Jain, Nitin

Abstract Richter’s syndrome (RS) arising from chronic lymphocytic leukemia (CLL) is a striking example of an aggressive malignant histology that emerges from indolent cancer. RS is a major barrier to disease control in CLL and is associated with poor clinical outcomes and limited survival. The genetic basis of RS is poorly understood, and its relationship to the antecedent CLL remains incompletely characterized. To study RS, we performed whole-exome sequencing (WES) on samples collected from 52 patients with RS of diffuse large B cell lymphoma (DLBCL) histology. For this genomic characterization, samples from 42 patients were analyzed as ‘trios’ (matched germline, CLL and RS tissue DNA) and those from 10 as ‘duos’ (matched CLL and RS DNA). Beyond addressing contamination of CLL DNA in the germline sample, we developed methods for discriminating between the RS and CLL clones which often coexist in the same samples. The discovery cohort revealed that RS and CLL were clonally-related in 45/52 (87%) cases based on WES analysis, with a distinct RS clone emerging from a CLL subclone. The remaining 13% were determined to be clonally unrelated. RS clones presented ~3x higher rates of additional mutations than the ancestral CLL clones from which they developed. We identified novel RS somatic driver mutations (in IRF2BP2, SRSF1, B2M, DNMT3A and others), a high rate of copy number variations with recurrent deletions (e.g., del(17p) [TP53], del(13q14.3), del(7q36), and del(15q13.11) [MGA], del(9p21.3) [CDKN2A/B], del(16q12.2)), focal amplifications (amp(7q21.2) [CDK6], amp(8q24.2) [RECQL4, MYC], amp(13q31.2) [ERCC5], and frequent whole genome duplication. To further investigate RS and CLL clonal evolution, we performed single-cell RNA-sequencing on biopsies at the time of RS diagnosis in 5 individuals with clonally related transformation. Using our novel tool, CNVSingle, we inferred allele specific single-cell copy number alterations, yielding cluster-specific copy number profiles that matched the WES results of individual subclones of the RS and CLL populations. This enabled mapping genetic clones to specific expression patterns. Finally, we devised and tested a methodology that uses cfDNA for early detection of emerging Richter’s disease and have successfully identified Richter‘s tumor DNA in the blood several months prior to the clinical diagnosis. Our study thus defines drivers, distinct molecular subtypes and evolutionary path to RS and suggests strategies for its improved detection. Citation Format: Erin M. Parry, Ignaty Leshchiner, Romain Guièze, Connor Johnson, Eugen Tausch, Sameer Parikh, Camilla Lemvigh, Conor Messer, Daniel Rosebrock, Filippo Utro, Chaya Levovitz, Kahn Rhrissorrakrai, Matthew Davids, Raquel A. Jacobs, Kara Slowik, Julien Broseus, Shanye Yin, Shuqiang Li, Geoff Fell, Ziao Lin, Binyamin A. Knisbacher, Neil Ruthen, Dimitri Livitz, Christof Schneider, Jialin Ma, Julian Hess, Laura Z. Rassenti, Thomas J. Kipps, Nitin Jain, William Wierda, Florence Cymbalista, Neil E. Kay, Kenneth J. Livak, Brian P. Danysh, Chip Stewart, Donna Neuberg, Jennifer R. Brown, Laxmi Parida, Stephan Stilgenbauer, Gad Getz, Catherine J. Wu. Evolutionary history of transformation from chronic lymphocytic leukemia to Richter’s syndrome [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 4007.

Abstract Introduction: The management of CLL patients historically utilized FD chemoimmunotherapy (CIT), including fludarabine, cyclophosphamide and rituximab (FCR), or bendamustine and rituximab (BR). That changed with the introduction of Bruton Tyrosine Kinase inhibitors (BTKi) as an option for oral targeted monotherapy delivered continuously until disease progression or intolerance. Recently, novel combinations that include a B-cell lymphoma 2 inhibitor (BCL2i), such as venetoclax, have been developed as FD therapy. In addition, though not FDA approved, MRD assessment is emerging as a potential tool to guide FD therapy. Understanding the patient and their caregiver perspectives on FD and MRD is critical to providing the best care. Methods: CLL Society developed a web-based survey instrument of multiple-choice questions to assess patient and caregiver awareness, understanding, and preferences with MRD and FD therapies, where FD referred to both time and MRD guided limited duration therapies. Patients and caregivers were invited to participate via message boards, CLL Society's website, email, and online communities. Results: A total of 607 (96%) self-identified US patients and 36 (5%) caregivers, who answered on behalf of patients in their care, completed the survey between 31/AUG/2020 and 31/JAN/2021. The mean patient age was 64 (range, 30-90) years, 54% were female, 169 patients (27%) treatment-naïve, 239 (38%) with one line of prior therapy, and 214 (34%) with two or more. Targeted agents (e.g., venetoclax, ibrutinib, acalabrutinib, idelalisib, and duvelisib) had been used by 401 (64%). FD use with some novel therapies was known of by 565 (90%) patients, while 588 (93%) knew some were used as continuous daily treatment until disease progression or intolerance. If effectiveness and side effects were assumed similar, 485 (77%) preferred FD, and 398 (63%) wanted that finite treatment to be guided by MRD status. Only 42 (7%) preferred continuous therapy until disease progression or intolerance. The chance for continued remission while off treatment was ranked as a very important potential benefit after stopping a FD therapy by 581 (92%) patients. When considering therapy, 589 (93%), 575 (91%), 447 (71%), 415 (66%), 302 (48%), and 288 (46%) rated having overall survival, having future therapeutic options, avoiding chemotherapy, the ability to reach undetectable (u)MRD, minimal lab and office visits, and FD therapy as very important, respectively (Fig. 1). Being tested for MRD at least once was reported by 215 (34%), while 327 (52%) had not been tested, and 88 (14%) were unsure. There were 562 (89%) who were somewhat or very familiar with the term MRD, while 450 (71%) were confident of understanding what MRD testing measures, and 446 (70%) understood its role in CLL. Only 225 (36%) stated they understood different testing methods. While self-rated understanding of the indications for MRD testing was relatively high, some wanted testing done when not clinically indicated, such as when there was persistent CLL by routine laboratory findings, or at the time of diagnosis (Fig. 2). Respondents were mixed in their stated understanding as to which therapies could result in uMRD, with 241 (38%), 197 (32%), and 195 (32%) not knowing if CIT, BCL2i, and BTKi, could lead to uMRD, respectively. Two hundred and sixty-five (42%), 84 (13%), and 57 (9%) believed it was possible for most on a BCL2i, BTKi, or CIT to achieve uMRD, respectively (Fig. 3). If patients had evidence of MRD at the end of treatment, 365 (58%) would request frequent monitoring but would make no immediate treatment decisions based on MRD status, 279 (44%) were unsure, and only 88 (14%) would want further treatment immediately. Conclusions: The results from this patient-based study reveal a high awareness of FD therapies and MRD testing, as well as a clear preference for FD among internet-active patients and caregivers. However, there are gaps in the knowledge base, thus significant educational opportunities. Limitations included the opt-in sample where the survey results may not be projectable to the total CLL population. Moreover, the survey was not designed to assess preferences if either FD or continuous therapy offered improved outcomes. Nonetheless, as the potential role of MRD and FD therapy grows in CLL it will be incumbent on clinicians to ensure patients are well informed and engaged to help them better share therapeutic decisions. Figure 1 Figure 1. Disclosures Koffman: AbbVie: Current equity holder in publicly-traded company; AstraZeneca: Current equity holder in publicly-traded company, Honoraria; Beigene: Current equity holder in publicly-traded company; Bristol Myer Squibb: Current equity holder in publicly-traded company, Honoraria; Gilead: Current equity holder in publicly-traded company; Johnson & Johnson: Current equity holder in publicly-traded company, Honoraria; Sunesis Pharmaceuticals: Current equity holder in publicly-traded company; TG Therapeutics: Current equity holder in publicly-traded company; Regeneron: Current equity holder in publicly-traded company; Miragen Therapeutics: Current equity holder in publicly-traded company; Novartis: Membership on an entity's Board of Directors or advisory committees; Portola Pharma: Current equity holder in publicly-traded company; MEI Pharma: Current equity holder in publicly-traded company; Merck: Current equity holder in publicly-traded company. Stewart: Johnson & Johnson: Current equity holder in publicly-traded company; Novartis: Current equity holder in publicly-traded company; Dr. Reddy's Laboratories Limited: Current equity holder in publicly-traded company; Adaptive Biotechnologies: Current equity holder in publicly-traded company; Pacific Biosciences: Current equity holder in publicly-traded company. Byrd: Novartis, Trillium, Astellas, AstraZeneca, Pharmacyclics, Syndax: Consultancy, Honoraria; Vincerx Pharmaceuticals: Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Newave: Membership on an entity's Board of Directors or advisory committees. Danilov: Bayer Oncology: Consultancy, Honoraria, Research Funding; Genentech: Consultancy, Honoraria, Research Funding; Takeda Oncology: Research Funding; Rigel Pharm: Honoraria; TG Therapeutics: Consultancy, Research Funding; Abbvie: Consultancy, Honoraria; Beigene: Consultancy, Honoraria; Pharmacyclics: