Autologous Transplantation Research Articles

Allogeneic (Allo-SCT) Versus Autologous Stem-Cell Transplantation (Auto-SCT) after Relapse to First Line Auto-SCT in Multiple Myeloma: A Meta-Analysis with Predominantly Individual Patient Data

PFS Introduction A second allogeneic transplantation (allo- SCT) in patients who relapse after first-line autologous transplantation (auto- SCT) is mentioned in a recent statement of the European Society for Blood and Bone Marrow Transplantation (EBMT) as a valuable clinical option, especially when novel immunotherapies such as bispecific antibodies or CAR -T cells are not available. However, it is still unclear whether allo- SCT achieves better results compared to auto-SCT in patients who relapse after first-line treatment with auto-SCT. Objectives To compare progression-free (PFS) and overall survival (OS) between allo-ASCT and auto-ASCT as second-line therapy in patients who relapsed after first-line therapy with auto-SCT by analyzing individual patient data and extracting results from published reports when individual patient data were not available. Methods We searched the electronic databases PubMed, EMBASE, and the Cochrane Library and Up to Date. The search was limited to English-language publications from 1995 to February 2022, and only 6 studies were found that met the requirements for comparing allo SCT and auto- SCT as second-line therapy for patients who had relapsed after the first Auto- SCT. Individual patient data on survival were available for 512 patients from the Japanese Society for Hematopoietic Cell Transplantation registry data (Ikeda T et al. Hematol Oncol 2019) and for PFS and OS for 289 patients from the CIMBMTR registry (Freytes CO et al., BMT 2014). For the other 3 studies, which included 170 patients, data were extracted from the original publications (Mehta J et al, BMT 1998, Qazilbash M et al, Cancer 2006, and Wirk B et al. J Clin Res 2013). We used standard meta-analysis techniques to calculate pooled estimates from random-effects models as incorporated in the software Review Manager V. 5 (The Cochrane Collaboration). Fixed-effect models used as sensitivity analyzes yielded similar results (data not shown). I² = [(Q - df)/Q] X 100%, where Q is the chi² statistic for heterogeneity and df is the degrees of freedom, in order to quantify inconsistency between study outcomes. Results All comparisons of included studies were retrospective in nature, with one study using a cross-case approach (Mehta J et al). Conditioning regimens used for allo-SCT varied between reduced-intensity conditioning (Freytes CO et al and Qazilbash MH et al) and ablative regimens (Mehta J et al). Our analysis was based on individual patient data from 801 patients and data from 170 patients from published reports. No data on PFS were available in the study by Ikeda T et al. The results showed a HR of 1.85 (CI, 1.49-2.22, p < 0.00001) for PFS in favor of the auto-SCT group (Figure 1A). No relevant heterogeneity was observed between reports (Chi² = 3.12, df = 3 (P = 0.37), I² = 3.8%). OS: Similar results were observed for overall survival with a HR of 1.91 (CI, 1.49-2.44, p < 0.00001) in favor of the auto-SCT group at relapse (Figure 1B). The test for heterogeneity showed marked heterogeneity between studies but, similar to PFS, did not reach statistical significance (Chi² = 6.28, df = 4 (P = 0.18), I² = 36.3%). Discussion and Conclusion The included studies showed some heterogeneity but the corresponding test did not reach a significance level. The main reasons for the differences between studies could be different ablative regimens and different patient characteristics. In some studies, the median age was lower in the Allo-SCT group, which favored it, a finding that was not observed in all comparative studies. Allo-SCT appears to benefit only a small proportion of patients with multiple myeloma, whereas graft-versus-host disease and infectious complications affect outcome in a much larger proportion of patients, resulting in a worse prognosis for the entire allo-SCT group. This scenario is supported by our analysis showing a statistically significant advantage of a second auto-SCT over allo-SCT in terms of PFS and OS in patients who relapse after first-line auto-SCT.

Exagamglogene Autotemcel for Severe Sickle Cell Disease

Background: Exagamglogene autotemcel (exa-cel) is a non-viral cell therapy designed to reactivate fetal hemoglobin via ex vivo CRISPR-Cas9 gene-editing of autologous CD34+ hematopoietic stem and progenitor cells (HSPCs) at the erythroid-specific enhancer region of the BCL11A gene in patients (pts) with severe sickle cell disease (SCD). We report that in a pre-specified interim analysis, the pivotal CLIMB SCD-121 trial of exa-cel met primary and key secondary endpoints. Methods: CLIMB SCD-121 is an ongoing, 24-mo, phase 3 trial of exa-cel in pts age 12-35y with SCD and a history of ≥2 VOCs/y in 2y prior to screening. Primary efficacy endpoint is proportion of pts free of severe VOCs for ≥12 consecutive months (mos) (VF12); key secondary efficacy endpoints are proportion of pts free from inpatient hospitalization for severe VOCs for ≥12 consecutive mos (HF12) and proportion of pts free from severe VOCs for ≥9 consecutive mos (VF9). Evaluable pts for VF12 and HF12 had ≥16 mos follow-up after exa-cel infusion; pts evaluable for VF9 had ≥12 mos follow-up after infusion. Evaluation of primary and key secondary endpoints began 60 days after last RBC transfusion for post-transplant support or SCD management. Pts completing trial enrolled in long-term follow-up Study 131. Mean (SD) are shown except where noted. Results: As of 10 Feb 2023, 42 pts with SCD (age 21.2[range 12-34]y; 12[28.6%] age ≥12 to <18y; 4.2 VOCs/y at baseline) received exa-cel. Following infusion, all pts engrafted neutrophils and platelets (median 27 and 34.5 days, respectively). 19/20 (95.0%) pts evaluable for primary endpoint were free of VOCs for ≥12 consecutive mos (VF12; 95% CI, 75.1% to 99.9%; P<0.0001), 20/20 (100%) were free from hospitalizations for VOCs for ≥12 consecutive mos (HF12; 95% CI, 83.2 to 100.0; P<0.0001), and 29/30 (96.7%) were free of VOCs for ≥9 consecutive mos (VF9; 95% CI, 82.8 to 99.9; P<0.0001). In pts achieving VF12, VOC free duration was 21.8 (range 12.3-41.4) mos; 18 pts remained VOC free through follow-up and 1 pt had an adjudicated VOC in the setting of parvovirus infection ~22.8 mos after exa-cel; pt recovered fully and has since been VOC free (Fig). For all pts, total Hb was 12.1 g/dL at Month 3 and was maintained at ≥11.0 g/dL from Month 6 onward; HbF was 36.0% at Month 3 and was generally maintained at ≥ 40.0% from Month 6 onward with pancellular distribution (≥95% RBCs expressing HbF). Proportion of edited BCL11A alleles was stable over time in bone marrow CD34 + and peripheral blood nucleated cells. 36/39 pts with ≥60 days follow-up after last RBC transfusion (including those not yet evaluable) remained VOC free (up to 41.4 mos; Fig). Quality-of-life (QOL) measures showed clinically significant improvements from baseline. All pts had ≥1 adverse event (AE), most were Grade 1 or 2; 40 (95.2%) pts had AEs of Grade 3 or 4 severity. Most common AEs were nausea (66.7%), stomatitis (61.9%), febrile neutropenia (52.4%), headache (52.4%), and vomiting (52.4%). Most AEs and serious AEs (SAEs) occurred within first 6 mos after infusion. No pts had SAEs considered related to exa-cel. As previously reported, 1 pt died from respiratory failure due to COVID-19 unrelated to exa-cel. There were no study discontinuations or malignancies. Conclusions: The CLIMB SCD-121 trial met primary and key secondary endpoints, with exa-cel treatment resulting in early and sustained increases in Hb and HbF leading to elimination of VOCs in 95% of pts, elimination of inpatient hospitalization for VOCs in 100% of pts and improved QOL. Safety profile of exa-cel was generally consistent with myeloablative busulfan conditioning and autologous transplantation. These results show exa-cel has the potential to deliver a one-time functional cure to pts with severe SCD.

Cryopreserved Versus Non-Cryopreserved Peripheral Blood Haematopoietic Stem Cells for Autologous Stem Cell Transplantation in Multiple Myeloma: A Comparative Analysis from the Chronic Malignancies Working Party of EBMT and WBMT

