Citations

ABSTRACT First‐line therapy for mantle cell lymphoma (MCL) represents a critical opportunity for clinical benefit via sustained complete response. We conducted a phase 2 multicenter trial in the academic and community cancer research united (ACCRU) network, testing a multitargeted 1st line regimen. CARiBOU (ACCRU‐LY‐1804) employs alternating VR‐CAP and R‐cytarabine with continuous acalabrutinib, in six 21‐day cycles, for previously untreated MCL. The primary endpoint was complete metabolic response (CMR) rate. Secondary endpoints included safety, feasibility of stem cell collection, proportion proceeding to ASCT, and progression‐free (PFS) and overall survival (OS). Peripheral blood measurable residual disease (MRD) was tested using the ClonoSEQ assay (Adaptive Biotechnologies). Of 41 patients enrolled, 39 (95%) responded to therapy, including 37 patients achieving CMR (90%). Two nonresponders discontinued therapy for toxicity early, prior to study‐defined restaging, and received alternate therapy. Undetectable MRD at a 10 6 threshold was achieved in 26/33 tested patients (79%), and 94% at 10 5 . 18‐month estimated PFS is 79% (95% CI 64%–97%), and OS is 96% (95% CI 88%–100%). Toxicities were primarily hematologic (grade 3 hematologic AE in 32 patients, [78%]). Twelve required platelet transfusions, and one grade 3 bleeding event occurred. Febrile neutropenia occurred in 4 patients, and 6 (14%) experienced SAEs. There were no treatment‐related deaths. CARiBOU is an efficient, highly effective outpatient 1st line MCL regimen, employing intermediate‐dose cytarabine and continuous acalabrutinib for 6 cycles. This multitargeted regimen addresses the biologic heterogeneity of MCL and permits flexible MRD‐guided decisions on consolidation and maintenance. Trial Registration: ClinicalTrials.gov identifier: NCT04626791

8057 Background: The NCI Adjuvant Lung Cancer Enrichment Marker Identification and Sequencing Trials (ALCHEMIST) study tested resected stage II-IIIB(N2) NSCLC for targetable EGFR and ALK alterations and PD-L1 expression to screen patients for biomarker-driven adjuvant therapy trials (NCT02194738). Local lab results were requested when available for comparison to central lab results. Methods: We identified patients with both central and local PD-L1 results in the ALCHEMIST adjuvant immunotherapy study screening population. Discrepancies in tumor proportion score (TPS) between central and local PD-L1 were defined using prespecified cut-points (granular: <1%, 1-<5%, 5-<10%, 10-<20%, 20-<30%, 30-<40%, 40-<50%, 50-60%, 60-<70%, 70-<80%, 80-<90%, 90-<100%; clinical: <1%, 1-<50%, 50-100%). Large discrepancies were defined as ≥ 50 percentage point differences; for these cases, local PD-L1 and hematoxylin & eosin-stained slides were requested. These and all central slides were digitally scanned at 40X. Three expert pathologists reviewed the scanned slides in a blinded fashion. Differences between patient or tumor characteristics were assessed by Chi-square and Wilcoxon rank sum tests. Percent agreement was computed within and between the reviewers. Results: Central and local PD-L1 results were available for 497 patients. 177 cases (36%) had discrepancies that placed patients in different clinical TPS categories (<1%, 1-<50%, 50-100%). Among these, 43 cases had large TPS discrepancies; 14 had available local testing slides. 46 of the 320 cases without discrepancy were randomly selected as controls. No patient or tumor characteristics were associated with discrepancy, including tumor location, histology, grade or cancer stage (p > 0.05). Pairwise comparisons of TPS according to three pathologists re-reading the same scanned PD-L1 slides showed similar levels of disagreement in clinical TPS category whether there was initial discrepancy between central and local results (24%, 34%, and 23%; mean 27%) or not (33%, 30%, and 20%; mean 28%). Among the 14 cases with large initial discrepancies and local slides available, there was agreement in clinical TPS category when the anonymized central and local scanned slides were re-read by the pathologists in 54%, 38%, and 43% of cases, despite 100% non-agreement in initial reads. There were higher rates of agreement when the tested slides both originated from the same (100%) versus different (35%) blocks, when the same (48%) versus different (40%) PD-L1 antibodies were used, and when the cases were of non-squamous (52%) versus squamous (14%) cell carcinoma. Conclusions: There are substantial differences in PD-L1 TPS read by pathologists that can result in placement of patients in different categories commonly used for clinical management. These differences have clear implications in clinical trials and routine patient care.

