, [95% CI, 0.33-0.97]) than NH-white patients. NH-Black patients also had a shorter progression-free survival versus NH-white (HR, 1.41, [95% CI, 1.04-1.90]) and NH-Asian patients (HR, 1.67, [95% CI, 1.08-2.59]). NH-Asian patients had a longer duration of response compared with NH-white (HR, 0.56, [95% CI, 0.33-0.94]) and Hispanic patients (HR, 0.54, [95% CI, 0.30-0.97]). There was no difference in cytokine release syndrome by race/ethnicity; however, higher rates of any-grade ICANS were observed in NH-white patients compared with other patients. These results provide important context when treating patients with R/R LBCL with axi-cel across different racial and ethnic groups. ZUMA-1 (NCT02348216) and ZUMA-7 (NCT03391466), both registered on ClinicalTrials.gov.

Symptom clusters and their impact on quality of life in multiple myeloma survivors: Secondary analysis of BMT CTN 0702 trial

Autologous haematopoietic cell transplantation (autoHCT) and continuous post-transplant maintenance therapy are the standard of care in transplant-eligible multiple myeloma (MM) patients. We sought to describe symptom burden and identify symptom clusters occurring in MM patients after autoHCT using data from the BMT CTN 0702 randomized controlled trial comparing the outcomes of three treatment interventions after an autoHCT in 758 MM patients. We analysed individual transplant-related symptoms assessed via the FACT-BMT questionnaire at enrolment and annually for 4-year post-autoHCT. We also described the effect the individual symptoms and symptom clusters have on quality of life (QoL). We identified three stable symptom clusters: malaise symptom cluster (lack of energy, feeling ill, having pain, experiencing nausea, loss of appetite), physical symptom cluster (having skin problems, tremors, worsening eyesight, change in taste, shortness of breath, frequent colds) and emotional symptom cluster (feeling sad, being nervous, experiencing sleep problems). Malaise and emotional symptom clusters have a greater impact on QoL than the physical symptoms cluster. Identifying these symptoms warrant additional support in terms of psychosocial support, in addition to treatment of the physical symptoms themselves.

Severity and organ distribution of chronic graft-versus-host disease with posttransplant cyclophosphamide-based versus methotrexate/calcineurin inhibitor-based allogeneic hematopoietic cell transplantation

The reduced risk of chronic graft-versus-host-disease (GVHD) with posttransplant cyclophosphamide (ptCy) in the setting of haploidentical related donor and more recently, with HLA-matched related and matched and mismatched unrelated donor allogeneic transplantation has been established. There is, however, paucity of data to show if ptCy impacts chronic GVHD pathogenesis, its phenotype and evolution after HCT regardless of the donor status. We examined the differences in chronic GVHD incidence and presentation in 314 consecutive patients after receiving their first allogeneic transplantation (HCT) using ptCy-based GVHD prophylaxis (ptCy-HCT; n = 120; including 95 with haploidentical related donor) versus conventional calcineurin inhibitor-based prophylaxis (CNI-MUD; n = 194) between 2012 and 2019. The 1-year cumulative incidence of all-grade chronic GVHD and moderate/severe chronic GVHD was 24% and 12%, respectively, after ptCy-HCT and 40% and 23% in the CNI-MUD recipients (p = 0.0003 and 0.007). Multivariable analysis confirmed that use of CNI-based GVHD prophylaxis and peripheral blood stem cell graft as the risk factors for chronic GVHD. The cumulative incidence of visceral (involving ≥1 of the following organs: liver, lungs, gastrointestinal tract, serous membranes) chronic GVHD was significantly higher with CNI-MUD vs. ptCy-HCT (27% vs. 15% at 1 year, p = 0.009). The incidence of moderate/severe visceral chronic GVHD was 20% in CNI-MUD group vs. 7.7% in the ptCy-HCT group at 1 year (p = 0.002). In addition, significantly fewer ptCy-HCT recipients developed severe chronic GVHD in ≥3 organs (0.8%) vs. 8.8% in the CNI-MUD group at 1-year posttransplant (p = 0.004). There was no significant different in relapse, non-relapse mortality, and relapse-free and overall survival between the two groups. Further investigation is needed to confirm that reduced risk and severity of chronic GVHD, less visceral organ distribution with ptCy-HCT leads to improved quality of life.

Axicabtagene Ciloleucel versus Tisagenlecleucel for Relapsed or Refractory Large B Cell Lymphoma: A Systematic Review and Meta-Analysis

Axicabtagene ciloleucel (axi-cel) and tisagenlecleucel (tisa-cel) are CD19-directed chimeric antigen receptor T cell (CAR-T) therapies approved for relapsed/refractory aggressive large B cell lymphoma (LBCL). Significant costs and complex manufacturing underscore the importance of evidence-based counseling regarding the outcomes of these treatments. With the aim of examining the efficacy and safety of axi-cel versus tisa-cel in patients with relapsed/refractory aggressive LBCL, we performed a systematic literature search of comparative studies evaluating outcomes in relapsed/refractory aggressive LBCL after treatment with axi-cel or tisa-cel. We calculated odds ratios (ORs) and 95% confidence intervals (CIs) for response, progression-free survival (PFS), overall survival (OS), cytokine release syndrome (CRS), immune effector cell-associated neurotoxicity syndrome (ICANS), and hematotoxicity. Meta-analysis and meta-regression were used to generate summary statistics. A total of 2372 participants were included in the 8 studies in our analysis. The dropout rate between apheresis and infusion was 13% for axi-cel versus 18% for tisa-cel, and the median time from apheresis to infusion was 32 days versus 45 days. Axi-cel showed higher odds for a complete response (OR, 1.65; P < .001) and was associated with higher odds for PFS at 1 year after infusion (OR, .60; P < .001). OS appeared to be improved with axi-cel (OR, .84; 95% CI, .68 to 1.02; P = .08), whereas the cumulative incidence of nonrelapse mortality (NRM) was 11.5% for axi-cel versus 3.7% for tisa-cel (P = .002). The main predictors for survival were lactate dehydrogenase level, Eastern Cooperative Oncology Group Performance Status, and response to bridging, and axi-cel maintained superior efficacy even in elderly patients. In terms of safety, axi-cel was associated with significantly higher odds of any-grade CRS (OR, 3.23; P < .001), but not of grade ≥3 CRS (P = .92). Axi-cel was associated with significantly higher odds of severe ICANS grade ≥3 (OR, 4.03; P < .001). In terms of hematotoxicity, axi-cel was significantly associated with higher odds of severe neutropenia at 1 month after infusion (OR, 2.06; P = .003). As a result, axi-cel was associated with significantly greater resource utilization, including prolonged hospital stay, more frequent intensive care admission, and use of agents such as tocilizumab for toxicity management. We provide strong evidence of the greater efficacy of axi-cel versus tisa-cel in relapsed/refractory aggressive LBCL. The higher toxicity and NRM seen with axi-cel might not counterbalance the overall results, highlighting the need for timely intervention and careful selection of patients, balancing resource utilization and clinical benefit.

Chimeric Antigen Receptor T Cell Therapy for Myeloma: Where Are We Now and What Is Needed to Move Chimeric Antigen Receptor T Cells Forward to Earlier Lines of Therapy? Expert Panel Opinion from the American Society for Transplantation and Cellular Therapy

Since 2021, 2 B cell maturation antigen (BCMA)-directed chimeric antigen receptor T cell (CAR-T) therapies-idecabtagene vicleucel (ide-cel), and ciltacabtagene autoleucel (cilta-cel)-have been approved by the US Food and Drug Administration (FDA) for treating relapsed or refractory multiple myeloma (RRMM) after 4 or more prior lines of therapy, including an immunomodulatory drug, a proteasome inhibitor, and an anti-CD38 antibody. The 2 products have shown unprecedented activity in RRMM, but relapses remain common, and access to and safety of CAR-T therapy in patients with rapidly progressing advanced disease are not ideal. Sequencing CAR-T therapy with other options, including the 2 recently approved BCMA-directed T cell-engaging bispecific antibodies teclistamab and elranatamab, has become increasingly challenging owing to data showing inferior outcomes from CAR-T therapy after prior BCMA-directed therapy. This has led to the consideration of CAR-T therapy earlier in the course of disease for myeloma, when T cells are potentially healthier and the myeloma is less aggressive. To address the question of earlier use of CAR-T therapy, several trials are either ongoing or planned, and results have recently been reported for 2 randomized trials of CAR-T therapy showing improved progression-free survival compared to standard of care therapy in second-line (CARTITUDE-4) or third-line therapy (KarMMA-3). With the anticipation of the FDA possibly expanding approval of CAR-T to earlier lines of myeloma therapy, the American Society for Transplantation and Cellular Therapy convened a group of experts to provide a comprehensive review of the studies that led to the approval of CAR-T therapy in late-line therapy for myeloma, discuss the recently reported and ongoing studies designed to move CAR-T therapy to earlier lines of therapy, and share insights and considerations for sequencing therapy and optimization of patient selection for BCMA-directed therapies in current practice.

