Kay, Neil E.

Abstract Background: The ECOG-ACRIN randomized phase 3 clinical trial E1912 established ibrutinib-rituximab (IR) as the standard of care for CLL patients <= 70 years in the frontline setting by improving the progression free (PFS) and overall survival (OS) compared to previous standard chemo-immunotherapy with fludarabine, cyclophosphamide and rituximab (FCR) (Shanafelt et al. NEJM 2019). Quality of life (QOL) was an important secondary endpoint on this trial comparing continuous (IR) vs time-limited (FCR) therapy due to the differing profile of treatment-related toxicities over the short and long-term. E1912 patient-reported outcomes (PROs) results are presented here. Methods: Patients enrolled on E1912 completed the Functional Assessment of Cancer Therapy-General (FACT-G) and Leukemia subscale at randomization (baseline), 3, 6, and 12 months post-randomization, and every 6 months for 2 years regardless of disease status. The primary outcome was the 31-item FACT-Leukemia Trial Outcome Index (FACT-Leu TOI), calculated by summing items from the FACT-G physical wellbeing (PWB), functional well-being (FWB), and leukemia subscales (score range: 0-124). The primary endpoint was defined as the difference in FACT-Leu TOI change scores from randomization to 12 months (at response evaluation) between patients treated with continuous therapy Arm A (IR) vs time-limited therapy Arm B (FCR). Mean change scores from baseline to each time point were calculated using all cases with data at baseline and the corresponding time point. Comparisons between treatment arms were performed using two-sample t tests. Linear mixed effects models were used to estimate the trajectories of PRO scores. Results: PRO data was extracted on 3/8/2021. PRO data was provided at baseline and 12 months for 233/354 (65.8%) patients on the IR arm and 118/175 (67.4%) patients on the FCR arm. At enrollment, there were no significant differences in the baseline FACT-Leu TOI scores (mean ± SE) between the two arms: IR (93.27 ± 1.03) vs FCR (92.68 ± 1.38; p=0.73). The FACT-Leu TOI score improved from baseline to 12 months in both arms (Table 1 and Figure 1). The change scores from baseline to 12 months, the primary outcome, were not significantly different between IR (7.59 ± 1.09) vs FCR (8.22 ± 1.44; p=0.73). Change in FACT-Leu TOI from baseline to 3 months was 5.77 ± 0.77 and 4.06 ± 1.18 (p=0.22); and from baseline to 6 months was 6.87 ± 0.87 and 8.01 ± 1.44 (p=0.50) in the IR and FCR arms, respectively. After the first 6 months of treatment, the improvement in FACT-Leu TOI scores was maintained in both treatment arms. There was no significant difference in total FACT-Leu TOI score in the continuous therapy (IR) vs time-limited therapy (FCR) arms over the first 36 months post registration. Analysis of FACT subscales showed PWB improved in the IR arm (0.37 ± 0.22) and declined in the FCR arm (-0.92 ± 0.39) from baseline to 3 months (p=0.004 for difference in PWB change between arms) but there was no significant difference between the two arms for change in PWB scores from baseline to 6 and 12 months. There were no significant differences between the two arms for change in FWB and FACT-Leu subscales from baseline to 3, 6 and 12 months. Conclusions: QOL improves in CLL patients age 70 and younger when treated in the frontline setting with IR or FCR. The improvement in QOL is maintained during continuous therapy with ibrutinib and there is no significant decline in QOL over time. Given the improvement in PFS and OS with IR over FCR seen in E1912, the results of this QOL analysis support the use of frontline ibrutinib in previously untreated younger CLL patients. Acknowledgement: This study was conducted by the ECOG-ACRIN Cancer Research Group (Peter J. O'Dwyer, MD and Mitchell D. Schnall, MD, PhD, Group Co-Chairs) and supported by the National Cancer Institute of the National Institutes of Health under award numbers: U10CA180794, U10CA180820, UG1CA189863, UG1CA190140, UG1CA232760, UG1CA233180, UG1CA233230, UG1CA233253, UG1CA233277, UG1CA233290, UG1CA233339, UG1CA189859, UG1CA233332. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. Figure 1 Figure 1. Disclosures Kay: Oncotracker: Membership on an entity's Board of Directors or advisory committees; CytomX Therapeutics: 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; Tolero Pharmaceuticals: Research Funding; Acerta Pharma: Research Funding; Behring: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees, Research Funding; TG Therapeutics: Research Funding; AstraZeneca: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Juno Therapeutics: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Agios Pharm: Membership on an entity's Board of Directors or advisory committees; Rigel: Membership on an entity's Board of Directors or advisory committees; Dava Oncology: Membership on an entity's Board of Directors or advisory committees; Morpho-sys: Membership on an entity's Board of Directors or advisory committees; Targeted Oncology: Membership on an entity's Board of Directors or advisory committees; MEI Pharma: Research Funding; Sunesis: Research Funding; Genentech: Research Funding; Bristol Meyer Squib: Membership on an entity's Board of Directors or advisory committees, Research Funding. O'Brien: Amgen, Astellas, Celgene, GlaxoSmithKline, Janssen Oncology, Aptose Biosciences Inc., Vaniam Group