Introduction: Globally, most transplant centres cryopreserve peripheral blood haematopoietic stem cells (PBSC) for use in a subsequent autologous haematopoietic cell transplant (AHCT), utilizing Dimethyl sulfoxide (DMSO) as a cryoprotectant. In contrast, non-vryopreserved PBSC are used in autologous transplants for multiple myeloma (MM) in some countries with more limited resources. We therefor compared standard MM AHCT outcomes between a large transplant centre in Algeria and EBMT registry data. Patients and Methods: This was a retrospective, international, multi-centre, matched-pair analysis between a tertiary transplant center in Algeria and EBMT-affiliated centres in 23 countries. A total of 437 consecutive adult patients undergoing a first MM AHCT in Oran, Algeria, between 2009 and 2020 using non-cryopreserved PBSC. All patients had given informed consent for approved research. PBSC mobilization was performed using G-CSF alone (10µg/kg) for 5 days. Stem cell collection was performed on either the Cobe Spectra or Optia using standard protocols. PBSCs were stored in a 4°C refrigerator immediatly post-collection. PBSC viability was calculated by standard Trypan Blue and flow cytometric techniques. The conditioning regimen was either Melphalan 140 mg/m 2 or 200 mg/m 2. PBSCs were infused 24 hours following Melphalan administration. Patients from Oran were matched to a maximum of 4 patients from an overall cohort of 64,030 patients from 420 EBMT-affiliated centres receiving cryopreserved stem cells over the same time-period. Pair matching was based on the following criteria: (1) patient gender (M,F), (2) MM sub-classification (IgG, IgA, light-chain only), (3) disease status at AHCT (CR, VGPR, PR, relapse/progression), (4) Melphalan conditioning dosage (140 or 200), (5) interval from diagnosis to AHCT, (6) date of AHCT, and (7) age at AHCT. Exact matching was used for the first four variables; propensity score matching was used for the remaining three. Primary endpoints were neutrophil and platelet engraftment as defined by standard EBMT criteria. Secondary endpoints included non-relapse mortality (NRM). The cumulative incidence of neutrophil and platelet engraftment was estimated using the crude cumulative incidence estimator with death was as competing event. The same method was used to estimate NRM as a competing event. Groups were compared using Gray's test. Results: In Oran, 437 MM patients were autografted between 2009 and 2020. Induction regimens (available in 436/437) were heterogeneous (VAD (11.2%), VD (13.3%), CTD (1.4%), VTD (43.1%), VRD (1.4%), VCD (28.0%), TD (0.5%), PAD (0.5%) or others (0.7%)) reflective of local practice. Most patients had one line of induction therapy (n=333 (76.4%); 98 patients (22.5%) had a second line of therapy prior to mobilization. The mean number of collection procedures was two (range (r), 1-3). The average PBSC viability was 95% (r, 93.8-98.5%). Complete matching variable data was available in 405 Oran patients (93%) and 19/405 (4.7%) could not be matched to EBMT patients. These were mostly younger patients (16/19<50 years at AHCT) who received low dose melphalan (17/19 received 140 mg/m 2 melphalan). Of the 386 patients, 357 patients had the required matches of 4 patients from the EBMT database and were used in this analysis. For the patients from Oran, the median dose of PBSCs collected was 3.2x10 6 CD34+ cells/kg (interquartile range (IQR, 2.4-4.5); for EBMT patients (available in 12%), it was 3.7x10 6CD34+ cells/kg (IQR, 2.8-4.9) (p=0.22). Regarding engraftment kinetics, the median times to neutrophil engraftment for the non-cryopreserved and EBMT cryopreserved cohorts were 12 (IQR, 11 to 14) days, and 12 (IQR, 11 to 13) days, respectively (p=0.11). Moreover, no significant difference was evident in the median time to platelet engraftment>20x10 9/L: non-cryopreserved 12 (r, 11 to 14) days and EBMT cryopreserved 12 (r, 11 to 14) (p=0.39) (Figure 1). Non-relapse mortality at day 100 (NRM) rate was 1%(0-2%) in Oran and 1% (1-1%) in EBMT (p=0.4). Conclusion: This large co-operative study between Oran and EBMT found that neutrophil and platelet engraftment rates were similar in the cryopreserved and non-cryopreserved matched cohorts. Moreover, there was no difference in NRM. The use of non-cryopreserved PBSC for MM AHCT in countries with limited resources is more straighforward and less costly.

Results of an Italian Retrospective Clinical Experience on Mediastinal Gray Zone Lymphoma

Introduction and methods: Mediastinal gray zone lymphoma (GZL) emerged as a rare and challenging entity due to its high rate of pathological reclassification and heterogeneous clinical management. The bio-GZL2020 study was designed to centralize histological samples and clinical data of patients (pts) diagnosed with GZL between 2006 and 2020 in 16 Italian hematological centers. We here report the preliminary clinical results of this retrospective analysis. Results: Overall, we collected samples and clinical data of 68 pts with GZL. According to the 2022 WHO and ICC classifications we excluded nine pts for lacking mediastinal involvement, hence 59 pts were analyzed. Pts were mostly stage I-II (62.7%); 57.6% had a mediastinal bulky disease. The site of diagnostic biopsy was the mediastinum in 29 pts. Additional clinical characteristics at baseline are reported in Table 1. One patient died before the start of treatment and was excluded from survival analysis. First line chemotherapy (CHT) consisted in DA-EPOCH in 31 pts, CHOP-like regimens in 17 pts, ABVD in six pts, MACOP-B in three pts and DHAP in only one case. Eight pts did not receive rituximab with CHT (six ABVD pts, two CHOP-like pts). Dose escalation in R-DA-EPOCH was performed in 75% of pts, with 18 pts (64.3%) attaining level 3 or higher. Four advanced stage, high-risk pts received central nervous system prophylaxis. Twenty-two pts performed an interim PET-scan during first line therapy; data on Deauville score was available in 19 cases, with 9 pts obtaining a score 1-3. Restaging after first line CHT showed 37 pts in complete remission (CR; 63.8%), nine pts in partial remission (PR; 15.5%), five pts in stable disease (SD; 8.6%) and seven pts in progressive disease (PD; 12.1%). Thirty-one pts (53.4%) received a consolidative treatment (26 pts radiotherapy (RT) only, seven pts autologous transplant (ASCT) only, two pts both RT and ASCT). Restaging after first line consolidation showed 43 CR (74.1%), four PR (6.9%), two SD (5.2%) and eight PD (13.8%). Nineteen pts underwent a second line CHT, 16 of them with a platinum-based regimen; brentuximab vedotin, BeGEV and HyperCVAD were used in one patient each. Second line consolidation ASCT was performed in seven pts, while one received an allogeneic transplant. Of the 17 restaged pts after second line CHT seven were in CR, 10 were not responsive (four SD, six PD). Considering all salvage lines five pts received a checkpoint inhibitor, nine underwent brentuximab vedotin treatment. Overall survival (OS) was 86.9% at 5 years and 71.3% at 10 years; beta2-microglobulin (available only in 32 pts) and the response after first line therapy were associated to a statistically significant difference in OS in univariate analysis. Progression-free survival (PFS) was 61.9% at 5 and 10 years. The use of rituximab, the Deauville score 1-3 at interim PET during induction, and the response after first line therapy were associated to a statistically significant difference in PFS in univariate analysis. ABVD was associated to poorer results in terms of OS and PFS although no significant difference was observed. No statistically significant difference in term of PFS was observed between pts treated with intensified regimens (DA-EPOCH, MACOP-B, DHAP) and other treatments in first line. Excluding pts directly shifted to salvage therapy, consolidative RT after first line CHT showed no statistically significance in term of both OS and PFS. Conclusions: To our knowledge our study represents the largest retrospective data collection on GZL among hematological Italian centers. This preliminary analysis did not show a clear advantage of intensive therapies such as DA-EPOCH or MACOPB, while the positive prognostic role of rituximab was confirmed in PFS. The prognostic role of interim PET-CT scan seems interesting and should be evaluated in subsequent trials. Further refinement of the reported results is expected in relation of an ongoing central pathological review by a panel of expert hematopathologists.

A Highly Successful Model to Decrease Racial Disparities and Increase Access to Autologous Transplants Among African Americans with Multiple Myeloma - Outreach and Satellite Transplant Clinics

Background It is well known that racial disparities exist between White and African Americans (AA) with multiple myeloma (MM) resulting in an inferior outcome among AA. It is believed that the disparities are due to socioeconomic barriers that limit access to timely, appropriate and high quality medical care. A Veterans Administration study of MM patients showed that with equal access, AA have superior survival compared to Whites. Autologous hematopoietic stem cell transplant (AHST) is a standard treatment for MM and improves survival but only 20% of AA receive AHST compared to 39% for Whites. Possible obstacles for AA are lack of resources such as transportation, financial and family/care giver support to travel to a distant transplant center. There is extensive awareness and data regarding racial disparities in MM and recommendations for improvement. We present our experience to bring to attention a simple intervention to decrease the disparities in this retrospective IRB approved study. Methods At the Medical College of Georgia, Augusta University, Georgia, we embarked on a program of outreach beginning July 2017 to market our transplant and hematologic malignancy program with the intention of increasing patient referrals and transplant volumes. The health system and marketing/outreach program collaborated with our cancer center and provided resources to execute the project. This included personally traveling as a group and visiting community practices that were between 1 to 200 miles in our catchment area, meeting physicians, advanced practice providers (APPs), nurses, referral coordinators to apprise them of our services. The services included access to transplant faculty mobile numbers, a simple “ONE CALL ONLY” referral system and a meticulous line of communication. Beginning in early 2019, we started satellite clinics in two large community practices; practice A 65 miles and practice B 89 miles from our center. One transplant physician traveled to practice A and a second one to practice B once a month where patients with hematologic malignancies were evaluated for a consultation. Patients that required a transplant received induction treatment, pre-transplant work up including MM lab testing, organ function evaluation, scans, bone marrow exams at the satellite clinics to minimize travel and make it easier for patients and families. The transplant procedure itself including stem cell collection, conditioning regimen, stem cell reinfusion and recovery during myelo-suppression was performed at our transplant center. Upon discharge from the hospital, the subsequent post-transplant care was transitioned as early as possible back to the satellite clinics. This consisted of post-transplant discharge monitoring, restaging work up required such as MM blood work, scans and bone marrow evaluation. Recommendations regarding consolidation/maintenance treatment were made during one of the monthly transplant physician's satellite clinic visits but administered by the community oncologists. In this analysis, we only included patients with MM who received a transplant. Results Between 2013 and June, 2017 (no outreach and no satellite clinics) our transplant center did 81 MM transplants and 292 from July 2017 to July 2023. Before starting outreach and satellite clinics there were 3 transplants from practice A and 0 from practice B. From July 2017 to July 2023 (post outreach and satellite clinics) there were 64 transplants; 46 from practice A and 18 from practice B. The median age was 65.9 at time of transplant and 34 were male. The racial breakdown was 39 AA (60.9%) and 37.5% White. The median distance from the patients' homes to practice A and B was 16.9 and 34.8 miles and to the transplant center 85.7 and 99.25 miles respectively. 25 patients had Medicare and 39 private insurance. Conclusion We conclude that outreach, and personal and meticulous communication increases MM transplant referrals. Most importantly, setting up satellite clinics is an effective initiative and will not only increase transplant referrals, but most notably increases AHST access to AA. We think this is due to improving patient convenience by decreasing the number of visits to a distant transplant center, travel time and burden to care givers so the AA can be cared for closer to home. We believe that this is a simple yet very practical and effective way of decreasing disparities and making AHST more accessible to African Americans.