Randomized Phase II Trial of Dendritic Cell/Myeloma Fusion Vaccine with Lenalidomide Maintenance after Upfront Autologous Hematopoietic Cell Transplantation for Multiple Myeloma: BMT CTN 1401

PURPOSE

Vaccination with dendritic cell (DC)/multiple myeloma (MM) fusions has been shown to induce the expansion of circulating multiple myeloma-reactive lymphocytes and consolidation of clinical response following autologous hematopoietic cell transplant (auto-HCT).

PATIENTS AND METHODS

In this randomized phase II trial (NCT02728102), we assessed the effect of DC/MM fusion vaccination, GM-CSF, and lenalidomide maintenance as compared with control arms of GM-CSF and lenalidomide or lenalidomide maintenance alone on clinical response rates and induction of multiple myeloma-specific immunity at 1-year posttransplant.

RESULTS

The study enrolled 203 patients, with 140 randomized posttransplantation. Vaccine production was successful in 63 of 68 patients. At 1 year, rates of CR were 52.9% (vaccine) and 50% (control; P = 0.37, 80% CI 44.5%, 61.3%, and 41.6%, 58.4%, respectively), and rates of VGPR or better were 85.3% (vaccine) and 77.8% (control; P = 0.2). Conversion to CR at 1 year was 34.8% (vaccine) and 27.3% (control; P = 0.4). Vaccination induced a statistically significant expansion of multiple myeloma-reactive T cells at 1 year compared with before vaccination (P = 0.024) and in contrast to the nonvaccine arm (P = 0.026). Single-cell transcriptomics revealed clonotypic expansion of activated CD8 cells and shared dominant clonotypes between patients at 1-year posttransplant.

CONCLUSIONS

DC/MM fusion vaccination with lenalidomide did not result in a statistically significant increase in CR rates at 1 year posttransplant but was associated with a significant increase in circulating multiple myeloma-reactive lymphocytes indicative of tumor-specific immunity. Site-specific production of a personalized cell therapy with centralized product characterization was effectively accomplished in the context of a multicenter cooperative group study. See related commentary by Qazilbash and Kwak, p. 4703.

INSPIRED Symposium Part 1: Clinical Variables Associated with Improved Outcomes for Children and Young Adults treated with Chimeric Antigen Receptor T cells for B cell Acute Lymphoblastic Leukemia

Chimeric antigen receptor (CAR) T cell therapy (CAR-T) targeting the CD19 antigen on B cell acute lymphoblastic leukemia (B-ALL) has transitioned from a highly investigational therapy with limited access to a commercial therapy with established toxicities, response and survival rates, and access in numerous countries. With more than a decade of clinical study and 5 years of commercial access, data showing associations with success and failure have emerged. To address functional limitations of CAR-T and overcome constrained sample sizes when studying single-trial or single-center data, collaborative groups, including the Pediatric Real World CAR Consortium, the CAR-Multicenter Analysis, the Center for International Blood and Marrow Transplant Research, and the International BFM Study Group, among others, have been retrospectively interrogating the amassed clinical experience. The high patient numbers and varied clinical experiences compiled by these groups have defined clinical variables impacting CAR-T outcomes. Here we review published CAR-T trials and consortium/collaborative outcomes to establish variables associated with optimal response to CAR-T in children and young adults with B-ALL. We focus on findings with clinical relevance that have emerged, including data implicating pretreatment disease burden, presence of extramedullary disease, nonresponse to prior CD19 antigen targeting (blinatumomab therapy), CAR T cell dose, and fludarabine pharmacokinetics as factors impacting post-CAR-T survival. Additionally, we address the role of collaborative efforts going forward in guiding clinical practice evolution and further optimizing post-CAR-T outcomes.

A Multicenter Phase II, Double-Blind, Placebo-Controlled Trial of Maintenance Ixazomib After Allogeneic Transplantation for High-Risk Multiple Myeloma: Results of the Blood and Marrow Transplant Clinical Trials Network 1302 Trial

The role of allogeneic hematopoietic cell transplantation (allo-HCT) followed by maintenance therapy in high-risk multiple myeloma (MM) remains controversial. We evaluated the efficacy of ixazomib maintenance therapy after reduced-intensity conditioning allo-HCT from HLA-matched donors in patients with high-risk MM. The primary study endpoint was progression-free survival (PFS) postrandomization, treated as a time to event. Secondary endpoints were grade II-IV and grade II-IV acute graft-versus-host-disease (GVHD), chronic GVHD, best response, disease progression, nonrelapse mortality (NRM), overall survival (OS), toxicity, infection, and health-related quality of life. In this phase 2, double-blinded, prospective multicenter trial, we randomized patients with high-risk MM (ie, those with poor-risk cytogenetics, plasma cell leukemia, or relapsing within 24 months after autologous HCT) to ixazomib (3 mg on days 1, 8, and 15) or placebo after allo-HCT. The conditioning regimen included fludarabine/melphalan/bortezomib with tacrolimus plus methotrexate for GVHD. Fifty-seven patients were enrolled, of whom 52 (91.2%) underwent allo-HCT and 43 (82.7%) were randomized to ixazomib versus placebo. At 21 months postrandomization, the ixazomib and placebo groups had similar PFS (55.3% versus 59.1%; P = 1.00) and OS (94.7% versus 86.4%; P = .17). The cumulative incidences of grade III-IV acute GVHD at 100 days (9.5% versus 0%) and chronic GVHD at 12 months (68.6% versus 63.6%) also were similar in the 2 groups. The secondary analysis showed that at 24 months post-allo-HCT, PFS and OS were 52% and 82%, respectively, with a corresponding NRM of 11.7%. These results demonstrate the safety and durable disease control with allo-HCT in high-risk MM patients. We could not adequately assess the efficacy of ixazomib maintenance because the trial terminated early owing to enrollment delays, but there was no indication of any impact on outcomes.

Associations of minor histocompatibility antigens with outcomes following allogeneic hematopoietic cell transplantation

The role of minor histocompatibility antigens (mHAs) in mediating graft versus leukemia and graft versus host disease (GvHD) following allogeneic hematopoietic cell transplantation (alloHCT) is recognized but not well-characterized. By implementing improved methods for mHA prediction in two large patient cohorts, this study aimed to comprehensively explore the role of mHAs in alloHCT by analyzing whether (1) the number of predicted mHAs, or (2) individual mHAs are associated with clinical outcomes. The study population consisted of 2249 donor-recipient pairs treated for acute myeloid leukemia and myelodysplastic syndrome with alloHCT. A Cox proportional hazard model showed that patients with a class I mHA count greater than the population median had an increased hazard of GvHD mortality (hazard ratio [HR] = 1.39, 95% confidence interval [CI] = 1.01, 1.77, p = .046). Competing risk analyses identified the class I mHAs DLRCKYISL (GSTP), WEHGPTSLL (CRISPLD2), and STSPTTNVL (SERPINF2) were associated with increased GVHD mortality (HR = 2.84, 95% CI = 1.52, 5.31, p = .01), decreased leukemia-free survival (LFS) (HR = 1.94, 95% CI = 1.27, 2.95, p = .044), and increased disease-related mortality (DRM) (HR = 2.32, 95% CI = 1.5, 3.6, p = .008), respectively. One class II mHA YQEIAAIPSAGRERQ (TACC2) was associated with increased risk of treatment-related mortality (TRM) (HR = 3.05, 95% CI = 1.75, 5.31, p = .02). WEHGPTSLL and STSPTTNVL were both present within HLA haplotype B*40:01-C*03:04 and showed a positive dose-response relationship with increased all-cause mortality and DRM and decreased LFS, indicating these two mHAs contribute to the risk of mortality in an additive manner. Our study reports the first large-scale investigation of the associations of predicted mHA peptides with clinical outcomes following alloHCT.

Shared graft-versus-leukemia minor histocompatibility antigens in DISCOVeRY-BMT

T-cell responses to minor histocompatibility antigens (mHAs) mediate graft-versus-leukemia (GVL) effects and graft-versus-host disease (GVHD) in allogeneic hematopoietic cell transplantation. Therapies that boost T-cell responses improve allogeneic hematopoietic cell transplant (alloHCT) efficacy but are limited by concurrent increases in the incidence and severity of GVHD. mHAs with expression restricted to hematopoietic tissue (GVL mHAs) are attractive targets for driving GVL without causing GVHD. Prior work to identify mHAs has focused on a small set of mHAs or population-level single-nucleotide polymorphism-association studies. We report the discovery of a large set of novel GVL mHAs based on predicted immunogenicity, tissue expression, and degree of sharing among donor-recipient pairs (DRPs) in the DISCOVeRY-BMT data set of 3231 alloHCT DRPs. The total number of predicted mHAs varied by HLA allele, and the total number and number of each class of mHA significantly differed by recipient genomic ancestry group. From the pool of predicted mHAs, we identified the smallest sets of GVL mHAs needed to cover 100% of DRPs with a given HLA allele. We used mass spectrometry to search for high-population frequency mHAs for 3 common HLA alleles. We validated 24 predicted novel GVL mHAs that are found cumulatively within 98.8%, 60.7%, and 78.9% of DRPs within DISCOVeRY-BMT that express HLA-A∗02:01, HLA-B∗35:01, and HLA-C∗07:02, respectively. We confirmed the immunogenicity of an example novel mHA via T-cell coculture with peptide-pulsed dendritic cells. This work demonstrates that the identification of shared mHAs is a feasible and promising technique for expanding mHA-targeting immunotherapeutics.