8001 Background: The ALCHEMIST clinical trial platform, launched by the National Clinical Trials Network (NCTN) in 2014, screened patients with resected non-small cell lung cancer (NSCLC) for molecular markers and tailored post-operative adjuvant therapy trials. A081105 evaluated whether adjuvant erlotinib improved overall survival (OS) following complete resection in patients with early stage EGFR mutated lung adenocarcinoma. Methods: A081105 was a randomized phase III trial enrolling patients with completely resected stage IB (≥4 cm), II, or IIIA non-squamous NSCLC (per the 7 th TNM staging classification) harboring EGFR exon 19 deletion or L858R mutations. Patients were randomized 1:1 to erlotinib 150 mg daily for up to 2 years or placebo/observation, stratified by stage, prior chemotherapy, EGFR mutation subtype, and ECOG performance status. The primary endpoint was OS in the per-protocol (PP) population with centrally confirmed EGFR mutations, designed to detect a hazard ratio (HR) of 0.67 in favor of erlotinib with a power of 86% and one sided type I error rate of 5%. Secondary endpoints included OS and disease free survival (DFS) in a modified intent-to-treat (mITT) population with local or centrally confirmed EGFR mutations, and safety. A prespecified backstop analysis was conducted after a minimum of 5 years of follow-up on all patients. Results: Trial enrollment was discontinued when 390 of the intended 450 patients had been enrolled due to the proven benefit of adjuvant osimertinib. Among 390 enrolled patients, the arms were balanced for age (median: 67.0 years), sex (70% female), race (70% white), stage (II: 51%, IIIA: 37%), prior chemotherapy (82%), ECOG PS 0 (60%), and exon 19 deletion (57%). Adjuvant erlotinib did not significantly improve OS compared with placebo/observation in the overall PP population (364 patients, 108 events, HR 0.89; 95% CI, 0.59–1.34; 1-sided P = 0.29) or within exon 19 deletion (HR: 0.94) or L858R mutation (HR: 0.82) subgroups. Five-year OS rates were 78.6% versus 77.9%, respectively. Results were consistent in the mITT analysis (379 patients, 113 events, HR 0.86; 95% CI, 0.58–1.28). Erlotinib improved DFS (mITT: 181 events, median: 68 vs 50 months, HR 0.74; 95% CI, 0.55–1.01). Across both arms, 11% of patients started non-protocol treatment (Osimertinib: 9%) prior to disease progression, and 9% withdrew consent for all follow-up prior to recurrence. In the erlotinib arm, 3 deaths on study were reported; grade 3 or higher adverse events were reported on 39% of patients. Median duration of treatment on Erlotinib arm was 16 months; only 37% of patients completed the planned treatment. Conclusions: In resected EGFR -mutant NSCLC, adjuvant erlotinib did not improve overall survival but improved DFS. Additional studies are exploring efficacy in selected subsets of patients using genomics and proteomic analyses. Clinical trial information: NCT02193282 .