LLC, AbbVie, Alexion, Verastem, Juno Therapeutics, Vida Ventures, Autolus, Johnson and Johnson, Merck, Bristol Myers Squibb, NOVA Research Company, Eli Lill: Consultancy; Kite, Regeneron, Acerta, Caribou, Gilead, Pharmacyclics, TG Therapeutics, Pfizer, Sunesis: Research Funding. Coutre: Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Pharmacyclics: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; AbbVie: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; AstraZeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees; Beigene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Data Safety Monitoring Committee, Research Funding; Genentech: Consultancy, Membership on an entity's Board of Directors or advisory committees; Acerta: Other: Data Safety Monitoring Committee, Research Funding. Barr: AstraZeneca: Consultancy; Gilead: Consultancy; Janssen: Consultancy; Genentech: Consultancy; Beigene: Consultancy; Bristol Meyers Squibb: Consultancy; Seattle Genetics: Consultancy; TG Therapeutics: Consultancy; Morphosys: Consultancy; Abbvie/Pharmacyclics: Consultancy. Cashen: Secura Bio, ADC Therapeutics: Consultancy. Mato: Adaptive Biotechnologies: Consultancy, Research Funding; DTRM BioPharma: Consultancy, Research Funding; Johnson and Johnson: Consultancy, Research Funding; Acerta/AstraZeneca: Consultancy, Research Funding; Sunesis: Consultancy, Research Funding; AstraZeneca: Consultancy; BeiGene: Consultancy, Research Funding; Genentech: Consultancy, Research Funding; AbbVie: Consultancy, Research Funding; LOXO: Consultancy, Research Funding; MSKCC: Current Employment; Pharmacyclics LLC, an AbbVie Company: Consultancy, Research Funding; TG Therapeutics: Consultancy, Other: DSMB, Research Funding; Nurix: Research Funding; Janssen: Consultancy, Research Funding; Genmab: Research Funding. Erba: AbbVie Inc; Agios Pharmaceuticals Inc; Astellas; Bristol Myers Squibb; Celgene, a Bristol Myers Squibb company; Daiichi Sankyo Inc; Genentech, a member of the Roche Group; GlycoMimetics Inc; Incyte Corporation; Jazz Pharmaceuticals Inc; Kura Oncology; Nov: Other: Advisory Committee; AbbVie Inc: Other: Independent review committee; AbbVie Inc; Agios Pharmaceuticals Inc; ALX Oncology; Amgen Inc; Daiichi Sankyo Inc; FORMA Therapeutics; Forty Seven Inc; Gilead Sciences Inc; GlycoMimetics Inc; ImmunoGen Inc; Jazz Pharmaceuticals Inc; MacroGenics Inc; Novartis; PTC Therapeutics: Research Funding; AbbVie Inc; Agios Pharmaceuticals Inc; Bristol Myers Squibb; Celgene, a Bristol Myers Squibb company; Incyte Corporation; Jazz Pharmaceuticals Inc; Novartis: Speakers Bureau. Stone: Onconova: Consultancy; AbbVie: Consultancy; Boston Pharmaceuticals: Consultancy; Bristol Myers Squibb: Consultancy; Gemoab: Membership on an entity's Board of Directors or advisory committees; Elevate Bio: Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Research Funding; Jazz: Consultancy; Syros: Membership on an entity's Board of Directors or advisory committees; Syndax: Membership on an entity's Board of Directors or advisory committees; Agios: Consultancy, Research Funding; Takeda: Consultancy; BerGen Bio: Membership on an entity's Board of Directors or advisory committees; Astellas: Membership on an entity's Board of Directors or advisory committees; Foghorn Therapeutics: Consultancy; Innate: Consultancy; Janssen: Consultancy; GlaxoSmithKline: Consultancy; Amgen: Membership on an entity's Board of Directors or advisory committees; Arog: Consultancy, Research Funding; Actinium: Membership on an entity's Board of Directors or advisory committees; Syntrix/ACI: Membership on an entity's Board of Directors or advisory committees; Aprea: Consultancy; Celgene: Consultancy; Macrogenics: Consultancy. Litzow: Actinium: Research Funding; Amgen: Research Funding; AbbVie: Research Funding; Pluristem: Research Funding; Jazz: Other: Advisory Board; Omeros: Other: Advisory Board; Astellas: Research Funding; Biosight: Other: Data monitoring committee. Tallman: NYU Grand Rounds: Honoraria; Kura: Membership on an entity's Board of Directors or advisory committees; Syros: Membership on an entity's Board of Directors or advisory committees; Innate Pharma: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Biosight: Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees; Jazz Pharma: Membership on an entity's Board of Directors or advisory committees; Oncolyze: Membership on an entity's Board of Directors or advisory committees; KAHR: Membership on an entity's Board of Directors or advisory committees; Orsenix: Membership on an entity's Board of Directors or advisory committees; Daiichi-Sankyo: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees; Amgen: Research Funding; Rafael Pharmaceuticals: Research Funding; Glycomimetics: Research Funding; Biosight: Research Funding; Orsenix: Research Funding; Abbvie: Research Funding; Mayo Clinic: Honoraria; UC DAVIS: Honoraria; Northwell Grand Rounds: Honoraria; NYU Grand Rounds: Honoraria; Danbury Hospital Tumor Board: Honoraria; Acute Leukemia Forum: Honoraria; Miami Leukemia Symposium: Honoraria; New Orleans Cancer Symposium: Honoraria; ASH: Honoraria; NCCN: Honoraria. Shanafelt: Genentech, Pharmacyclics: Research Funding. Wagner: Eli Lilly, Johnson & Johnson: Other: Spouse, previously held individual stocks;; Celgene-BMS: Consultancy, Membership on an entity's Board of Directors or advisory committees; Athenex Inc: Consultancy.

