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INTRODUCTION T-cell prolymphocytic leukemia (T-PLL) is a rare, aggressive malignancy of mature T-cells. Although responses may been seen with initial alemtuzumab-based therapy, relapse is inevitable and relapsed/refractory disease carries a dismal prognosis. T-PLL has shown in vitro sensitivity to venetoclax, and short-lived clinical responses to venetoclax monotherapy (Smith, Blood Advances 2020; Boidol, Blood 2017) or when given in combination with pentostatin (Alfayez, Leukemia & Lymphoma 2020). Given the lack of standard treatment options, we reviewed the outcomes of patients (pts) with relapsed T-PLL on venetoclax-based therapy. METHODS Using an institutional clinical database of pts with T-PLL seen in the Division of Hematology at Mayo Clinic, Rochester, MN, all pts treated with venetoclax or venetoclax-based therapies in a relapsed/refractory setting were identified. Clinical, laboratory, and pathology data, as well as treatment dosing and toxicity were ascertained retrospectively from the medical records. Diagnostic criteria and response definitions were utilized as per the T-PLL International Study Group (Staber, Blood 2019). RESULTS Between 8/2017 and 5/2020, 9 pts with relapsed/refractory T-PLL treated with venetoclax were identified. The median age was 63 years (range 49-75), and one-third were male. Baseline characteristics are detailed in Table 1. Rearrangement of TCL1 family genes was present in all 8 pts evaluated with fluorescence in situ hybridization (FISH). Using conventional cytogenetics, a complex karyotype was present in 4/6 pts tested. The median prior lines of therapy was 3 (range 1-4), including alemtuzumab in 8 of 9 pts (intravenous 7/8); and two pts had undergone prior hematopoietic stem cell transplantation (1 allogeneic; 1 autologous) after achieving a complete remission. Additional individual pt details are included in Table 2. Prior to venetoclax therapy initiation, 2 pts had B-symptoms (2 night sweats; 1 fever) and 6 pts had an ECOG score ≥ 2. Lymphadenopathy and splenomegaly were present in 6 and 9 pts, respectively. Extranodal involvement included 3 pts with cutaneous involvement and 5 pts with effusions (4 ascites; 1 pleural). The target maximum dose of venetoclax (800 mg [n=4]; 400 mg [n=1]) was reached by 5 pts at a median of 12 days (range 7-40 days). The other 4 pts had disease progression after a median of 10 days (range 5-22 days) during the dose ramp-up, including 2 pts undergoing rapid dose escalation. Altogether, 6 of the 9 pts initiated venetoclax with a rapid dose escalation. Bendamustine was given with venetoclax in 5/9 pts; median number of cycles 1 (range 1-4) with variable starting dosing (range 60-100 mg/m2). The disease control rate was 56%; best response was partial remission (PR) in 4 (44%) pts and stable disease (SD) in 1 (11%) pt. The 1 pt with SD received venetoclax monotherapy; however, the overall response rate among pts who received the combination of venetoclax and bendamustine was 80% (4/5 pts). One pt with a partial remission met all criteria for complete remission but did not have a confirmatory bone marrow biopsy. Cutaneous disease improved in 2 of 3 pts (both with PR as best response), and effusions improved in 2 of 5 pts (1 PR and 1 SD as best response). Among those in PR, the median decrease in absolute lymphocyte count was 67x109/L and the median decrease in lactate dehydrogenase was 1,162 U/L (normal range 122-222 U/L). Median duration of treatment for all pts was 42 days (range 4-201 days). All pts ultimately died during follow-up with a median overall survival of 53 days (range 4-464 days); Figure 1. All pts experienced at least one adverse event and 8 of 9 pts had a grade ≥ 3 toxicity, most commonly edema (n=7) and neutropenia (n=6). Five pts required dose interruptions due to neutropenia (n=3), tumor lysis syndrome (n=1), and edema (n=1). Three pts had dose reductions, all from 800 mg dosing, due to hematologic toxicity (n=2) and nausea (n=1). No pts discontinued venetoclax as a result of adverse events. CONCLUSION Treatment of pts with relapsed/refractory T-PLL remains a significant unmet need. The 9 pts described herein represent the largest cohort of pts treated with venetoclax-based therapy in this setting to the current date. Despite initial reports of clinical efficacy, our results show that venetoclax (with or without bendamustine) has modest efficacy in the treatment of relapsed/refractory T-PLL after prior alemtuzumab exposure. Disclosures Parikh: TG Therapeutics: Research Funding; Verastem Oncology: Honoraria; GlaxoSmithKline: Honoraria; AbbVie: Honoraria, Research Funding; Genentech: Honoraria; Merck: Research Funding; MorphoSys: Research Funding; Pharmacyclics: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Ascentage Pharma: Research Funding; AstraZeneca: Honoraria, Research Funding. Shah:Dren Bio: Consultancy. Bennani:Verastem: Other: Advisory Board; Affimed: Research Funding; Purdue Pharma: Other: Advisory Board; Kite/Gilead: Research Funding. Wang:Incyte: Research Funding; Novartis: Research Funding; Innocare: Research Funding. Kenderian:MorphoSys: Research Funding; Lentigen: Research Funding; Gilead: Research Funding; Juno: Research Funding; BMS: Research Funding; Tolero: Research Funding; Sunesis: Research Funding; Kite: Research Funding; Novartis: Patents & Royalties, Research Funding; Torque: Consultancy; Humanigen: Consultancy, Patents & Royalties, Research Funding; Mettaforge: Patents & Royalties. Kay:MEI Pharma: Research Funding; Oncotracker: Membership on an entity's Board of Directors or advisory committees; Abbvie: Research Funding; Morpho-sys: Membership on an entity's Board of Directors or advisory committees; Acerta Pharma: Research Funding; Cytomx: Membership on an entity's Board of Directors or advisory committees; Juno Theraputics: Membership on an entity's Board of Directors or advisory committees; Dava Oncology: Membership on an entity's Board of Directors or advisory committees; Bristol Meyer Squib: Membership on an entity's Board of Directors or advisory committees, Research Funding; Tolero Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Research Funding; Rigel: Membership on an entity's Board of Directors or advisory committees; Agios Pharma: Membership on an entity's Board of Directors or advisory committees; Pharmacyclics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Sunesis: Research Funding; Astra Zeneca: Membership on an entity's Board of Directors or advisory committees. Ding:Octapharma: Membership on an entity's Board of Directors or advisory committees; Astra Zeneca: Research Funding; alexion: Membership on an entity's Board of Directors or advisory committees; Beigene: Membership on an entity's Board of Directors or advisory committees; MEI Pharma: Membership on an entity's Board of Directors or advisory committees; Merck: Membership on an entity's Board of Directors or advisory committees, Research Funding; DTRM: Research Funding; Abbvie: Research Funding. OffLabel Disclosure: Venetoclax: off-label use in treatment of relapsed/refractory T-cell prolymphocytic leukemia

Introduction: Anaplastic large cell lymphomas (ALCLs) are CD30-positive T-cell lymphomas classified into ALK-positive and ALK-negative. The ALK-negative ALCLs are a genetically heterogeneous group that includes DUSP22-rearranged, TP63-rearranged and triple-negative cases. The DUSP22-rearranged ALCLs characteristically grow in a diffuse sheet-like pattern and are composed of intermediate-sized monomorphous hallmark cells, admixed with smaller cells with prominent nuclear indentations and occasional central nuclear pseudo inclusions (King RL et al, Am J Surg Pathol. 