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•Mosunetuzumab is active as a single agent and yields CRs in 24% of heavily pretreated patients with R/R DLBCL.•Step-up dosing mitigated CRS events with mosunetuzumab, which has a manageable tolerability profile in R/R DLBCL.

•Molecular profiling of MZL may assist in the rational use of BTK inhibitor therapy.•BTKand PLCG2mutations confer acquired resistance of MZL to BTK inhibition.

Preclinical data demonstrated that combining an anti–programmed cell death 1 (PD-1) inhibitor with a cyclin-dependent kinase 9 (CDK9) inhibitor provided enhanced antitumor activity with no significant toxicities, suggesting this combination may be a potential therapeutic option. The multicohort, phase 1 KEYNOTE-155 study evaluated the safety and antitumor activity of the PD-1 inhibitor pembrolizumab plus the CDK9 inhibitor dinaciclib in patients with relapsed or refractory (rr) chronic lymphocytic leukemia (CLL), diffuse large B-cell lymphoma (DLBCL) and multiple myeloma (MM). Patients enrolled were ≥18 years of age with a confirmed diagnosis of CLL, DLBCL, or MM. The study included 2 phases: a dose-evaluation phase to determine dose-limiting toxicities and a signal-detection phase. Patients received pembrolizumab 200 mg every 3 weeks plus dinaciclib 7 mg/m2 on day 1 and 10 mg/m2 on day 8 of cycle 1 and 14 mg/m2 on days 1 and 8 of cycles 2 and later. Primary endpoint was safety, and a key secondary endpoint was objective response rate (ORR). Seventy-two patients were enrolled and received ≥1 dose of study treatment (CLL, n = 17; DLBCL, n = 38; MM, n = 17). Pembrolizumab plus dinaciclib was generally well tolerated and produced no unexpected toxicities. The ORRs were 29.4% (5/17, rrCLL), 21.1% (8/38, rrDLBCL), and 0% (0/17, rrMM), respectively. At data cutoff, all 72 patients had discontinued treatment, 38 (52.8%) because of progressive disease. These findings demonstrate activity with combination pembrolizumab plus dinaciclib and suggest that a careful and comprehensive approach to explore anti–PD-1 and CDK9 inhibitor combinations is warranted. This trial was registered at www.clinicaltrials.gov as NCT02684617.

Preclinical data demonstrated that combining an anti–programmed cell death 1 (PD-1) inhibitor with a cyclin-dependent kinase 9 (CDK9) inhibitor provided enhanced antitumor activity with no significant toxicities, suggesting this combination may be a potential therapeutic option. The multicohort, phase 1 KEYNOTE-155 study evaluated the safety and antitumor activity of the PD-1 inhibitor pembrolizumab plus the CDK9 inhibitor dinaciclib in patients with relapsed or refractory (rr) chronic lymphocytic leukemia (CLL), diffuse large B-cell lymphoma (DLBCL) and multiple myeloma (MM). Patients enrolled were ≥18 years of age with a confirmed diagnosis of CLL, DLBCL, or MM. The study included 2 phases: a dose-evaluation phase to determine dose-limiting toxicities and a signal-detection phase. Patients received pembrolizumab 200 mg every 3 weeks plus dinaciclib 7 mg/m2on day 1 and 10 mg/m2on day 8 of cycle 1 and 14 mg/m2on days 1 and 8 of cycles 2 and later. Primary endpoint was safety, and a key secondary endpoint was objective response rate (ORR). Seventy-two patients were enrolled and received ≥1 dose of study treatment (CLL, n = 17; DLBCL, n = 38; MM, n = 17). Pembrolizumab plus dinaciclib was generally well tolerated and produced no unexpected toxicities. The ORRs were 29.4% (5/17, rrCLL), 21.1% (8/38, rrDLBCL), and 0% (0/17, rrMM), respectively. At data cutoff, all 72 patients had discontinued treatment, 38 (52.8%) because of progressive disease. These findings demonstrate activity with combination pembrolizumab plus dinaciclib and suggest that a careful and comprehensive approach to explore anti–PD-1 and CDK9 inhibitor combinations is warranted. This trial was registered at www.clinicaltrials.govas NCT02684617.

Peripheral T-cell lymphoma (PTCL) is a rare, heterogenous malignancy with dismal outcomes at relapse. Hypomethylating agents (HMA) have an emerging role in PTCL, supported by shared mutations with myelodysplasia (MDS). Response rates to azacitidine in PTCL of follicular helper cell origin are promising. Guadecitabine is a decitabine analogue with efficacy in MDS. In this phase II, single-arm trial, PTCL patients received guadecitabine on days 1–5 of 28-day cycles. Primary end points were overall response rate (ORR) and safety. Translational sub-studies included cell free plasma DNA sequencing and functional genomic screening using an epigenetically-targeted CRISPR/Cas9 library to identify response predictors. Among 20 predominantly relapsed/refractory patients, the ORR was 40% (10% complete responses). Most frequent grade 3-4 adverse events were neutropenia and thrombocytopenia. At 10 months median follow-up, median progression free survival (PFS) and overall survival (OS) were 2.9 and 10.4 months respectively. RHOAG17Vmutations associated with improved PFS (median 5.47 vs. 1.35 months; Wilcoxon p= 0.02, Log-Rank p= 0.06). 4/7 patients with TP53variants responded. Deletion of the histone methyltransferase SETD2sensitised to HMA but TET2deletion did not. Guadecitabine conveyed an acceptable ORR and toxicity profile; decitabine analogues may provide a backbone for future combinatorial regimens co-targeting histone methyltransferases.