Abstract Background: Patients with residual invasive disease after neoadjuvant chemotherapy (NAC) for HER2-positive breast cancer remain at high risk for recurrence even with standard adjuvant trastuzumab emtansine (T-DM1). H2NVAC, a multi-epitope HER2 peptide vaccine, has previously demonstrated the ability to elicit robust and durable immune responses. Here, we assessed the safety and early immunogenicity of H2NVAC in combination with T-DM1 in this high-risk population. Methods: Patients with stage II-III HER2-positive breast cancer and residual invasive disease following NAC and HER2-directed therapy received standard adjuvant T-DM1 alongside six priming doses of H2NVAC administered every 3 weeks. The primary endpoint was the occurrence of dose-limiting toxicity (DLT) within 21 days of the first vaccination, with adverse events graded per CTCAE v5.0. Immunogenicity assessments included HER2-specific T-cell responses measured by IFNγ ELISpot and HER-specific serum antibodies measured by ELISA at baseline and 30 days after the sixth priming dose. Results: 20 patients were enrolled. H2NVAC plus T-DM1 was well tolerated with no DLTs observed. All treatment-emergent AEs were grade 1-2, with fatigue (grade 1 60%, grade 2 5%), peripheral sensory neuropathy (grade 1 35%, grade 2 10%), elevated alkaline phosphatase (grade 1 40%), nausea (grade 1 35%, grade 2 5%), arthralgia (grade 1 30%), and injection-site reactions (grade 1 50%) being most common. Robust vaccine-specific T-cell responses by ELISpot were observed in 94% of evaluable patients, who mounted HER2-specific T-cell responses at 30 days after the sixth priming dose, with a mean 197-fold increase over baseline. Further CYTOF analysis showed a significant decrease in exhausted T-cell phenotypes, with reduced LAG3 and TIM3 expression on both CD4+ and CD8+ T cells. For antibody responses by ELISA, 26% of patients developed HER2 protein-specific antibody responses at this time point. There was no significant increase in antibodies to H2NVAC peptides or to unrelated tumor antigens (p53, IGFBP2, TERT, myoglobin) at 30 days after the sixth vaccine. Ongoing correlative analyses will assess the evolution of immune responses at later time points following completion of T-DM1 therapy. Conclusions: Concurrent administration of H2NVAC with T-DM1 was safe and did not increase toxicity beyond single-agent T-DM1. To our knowledge, this is the first study to demonstrate that a cancer vaccine can be delivered concurrently with an antibody-drug conjugate without increasing adverse effects while still eliciting robust T-cell responses. Ongoing analyses will further define the kinetics and durability of vaccine-induced antibody and T-cell responses at later time points, as well as evaluate the efficacy of H2NVAC in reducing recurrence risk in the randomized phase 2 trial. Citation Format: Saranya Chumsri, Sharmila Giri, Andy J. Ness, David W. Hillman, Nadine Norton, Davitte Cogen, Brian M. Necela, Aziza Nassar, Donald W. Northfelt, Pooja Advani, Rohit Rao, Alvaro Mareno-Aspitia, Brenda Ernst, Kathryn J. Ruddy, Matthew P. Goetz, Keith L. Knutson. Safety, tolerability, and early immune responses in the safety run-in of an HER2 multi-epitope vaccine combined with T-DM1 in residual HER2-positive breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 6715.

Abstract Introduction: First-line therapy for mantle cell lymphoma (MCL) represents a critical opportunity for clinical benefit via sustained complete response. Multitargeted combinations, including optimized chemotherapy with novel agents targeted to MCL, may best address the biologic heterogeneity of this disease. Building on prior experience using modified VR-CAP and R-cytarabine, we enhanced this regimen by adding acalabrutinib while reducing cytarabine, aiming for improved efficacy and safety without impeding stem cell collection. To evaluate this regimen, we conducted a phase 2 multicenter trial at four centers in the Academic and Community Cancer Research United (ACCRU) network. Methods: CARiBOU (ACCRU-LY-1804) employs alternating VR-CAP and R-cytarabine with continuous acalabrutinib, in six 21-day cycles, for previously untreated MCL. Eligible patients (pts) were at least 18 years old with adequate organ function, measurable disease, no CNS involvement; and were ASCT-eligible per investigator. VR-CAP (cycles 1, 3, and 5) employed bortezomib 1.3 mg/m² subcutaneously days 1,8, and 15; rituximab 375 mg/m² day 1; cyclophosphamide 750 mg/m² day 1; doxorubicin 50 mg/m2 day 1; and prednisone 100 mg PO days 1-5. Cycles 2,4, and 6 used outpatient rituximab with cytarabine at 3 g/m² x 2 daily doses in the first 5 pts, after which the dose was reduced to 2 gm/m2 x 2 daily doses due to thrombocytopenia. Acalabrutinib 100 mg p.o. twice daily was given continuously but held for grade 4 thrombocytopenia or clinically significant toxicity. Growth factors and prophylactic antimicrobials were required. Responses were assessed after six cycles using FDG PET/CT, bone marrow aspirate/biopsy (BM Bx), and endoscopy when indicated (Lugano 2014). The primary endpoint was complete metabolic response (CMR) rate at end of treatment (EOT). Secondary endpoints included safety, feasibility of stem cell collection, proportion proceeding to ASCT, and progression-free (PFS) and overall