Abstract INTRODUCTION Sparse data exist regarding I+V in an off-trial setting, particularly in patients (pts) with progression of disease on either I or V as single agent treatment. The 1-year overall survival (OS) rates with V monotherapy following I range from 75%-91% (Eyre et al, BJH 2019; Jones et al, Lancet Oncol 2018); however, longer-term follow-up of these or other patient cohorts treated with V after I has not yet been reported. Effective options in double-refractory pts are lacking when a clinical trial is not feasible. Here, we report our experience with I+V in these patient groups. METHODS After IRB approval, we reviewed the records of pts seen at Mayo Clinic (between 4/2012-1/2021) who received I+V therapy off-trial for CLL progression. Pts treated with I+V for Richter's transformation were excluded. Time to next treatment (TTNT) was measured from I+V treatment start date to the date of next treatment start or last known treatment status with death as a competing risk. OS was measured from I+V start date until date of death or when the patient was last known alive; OS was analyzed using the Kaplan-Meier method and Cox proportional hazards model. RESULTS Thirty-three pts with progressive CLL were treated with I+V (median duration 13.3 months [95% CI: 7.1 months-not estimable (NE)]). The median age was 70 years (range 47-86), 6 (18%) were women, and 20 (65%) had del(17p) or TP53 mutation. The median number of prior lines of therapy was 3 (range 1-15). Additional characteristics at the time of I+V start are shown in Table 1. Median follow-up from start of I+V was 23.8 months. Among 22 pts with prior progression on I only (V-naïve), the median duration of I+V was 14.8 months (95% CI 7.6 months-NE). The median duration on either I or V from the start of combination was 20.3 months (95% CI 8.3 months-NE). The median TTNT was 25.1 months (Figure 1A). Four pts proceeded to cellular therapy (alloSCT [n=3], CAR-T [n=1]) while on I+V. Next therapy (n=9) consisted of Richter transformation treatment (n=2), chemotherapy plus continued I+V (n=1), anti-CD20 plus continued I+V (n=1), duvelisib + I (n=1), TP-0903 + I (n=1), reintroduction of I at disease progression after previously stopping I during I+V therapy (n=1), and reintroduction of I (n=1) or V (n=1) at disease progression after previously stopping I+V. Of 9 pts who did not receive subsequent therapy, 4 pts remain on I+V (median duration 16.4 months), 4 pts continued V after discontinuing I (median duration on V from start of I+V was 21.5 months), and 1 pt discontinued I+V following a second cancer diagnosis and died without receiving additional CLL-directed treatment. Eleven pts received I+V in the double-refractory setting; 9 pts had prior disease progression on sequential I then V and 2 pts had prior disease progression on sequential V then I. The median duration of I+V was 7.5 months (95% CI 4.3 months-NE), and the median duration of either agent from I+V start was 10.8 months (95% CI 7.1 months-NE). The median TTNT was 14.0 months (Figure 1A). Eight pts required additional treatment, consisting of PI3K inhibitor (n=2), anti-CD20 added to I+V (n=1), CAR-T (n=1), anti-CD20 with (n=1) or without (n=1) bendamustine added to continued I, and Richter transformation treatment (n=2). One pt continues I+V (17.4 months ongoing) without further treatment. Two pts died from disease progression without receiving additional treatment. The median OS of all 33 pts was 27.4 months (95% CI 25.9 months-NE; Figure 1B). The median OS of the 22 pts with prior progression on I (V-naïve) was 47.1 months (95% CI 27.7 months-NE), and the median OS of the 11 pts with prior progression on I and V separately was 27.0 months (95% CI 15.5 months-NE). In univariate analyses, prior progression on V was a predictor of shorter OS (HR=3.9; 95% CI 1.4-11.2; p=0.01). CONCLUSIONS Combination I+V therapy in heavily pre-treated CLL pts who have disease progression after I provides durable benefit with a median OS approaching 4 years. In the double-refractory setting, repurposing both drugs as combination I+V therapy can be a useful strategy, despite the short-term disease control, for pts where clinical trial options are limited or not available. Further examination of these approaches in larger cohorts and understanding the operative resistance mechanisms in pts with double-refractory disease are key next studies. Figure 1 Figure 1. Disclosures Ding: Octapharma: 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. Chanan-Khan: BeiGene, Jansen, Ascentage: Honoraria; Ascentage, Starton, Cellectar, NonoDev, Alpha2 Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; Alpha2 Pharmaceuticals: Patents & Royalties: Tabi; Ascentage: Research Funding; Cellectar: Current equity holder in publicly-traded company; Alpha2 Pharmaceuticals, NonoDev, Starton: Current holder of stock options in a privately-held company; BieGene, Jansen, Ascentage: Consultancy. Kenderian: Humanigen, Inc.: Consultancy, Honoraria, Research Funding. Wang: TG Therapeutics: Membership on an entity's Board of Directors or advisory committees; MorphoSys: Research Funding; Novartis: Research Funding; LOXO Oncology: Membership on an entity's Board of Directors or advisory committees, Research Funding; Genentech: Research Funding; Incyte: Membership on an entity's Board of Directors or advisory committees, Research Funding; InnoCare: Research Funding; Eli Lilly: Membership on an entity's Board of Directors or advisory committees. Ailawadhi: Pharmacyclics: Consultancy, Research Funding; Xencor: Research Funding; Janssen: Consultancy, Research Funding; Cellectar: Research Funding; Sanofi: Consultancy; BMS: Consultancy, Research Funding; GSK: Consultancy, Research Funding; Ascentage: Research Funding; Medimmune: Research Funding; Karyopharm: Consultancy; Amgen: Consultancy, Research Funding; Beigene: Consultancy; AbbVie: Consultancy; Takeda: Consultancy; Genentech: Consultancy. Koehler: AbbVie: Membership on an entity's Board of Directors or advisory committees; TG Therapeutics: Membership on an entity's Board of Directors or advisory committees. Kay: AstraZeneca: Membership on an entity's Board of Directors or advisory committees; Dava Oncology: Membership on an entity's Board of Directors or advisory committees; Targeted 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; Juno Therapeutics: Membership on an entity's Board of Directors or advisory committees; Genentech: Research Funding; Celgene: 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; TG Therapeutics: Research Funding; Agios Pharm: Membership on an entity's Board of Directors or advisory committees; Sunesis: Research Funding; Rigel: Membership on an entity's Board of Directors or advisory committees; Acerta Pharma: Research Funding; CytomX Therapeutics: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees, Research Funding; Morpho-sys: Membership on an entity's Board of Directors or advisory committees; Oncotracker: Membership on an entity's Board of Directors or advisory committees; MEI Pharma: Research Funding; Behring: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Tolero Pharmaceuticals: Research Funding. Parikh: Pharmacyclics, MorphoSys, Janssen, AstraZeneca, TG Therapeutics, Bristol Myers Squibb, Merck, AbbVie, and Ascentage Pharma: Research Funding; Pharmacyclics, AstraZeneca, Genentech, Gilead, GlaxoSmithKline, Verastem Oncology, and AbbVie: Membership on an entity's Board of Directors or advisory committees. OffLabel Disclosure: Combination ibrutinib and venetoclax in patients with relapsed CLL.