BH3 mimetics like venetoclax target prosurvival Bcl-2 family proteins and are important therapeutics in the treatment of hematological malignancies. We demonstrate that endogenous Bfl-1 expression can render preclinical lymphoma tumor models insensitive to Mcl-1 and Bcl-2 inhibitors. However, suppression of Bfl-1 alone was insufficient to fully induce apoptosis in Bfl-1–expressing lymphomas, highlighting the need for targeting additional prosurvival proteins in this context. Importantly, we demonstrated that cyclin-dependent kinase 9 (CDK9) inhibitors rapidly downregulate both Bfl-1 and Mcl-1, inducing apoptosis in BH3-mimetic–resistant lymphoma cell lines in vitro and driving in vivo tumor regressions in diffuse large B-cell lymphoma patient-derived xenograft models expressing Bfl-1. These data underscore the need to clinically develop CDK9 inhibitors, like AZD4573, for the treatment of lymphomas using Bfl-1 as a selection biomarker.

BH3 mimetics like venetoclax target prosurvival Bcl-2 family proteins and are important therapeutics in the treatment of hematological malignancies. We demonstrate that endogenous Bfl-1 expression can render preclinical lymphoma tumor models insensitive to Mcl-1 and Bcl-2 inhibitors. However, suppression of Bfl-1 alone was insufficient to fully induce apoptosis in Bfl-1–expressing lymphomas, highlighting the need for targeting additional prosurvival proteins in this context. Importantly, we demonstrated that cyclin-dependent kinase 9 (CDK9) inhibitors rapidly downregulate both Bfl-1 and Mcl-1, inducing apoptosis in BH3-mimetic–resistant lymphoma cell lines in vitro and driving in vivo tumor regressions in diffuse large B-cell lymphoma patient-derived xenograft models expressing Bfl-1. These data underscore the need to clinically develop CDK9 inhibitors, like AZD4573, for the treatment of lymphomas using Bfl-1 as a selection biomarker.

MCL-1 is one of the most frequently amplified genes in cancer, facilitating tumor initiation and maintenance and enabling resistance to anti-tumorigenic agents including the BCL-2 selective inhibitor venetoclax. The expression of MCL-1 is maintained via P-TEFb-mediated transcription, where the kinase CDK9 is a critical component. Consequently, we developed a series of potent small-molecule inhibitors of CDK9, exemplified by the orally active A-1592668, with CDK selectivity profiles that are distinct from related molecules that have been extensively studied clinically. Short-term treatment with A-1592668 rapidly downregulates RNA pol-II (Ser 2) phosphorylation resulting in the loss of MCL-1 protein and apoptosis in MCL-1-dependent hematologic tumor cell lines. This cell death could be attenuated by either inhibiting caspases or overexpressing BCL-2 protein. Synergistic cell killing was also observed between A-1592668 or the related analog A-1467729, and venetoclax in a number of hematologic cell lines and primary NHL patient samples. Importantly, the CDK9 inhibitor plus venetoclax combination was well tolerated in vivo and demonstrated efficacy superior to either agent alone in mouse models of lymphoma and AML. These data indicate that CDK9 inhibitors could be highly efficacious in tumors that depend on MCL-1 for survival or when used in combination with venetoclax in malignancies dependent on MCL-1 and BCL-2.

Background:Lymphocyte-activation gene 3 (LAG-3) is involved in the regulation of T-cell function and is commonly coexpressed with PD-1 on anergic T cells. Favezelimab (MK-4280), a humanized IgG4 anti-LAG-3 monoclonal antibody, plus pembrolizumab (anti-PD-1) is being investigated in the multicohort phase 1/2 MK-4280-003 efficacy and safety study (NCT03598608) in patients with relapsed or refractory (R/R) hematologic malignancies. Prior analyses of the combination demonstrated antitumor activity and manageable safety in patients with anti-PD-1-naive R/R classical Hodgkin lymphoma (cHL; cohort 1; ORR, 73%; CR, 30%) (Johnson NA et al. Blood. 2022;140(suppl 1):6540-2) and anti-PD-1-refractory cHL (cohort 2; ORR, 29%; CR, 9%) (Timmerman J et al. Blood. 2022;140(suppl 1):768-70). We present results from analysis of patients with R/R DLBCL enrolled in cohort 3.

Background and Significance:PRT2527 is an investigational, potent, and highly selective cyclin-dependent kinase 9 inhibitor that is being developed for select relapsed or refractory (R/R) hematologic malignancies. CDK9, a key regulator of transcription elongation, has been studied as a potential target for therapy in transcriptionally addicted cancers that are dependent on oncogenic drivers with short half-lives. Although most of these drivers do not respond to direct inhibition, studies suggest that a subset of drivers, eg MYC, MYB, and MCL-1, may be targeted indirectly via CDK9 inhibition. Several nonselective CDK9 inhibitors have shown clinical activity in multiple tumor types, however, tolerability was poor (Mandal, et al. Cancers (Basel). 2021). PRT2527 has demonstrated high specificity and promising antitumor activity in preclinical studies, and a favorable tolerability profile in preliminary data from a Phase 1 study (NCT05159518) in adults with advanced solid tumors. These support further development of PRT2527 in hematologic malignancies as monotherapy and in combination with targeted agents. Combination of CDK9 inhibition and Bruton tyrosine kinase (BTK) inhibition may drive a durable response by enhancing apoptotic priming and shifting dependency toward CDK9 targets MCL1 and BFL1. Zanubrutinib (BGB-3111) is a highly selective, potent, irreversible BTK inhibitor that upregulates the proapoptotic signaling molecule BCL2 modifying factor, an endogenous inhibitor of BCL2, BCLXL, and BCLW (Kong, et al. ChemMedChem. 2018). PRT2527 as monotherapy or in combination with zanubrutinib may be an effective treatment option for select R/R hematologic malignancies.