RAMP up: Risk Adapted Post-Autologous Transplant Maintenance Therapy in MRD Positive Myeloma Patients

Background. Post-autologous stem cell transplant (ASCT) maintenance therapy for patients with newly diagnosed multiple myeloma (MM) continues to evolve. Currently, single agent lenalidomide maintenance remains standard of care but outcomes for patients with high-risk cytogenetics are inferior to those with standard risk disease; optimal maintenance strategies for these patients need to be developed. Minimal residual disease (MRD) has proven to be a powerful prognostic factor for PFS and OS but is not yet used to guide treatment. Isatuximab is a cytolytic CD38-directed, immunoglobulin G1 (IgG1) chimeric monoclonal antibody FDA-approved for the treatment of relapsed or refractory MM that is overall well tolerated and efficacious when used in combination regimens. Our upcoming trial, RAMP UP (NCT05344833), investigates the safety and efficacy of isatuximab combined with lenalidomide as a maintenance regimen in patients who are MRD-positive after autologous transplant. Study Design and Methods. This prospective, multicenter single-arm phase 2 (Figure 1) trial will enroll patients that are MRD-positive (10 -5) by Adaptive next generation sequencing within 90 days (+/- 30 days) post-autologous transplant. We plan to enroll: R-ISS stage 1, 2 or 3; <2 lines of induction therapy prior to transplant; > PR per IMWG criteria post-transplant; and ECOG Performance Status <2. Patients will be treated with isatuximab (10 mg/kg weekly for cycle 1 and every other week thereafter) and lenalidomide (10 mg daily on days 1-21) on 28-day cycles for a total of 3 years. Patients will be monitored for disease response every 3 months and for marrow MRD every 12 months. The primary endpoint is the 1-year rate of CR/MRD negativity (10 -5); secondary endpoints include 1-year rate of CR/MRD negativity (10 -6), IMWG-defined response rates, 3-year overall CR/MRD-negativity, PFS, OS, treatment-related adverse events, and health related quality of life (HRQoL) measured by EORTC-QLQ-C30, EQ-5D-5L, EORTC QLQ-MY20. We propose enrollment of 50 patients to allow for approximately 10% dropout rate in order to have 43 patients analyzed for the primary endpoint; for 50 patients to be treated, we estimate that 75-100 patients may have to be enrolled. Correlative objectives include correlation of isatuximab pharmacokinetics and receptor occupancy with MRD-negative response and time to progression, characterization of differences in the BM and peripheral blood T, B, and myeloid cell compartments using cellular indexing of transcriptomes and epitopes (CITE-Seq) between responders and nonresponders, and concurrent assessment of other disease biomarkers, including peripheral blood circulating multiple myeloma cells (CELLSEARCH), with MRD testing. Discussion. Our study started June 2023. One patient has been enrolled, and two have signed informed consent for enrollment. Ultimately, our study aims to inform MRD risk-adapted approaches for maintenance therapy in myeloma.

A Universal CRISPR/Cas9n-Mediated Genome Editing Approach for ELANE-Related Severe Congenital Neutropenia

Severe congenital neutropenia (CN) is an inherited bone marrow failure syndrome characterized by impaired maturation of neutrophil granulocytes. Due to the lack or very low levels of neutrophils in the peripheral blood, patients experience severe, life-threatening bacterial infections as early as birth. Autosomal-dominant ELANE mutations are the most common cause of CN. Although most patients respond to daily treatment with recombinant human granulocyte colony-stimulating factor, about 15% of patients do not respond to this cytokine, and approximately 20% of patients develop myelodysplasia or acute myeloid leukemia. The only curative treatment available thus far is allogenic hematopoietic stem cell transplantation, which is associated with serious side effects. Autologous transplantation of gene-edited patients' HSPCs offers a novel curative therapy. Considering the wide range of mutations distributed throughout the ELANE gene, A universal, high-safety-profile approach could be advantageous for all ELANE-CN patients. Our group has already published a universal CRISPR/Cas9-mediated knockout approach for the ELANE gene; however, targeting the coding sequence region (CDS) of the ELANE gene could lead to the introduction of new disease-causing variants, so it may be harmful for patients. In order to address this concern, we reformatted our previously published knockout concept into a clinical-grade gene therapy strategy. We have screened cis-regulatory regions in the ELANE core promoter and, using CRISPR/Cas9n, introduced two nicks on opposing strands of the Goldberg-Hognes box region (TATA-box) to make the transcription starting process inefficient, as transcription factors and RNApol II cannot recognize the modified sequence. Theproposed strategy targets the non-coding region of the ELANE gene and thus does not generate new unwanted variants. Also, by replacing Cas9 with Cas9-ncikase, the off-target activity should decrease by up to 1000-fold. We have observed a markedly elevated neutrophil differentiation in gene-edited ELANE-CN patients HSPCs (n = 2), as assessed by the percentage of CD45 +CD11b +CD15 +, CD45 +CD15 +CD16 +, and CD45 +CD16 +CD66b + myeloid/granulocytic cells, compared to the mock electroporated ELANE-CN group, while no disruption of granulopoiesis in healthy donor HSPCs (n = 2) was detected. Results validated by the CFU assay. To have nucleotide-level resolution of on-target events, we performed targeted next-generation sequencing of edited loci on gene-edited healthy donors and ELANE-CN HSPCs. Next-generation sequencing results showed >90% on-target efficiency. CRISPR/Cas9n-mediated targeting of the TATA box rescued defective granulopoiesis in vivo, as gene-edited ELANE-CN HSPCs (n = 3) were transplanted in NSG mice and assessed by the percentage of neutrophils (hCD19 -hCD3 -hCD66b Int/lowhCD33 +hCD16 high) after 16 weeks. We have also observed efficient engraftment and preserved the multilineage potential of gene edited HSPCs in immunodeficient NSG mice. The strategy also depicted a safe profile upon applying gene editing to healthy donor CD34 + HSPCs and performing GUIDE-seq and CAST-seq. GUIDE-seq highlighted two potential off-target sites after >=6 mismatches, while no chromosomal translocations were detected by CAST-seq. RNA-sequencing of in vitro-generated neutrophils from gene-edited HSPCs of healthy donors (n = 2) confirmed a >9-fold reduction of ELANE gene expression level. Important to note, none of the other serine proteases or neighboring genes were down-regulated. Taken together, ex vivo CRISPR-Cas9n-based gene editing of ELANE's gene promoter in the setting of autologous stem cell transplantation could be a safe therapeutic approach for all ELANE-CN patients.

Survival Patterns of Non-Randomized Patients in the IELSG37 Study: Deauville Score 4 Is Not Necessarily Associated with Poor Outcome in Primary Mediastinal Lymphoma

Background:Primary mediastinal B-cell lymphoma (PMBCL) is clinically and biologically distinct from other types of aggressive lymphoma, it is characterized by a bulky mediastinal mass and most commonly occurs in women between 30 and 40 years of age. Although consolidation radiotherapy (RT) has yielded extremely positive outcomes in PMBCL, it carries a higher risk of long-term complications. Consequently, there has been an ongoing debate regarding the necessity of RT in patients responding to frontline immunochemotherapy. Methods:In the IELSG37 study, PMBCL 530 patients were treated with rituximab- and doxorubicin-containing regimens; 98% had stage I-II. Their response was assessed by positron emission computed tomography (PET/CT); 268 achieved a complete metabolic remission (CMR) defined as Deauville score (DS) 1 to 3 according to the Lugano classification and were randomly allocated to observation or mediastinal RT. The primary analysis [Zucca et al. J Clin Oncol 2023; 41 (suppl 17): abs. LBA7505] has shown that patients in CMR can safely forgo RT. The 3-year overall survival (OS) rate was 99% irrespective of irradiation. RT provided only minimal benefit on progression-free survival (PFS), which was over 96% at 3 years in both arms. Here we present the outcome of the 262 patients who were not randomized and were managed according to the preference of their treating physician. Results:Median follow-up was 64 months (interquartile range [IQR], 49-69). Besides 230 patients failing frontline treatment (174 DS4 and 56 DS5), the non-randomized cohort also included 1 patient with DS2 (who refused randomization and received RT) and 31 patients with DS3 who were initially considered as partial responders before a protocol amendment that changed the definition of CMR from DS 1-2 to DS 1-3. Among these non-randomized patients with DS3, 27 had RT consolidation, 1 was only observed, 2 had salvage chemotherapy ± RT, and 1 had missing data due to consent withdrawal; their 3-year PFS was very close to the one of the randomized patients with DS3 (90 vs 92%, p=0.99). In the DS4 group, 12 patients were observed, 149 had only RT, and 13 had second-line chemotherapy, with (12) or without (1) autologous stem cell rescue, 8 of 13 also had RT. Among the patients with DS5, only 2 were observed, 32 had only RT, and 22 had second-line chemotherapy, with (15) or without (7) autologous stem cell rescue; 12 of them also had RT. The outcome of patients with DS4 was overlapping the one of the patients achieving a CMR, with 3-year PFS of 97.1% (95%CI 93-99) and 97.4% (95%CI 95-99), respectively, while patients with DS5 had a significantly poorer 3-year PFS (62.4%, 95%CI 48-74) [Figure1A]. The 3-year OS showed a similar trend (98% in patients with DS4, 99% in those randomized, and 78% in the DS5 group). Notably, compared to patients receiving consolidation RT alone or only observed, the residual lesions on post-immunochemotherapy PET/CT scans of patients with DS4 and DS5 who were treated more aggressively (with salvage chemotherapy ± autologous transplant and/or RT) displayed significantly higher tracer maximum standardized uptake value (SUVmax, median: 8.2, IQR 4.6-16.5 vs. 3.8, IQR 3.1-4.9; p<0.0001) and larger residual metabolic tumor volume (MTV, median: 18 ml, IQR 3-95 vs. 3.6, ml, IQR 1-10; p<0.0001). These patients had significantly worse outcomes compared to those who received consolidation RT or were observed only [Figure 1B]. Conclusions:Patients with DS4 had outcomes similar to those of patients achieving a CMR, indicating that this group may either include a significant number of “false-positive” cases with inflammatory uptake or that their residual disease is limited and can potentially be cured with consolidation RT. Patients with DS5 had a significantly poorer outcome, although nearly half of them did well with RT alone. It seems plausible that clinical condition of the patient and/or imaging features of the residual disease have influenced treatment choices in patients without CMR after frontline immunochemotherapy. Further studies are needed to investigate whether PET metrics and/or liquid biopsies can aid in personalizing treatment and identifying patients who could potentially avoid irradiation.