Abstract Introduction: Chronic lymphocytic leukemia (CLL) is characterized by multiple copy number alterations (CNA) and mutations that are central to disease pathogenesis, prognosis, risk-stratification, and identification of response or resistance to therapies. Fluorescence in situ hybridization (FISH) is gold standard in the clinical laboratory for detecting prognostic CNAs in CLL (e.g. deletion 17p13 (del(17p), deletion 11q23 (del(11q), deletion 13q14 (del(13q), and trisomy 12). Most clinical FISH assays have high specificity and sensitivity, but the technique can detect a limited number of alterations per assay. Importantly, next-generation sequencing (NGS) techniques have become more readily available for clinical applications and are increasingly being used for screening not only mutations, but also copy number abnormalities in multiple genes and chromosomal regions of interest in hematologic malignancies. Here, we evaluated the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) using a custom targeted NGS assay for detecting common prognostic chromosomal alterations in CLL and high-count monoclonal B-cell lymphocytosis (MBL), the precursor to CLL. Methods : We designed a SureSelect DNA targeted sequencing panel, covering all exons of 59 recurrently CLL mutated genes and additional amplicons across regions affected by clinically relevant CNAs. All CLL (N=534) and MBL (N=162) patients had pre-treatment peripheral blood mononuclear cells (PBMC) collected within two years of diagnosis. DNA was extracted in cases with purity >80% of CD5+/CD19+ cells. Clinical FISH data was available within 100 days of NGS in all untreated CLL and MBL cases. PatternCNV was used to detect clinically relevant CNAs in chromosomes 11, 12, 13 and 17. We performed a principal component analysis on the CNA calls, excluding chromosomes 11, 12, 13, and 17 to identify clusters of samples. Each cluster was then independently rerun with PatternCNV and the results from chromosomes 11, 12, 13, and 17 were extracted and further analyzed. We excluded samples with low tumor metrics identified by FISH (less than 20% of cells with del(17p), del(11q), trisomy 12 and del(13q)). Results: We sequenced a total of 696 patients of whom 162 were MBL and 534 were untreated CLL. The most commonly mutated genes were NOTCH1 (11.0%), TP53 (8.7%), SF3B1 (7.7%), ATM (4.1%), and CHD2 (3.8%). Based on CNA analyses from the NGS data, we identified 59 (9.1%) individuals with del(17p), 88 (13.4%) individuals with del(11q), 128 (20.0%) individuals with trisomy 12, and 329 (53.0%) individuals with del(13q). All 696 individuals had FISH panels conducted, with 39 (5.6%) individuals with del(17p), 68 (9.8%) individuals with (11q), 119 (17.1%) with trisomy 12, and 295 (42.4%) with del(13q). When we compared our CNA analyses with the FISH data, we found high concordance 95.0% for del(17p), 92.7% del(11p), 94.3% for trisomy 12, and 88.2% for del(13q). For del(17p) we found a sensitivity of 93.9%, specificity of 95.4%, PPV of 52.5%, and NPV of 99.7%. Del(11q) revealed a sensitivity of 88.1%, specificity of 94.0%, PPV of 59.1%, and NPV 98.8%. We found a sensitivity of 93.8%, specificity of 95.6%, PPV 82.0%, and NPV of 98.6% for trisomy 12 and for del(13q) we found a sensitivity of 92.6%, specificity of 90.9%, PPV of 91.7%, and NPV of 93.8%. We found lower PPVs in del(17p) and del(11q) likely due to lower prevalence of these chromosomal abnormalities. Conclusion: Here we show a high sensitivity, specificity, and NPV when comparing targeted sequencing with FISH. FISH panel testing is widely used in clinical practice to characterize highly prognostic chromosomal abnormalities in CLL. Comprehensive genetic profiling with NGS has become increasingly important in the work up of hematologic malignancies and provides additional prognostic and predictive information, including clinically relevant mutations such as TP53, SF3B1, and NOTCH1, tumor mutation load and mutations associated with resistance to chemo-immunotherapy and targeted therapies, such as BTK or BCL2 inhibitors, that FISH cannot offer. We show that NGS can infer clinically relevant CNA in cases without FISH testing while also providing additional clinically relevant information. Figure 1 Figure 1. Disclosures Cerhan: Regeneron Genetics Center: Other: Research Collaboration; Celgene/BMS: Other: Connect Lymphoma Scientific Steering Committee, Research Funding; NanoString: Research Funding; Genentech: Research Funding. Parikh: Pharmacyclics, MorphoSys, Janssen, AstraZeneca, TG Therapeutics, Bristol Myers Squibb, Merck, AbbVie, and Ascentage Pharma: Research Funding; Pharmacyclics, AstraZeneca, Genentech, Gilead, GlaxoSmithKline, Verastem Oncology, and AbbVie: Membership on an entity's Board of Directors or advisory committees. Kay: Genentech: Research Funding; MEI Pharma: Research Funding; Sunesis: Research Funding; Acerta Pharma: Research Funding; Abbvie: Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees; AstraZeneca: 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; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Tolero Pharmaceuticals: Research Funding; 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 Therapeutics: Membership on an entity's Board of Directors or advisory committees; TG Therapeutics: Research Funding; Juno Therapeutics: Membership on an entity's Board of Directors or advisory committees; Agios Pharm: Membership on an entity's Board of Directors or advisory committees; Oncotracker: Membership on an entity's Board of Directors or advisory committees; Dava Oncology: Membership on an entity's Board of Directors or advisory committees; Targeted 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; Behring: Membership on an entity's Board of Directors or advisory committees.