Introduction:Programmed cell death protein 1 (PD-1) inhibitors such as pembrolizumab play an important role in the treatment of patients with relapsed or refractory (R/R) classical Hodgkin lymphoma (cHL), but treatment failure remains a significant challenge. Lymphocyte-activation gene 3 (LAG-3) is an immune checkpoint receptor that downregulates T-cell activity and plays a role in regulating T-cell function. Dual blockade of PD-1 and LAG-3 demonstrated antitumor activity in patients with advanced melanoma in the RELATIVITY-047 trial, which led to FDA approval in this setting. Favezelimab is a humanized IgG4 monoclonal antibody directed against LAG-3 that is being investigated in combination with pembrolizumab in patients with R/R hematologic malignancies in a multicohort phase 1/2 study (NCT03598608). Prior analyses of this study demonstrated that pembrolizumab 200 mg plus favezelimab 800 mg every 3 weeks (Q3W) exhibited sustained antitumor activity and acceptable safety in the cohort of patients with anti-PD-1-naive R/R cHL (cohort 1). We present updated results from this cohort.

Background: Programmed cell death protein 1 (PD-1) inhibitors are a standard of care for relapsed or refractory (R/R) classical Hodgkin lymphoma (cHL), but better treatment options are needed for patients with anti-PD-1-refractory disease. Lymphocyte-activation gene 3 (LAG-3) is an immune checkpoint receptor with a role in regulating T-cell function. Dual blockade of PD-1 and LAG-3 has demonstrated antitumor activity in patients with advanced melanoma. Combination therapy with favezelimab (anti-LAG-3) and pembrolizumab (anti-PD-1) is currently being investigated in a phase 1/2 study (NCT03598608) in patients with R/R hematologic malignancies. Prior analyses showed that the combination had antitumor activity and manageable safety in patients with heavily pretreated anti-PD-1-refractory cHL (cohort 2). Updated results for this cohort are presented.

Background:

Sarit Assouline and Won Seog Kim contributed equally.

The identification of oncogenic ‘driver’ mutations and activated survival pathways in selected aggressive B-cell malignancies directs the development of novel adjunctive therapies using targeted small molecule inhibitors. With a focus on diffuse large B-cell lymphoma ‘not otherwise specified’, Hodgkin lymphoma and childhood B-cell precursor acute lymphoblastic leukemia, this review will provide an up-to-date account of the current literature on the development of new molecularly targeted treatment modalities for aggressive B-cell malignancies.

Introduction

Introduction:

Aim:

Lewis: AstraZeneca: Consultancy, Honoraria; Janssen: Honoraria, Patents & Royalties: Conference attendance; Novartis: Patents & Royalties: Conference attendance; Roche: Consultancy, Honoraria. Gunjur: Myers Squibb: Honoraria. Ku: Roche: Consultancy; Antegene: Consultancy; Genor Biopharma: Consultancy. Wight: Jannsen: Honoraria, Other: Travel subsidies; Abbvie: Honoraria, Other: Travel subsidies. Shortt: Amgen: Research Funding; Astex: Research Funding; BMS: Research Funding; Novartis: Membership on an entity's Board of Directors or advisory committees; Astellas: Membership on an entity's Board of Directors or advisory committees. Talaulikar: Roche: Honoraria, Research Funding; Jansenn: Honoraria, Research Funding; Amgen: Honoraria, Research Funding; Takeda: Honoraria, Research Funding; EUSA Pharma: Honoraria, Research Funding. Hawkes: Gilead: Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees, Other: Travel and accommodation expenses, Research Funding, Speakers Bureau; Regeneron: Speakers Bureau; Novartis: Membership on an entity's Board of Directors or advisory committees; Merck Sharpe Dohme: Membership on an entity's Board of Directors or advisory committees; Janssen: Speakers Bureau; Astra Zeneca: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Merck KgA: Research Funding; Bristol Myers Squib/Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Specialised Therapeutics: Consultancy; Antigene: Membership on an entity's Board of Directors or advisory committees. Cheah: MSD: Consultancy, Honoraria, Other: advisory, Research Funding; Janssen: Consultancy, Honoraria, Other: advisory; TG Therapeutics: Consultancy, Honoraria, Other: advisory; Roche: Consultancy, Honoraria, Other: advisory and travel expenses, Research Funding; Loxo/Lilly: Consultancy, Honoraria, Other: advisory; AstraZeneca: Consultancy, Honoraria, Other: advisory; Celgene: Research Funding; AbbVie: Research Funding; Beigene: Consultancy, Honoraria, Other: advisory; Ascentage pharma: Consultancy, Honoraria, Other: advisory; Gilead: Consultancy, Honoraria, Other: advisory. Opat: Merck: Honoraria, Membership on an entity's Board of Directors or advisory committees; Abbvie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Astra Zeneca: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; BeiGene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Pharmacyclics: Research Funding; Sandoz: Research Funding; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; CSL Behring: Honoraria, Membership on an entity's Board of Directors or advisory committees; Monash Health: Current Employment. Gregory: Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel fees, Speakers Bureau; Janssen: Consultancy; Novartis: Consultancy.