Autologous Transplant (auto-HCT) Is Associated with Improved Clinical Outcomes Compared to CAR-T Therapy in Patients (pts) with Large B-Cell Lymphoma (LBCL) Achieving a Complete Remission

Introduction: CAR-T therapy is the standard of care for pts with relapsed LBCL as early as in the second line in those with early relapse or with primary refractory disease. In practice, pts who are intended to receive CAR-T, commonly require interim therapy before leukapheresis, wherein a small fraction may achieve a complete remission (CR). Having chemosensitive disease, these pts can be considered for auto-HCT. Also, there are reports indicating the efficacy of CAR-T therapy in CR pts (Strati et al., Haematologica, 2023; Wudhikarn et al., Blood Adv, 2022). We compared the outcome of pts with LBCL who received CAR-T vs. auto-HCT while in a CR. Methods: Pts aged 18-75 years with DLBCL or primary mediastinal lymphoma who received CAR-T (between 2018-2021) or auto-HCT (between 2015-2021) while in a CR by PET or CT were included in this analysis using the data from the Center for International Blood & Marrow Transplant Research (CIBMTR) registry. Primary endpoints included progression-free survival (PFS) and overall survival (OS). Treatment-related mortality (TRM) and relapse rate were among the secondary endpoints. Results: We identified 360 pts with LBCL who were in a CR before receiving CAR-T (n=79, tisa-cel 53%, axi-cel 46%, and liso-cel 1%) or auto-HCT (n=281). Median follow-up was 24.7 months (range 3.3-49.4) for the CAR-T cohort and 49.7 months (range 3.0-95.4) for the auto-HCT cohort. Selected baseline characteristics are shown in Table 1. CRs were confirmed by PET scan in 90% of CAR-T pts and 99.6% of auto-CAR-T pts (p < 0.01). The most common lymphodepletion regimen for CAR-T was Cy/Flu (82.3%) and the most common conditioning regimen for auto-HCT was BEAM (77.6%). Thirty-seven (13.2%) of auto-HCT pts had a later CAR-T but no pts from the CAR-T cohort had subsequent auto-HCT. In univariate analysis, treatment with CAR-T was associated with a higher rate of relapse at 2 years (48% vs. 27.8%; p < 0.001), a lower rate of 2-year PFS (47.8% vs. 66.2%; p < 0.001) and lower 2-year OS (65.6% vs. 78.9%; p=0.037). There was no difference in rates of 2-year TRM (4.1% vs. 5.9%; p=0.673). Similarly, focusing on patients with early (12 months) treatment failure (CAR-T =57 and auto-HCT=163), treatment with CAR-T was associated with a higher 2-year relapse rate (45.9% vs. 22.8%; p <0.001) and an inferior 2-year PFS (48.3% vs.70.9%.; p <0.001) compared to auto-HCT (figure-2) while there was no difference in 2-year OS or TRM. In the multivariable analysis of outcomes, treatment with CAR-T was associated with higher risk of relapse (HR 2.18; p < 0.0001) and an inferior PFS (HR 1.83; p=0.0011) compared to auto-HCT. There was no difference in the risk of TRM (HR 0.59; p=0.36) or OS (HR 1.44; p=0.12). Conclusions: In pts with relapsed LBCL who achieve a CR, treatment with auto-HCT is associated with a lower relapse rate and an improved PFS compared to CAR-T, including in pts with early treatment failure (within 12 months). These results are in line with previously reported improved clinical outcomes with auto-HCT compared to CAR-T in pts in partial remission (Shadman et al. Blood, 2022). The data support utilization of auto-HCT in pts with relapsed LBCL achieving a CR.

Exagamglogene Autotemcel for Transfusion-Dependent β-Thalassemia

Background: Exagamglogene autotemcel (exa-cel) is a non-viral cell therapy designed to reactivate fetal hemoglobin (HbF) via ex vivo CRISPR-Cas9 gene-editing of autologous CD34+ hematopoietic stem and progenitor cells (HSPCs) at the erythroid-specific enhancer region of BCL11A in patients (pts) with transfusion-dependent β-thalassemia (TDT). Here we report that in a pre-specified interim analysis, the pivotal CLIMB THAL-111 trial of exa-cel met primary and key secondary endpoints. Methods: CLIMB THAL-111 is an ongoing, 24-month (mo), phase 3 trial of exa-cel in pts age 12-35y with TDT and a history of ≥100 mL/kg/y or ≥10 U/y packed red blood cell (RBC) transfusions in the 2y before screening. Primary endpoint is transfusion independence defined as proportion of pts maintaining a weighted average hemoglobin (Hb) ≥9 g/dL without RBC transfusion for ≥12 consecutive mos (TI12). Key secondary endpoint is proportion of pts maintaining a weighted average Hb ≥9 g/dL without RBC transfusion for ≥6 consecutive mos (TI6). Evaluable pts had ≥16 mos of follow-up after exa-cel infusion. Evaluation of TI12 and TI6 started 60 days after last RBC transfusion for post-transplant support or TDT management. Pts completing trial enrolled in long-term follow-up Study 131. Mean (SD) shown except where noted. Results: As of 16 Jan 2023, 52 pts (mean age 21.5[range 12-35]y; 18[34.6%] age ≥12 to <18y; 31[59.6%] with severe genotypes [β 0/β 0 or β 0/β 0-like], median annualized transfusion volume 201.0 mL/kg) received exa-cel; median follow-up 20.4 (range 2.1-48.1) mos. Following infusion, all pts engrafted neutrophils and platelets (median 29 and 44 days, respectively). Of the 35 pts evaluable for primary and key secondary endpoints, 32 (91.4%) achieved TI12 and TI6 (95% CI: 76.9%, 98.2%; P<0.0001). Pts achieving TI12 stopped transfusions 35.2 (SD, 18.5) days after exa-cel infusion and remained transfusion independent for 22.5 (range, 13.3, 45.1) mos (Fig). For 3 pts not achieving TI12, one had reductions in annualized RBC transfusion volume of 83.9%, while the others have been transfusion-free for 7.3 mos and 4.0 mos starting 60 days after the last transfusion. For all pts, total Hb was 11.4 g/dL at Month 3 (≥12g/dL Month 6 onward) and HbF was 7.7 g/dL at Month 3 (≥ 10 g/dL Month 6 onward) with pancellular distribution (≥95% RBCs expressing HbF Month 6 onward). Proportion of edited BCL11A alleles was stable over time in bone marrow CD34 + and peripheral blood nucleated cells. Pts not yet evaluable and with sufficient follow-up were also transfusion-free. Quality-of-life (QOL) measures showed clinically significant improvements. All pts had ≥1 adverse event (AE), most were Grade 1 or 2; 46 (88.5%) pts had AEs of Grade 3 or 4 severity. Most common AEs were febrile neutropenia (61.5%), headache (53.8%), and stomatitis (50.0%). Most AEs and serious AEs (SAEs) occurred within first 6 mos after infusion. Two pts had SAEs considered related to exa-cel: headache, hemophagocytic lymphohistiocytosis (HLH), acute respiratory distress syndrome and idiopathic pneumonia syndrome (latter also considered related to busulfan) all in the context of HLH (n=1) and delayed engraftment and thrombocytopenia (both also considered related to busulfan) (n=1), which all resolved. There were no deaths, discontinuations, or malignancies. Conclusions: The CLIMB THAL-111 trial met primary and key secondary endpoints, with exa-cel treatment resulting in early and sustained increases in Hb and HbF leading to transfusion independence in >90% of pts with TDT and improved QOL. Safety profile of exa-cel was generally consistent with myeloablative busulfan conditioning and autologous transplantation. These results show exa-cel has the potential to deliver a one-time functional cure to pts with TDT.