Abstract CD19-targeted chimeric antigen receptor T cell (CART19) therapy has been remarkably successful in treating a subset of patients with hematological malignancies. However, it is associated with significant toxicities, including cytokine release syndrome (CRS) and neurotoxicity (NT). Furthermore, the rate of durable responses after CART19 therapy is low, and most patients develop resistance to the therapy. One of the predominant mechanisms for CART cell resistance is intrinsic T cell dysfunction which leads to a suboptimal CART product. The Bruton's tyrosine kinase (BTK) inhibitor ibrutinib has been shown to favorably modulate CART phenotype and function through downregulation of inhibitory receptors and enhancement of CART cell efficacy in preclinical models and early clinical studies. However, ibrutinib is an irreversible receptor tyrosine kinase (RTK) inhibitor, and thus there are concerns that it inhibits CART cell proliferation and expansion. In contrast to ibrutinib and other BTK inhibitors, vecabrutinib has recently emerged as a potent, reversible, non-covalent BTK inhibitor that can block the activity of both wild type and C481 mutant BTK as well as interleukin-2-inducible T-cell kinase (ITK). We hypothesized that treatment with vecabrutinib improves CART19 antitumor efficacy through the reversible inhibition of BTK/ITK, independent of its antitumor effect. To test this hypothesis, we assessed whether vecabrutinib potentiates CART19 cytotoxicity against CD19 + tumor cells. Killing of the CD19 + mantle cell lymphoma cell line, JeKo-1, was significantly increased when CART19 were combined with vecabrutinib (Fig. 1A). Of note, vecabrutinib did not induce antitumor activity in this model as a single agent (Fig. 1A). In addition, vecabrutinib (10 µM) treatment of CART19 resulted in enhanced antigen-specific proliferation (Fig. 1B). Next, we aimed to study the direct impact of vecabrutinib on CART19 cytokine production. We measured the levels of multiple pro-inflammatory cytokines in the supernatant of CART19 co-cultured for 3 days with JeKo-1 cells and vecabrutinib. Vecabrutinib did not impair CART19 degranulation, as measured by flow cytometric assessment of CD107a expression (Fig. 1C). Cytokines known to play a crucial part in the development of CRS, such as IL-6, IL-10, and MIP-1β were significantly downregulated in cocultures with vecabrutinib (Fig. 1D-F). We then investigated whether the addition of vecabrutinib to CART19 caused a synergistic antitumor effect in vivo. We used our established JeKo-1 lymphoma xenograft models. Here NSG mice were engrafted with CD19 + luciferase + JeKo-1 cells. Mice were then imaged for engraftment and randomized to treatment with 1) untransduced control T cells, 2) CART19 with vehicle, or 3) CART19 with vecabrutinib 50 mg/kg BID administered via oral gavage over a period of 4 weeks. Vecabrutinib combination with CART19 treatment led to sustained antitumor activity (Fig.1G) and increased CART19 proliferation (Fig.1H). Encouragingly, mice treated with vecabrutinib better maintained their body weight following CART19 infusion, suggesting possibly dampened toxicity (Fig.1I). We also measured serum cytokine levels from patients on a phase 1 clinical trial (NCT03037645) testing vecabrutinib in B cell malignancies at baseline and four weeks after treatment. We found that vecabrutinib significantly reduces the levels of multiple pro-inflammatory cytokines linked to CART cell toxicity, including MIP-1β, IP-10, and TNF-a (Fig. 1J-L), further validating our preclinical findings. Finally, we interrogated the transcriptome of CART19 co-cultured with JeKo-1 with or without vecabrutinib. Total RNA sequencing of activated CART19 highlighted a significant enhanced expression of multiple genes involved in the PI3K/AKT and Th1 pathways compared to antigen stimulated CART19 alone (Fig.1M, N). These results could explain the enhanced proliferation and cytotoxicity induced by vecabrutinib. In summary, we demonstrate for the first time that using the reversible BTK inhibitor, vecabrutinib, is a potent and a novel strategy to favorably modulate CART19 function by increasing their efficacy and decreasing toxicity. Further studies are currently underway to compare the effect of reversible versus irreversible BTK/ITK inhibition on CART functions and to further validate the mechanisms responsible for the observed effects. Figure 1 Figure 1. Disclosures Sakemura: Humanigen: Patents & Royalties. Cox: Humanigen: Patents & Royalties. Fox: Sunesis Pharmaceuticals: Current Employment. Ding: 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; DTRM: Research Funding. Parikh: Pharmacyclics, MorphoSys, Janssen, AstraZeneca, TG Therapeutics, Bristol Myers Squibb, Merck, AbbVie, and Ascentage Pharma: Research Funding; Pharmacyclics, AstraZeneca, Genentech, Gilead, GlaxoSmithKline, Verastem Oncology, and AbbVie: Membership on an entity's Board of Directors or advisory committees. Kay: MEI Pharma: Research Funding; Sunesis: Research Funding; Rigel: Membership on an entity's Board of Directors or advisory committees; AstraZeneca: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; CytomX Therapeutics: Membership on an entity's Board of Directors or advisory committees; TG Therapeutics: Research Funding; Juno Therapeutics: 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; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Behring: Membership on an entity's Board of Directors or advisory committees; Genentech: Research Funding; Morpho-sys: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees, Research Funding; Targeted Oncology: Membership on an entity's Board of Directors or advisory committees; Tolero Pharmaceuticals: Research Funding; Dava Oncology: Membership on an entity's Board of Directors or advisory committees; Acerta Pharma: Research Funding; Agios Pharm: 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; Oncotracker: Membership on an entity's Board of Directors or advisory committees. Kenderian: Humanigen, Inc.: Consultancy, Honoraria, Research Funding.