Consultancy, Honoraria; Gilead Sciences: Research Funding; Bristol-Meyers-Squibb: Honoraria, Research Funding; SecuraBio: Research Funding; Astra Zeneca: Consultancy, Honoraria, Research Funding. Davids: BeiGene: Consultancy; Janssen: Consultancy; Ascentage Pharma: Consultancy, Research Funding; Novartis: Consultancy, Research Funding; Astra-Zeneca: Consultancy, Research Funding; Pharmacyclics: Consultancy, Research Funding; BMS: Consultancy, Research Funding; MEI Pharma: Consultancy, Research Funding; Genentech: Consultancy, Research Funding; Adaptive Biotechnologies: Consultancy; AbbVie: Consultancy; Surface Oncology: Research Funding; TG Therapeutics: Consultancy, Research Funding; Celgene: Consultancy; Verastem: Consultancy, Research Funding; Eli Lilly and Company: Consultancy; MEI Pharma: Consultancy; Merck: Consultancy; Research to Practice: Consultancy; Takeda: Consultancy. Furman: Beigene: Consultancy; Acerta/AstraZeneca: Consultancy; Janssen: Consultancy, Honoraria; Sunesis: Consultancy; Genentech: Consultancy; Incyte: Consultancy; Pharmacyclics: Consultancy; TG Therapeutics: Consultancy; Loxo Oncology: Consultancy; Sanofi: Consultancy; Morphosys: Consultancy; Verastem: Consultancy; X4 Pharmaceuticals: Consultancy; Oncotracker: Consultancy; Abbvie: Consultancy, Honoraria, Other: Expert testimony; AstraZeneca: Honoraria. Jain: Bristol Myers Squibb: Honoraria, Research Funding; Genentech: Honoraria, Research Funding; AstraZeneca: Honoraria, Research Funding; Fate Therapeutics: Research Funding; Beigene: Honoraria; AbbVie: Honoraria, Research Funding; Pfizer: Research Funding; TG Therapeutics: Honoraria; Cellectis: Honoraria, Research Funding; Precision Biosciences: Honoraria, Research Funding; ADC Therapeutics: Honoraria, Research Funding; Aprea Therapeutics: Research Funding; Adaptive Biotechnologies: Honoraria, Research Funding; Servier: Honoraria, Research Funding; Janssen: Honoraria; Incyte: Research Funding; Pharmacyclics: Research Funding. Kay: Oncotracker: Membership on an entity's Board of Directors or advisory committees; Genentech: Research Funding; Targeted 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; Acerta Pharma: Research Funding; MEI Pharma: Research Funding; 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; AstraZeneca: Membership on an entity's Board of Directors or advisory committees; Rigel: 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; Janssen: Membership on an entity's Board of Directors or advisory committees; Dava Oncology: 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; Bristol Meyer Squib: Membership on an entity's Board of Directors or advisory committees, Research Funding; Agios Pharm: Membership on an entity's Board of Directors or advisory committees; TG Therapeutics: Research Funding; Sunesis: Research Funding; Juno Therapeutics: 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. Lamanna: Juno Therapeutics, Inc.: Research Funding; BeiGene: Consultancy; AstraZeneca: Consultancy, Research Funding; AbbVie: Consultancy, Research Funding; MingSight Pharmaceuticals, Inc.: Research Funding; Genentech, Inc.: Consultancy, Research Funding; Gilead Sciences, Inc.: Consultancy; TG Therapeutics, Inc: Research Funding; Verastem Oncology: Research Funding; Celgene Corporation: Consultancy; Oncternal Therapeutics: Research Funding; Pharmacyclics: Consultancy; Janssen Pharmaceuticals, Inc.: Consultancy. Mato: MSKCC: Current Employment; Pharmacyclics LLC, an AbbVie Company: Consultancy, Research Funding; TG Therapeutics: Consultancy, Other: DSMB, Research Funding; Nurix: Research Funding; BeiGene: Consultancy, Research Funding; Janssen: Consultancy, Research Funding; LOXO: Consultancy, Research Funding; Genmab: Research Funding; AstraZeneca: Consultancy; Sunesis: Consultancy, Research Funding; DTRM BioPharma: Consultancy, Research Funding; Acerta/AstraZeneca: Consultancy, Research Funding; Johnson and Johnson: Consultancy, Research Funding; AbbVie: Consultancy, Research Funding; Adaptive Biotechnologies: Consultancy, Research Funding; Genentech: Consultancy, Research Funding. Ujjani: Adaptive Biotechnologies: Research Funding; Atara Bio: Consultancy; Janssen: Consultancy; Epizyme: Consultancy, Membership on an entity's Board of Directors or advisory committees; TG Therapeutics: Honoraria; Gilead: Honoraria; ACDT: Honoraria; Kite, a Gilead Company: Honoraria; Loxo: Research Funding; AstraZeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; AbbVie: Consultancy, Research Funding; Pharmacyclics: Consultancy, Research Funding. Pagel: Kite, a Gilead Company: Consultancy; Incyte/MorphoSys: Consultancy; AstraZeneca: Consultancy; Actinium Pharmaceuticals: Consultancy; Gilead: Consultancy; Pharmacyclics/AbbVie: Consultancy; MEI Pharma: Consultancy; Epizyme: Consultancy; BeiGene: Consultancy.

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.