Oncology Care at Home: A Patient-Centered Approach to Managing Care for Bone Marrow Transplant and CAR-T Cell Therapy Patients

Introduction. More than half of patients with cancer who receive cytotoxic chemotherapy and/or immunotherapies experience deleterious side effects such as febrile neutropenia, infection, neurotoxicity, and cytokine release syndrome. Early intervention and treatment for these side effects can help avoid complications and improve outcomes, but delays in treatment administration are common as most outpatient management approaches depend on patient self-assessment and patient-initiated pursuit of follow-up care. Remote patient monitoring through digital health technologies offers the opportunity to bridge this gap without imposing undue burden on either patients or healthcare providers. This feasibility study assessed the results of a technology-assisted in-home oncology care program to remotely monitor bone marrow transplant and CAR T-cell therapy patients and provide early intervention for symptomatic episodes needing clinical management. The program also offered support for patients to obtain routine lab draws, hydration, antiemetics, intravenous antibiotics, and a provider assessment at home. Technical and operational feasibility were evaluated together with perceived user experience among patients, caregivers, and providers. Methods. Ten patients between 18-89 years old participated in the study for up to 90 days following allogeneic bone marrow transplant and up to 30 days following CAR T-cell therapy or autologous bone marrow transplant. Patients used continuous-wear biometric sensors for passive vital sign monitoring around the clock seven days per week and engaged with a chatbot by SMS text for health status checks and symptom reporting. Scheduled home care was administered by licensed home health providers. Virtual care center personnel evaluated patient status based on wearable data and patient messaging and followed up directly with patients or engaged patients' treating clinicians for notification and management of urgent issues as needed. Patients and caregivers were asked to complete surveys about their experience with and perceptions of the program at midpoint and study completion, while providers were asked to complete end-of-study surveys to capture their perspectives across all patients. Patients were also asked to participate in brief interviews at study midpoint and at the end of the study. Interim Results. Eighty percent of patients participated in the program as intended through wearing devices and responding to engagement prompts. Wearable sensors detected a total of 184 outpatient alerts from patients between April and July 2023, of which 57 led to follow up with patients, 12 required further follow up with the clinical care team, and 5 required follow up care in a clinical setting due to elevated temperature or respiratory rate. Sixty percent of patients responded more than 50% of the time to requested health assessment surveys. Patient engagement with the chatbot and symptom reporting system led to 48 events needing virtual care team follow up, of which 20 were to answer patient questions and 28 were in response to reports of concerning symptoms. A total of 11 events were further referred by the virtual care team to the clinical care team, of which 5 required follow up care in a clinical setting. Study data collection will complete in August 2023. Initial Conclusions. Technology-assisted remote patient monitoring is feasible for use with bone marrow transplant and CAR T-cell therapy patients at home. Successful integration with clinical practice settings requires tailoring to existing workflows. Further assessment of patient acceptance for short-term versus long-term monitoring is recommended.

Results of the Phase III Randomized Iskia Trial: Isatuximab-Carfilzomib-Lenalidomide-Dexamethasone Vs Carfilzomib-Lenalidomide-Dexamethasone As Pre-Transplant Induction and Post-Transplant Consolidation in Newly Diagnosed Multiple Myeloma Patients

Background. The current standard treatment for transplant-eligible (TE) patients (pts) with newly diagnosed multiple myeloma (NDMM) consists of quadruplet induction with proteasome inhibitors, immunomodulatory agents, dexamethasone and anti-CD38 monoclonal antibody followed by high-dose melphalan and autologous stem-cell transplant (MEL200-ASCT), with subsequent consolidation. The phase III IsKia trial assessed efficacy and safety of isatuximab-carfilzomib-lenalidomide-dexamethasone (IsaKRd) as pre-ASCT induction and post-ASCT consolidation vs KRd. Methods. TE NDMM pts aged <70 years were enrolled and randomized. IsaKRd pts received 4 28-day cycles of Isa: 10 mg/kg IV days 1, 8, 15, 22 cycle 1, followed by 10 mg/kg days 1, 15 cycles 2-4; K: 20 mg/m 2 IV day 1 cycle 1, followed by 56 mg/m 2 IV days 8, 15 cycle 1 and days 1, 8, 15 cycles 2-4; R: 25 mg PO daily days 1-21; d: 40 mg PO days 1, 8, 15, 22; MEL200-ASCT and 4 consolidation cycles with IsaKRd at the same schedule. KRd pts received 4 KRd induction cycles; MEL200-ASCT and 4 KRd consolidation cycles (K, R and d at the same schedule as in the IsaKRd arm). The primary endpoint was the rate of minimal residual disease (MRD) negativity by next-generation sequencing (NGS; 10 -5) after consolidation in the intention-to-treat (ITT) population. MRD was tested in all pts who achieved at least a very good partial response (≥VGPR). Key secondary endpoints were the rate of NGS MRD negativity (10 -5) after induction and PFS. MRD rates were evaluated in an ITT analysis (pts with missing MRD data or who achieved ≤PR were considered as MRD positive). The data cut-off for the analysis was May 22, 2023. Results. 302 pts were enrolled and randomized (151 in both the IsaKRd and KRd arms). Pt characteristics were well balanced between the two arms: median age was 61 vs 60 years, respectively; 18% vs 19% of pts had high-risk (HiR) cytogenetic abnormalities (CA) [del(17p) and/or t(4;14) and/or t(14;16)]; 9% vs 8% had ≥2 HiR CA [double hit; including del(17p), t(4;14), t(14;16) and gain/amp(1q)]. In ITT analysis, the rates of MRD negativity at the 10 -5 cut-off after consolidation (primary endpoint) were 77% vs 67% (OR 1.67; p=0.049) with IsaKRd vs KRd; the respective rates of MRD negativity at the 10 -6 cut-off were 67% vs 48% (OR 2.29; p<0.001); consistent MRD results were detected by next-generation flow. ≥VGPR after consolidation was 94% in both arms; ≥CR 74% vs 72% and sCR 64% vs 67% in the IsaKRd vs KRd arms. The MRD negativity advantage, both at 10 -5 and 10 -6, was retained in all subgroups analyzed ( Figure), with similar benefit in pts with standard-risk (SR) and HiR features. In particular, the 10 -5 MRD negativity rates with IsaKRd were 76% in HiR and 77% in double-hit pts, comparable to the one in SR pts (79%). In the KRd arm, the 10 -5 MRD negativity rates were 58% in HiR and 53% in double-hit pts, inferior to the one in SR pts (70%). The 10 -6 MRD negativity rates with IsaKRd were 72% in HiR, 77% in double-hit pts and 67% in SR pts. The MRD negativity rate after induction (first key secondary endpoint) was also significantly higher with IsaKRd vs KRd (10 -5: 45% vs 26%, OR 2.34, p<0.001; 10 -6: 27% vs 14%, OR 2.36, p=0.004), with a consistent benefit in all subgroups. After induction, the MRD negativity rates in HiR and double-hit pts treated with IsaKRd were: 10 -5, HiR 60%, double-hit 54%; 10 -6, HiR 40%, double-hit 31%. The MRD negativity rates after ASCT were also significantly better with IsaKRd vs KRd (10 -5: 64% vs 49%, OR 1.93, p=0.006; 10 -6: 52% vs 27%, OR 3.01, p<0.001), with a consistent advantage in all subgroups. At the current follow-up (median, 20 months, IQR 18-23), there was no difference in PFS (95% at 1 year in both arms). 55% of pts had ≥1 hematologic adverse events (AEs) with IsaKRd vs 43% with KRd; main grade 3-4 hematologic AEs in IsaKRd vs KRd were neutropenia (37% vs 22%) and thrombocytopenia (15% vs 17%). 41% of pts had ≥1 non-hematologic AEs with IsaKRd vs 37% with KRd, including infections (16% vs 12%), gastrointestinal (7% vs 5%), vascular (2% vs 7%) and cardiac events (1% vs 4%). Discontinuation for toxicity was 6% in IsaKRd vs 5% in KRd arms; treatment-related deaths were 4 with IsaKRd (2 COVID, 1 pneumonia, 1 pulmonary embolism) and 1 with KRd (septic shock). Conclusion. In TE NDMM pts, the addition of isatuximab to KRd induction and consolidation significantly increased MRD negativity rates in every treatment phase as compared to KRd, with no new safety concerns. This benefit was retained in HiR pts.

Melphalan-Induced Multiple Myeloma Cells Exhibit a Senescent-like Dormant Phenotype

Multiple myeloma (MM) is an incurable plasma cell malignancy. Despite therapeutic advances that have vastly improved survival, all patients are expected to relapse. One mechanism that may contribute to MM relapse is tumor dormancy. Dormant MM cells may persist in the bone marrow, where they exhibit reduced proliferative capacity and resistance to treatment. These cells may then exit dormancy following treatment to drive disease relapse. Dormancy shares many features with cellular senescence, a state of stable growth arrest induced by cell stress. Chemotherapies that produce genotoxic stress have been associated with therapy-induced senescence (TIS). One such genotoxic agent, melphalan (Mel), is routinely administered to MM patients for myeloablation prior to autologous bone marrow transplant. We hypothesized that High Dose Mel (HDM) induces a senescent-like dormant phenotype in surviving MM cells. To test our hypothesis, we developed an in vitro model for HDM. We identified 10µM Mel as a concentration to induce >90% cell toxicity (HDM) in 5TGM1 mouse MM cells over 10 days. 5TGM1-GFP MM cells were cultured with HDM or vehicle (Veh) for 6 hours; cells were then cultured in normal growth medium in the presence of primary mouse (C57BL/6) bone marrow stromal cells (BMSCs). Co-cultures were imaged by fluorescent microscopy every other day to quantify cumulative population doublings (CPD) and cell morphology over the following 10 days. The effect of HDM on CPDs was also evaluated in the human RPMI-8226 MM cell line. 5TGM1-GFP cells were isolated by FACS on day 10 for evaluation of senescence histological characteristics and gene expression. All studies represent n=3 independent experiments unless otherwise indicated. HDM-5TGM1 cells exhibited a significant reduction in mean CPDs over 10 days compared to Veh (HDM 0.32±0.31, Veh 6.72±0.69, p<0.0001), indicating stable growth arrest in HDM treated cells consistent with senescence. HDM-5TGM1 cells were also significantly larger versus Veh (median size in pixels units: HDM 413.2±99.98, Veh 207±8.88, p<0.05), consistent with classical enlarged morphology in senescent cells. Preliminary assessment (n=1) of HDM-RPMI-8226 cells showed similar growth arrest (mean cumulative doublings: HDM 0.058±0.101, Veh 4.185±0.358) and enlargement (mean size in pixel units: HDM 804.1±6.048, Veh 526.9±2.115), suggesting a translatable mechanism in humans. FACS-sorted 5TGM1-GFP cells were stained for telomere associated foci (TAF), a marker of persistent DNA damage characteristic of senescent cells. HDM-5TGM1 cells showed a higher percentage of TAF+ cells (Percent TAF+ cells: HDM 39.7%±9.1%, Veh 10.6%±0.8%, n=2). Sorted HDM-5TGM1 cells also exhibited significant increases over Veh (p<0.001) in senescence markers ( Cdkn1a, Cdkn1c, Glb1), senescence cell anti-apoptosis pathway genes (SCAPs, Bcl2l1), and senescence associated secretory phenotype (SASP) genes ( Ccl5, Icam1, Mmp13). In addition, HDM-5TGM1 cells showed significant increases in myeloid markers that have previously been shown to be increased in dormant 5TGM1 ( Axl, Fcer1g, Mpeg1). Single cell RNA-sequencing was used to further evaluate senescence gene expression changes in growth arrested HDM-5TGM1 cells. Gene set enrichment analysis (GSEA) of genes differentially expressed in HDM-5TGM1 versus Veh cells was performed for custom senescence phenotyping gene sets (Senescence Up, SenUp; Senescence Growth Arrest, SenGA; Inflammatory SASP, iSASP; SCAPs; and Plasma Cell Senescence; PCSen) as well as mouse ortholog versions of a published senescence and biological aging gene set (SenMayo) and KEGG curated gene sets. GSEA of HDM-5TGM1 versus Veh cells confirmed significant (FDR<0.25) upregulation of iSASP, MayoSen, PCSen, SenUp, SCAPs, and SenGA gene sets. Concurrently, GSEA revealed significant downregulation of KEGG DNA replication, cell cycle, and nucleotide excision repair gene sets, supporting our observations of proliferative arrest and persistent DNA damage TAF. Our findings demonstrate that HDM-MM cells exhibit multiple features of senescence, suggesting a potential mechanistic role for TIS in MM dormancy and highlight a novel therapeutic target that may be present in patients post-HDM. Thus, targeting senescence may be a novel approach to eliminate dormant MM cells and prevent relapse.