Abstract 6785: Dendritic cell/myeloma fusion vaccine with lenalidomide maintenance following autologous hematopoietic cell transplant induced T cell activation and expansion

Introduction: Multiple myeloma (MM), a clonal disorder of terminally differentiated plasma cells, is the second most common hematologic malignancy with ~57.9% 5-year survival rate. Current MM therapies are not curative and in most patients MM relapse. Aiming to restore antitumor immunity and counteract MM evolution, we have developed a personalized dendritic(DC)/MM cell fusion vaccine, whereby several tumor antigens are presented in the context of DC mediated co-stimulation. BMT CTN 1401 is a multicenter randomized phase II clinical trial (NCT02728102) evaluating the efficacy of the DC/MM vaccine combined with lenalidomide maintenance (Len) after autoHCT. 203 patients were enrolled from 18 centers. Aim: To evaluate the impact of the DC/MM vaccine on the establishment of anti-MM immune response we profiled the peripheral blood (PB) immune landscape at the single-cell level, with particular focus on the T cell compartment.

Method: We performed single-cell immunoprofiling (gene expression + V(D)J sequencing) on 40 patients (3xDC/MM vaccine/Len/GM-CSF: N=20; Len/GM-CSF: N=10; Len: N=10). 160 PB mononuclear cells (PBMC) samples were collected at enrollment, prior to Len, after 1 and 3 vaccines and were processed using the 10x Genomics single cell 5' assay. Here we present the analysis relative to 52 PBMC samples from 13 vaccinated patients included in the initial study cohort. The remaining 108 PBMC samples have already been subjected to single-cell immunoprofiling and the analysis is ongoing.

Results: 309,423 cells passed quality-check identifying 47 cell populations, corresponding to 20 major compartments. The T cell compartment (146,373 cells) was divided into 14 different cell populations including activated CD8, CD4, and NKT cells that exhibited a gradual increase during the course of the study. Relatively, TCR sequencing demonstrated a recovery of T cell clonal diversity and a progressive rise in the frequency of expanded clonotypes within the activated CD4 and cytotoxic T cell populations after vaccination. Consistently, we observed a progressively raised number of shared TCR clonotypes within the activated CD8 and CD4 T cell subsets. The identification of common epitope/paratope hotspots among the expanded clonotypes and the different patients revealed a higher proportion of shared TCR clonotype groups across patients after vaccination compared to the early post-transplant period, predominantly after 3 vaccinations.

Conclusions: Assessment of PBMC samples from 13 vaccinated patients provided a detailed picture of the PBMC landscape. The constant T cell expansion in patients following vaccination coupled with the shared paratope/epitope hotspots and TCR signatures among patients indicated the TCR cross-reactivity and suggested for the establishment of an anti-MM immune response.

Citation Format: Giulia Cheloni, Dimitra Karagkouni, Daniela Torres, David J. Chung, Nina Shah, Natalie S. Callander, Thinle Chodon, Yvonne Efebera, Nancy Geller, Peiman Hematti, Hillard Lazarus, Ehsan Malek, Philip L. McCarthy, Ajay K. Nooka, Jacalyn Rosenblatt, Aaron P. Rapoport, Robert J. Soiffer, Dina Stroopinsky, Edmund K. Waller, Marcelo C. Pasquini, Ioannis Vlachos, David Avigan. Dendritic cell/myeloma fusion vaccine with lenalidomide maintenance following autologous hematopoietic cell transplant induced T cell activation and expansion [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6785.

An Analysis of the Worldwide Utilization of Hematopoietic Stem Cell Transplantation for Acute Myeloid Leukemia

Acute myeloid leukemia (AML) has an aggressive course and a historically dismal prognosis. For many patients, hematopoietic stem cell transplantation (HSCT) represents the best option for cure, but access, utilization, and health inequities on a global scale remain poorly elucidated. We wanted to describe patterns of global HSCT use in AML for a better understanding of global access, practices, and unmet needs internationally. Estimates of AML incident cases in 2016 were obtained from the Global Burden of Disease 2019 study. HSCT activities were collected from 2009 to 2016 by the Worldwide Network for Blood and Marrow Transplantation through its member organizations. The primary endpoint was global and regional use (number of HSCT) and utilization of HSCT (number of HSCT/number of incident cases) for AML. Secondary outcomes included trends from 2009 to 2016 in donor type, stem cell source, and remission status at time of HSCT. Global AML incidence has steadily increased, from 102,000 (95% uncertainty interval: 90,200-108,000) in 2009 to 118,000 (104,000-126,000) in 2016 (16.2%). Over the same period, a 54.9% increase from 9659 to 14,965 HSCT/yr was observed globally, driven by an increase in allogeneic (64.9%) with a reduction in autologous (-34.9%) HSCT. Although the highest numbers of HSCT continue to be performed in high-resource regions, the largest increases were seen in resource-constrained regions (94.6% in Africa/East Mediterranean Region [AFR/EMR]; 34.7% in America-Nord Region [AMR-N]). HSCT utilization was skewed toward high-resource regions (in 2016: AMR-N 18.4%, Europe [EUR] 17.9%, South-East Asia/Western Pacific Region [SEAR/WPR] 11.7%, America-South Region [AMR-S] 4.5%, and AFR/EMR 2.8%). For patients <70 years of age, this difference in utilization was widened; AMR-N had the highest allogeneic utilization rate, increasing from 2009 to 2016 (30.6% to 39.9%) with continued low utilization observed in AFR/EMR (1.7% to 2.9%) and AMR-S (3.5% to 5.4%). Across all regions, total HSCT for AML in first complete remission (CR1) increased (from 44.1% to 59.0%). Patterns of donor stem cell source from related versus unrelated donors varied widely by geographic region. SEAR/WPR had a 130.2% increase in related donors from 2009 to 2016, and >95% HSCT donors in AFR/EMR were related; in comparison, AMR-N and EUR have a predilection for unrelated HSCT. Globally, the allogeneic HSCT stem cell source was predominantly peripheral blood (69.7% of total HSCT in 2009 increased to 78.6% in 2016). Autologous HSCT decreased in all regions from 2009 to 2016 except in SEAR/WPR (18.9%). HSCT remains a central curative treatment modality in AML. Allogeneic HSCT for AML is rising globally, but there are marked variations in regional utilization and practices, including types of graft source. Resource-constrained regions have the largest growth in HSCT use, but utilization rates remain low, with a predilection for familial-related donor sources and are typically offered in CR1. Further studies are necessary to elucidate the reasons, including economic factors, to understand and address these health inequalities and improve discrepancies in use of HSCT as a potentially curative treatment globally.

Multi-Stakeholder Qualitative Interviews to Inform Measurement of Patient Reported Outcomes After CAR-T

Toxicities after chimeric antigen receptor T cell (CAR-T) therapy are well known, yet the patient experience during and after CAR-T therapy has not been well described outside of the trial setting. We explored the patient experience after CAR-T therapy to inform the patient-reported outcomes (PRO) measurement approach for the Center for International Blood and Marrow Transplant Research (CIBMTR). We recruited (1) adult patients diagnosed with a hematologic malignancy 14 days to 6 months after receiving a commercial CAR T cell product who had agreed to be contacted by the CIBMTR, (2) caregivers of those patients, and (3) clinical experts in CAR-T therapy. Telephone interviews were conducted following a semistructured guide that included open-ended questions about symptoms and functioning. We conducted a systematic content analysis of each transcript using prespecified codes representing common domains of health, as well as open coding for emergent themes. Forty patients at 29 centers, 15 of their caregivers, and 15 experts from 9 centers participated, representing diversity with respect to age, sex, race/ethnicity, and years in practice (experts). Patients, caregivers, and experts shared largely consistent impressions of the patient experience after CAR-T therapy. Commonly described themes included anxiety, cognitive dysfunction, depression, fatigue, pain, impaired physical function, gastrointestinal symptoms, sexual dysfunction, sleep difficulties, need for support, financial impact, hospitalization, communication with healthcare providers, and the COVID-19 pandemic. Limitations in patients' ability to participate in social roles and activities was the most prevalent theme, found in nearly all interviews. In the setting of CAR-T therapy, a multidimensional approach to PRO measurement is needed that includes physical, mental, and social health, as well as the financial impact of this novel treatment. High-quality existing PRO tools are available to measure these concepts. Results will inform the CIBMTR measurement of PROs after CAR-T therapy and may be applicable to other CAR-T studies that aim to represent patient experiences.

Real-world data showing trends and outcomes by race and ethnicity in allogeneic hematopoietic cell transplantation: a report from the Center for International Blood and Marrow Transplant Research

BACKGROUND

Use of human leukocyte antigen (HLA)-mismatched donors could enable more patients with ethnically diverse backgrounds to receive allogeneic hematopoietic cell transplantation (HCT) in the United States. However, real-world trends and outcomes following mismatched donor HCT for diverse patients remain largely undefined.

OBJECTIVE

To determine whether mismatched donor platforms have increased access to allogeneic HCT for ethnically diverse patients, particularly through the application of novel graft-versus-host disease (GvHD) prophylaxis regimens, and if outcomes for diverse patients were comparable to those of non-Hispanic White patients.