AbstractThe progress with intensive chemotherapy and supportive care measures has improved survival in patients with newly diagnosed acute myeloid leukemia (AML). Given the recent development of effective low intensity therapies, an optimal decision on the therapy intensity may improve survival through the avoidance of early mortality. We reviewed the outcome of 3728 patients with newly diagnosed AML who received intensive chemotherapy between August 1980 and May 2020. Intensive chemotherapy was defined as a cumulative cytarabine dose ≥ 700 mg/m2 during induction therapy. We divided the whole cohort into a training and validation group at a 3:1 ratio. The population was divided into a training (2790 patients) and a validation cohort (938 patients). The median age was 55 years (range, 15‐99). Among them, 442 patients (12%) had core‐binding factor AML. Binary logistic regression identified older age, worse performance status, hyperbilirubinemia, elevated creatinine, hyperuricemia, cytogenetic abnormalities other than CBF and ‐Y, and pneumonia as adverse prognostic factors for an early 4‐week mortality. This risk classification for early mortality was verified in the validation cohort of patients. In the validation cohort of more recently treated patients from 2000 to 2017, the 4‐week mortality rates with intensive chemotherapy were 2%, 14%, and 50% in the low‐, high‐, and very high‐risk group, respectively. The mortality rates with low intensity therapies were 3%, 9%, and 20%, respectively. The risk classification guides treatment intensity by the assessment of age, frailty, organ dysfunction, cytogenetic abnormality, and infection to avoid early mortality.

The NCCN Guidelines for Acute Lymphoblastic Leukemia (ALL) focus on the classification of ALL subtypes based on immunophenotype and cytogenetic/molecular markers; risk assessment and stratification for risk-adapted therapy; treatment strategies for Philadelphia chromosome (Ph)-positive and Ph-negative ALL for both adolescent and young adult and adult patients; and supportive care considerations. Given the complexity of ALL treatment regimens and the required supportive care measures, the NCCN ALL Panel recommends that patients be treated at a specialized cancer center with expertise in the management of ALL This portion of the Guidelines focuses on the management of Ph-positive and Ph-negative ALL in adolescents and young adults, and management in relapsed settings.

Background: Autologous T cells engineered to express a chimeric antigen receptor (CAR) targeting the B-cell lineage antigen CD19 (CAR19) in patients with relapsed/refractory (r/r) aggressive B-cell lymphomas (BCL) and pre-B acute lymphoblastic leukemia (B-ALL) have resulted in transformative improvements in clinical outcomes. However, there remain significant limitations concerning autologous CAR19 T cell manufacturing, including dysfunctional starting material, lack of product consistency and purity following genetic engineering, manufacturing timelines that necessitate the administration of bridging therapy in patients with aggressive disease, and insufficient quantities of CAR19 T cells, especially in severely cytopenic patients, to allow for more than single-dose administration routinely. The ability to consistently administer more than a single dose of CAR19 T cells enables dosing schedules that may reduce the risk of potentially life-threatening toxicities such as cytokine release syndrome and neurotoxicity, while maintaining or improving the depth and durability of anti-tumor responses. FT819 is a first-of-kind, off-the-shelf CAR19 T cell product candidate derived from a clonal master engineered induced pluripotent stem cell (iPSC) line, which can be used as a renewable source for the mass production of off-the-shelf CAR T cells for broad patient access. FT819 is engineered with the following features designed to improve the safety and efficacy of CAR T cell therapy: a novel 1XX CAR signaling domain, which has been shown to extend T cell effector function without eliciting exhaustion; integration of the CAR transgene directly into the T cell receptor alpha constant (TRAC) locus, which has been shown to promote uniform CAR expression and enhanced T cell potency; and complete bi-allelic disruption of T cell receptor (TCR) expression for the prevention of graft-versus-host disease (GVHD). FT819 has demonstrated antigen-specific cytolytic activity in vitro against CD19-expressing leukemia and lymphoma cell lines comparable to that of donor-derived CAR T cells, and persists and maintains tumor clearance in the bone marrow in an in vivo disseminated xenograft model of lymphoblastic leukemia (Mandal et al. 2020). The properties of FT819 and its ability to improve outcomes of patients with B-cell malignancies warrants further clinical investigation. Study Design and Methods: This study is a multicenter, Phase I clinical trial of FT819 in patients with r/r B-cell malignancies, including BCL, chronic lymphocytic leukemia (CLL), and B-ALL. The primary objective of the trial is to determine the recommended Phase II dose of FT819. Key secondary objectives include evaluation of