Greenwood: Amgen: Membership on an entity's Board of Directors or advisory committees, Research Funding; Pfizer: Membership on an entity's Board of Directors or advisory committees; Servier: Membership on an entity's Board of Directors or advisory committees, Research Funding; Jazz Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees. Gregory: Janssen: Consultancy; Novartis: Consultancy; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel fees, Speakers Bureau. Hamad: Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau.

Budde: Mustang Bio, Inc: Research Funding; Roche: Consultancy; BeiGene: Consultancy; Novartis: Consultancy; AstraZeneca: Research Funding; IGM Biosciences: Research Funding; Merck, Inc: Research Funding; Amgen: Research Funding; Gilead: Consultancy. Gopal: Agios: Research Funding; MorphoSys: Honoraria; Bristol Meyers Squibb: Research Funding; Incyte: Honoraria; Acrotech: Consultancy, Honoraria; Servier: Consultancy, Honoraria; IGM Biosciences: Research Funding; Nurix Inc: Consultancy, Honoraria; Beigene: Consultancy, Honoraria; Astra-Zeneca: Research Funding; Takeda: Research Funding; Teva: Research Funding; ADC Therapeutics: Consultancy, Honoraria; Kite: Consultancy, Honoraria; Cellectar: Consultancy, Honoraria; Genetech: Consultancy, Honoraria, Research Funding; Gilead: Consultancy, Honoraria, Research Funding; I-Mab bio: Consultancy, Honoraria, Research Funding; Epizyme: Consultancy, Honoraria; SeaGen: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Karyopharm: Consultancy, Honoraria; Merck: Consultancy, Honoraria, Research Funding. Kim: Dong-A Pharmaceutical: Research Funding; Eisai: Research Funding; Celltrion: Research Funding; Johnson & Johnson: Research Funding; Kyowa Kirin: Research Funding; Roche: Research Funding; Sanofi: Research Funding; IGM Biosciences: Research Funding. Flinn: Novartis: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Seagen: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Incyte: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Pharmacyclics LLC, an AbbVie Company: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Forma Therapeutics: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Curis: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Forty Seven: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Infinity Pharmaceuticals: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; MorphoSys: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Constellation Pharmaceuticals: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Yingli Pharmaceuticals: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Verastem: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Calithera Biosciences: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; TG Therapeutics: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Celgene: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Takeda: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Juno Therapeutics: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Kite, a Gilead Company: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; IGM Biosciences: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Janssen: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Roche: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; AbbVie: Consultancy, Other: All Consultancy and Research Funding payments made to Sarah Cannon Research Institute, Research Funding; Gilead Sciences: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Trillium Therapeutics: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Acerta Pharma: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Karyopharm Therapeutics: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Loxo: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Merck: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Rhizen Pharmaceuticals: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Teva: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Agios: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Unum Therapeutics: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Nurix Therapeutics: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Pfizer: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Great Point Partners: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Portola Pharmaceuticals: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; ArQule: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Iksuda Therapeutics: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Genentech: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; BeiGene: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; AstraZeneca: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Triphase Research & Development Corp.: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Century Therapeutics: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Hutchison MediPharma: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Vincerx Pharma: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Sarah Cannon Research Institute: Current Employment; Servier Pharmaceuticals: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Yingli Pharmaceuticals: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Seagen: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Servier Pharmaceuticals: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Unum Therapeutics: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute, Research Funding; Johnson & Johnson: Current holder of individual stocks in a privately-held company; Seattle Genetics: Research Funding. Cheah: Ascentage Pharma: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; AstraZeneca: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; BMS: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses, Research Funding; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Gilead: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Lilly: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; TG therapeutics: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; MSD: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Beigene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Abbvie: Research Funding. Nastoupil: Bayer: Honoraria; Denovo Pharma: Other: DSMC; Novartis: Honoraria, Research Funding; Genentech: Honoraria, Research Funding; Pfizer: Honoraria, Research Funding; TG Therapeutics: Honoraria, Research Funding; Takeda: Honoraria, Other: DSMC, Research Funding; IGM Biosciences: Research Funding; Caribou Biosciences: Research Funding; Gilead/Kite: Honoraria, Research Funding; Bristol Myers Squibb/Celgene: Honoraria, Research Funding; Epizyme: Honoraria, Research Funding; ADC Therapeutics: Honoraria; Janssen: Honoraria, Research Funding; MorphoSys: Honoraria. Matasar: Daiichi Sankyo: Consultancy; TG Therapeutics: Consultancy, Honoraria; Merck Sharp & Dohme: Current holder of individual stocks in a privately-held company; Juno Therapeutics: Consultancy; Rocket Medical: Consultancy, Research Funding; Genentech, Inc.: Consultancy, Honoraria, Research Funding; Teva: Consultancy; F. Hoffmann-La Roche Ltd: Consultancy, Honoraria, Research Funding; Memorial Sloan Kettering Cancer Center: Current Employment; Bayer: Consultancy, Honoraria, Research Funding; GlaxoSmithKline: Honoraria, Research Funding; Merck: Consultancy; IGM Biosciences: Research Funding; Pharmacyclics: Honoraria, Research Funding; ImmunoVaccine Technologies: Consultancy, Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Seattle Genetics: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria. Diefenbach: Janssen: Consultancy, Honoraria, Research Funding; Morphosys: Consultancy, Honoraria, Research Funding; Merck Sharp & Dohme: Consultancy, Honoraria, Research Funding; Gilead: Current equity holder in publicly-traded company; Trillium: Research Funding; IGM Biosciences: Research Funding; Celgene: Research Funding; AbbVie: Research Funding; Perlmutter Cancer Center at NYU Langone Health: Current Employment; Incyte: Research Funding; MEI: Consultancy, Research Funding; Genentech, Inc./ F. Hoffmann-La Roche Ltd: Consultancy, Honoraria, Research Funding; Seattle Genetics: Consultancy, Honoraria, Research Funding; Bristol-Myers Squibb: Consultancy, Honoraria, Research Funding; IMab: Research Funding. Gregory: Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel fees, Speakers Bureau; Janssen: Consultancy; Novartis: Consultancy. Qazi: IGM Biosciences: Current Employment. Pang: IGM Biosciences: Consultancy. Leabman: IGM Biosciences: Current Employment. Hernandez: IGM Biosciences: Current Employment. Sison: IGM Biosciences: Current Employment. Keyt: IGM Biosciences: Current Employment. Chen: IGM Biosciences: Ended employment in the past 24 months. Armand: Enterome: Consultancy; C4: Consultancy; GenMab: Consultancy; Infinity: Consultancy; Otsuka: Research Funding; Regeneron: Consultancy; Pfizer: Consultancy; Morphosys: Consultancy; Daiichi Sankyo: Consultancy; Epizyme: Consultancy; Affimed: Consultancy, Research Funding; Adaptive: Consultancy, Research Funding; AstraZeneca: Consultancy; Genentech: Consultancy, Research Funding; Roche: Research Funding; Tensha: Research Funding; IGM: Research Funding; Kite: Research Funding; ADC Therapeutics: Consultancy; BMS: Consultancy, Honoraria, Research Funding; Sigma Tau: Research Funding; Merck: Consultancy, Honoraria, Research Funding; Celgene: Consultancy; Miltenyi: Consultancy; Tessa Therapeutics: Consultancy.