Efficacy and Safety of Brl-101, CRISPR-Cas9-Mediated Gene Editing of the BCL11A Enhancer in Transfusion-Dependent β-Thalassemia

BACKGROUND: β-Thalassemia is an inherited hemolytic disease that is prevalent worldwide. Over 200 mutations in the HBB gene, which encodes adult hemoglobin (HbA), result in β-thalassemia. Hereditary persistence of fetal hemoglobin (HbF) can alleviate the symptoms of anemia. CRISPR-Cas9-mediated disruption of the BCL11A erythroid enhancer results in the reduction of BCL11A expression and the induction of fetal γ-globin, which is a practicable therapeutic strategy for treating transfusion-dependent β-thalassemia (TDT). METHODS: We obtained mobilized autologous CD34+ cells from 4 TDT patients sponsor initiated in phase I/II clinical trial (NCT05577312) and 6 TDT patients in investigator initiated clinical study（NCT04211480, NCT04205435）respectively. These cells were edited with CRISPR-Cas9 RNP at the +58 erythroid specific enhancer region of the BCL11A gene and then reinfused after the patients had undergone myeloablative busulfan conditioning. We subsequently monitored adverse events, neutrophil and platelet engraftment. Efficacy assessments included proportion of transfusion-independent (TI) subjects, levels of total hemoglobin and HbF, and proportion of red blood cells expressing HbF in peripheral blood. TI was evaluated for elimination of transfusions starting 42 days after the last transfusion and Hb above 90 g/L. RESULTS: Between October 15, 2019 and November 20, 2022, 10 patients with TDT were enrolled and received BRL-101 with a median age of 12.4 years (6-26). Among all the treated patients, 5 patients were β 0/β 0 phenotype, 4 patients were β0/β+ phenotype and 1 patient were β +/β + phenotype. As of July 20, 2023, the median follow- up was 24.6 months (4.3-39.2 m) (Tab.1). All of 10 patients achieved TI. The median duration of TI was 22.1 months (1.3 - 37.2 m). The longest duration of TI was 37.2 months (Fig.1). The levels of HbF ranged from 2.3 to 140.7g/L and the levels of total hemoglobin ranged from 105.7 to 149 g/L (Fig.2). At 6 months after BRL-101 infusion, the proportion of HbF-expressing red blood cells in peripheral blood had reached 96.5%, and then continued to rise and remained around 98-99% (Fig.3). Treatment-related adverse events were typical of those associated with myeloablation and autologous stem-cell transplantation, mainly manifested as hematological toxicities (Tab.2, Tab.3). 3 patients experienced adverse events (AEs) grade ≥ 3 which related to BRL-101. 4 patients experienced serious AEs (SAEs), including decreased platelet count, shock, febrile infection, soft tissue infection, and veno-occlusive liver disease. Only decreased platelet count may related to BRL-101, the others were due to busulfan treatment. All the SAEs were resolved. No study drug-related withdrawals or deaths occurred during treatment. CONCLUSIONS: Whether genotype was β 0/β 0 or non-β 0/β 0, BRL-101 demonstrated clinically meaningful increases in total Hb and HbF which occurred early and have been maintained over time, the safety profile of BRL-101 is generally consistent with that of myeloablative conditioning and autologous hematopoietic stem cell transplant. The updated data with 10 patients reported here are consistent with previous reports and support continued investigation of BRL-101 as a potential functional cure for patients with TDT.

Easix Indices Predict CRS and Overall Survival in Adult CAR-T Cell Recipients

Background: Immunotherapy with Chimeric Antigen Receptor T cells (CAR-Τ) is worldwide commercially available for refractory B cell malignancies, with continuously expanding indications.Given that cytokine release syndrome (CRS) and neurotoxicity (ICANS) are encountered in many CAR-T recipients both in trials and real-world setting, novel predictive and prognostic markers are highly needed. Aim: To this end, we hypothesized that EASIX (Endothelial Activation and Stress Index) and the most recently described modified EASIX (mEASIX) would be associated with severe CRS, ICANS and/or Overall Survival (OS) in the real-world setting. Methods: We collected data from consecutive adult patients (pts) from six transplant centers in Greece. Tisagenlecleucel and axicabtagene ciloleucel were administered since 2020, and brexucabtagene autoleucel since 2022. All pts received lymphodepleting therapy before CAR-T cell infusion with combination of cyclophosphamide and fludarabine. For patient monitoring as well as for prophylaxis and treatment of side effects, the EBMT and MD Anderson guidelines were adopted. EASIX (lactate dehydrogenase [LDH; U/L] x creatinine [mg/dL]/platelet [PLT] count; 10 9/L]) and mEASIX (which replaces creatinine with CRP [mg/dL]) were calculated before lymphodepletion (baseline), at day of infusion (0), and day 14 (14). The following variables were analyzed: age, gender, disease type and phase, product type, time from collection to product arrival and to infusion, progression-free (PFS) and overall survival (OS), laboratory markers at pre-specified time-points (LDH, creatinine, platelets, ferritin, CRP). Data cut-off date was end of June 2023, with at least 1 month of follow-up post infusion. Multivariate models were not performed due to multicollinearity issues. Results: Ninety pts, aged 49 (18-75) years, received commercial CAR-T cell products (33 tisagenlecleucel, 37 axicabtagene ciloleucel, 11 brexucabtagene autoleucel) for refractory/relapsed DLBCL (56), PMBCL (5), TFL (8), B-ALL (10), or MCL (11) after a median of 3 (1-9) previous lines of treatment including autologous (n=13) or allogeneic (n=7) transplantation. Severe (grade 3-4) CRS and ICANS were noted in 21% and 39%, respectively. Severe CRS was associated with mEASIXbaseline (p=0.025), and CRPbaseline (p=0.001), EASIX14 and m-EASIX14 (p<0.001). Both mEASIXbaseline and m-EASIX14 were able to predict severe CRS in ROC curve (AUC=0.768, p=0.032 and AUC=0.712, p=0.027). Severe ICANS did not correlate with EASIX indices, except for a trend towards statistically significant association with EASIX14 (p=0.054). On the other hand, severe ICANS was associated with increased LDH at baseline (p=0.001). With a median follow-up of 6.6 (1-42) months, 1-year PFS and OS were 33.2% and 62.5% respectively. Baseline values of ferritin and LDH, CRP values at all time-points, EASIX14 and mEASIX14 were associated with OS. Both EASIX indices predicted death in ROC curves. Similarly, EASIX14 was associated with PFS. Conclusions: This multicenter study, based on real-world experience with CAR-T cell therapy, confirms the predictive value of EASIX and mEASIX not only for life-threatening complications but also for survival outcomes. The implementation of EASIX may therefore aid in the selection of patients who are candidates for interventions to mitigate untoward sequelae of CAR-T therapy.