2016). Further, DUSP22-rearranged ALCL is a molecularly distinct subset of ALCL with a unique immunogenic phenotype that portends a favorable prognosis (Luchtel RA et al. Blood 2018). Lymphoid enhancer binding factor (LEF1) is a crucial nuclear mediator of the Wnt/ β-catenin pathway and a transcription factor involved in T-cell maturation. However, limited data exists on the association of LEF1 in T-cell lymphomas, including ALCL. The aims of this study were to explore LEF1 expression by immunohistochemistry in different subsets of ALCLs and to analyze the association of Wnt/ β-catenin pathway in this cohort. Methods: After approval by the institutional review board, we screened pathology reports from January 1, 1995 to December 31, 2019 and identified patients with a diagnosis of ALCL using our institutional database. Details on fluorescence in situ hybridization studies in ALK-negative cases were documented. Immunostaining for LEF1 and β catenin was performed on all cases where formalin fixed paraffin embedded tissue was available. The presence or absence of β catenin nuclear staining was recorded. LEF1 nuclear staining in the neoplastic ALCL cells was graded as negative (0), weak (1+), intermediate (2+) or strong (3+) and the percentage of LEF1-positive neoplastic cells was detailed (Figure 1). LEF1 scoring was performed by manual counting of the stained nuclei out of all tumor nuclei by two pathologists (A.R. and M.S.) and the grading was reviewed by another pathologist (P.J.K.). Results: We evaluated 45 ALCL cases, including 41 (91.1%) ALK-negative and 4 (8.9%) ALK-positive ALCLs. Among the ALK-negative ALCLs, there were16 DUSP22-rearranged, and 25 non-DUSP22-rearanged (7 TP63-rearranged and 18 triple-negative) cases. Fifteen (94%) of 16 DUSP22-rearranged ALCLs showed strong expression of LEF1 in >75% tumor cells (Figure 2). In contrast, this strong and uniform LEF1 overexpression was only detected in 1 of 29 (3%) of the remaining ALCL cases (P <.0001) (Table 1). We previously characterized a distinctive molecular signature in ALK-negative ALCLs with DUSP22-rearrangements using gene expression microarray analysis on frozen ALCL tissue samples (Luchtel RA et al. Blood 2018). On examining LEF1 gene expression in this previously published dataset, DUSP22 -rearranged cases had significantly higher LEF1 expression than any other genetic subtype (triple-negative, TP63-rearranged, or ALK-positive). Overall, mean LEF1 expression was 6.3-fold higher in ALCLs with DUSP22 rearrangements than in ALCLs without DUSP22-rearrangements (P=0.0001). LEF1 is a coactivator of the Wnt/β-catenin pathway; therefore, it is reasonable to hypothesize the overexpression of LEF1 may promote Wnt/β-catenin signaling. However, all LEF1-positive cases were negative for β-catenin by immunohistochemistry, suggesting that LEF1 overexpression is independent of the Wnt/β-catenin pathway signaling in these cases. Conclusions: There is a striking association between high LEF1 expression and DUSP22-rearrangements in ALCLs. The strong and uniform LEF1 expression pattern has a high positive predictive value (94%) and high negative predictive value (96%) for DUSP22- rearrangement in ALK-negative ALCLs (Table 2). The combination of characteristic morphologic and molecular features of DUSP22-rearranged cases with the unique LEF1 expression further emphasizes that DUSP22-rearranged ALCL represents a distinct clinicopathologic subset of ALCL. Disclosures No relevant conflicts of interest to declare.

Background: Multiple myeloma (MM) negatively affects health-related quality of life (HRQoL), and with each relapse, patients with MM experience further declines in HRQoL. Patient-reported HRQoL is therefore an important treatment outcome, in addition to clinical response to therapy. CARTITUDE-1 (NCT03548207) is a phase 1b/2 study evaluating the safety and efficacy of ciltacabtagene autoleucel (cilta-cel; JNJ-68284528; LCAR-B38M CAR-T cells), a chimeric antigen receptor T (CAR-T) cell therapy with 2 B-cell maturation antigen-targeting single-domain antibodies, in patients with relapsed/refractory (R/R) MM. We evaluated symptoms, functioning, and overall HRQoL through patient-reported outcome measures, which is a secondary objective of CARTITUDE-1. Methods: Patients were ≥18 years of age with a diagnosis of MM per International Myeloma Working Group criteria, measurable disease, and Eastern Cooperative Oncology Group performance status ≤1. Patients had received ≥3 prior regimens for MM or were double-refractory to a proteasome inhibitor and immunomodulatory drug, and had received an anti-CD38 antibody. Cilta-cel was given as a single infusion on Day 1 (target dose: 0.75×106 [range: 0.5-1.0×106] CAR+ viable T cells/kg) 5-7 days after start of lymphodepletion (cyclophosphamide 300 mg/m2 + fludarabine 30 mg/m2 daily for 3 days). In the phase 2 portion of CARTITUDE-1, HRQoL was assessed at baseline, on Days 7, 28, 56, 78, and 100, and every 28 days thereafter using 3 patient-reported instruments: the European Organization for Research and Treatment of Cancer QoL Questionnaire Core 30 (EORTC QLQ-C30), 4 items from the EORTC QLQ-Multiple Myeloma (MY20) module, and the 5-level EuroQol Five Dimension (EQ-5D-5L) measure. Raw EORTC QLQ-C30 and EORTC QLQ-MY20 scores were linearly transformed to a scale ranging from 0 to 100; the EQ-5D-5L visual analog scale (VAS) score ranges from 0 to 100. Clinically meaningful changes in EORTC QLQ-C30 symptoms, physical functioning, and overall HRQoL were based on anchor-based methods using a patient global impression of change item. Repeated-measures mixed-effects models were used to analyze mean changes in HRQoL from baseline to subsequent assessment time points in patients in the modified intent-to-treat population with ≥1 post-baseline assessment. Median time to event of HRQoL scores was calculated descriptively, using a change in score ≥0.5×standard deviation of values prior to cilta-cel infusion as improvement/worsening with death due to progression defined as worsening. Results: For the 68 patients in the phase 2 portion of CARTITUDE-1 (63.2% male; median age: 62.0 years [range: 43-78]), questionnaire completion rates at baseline and Day 100, respectively, were 92.6% and 69.2% for both the EORTC QLQ-C30 and EORTC QLQ-MY20 items and 92.6% and 70.8% for the EQ-5D-5L. For EORTC QLQ-C30 subscales, clinically meaningful improvements at Day 100 were seen for 71.1% of patients for pain, 62.2% for fatigue, 72.1% for physical functioning, and 51.1% for global health status. Mean changes in pain and fatigue showed a reduction in these symptoms over time (following an initial worsening of fatigue at Day 7; Figure). This trend of improvements over time was also observed for overall HRQoL and EORTC QLQ-MY20 single items. Clinically meaningful improvements at Day 100, defined by a literature-based minimal important difference of 10 points in mean score, were observed for the EORTC QLQ-MY20 single items: thinking about illness and worries about dying or future health. Approximately 50% of the population reported an event of improvement or worsening in EORTC QLQ-C30 and EQ-5D-5L scales, with the rest censored in this early data cut; among these patients, median time to improvement was approximately 1-2 months (with median time to worsening occurring less than 1 month after cilta-cel treatment). There was a trend for an improvement in mean EORTC QLQ-C30 global health status, physical functioning, pain, and fatigue, and EQ-5D-5L VAS at Day 100 with increased depth of response. Conclusions: Some patients with heavily pretreated MM showed rapid and clinically meaningful improvements in pain, fatigue, physical functioning, overall HRQoL, and future perspectives, consistent with their clinical outcomes. With additional follow-up, it is possible that these early improvements in symptoms will translate into greater improvement in overall HRQoL in the long term. Disclosures Martin: Janssen: Research Funding; Sanofi: Research Funding; AMGEN: Research Funding; Seattle Genetics: Research Funding; GSK: Consultancy. Lin:Vineti: Consultancy; Janssen: Consultancy, Research Funding; Kite, a Gilead Company: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Novartis: Consultancy; Legend BioTech: Consultancy; Bluebird Bio: Consultancy, Research Funding; Juno: Consultancy; Merck: Research Funding; Takeda: Research Funding; Gamida Cells: Consultancy; Sorrento: Consultancy, Membership on an entity's Board of Directors or advisory committees. Cohen:Kite Pharma: Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees; Takeda,: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; GlaxoSmithKline: Membership on an entity's Board of Directors or advisory committees; Novartis: Other: Patents/Intellectual property licensed, Research Funding; Oncopeptides: Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: Membership on an entity's Board of Directors or advisory committees; AstraZeneca: Membership on an entity's Board of Directors or advisory committees; Genentech/Roche: Membership on an entity's Board of Directors or advisory committees. Htut:City of Hope Medical Center: Current Employment. Stewart:Janssen, BMS, Sanofi-Aventis, GSK: Honoraria; Tempus, Inc., Genomics England LLC: Membership on an entity's Board of Directors or advisory committees. Hari:GSK: Consultancy; BMS: Consultancy; Takeda: Consultancy; Amgen: Consultancy; Incyte Corporation: Consultancy; Janssen: Consultancy. Berdeja:Teva: Research Funding; Cellularity: Research Funding; Kesios: Research Funding; BMS: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; CURIS: Research Funding; EMD Sorono: Research Funding; Genentech, Inc.: Research Funding; Karyopharm: Consultancy; Poseida: Research Funding; Novartis: Research Funding; Lilly: Research Funding; Amgen: Consultancy, Research Funding; Acetylon: Research Funding; Glenmark: Research Funding; Janssen: Consultancy, Research Funding; Vivolux: Research Funding; Takeda: Consultancy, Research Funding; Servier: Consultancy; CRISPR Therapeutics: Consultancy, Research Funding; Constellation: Research Funding; Bluebird: Research Funding; Abbvie: Research Funding; Prothena: Consultancy; Bioclinica: Consultancy; Kite Pharma: Consultancy; Legend: Consultancy. Madduri:Foundation Medicine: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; GSK: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Speaking Engagement, Speakers Bureau; AbbVie: Consultancy, Honoraria; Legend: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Speaking Engagement, Speakers Bureau; Kinevant: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Speaking Engagement, Speakers Bureau; Celgene: Consultancy, Honoraria. Usmani:Takeda: Consultancy, Honoraria, Other: Speaking Fees, Research Funding; SkylineDX: Consultancy, Research Funding; Seattle Genetics: Consultancy, Research Funding; Merck: Consultancy, Research Funding; Incyte: Research Funding; Pharmacyclics: Research Funding; Janssen: Consultancy, Honoraria, Other: Speaking Fees, Research Funding; GSK: Consultancy, Research Funding; Abbvie: Consultancy; Array Biopharma: Research Funding; Celgene: Other; Amgen: Consultancy, Honoraria, Other: Speaking Fees, Research Funding; Sanofi: Consultancy, Honoraria, Research Funding; BMS, Celgene: Consultancy, Honoraria, Other: Speaking Fees, Research Funding. Yeh:Janssen: Current Employment. Allred:Janssen: Current Employment. Olyslager:Janssen: Current Employment. Banerjee:Janssen: Current Employment. Goldberg:Johnson & Johnson: Current Employment, Current equity holder in publicly-traded company. Schecter:Janssen: Current Employment. Jackson:Janssen: Current Employment; Memorial Sloan Kettering Cancer Center: Consultancy. Deraedt:Janssen: Current Employment, Current equity holder in publicly-traded company. Gries:Janssen: Current Employment, Current equity holder in publicly-traded company. Fastenau:Janssen: Current Employment, Current equity holder in publicly-traded company. Wu:Legend Biotech USA Inc.: Current Employment. Carrasco:Legend Biotech USA Inc.: Current Employment. Akram:Legend Biotech USA Inc.: Current Employment. Hossain:Legend Biotech USA Inc.: Current Employment. Jakubowiak:AbbVie, Amgen, BMS/Celgene, GSK, Janssen, Karyopharm: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Adaptive, Juno: Consultancy, Honoraria. Jagannath:BMS, Janssen, Karyopharm, Legend Biotech, Sanofi, Takeda: Consultancy.

Introduction: Novel targeted therapies have revolutionized treatments for both upfront and relapsed CLL. However, effective therapies have not been established for progressive CLL after developing resistance to both BTK inhibitor and BCL-2 inhibitors. Similarly, Richter's transformation (RS) remains an area of unmet clinical need. Hypothesizing that progressive CLL and RS possess significant but differential molecular abnormalities, we aimed to dissect the initial genomic profiles in a clinical cohort of patients seen in our routine clinical practice using targeted DNA sequencing and transcriptome analysis. Methods: Twelve CLL patients who had lymph node biopsies for evaluation of clinical progression at Mayo Clinic were included in this study. RNA sequencing and targeted DNA sequencing on a focused oncology panel of 1,711 genes were performed on Illumina HiSeq through Tempus Labs, Inc. (Chicago, IL). Differentially expressed (DE) genes were identified using edgeR at the cutoff of FDR <=0.05 and fold-change >=2. Somatic mutations and copy number alternations (CNAs) were identified through Mutect2 and PatternCNV, respectively. CN loss was defined to have log2(ratio) <=-0.93 and CN gain to have log2(ratio) >= 0.585. Pathway analysis was done through the Enrichr package. Results: Among the 12 patients, 7 had confirmed RS (large cell lymphoma histology) and 5 had CLL based on pathological findings. The clinical and therapeutic history for each patient is illustrated in Fig 1A. FISH results from 11 of the patients showed chromosomal abnormalities including del(13q), del(11q), del(17p) and tri(12) (Fig 1A). Hierarchical clustering of expression profiles from the top 10,000 most variable genes in expression revealed two major clusters (Fig 1A). Cluster C1 contains five RS cases, of which case S207 did not receive ibrutinib, S256 was on high-dose steroid and anti-CD20 post-ibrutinib therapy for >1 year before biopsy, and case S025 was treated for < 6 months with ibrutinib. These three form a subgroup separate from the other two RS in C1 who had 8 and 42 months of continuous ibrutinib therapy pre-biopsy, respectively. C2 contains two RS and five CLL cases. Within C2, CLL and RS cases showed similar transcriptomic profiles. Over 90% of the DE genes showed an overall increase of expression in C1, particularly within the 3-sample subgroup (Fig 1B). These genes are enriched in pathways known to play key roles in CLL, including PI3K-AKT signaling, NOTCH signaling and RAS/MAPK signaling, while genes up-regulated in C2 are enriched in WNT signaling. The results suggest marked differences in gene expression profiles and indicate molecular heterogeneity among RS and CLL patients. In addition, targeted DNA sequencing data were analyzed to identify somatic mutations and CNAs. The analysis confirmed the FISH results of del(13q), del(11q), del(17p) or tri(12) in 8 of the cases (Fig 1A). The mutation profiles are similar between C1 and C2 for the recurrently mutated genes published in CLL. However, we identified recurrent CNAs that occurred preferentially in C1 (covering 9 genes) or C2 (48 genes) (Fig 1C). Manual inspections of the reads coverage revealed that 5 of the 9 genes are from chr1q21.1 to chr1q22 that showed clear CN gains largely in C1. Of the 48 genes, 6 are from chrXp11 that showed CN losses, and 27 are from chr17q12 to chr17q25 that showed CN gains. Therefore, the majority of the 57 genes are from large-scale CNAs. Notably, for the CNAs mostly occurring in C2, the affected genes are enriched in WNT signaling, Cell cycle/protein kinase activity and chromatin modifying enzymes. Collectively, the results support the variability of transcriptomic signatures and genetic lesions between RS and CLL. Conclusion: This study revealed a noticeable heterogeneity in gene expression and genetic variation between RS and CLL, albeit in a small cohort. The vast majority of the DE genes showed elevated expression in C1 containing only RS cases, and these genes are enriched in PI3K-AKT signaling, NOTCH signaling, and RAS/MAPK signaling. The pattern is more pronounced for a subgroup in C1 who were overall less exposed to ibrutinib. For somatic variation, there is a strong tendency of occurrence of recurrent CNAs towards C2 cohort, mainly involving gains of chr17q and deletions of chrXp11. Given these advances we are encouraged to further pursue the genetic abnormalities with defined roles in aggressive and transformed CLL. Disclosures Liu: Eisal: Research Funding; Genentech: Research Funding; GRAIL: Research Funding; Menarini Silicon Biosystems: Research Funding; Merck: Research Funding; Seattle Genetics: Research Funding; Tesaro: Research Funding. Parikh:Genentech: Honoraria; Ascentage Pharma: Research Funding; AbbVie: Honoraria, Research Funding; Verastem Oncology: Honoraria; Pharmacyclics: Honoraria, Research Funding; GlaxoSmithKline: Honoraria; Merck: Research Funding; MorphoSys: Research Funding; TG Therapeutics: Research Funding; AstraZeneca: Honoraria, Research Funding; Janssen: Honoraria, Research Funding. Wang:Incyte: Research Funding; Innocare: Research Funding; Novartis: Research Funding. Kenderian:Gilead: Research Funding; Humanigen: Consultancy, Patents & Royalties, Research Funding; MorphoSys: Research Funding; Lentigen: Research Funding; Novartis: Patents & Royalties, Research Funding; Torque: Consultancy; Mettaforge: Patents & Royalties; BMS: Research Funding; Tolero: Research Funding; Sunesis: Research Funding; Juno: Research Funding; Kite: Research Funding. Kay:Tolero Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Research Funding; Juno