Lewis: AstraZeneca: Consultancy, Honoraria; Novartis: Patents & Royalties: Conference attendance; Janssen: Honoraria, Patents & Royalties: Conference attendance; Roche: Consultancy, Honoraria. Villa: Janssen: Honoraria; Gilead: Honoraria; AstraZeneca: Honoraria; AbbVie: Honoraria; Seattle Genetics: Honoraria; Celgene: Honoraria; Lundbeck: Honoraria; Roche: Honoraria; NanoString Technologies: Honoraria. Bobillo: F. Hoffmann-La Roche Ltd: Consultancy, Speakers Bureau; Gilead: Speakers Bureau. Ekstroem Smedby: Takeda: Consultancy; Janssen Cilag: Research Funding. Savage: Merck: Consultancy, Honoraria, Other: Institutional clinical trial funding; BMS: Consultancy, Honoraria, Other: Institutional clinical trial funding; AbbVie: Consultancy, Honoraria; Roche: Research Funding; Takeda: Other: Institutional clinical trial funding; Servier: Consultancy, Honoraria; Seattle Genetics: Consultancy, Honoraria; Astra-Zeneca: Consultancy, Honoraria; Beigene: Other: Institutional clinical trial funding; Genentech: Research Funding. Eyre: Beigene: Honoraria, Research Funding; Incyte: Consultancy; Secura Bio: Consultancy, Honoraria; Janssen: Honoraria; Gilead/KITE: Honoraria, Other: Travel support for conferences, Research Funding, Speakers Bureau; Loxo Oncology: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Abbvie: Consultancy, Honoraria, Other: Travel to conferences; AstraZeneca: Honoraria, Research Funding; Roche: Consultancy, Honoraria. Cwynarski: Incyte: Consultancy, Speakers Bureau; Gilead: Consultancy, Speakers Bureau; Atara: Consultancy; Celgene: Consultancy; Takeda: Consultancy, Other: travel to scientific conferences, Speakers Bureau; Kite, a Gilead Company: Consultancy, Other: travel to scientific conferences, Speakers Bureau; Janssen: Consultancy, Other: travel to scientific conferences; Roche: Consultancy, Other: travel to scientific conferences, Speakers Bureau; BMS/Celgene: Other: travel to scientific conferences. Stewart: Teva: Honoraria; Sandoz: Honoraria; Amgen: Honoraria; AstraZeneca: Honoraria; Novartis: Honoraria; Celgene: Honoraria; Gilead: Honoraria; Abbvie: Honoraria; Janssen: Honoraria; Roche: Honoraria. Bishton: Gilead: Honoraria, Other: Travel grants; AbbVie: Honoraria, Other: Travel grants; Celgene/BMS: Honoraria, Other: travel grants; Celltrion: Honoraria, Other: Travel grants; Takeda.: Honoraria, Other: Travel grants . Fox: F. Hoffmann-La Roche Ltd: Consultancy, Membership on an entity's Board of Directors or advisory committees. Joffe: Epizyme: Consultancy; AstraZeneca: Consultancy. Eloranta: Janssen Pharmaceutical NV: Other: NV. Sehn: Genmab: Consultancy; Novartis: Consultancy; Debiopharm: Consultancy. Manos: Bristol-Myers Squibb: Other: Travel and meetings. Hawkes: Specialised Therapeutics: Consultancy; Gilead: Membership on an entity's Board of Directors or advisory committees; Merck Sharpe Dohme: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Antigene: Membership on an entity's Board of Directors or advisory committees; Regeneron: Speakers Bureau; Bristol Myers Squib/Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Merck KgA: Research Funding; Astra Zeneca: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Roche: Membership on an entity's Board of Directors or advisory committees, Other: Travel and accommodation expenses, Research Funding, Speakers Bureau; Janssen: Speakers Bureau. Minson: Novartis: Research Funding; Hoffman La Roche: Research Funding. Dickinson: Celgene: Research Funding; Amgen: Honoraria; Takeda: Research Funding; Gilead Sciences: Consultancy, Honoraria, Speakers Bureau; MSD: Consultancy, Honoraria, Research Funding, Speakers Bureau; Janssen: Consultancy, Honoraria; Bristol-Myers Squibb: Consultancy, Honoraria; Roche: Consultancy, Honoraria, Other: travel, accommodation, expenses, Research Funding, Speakers Bureau; Novartis: Consultancy, Honoraria, Research Funding, Speakers Bureau. Øvlisen: Abbvie: Other: Travel expenses. Gregory: Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel fees, Speakers Bureau; Janssen: Consultancy; Novartis: Consultancy. Ku: Roche: Consultancy; Antegene: Consultancy; Genor Biopharma: Consultancy. Talaulikar: Roche: Honoraria, Research Funding; Jansenn: Honoraria, Research Funding; Amgen: Honoraria, Research Funding; Takeda: Honoraria, Research Funding; EUSA Pharma: Honoraria, Research Funding. Maurer: Pfizer: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene: Research Funding; Genentech: Research Funding; Kite Pharma: Membership on an entity's Board of Directors or advisory committees; Morphosys: Membership on an entity's Board of Directors or advisory committees, Research Funding; Nanostring: Research Funding. El-Galaly: Abbvie: Other: Speakers fee; ROCHE Ltd: Ended employment in the past 24 months. Cheah: Roche: Consultancy, Honoraria, Other: advisory and travel expenses, Research Funding; Janssen: Consultancy, Honoraria, Other: advisory; MSD: Consultancy, Honoraria, Other: advisory, Research Funding; Gilead: Consultancy, Honoraria, Other: advisory; Ascentage pharma: Consultancy, Honoraria, Other: advisory; Beigene: Consultancy, Honoraria, Other: advisory; AbbVie: Research Funding; Celgene: Research Funding; AstraZeneca: Consultancy, Honoraria, Other: advisory; Loxo/Lilly: Consultancy, Honoraria, Other: advisory; TG Therapeutics: Consultancy, Honoraria, Other: advisory.