survival (OS). Peripheral blood measurable residual disease (MRD) was evaluated using the ClonoSEQ assay (Adaptive Biotechnologies). A Simon two-stage design was used, targeting a CMR rate ≥ 70% versus a null rate of 50%, with a total sample size of 39 evaluable pts. Results: 41 pts were accrued from October 2021 through May 2025, 37 of whom completed all 6 cycles and are evaluable for response; two are still on therapy, and two discontinued therapy early for toxicity. Median age was 63 years (range 41-73), 22% were female, and 85% were White. MIPI risk groups were low (44%), intermediate (39%), and high (17%), and Ki-67 was ≥ 30% in 54% of pts. Three pts (7%) had known TP53 mutations by sequencing. At EOT, the CMR rate was 85.3% among all pts (35/41; 95% CI 67.9%-92.9%), or 94.5% among evaluable pts (35/37). BM Bx was performed in 31 pts at EOT, 30 of which (96.8%) were negative for MCL. Undetectable peripheral blood MRD using a 10^6 threshold (uMRD6) was achieved at EOT in 78.1% (25/32) of tested pts, and 93.8% (30/32) achieved uMRD5. Nine of 41 pts underwent ASCT; no patient failed stem cell collection. Maintenance therapy was not protocol-defined but included rituximab in 91.9% of pts and a BTK inhibitor in 21.6% of pts. With a median follow-up of 16.7 months, PFS and OS rates at 18 months were 76.7% (95% CI: 60.7%-96.9%) and 95.5% (95% CI: 87.1%-100%). Toxicities were primarily hematologic. Grade 3+ toxicities included thrombocytopenia (66.6%), neutropenia (28.2%), and anemia (25.6%). Grade 3+ febrile neutropenia was observed in 10.2% of pts. Peripheral neuropathy was seen in 20.5% of pts and all grade 1-2. Bleeding events included purpura in 2 pts (5.2%) and epistaxis in 1 patient (2.6%). One case of atrial fibrillation was observed. Eighteen pts required temporary dose hold of acalabrutinib for toxicity (mainly thrombocytopenia), and 2 had acalabrutinib dose reductions. Serious adverse events occurred in 6 pts, and no treatment-related deaths occurred. Conclusions: CARiBOU is an efficient, highly effective outpatient regimen for 1st line MCL, employing intermediate dose cytarabine with continuous acalabrutinib. With supportive care and platelet monitoring, this approach safely yielded high rates of CMR and uMRD6, supporting multitargeted induction therapy for appropriate pts with untreated MCL.

Abstract Background: Despite the promising efficacy of CAR-T for patients with relapsed or refractory (R/R) large B-cell lymphomas (LBCL), more than 60% of patients will relapse, the majority of which occur in the first 6 months. Approximately 30% of patients with LBCL treated with CAR-T achieve a partial response (PR) on day 30 (D30) PET-CT assessment. Of patients in a D30 PR, 70% will eventually progress, yet the standard of care remains close observation. Early consolidative treatment strategies utilizing therapies with a different mechanism of action may improve outcomes, but there are currently no reliable biomarkers. Epcoritamab (Epco), a bispecific antibody directed against CD20 and CD3, has been approved by the FDA for LBCL patients who relapse after at least 2 lines of therapy. By treating prior to overt relapse, Epco has the potential to salvage inadequate responses post CAR-T. This study is a trial-in-progress that will evaluate the efficacy of epco compared to observation for patients with LBCLs achieving a PR on D30 post CAR-T PET-CT assessment. Methods This is an investigator-initiated, randomized, phase II, multicenter, open-label study (NCT06238648) evaluating epco monotherapy for a fixed duration of 12 cycles compared to observation for LBCL patients with D30 PR after standard of care CAR-T. A maximum of 120 patients will be randomized 1:1 to epco or observation across 10 academic centers. Stratification factors include line of CAR-T (second vs third line) and costimulatory domain (CD28 vs 4-1BB). Key inclusion criteria include PET evidence of a D30 PR. non-bulky disease ( &lt;7.5cm), ANC of &gt;1000, hemoglobin &gt;7 g/dL if asymptomatic or &gt;8 if symptomatic, platelet count &gt;50,000. G-CSF, pRBCs and platelet transfusions are allowed. Key exclusion criteria include ongoing or uncontrolled CRS or ICANS, and active or symptomatic CNS disease. This study is available to all eligible patients, regardless of race, gender, or ethnic origin. To adapt to current practices, prior bispecific antibody exposure is allowed if used as holding or bridging therapy without disease progression. Epco is administered subcutaneously at a dose of 0.16mg on day 1, 0.8mg on day 8, prior to full dose of 48mg on day 15. Epco is administered weekly in 28 day cycles (C) for C1-3, on day 1 and 15 of C4-9 and on day 1 of C10-12. PET-CT response is assessed by the 2014 Lugano criteria after 2 cycles, and then every 3 months during active treatment. The primary objective is efficacy, measured as conversion from D30 PR to CR. The secondary endpoints include frequency and severity of treatment emergent adverse events, ORR, duration of response, duration of complete response, progression free survival, event free survival, and overall survival. Peripheral blood samples will be collected pre-treatment and during treatment to assess for biomarkers of response and resistance and CAR-T persistence. The study was activated in January 2024 and recruitment is ongoing.