DESIGN

Observational cross-sectional study using real-world data from the Center for International Blood and Marrow Transplant Research (CIBMTR) registry. All patients receiving their first allogeneic HCT in the U.S. from 2009-2020 with focus on transplants performed in 2020 were included. Data from patients receiving allogeneic HCT using bone marrow, peripheral blood or cord blood from HLA-matched or mismatched related and unrelated donors was analyzed. Specifically, relative proportions of allogeneic HCT were generated as percent of total for donor type and for patient age, disease indication, GvHD prophylaxis, and race and ethnicity. Causes of death were summarized using frequencies, and the Kaplan-Meier estimator was used for estimating overall survival.

RESULTS

Compared to matched related donor and matched unrelated donor HCT, more ethnically diverse patients received mismatched unrelated donor, haploidentical donor, and cord blood HCT. Matched unrelated donor remains the most common donor type, but use of haploidentical donors has increased significantly over the last 5 years. Paralleling the increase in haploidentical HCT is the increased use of post-transplant cyclophosphamide (PTCy) as GvHD prophylaxis. Relative to older transplant eras, the most contemporary transplant era associates with the highest survival rates following allogeneic HCT irrespective of patient race and ethnicity. However, disease relapse remains the primary cause of death for both adult and pediatric allogeneic HCT recipients by donor type and across all patient race and ethnicity groups.

CONCLUSIONS

Ethnically diverse patients are undergoing allogeneic HCTs at higher rates largely through the use of alternative donor platforms incorporating PTCy. Maintaining access to potential life-saving allogeneic HCT using alternative donors and novel GvHD prophylaxis strategies and improving HCT outcomes, particularly disease relapse, are urgent clinical needs.

T Cell-Depleted Peripheral Blood versus Unmanipulated Bone Marrow in Matched Sibling Transplantation for Aplastic Anemia

Bone marrow (BM) is the recommended stem cell source for hematopoietic stem cell transplantation (HSCT) from matched sibling donors (MSDs) in patients with severe aplastic anemia (SAA) for its superior survival and graft-versus-host disease (GVHD) outcomes compared to recipients of unmanipulated peripheral blood (PB) HSCT. Nevertheless, no studies comparing BM with ex vivo T cell-depleted (TCD) PB have been reported to date. The aim of the present study was to compare the transplantation outcomes of MSD HSCT recipients with SAA using PB (with partial ex vivo TCD targeted cell dose grafts) with those of MSD HSCT recipients with SAA using unmanipulated BM. We performed a matched-pair analysis of MSD-HSCT using TCD PB in a single institution with unmanipulated BM MSD-HSCT in the United States between 2013 and 2019 reported to the Center for International Blood and Marrow Transplant Research. We compared 23 recipients of TCD PB HSCT for SAA (cases) and 69 recipients of unmanipulated BM grafts (controls) matched for age, Karnofsky Performance Status, Hematopoietic Cell Transplantation-Specific Comorbidity Index, time from diagnosis to transplantation, and recipient cytomegalovirus serostatus. We found significantly faster neutrophil and platelet recovery in the TCD PB cohort (P < .001 and P = .03, respectively), as well as a lower incidence of grade II-IV acute GVHD (0% versus 17%; P = .05) and similar overall survival (96% versus 97% at 3 years; P = .8). Our study shows that TCD PB can be considered a safe source for MSD-HSCT in patients with SAA, with potential advantages in engraftment and GVHD that could challenge the standard with BM. These findings provide a basis for future research in a prospective controlled clinical trial.

Trajectories of quality of life recovery and symptom burden after autologous hematopoietic cell transplantation in multiple myeloma

Early autologous hematopoietic cell transplantation (AHCT) with post-transplant maintenance therapy is standard of care in multiple myeloma (MM). While short-term quality of life (QOL) deterioration after AHCT is known, the long-term trajectories and symptom burden after transplantation are largely unknown. Toward this goal, a secondary analysis of QOL data of the BMT CTN 0702, a randomized controlled trial comparing outcomes of three treatment interventions after a single AHCT (N = 758), was conducted. FACT-BMT scores up to 4 years post-AHCT were analyzed. Symptom burden was studied using responses to 17 individual symptoms dichotomized as 'none/mild' for scores 0-2 and 'moderate/severe' for scores of 3 or 4. Patients with no moderate/severe symptom ratings were considered to have low symptom burden at 1-year. Mean age at enrollment was 55.5 years with 17% African Americans. Median follow-up was 6 years (range, 0.4-8.5 years). FACT-BMT scores improved between enrollment and 1-year and remained stable thereafter. Low symptom burden was reported by 27% of patients at baseline, 38% at 1-year, and 32% at 4 years post-AHCT. Predictors of low symptom burden at 1-year included low symptom burden at baseline: OR 2.7 (1.8-4.1), p < 0.0001; older age: OR 2.1 (1.3-3.2), p = 0.0007; and was related to being employed: OR 2.1 (1.4-3.2), p = 0.0004). We conclude that MM survivors who achieve disease control after AHCT have excellent recovery of FACT-BMT and subscale scores to population norms by 1-year post-transplant, though many patients continue to report moderate to severe severity in some symptoms at 1-year and beyond.

Real-World Evidence of Axicabtagene Ciloleucel for the Treatment of Large B Cell Lymphoma in the United States

Axicabtagene ciloleucel (axi-cel) is a standard-of-care for patients with relapsed or refractory (r/r) large B cell lymphoma who have received 2 or more lines of prior therapy. Patients receiving axi-cel in the real world could have broader a demographic, disease, and treatment profile compared with that of the cohort in the pivotal ZUMA-1 trial. The present study was conducted to evaluate the outcomes of axi-cel therapy in the real-world setting. A total of 1297 patients receiving commercial axi-cel between 2017 and 2020 were selected from the Center for International Blood and Marrow Transplant Research's data registry, of whom 739 (57%) would have been ineligible for inclusion in the ZUMA-1 cohort. Efficacy and safety outcomes were described for the entire cohort and by ZUMA-1 eligibility. Their associations with age, Eastern Cooperative Oncology Group Performance Score, and comorbidities were evaluated using multivariable logistic and Cox regressions. At a median follow-up of 12.9 months, the overall response rate (ORR) was 73%, with a 56% complete response (CR) rate. Median overall survival (OS) and progression-free survival (PFS) were 21.8 months (95% confidence interval [CI], 17.4 to 28.8 months) and 8.6 months (95% CI, 6.5 to 12.1 months), respectively. Duration of response (DOR) was comparable in the ZUMA-1 ineligible patients and ZUMA-1 eligible patients (62% by 1 year [95% CI, 57% to 66%] versus 67% [95% CI, 62% to 72%]). Patients age ≥65 years had favorable ORR (odds ratio [OR], 1.39; 95% CI, 1.05 to 1.83) despite having a higher risk of cytokine release syndrome (CRS) (OR, 1.41; 95% CI, 1.02 to 1.94) and immune effector cell-associated neurotoxicity syndrome (ICANS) (OR, 1.77; 95% CI, 1.39-2.26). Eastern Cooperative Oncology Group Performance Score ≥2 was associated with inferior efficacy outcomes (OR for ORR, 0.32; 95% CI, 0.18-0.56; hazard ratio [HR] for OS, 3.27; 95% CI, 2.37 to 4.52) and higher incidence of ICANS (OR, 2.63; 95% CI, 1.40 to 4.93). The patients ineligible for ZUMA-1 still had a durable response with axi-cel. Elderly patients had favorable efficacy outcomes despite higher rates of CRS and ICANS. Patient selection for standard-of-care axi-cel should consider comorbidities and risk-to-benefit ratio rather than be based strictly on ZUMA-1 eligibility.

Proceedings from the Blood and Marrow Transplant Clinical Trials Network Myeloma Intergroup Workshop on Immune and Cellular Therapy in Multiple Myeloma

The Blood and Marrow Transplant Clinical Trials Network (BMT CTN) Myeloma Intergroup conducted a workshop on Immune and Cellular Therapy in Multiple Myeloma on January 7, 2022. This workshop included presentations by basic, translational, and clinical researchers with expertise in plasma cell dyscrasias. Four main topics were discussed: platforms for myeloma disease evaluation, insights into pathophysiology, therapeutic target and resistance mechanisms, and cellular therapy for multiple myeloma. Here we provide a comprehensive summary of these workshop presentations.

Triplet Therapy, Transplantation, and Maintenance until Progression in Myeloma

BACKGROUND

In patients with newly diagnosed multiple myeloma, the effect of adding autologous stem-cell transplantation (ASCT) to triplet therapy (lenalidomide, bortezomib, and dexamethasone [RVD]), followed by lenalidomide maintenance therapy until disease progression, is unknown.

METHODS

In this phase 3 trial, adults (18 to 65 years of age) with symptomatic myeloma received one cycle of RVD. We randomly assigned these patients, in a 1:1 ratio, to receive two additional RVD cycles plus stem-cell mobilization, followed by either five additional RVD cycles (the RVD-alone group) or high-dose melphalan plus ASCT followed by two additional RVD cycles (the transplantation group). Both groups received lenalidomide until disease progression, unacceptable side effects, or both. The primary end point was progression-free survival.