FT819 safety and tolerability, anti-tumor activity, and pharmacokinetics (PK). Exploratory objectives include characterization of FT819 pharmacodynamics as assessed by peripheral blood biomarkers, and by phenotypic and genetic characterization of the tumor microenvironment from paired pre- and post-treatment tumor biopsies. The dose-escalation part of the trial utilizes a 3+3 dose-escalation design to identify the maximum tolerated dose for BCL, CLL, and B-ALL. The dose-expansion part of the trial is designed to further characterize the safety, efficacy, and PK of FT819 in multiple indications. Up to a maximum of 300 patients will be enrolled. The trial will test up to four FT819 dose levels ranging from 30 to 900 million cells. Three FT819 dosing regimens each will be tested for BCL, CLL, and B-ALL: Regimen A, FT819 administered as a single dose; Regimen A1, FT819 administered as a single dose in combination with interleukin (IL)-2; and Regimen B, FT819 administered as fractionated doses on Days 1, 3, and 5. Lympho-conditioning will consist of three consecutive days of fludarabine and cyclophosphamide administered prior to the first dose of FT819. Key inclusion criteria include r/r disease after standard approved therapies, documented CD19 expression, and adequate organ function. Key exclusion criteria include ongoing immunosuppression such as systemic GVHD therapy, prior allograft organ transplant, active central nervous system involvement of disease, and known allergy to FT819 components. The trial is expected to begin patient recruitment in 2020. Disclosures Park: Novartis: Consultancy; Fate Therapeutics: Research Funding; Amgen: Consultancy, Research Funding; Genentech/Roche: Research Funding; Kite: Consultancy, Research Funding; Incyte: Consultancy, Research Funding; GSK: Consultancy; Autolus: Consultancy, Research Funding; Intellia: Consultancy; Minverva: Consultancy; Takeda: Consultancy, Research Funding; AstraZeneca: Consultancy; Servier: Consultancy, Research Funding; Allogene: Consultancy; Juno Therapeutics: Research Funding; Artiva: Membership on an entity's Board of Directors or advisory committees. Jain:Pfizer: Research Funding; ADC Therapeutics: Research Funding; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Incyte: Research Funding; Servier: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS: Research Funding; AbbVie: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Adaptive Biotechnologies: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; TG Therapeutics: Honoraria, Membership on an entity's Board of Directors or advisory committees; Aprea Therapeutics: Research Funding; BeiGene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Genentech: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Precision Bioscienes: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; AstraZeneca: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Fate Therapeutics: Research Funding; Verastem: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Cellectis: Research Funding; Pharmacyclics: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. McGuirk:Bellicum Pharmaceutical: Research Funding; Gamida Cell: Research Funding; Astellas: Research Funding; Pluristem Ltd: Research Funding; Novartis: Research Funding; Juno Therapeutics: Consultancy, Honoraria, Research Funding; Kite Pharmaceuticals: Consultancy, Honoraria, Research Funding, Speakers Bureau; Fresenius Biotech: Research Funding; Allo Vir: Consultancy, Honoraria, Research Funding. Diaz:Fate Therapeutics, Inc.: Current Employment. Valamehr:Fate Therapeutics, Inc: Current Employment, Current equity holder in publicly-traded company. Chu:Fate Therapeutics, Inc.: Current Employment, Current equity holder in publicly-traded company; Roche Holding AG: Current equity holder in publicly-traded company. Castro:Kite Pharma: Research Funding; Pharmacyclics: Research Funding; Fate Therapeutics: Research Funding. OffLabel Disclosure: Cyclophosphamide and fludarabine will be used as lympho-conditioning therapy prior to FT819 administration. IL-2 will be administered in order to promote the expansion and function of FT819 as a T-cell product.

Richter's syndrome (RS) arising from chronic lymphocytic leukemia (CLL) is a striking example of an aggressive malignant histology that emerges from indolent cancer. A major barrier to disease control in CLL, RS is associated with poor clinical outcomes and limited survival. The genetic basis of RS is poorly understood and its relationship to antecedent CLL remains incompletely characterized. Notable challenges to the genomic study of RS includes those of sample acquisition, the distinction between true tumor events rather than sequence artifacts in archival fixed tissue, and the limitations of available computational techniques for deconvoluting admixtures of CLL and RS DNA within the same biopsy specimen. To address these challenges and characterize the genetic profile of RS, we performed whole-exome sequencing (WES) on samples collected from 42 patients with RS of diffuse large B cell lymphoma (DLBCL) histology. For this genomic characterization, samples from 37 patients were analyzed as 'trios' (matched germline, CLL and RS tissue DNA) and those from 5 as 'duos' (matched CLL and RS DNA). CLL diagnosis preceeded RS diagnosis by a median of 60.6 months (range 0.1-234.5). The median number of prior CLL-directed therapies was 2 (range 0-10). 