Abstract Introduction: It has become increasingly apparent that chimeric antigen receptor T (CART) cell activation and differentiation level is an important determinant of CART cell fate and response to therapy. In this study, we aimed to 1) measure levels of activation-induced surface death receptors and ligands on CART cells; 2) investigate how CART cell activation could impact their fitness and clinical responses, and 3) identify cell-based targets to modulate CART cell activation, apoptosis, and cytotoxicity to improve anti-tumor activity. Methods: We performed flow cytometric studies on ex-vivo stimulated, clinically annotated CART products of patients with large B cell lymphoma from the pivotal ZUMA-1 clinical trial that led to FDA-approved Axicabtagene ciloleucel (Axi-Cel). We investigated possible correlations of a number of surface death receptors and ligands with T cell differentiation status and post-infusion CART cell expansion, utilizing samples from ZUMA-1 patients who achieved a complete response as a best outcome ('responders') vs patients who achieved stable or progressive disease('non-responders'). CART cell effector functions in vitro were measured, and CART apoptosis was assessed using Annexin V. For in vitro and in vivo functional studies, we used CART19 generated from healthy donors (HD CART19) as indicated in the specific experiment. CRISPR/Cas9 was employed during CART cell production to disrupt specific genes. A xenograft model of lymphoma was used to investigate the in vivo antitumor activity of CART19. Results: Following an ex vivo stimulation of Axi-Cel products with CD19 + target cells, we observed upregulation of death receptors and ligands in CART19 from non-responders, compared to responders. We also observed a possible association between such upregulated surface markers with CART cell differentiation as measured by CCR7 expression. In an extended in vitro co-culture assay, where HD CART19 cells were repeatedly stimulated through the CAR, we found that tumor necrosis factor α receptor 2 (TNFR2), unlike other death receptors and ligands, was persistently elevated, suggesting a possible role for TNFR2 in long-term antigen-dependent CART19 dysfunction (Figure 1A). We further found that HD CART19 upregulate TNFR2, but not TNFR1, upon CAR stimulation (Figure 1B). While non-specific TCR activation (CD3 stimulation) of HD CART19 cells protected them from activation-induced apoptosis, antigen-specific activation through the CAR resulted in significant initiation of apoptosis within 2 hours of stimulation (Figure 1C). Having identified a possible association between TNFR2 and CART19 dysfunction, we aimed to study the impact of TNFR2 knockout on HD CART19 functions. Using CRISPR/Cas9 during CART cell manufacturing, we generated TNFR2 k/o HD CART19 cells with a knockout efficiency of around 50%, where the expression levels of TNFR2 in activated CART19 cells were reduced, compared to control CART19 cells (with non-targeting gRNA CRISPR/Cas9, Figure 1D). TNFR2 k/o CART19 cells demonstrated reduced early activation surface markers compared to control CART19, as measured by CD25 and CD69 surface expression (Figure 1E), reduced apoptosis initiation as measured by the Annexin V assay (Figure 1F), and enhanced antigen-specific proliferation and cytotoxicity (Figure 1G). Finally, in an in vivo xenograft model of CD19 + lymphoma, TNFR2 k/o CART19 resulted in enhanced CART cell expansion and anti-tumor activity (Figure 1H). Conclusions: Our results indicate that TNFR2 plays a role in early activation and apoptosis initiation of CART19 following CAR stimulation with CD19 + target cells and present TNFR2 knockout as a strategy to enhance CART19 anti-tumor activity. Figure 1 Figure 1. Disclosures Cox: Humanigen: Patents & Royalties. Sakemura: Humanigen: Patents & Royalties. Ding: Merck: Membership on an entity's Board of Directors or advisory committees, Research Funding; DTRM: Research Funding; Octapharma: Membership on an entity's Board of Directors or advisory committees. Parikh: Pharmacyclics, MorphoSys, Janssen, AstraZeneca, TG Therapeutics, Bristol Myers Squibb, Merck, AbbVie, and Ascentage Pharma: Research Funding; Pharmacyclics, AstraZeneca, Genentech, Gilead, GlaxoSmithKline, Verastem Oncology, and AbbVie: Membership on an entity's Board of Directors or advisory committees. Kay: Juno Therapeutics: 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; MEI Pharma: Research Funding; Celgene: 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; Agios Pharm: Membership on an entity's Board of Directors or advisory committees; Targeted Oncology: Membership on an entity's Board of Directors or advisory committees; AstraZeneca: Membership on an entity's Board of Directors or advisory committees; Acerta Pharma: Research Funding; Genentech: Research Funding; Behring: Membership on an entity's Board of Directors or advisory committees; CytomX Therapeutics: Membership on an entity's Board of Directors or advisory committees; Sunesis: Research Funding; TG Therapeutics: Research Funding; Tolero Pharmaceuticals: Research Funding; Abbvie: 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; Morpho-sys: Membership on an entity's Board of Directors or advisory committees; Janssen: 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. Scholler: Kite: Current Employment. Bot: Kite, a Gilead Company: Current Employment; Gilead Sciences: Consultancy, Current equity holder in publicly-traded company, Other: Travel support. Mattie: Kite: Current Employment. Kim: Gilead Sciences: Current equity holder in publicly-traded company; Kite, a Gilead Company: Current Employment. Filosto: Kite, a Gilead Company: Current Employment; Tusk Therapeutics: Patents & Royalties: or other intellecular property; Gilead Sciences: Other: stock or other ownership . Kenderian: Humanigen, Inc.: Consultancy, Honoraria, Research Funding.