Theraputics: Membership on an entity's Board of Directors or advisory committees; Cytomx: Membership on an entity's Board of Directors or advisory committees; Morpho-sys: Membership on an entity's Board of Directors or advisory committees; Agios Pharma: Membership on an entity's Board of Directors or advisory committees; Astra Zeneca: Membership on an entity's Board of Directors or advisory committees; Sunesis: Research Funding; MEI Pharma: Research Funding; Acerta Pharma: Research Funding; Rigel: Membership on an entity's Board of Directors or advisory committees; Oncotracker: Membership on an entity's Board of Directors or advisory committees; Abbvie: Research Funding; Bristol Meyer Squib: Membership on an entity's Board of Directors or advisory committees, Research Funding; Dava Oncology: Membership on an entity's Board of Directors or advisory committees; Pharmacyclics: Membership on an entity's Board of Directors or advisory committees, Research Funding. Braggio:DASA: Consultancy; Bayer: Other: Stock Owner; Acerta Pharma: Research Funding. Ding:Astra Zeneca: Research Funding; DTRM: Research Funding; Beigene: Membership on an entity's Board of Directors or advisory committees; alexion: Membership on an entity's Board of Directors or advisory committees; MEI Pharma: Membership on an entity's Board of Directors or advisory committees; Merck: Membership on an entity's Board of Directors or advisory committees, Research Funding; Octapharma: Membership on an entity's Board of Directors or advisory committees; Abbvie: Research Funding.

INTRODUCTION Nearly 20% of patients (pts) are ≥ 80 years (yrs) of age at the time of CLL diagnosis. Increased medical comorbidities, as well as declining functional status and organ function, often accompany advanced age. However, clinical trials often enroll a disproportionally low number of people from this age demographic due to stringent eligibility parameters, which provides limited evidence to guide decisions. Here, we report clinical characteristics and outcomes of pts ≥ 80 yrs of age at the time of CLL diagnosis. METHODS Between 1/1995 and 3/2020, we identified previously untreated CLL pts from the Mayo Clinic CLL Database who were ≥ 80 yrs of age at the time of CLL diagnosis, and seen within 3 yrs of diagnosis. Baseline characteristics, treatments administered, and time to first treatment (TFT) were analyzed for all pts. Overall survival (OS) was measured from diagnosis date in all pts and separately from treatment date for treated pts. Time to next treatment (TTNT) was measured in treated pts from first treatment date to date of second treatment or last known treatment. TFT and TTNT were analyzed accounting for competing risk of death. Standardized mortality ratio (SMR) compared observed survival to survival in a Minnesota population. Cox multivariable regression models were used to determine which factors were associated with OS (treatment as a time-dependent covariate) and TTNT (accounting for competing risk of death). RESULTS Among the 213 pts identified, the median age was 83 yrs (range 80-97); baseline characteristics are summarized in Table 1. The median number of medical comorbidities among all pts was 4 (range 0-8). At least 1 comorbidity was present in 97% of pts, most commonly hypertension (57%), genitourinary (n=48%), rheumatological (46%), and dyslipidemia (n=43%). Median follow-up was 3.8 yrs. A total of 56 pts received treatment and the median TFT was 6.7 yrs. Over this 25 year interval, the treatment approaches included monoclonal antibody alone (n=17), chemotherapy alone (n=17), or chemoimmunotherapy (n=14), novel agents (n=3), and multi-agent Richter's transformation regimens (n=5). Chlorambucil-based treatments (chlorambucil n=13, chlorambucil, prednisone n=3) were the most frequently used chemotherapy regimens. The most common chemoimmunotherapy regimens included rituximab, cyclophosphamide, prednisone (RCP) with (n=3) or without vincristine (n=6), and chlorambucil with an anti-CD20 monoclonal antibody (n=4; obinutuzumab n=2, rituximab n=2). Among 17 pts who received monoclonal antibody alone, treatments included rituximab alone (n=11), rituximab plus methylprednisolone (n=2), obinutuzumab (n=2), and rituximab with alemtuzumab (n=2). Frontline novel agent treatments included ibrutinib alone (n=1), acalabrutinib alone (n=1), and ibrutinib, obinutuzumab, venetoclax (n=1). Five pts with Richter's transformation (diagnosed concurrent with CLL n=4) received multi-agent chemotherapy. Among the 56 treated pts, 22 pts received second line therapy after a median TTNT of 2.8 yrs from start of first therapy. The most common second line treatments were chlorambucil-based (n=6) and rituximab-based (n=6) regimens. Age, sex, absolute lymphocyte count, del17p, and unmutated IGHV were not predictive of TTNT. The median OS among all 213 pts was 4.6 yrs. SMR was 1.2 (p=0.008) when excluding pts with Richter's transformation. In univariable analyses, receipt of therapy (HR 3.92, 95%CI 2.11-7.28; p<0.001), age (per 5 year increase; HR 1.84, 95%CI 1.43-2.38; p<0.001) and unmutated IGHV (HR 2.03, 95%CI 1.12-3.67; p=0.02) were predictors of shorter OS. The OS among pts who received treatment (Figure 1) was similar when compared across time periods of treatment start year grouped as 1995-2001 (n=10), 2002-2013 (n=32), and 2014-2020 (n=14). Treatment categories by time period are shown in Table 2. CONCLUSIONS In this study of 213 pts ≥ 80 yrs of age at time of CLL diagnosis, the median time to first therapy was ~7 yrs. Although survival outcomes did not differ by era across the 25-year span of this study, pts treated with novel agents were underrepresented and are a patient population which warrants additional evaluation. The finding that pts with CLL in this cohort had a 20% higher risk of death compared to an age- and sex-matched population emphasize the need for ongoing efforts to improve clinical outcomes for CLL pts in this demographic category. Disclosures Kenderian: Torque: Consultancy; Mettaforge: Patents & Royalties; Humanigen: Consultancy, Patents & Royalties, Research Funding; Novartis: Patents & Royalties, Research Funding; Kite: Research Funding; Gilead: Research Funding; Juno: Research Funding; BMS: Research Funding; Tolero: Research Funding; Sunesis: Research Funding; MorphoSys: Research Funding; Lentigen: Research Funding. Wang:Incyte: Research Funding; Innocare: Research Funding; Novartis: Research Funding. Shanafelt:Genentech, Pharmacyclics LLC, an AbbVie Company, AbbVie, GlaxoSmithKline, and Merck: Research Funding; Mayo Clinic: Patents & Royalties: and other intellectual property. Braggio:DASA: Consultancy; Bayer: Other: Stock Owner; Acerta Pharma: Research Funding. Kay:Morpho-sys: Membership on an entity's Board of Directors or advisory committees; Bristol Meyer Squib: Membership on an entity's Board of Directors or advisory committees, Research Funding; Tolero Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Research Funding; Oncotracker: Membership on an entity's Board of Directors or advisory committees; Juno Theraputics: Membership on an entity's Board of Directors or advisory committees; Rigel: Membership on an entity's Board of Directors or advisory committees; Cytomx: Membership on an entity's Board of Directors or advisory committees; Sunesis: Research Funding; MEI Pharma: Research Funding; Astra Zeneca: Membership on an entity's Board of Directors or advisory committees; Agios Pharma: Membership on an entity's Board of Directors or advisory committees; Abbvie: Research Funding; Pharmacyclics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Acerta Pharma: Research Funding; Dava Oncology: Membership on an entity's Board of Directors or advisory committees. Ding:alexion: Membership on an entity's Board of Directors or advisory committees; MEI Pharma: Membership on an entity's Board of Directors or advisory committees; Octapharma: Membership on an entity's Board of Directors or advisory committees; Abbvie: Research Funding; Astra Zeneca: Research Funding; Beigene: Membership on an entity's Board of Directors or advisory committees; DTRM: Research Funding; Merck: Membership on an entity's Board of Directors or advisory committees, Research Funding. Parikh:Merck: Research Funding; AstraZeneca: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; MorphoSys: Research Funding; Pharmacyclics: Honoraria, Research Funding; AbbVie: Honoraria, Research Funding; Ascentage Pharma: Research Funding; Genentech: Honoraria; Verastem Oncology: Honoraria; GlaxoSmithKline: Honoraria; TG Therapeutics: Research Funding.