8 patients had no prior CLL-directed therapy, while 9 were exposed to novel agents. The median time from most proximal CLL sampling to RS was 2.7 months (range: 82.2 months pre- to 3.8 months post RS diagnosis). Critical analytic innovations applied to this dataset included addressing contamination of CLL DNA in the germline sample (through the tool DeTIN) and generating the ability to discriminate between clones arising from RS or from CLL, even while both histologies were commonly co-existing within originating biopsies (via the tool PhylogicNDT). From this discovery cohort of 42 cases, 36 (86%) revealed RS and CLL to be clonally-related based on WES analysis, with a distinct RS clone emerging from an existing CLL subclone. Of the 6 (14%) cases determined to be clonally unrelated by WES, 4 had been previously examined by IGHV sequencing; only 1 of 4 was categorized as clonally unrelated, likely due to CLL and RS admixture. RS displayed mutational signatures reflecting aging (CpG), canonical AID, and non-canonical AID processes. Through deconvoluting clonal composition using PhylogicNDT in related sample trios (n=31), we established several notable differences compared to antecedent CLL. First, RS clones presented higher rates of additional mutations than the ancestral CLL clones from which they developed (2.47 vs. 0.86 Mut/Mb, p<0.0001). Second, the frequency of CLL-associated driver mutations in the RS clones was altered:TP53 mutation (n=21, 50%), NOTCH1 mutation (n=17, 40%) NFKBIE (n=5, 12%), EGR2 (n=6, 14%), XPO1 (n=5, 12%), and RPS15 (n=3, 7%). Third, the clonal transition to RS was marked by a diversity of additional driver mutations and particularly increased copy number variants (CNVs). RS biopsies had recurrent arm level events, including del(17p) in 44%, del(4p) in 27%, del(4q) in 27%, del(9p) in 22%, del(17q) in 22% and del(9q) in 20% (Q<0.05, GISTIC). The top focal alterations in RS biopsies, as identified by tool GISTIC included (Q value <= 0.05): amp(7q21.2) - CDK6,amp(8q24.3) - RECQL4, amp(13q31.3) - ERCC5, amp(19p13.3), amp(19q13.42), del(8p12), del(17p13.1) - TP53, del(13q14.3), del(7q35), and del(16q12.2). Finally, whole genome doubling was observed in 6 cases upon transition to RS. To further investigate RS and CLL clonal evolution at high resolution, we performed single-cell RNA-sequencing (10x Genomics), on biopsies at the time of RS diagnosis in 5 individuals with clonally related transformation. Data analysis and clustering was conducted using Seurat(v3) with doublet removal (DoubletFinder). We identified CNV in single-cell transcriptomes that matched the WES copy-number profiles of individual subclones of the RS and CLL populations and thus linked subclones identified by WES to single-cell expression clusters and states, revealing CLL, RS and intermediate evolutionary cell states. In conclusion, we identify that RS arises from CLL subclones through distinct mutational trajectories. Further molecular subclassification of RS, including genetic characterization of additional cases, and linking mutational data with clinical outcomes is ongoing and has potential to alter clinical classification and prognostication of RS. Disclosures Guieze: abbvie: Honoraria, Other: advisory board, travel funds; janssen cilag: Honoraria, Other: advisory board, travel funds; roche: Other: travle funds; gilead: Honoraria, Other: travel funds; astrazanecka: Honoraria, Other: advisory board. Leshchiner:PACT Pharma, Inc.: Consultancy. Tausch:Roche: Consultancy, Honoraria, Research Funding; AbbVie: Consultancy, Honoraria, Research Funding; Janssen-Cilag: Consultancy, Honoraria, Research Funding. Davids:Genentech: Consultancy, Research Funding; Janssen: Consultancy; Gilead Sciences: Consultancy; Novartis: Consultancy, Research Funding; MEI Pharma: Consultancy, Research Funding; Surface Oncology: Research Funding; AbbVie: Consultancy; Adaptive Biotechnologies: Consultancy; Merck: Consultancy; Pharmacyclics: Consultancy, Research Funding; TG Therapeutics: Consultancy, Research Funding; Verastem: Consultancy, Research Funding; Syros Pharmaceuticals: Consultancy; Sunesis: Consultancy; Zentalis: Consultancy; AstraZeneca: Consultancy, Research Funding; Ascentage Pharma: Consultancy, Research Funding; Eli Lilly: Consultancy; Research to Practice: Honoraria; Celgene: Consultancy; BeiGene: Consultancy; Bristol Myers Squibb: Research Funding. Elagina:AbbVie: Current Employment. Jain:TG Therapeutics: Honoraria, Membership on an entity's Board of Directors or advisory committees; Servier: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Precision Bioscienes: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Incyte: Research Funding; Pfizer: Research Funding; AbbVie: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Pharmacyclics: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Fate Therapeutics: Research Funding; Verastem: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS: Research Funding; Cellectis: Research Funding; BeiGene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Aprea Therapeutics: Research Funding; Genentech: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Adaptive Biotechnologies: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; ADC Therapeutics: Research Funding; AstraZeneca: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Kipps:Oncternal Therapeutics, Inc.: Other: Cirmtuzumab was developed by Thomas J. Kipps in the Thomas J. Kipps laboratory and licensed by the University of California to Oncternal Therapeutics, Inc., which provided stock options and research funding to the Thomas J. Kipps laboratory, Research Funding; Celgene: Honoraria, Research Funding; Gilead: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Genentech/Roche: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; VelosBio: Research Funding; Pharmacyclics/ AbbVie, Breast Cancer Research Foundation, MD Anderson Cancer Center, Oncternal Therapeutics, Inc., Specialized Center of Research (SCOR) - The Leukemia and Lymphoma Society (LLS), California Institute for Regenerative Medicine (CIRM): Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Ascerta/AstraZeneca, Celgene, Genentech/F. Hoffmann-La Roche, Gilead, Janssen, Loxo Oncology, Octernal Therapeutics, Pharmacyclics/AbbVie, TG Therapeutics, VelosBio, and Verastem: Membership on an entity's Board of Directors or advisory committees. Broséus:Novartis: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; AstraZeneca: Consultancy, Honoraria; Gilead: Honoraria. Kay:MEI Pharma: Research Funding; Cytomx: Membership on an entity's Board of Directors or advisory committees; Abbvie: Research Funding; Tolero Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Research Funding; Bristol Meyer Squib: Membership on an entity's Board of Directors or advisory committees, Research Funding; Acerta Pharma: Research Funding; Pharmacyclics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Juno Theraputics: Membership on an entity's Board of Directors or advisory committees; Dava Oncology: Membership on an entity's Board of Directors or advisory committees; Oncotracker: Membership on an entity's Board of Directors or advisory committees; Rigel: Membership on an entity's Board of Directors or advisory committees; Agios Pharma: Membership on an entity's Board of Directors or advisory committees; Astra Zeneca: Membership on an entity's Board of Directors or advisory committees; Sunesis: Research Funding; Morpho-sys: Membership on an entity's Board of Directors or advisory committees. Purroy:AstraZenica: Current Employment. Utro:IBM: Current Employment. Rhrissorrakrai:IBM: Current Employment. Levovitz:IBM: Current Employment. Parikh:GlaxoSmithKline: Honoraria; Pharmacyclics: Honoraria, Research Funding; AstraZeneca: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; MorphoSys: Research Funding; TG Therapeutics: Research Funding; Merck: Research Funding; AbbVie: Honoraria, Research Funding; Ascentage Pharma: Research Funding; Genentech: Honoraria; Verastem Oncology: Honoraria. Brown:Abbvie, Acerta, AstraZeneca, Beigene, Invectys, Juno/Celgene, Kite, Morphosys, Novartis, Octapharma, Pharmacyclics, Sunesis, TG Therapeutics, Verastem: Consultancy; Gilead, Loxo, Sun, Verastem: Research Funding; Janssen, Teva: Speakers Bureau. Parida:IBM: Current Employment. Neuberg:Madrigak Pharmaceuticals: Current equity holder in publicly-traded company; Pharmacyclics: Research Funding; Celgene: Research Funding. Stilgenbauer:Novartis: Consultancy, Honoraria, Other, Research Funding; Mundipharma: Consultancy, Honoraria, Other, Research Funding; Janssen-Cilag: Consultancy, Honoraria, Other: travel support, Research Funding; Gilead: Consultancy, Honoraria, Other: travel support, Research Funding; GlaxoSmithKline: Consultancy, Honoraria, Other: travel support, Research Funding; Genentech: Consultancy, Honoraria, Other: travel support, Research Funding; Genzyme: Consultancy, Honoraria, Other: travel support, Research Funding; Pharmacyclics: Consultancy, Honoraria, Other, Research Funding; Boehringer-Ingelheim: Consultancy, Honoraria, Other: travel support, Research Funding; Celgene: Consultancy, Honoraria, Other: travel support, Research Funding; F. Hoffmann-LaRoche: Consultancy, Honoraria, Other: travel support, Research Funding; Amgen: Consultancy, Honoraria, Other: travel support, Research Funding; AbbVie: Consultancy, Honoraria, Other: travel support, Research Funding. Getz:Scorpion Therapeutics: Consultancy, Current equity holder in publicly-traded company, Other: Founder; IBM: Research Funding; Pharmacyclics: Research Funding; Broad Institute: Patents & Royalties: MuTect, ABSOLUTE, MutSig, MSMuTect, MSMutSig, POLYSOLVER and TensorQTL. Wu:Pharmacyclics: Research Funding; BionTech: Current equity holder in publicly-traded company.

Key Points An incidental histologic diagnosis of DLBCL was identified during temporary interruption of ibrutinib treatment in patients with CLL. In contrast to an aggressive clinical course typical of Richter transformation, these patients responded to reinitiation of ibrutinib alone.