Abstract Anti-CD19 chimeric antigen receptor T (CART19) cell therapy has resulted in unprecedented outcomes in patients with relapsed/refractory B-cell malignancies, which led to the FDA approval for several indications. However, CART19 cell therapy is limited by the development of severe life-threatening toxicities, as well as by the limited rates of durable response. It has become apparent that myeloid cells contribute to the development of both CART cell toxicity and also to the inhibitory tumor microenvironment. We and others have identified that granulocyte-monocyte-colony-stimulating factor (GM-CSF) depletion results in decreased myeloid activation, reduced toxicities, and enhancement of CART19 cell therapy efficacy in pre-clinical models. Furthermore, we observed that GM-CSF knockout (GM-CSF k/o) in CART19 cells resulted in the improvement of their functions (in vitro and in vivo). These findings suggest that there is also a direct effect of GM-CSF on CART19 cells, which is independent of the GM-CSF impact on myeloid cell activation. To further evaluate this, we first examined GM-CSF receptor alpha (GM-CSFRα) expression by flow cytometry on resting and activated CART19 cells (using FMC63-41BBζ). When CART19 cells were stimulated with either anti-CD3/CD28 beads or lethally irradiated (120 Gy) CD19 + Nalm6 cells (B cell acute lymphoblastic leukemia cancer cell line), GM-CSFRα expression was upregulated upon both T cell receptor (TCR) (data not shown) and CAR stimulation (Figure 1A). Having demonstrated that GM-CSFRα is significantly upregulated on stimulated CART19 cells, we aimed to determine the impact of GM-CSF neutralization (clinical-grade anti-GM-CSF antibody, lenzilumab, 10 µg/mL) versus GM-CSFRα blockade (research-grade antibody, 10 µg/mL) on CART19 cell function and CART cell-monocyte interactions. An IgG isotype antibody was used as a control antibody. Neither the GM-CSF neutralizing antibody, nor GM-CSFRα blocking antibody, had any impact on CART19 cell antigen-specific killing against the CD19 + JeKo-1 cells (mantle cell lymphoma cancer cell line), in the presence or absence of CD14 + monocytes (ratio 1:1:1) isolated by magnetic beads from healthy donors (Figures 1B-C). Next, we compared the effects of GM-CSF neutralization versus GM-CSFRα blockade on CART19 cell antigen-specific proliferation. Here, CART19 cells were co-cultured with lethally irradiated CD19 + cell line JeKo-1 at 1:1 ratio in the presence of 10 µg/mL of the GM-CSF neutralizing antibody, increasing doses of the GM-CSFRα blocking antibody (10-100 µg/mL), or an IgG control. The absolute number of CART cells was measured by flow cytometry on day 5. GM-CSF neutralization did not affect CART19 cell proliferation, but GM-CSFRα blocking antibody significantly inhibited CART19 cell proliferation in a dose-dependent manner. Then, we assessed the effects of GM-CSF neutralizing antibody (20 µg/mL) versus GM-CSFRα blocking antibody (20 µg/mL) on CART19 cell antigen-specific proliferation in the presence of healthy donor monocytes (ratio 1:1:0.5) on day 3. Flow cytometric analysis revealed that GM-CSF neutralization, but not GM-CSFRα blockade, mitigated monocyte-suppression of CART19 antigen-specific proliferation (Figure 1E). In summary, our findings indicate significant differences on CART cell functions and CART cell-monocyte interactions when a specific cytokine, GM-CSF, is neutralized compared to blocking its receptor. Further mechanistic studies are ongoing to assess the functions of GM-CSFRα k/o and GM-CSF k/o CART cells. Figure 1 Figure 1. Disclosures Sakemura: Humanigen: Patents & Royalties. Parikh: Pharmacyclics, MorphoSys, Janssen, AstraZeneca, TG Therapeutics, Bristol Myers Squibb, Merck, AbbVie, and Ascentage Pharma: Research Funding; Pharmacyclics, AstraZeneca, Genentech, Gilead, GlaxoSmithKline, Verastem Oncology, and AbbVie: Membership on an entity's Board of Directors or advisory committees. Kay: Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; AstraZeneca: Membership on an entity's Board of Directors or advisory committees; Tolero Pharmaceuticals: Research Funding; CytomX Therapeutics: Membership on an entity's Board of Directors or advisory committees; MEI Pharma: Research Funding; Dava Oncology: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees, Research Funding; Morpho-sys: Membership on an entity's Board of Directors or advisory committees; TG Therapeutics: Research Funding; Acerta Pharma: Research Funding; Genentech: Research Funding; Rigel: Membership on an entity's Board of Directors or advisory committees; Behring: 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; Targeted Oncology: Membership on an entity's Board of Directors or advisory committees; Juno Therapeutics: 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; Janssen: Membership on an entity's Board of Directors or advisory committees; Oncotracker: Membership on an entity's Board of Directors or advisory committees; Agios Pharm: Membership on an entity's Board of Directors or advisory committees. Durrant: Humanigen Inc.: Current Employment. Ahmed: Humanigen Inc.: Current Employment, Current equity holder in publicly-traded company. Chappell: Humanigen Inc.: Current Employment, Current equity holder in publicly-traded company, Divested equity in a private or publicly-traded company in the past 24 months. Cox: Humanigen: Patents & Royalties. Kenderian: Humanigen, Inc.: Consultancy, Honoraria, Research Funding.