Correlation between Progression-Free Survival and Overall Survival in Patients with Relapsed Hodgkin Lymphoma: An Analysis of Individual Patient Data from Randomized GHSG Trials

Background: Progression-free survival (PFS) and overall survival (OS) are predominant measures of treatment efficacy in Hodgkin lymphoma (HL). Despite preference for OS from many regulatory authorities, PFS is most relevant to patients and frequently serves as primary endpoint in clinical trials. Recently we found a strong correlation between treatment effects on PFS and OS in the first-line setting (Bröckelmann PJ et al. EHA23/ICML23). However, their relationship in the relapsed setting remains unclear. We aimed to evaluate the correlation of PFS with OS after treatment of relapsed HL. Methods: We evaluated individual patient data of 375 patients with relapsed HL treated within the prospective randomized GHSG trials HDR1 (N= 141) and HDR2 (N= 234) between 02/1993 - 06/2007. Briefly, both trials included patients of 18 to 60 years of age with histologically confirmed relapsed HL after ≥1 prior line of treatment, who had not previously received high-dose chemotherapy and autologous stem-cell transplantation (ASCT). In HDR1 patients received two cycles of Dexa-BEAM (dexamethasone, carmustine, etoposide, cytarabine, and melphalan) and either two further courses of Dexa-BEAM or high-dose BEAM and ASCT. In HDR2, patients were assigned to two cycles of dexamethasone, cytarabine, and cisplatin (DHAP), and thereafter randomly assigned to either BEAM followed by ASCT or sequential cyclophosphamide, methotrexate, and etoposide in high-doses before BEAM followed by ASCT. All patients who received at least one dose of salvage chemotherapy within the respective trial were included in the analysis. We correlated treatment effects and risk factor effects on PFS and OS with the Wei-Lin-Weissfeld (WLW) method and adjusted the analysis for age and sex. Additionally, we applied copula models to correlate the time-to-event variables PFS and OS themselves using their marginal distributions. Results: With a median follow-up of 4.5 years, at least one PFS event, defined as relapse or progression of relapsed HL or death for any reason, was recorded in 146 of 375 patients (38.9%). At least one OS event, defined as death for any reason, was documented in 111 of 375 patients (29.6%). The hazard ratios for treatment effects on PFS and OS were 0.61 (95% confidence interval, CI= 0.38-0.98) and 1.01 (95% CI= 0.63-1.63) for HDR1 and 1.1 (95% CI= 0.69-1.75) and 0.8 (95% CI= 0.44-1.47) for HDR2, respectively. The WLW analysis revealed high correlations of treatment effects on PFS and OS at patient level within the trials. Pearson correlation r of the treatment effects on PFS and OS were r= 0.72 (95% confidence interval CI= 0.66-0.76, P< 0.001) in all 375 patients analyzed, r= 0.72 (95% CI= 0.63-0.79, P<0.001) in the HDR1 trial and r= 0.74 (95% CI= 0.67-0.79, P< 0.001) in the HDR2 trial. The analysis with different risk factors and copula models revealed similarly high correlations, confirming a strong relation between PFS and OS in relapsed HL patients. Conclusions: PFS and OS as well as treatment effects and prognostic effects on PFS and OS are highly correlated in patients treated for relapsed HL. Confirming results in first-line treatment, PFS thereby constitutes a highly relevant endpoint also in the setting of relapsed HL.

Should the Carbon Footprint of Care be Taken into Account When Choosing a Treatment for Lymphoma? a Case Application on Mantle Cell Lymphoma

OBJECTIVE While climate change represents the greatest threat of the current century on human health, the carbon footprint of the healthcare sector represents 7-10% of occidental countries green house gas (GHG) emissions. Purchases, mostly of drugs and medical devices, represent about 50% of emissions. Oncology and hematology are suspected to be particularly carbon intensive, as they require long term and frequent consumption of healthcare resources. Here, we estimate the carbon footprint associated with different therapeutic strategies (including chemo-free or high dose chemotherapy) in patients with Mantle Cell Lymphoma (MCL) and discuss their future health impacts. METHODS Standard immunochemotherapy based versus chemo-free strategies were compared both in 1) the ≤65 years old/fit and 2) in the >65 years old/unfit populations. Namely, we compared 1) immunochemotherapy induction (rituximab, dexamethasone, cytarabine, and a platinum derivative) followed by autologous stem-cell transplantation and 3-year rituximab maintenance (LyMa) to obinituzumab, ibrutinib, venetoclax combination (OIV), and 2) rituximab, bendamustine combination (RB) to rituximab, ibrutinib combination (RI). These treatment schemes were considered to have similar clinical efficacy in each sub-group of patients. Carbon footprints were estimated by considering drugs, medical devices, hospital stays, car journeys, medical biology and imaging consumption in the French context. Drug specific method (including production, packaging and transport with or without R&D, sales, general and administrative costs), and non-drug specific methods using mean emission factors based on their costs (kgCO2eq/€ from the French Environment Agency (ADEME) and the US Environmentally-Extended Input-Output (USEEIO) models) were applied to estimate drug carbon footprints and were compared in a sensitivity analysis. Carbon footprints were translated into future disability adjusted life years (DALY, a metric similar to quality adjusted life years QALY) expected to be lost in the future using the ReCiPe 2016 model. RESULTS The carbon footprint of each therapeutic strategy varied from 6.6 to 69.1 tCO2eq. In each, >70% of the total carbon footprint was related to drug purchase. A larger fraction (10-70%) of the carbon footprint of biotherapies (rituximab, obinituzumab) and low-cost small molecules (cotrimoxazole, valaciclovir) is related to their production while it is smaller (<10%) for high-cost small molecules (ibrutinib, venetoclax) that require higher R&D, sales, general and administrative costs. In the ≤65 years old/fit population, treating a patient with LyMa leads to the emission of 16.8 tCO2eq corresponding to an estimated 0.21 [95%CI 0.08-0.51] induced DALY. Treating a patient with OIV for 5 years leads to the emission of 69.1 t CO2eq (0.86 [0.35-2.09] DALY) whereas stopping the treatment at 2 years leads to the emission of 36.6 tCO2eq (0.46 [0.19-1.11] DALY). In the >65 years old/unfit population, treating a patient with RB leads to the emission of 6.6 tCO2eq (0.08 [0.03-0.2] DALY) while treating a patient with RI for 5 years leads to the emission of 41.1 tCO2eq (0.51 [0.21-1.25] DALY) whereas stopping the treatment at 2 years leads to the emission of 22.7 tCO2eq (0.28 [0.12-0.69] DALY). These estimates have to be taken with caution, as they are highly dependent on the method chosen. Using non-drug specific ADEME or USEEIO mean emission factors increase the carbon footprint of 2 year OIV from 36.6 tCO2eq to 164 tCO2eq and 313 tCO2eq, respectively. On the contrary, only accounting for drug production, packaging and transport diminishes its carbon footprint to 10.8 tCO2eq. Detailed discussion on the models, on the impact of R&D and on the use of generic/biosimilar drugs will be provided at the congress. CONCLUSIONS Treatment of patients with MCL is associated with a significant carbon footprint. Integrating their carbon footprint in the therapeutic decisions (such as length of treatment) could lead to significant decreases in carbon emissions that could translate into less health damages to future generations. Drug specific carbon accounting methods seem more adapted than nonspecific ones to estimate the carbon footprint of high cost drugs . Future research is required to determine more precisely the carbon footprint of drugs and therapeutic strategies in patients with hematological malignancies.

CAR19 Therapy Drives Expansion of Clonal Hematopoiesis and Associated Cytopenias

Background: For patients with relapsed/refractory large B-cell lymphomas (rrLBCL), CD19-directed chimeric antigen receptor T cells (CAR19) improve survival compared to autologous hematopoietic cell transplantation (HCT). However, major toxicities of CAR19 therapy include prolonged cytopenias and associated infections. To better understand the impact of CAR19 on such toxicities, we studied a cohort of LBCL patients achieving durable remissions to assess immune recovery after CAR19 treatment. We (1) compared immune reconstitution in HCT vs CAR19 treated patients, (2) performed molecular analysis of post-CAR19 cytopenic marrow specimens, and (3) profiled emergent mutations in cell free DNA (cfDNA) before and after CAR19. Methods & Results: We first propensity matched rrLBCL patients treated at Stanford with either CAR19 (100% axi-cel) or HCT who achieved durable remissions. Patients were matched based on age, sex, prior systemic lines of therapy, and time from infusion. From 471 eligible cases, propensity score matching was successful in 138 (n=69 per arm). When compared to HCT-treated counterparts, CAR19-treated patients had reduced recovery of absolute lymphocyte counts (ALC) and absolute neutrophil counts (ANC; longitudinal regression day 28-800 ANOVA p<0.005), but similar recovery of hemoglobin and platelets. CAR19-treated patients experienced significantly more Grade ≥3 infections in competing risk analyses (HR 2.61, CI 1.26-5.42), and higher non-relapse mortality (log-rank p=0.027). Next, to characterize mechanisms underlying cytopenias after CAR19, we profiled marrow aspirates from cases requiring biopsy due to prolonged cytopenia or clinical concern for myeloid neoplasms. No patient had evidence of lymphoma relapse at the time of biopsy, and all were >60d from CAR19 infusion (median 377d, range 86-1561d). Among 21 patients profiled by DNA sequencing, 18 (86%) had evidence of ≥1 somatic mutation in genes canonically associated with clonal hematopoiesis (CH) in the marrow ( Fig. 1A), with the most recurrently mutated genes being DNMT3A (38%), TP53 (33%), PPM1D (24%), ASXL1 (14%), and TET2 (14%). Among 6 patients diagnosed with and requiring therapy for a myeloid malignancy, all (100%) had a canonical myeloid karyotypic aberration detected by FISH, as compared with 0 in the 14 other evaluable cases ( Fig. 1A). CAR19 cells were proportionately enriched in the marrow relative to paired peripheral blood by flow cytometry (n = 12, median 2.5-fold enrichment, Wilcoxon p<0.001). Using 10x scRNA-Seq, viable CAR19 was detectable in 7 of 8 marrows (88%) and were predominantly CD4+. We hypothesized that CH clones detectable after CAR19 would also be present in pre-CAR19 blood samples and detectable in cfDNA. To test this, we profiled 786 longitudinal samples from 141 patients using CAPP-seq and serially monitored CH clones in cfDNA. Among 141 eligible cases, 40 (28%) were evaluable for CH, in having both pre- and post-CAR19 infusion specimens, while in durable remission (median follow up 967d). Of 51 CH clones detected in post-infusion cfDNA, 46 (90.1%) were also detectable prior to CAR19, typically expanding post-infusion (median = 1.8-fold, Fig. 1B). We next tested whether expanding CH clones showed evidence for selection after CAR19. Strikingly, among 48 recurrently mutated genes tested, DNMT3A and PPM1D showed significant evidence for clonal selection and expansion after CAR19 (Q-value < 0.05). When compared to patients without emerging CH clones, patients with ≥5-fold clonal expansions of canonical CH genes (23% of cases) had reduced ANC, but not ALC, recovery (median ANC=1.43 vs 2.43 at 6-mo, Wilcoxon p<0.001). This association remained significant in multivariate longitudinal regression that included age, sex, prior lines of therapy, and pre-infusion ANC (ANOVA p = 0.007). Conclusion: CAR19 treated patients experience reduced immune reconstitution and higher infection rates than HCT treated counterparts. Bone marrow findings reveal prolonged CAR19 cytopenia to commonly be associated with clonal cytopenia of undetermined significance (CCUS). Despite durable lymphoma remissions, canonical myeloid clonal expansions are common post-CAR19, and associated with myelosuppression. Non-invasive genotyping could aid in early identification of patients at risk for prolonged cytopenias after CAR19 and inform interventions to decrease associated complications.