Abstract Background: Trabectedin is an FDA-approved DNA minor groove binder (MGB) that has activity against translocation-associated sarcomas. Lurbinectedin is a next-generation MGB with pre-clinical activity against myeloid leukemia cells. A dose-finding phase 1 clinical trial was performed in patients with acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) with further assessment of safety and tolerability. Methods: Forty-two patients with relapsed/refractory AML/MDS received lurbinectedin administered as a 1-hour intravenous infusion in a 3+3 study design. Two dosing schedules were used: 3.5 mg, 5 mg, 7 mg, or 6 mg on days 1 and 8 or 2 mg, 3 mg, 1 mg, or 1.5 mg for 3 consecutive days on days 1 to 3. Patients 18 years or older with a diagnosis of advanced, relapsed/refractory AML (non-acute promyelocytic leukemia) and MDS were eligible and treated on study. Eligible patients had adequate hepatic, renal, and cardiac function and an Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 2. Patients with uncontrolled infection, human immunodeficiency virus, cardiac and neurological disorders, or those who were pregnant were ineligible. Clinical trial information: NCT01314599. Results: Three patients experienced dose-limiting toxicities of rhabdomyolysis (grade 4), hyperbilirubinemia (grade 3), and oral herpes (grade 3) with the days 1 and 8 schedule. Otherwise, adverse events mainly consisted of gastrointestinal manifestations (n=11), febrile neutropenia/infections (n=4), pulmonary toxicity (n=2), and renal failure (n=2). The most common laboratory abnormalities observed were an increase in creatinine (93%) and anemia, neutropenia, and thrombocytopenia (100%). Overall, 33 of 42 patients (79%) had reduction in blasts in peripheral blood or bone marrow. One patient achieved a partial response and two patients a morphologic leukemia-free state. Most (n=30, 71%) were discontinued due to progressive disease. Early deaths occurred from disease-related causes that were not attributable to lurbinectedin. Four patients with a chromosome 11q21-23 abnormality had significantly greater bone marrow blast reduction than those without such abnormality, with decrease of 31±14% (n=4) vs. 8±8% (n=16), respectively (P=0.04). Conclusions: Overall, lurbinectedin was safe and tolerated using the schedules and dose levels tested. While no sustained remissions were observed, single-agent lurbinectedin was transiently leukemia suppressive for some patients. Disclosures Rodríguez: PharmaMar: Employment. Ravandi:Bristol-Myers Squibb: Research Funding; Jazz: Honoraria; Abbvie: Research Funding; Seattle Genetics: Research Funding; Abbvie: Research Funding; Amgen: Honoraria, Research Funding, Speakers Bureau; Orsenix: Honoraria; Seattle Genetics: Research Funding; Astellas Pharmaceuticals: Consultancy, Honoraria; Sunesis: Honoraria; Orsenix: Honoraria; Macrogenix: Honoraria, Research Funding; Astellas Pharmaceuticals: Consultancy, Honoraria; Jazz: Honoraria; Xencor: Research Funding; Bristol-Myers Squibb: Research Funding; Amgen: Honoraria, Research Funding, Speakers Bureau; Macrogenix: Honoraria, Research Funding; Xencor: Research Funding; Sunesis: Honoraria. Daver:Sunesis: Consultancy; Alexion: Consultancy; Daiichi-Sankyo: Research Funding; BMS: Research Funding; ImmunoGen: Consultancy; Kiromic: Research Funding; Incyte: Research Funding; Pfizer: Consultancy; Incyte: Consultancy; ARIAD: Research Funding; Karyopharm: Consultancy; Pfizer: Research Funding; Karyopharm: Research Funding; Novartis: Consultancy; Sunesis: Research Funding; Novartis: Research Funding; Otsuka: Consultancy. Jain:Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; ADC Therapeutics: Research Funding; Infinity: Research Funding; Pfizer: Research Funding; Novimmune: Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees; BMS: Research Funding; Servier: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Research Funding; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Genentech: Research Funding; ADC Therapeutics: Honoraria, Membership on an entity's Board of Directors or advisory committees; Adaptive Biotechnologioes: Research Funding; Pharmacyclics: Research Funding; Incyte: Research Funding; Verastem: Research Funding; Seattle Genetics: Research Funding; Pharmacyclics: Honoraria, Membership on an entity's Board of Directors or advisory committees; Astra Zeneca: Research Funding; Astra Zeneca: Research Funding; Servier: Research Funding; Celgene: Research Funding; Seattle Genetics: Research Funding; Verastem: Honoraria, Membership on an entity's Board of Directors or advisory committees; Astra Zeneca: Honoraria, Membership on an entity's Board of Directors or advisory committees; Infinity: Research Funding; Adaptive Biotechnologies: Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: Research Funding; Cellectis: Research Funding; ADC Therapeutics: Research Funding; Abbvie: Honoraria, Membership on an entity's Board of Directors or advisory committees; Adaptive Biotechnologioes: Research Funding; Pharmacyclics: Research Funding; Cellectis: Research Funding; Verastem: Research Funding; Servier: Research Funding; Abbvie: Research Funding; Incyte: Research Funding; Genentech: Research Funding; Abbvie: Research Funding; BMS: Research Funding; Astra Zeneca: Honoraria, Membership on an entity's Board of Directors or advisory committees; Verastem: Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; ADC Therapeutics: Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees; Servier: Honoraria, Membership on an entity's Board of Directors or advisory committees; Novimmune: Honoraria, Membership on an entity's Board of Directors or advisory committees; Adaptive Biotechnologies: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Pharmacyclics: Honoraria, Membership on an entity's Board of Directors or advisory committees; Abbvie: Honoraria, Membership on an entity's Board of Directors or advisory committees. Maiti:Celgene Corporation: Other: Research funding to the institution. Martinez:PharmaMar: Employment. Siguero:PharmaMar: Employment. Al-Kali:Novartis: Research Funding.

Survival outcomes for older adults with acute lymphoblastic leukemia (ALL) are poor and optimal management is challenging due to higher-risk leukemia genetics, comorbidities, and lower tolerance to intensive therapy. A critical understanding of these factors guides the selection of frontline therapies and subsequent treatment strategies. In addition, there have been recent developments in minimal/measurable residual disease (MRD) testing and blinatumomab use in the context of MRD-positive disease after therapy. These NCCN Guidelines Insights discuss recent updates to the NCCN Guidelines for ALL regarding upfront therapy in older adults and MRD monitoring/testing in response to ALL treatment.