Introduction PET-directed therapy using ABVD with or without radiation therapy (RT) is considered standard in early stage classic Hodgkin lymphoma (cHL). Brentuximab vedotin (BV) and nivolumab (NVB) have transformed the treatment paradigm in advanced stage disease, but their roles remain uncertain in the management of early stage cHL. CALGB 50604 evaluated 2 cycles of ABVD followed by 2 more cycles of ABVD in patients with negative interim PET or 2 cycles of escalated BEACOPP and RT (3060 cGy) in patients with positive interim PET. More recently, ACCRU-LY1601 evaluated 3 cycles of BV+AVD followed by NVB consolidation in interim PET-negative patients. Interim PET-positive patients received 4 cycles of BV+NVB prior to NVB consolidation. Both studies had similar eligibility criteria as phase 2 trials in early stage non-bulky cHL. We hypothesize that patients who receive novel agents as part of frontline therapy (ACCRU-LY1601) may have superior clinical outcomes compared to those who receive conventional chemotherapy with or without RT (CALGB 50604) in adjusted analysis. Methods The primary endpoint was the progression free survival (PFS) rate at 3 years for both studies. The following secondary endpoints were analyzed: PET negativity (defined as Deauville score 1-3) at interim assessment, response rates, and adverse events (AEs). Data from the ACCRU-LY1601 up to May 2024 were included. Patient characteristics, complete metabolic response (CMR) rates, and AE incidence were compared with Fisher's exact tests. Kaplan-Meier techniques were used to estimate landmark survival rates; the 95% confidence intervals (CI) for probabilities of PFS at 3 years landmark rates were assessed. Results of a formal propensity-matched analysis are forthcoming. Results Two-hundred twenty-nine participants receiving frontline therapy for early stage, non-bulky cHL were identified for analysis (N=149 from CALGB 50604; N=80 from ACCRU-LY1601). Median age in both cohorts was 31 (ranges: 18-58 in CALGB 50604 and 19-60 in ACCRU-LY1601). The majority of patients were white (84.6% in CALGB 506048 and 82.5% in ACCRU-LY1601; P=0.58) and had stage II cHL (85.2% in CALGB 50604 and 88.8% in ACCRU-LY1601; P=0.83) with ECOG score of 0 (75.2% in CALGB 50604 and 75.0% in ACCRU-LY1601; P=0.87). B symptoms were present in 27.4% and 32.9% of patients in CALGB 50604 and ACCRU-LY1601, respectively (P=0.44). At time of analysis, the median follow-up was 3.8 years for CALGB 50604 and 3.6 years for ACCRU-LY1601. Interim PET results were available for 140/149 CALGB 50604 and 77/80 ACCRU-LY1601 cohorts; 90.1% and 94.8% were interim PET negative in CALGB 50604 and ACCRU-LY1601, respectively (P=0.31). Thirteen patients (8.7%) received RT after positive interim PET per the study protocol in CALGB 50604. No patient received RT while enrolled in ACCRU-LY1601 although 2 patients (2.5%) received RT off protocol. Seventeen PFS events (11.4%) were observed in CALGB 50604 while one event (1.3%) was observed in ACCRU-LY1601. Reported estimates of 3-year landmark PFS were 89.0% (95% CI, 84-95%) in CALGB 50604 and 97.5% (95% CI, 83.6-99.6%) in ACCRU-LY1601. Grade ≥ 3 AEs, including febrile neutropenia (6.3% in CALGB 50604 vs. 8.8% in ACCRU-LY1601; P=0.59), were similar between the trial cohorts. All grade peripheral sensory neuropathy was reported in 41.6% and 37.5% (Grade ≥ 3: 2.8% and 2.5%; P&gt;0.99) of patients in CALGB 50604 and ACCRU-LY1601, respectively. Conclusion CALGB 50604 and ACCRU-LY1601 represent two recent studies aimed at developing new strategies to reduce exposure to cytotoxic chemotherapy and RT in early stage cHL. Both studies share the same primary endpoint with similar eligibility criteria, making the comparative analysis feasible. There was no significant difference in major baseline patient characteristics between the two studies. They also showed similar toxicity profiles, including comparable rates of febrile neutropenia and peripheral sensory neuropathy. ACCRU-LY1601 was associated with a higher rate of estimated 3-year PFS rate compared to CALGB 50604 (97.5% vs. 89.0%) although their CIs overlapped. Overall, the current data demonstrate the potential role of incorporating novel agents in frontline therapy to further reduce the use of cytotoxic chemotherapy and RT while improving survival outcomes, providing a strong basis for designing future trials in early stage cHL.