RESULTS

Among 357 patients in the RVD-alone group and 365 in the transplantation group, at a median follow-up of 76.0 months, 328 events of disease progression or death occurred; the risk was 53% higher in the RVD-alone group than in the transplantation group (hazard ratio, 1.53; 95% confidence interval [CI], 1.23 to 1.91; P<0.001); median progression-free survival was 46.2 months and 67.5 months. The percentage of patients with a partial response or better was 95.0% in the RVD-alone group and 97.5% in the transplantation group (P = 0.55); 42.0% and 46.8%, respectively, had a complete response or better (P = 0.99). Treatment-related adverse events of grade 3 or higher occurred in 78.2% and 94.2%, respectively; 5-year survival was 79.2% and 80.7% (hazard ratio for death, 1.10; 95% CI, 0.73 to 1.65).

CONCLUSIONS

Among adults with multiple myeloma, RVD plus ASCT was associated with longer progression-free survival than RVD alone. No overall survival benefit was observed. (Funded by the National Heart, Lung, and Blood Institute and others; DETERMINATION ClinicalTrials.gov number, NCT01208662.).

Lenalidomide, bortezomib, and dexamethasone (RVd) ± autologous stem cell transplantation (ASCT) and R maintenance to progression for newly diagnosed multiple myeloma (NDMM): The phase 3 DETERMINATION trial

LBA4

Background: Optimal use of triplet/quadruplet induction, ASCT, and R-based maintenance in patients (pts) with NDMM who are eligible for transplant continues to evolve. The IFM 2009 trial, which used R maintenance for 1 year (y), showed progression-free survival (PFS; median, 35.0 vs. 47.3 months [mos]) but no overall survival benefit (OS; 60 vs. 62% at 8 y; median follow-up, 89.8 mos) with RVd + ASCT vs. RVd alone in the setting of multiple effective options at relapse, including ASCT at first relapse in 77% of pts (Attal M et al, N Engl J Med 2017; Perrot A et al, ASH 2020). We report primary data from our US DETERMINATION trial, which used R maintenance until progression. Methods: Pts with NDMM aged 18-65 y were randomly assigned to receive 3 RVd cycles, stem cell mobilization, and then 5 more RVd cycles (Arm A) or IV melphalan 200 mg/m2 + ASCT and 2 RVd cycles (Arm B). Each 21-d RVd cycle comprised PO R 25 mg (d 1-14), IV/SC bortezomib 1.3 mg/m2 (d 1, 4, 8, 11), and PO dexamethasone 20/10 mg (cycles 1-3/≥ 4; d 1, 2, 4, 5, 8, 9, 11, 12). Both arms received R 10-15 mg/d maintenance until progression or intolerance. The primary endpoint was PFS (90% power to detect PFS hazard ratio [HR] of 1.43 [Arm A vs. B] with α = 0.05 on stratified two-sided log-rank test; full information: 329 events in 720 pts). Data cut-off was Dec 10, 2021. Results: 357 and 365 pts were randomly assigned to Arms A and B, respectively; median age was 57 and 55 y, 14% and 13% had ISS stage III MM, and 18% each had high-risk cytogenetics [t(4;14), t(14;16), del17p]. In the respective arms, 291 and 290 pts received R maintenance for a median duration of 36 and 41 mos. After median follow-up of 76 mos and 328 events, median PFS was 46.2 vs. 67.6 mos in Arm A vs. B (HR 1.53; 95% CI, 1.23–1.91; p < .0001). Best responses in pts assessed to date were 52 vs. 62% ≥ CR (p = .006), 79 vs. 83% ≥ VGPR and 94 vs. 96% ≥ PR; in 251 evaluable pts, rate of MRD negativity (10-5) was 37.3 vs. 52.1% (p = .021) within 1 y of maintenance. 63 vs. 53% of pts have received subsequent treatment; of Arm A, 22% had ASCT as first non-protocol therapy. With 90 vs. 88 pts having died in Arm A vs. B, 4-y OS was 84% (95% CI, 80–88%) vs. 85% (95% CI, 81–88%); HR 1.10 (95% CI, 0.81–1.47; p = .274). Grade ≥ 3 related adverse events were less common in Arm A vs. B (78 vs. 94%; hematologic: 61 vs. 90%, p < .0001); 10 vs. 11% had secondary malignancies (ALL, 7 vs. 3 pts, p = .22; AML/MDS, 0 vs. 10 pts, p = .002). Difference in mean change from baseline in EORTC QLQ-C30 global health status score was < 10 points throughout treatment except at RVd cycle 5 vs. post-ASCT (compliance rate, 75% vs. 55%; mean change +3.0 vs. –11.1; p < .0001). Whole-genome sequencing, additional QOL, and correlative analyses are ongoing. Conclusions: RVd ± ASCT and R maintenance to progression resulted in the longest median PFS reported for each approach, and a highly significant 21.4-mo gain in median PFS benefit using RVd + ASCT. No OS advantage has been observed to date. Clinical trial information: NCT01208662.

Real-world outcomes of axicabtagene ciloleucel (Axi-cel) for the treatment of large B-cell lymphoma (LBCL) by race and ethnicity

7571

Background: In clinical trials of CAR T-cell therapies and real-world studies published to date, there is a paucity of data on outcomes by race and ethnicity. Here, we examined outcomes by race and ethnicity among LBCL pts who received axi-cel in the real-world setting. Methods: A total of 1389 pts with LBCL were identified from a non-interventional post-authorization safety study with pts receiving commercial axi-cel between 10/2017 and 08/2020. Race (African American or Asian vs White) and ethnicity (Hispanic vs non-Hispanic) were self-reported by pts. Pts with rescinded consent, enrolled in trials, having prior non-HCT cellular therapy, primary CNS lymphoma, unknown comorbidity or data in query were excluded. Median follow-up was 12.7 mo. Outcomes included ORR, CR rate, DOR, PFS and OS, grade ≥ 3 CRS (Lee 2014 criteria) and ICANS (ASTCT consensus grade). ORR and CR were evaluated in pts with ≥ 180 days of follow-up. Kaplan-Meier estimates were calculated for PFS and OS. Multivariable analyses comparing race and ethnicity were conducted via logistic and Cox regression. Results: Among all, 1127 (81%) were White, 70 (5%) African American and 81 (6%) Asian; 152 (11%) were Hispanic including 104 White, 2 Black, and 1 Asian Hispanic. African Americans, compared to White, were younger (median age 55.5 vs 62.8 years), more likely to have pulmonary impairment (41% vs 28%) and tended to have longer time from diagnosis (≥ 12 mo 71% vs 59%). Hispanic pts were younger (median age 58.5 vs 62.6 years) than non-Hispanic pts. ORR was 74% (CR 57%, 12-mo PFS and OS 48% and 63%) for White, 57% (CR 45%, 12-mo PFS and OS 36% and 62%) for African American, 67% (CR 53%, 12-mo PFS and OS 55% and 65%) for Asian and 73% (CR 55%, 12-mo PFS and OS 50% and 65%) for Hispanic pts. Grade ≥ 3 CRS and ICANS occurred in 7% and 18% of African American, 10% and 19% of Asian, and 8% and 27% of White pts, respectively. Hispanic pts had lower rates of grade ≥ 3 CRS and ICANS (4% and 15%) vs non-Hispanic (9% and 27%). African American race was associated with inferior ORR (OR 0.40; 95% CI, 0.24-0.69) and CR rate (OR 0.55; 95% CI 0.32-0.93) vs White. Asian pts had favorable DOR compared to both White (HR 0.46; 95% CI 0.24-0.87) and African American (HR 0.39; 95% CI 0.17-0.88). No statistical differences were found in OS and PFS across races, nor in any efficacy outcome between Hispanic and non-Hispanic pts. Asian (OR 0.52; 95% CI 0.29-0.96 vs White) and Hispanic pts (OR 0.51; 95% CI 0.31-0.85 vs non-Hispanic) had lower risk of grade ≥ 3 ICANS. Conclusions: Overall, axi-cel showed favorable OS, PFS and safety profile regardless of race and ethnicity in the real-world setting. No notable differences in outcomes were observed for Hispanic or Asian pts. Lower response rates in African American pts noted here warrant further investigation including any underrepresentation not explained by a lower incidence rate for DLBCL (SEER), access to care, and disease burden.

Does recipient body mass index inform donor selection for allogeneic haematopoietic cell transplantation?

It is not known whether obesity has a differential effect on allogeneic haematopoietic cell transplantation outcomes with alternative donor types. We report the results of a retrospective registry study examining the effect of obesity [body mass index (BMI) > 30] on outcomes with alternative donors (haploidentical related donor with two or more mismatches and receiving post-transplant cyclophosphamide [haplo] and cord blood (CBU)] versus matched unrelated donor (MUD). Adult patients receiving haematopoietic cell transplantation for haematologic malignancy (2013-2017) (N = 16 182) using MUD (n = 11 801), haplo (n = 2894) and CBU (n = 1487) were included. The primary outcome was non-relapse mortality (NRM). The analysis demonstrated a significant, non-linear interaction between pretransplant BMI and the three donor groups for NRM: NRM risk was significantly higher with CBU compared to haplo at BMI 25-30 [hazard ratio (HR) 1.66-1.71, p < 0.05] and MUD transplants at a BMI of 25-45 (HR, 1.61-3.47, p < 0.05). The results demonstrated that NRM and survival outcomes are worse in overweight and obese transplant recipients (BMI ≥ 25) with one alternative donor type over MUD, although obesity does not appear to confer a uniform differential mortality risk with one donor type over the other. BMI may serve as a criterion for selecting a donor among the three (MUD, haplo and CBU) options, if matched sibling donor is not available.