Background: Cytogenetic abnormalities detected by fluorescence in situ hybridization (FISH) are known to differentially impact prognosis in patients with chronic lymphocytic leukemia (CLL). Deletion6q23 (del6q23) has been reported in ~2-3% of CLL patients at diagnosis; however, its prognostic significance remains indeterminate. Methods: We identified previously untreated CLL patients from the Mayo Clinic CLL Database seen between 1/1995 - 2/2020 who had FISH performed. The clinical characteristics, concomitant cytogenetic abnormalities, time to first therapy (TTFT), and overall survival (OS) were compared between patients with del6q23 to those without this abnormality. TTFT was analyzed from FISH date until treatment or last known untreated date, accounting for competing risk of death. OS was analyzed using Kaplan-Meier methods from FISH date. In a matched (CLL-IPI risk score and sex) analysis, Cox regression analysis was used to determine the association between TTFT/OS and presence of del6q23. The Mayo Clinic IRB approved this study. Results: A total of 3101 CLL patients were identified; their median age at diagnosis was 64 years and 66% were male. Of these patients, 42 (1.3%) had evidence of del6q23 by FISH. Compared to patients without del6q23, patients with del6q23 carried a more adverse clinical and cytogenetic profile at the time of diagnosis including advanced Rai stage (22% Rai III/IV vs. 9% Rai III/IV; P = 0.002), unmutated IGHV genes (91% vs. 43%; P < 0.001), and high/very high risk CLL-IPI (50% vs. 27%; P < 0.001). Del6q23 was the sole abnormality in 13 patients (31%). Of the remaining patients, del6q23 was concomitantly present with del13q in 8 patients (19%), and with either del11q or del17p in 21 patients (50%). Of the 42 patients with del6q23, 29 received first line therapy: chemoimmunotherapy in 16 patients, BTK inhibitor in 7 patients, and an anti-CD20 monoclonal antibody alone in 6 patients. The median follow-up of the entire cohort was 7.3 years. The median TTFT in patients with del6q23 was 0.7 years while the 5-year OS was 76%. Patients with del6q23 demonstrated significantly shorter TTFT and reduced OS when compared to patients without del6q23 (Figures 1A and 1B). The shorter TTFT was also evident for patients with del6q23 compared to patients without del6q23 divided according to the Dohner risk category (Figure 2A), although there was no difference in OS between these groups of patients (Figure 2B). Because del6q23 patients were enriched for other unfavorable prognostic markers, we identified four control patients without del6q23, matched by CLL-IPI risk score and sex, to each treatment-naïve patient with del6q23. Patients with del6q23 showed a borderline statistically significant shorter TTFT (median 0.7 years versus 3.9 years; P = 0.07) and a nonsignificant association with OS (median 10.9 years versus 10.3 years; P = 0.28). Conclusion: Del6q23 by FISH in previously untreated CLL represents an uncommon abnormality. When compared to patients without del6q23, patients with del6q23 tend to have more adverse clinical and cytogenetic profiles at baseline, which likely confer a worse prognosis as reflected by shorter TTFT compared to patients without this abnormality. Figure Disclosures Ding: Merck: Membership on an entity's Board of Directors or advisory committees, Research Funding; DTRM: Research Funding; Beigene: Membership on an entity's Board of Directors or advisory committees; alexion: Membership on an entity's Board of Directors or advisory committees; MEI Pharma: Membership on an entity's Board of Directors or advisory committees; Octapharma: Membership on an entity's Board of Directors or advisory committees; Abbvie: Research Funding; Astra Zeneca: Research Funding. Wang:Novartis: Research Funding; Innocare: Research Funding; Incyte: Research Funding. Braggio:DASA: Consultancy; Bayer: Other: Stock Owner; Acerta Pharma: Research Funding. Kay:Sunesis: Research Funding; Abbvie: Research Funding; Tolero Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Research Funding; Bristol Meyer Squib: Membership on an entity's Board of Directors or advisory committees, Research Funding; Juno Theraputics: Membership on an entity's Board of Directors or advisory committees; Dava Oncology: Membership on an entity's Board of Directors or advisory committees; Oncotracker: Membership on an entity's Board of Directors or advisory committees; Rigel: Membership on an entity's Board of Directors or advisory committees; Morpho-sys: Membership on an entity's Board of Directors or advisory committees; Cytomx: Membership on an entity's Board of Directors or advisory committees; Agios Pharma: Membership on an entity's Board of Directors or advisory committees; Acerta Pharma: Research Funding; MEI Pharma: Research Funding; Pharmacyclics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Astra Zeneca: Membership on an entity's Board of Directors or advisory committees. Kenderian:Juno: Research Funding; Gilead: Research Funding; Lentigen: Research Funding; MorphoSys: Research Funding; Sunesis: Research Funding; Kite: Research Funding; Novartis: Patents & Royalties, Research Funding; Torque: Consultancy; Humanigen: Consultancy, Patents & Royalties, Research Funding; Mettaforge: Patents & Royalties; Tolero: Research Funding; BMS: Research Funding. Parikh:Ascentage Pharma: Research Funding; Merck: Research Funding; AbbVie: Honoraria, Research Funding; AstraZeneca: Honoraria, Research Funding; TG Therapeutics: Research Funding; Pharmacyclics: Honoraria, Research Funding; GlaxoSmithKline: Honoraria; Janssen: Honoraria, Research Funding; MorphoSys: Research Funding; Genentech: Honoraria; Verastem Oncology: Honoraria.