Tam: Novartis: Honoraria; BeiGene: Honoraria; Roche: Honoraria; Janssen: Honoraria, Research Funding; AbbVie: Honoraria, Research Funding. Cull:Amgen: Other: Travel, accommodation ; Glycomimetics: Other: Travel, accommodation; AbbVie: Other: Travel, accommodation. Opat:Epizyme: Research Funding; CSL: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Consultancy, Research Funding; Novartis: Consultancy; Celgene: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; AbbVie: Consultancy, Honoraria, Research Funding; Mundipharma: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Beigene: Research Funding; Pharmacyclics LLC, an AbbVie Company: Research Funding; Amgen: Research Funding; Merck: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS: Consultancy, Honoraria. Gregory:Gilead: Membership on an entity's Board of Directors or advisory committees; Melbourne Haematology: Consultancy, Honoraria, Other: Travel fees and conference support, Speakers Bureau; Roche: Speakers Bureau; AbbVie: Other: grant pending, Research Funding; Celgene: Other: grant pending, Research Funding; Monash University: Research Funding; Beigene: Other: Grant pending, Research Funding; Janssen: Other: grant pending, Research Funding; MSD: Other: grant pending, Research Funding. Johnston:Roche: Consultancy, Membership on an entity's Board of Directors or advisory committees; Janssen, Roche: Membership on an entity's Board of Directors or advisory committees. Roncolato:St. George Hospital: Employment. Handunnetti:Gilead: Honoraria; Abbvie: Other: Travel Grant. Prince:Takeda: Consultancy, Honoraria; Celgene: Honoraria; Allergan: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria; Janssen: Consultancy, Honoraria. Li:Guangdong Province Hospital: Employment. Shih:BeiGene: Employment, Equity Ownership. Zhang:BeiGene: Employment, Equity Ownership. Wu:BeiGene: Employment, Equity Ownership. Liu:BeiGene: Employment, Equity Ownership. Huang:BeiGene: Employment, Equity Ownership. Trotman:BeiGene: Research Funding; Janssen: Research Funding; Celgene: Research Funding; Pharmacyclics: Research Funding; Roche: Research Funding.Zanubrutinib and tislelizumab are investigational agents and have not yet been approved in the US