Randomized Phase III BMT CTN Trial of Calcineurin Inhibitor-Free Chronic Graft-Versus-Host Disease Interventions in Myeloablative Hematopoietic Cell Transplantation for Hematologic Malignancies

PURPOSE

Calcineurin inhibitors (CNI) are standard components of graft-versus-host disease (GVHD) prophylaxis after hematopoietic cell transplantation (HCT). Prior data suggested that CNI-free approaches using donor T-cell depletion, either by ex vivo CD34 selection or in vivo post-transplant cyclophosphamide (PTCy) as a single agent, are associated with lower rates of chronic GVHD (cGVHD).

METHODS

This multicenter phase III trial randomly assigned patients with acute leukemia or myelodysplasia and an HLA-matched donor to receive CD34-selected peripheral blood stem cell, PTCy after a bone marrow (BM) graft, or tacrolimus and methotrexate after BM graft (control). The primary end point was cGVHD (moderate or severe) or relapse-free survival (CRFS).

RESULTS

Among 346 patients enrolled, 327 received HCT, 300 per protocol. Intent-to-treat rates of 2-year CRFS were 50.6% for CD34 selection (hazard ratio [HR] compared with control, 0.80; 95% CI, 0.56 to 1.15; P = .24), 48.1% for PTCy (HR, 0.86; 0.61 to 1.23; P = .41), and 41.0% for control. Corresponding rates of overall survival were 60.1% (HR, 1.74; 1.09 to 2.80; P = .02), 76.2% (HR, 1.02; 0.60 to 1.72; P = .95), and 76.1%. CD34 selection was associated with lower moderate to severe cGVHD (HR, 0.25; 0.12 to 0.52; P = .02) but higher transplant-related mortality (HR, 2.76; 1.26 to 6.06; P = .01). PTCy was associated with comparable cGVHD and survival outcomes to control, and a trend toward lower disease relapse (HR, 0.52; 0.28 to 0.96; P = .037).

CONCLUSION

CNI-free interventions as performed herein did not result in superior CRFS compared with tacrolimus and methotrexate with BM. Lower rates of moderate and severe cGVHD did not translate into improved survival.

The 2020 BMT CTN Myeloma Intergroup Workshop on Immune Profiling and Minimal Residual Disease Testing in Multiple Myeloma

The fifth annual Blood and Marrow Transplant Clinical Trials Network Myeloma Intergroup Workshop on Immune Profiling and Minimal Residual Disease Testing in Multiple Myeloma was conducted as one of the American Society of Hematology Annual Meeting Scientific Workshops on Thursday December 3, 2020. This workshop focused on four main topics: (1) integrating minimal residual disease into clinical trial design and practice; (2) the molecular and immunobiology of disease evolution and progression in myeloma; (3) adaptation of next-generation sequencing, next-generation flow cytometry, and cytometry by time of flight techniques; and (4) chimeric antigen receptor T-cell and other cellular therapies for myeloma. In this report, we provide a summary of the workshop presentations and discuss future directions in the field.

Novel genetic variants associated with mortality after unrelated donor allogeneic hematopoietic cell transplantation

BACKGROUND

Identification of non-human leukocyte antigen (HLA) genetic risk factors could improve survival after allogeneic blood or marrow transplant (BMT) through matching at additional loci or individualizing risk prediction. We hypothesized that non-HLA loci contributed significantly to 1-year overall survival (OS), disease related mortality (DRM) or transplant related mortality (TRM) after unrelated donor (URD)BMT.

METHODS

We performed a genome-wide association study (GWAS) in 2,887 acute myeloid leukemia (AML), myelodysplastic syndrome (MDS) and acute lymphoblastic leukemia (ALL) patients and their ≥8/8 HLA-matched URDs comprising two independent cohorts treated from 2000-2011.

FINDINGS

Using meta-analyses of both cohorts, genome-wide significant associations (p < 5 × 10^-8) were identified in: recipient genomes with OS at MBNL1 (rs9990017, HR = 1.4, 95% CI 1.24-1.56, p = 3.3 × 10^-8) and donor-recipient genotype mismatch with OS at LINC02774 (rs10927108, HR = 1.34, 95% CI 1.21-1.48, p = 2.0 × 10^-8); donor genomes with DRM at PCNX4 (rs79076914, HR = 1.7, 95% CI 1.41-2.05, p = 3.15 × 10^-8), LINC01194 (rs79498125, HR = 1.86, 95% CI 1.49-2.31, p = 2.84 × 10^-8), ARID5B (rs2167710, HR = 1.5, 95% CI 1.31-1.73, p = 6.9 × 10^-9) and CT49 (rs32250, HR = 1.44, 95% CI1.26-1.64, p = 2.6 × 10^-8); recipient genomes at PILRB with TRM (rs141591562, HR = 2.33, 95% CI 1.74-3.12, p = 1.26 × 10^-8) and donor-recipient genotype mismatch between EPGN and MTHF2DL with TRM (rs75868097, HR = 2.66, 95% CI 1.92-3.58, p = 4.6 × 10^-9). Results publicly available at https://fuma.ctglab.nl/browse.

INTERPRETATION

These data provide the first evidence that non-HLA common genetic variation at novel loci with biochemical function significantly impacts 1-year URD-BMT survival. Our findings have implications for donor selection, could guide treatment strategies and provide individualized risk prediction after future validation and functional studies.

FUNDING

This project was funded by grants from the National Institutes of Health, USA.

One and a half million hematopoietic stem cell transplants: continuous and differential improvement in worldwide access with the use of non-identical family donors

The Worldwide Network of Blood and Marrow Transplantation (WBMT) pursues the mission of promoting hematopoietic cell transplantation (HCT) for instance by evaluating activities through member societies, national registries and individual centers. In 2016, 82,718 first HCTs were reported from 1662 HCT teams in 86 of the 195 World Health Organization member states representing a global increase of 6.2% in autologous and 7.0% in allogeneic HCT and bringing the total to 1,298,897 procedures. Assuming a frequency of 84,000/year, 1.5 million HCTs had been performed by 2019 from 1957. Slightly more autologous (53.5%) than allogeneic and more related (53.6%) than unrelated HCTs were reported. A remarkable increase was noted in haploidentical related HCT for leukemias and lymphoproliferative diseases, but even more in non-malignant diseases. Transplant rates (TR; HCT/10 million population) varied according to region reaching 560.8 in North America, 438.5 in Europe, 76.7 in Latin America, 53.6 in South East Asia/Western Pacific (SEA/WPR) and 27.8 in African/East Mediterranean (AFR/EMR). Interestingly, haploidentical TR amounted to 32% in SEA/WPR and 26% in Latin America, but only 14% in Europe and EMR and 4.9% in North America of all allogeneic HCT. HCT team density (teams/10 million population) was highest in Europe (7.7) followed by North America (6.0), SEA/WPR (1.9), Latin America (1.6) and AFR/EMR (0.4). HCTs are increasing steadily worldwide with narrowing gaps between regions and greater increase in allogeneic compared to autologous activity. While related HCT is rising, largely due to increase in haploidentical HCT, unrelated is plateauing and cord blood in decline.

One and a half million hematopoietic stem cell transplants: continuous and differential improvement in worldwide access with the use of non-identical family donors

The Worldwide Network of Blood and Marrow Transplantation (WBMT) pursues the mission of promoting hematopoietic cell transplantation (HCT) for instance by evaluating activities through member societies, national registries and individual centers. In 2016, 82,718 first HCT were reported by 1,662 HCT teams in 86 of the 195 World Health Organization member states representing a global increase of 6.2% in autologous HCT and 7.0% in allogeneic HCT and bringing the total to 1,298,897 procedures. Assuming a frequency of 84,000/year, 1.5 million HCT were performed by 2019 since 1957. Slightly more autologous (53.5%) than allogeneic and more related (53.6%) than unrelated HCT were reported. A remarkable increase was noted in haploidentical related HCT for leukemias and lymphoproliferative diseases, but even more in non-malignant diseases. Transplant rates (TR; HCT/10 million population) varied according to region reaching 560.8 in North America, 438.5 in Europe, 76.7 in Latin America, 53.6 in South East Asia/Western Pacific (SEA/WPR) and 27.8 in African/East Mediterranean (AFR/EMR). Interestingly, haploidentical TR amounted to 32% in SEA/WPR and 26% in Latin America, but only 14% in Europe and EMR and 4.9% in North America of all allogeneic HCT. HCT team density (teams/10 million population) was highest in Europe (7.7) followed by North America (6.0), SEA/WPR (1.9), Latin America (1.6) and AFR/EMR (0.4). HCT are increasing steadily worldwide with narrowing gaps between regions and greater increase in allogeneic compared to autologous activity. While related HCT is rising, largely due to increase in haploidentical HCT, unrelated HCT is plateauing and cord blood HCT is in decline.