Background: Ciltacabtagene autoleucel (cilta-cel; JNJ-68284528; LCAR-B38M CAR-T cells) is a chimeric antigen receptor T (CAR-T) cell therapy with 2 B-cell maturation antigen-targeting single-domain antibodies designed to confer avidity. In the phase 1 LEGEND-2 study in China, LCAR-B38M yielded deep, durable responses with a manageable safety profile in patients (pts) with relapsed/refractory multiple myeloma (R/R MM). The phase 1b/2 CARTITUDE-1 study (NCT03548207) is further evaluating cilta-cel in this pt population in the US. We present updated data from the phase 1b portion along with initial phase 2 data. Methods: Eligible pts (aged ≥18 y) were diagnosed with MM per International Myeloma Working Group (IMWG) criteria and had measurable disease, Eastern Cooperative Oncology Group performance status ≤1, received ≥3 prior regimens or were double-refractory to a proteasome inhibitor and immunomodulatory drug, and received an anti-CD38 antibody. After apheresis, bridging therapy was permitted. Cyclophosphamide 300 mg/m2 and fludarabine 30 mg/m2 daily for 3 d were used for lymphodepletion. A single infusion of cilta-cel at a target dose of 0.75×106 (range 0.5-1.0×106) CAR+ viable T cells/kg was administered 5-7 d after start of lymphodepletion. The primary objective of the phase 1b portion was to characterize cilta-cel safety and establish the recommended phase 2 dose; the primary objective of the phase 2 portion was to evaluate cilta-cel efficacy. Response was assessed per IMWG criteria and minimal residual disease (MRD) by next-generation sequencing. Adverse events (AEs) were graded using CTCAE v5.0. In the phase 1b portion, cytokine release syndrome (CRS) was graded by Lee et al (Blood 2014) and neurotoxicity by CTCAE v5.0; in the phase 2 portion, CRS and neurotoxicity were graded by American Society for Transplantation and Cellular Therapy (ASTCT) criteria. In this combined analysis, Lee et al and CTCAE v5.0 were mapped to ASTCT criteria for CRS and immune effector cell-associated neurotoxicity syndrome (ICANS), respectively. Results: As of the May 20, 2020 clinical cutoff, 97 pts (58.8% male; median age 61.0 y [range 43-78]) with R/R MM received cilta-cel (29 in phase 1b; 68 in phase 2). Median follow-up duration was 8.8 mo (range 1.5-20.4). Pts had received a median of 6 prior lines of therapy (range 3-18); 83.5% were penta-exposed, 87.6% were triple-refractory, 41.2% were penta-refractory, and 97.9% were refractory to last line of therapy. Overall response rate per independent review committee (primary endpoint) was 94.8% (95% CI 88.4-98.3), with a stringent complete response rate of 55.7% (95% CI 45.2-65.8), very good partial response rate of 32.0% (95% CI 22.9-42.2), and partial response rate of 7.2% (95% CI 3.0-14.3). All pts achieved a reduction in M-protein. Median time to first response was 1.0 mo (range 0.9-5.8; 80.4% ≤1.0 mo), and median time to complete response or better was 1.8 mo (range 0.9-12.5; 74.1% ≤3.0 mo); responses deepened over time (Figure). Median duration of response was not reached (NR). Of 52 MRD-evaluable pts, 94.2% were MRD-negative at 10-5. The 6-mo progression-free survival (PFS) and overall survival (OS) rates (95% CI) were 87.4% (78.9-92.7) and 93.8% (86.7-97.2), respectively; median PFS and OS were NR. Ten deaths occurred during the study; 8 were due to AEs (both related and unrelated; CRS/hemophagocytic lymphohistiocytosis, neurotoxicity, respiratory failure, sepsis, septic shock, pneumonia, lung abscess, and acute myelogenous leukemia [n=1 each]), and 2 due to progressive disease. AEs reported in >70% of pts were CRS (94.8%; grade [gr] 3/4 4.1%), neutropenia (90.7%; gr 3/4 90.7%), anemia (81.4%; gr 3/4 68.0%), and thrombocytopenia (79.4%; gr 3/4 59.8%). Median time to CRS onset was 7.0 d (range 1-12) and median duration 4.0 d (range 1-27, excluding n=1 with 97 d). CAR-T cell-related neurotoxicity was reported in 20.6% of pts (gr 3/4 10.3%). Cilta-cel CAR+ T cells showed maximum peripheral expansion at 14 d (range 9-43). Among pts with 6 mo' individual follow-up, 67% had cilta-cel CAR+ T cells below the level of quantification (2 cells/µL) in peripheral blood. Conclusions: Preliminary phase 1b/2 data from CARTITUDE-1 indicate a single low-dose infusion of cilta-cel leads to early, deep, and durable responses in heavily pretreated pts with MM with a safety profile consistent with LEGEND-2. Further investigation of cilta-cel in other MM populations is underway. Disclosures Madduri: Celgene: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria; Foundation Medicine: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Legend: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Speaking Engagement, Speakers Bureau; Kinevant: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Speaking Engagement, Speakers Bureau; GSK: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Speaking Engagement, Speakers Bureau. Berdeja:Teva: Research Funding; Bluebird: Research Funding; Bioclinica: Consultancy; Celgene: Consultancy, Research Funding; EMD Sorono: Research Funding; Kite Pharma: Consultancy; Prothena: Consultancy; Cellularity: Research Funding; Karyopharm: Consultancy; Servier: Consultancy; Legend: Consultancy; Poseida: Research Funding; Lilly: Research Funding; Acetylon: Research Funding; CURIS: Research Funding; Janssen: Consultancy, Research Funding; Genentech, Inc.: Research Funding; Glenmark: Research Funding; Takeda: Consultancy, Research Funding; BMS: Consultancy, Research Funding; Constellation: Research Funding; CRISPR Therapeutics: Consultancy, Research Funding; Vivolux: Research Funding; Abbvie: Research Funding; Amgen: Consultancy, Research Funding; Kesios: Research Funding; Novartis: Research Funding. Usmani:Celgene: Other; BMS, Celgene: Consultancy, Honoraria, Other: Speaking Fees, Research Funding; GSK: Consultancy, Research Funding; Pharmacyclics: Research Funding; Merck: Consultancy, Research Funding; Abbvie: Consultancy; Sanofi: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria, Other: Speaking Fees, Research Funding; Janssen: Consultancy, Honoraria, Other: Speaking Fees, Research Funding; SkylineDX: Consultancy, Research Funding; Seattle Genetics: Consultancy, Research Funding; Incyte: Research Funding; Array Biopharma: Research Funding; Amgen: Consultancy, Honoraria, Other: Speaking Fees, Research Funding. Jakubowiak:Adaptive, Juno: Consultancy, Honoraria; AbbVie, Amgen, BMS/Celgene, GSK, Janssen, Karyopharm: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Cohen:Celgene: Membership on an entity's Board of Directors or advisory committees; Takeda,: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; GlaxoSmithKline: Membership on an entity's Board of Directors or advisory committees; Kite Pharma: Membership on an entity's Board of Directors or advisory committees; Oncopeptides: Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: Membership on an entity's Board of Directors or advisory committees; AstraZeneca: Membership on an entity's Board of Directors or advisory committees; Genentech/Roche: Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Other: Patents/Intellectual property licensed, Research Funding. Stewart:Janssen, BMS, Sanofi-Aventis, GSK: Honoraria; Tempus, Inc., Genomics England LLC: Membership on an entity's Board of Directors or advisory committees. Hari:Amgen: Consultancy; BMS: Consultancy; GSK: Consultancy; Janssen: Consultancy; Takeda: Consultancy; Incyte Corporation: Consultancy. Htut:City of Hope Medical Center: Current Employment. Munshi:OncoPep: Consultancy, Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties; BMS: Consultancy; Janssen: Consultancy; Adaptive: Consultancy; Legend: Consultancy; Amgen: Consultancy; Karyopharm: Consultancy; Takeda: Consultancy; AbbVie: Consultancy; C4: Current equity holder in private company. Deol:Novartis: Consultancy; Kite, a Gilead Company: Consultancy. Lesokhin:BMS: Consultancy, Honoraria, Research Funding; Genentech: Research Funding; Janssen: Research Funding; Juno: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Serametrix Inc.: Patents & Royalties; GenMab: Consultancy, Honoraria. Singh:Janssen: Current Employment. Zudaire:Janssen: Current Employment. Yeh:Janssen: Current Employment. Allred:Janssen: Current Employment. Olyslager:Janssen: Current Employment. Banerjee:Janssen: Current Employment. Goldberg:Johnson & Johnson: Current Employment, Current equity holder in publicly-traded company. Schecter:Janssen: Current Employment. Jackson:Janssen: Current Employment; Memorial Sloan Kettering Cancer Center: Consultancy. Deraedt:Janssen: Current Employment, Current equity holder in publicly-traded company. Zhuang:Janssen: Current Employment. Infante:Janssen: Current Employment. Geng:Legend Biotech USA Inc.: Current Employment. Wu:Legend Biotech USA Inc.: Current Employment. Carrasco:Legend Biotech USA Inc.: Current Employment. Akram:Legend Biotech USA Inc.: Current Employment. Hossain:Legend Biotech USA Inc.: Current Employment. Rizvi:Legend Biotech USA Inc.: Current Employment. Fan:Legend Biotech USA Inc.: Current Employment. Jagannath:BMS, Janssen, Karyopharm, Legend Biotech, Sanofi, Takeda: Consultancy. Lin:Kite, a Gilead Company: Consultancy, Research Funding; Janssen: Consultancy, Research Funding; Merck: Research Funding; Legend BioTech: Consultancy; Juno: Consultancy; Bluebird Bio: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Novartis: Consultancy; Vineti: Consultancy; Takeda: Research Funding; Gamida Cells: Consultancy; Sorrento: Consultancy, Membership on an entity's Board of Directors or advisory committees. Martin:AMGEN: Research Funding; Seattle Genetics: Research Funding; Janssen: Research Funding; GSK: Consultancy; Sanofi: Research Funding.