Abstract The management of chronic lymphocytic leukemia (CLL) has undergone unprecedented changes over the last decade. Modern targeted therapies are incorporated into clinical practice. Unfortunately, patients have begun to develop resistance or intolerance to multiple classes. Symptomatic patients previously treated with a BTK inhibitor (BTKi) and venetoclax represent a new and rapidly growing unmet need in CLL. Here, we define unmet needs in a modern treatment context. We also critically review the literature for PI3K inhibitors and chemoimmunotherapy and lack of data to support their utility following BTKis and venetoclax. Finally, we suggest opportunities to ensure the continued innovation for patients with CLL.

Abstract Background: Vaccinations have been hypothesized to play a role in lymphoma etiology, but there are few studies, mixed results, and limited data on lymphoma subtypes. Herein, we investigate the association of vaccinations with risk of major lymphoma subtypes. Methods: We studied 2,461 lymphoma cases and 2,253 controls enrolled from 2002 to 2014. Participants self-reported history of vaccinations against hepatitis A, hepatitis B, yellow fever, and influenza. Polytomous logistic regression was used to estimate OR and 95% confidence intervals (CI), adjusting for potential confounders. Results: After multivariable adjustment, vaccination against influenza was inversely associated with lymphoma (OR = 0.82; 95% CI, 0.66–1.02), which was stronger for last vaccination 1+ years before enrollment (OR = 0.71; 95% CI, 0.56–0.91) and for >5 influenza vaccinations (OR = 0.56; 95% CI, 0.46–0.68). Ever vaccination against hepatitis A (OR = 0.81; 95% CI, 0.66–1.00) but not hepatitis B (OR = 0.97; 95% CI, 0.81–1.18) was associated with lymphoma risk, although more recent vaccinations were inversely associated with lymphoma risk for both hepatitis A (<6 years before enrollment, OR = 0.56; 95% CI, 0.40–0.77) and hepatitis B (<9 years before enrollment, OR = 0.72; 95% CI, 0.55–0.93). Ever vaccination against yellow fever was inversely associated with risk (OR = 0.73; 95% CI, 0.55–0.96), and this did not vary by time since last vaccination. Although there was no overall statistical evidence for heterogeneity of vaccination history by lymphoma subtype, the only statistically significant inverse associations were observed for influenza and yellow fever vaccinations with diffuse large B-cell and follicular lymphoma. Conclusions: Selected vaccinations were inversely associated with lymphoma risk, with time since last vaccination relevant for some of these vaccines. Impact: Vaccinations against hepatitis A, hepatitis B, yellow fever, and influenza are unlikely to increase lymphoma risk.

AbstractMonoclonal B‐cell lymphocytosis (MBL) and chronic lymphocytic leukemia (CLL) are clonal B‐cell disorders associated with an increased risk of infections and impaired vaccination responses. We investigated the immunogenicity of recombinant zoster vaccine (RZV) in these patients. Individuals with MBL/untreated CLL and Bruton tyrosine kinase inhibitor (BTKi)‐treated CLL patients were given two doses of RZV separated by 2 months. Responses assessed at 3 and 12 months from the first dose of RZV by an anti‐glycoprotein E ELISA antibody assay and by dual‐color Interferon‐γ and Interleukin‐2FLUOROSPOT assays were compared to historic controls matched by age and sex. About 62 patients (37 MBL/untreated CLL and 25 BTKi‐treated CLL) were enrolled with a median age of 68 years at vaccination. An antibody response at 3 months was seen in 45% of participants, which was significantly lower compared to historic controls (63%, p = .03). The antibody response did not significantly differ between MBL/untreated CLL and BTKi‐treated CLL (51% vs. 36%, respectively, p = .23). The CD4+ T‐cell response to vaccination was significantly lower in study participants compared to controls (54% vs. 96%, p < .001), mainly due to lower responses among BTKi‐treated patients compared to untreated MBL/CLL (32% vs. 73%, p = .008). Overall, only 29% of participants achieved combined antibody and cellular responses to RZV. Among participants with response assessment at 12 months (n = 47), 24% had antibody titers below the response threshold. Hypogammaglobulinemia and BTKi therapy were associated with reduced T‐cell responses in a univariate analysis. Strategies to improve vaccine response to RZV among MBL/CLL patients are needed.