Beyond the storm - subacute toxicities and late effects in children receiving CAR T cells

As clinical advances with chimeric antigen receptor (CAR) T cells are increasingly described and the potential for extending their therapeutic benefit grows, optimizing the implementation of this therapeutic modality is imperative. The recognition and management of cytokine release syndrome (CRS) marked a milestone in this field; however, beyond the understanding gained in treating CRS, a host of additional toxicities and/or potential late effects of CAR T cell therapy warrant further investigation. A multicentre initiative involving experts in paediatric cell therapy, supportive care and/or study of late effects from cancer and haematopoietic stem cell transplantation was convened to facilitate the comprehensive study of extended CAR T cell-mediated toxicities and establish a framework for new systematic investigations of CAR T cell-related adverse events. Together, this group identified six key focus areas: extended monitoring of neurotoxicity and neurocognitive function, psychosocial considerations, infection and immune reconstitution, other end organ toxicities, evaluation of subsequent neoplasms, and strategies to optimize remission durability. Herein, we present the current understanding, gaps in knowledge and future directions of research addressing these CAR T cell-related outcomes. This systematic framework to study extended toxicities and optimization strategies will facilitate the translation of acquired experience and knowledge for optimal application of CAR T cell therapies.

The results of multicenter phase II, double-blind placebo-controlled trial of maintenance ixazomib after allogeneic hematopoietic cell transplantation (alloHCT) for high-risk multiple myeloma (MM) from the Blood and Marrow Transplant Clinical Trials Network (BMT CTN 1302)

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Background: The role of alloHCT and subsequent maintenance for the treatment of high-risk MM has not been fully defined. We evaluated the efficacy of ixazomib maintenance therapy after alloHCT using reduced intensity fludarabine/melphalan/bortezomib (Flu/Mel/Bort)-based conditioning regimen to treat patients with high risk MM. Methods: This phase 2 prospective multicenter trial (NCT#02440464) enrolled adults 70 years or younger, with either high-risk MM defined by cytogenetics or plasma cell leukemia (PCL) or relapse within 24 months after autologous HCT. Conditioning regimen consisted of Flu/Mel/Bort. Patients received HLA-matched donor unmanipulated peripheral blood grafts. Graft-versus-host disease (GVHD) prophylaxis was tacrolimus plus methotrexate. Between days +60 and +120 after allogeneic HCT, patients were randomly assigned (1:1, stratified by number of prior progressions) to receive ixazomib at 3 mg orally on days 1, 8, 15 on a 28-day cycle or matching placebo for 12 cycles. The study aimed to enroll 138 patients with 110 patients achieving randomization for a progression-free survival (PFS) comparison ixazomib maintenance vs. placebo. Results: Fifty-seven patients from 15 centers were enrolled (2015-18), of whom 52 (91.2%) received allogeneic HCT, and 43 (82.7%) proceeded to randomization (21 assigned to ixazomib and 22 to placebo). Enrollment was delayed by a clinical hold after enrollment of 17 patients due to toxicity concerns related to the conditioning regimen. Remaining patients were enrolled after an amendment reduced bort to a single pre-HCT dose. These and other delays in enrollment led to premature study closure. Median age was 56 (range, 35-65) years, and 33 patients (57.9%) had high-risk MM with 9 patients (15.8%) with primary PCL. At 24 mo post alloHCT, PFS and OS among all alloHCT recipients was 52% and 85% respectively with a corresponding transplant-related mortality (TRM) of 11%. At 21 mo post-randomization, ixazomib vs. placebo groups had similar PFS (55.3% vs. 59.1%) and OS (95% vs. 87%, p = 0.17). Cumulative incidences of grade III-IV acute GVHD at 100 days (9.5% vs. 0%) or chronic GVHD at 12 months (69% vs 64%) were similar. Best response, incidence of progression for ixazomib vs. placebo groups were similar while cumulative incidence of transplant-related mortality (TRM) at 21 months was 0.0% and 4.5% (90%CI: 0.5-16.5%), respectively. Conclusions: AlloHCT with reduced intensity fludarabine/melphalan and a single pre-HCT dose of bortezomib is safe and can produce durable disease control in extremely high-risk patients. ixazomib maintenance after alloHCT could not be assessed as intended due to early termination of study, but there was no signal of an impact in outcomes. Clinical trial information: NCT02440464.

MASS-FIX versus standard methods to predict for PFS and OS among multiple myeloma patients participating on the STAMINA trial

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Background: Measuring response among patients with multiple myeloma is essential for the care of patients. Deeper responses have been associated with better progression free survival (PFS) and overall survival (OS). Serum (SIFE) and urine immunofixation are the currently used markers for biochemical documentation of CR after which marrow is tested for plasma cell clearance. Next generation flow cytometry and sequencing are used to document the presence of minimal residual disease (MRD). Mass spectrometry of blood by MALDI (Mass-Fix) is a new simple, inexpensive, sensitive, and specific means of detecting monoclonal immunoglobulins. To better test the hypothesis that Mass-Fix is superior to existing methodologies to predict for survival outcomes—especially SIFE-- samples from the STAMINA trial (NCT01109004), a trial comparing 3 transplant approaches among patients who have already received induction, were employed. Methods: Five-hundred and seventy-five patients were included. Samples from enrollment post-induction (post-I) and 1-year post enrollment (1YR) were tested when available. Four response parameters were assessed univariately: Mass-Fix, SIFE, complete response, and MRD by next generation flow cytometry. Mass spectrometry spectra were evaluated in a blinded fashion. Complete response was according to the 2006 International Myeloma Working Group criteria. Multivariate Cox proportional hazard models using stepwise regression were developed to explore the independent effect of the different response parameters on PFS and OS and interactions with other risk factors. Results: Of the 4 response measures, only MRD and Mass-Fix predicted for PFS and OS at multiple testing points on multivariate analyses (Table). Of the 4 post-I measurements, only MRD predicted for PFS; however, Mass-Fix was the only post-I measurement to predict for OS. Of all the 1-year measures, both 1YR Mass-Fix and 1YR MRD positivity predicted for inferior PFS and OS. In models including MRD and Mass-Fix, SIFE and CR were not prognostic for PFS or OS. Conclusions: Mass-Fix is a powerful means to track monoclonal proteins. The full utility of Mass-Fix was not exploited given the absence of a diagnostic sample and the fact that only serum (and not urine) was tested. Despite these limitations, it performed well at pre-induction and at 1 year. Mass-Fix provides a convenient and non-invasive means of predicting for myeloma outcomes. Clinical trial information: NCT01109004. [Table: see text]

Real-world evidence of axicabtagene ciloleucel (Axi-cel) for the treatment of large B-cell lymphoma (LBCL) in the United States (US)

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Background: Axi-cel is approved in the US for the treatment of adult patients with relapsed or refractory LBCL after 2 or more lines of systemic therapy. Post-market long term follow up study of commercial Axi-cel recipients using the Center for International Blood and Marrow Transplant Research was recently completed. Methods: From October 2017 to August 2020, 1,500 Axi-cel recipients from 79 centers were enrolled. Of these, 1001 patients with at least 6 months of follow-up were included in this analysis. Outcomes include complete and overall responses rates (CR and ORR), duration of response (DOR), progression-free and overall survival (PFS and OS), cytokine release syndrome (CRS) (Lee D 2014 and American Society for Transplantation and Cellular Therapy [ASTCT]), immune effector cell associated neurotoxicity syndrome (ICANS), hematologic recovery and subsequent neoplasm (SN). Subgroup analysis by sensitivity to therapy, defined as responsive to the last line of therapy prior to Axi-cel. Median follow-up was 12 months (range, 6-28 months). Results: The median age overall was 62 years, 37% were ≥ 65 years, 83% with Eastern Cooperative Oncology Group (ECOG) performance score 0-1, 28% with transformed lymphoma, 14% with high grade lymphoma, 29% with prior autologous transplant, and 66% with chemotherapy-resistant disease prior to Axi-cel. The median time from diagnosis to Axi-cel infusion was 15 months. Best ORR was 70% (CR 53%). Landmark analysis of patients in CR at 6 months post Axi-cel demonstrates a low number of subsequent progression/death events. With respect to outcomes for chemotherapy-sensitive disease versus resistant disease, the ORR, CR, 12-month PFS and OS were 78% vs. 66%, 60% vs. 48%, 55% (95% CI, 48-62%) vs. 40% (95% CI, 37-44%), and 70% (95% CI, 63-76%) vs. 54% (95% CI, 50-58%), respectively. CRS of any grade was reported in 83% of patients. Incidence of Grades ≥ 3 CRS was 10% according to Lee et al 2014, and 13% according to ASTCT Consensus Grading. Median time to any grade CRS was 4 days (range, 1-28 days), and 93% of CRS cases resolved with a median duration of 7 days (range, 1-121 days). ICANS were reported in 576 (57%) patients, grade >3 was 26%. The median time to onset of ICANS was 7 days (range, 1-82 days), and 86% resolved with a median duration of 9 days (range, 1 to 115 days). Twenty-nine patients (2.9%) reported SN: hematologic (N = 17), solid tumors (N = 12). Conclusions: This is the largest report on Axi-cel in the real-world setting and demonstrates consistent efficacy outcomes and further characterizes safety outcomes. Patients in CR at 6 months have sustained disease control with low number of relapse events. Although patients with therapy-sensitive disease experience better outcomes than patients with therapy-resistant, the overall outcomes on both groups of patients are favorable.