Background Maintenance therapy improves PFS in NDMM pts. Additional active, well-tolerated treatment options that are suitable for long-term administration are required. The international, multicenter, double-blind, placebo-controlled, phase 3 TOURMALINE-MM4 trial (NCT02312258) of the oral PI ixazomib as maintenance therapy post-induction in non-transplant NDMM pts met its primary endpoint of PFS. Ixazomib demonstrated a significant and clinically meaningful benefit vs placebo, with a manageable and well-tolerated toxicity profile. Feasible, tolerable options for long-term therapy are particularly important in this setting, as pts are often elderly and/or frail. We report herein a subgroup analysis of TOURMALINE-MM4 according to age and frailty status. Methods Pts who achieved ≥partial response (PR) after 6-12 months of standard-of-care induction therapy were randomized 3:2 to ixazomib or placebo maintenance for up to 24 months. The sum of 4 components - age (<75 vs 75-80 vs >80 years; score 0 vs 1 vs 2), the Katz Index of Independence in Activities of Daily Living (ADL; >4 vs ≤4, score 0 vs 1), the Lawton Instrumental ADL Scale (>5 vs ≤5, score 0 vs 1), and the Charlson Comorbidity Index (≤1 vs ≥2, score 0 vs 1) - was used to classify pts as fit (total score: 0), unfit (score: 1), or frail (score: ≥2). Analyses of the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 and MY20 modules were conducted to evaluate the effects of treatment on QoL within subgroups defined by frailty status and age. Results In the ixazomib (n=425) vs placebo (n=281) arms, there were similar proportions of pts aged <65, 65-74, and ≥75 years and of pts classified as fit, unfit, and frail (Table 1). Baseline disease and treatment characteristics were generally balanced in ixazomib vs placebo pts across the different age and frailty groups, with some numerical differences observed. In pts aged <65 years, higher rates of International Staging System (ISS) stage III disease and fit pts and a lower rate of complete (CR) or very good partial (VGPR) response post-induction were seen (Table 1). Across frailty groups, a higher rate of CR or VGPR was seen in fit pts, a lower rate of ISS stage III disease was seen in unfit pts, and a higher rate of ISS stage III disease and a lower rate of CR or VGPR were seen in frail pts (Table 1). PFS benefit with ixazomib vs placebo was seen across age groups, with hazard ratios (HRs) of 0.576 (95% confidence interval [CI] 0.299-1.108, p=0.095, median 11.0 vs 9.3 months) in pts aged <65 years, 0.615 (95% CI 0.467-0.810, p<0.001, median 17.9 vs 9.3 months) in pts aged 65-74, and 0.740 (95% CI 0.537-1.019, p=0.064, median 16.7 vs 10.2 months) in pts aged ≥75 years. HRs for time to progression (TTP) were similar to those for PFS. PFS benefit with ixazomib vs placebo was also seen across frailty groups (Figure), with similar HRs for TTP. Rates of grade ≥3 treatment-emergent adverse events (TEAEs), serious TEAEs, and discontinuation due to TEAEs were higher or similar with ixazomib vs placebo across age and frailty subgroups (Table 2). Rates were generally somewhat higher in older age groups and in unfit/frail pts in both arms; nevertheless, rates of discontinuation due to TEAEs across groups were <20%, even in pts aged ≥75 years and frail pts (Table 2). With ixazomib, rates of common gastrointestinal TEAEs were similar across age groups; rash and liver impairment appeared less common and peripheral neuropathy more common in older pts (Table 2). Covariate-adjusted changes in QoL subscales from baseline were estimated at each cycle using repeated measures linear mixed models stratified by frailty status. In all frailty groups, the mean changes in each treatment arm were small over time (<10 points on a 0-100 scale) and similar between arms, indicating that continued treatment with ixazomib vs placebo maintenance did not adversely affect pts' QoL. Analyses by age were generally consistent with the results by frailty. Conclusions Ixazomib as post-induction maintenance therapy in non-transplant NDMM pts results in PFS benefits vs placebo regardless of age or frailty status. Ixazomib appeared generally well tolerated across groups, with TEAE rates in both arms generally elevated in elderly/frail vs younger/fit pts. Ixazomib is a feasible and effective maintenance option for prolonging PFS across this heterogeneous pt population. Disclosures Bringhen: Takeda: Consultancy; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Honoraria; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Karyopharm: Membership on an entity's Board of Directors or advisory committees. Vorog:Millennium Pharmaceuticals, Inc., a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Current Employment. Labotka:Millennium Pharmaceuticals, Inc., a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Current Employment. Wang:Millennium Pharmaceuticals, Inc., a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Current Employment. Cherepanov:Millennium Pharmaceuticals, Inc., a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Current Employment. Cain:Millennium Pharmaceuticals, Inc., a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Current Employment. Manne:Millennium Pharmaceuticals, Inc., a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Current Employment. Dimopoulos:Celgene: Honoraria; Janssen: Honoraria; Takeda: Honoraria; Bristol-Myers Squibb: Honoraria; Beigene: Honoraria; Amgen: Honoraria. OffLabel Disclosure: Use of the oral proteasome inhibitor ixazomib as maintenance therapy in patients with newly diagnosed multiple myeloma not undergoing stem cell transplantation

Introduction: With a median overall survival (OS) measured in months, successful treatment of Richter's transformation (RT) of chronic lymphocytic leukemia (CLL) to diffuse large B-cell lymphoma (DLBCL) remains a major unmet medical need. While targeted agents, such as Bruton tyrosine kinase inhibitor (BTKi) monotherapy, have greatly improved outcomes for patients (pts) with CLL and some B-cell lymphomas, available BTKi therapies have been ineffective for RT, as well as for large cell transformation of indolent B-cell lymphomas and relapsed/refractory (r/r) DLBCL, which rapidly develop mechanisms of resistance by activation of downstream targets of BTKi or upregulation of alternative/parallel pathways. Focusing on a synthetic lethality approach via in vitro and in vivo studies, we discovered that concurrent inhibition of BTK & mTOR targets plus an IMiD synergistically kill malignant B-cells. DTRM-555 is an optimized oral triple combination of a novel irreversible BTKi DTRMWXHS-12 (DTRM-12), everolimus (EV) and pomalidomide (POM). This once daily therapy was tested in a stepwise, phase I, multicenter study in pts with the greatest unmet medical needs. Here we present results for this novel combination therapy in pts with RT, and r/r DLBCL. Methods: We conducted a phase I (3+3 design), first in human trial exploring DTRM-555 in adult pts with B-cell lymphomas with no available standard therapies (NCT02900716) at 6 US cancer centers. Our goal was to determine the optimal dose for DTRM-555. In phase Ia, an MTD was not reached for DTRM-12 monotherapy; In