Durable Efficacy and Manageable Safety in Patients Age ≥ 75 Years with Relapsed/Refractory Large B-Cell Lymphoma Treated with Tisagenlecleucel in the Real-World Setting

Background: Tisagenlecleucel is an autologous CD19-directed chimeric antigen receptor (CAR)-T cell therapy approved for the treatment of patients (pts) with relapsed/refractory (r/r) large B-cell lymphoma (LBCL) who have received ≥2 lines of prior therapy. Previous analysis of the Center for International Blood & Marrow Transplant Research (CIBMTR) registry showed high rates of durable response with progression-free survival (PFS), duration of response, and overall survival (OS) rates at 24 mo of 28%, 53%, and 44%, respectively, as well as similar efficacy outcomes among pts age ≥65 y as compared with pts age <65 y (Landsburg et al, ASH 2022). Although it has been shown that real-world pts treated with CAR-T cell therapy are older than those included in pivotal trials, limited data on CAR-T outcomes among pts age ≥75 y are available. Here, we report the first analysis of clinical outcomes in pts age ≥75 y with r/r LBCL treated with tisagenlecleucel in the real-world setting. Methods: Data were collected as a part of a noninterventional, prospective, longitudinal study using the CIBMTR cellular therapy registry. All pts were treated in the United States, Canada, or Israel. Efficacy outcomes analyzed included overall response rate (ORR), complete response rate (CRR), PFS, and OS. Key safety outcomes included the incidence and severity of adverse events, cytokine release syndrome (CRS), and immune effector cell-associated neurotoxicity syndrome (ICANS). Nominal P values are reported without adjusting for multiplicity. Results: As of May 4, 2023, 1375 pts had received tisagenlecleucel (infused set); 278 pts were age ≥75 y. Pts age ≥75 y had similar baseline characteristics compared with pts age <75 y (Eastern Cooperative Oncology Group 0-1, 85% in both populations; elevated lactate dehydrogenase [LDH], 47% in both populations), received similar lymphodepleting regimens, and received tisagenlecleucel in a similar number of days post relapse (81 d vs 85 d, respectively). Pts age ≥75 y had a lower frequency of prior autologous hematopoietic cell transplantation than pts age <75 y (12% vs 26%, respectively) (Figure). One hundred twenty-one pts age ≥75 y had comorbidities (121/278, 44%), including pulmonary disease (65/278, 23%), cardiac disease (60/278, 22%), and hepatic disease (21/278, 8%). Among 247 pts age ≥75 y who were evaluated for efficacy, the ORR (CR + partial response) was 64% (95% CI, 58.1-70.3) and CRR was 47% (95% CI, 41.0-53.8). ORR was similar in pts age <75 y (n=984; 60% [95% CI, 56.9-63.1]), as was CRR (46% [95% CI, 43.2-49.5]). With a median length of follow-up (infusion to data cutoff) of 30 mo, 24-mo PFS in pts age ≥75 y was 23% (95% CI, 16.7-30.1) compared with 28% in pts age <75 y (95% CI, 25.1-31.7). Twenty-four-mo OS in pts age ≥75 y was 39% (95% CI, 31.2-47.2) compared with 44% (95% CI, 40.1-47.8) in pts age <75 y (Figure). AE frequency in pts age ≥75 y (n=250) was comparable with pts age <75 y (n=1004), including the incidence of all-grade CRS (57% vs 60%, respectively; P=0.31) and grade 3/4 CRS (6% of each subgroup). Grade 5 CRS occurred in 2 pts age ≥75 y and 6 pts age <75 y. Tocilizumab was used to manage CRS in 66% of pts age ≥75 y compared with 56% of pts age <75. All-grade ICANS frequency in pts age ≥75 y was comparable with pts age <75 y (27% vs 22%, respectively; P=0.06). Grade 3/4 ICANS was experienced by 7% of each subgroup. Four pts age ≥75 y experienced grade 5 ICANS compared with 1 pt age <75 y. Median time to ICANS onset was similar in pts age ≥75 y (5 d, range 2.0-6.5) and pts age <75 y (5 d, range 3.0-8.0). Corticosteroids were used with similar frequency to manage ICANS in pts age ≥75 y (68%) compared with pts age <75 y (65%). Conclusions: In the first analysis of pts age ≥75 y, tisagenlecleucel demonstrated similar efficacy and rates of CRS and ICANS in pts with r/r LBCL age ≥75 y as compared with age <75 y. As few pts with r/r LBCL age ≥75 y received CAR-T cell therapy in clinical trials, real-world evidence for this age group is invaluable for guiding treatment decisions in this clinical setting, and supports consideration of tisagenlecleucel, a therapy that results in durable disease control in approximately one quarter of patients with a low risk of severe toxicity.

Real-World Experience with RTOG 0227 Induction for First Line Therapy of Primary CNS Lymphoma (PCNSL)

Introduction PCNSL is an aggressive and rare subtype of extranodal non-Hodgkin Lymphoma affecting the brain, spinal cord, cerebrospinal fluid (CSF), leptomeninges and/or vitreoretinal components. While there have been trials comparing outcomes of consolidation treatment with whole brain radiation therapy (WBRT) versus (vs) autologous hematopoietic cell transplantation (auto-HCT) following different induction regimens in PCNSL, the optimal induction regimen to pair with these forms of consolidation remains controversial. Our group adopted a modified version of the RTOG 0227 induction as our standard PCNSL induction in 2017. This regimen includes 5 cycles of Methotrexate (MTX) at 3.5 g/m 2 and Rituximab (R) at 375-500 mg/m 2, and Temozolomide (TMZ) on cycles 2 and 4. Based on the published phase 2 trial of 53 patients (pts), the regimen is significantly less toxic than more aggressive induction regimens such as MATRiX, especially in older pts or those with comorbidities. We evaluated our real-world outcomes in PCNSL pts treated with RTOG 0227 induction followed by consolidation with either WBRT/TMZ or auto-HCT, at a single academic university hospital. Methods We identified newly diagnosed PCNSL pts treated at a single academic university hospital between 2017 and 2023. Electronic medical records were retrospectively reviewed to collect data including demographics, clinicopathological features, treatment details, response rates, long-term follow up, disease recurrence, and survival. The IELSG prognostic index tool was used for risk assessment. All pts received induction regimen consisting of R (dose between 375- 500 mg/m 2) and 3.5 g/m 2 of MTX with leucovorin on weeks 1, 3, 5, 7 and 9 along with TMZ daily for 5 days on weeks 4 and 8, followed by consolidation with either WBRT/TMZ or auto-HCT. In WBRT cohort, maintenance TMZ was given at 200mg/m 2 daily for 5 days every 28 days, for total of 10 cycles, and dose was reduced if side effects developed. Objective response rate (ORR) and complete response rate (CRR) after induction chemotherapy were calculated. Overall survival (OS) and progression free survival (PFS) at 2 years were estimated with the Kaplan-Meir method (using GraphPad Prism 9.3.1) and compared between the WBRT and auto-HCT cohorts, using the log-rank test. Results A total of 29 PCNSL pts were included in the study. Patient and disease characteristics for the entire cohort, as well as pts treated with WBRT vs auto-HCT consolidation, are shown on the Table. On average (avg), pts received 4 cycles of MTX and 8 cycles of TMZ. Nine (31%) pts developed acute kidney injury and 1 (3.4%) developed transaminitis from MTX. The avg total cumulative TMZ dose was 5913 mg/m 2 and 8 (27.5%) pts required TMZ dose reduction. Treatment related mortality (TRM) following induction was 0%. Eight (27.5%) pts had complete response, 19 (65.5%) had partial response, 1 (3.5%) had stable disease and 1 (3.5%) had disease progression. ORR was 93.1% and CRR was 27.5%. Eighteen (62%) pts received WBRT/TMZ consolidation, while 11 (38%) received auto-HCT consolidation. Median dose of WBRT administered was 36 Gy (23.4 to 36 Gy). Thirteen (72.2%) pts received 36 Gy in 30 fractions (fx) of 1.2 Gy BID, 4 (22.2%) pts received 23.4 Gy in 13 fx of 1.8 Gy OD, and 1 (5.5%) pt received 30.6 Gy in 17 fx of 1.8 Gy OD. Most common conditioning regimen prior to auto-HCT was carmustine/thiotepa (BCNU/TT). With a median follow up of 36 months, 4 (22.2%) pts in WBRT cohort and 1 (9.1%) in auto-HCT cohort had disease recurrence. Two-year PFS was 83% overall, 81% for the WBRT pts and 87% for the auto-HCT pts, with a p value of 0.65 for log-rank comparison of PFS for the WBRT vs auto-HCT pts. Two-year OS was 96% for the entire cohort, 94% for the WBRT pts and 100% for the auto-HCT pts, with a p value of 0.27 for log-rank comparison of OS for the WBRT vs auto-HCT pts. Conclusion In this real-world cohort of PCNSL pts not treated as part of a clinical trial, we observed excellent outcomes using the modified RTOG 0227 induction regimen. PFS and OS at 2 yrs in our cohort exceeds those reported with any prospective clinical trial to date, and with zero TRM to date. This data indicates that the modified RTOG 0227 induction with either WBRT or auto-HCT consolidation represents a very tolerable and highly effective option for first line therapy of PCNSL, for both younger and older pts.