Myeloablative versus Reduced-Intensity Conditioning for Hematopoietic Cell Transplantation in Acute Myelogenous Leukemia and Myelodysplastic Syndromes-Long-Term Follow-Up of the BMT CTN 0901 Clinical Trial

Several prospective randomized trials comparing conditioning intensity before allogeneic hematopoietic cell transplantation (HCT) have been performed, with conflicting results. Although reduced-intensity conditioning (RIC) leads to lower treatment-related mortality (TRM), this is offset by higher rates of relapse. Long-term follow-up of randomized comparative trials are limited. Here we present long-term follow-up of a randomized comparison of myeloablative conditioning (MAC) compared with RIC before HCT for acute myelogenous leukemia (AML) or myelodysplasia (MDS). Long-term comparative analyses of overall survival, relapse, and relapse-free survival were performed. Patients age 18 to 65 years with <5% marrow myeloblasts were randomized to receive MAC (n = 135) or RIC (n = 137), followed by HCT from an HLA-matched donor. The primary endpoint of the trial was an 18-month pointwise comparison of overall survival. The analyses were performed using a proportional hazards model. The median follow-up of the entire cohort was 51 months. At 4 years, the transplant-related mortality (TRM) was 25.1% for MAC, compared with 9.9% for RIC (P < .001). Patients who received RIC had a significantly higher risk of relapse compared to those who received MAC (hazard ratio [HR], 4.06; 95% CI, 2.59 to 6.35; P < 0.001). Among the patients who relapsed after HCT, postrelapse survival was similar at 3 years (24% for MAC and 26% for RIC). Overall survival was superior for patients who received MAC compared to those who received RIC (HR, 1.54; 95% CI, 1.07 to 2.2; P = .03). Our data show that patients who received MAC were at higher risk of late TRM compared with those who received RIC; however, because of the exceedingly high rates of relapse in the RIC arm, overall survival remained significantly better for patients who received MAC. Among patients with MDS or AML eligible for either MAC or RIC regimens, long-term follow up demonstrates a survival advantage for patients who received MAC.

Impact of Conditioning Intensity and Genomics on Relapse After Allogeneic Transplantation for Patients With Myelodysplastic Syndrome

PURPOSE

Patients with myelodysplastic syndrome (MDS) are at risk of relapse after allogeneic hematopoietic cell transplantation. The utility of ultra-deep genomic testing to predict and the impact of conditioning intensity to prevent MDS relapse are unknown.

METHODS

Targeted error-corrected DNA sequencing was performed on preconditioning blood samples from patients with MDS (n = 48) from the Blood and Marrow Transplant Clinical Trials Network 0901 phase III randomized clinical trial, which compared outcomes by allogeneic hematopoietic cell transplantation conditioning intensity in adult patients with < 5% marrow myeloblasts and no leukemic myeloblasts in blood on morphological analysis at the time of pretransplant assessment. Clinical end points (53-month median follow-up) included transplant-related mortality (TRM), relapse, relapse-free survival (RFS), and overall survival (OS). Of the 48 patients examined, 14 experienced TRM, 23 are relapse-free, and 11 relapsed, of which 7 died.

RESULTS

Using a previously described set of 10 gene regions, 42% of patients (n = 20) had mutations detectable before random assignment to reduced intensity conditioning (RIC) or myeloablative conditioning (MAC). Testing positive was associated with increased rates of relapse (3-year relapse, 40% v 11%; P = .022) and decreased OS (3-year OS, 55% v 79%, P = .045). In those testing positive, relapse rates were higher (3-year relapse, 75% v 17%; P = .003) and RFS was lower (3-year RFS, 13% v 49%; P = .003) in RIC versus MAC arms. Testing additional genes, including those associated with MDS, did not improve prognostication.

CONCLUSION

This study provides evidence that targeted DNA sequencing in patients with MDS before transplant can identify those with highest post-transplant relapse rates. In those testing positive, random assignment to MAC lowered but did not eliminate relapse risk.

Phase II Trial of Costimulation Blockade With Abatacept for Prevention of Acute GVHD

PURPOSE

Severe (grade 3-4) acute graft-versus-host disease (AGVHD) is a major cause of death after unrelated-donor (URD) hematopoietic cell transplant (HCT), resulting in particularly high mortality after HLA-mismatched transplantation. There are no approved agents for AGVHD prevention, underscoring the critical unmet need for novel therapeutics. ABA2 was a phase II trial to rigorously assess safety, efficacy, and immunologic effects of adding T-cell costimulation blockade with abatacept to calcineurin inhibitor (CNI)/methotrexate (MTX)-based GVHD prophylaxis, to test whether abatacept could decrease AGVHD.

METHODS

ABA2 enrolled adults and children with hematologic malignancies under two strata: a randomized, double-blind, placebo-controlled stratum (8/8-HLA-matched URD), comparing CNI/MTX plus abatacept with CNI/MTX plus placebo, and a single-arm stratum (7/8-HLA-mismatched URD) comparing CNI/MTX plus abatacept versus CNI/MTX CIBMTR controls. The primary end point was day +100 grade 3-4 AGVHD, with day +180 severe-AGVHD-free-survival (SGFS) a key secondary end point. Sample sizes were calculated using a higher type-1 error (0.2) as recommended for phase II trials, and were based on predicting that abatacept would reduce grade 3-4 AGVHD from 20% to 10% (8/8s) and 30% to 10% (7/8s). ABA2 enrolled 142 recipients (8/8s, median follow-up = 716 days) and 43 recipients (7/8s, median follow-up = 708 days).

RESULTS

In 8/8s, grade 3-4 AGVHD was 6.8% (abatacept) versus 14.8% (placebo) (P = .13, hazard ratio = 0.45). SGFS was 93.2% (CNI/MTX plus abatacept) versus 82% (CNI/MTX plus placebo, P = .05). In the smaller 7/8 cohort, grade 3-4 AGVHD was 2.3% (CNI/MTX plus abatacept, intention-to-treat population), which compared favorably with a nonrandomized matched cohort of CNI/MTX (30.2%, P < .001), and the SGFS was better (97.7% v 58.7%, P < .001). Immunologic analysis revealed control of T-cell activation in abatacept-treated patients.

CONCLUSION

Adding abatacept to URD HCT was safe, reduced AGVHD, and improved SGFS. These results suggest that abatacept may substantially improve AGVHD-related transplant outcomes, with a particularly beneficial impact on HLA-mismatched HCT.

Real-World Issues and Potential Solutions in Hematopoietic Cell Transplantation during the COVID-19 Pandemic: Perspectives from the Worldwide Network for Blood and Marrow Transplantation and Center for International Blood and Marrow Transplant Research Health Services and International Studies Committee

The current COVID-19 pandemic, caused by SARS-CoV-2, has impacted many facets of hematopoietic cell transplantation (HCT) in both developed and developing countries. Realizing the challenges as a result of this pandemic affecting the daily practice of the HCT centers and the recognition of the variability in practice worldwide, the Worldwide Network for Blood and Marrow Transplantation (WBMT) and the Center for International Blood and Marrow Transplant Research's (CIBMTR) Health Services and International Studies Committee have jointly produced an expert opinion statement as a general guide to deal with certain aspects of HCT, including diagnostics for SARS-CoV-2 in HCT recipient, pre- and post-HCT management, donor issues, medical tourism, and facilities management. During these crucial times, which may last for months or years, the HCT community must reorganize to proceed with transplantation activity in those patients who urgently require it, albeit with extreme caution. This shared knowledge may be of value to the HCT community in the absence of high-quality evidence-based medicine. © 2020 American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc.

Real-world evidence of tisagenlecleucel for pediatric acute lymphoblastic leukemia and non-Hodgkin lymphoma

Tisagenlecleucel is a CD19 chimeric antigen receptor (CAR) T-cell therapy approved for treatment of pediatric and young adult patients with relapsed/refractory acute lymphoblastic leukemia (ALL) and adults with non-Hodgkin lymphoma (NHL). The initial experience with tisagenlecleucel in a real-world setting from a cellular therapy registry is presented here. As of January 2020, 511 patients were enrolled from 73 centers, and 410 patients had follow-up data reported (ALL, n = 255; NHL, n = 155), with a median follow-up of 13.4 and 11.9 months for ALL and NHL, respectively. Among patients with ALL, the initial complete remission (CR) rate was 85.5%. Twelve-month duration of response (DOR), event-free survival, and overall survival (OS) rates were 60.9%, 52.4%, and 77.2%, respectively. Among adults with NHL, the best overall response rate was 61.8%, including an initial CR rate of 39.5%. Six-month DOR, progression-free survival, and OS rates were 55.3%, 38.7%, and 70.7%, respectively. Grade ≥3 cytokine release syndrome and neurotoxicity were reported in 11.6% and 7.5% of all patients, respectively. Similar outcomes were observed in patients with in-specification and out-of-specification products as a result of viability <80% (range, 61% to 79%). This first report of tisagenlecleucel in the real-world setting demonstrates outcomes with similar efficacy and improved safety compared with those seen in the pivotal trials.