7012 Background: DLBCL with expression of MYC and BCL2 (double expressor lymphoma, DEL), has an adverse prognosis. Venetoclax, an inhibitor of BCL2, was previously studied in combination with R-CHOP. A051701 is a phase II/III randomized trial of chemoimmunotherapy +/- venetoclax in DEL and double hit lymphoma cohorts. Here we report initial phase II results from the DEL cohort. Methods: Patients (pts) age ≥ 18 years (y) with untreated DEL were randomized 1:1 to R-CHOP (Arm 1) or R-CHOP-venetoclax (Arm 2). DEL was defined as MYC expression ≥40% and BCL2 expression ≥50%, without double hit cytogenetics. Enrollment was based on local pathology results that were centrally confirmed. Venetoclax 800 mg was given orally days 4-8 of cycle 1 and days 1-5 of subsequent cycles for up to 6 cycles. All cycles were supported by GCSF or peg-GCSF. The primary endpoint was progression-free survival (PFS) with 84% power to detect a HR of 0.518 corresponding to 2y PFS rate of 65% in Arm 1 and 80% in Arm 2 (1-sided α=0.20). Results: 119 DEL pts were enrolled: 60 Arm 1; 59 Arm 2. Analyses were performed for the modified intent-to-treat population, defined as eligible pts with confirmed DEL histology (n=113; 56 Arm 1, 57 Arm 2). Median age was 64 y (range 22-85); baseline demographic factors were well balanced except for advanced stage (more common in Arm 1; (77% vs 60%, p=0.051). Most pts were non-germinal center B cell-like by immunohistochemistry (Arm 1 72%, Arm 2 58%), high-intermediate/high risk IPI (Arm 1 54%, Arm 2 51%) and ECOG performance status 0-1 (Arm 1 95%, Arm 2 86%). BCL2 rearrangements were detected in 25% and 33% of pts on Arm 1 and Arm 2, respectively. Most pts completed therapy per protocol (84% Arm 1, 75% Arm 2). Median follow up is 27 months (m). No difference in PFS was observed with 12-m PFS estimates of 77% in Arm 1, 76% in Arm 2 [HR = 0.98 (95% CI: 0.48 – 2.01), p=0.95]. The end of treatment (EOT) overall and complete response rates among patients with an EOT assessment were 87.5% and 70% in Arm 1, and 90% and 82% in Arm 2. Overall survival (OS) was not statistically significantly different with 12-mo OS estimates of 94% in Arm 1 and 79% in Arm 2 [HR = 1.27 (95% CI: 0.57 – 2.79), p=0.56]. Grade ≥3 adverse events (AEs) occurred more frequently in Arm 2 (42% vs 76%). The most commonly increased grade ≥3 AEs included neutropenia (20% vs 47%), anemia (4% vs 25.5%), thrombocytopenia (5.5% vs 24%), febrile neutropenia (7% vs 16%) and fatigue (0% vs 11%). No grade 5 AEs on treatment were reported on Arm 1, and 3 were reported on Arm 2 (lung infection and sudden death NOS, both possibly related; respiratory failure, unlikely related). Conclusions: Adding venetoclax to R-CHOP in DEL pts did not improve PFS and resulted in increased toxicity. The study did not meet its primary endpoint in phase II, and so did not proceed to phase III. Clinical trial information: NCT03984448 .