Schuster: Novartis: Honoraria, Patents & Royalties: Combination CAR-T and PD-1 Inhibitors, Research Funding; Nordic Nanovector: Consultancy, Honoraria; AstraZeneca: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria, Research Funding; Pharmacyclics: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Acerta: Consultancy, Honoraria, Research Funding; Gilead: Consultancy, Honoraria, Research Funding; Loxo Oncology: Consultancy, Honoraria; Merck: Consultancy, Honoraria, Research Funding; Pfizer: Consultancy, Honoraria; Genentech: Consultancy, Honoraria, Research Funding. Bartlett:Bristol-Myers Squibb: Research Funding; Celgene: Research Funding; Kite Pharma: Research Funding; Merck: Research Funding; Millennium: Research Funding; Pfizer: Research Funding; Pharmacyclics: Research Funding; Gilead: Research Funding; Immune Design: Research Funding; Incyte: Research Funding; Janssen: Research Funding; ADC Therapeutics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Affimed: Research Funding; Autolus: Research Funding; Forty Seven: Research Funding; Genentech, Inc.: Research Funding. Assouline:Janssen: Consultancy, Honoraria, Speakers Bureau; F. Hoffmann-La Roche Ltd: Consultancy, Honoraria; Abbvie: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria, Speakers Bureau. Yoon:Kyowa Hako Kirin: Research Funding; Genentech, Inc.: Research Funding; Novartis: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; MSD: Consultancy; Janssen: Consultancy; Yuhan Pharma: Research Funding. Bosch:Kyte: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Acerta: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Celgene: Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Takeda: Honoraria, Research Funding; AstraZeneca: Honoraria, Research Funding; F. Hoffmann-La Roche Ltd/Genentech, Inc.: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Sehn:Acerta: Consultancy, Honoraria; Seattle Genetics: Consultancy, Honoraria; F. Hoffmann-La Roche/Genentech: Consultancy, Honoraria, Research Funding; Lundbeck: Consultancy, Honoraria; Kite Pharma: Consultancy, Honoraria; Lundbeck: Consultancy, Honoraria; Morphosys: Consultancy, Honoraria; F. Hoffmann-La Roche/Genentech: Consultancy, Honoraria, Research Funding; Apobiologix: Consultancy, Honoraria; Abbvie: Consultancy, Honoraria; Seattle Genetics: Consultancy, Honoraria; Kite Pharma: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Gilead: Consultancy, Honoraria; Verastem: Consultancy, Honoraria; Merck: Consultancy, Honoraria; Merck: Consultancy, Honoraria; TG Therapeutics: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Karyopharm: Consultancy, Honoraria; Morphosys: Consultancy, Honoraria; Abbvie: Consultancy, Honoraria; TEVA Pharmaceuticals Industries: Consultancy, Honoraria; Acerta: Consultancy, Honoraria; Janssen-Ortho: Consultancy, Honoraria; Janssen-Ortho: Honoraria; TG Therapeutics: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Astra Zeneca: Consultancy, Honoraria; TEVA Pharmaceuticals Industries: Consultancy, Honoraria; Astra Zeneca: Consultancy, Honoraria. Cheah:Janssen: Honoraria; Acerta: Honoraria; F. Hoffmann-La Roche Ltd: Honoraria, Research Funding; AbbVie: Research Funding; Celgene: Research Funding; Gilead: Honoraria; Loxo: Honoraria. Shadman:Mustang Biopharma: Research Funding; Gilead: Research Funding; AbbVIe: Consultancy, Research Funding; Genentech, Inc.: Consultancy, Research Funding; AstraZeneca: Consultancy; Sound Biologics: Consultancy; Pharmacyclics: Consultancy, Research Funding; ADC Therapeutics: Consultancy; Atara: Consultancy; Bigene: Research Funding; Celgene: Research Funding; TG Therapeutics: Research Funding; Verastem: Consultancy; Acerta: Research Funding; Emergent: Research Funding; Sunesis: Research Funding; Merck: Research Funding. Gregory:MSD: Other: grant pending, Research Funding; Beigene: Other: Grant pending, Research Funding; Celgene: Other: grant pending, Research Funding; Monash University: Research Funding; Roche: Speakers Bureau; Gilead: Membership on an entity's Board of Directors or advisory committees; AbbVie: Other: grant pending, Research Funding; Janssen: Other: grant pending, Research Funding; Melbourne Haematology: Consultancy, Honoraria, Other: Travel fees and conference support, Speakers Bureau. Wei:Genentech, Inc./F. Hoffmann-La Roche Ltd: Employment, Equity Ownership. Yin:Genentech, Inc: Employment, Equity Ownership. Kwan:Genentech, Inc: Employment, Equity Ownership. Yousefi:F. Hoffmann-La Roche Ltd: Employment. Hernandez:Genentech, Inc.: Employment, Equity Ownership. Li:F. Hoffmann-La Roche Ltd: Employment, Equity Ownership. O'Hear:F. Hoffmann-La Roche Ltd: Equity Ownership; Genentech, Inc.: Employment. Budde:F. Hoffmann-La Roche Ltd: Consultancy.Mosunetuzumab (RG7828) is a full-length, fully humanized immunoglobulin G1 (IgG1) bispecific antibody targeting both CD3 (on the surface of T cells) and CD20 (on the surface of B cells). Mosunetuzumab redirects T cells to engage and eliminate malignant B cells. Mosunetuzumab is an investigational agent.

Background:Zanubrutinib is an investigational, next-generation BTK inhibitor, designed to maximize BTK occupancy and minimize off-target inhibition of TEC- and EGFR-family kinases. It has been shown to be highly potent, selective, bioavailable, and irreversible with potentially advantageous pharmacokinetic and pharmacodynamic properties (Tam Blood2019). Tislelizumab is an investigational humanized IgG4 variant monoclonal antibody with high affinity and specificity for the programmed cell death-1 (PD-1) receptor, and was engineered to minimize binding to Fc-γ receptor on macrophages in order to mitigate macrophage-driven killing of effector T-cells, which may compromise the anti-tumor activity of PD-1 inhibitors (Friedlander ASCO 2017). Zanubrutinib and tislelizumab have shown encouraging efficacy as monotherapies in phase 2 studies in patients (pts) with hematologic cancers. PD-1/PD-L1 and B-cell receptor pathway inhibitors are being evaluated in combination for various B-cell malignancies, with the expectation of an additive or synergistic effect. Updated safety and preliminary efficacy data from a phase 1b trial are presented here.