phase Ib and expansion cohorts, we evaluated double (DTRM-12/EV at 200mg/5mg or 300mg/5mg) and triple combinations (DTRM-12/EV/POM at 200mg/5mg/2mg or 300mg/5mg/2mg) administered once daily for 21 days of a 28-day cycle, until disease progression or unacceptable toxicity. The primary endpoint was safety and the dose limiting toxicity (DLT) period was cycle 1 (28 days). Secondary endpoints included overall response rate (ORR; Cheson 2014), duration of response (DOR), and DTRM-12 pharmacokinetics. The trial began on 9/27/2016 and completed enrollment with evaluable follow-up data cut-off date on 08/06/2020. Results: 39 pts were enrolled and treated, including 24 with RT (n=12) or r/r DLBCL (n=12). The safety analyses included all 39 pts treated with combination therapies while efficacy analyses were focused on RT and r/r DLBCL. Baseline characteristics (n=39): 66% male, median age 71 years (range 43-94) and 94% white. For the entire study cohort, median number of prior therapies was 3 (range 1-10), 49% had been treated with prior BTKi monotherapy,13% prior CAR-T or stem cell transplant (SCT) and 59% ≥1 prior small molecule targeted agent. For pts with RT and r/r DLBCL (n=24), median prior therapies were 5 (range 1-10) and 2 (range 10), respectively. Table 1 summarizes prior therapies for the 24 RT and r/r DLBCL pts. Table 2 describes Grade 3 and 4 related AEs for 39 pts treated with the combination therapies. AEs were manageable and similar to known AEs for BTKi, EV or POM, with a total of 4 DLTs observed with combination therapies. The most common AEs were hematological events; specifically, thrombocytopenia, neutropenia, and anemia. The MTD of DTRM-555 was determined to be DTRM-12 200mg, EV 5mg, & POM 2mg. For 11 evaluable RT pts, ORR was 45% (1 CR, 4 PR); 1 RT pt has not undergone first response assessment. For 10 evaluable DLBCL pts, ORR was 60% (2 CR, 4 PR). Responders with RT or r/r DLBCL have durable responses (Figure 1). Kaplan Meier estimated median duration of response for RT and DLBCL pts was 15 months as of the cut-off. Dose dependent DTRM-12 drug plasma levels were observed in all arms with minimal inter-pt variability. Conclusions: This clinical trial met its primary endpoint. The once-daily oral triple combination therapy DTRM-555 has an acceptable safety profile. Encouraging clinical activity was observed in several high-risk, multi-refractory pts with RT (median 5 prior therapies, ORR 45%) or r/r DLBCL (median 2 prior therapies, ORR 60%), including pts previously treated with targeted therapies, cellular therapies, checkpoint inhibitors and other experimental agents. A phase II US expansion study is underway targeting pts with RT, r/r DLBCL, r/r transformed follicular lymphoma and BTKi/BCL2 inhibitor exposed r/r CLL pts. Disclosures Mato: Adaptive: Consultancy, Research Funding; TG Therapeutics: Consultancy, Other: DSMB, Research Funding; AbbVie: Consultancy, Research Funding; AstraZeneca: Consultancy, Research Funding; BeiGene: Consultancy; LOXO: Consultancy, Research Funding; Janssen: Consultancy, Research Funding; Genentech: Consultancy, Research Funding; Pharmacyclics LLC, an AbbVie Company: Consultancy, Research Funding. Schuster:AlloGene, AstraZeneca, BeiGene, Genentech, Inc./ F. Hoffmann-La Roche, Juno/Celgene, Loxo Oncology, Nordic Nanovector, Novartis, Tessa Therapeutics: Consultancy, Honoraria; Novartis, Genentech, Inc./ F. Hoffmann-La Roche: Research Funding. Ding:DTRM: Research Funding; Astra Zeneca: Research Funding; Abbvie: Research Funding; Octapharma: Membership on an entity's Board of Directors or advisory committees; MEI Pharma: Membership on an entity's Board of Directors or advisory committees; alexion: Membership on an entity's Board of Directors or advisory committees; Beigene: Membership on an entity's Board of Directors or advisory committees; Merck: Membership on an entity's Board of Directors or advisory committees, Research Funding. Brander:Tolero: Research Funding; NCCN: Other; Teva: Consultancy, Honoraria; Novartis: Consultancy, Other; NCCN: Other; Verastem: Consultancy, Honoraria, Other, Research Funding; TG Therapeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other, Research Funding; Pfizer: Consultancy, Other; Pharmacyclics LLC, an AbbVie Company: Consultancy, Honoraria, Other, Research Funding; MEI Pharma: Other, Research Funding; Juno/Celgene/BMS: Other, Research Funding; Genentech: Consultancy, Honoraria, Other, Research Funding; DTRM: Other, Research Funding; AstraZeneca: Consultancy, Honoraria, Other, Research Funding; BeiGene: Other, Research Funding; Ascentage: Other, Research Funding; ArQule: Consultancy, Other, Research Funding; AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other, Research Funding; Tolero: Research Funding; Teva: Consultancy, Honoraria; Novartis: Consultancy, Other. Tun:Bristol-Myers Squibb: Research Funding; Celgene: Research Funding; Mundipharma: Research Funding; Curis: Research Funding; TG Therapeutics: Research Funding; Acrotech: Research Funding; DTRM Biopharma: Research Funding. He:DTRM Biopharma LLC: Current Employment. Kearney:DTRM Biopharma LLC: Current Employment. Gui:DTRM Biopharma LLC: Current Employment. McKinlay:DTRM Biopharma LLC: Current Employment. Roeker:American Society of Hematology: Research Funding; AbbVie: Other: spouse with minority ownership interest ; Abbott Laboratories: Other: spouse with minority ownership interest . Huntington:Pharmacyclics: Honoraria; Novartis: Consultancy; Genentech: Consultancy; DTRM: Research Funding; AbbVie: Consultancy; Astrazeneca: Honoraria; Bayer: Consultancy, Honoraria; Celgene: Consultancy, Research Funding; TG Therapeutics: Research Funding.

AbstractBackgroundLarge cohort studies provide conflicting evidence regarding the prognostic value of early repolarization pattern (ERP) in the general population, complicated by the complex or heterogeneous definitions of ERP applied in different studies.HypothesisWe hypothesized that ERP was associated with increased cardiovascular risk with the definition of ERP recommended by the expert consensus statements.MethodsA total of 13673 middle‐aged subjects from the prospective, population‐based Atherosclerosis Risk in Communities (ARIC) study were included in this analysis. Cox models were used to estimate the hazard ratios (HRs) adjusted for possible confounding factors. ERP was defined as ST‐segment elevation ≥0.1mV at the end of the QRS or J wave on the QRS downstroke in two or more contiguous leads.ResultsCompared with those without ERP, subjects with ERP had a significantly increased risk of developing sudden cardiac death (SCD) (HR, 1.48; 95% CI, 1.08–2.04) and death from coronary heart disease (CHD) (HR, 1.45; 95% CI, 1.10–1.92) after a median follow‐up of 20.1 years. ERP was significantly predictive of SCD in females, whites, younger people, and subjects with relatively low cardiovascular risk. ERP with ST‐segment elevation appeared to indicate poor cardiovascular outcomes. ERP was associated with an absolute risk increase of 93.3 additional SCDs per 100 000 person‐years.ConclusionsOur findings suggest that ERP was an independent predictor of SCD and CHD death in the middle‐aged biracial population.