Armand: Serventa: Research Funding; Sigma-Tau: Research Funding; Otsuka: Research Funding; Merck & Co.: Employment, Membership on an entity's Board of Directors or advisory committees, Other: Travel fees, gifts, and others, Research Funding; Roche: Research Funding; Pfizer Inc: Research Funding; Affimed: Research Funding; Bristol Myers Squibb Pharmaceuticals: Employment, Membership on an entity's Board of Directors or advisory committees, Other: Travel fees, gifts, and others, Research Funding; Infinity Pharmaceuticals: Employment, Membership on an entity's Board of Directors or advisory committees; Dana-Farber Cancer Institute: Employment. Zinzani:PORTOLA: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; ROCHE: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; SANDOZ: Membership on an entity's Board of Directors or advisory committees; SANOFI: Consultancy; CELGENE: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; EUSAPHARMA: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; KYOWA KIRIN: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; CELLTRION: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; GILEAD: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; JANSSEN-CILAG: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; BMS: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; SERVIER: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; IMMUNE DESIGN: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; MSD: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; VERASTEM: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Palcza:Merck & Co., Inc.: Employment, Other: Stock ownership. Healy:Merck & Co., Inc.: Employment, Other: Stock ownership. Nahar:Merck & Co., Inc.: Employment. Marinello:Merck & Co., Inc.: Employment, Other: Travel fees, gifts, and others; stock or other ownership. Gregory:Gilead: Membership on an entity's Board of Directors or advisory committees; AbbVie: Other: grant pending, Research Funding; Monash University: Research Funding; Janssen: Other: grant pending, Research Funding; Roche: Speakers Bureau; Beigene: Other: Grant pending, Research Funding; Melbourne Haematology: Consultancy, Honoraria, Other: Travel fees and conference support, Speakers Bureau; Celgene: Other: grant pending, Research Funding; MSD: Other: grant pending, Research Funding.

Background:The prognosis is poor for most patients with lymphoma who do not respond to initial therapy, leaving an unmet need for effective therapies for this patient population. Pembrolizumab, a programmed death 1 (PD-1) inhibitor, has shown clinically meaningful antitumor activity and manageable safety in multiple tumor types, including relapsed or refractory (R/R) classic Hodgkin lymphoma (R/R cHL) and R/R primary mediastinal large B-cell lymphoma. Results of preclinical studies have shown that lymphocyte activation gene-3 (LAG-3), a cell surface immunomodulatory receptor protein, is elevated in hematologic malignancies and that blockade of LAG-3 and the PD-1/PD ligand 1 (PD-L1) axis has synergistic antitumor activity in solid tumors. MK-4280 is a humanized anti-LAG-3 monoclonal antibody that blocks the interaction between LAG-3 and its ligand. The current study will evaluate the safety and efficacy of pembrolizumab combined with MK-4280 in patients with selected hematologic malignancies.

Introduction:Improved treatments are needed for relapsed or refractory (R/R) non-Hodgkin lymphoma (NHL) pts. Options are particularly limited for pts with B-cell NHLs who are R/R to CAR-T therapies or for whom a delay in effective therapy precludes this approach. Mosunetuzumab (M; RG7828) is a full-length, fully humanized immunoglobulin G1 (IgG1) bispecific antibody targeting both CD3 (on the surface of T cells) and CD20 (on the surface of B cells). In an ongoing Phase I/Ib study (GO29781; NCT02500407), promising efficacy and favorable tolerability were observed in R/R NHL pts (Budde et al. ASH 2018; Bartlett et al. ASCO 2019). We report complete remissions (CRs) with M in NHL pts who are R/R to CAR-T therapy, as well as activity with M re-treatment.

No relevant conflicts of interest to declare.

Stem cell self-renewal and lineage specification are highly dynamic and tightly controlled processes that are essential for normal haematopoiesis and are dysregulated in cancer. The X-linked BCL6 Corepressor(BCOR) gene encodes a protein that is widely expressed across adult human tissues and is a component of a non-canonical Polycomb repressive complex 1 (PRC1). The BCORgene is recurrently mutated in various malignant and non-malignant blood disorders, and we and others have recently provided experimental evidence that BCOR has cell-context dependent functions in regulating the proliferation, differentiation and survival of haematopoietic cells. To comprehensively examine the role of BCORin haematopoiesis in vivowe used a conditional mouse model that mimics the truncating mutations observed in acute myeloid leukaemia (AML) and myelodysplastic syndrome (MDS). Using stem and progenitor populations isolated ex vivowe comprehensively analysed the role of BCOR in regulating gene expression, modifying chromatin and altering genome architecture. We demonstrate that BCOR has a pivotal role in down-regulating haematopoietic stem cell (HSC) associated transcriptional networks during the transition from multi-potent stem cells to lineage-committed myeloid progenitors. Inactivation of Bcorin HSCs results in expansion of myeloid progenitors and co-operates with oncogenic KrasG12Din the initiation of an aggressive and fully transplantable acute leukaemia. Mechanistically, Bcor regulates a subset of PRC1-target genes including key HSC super-enhancer-linked transcription factors that are normally down-regulated during myeloid differentiation. We used CRISPR/Cas9 to explore the function of Bcor target genes and identified those that are necessary for the proliferation of Bcormutant leukaemic cells. This study provides a comprehensive mechanistic understanding of how BCOR regulates cell fate decisions and contributes to the development of leukaemia.

Introduction