ALBERT

Description: Translating the genetic and epigenetic heterogeneity underlying human cancers into therapeutic strategies is an ongoing challenge. Large-scale sequencing efforts have uncovered a spectrum of mutations in many hematologic malignancies, including acute myeloid leukemia (AML), suggesting that combinations of agents will be required to treat these diseases effectively. Combinatorial approaches will also be critical for combating the emergence of genetically heterogeneous subclones, rescue signals in the microenvironment, and tumor-intrinsic feedback pathways that all contribute to disease relapse. To identify novel and effective drug combinations, we performed ex vivo sensitivity profiling of 122 primary patient samples from a variety of hematologic malignancies against a panel of 48 drug combinations. The combinations were designed as drug pairs that target nonoverlapping biological pathways and comprise drugs from different classes, preferably with Food and Drug Administration approval. A combination ratio (CR) was derived for each drug pair, and CRs were evaluated with respect to diagnostic categories as well as against genetic, cytogenetic, and cellular phenotypes of specimens from the two largest disease categories: AML and chronic lymphocytic leukemia (CLL). Nearly all tested combinations involving a BCL2 inhibitor showed additional benefit in patients with myeloid malignancies, whereas select combinations involving PI3K, CSF1R, or bromodomain inhibitors showed preferential benefit in lymphoid malignancies. Expanded analyses of patients with AML and CLL revealed specific patterns of ex vivo drug combination efficacy that were associated with select genetic, cytogenetic, and phenotypic disease subsets, warranting further evaluation. These findings highlight the heuristic value of an integrated functional genomic approach to the identification of novel treatment strategies for hematologic malignancies.

Description: Acute myeloid leukemia (AML) is the most common acute leukemia in adults, with approximately four new cases per 100,000 persons per year. Standard treatment for AML consists of induction chemotherapy with remission achieved in 50 to 75% of cases. Unfortunately, most patients will relapse and die from their disease, as 5-y survival is roughly 29%. Therefore, other treatment options are urgently needed. In recent years, immune-based therapies have led to unprecedented rates of survival among patients with some advanced cancers. Suppression of T cell function in the tumor microenvironment is commonly observed and may play a role in AML. We found that there is a significant association between T cell infiltration in the bone marrow microenvironment of newly diagnosed patients with AML and increased overall survival. Functional studies aimed at establishing the degree of T cell suppression in patients with AML revealed impaired T cell function in many patients. In most cases, T cell proliferation could be restored by blocking the immune checkpoint molecules PD-1, CTLA-4, or TIM3. Our data demonstrate that AML establishes an immune suppressive environment in the bone marrow, in part through T cell checkpoint function.

Description: Background: The identification of effective therapies based on targeted interventions for human cancers faces the challenges of genetic and epigenetic heterogeneity underlying the disease. Large-scale sequencing efforts have uncovered a spectrum of mutations in many hematologic malignancies, suggesting that combinations of agents will be required to treat these diseases effectively. Combinatorial approaches will also be critical for combating the emergence of genetically heterogeneous subclones, rescue signals in the microenvironment, and tumor-intrinsic feedback pathways that all contribute to disease relapse. Methods: We used a functional ex vivo screening assay to identify small-molecule targeted inhibitors and inhibitor combinations demonstrating selective efficacy across broad categories of leukemia. Primary mononuclear cells isolated from leukemia patients (n=588) were plated in the presence of a panel of graded concentrations of over 120 single-agent inhibitors or combinations spanning multiple drug classes. Leukemia specimens from 5 diagnosis subgroups included acute myeloid leukemia (AML; n=293), acute lymphoblastic leukemia (ALL; n=83), chronic lymphocytic leukemia (CLL; n=140), chronic myeloid leukemia (CML; n=26) and myeloproliferative neoplasms/myelodysplastic syndrome (MPN or MDS/MPN; n=46) patients. The combinations were designed as drug pairs that target non-overlapping biological pathways and comprise drugs from different classes, preferably with Food and Drug Administration approval. IC50 and AUC values were derived from probit-based regression for each response curve. Mutational status for FLT3-ITD and NPM1 were compiled from clinical labs or by capillary electrophoresis using a QiaXcel instrument. Disease status was obtained from clinical chart review. Single and combination drug treatment IC50 and AUC values were compared within groups by Friedman test, across groups by Kruskal-Wallis test, and with continuous variables by Spearman rank correlation. Results: Among 588 unique leukemia patients evaluated, we observed that the combination of venetoclax (a BCL2 inhibitor) with ibrutinib(a BTK inhibitor) showed enhanced benefit above that for either single agent in both myeloid and lymphoid malignancies, including AML, ALL, and CLL. Expanded analyses of combination sensitivity in AML patients showed no significant associations with age, gender, or ELN prognostic risk. Comparison of AML samples by disease treatment status indicated a slightly greater sensitivity in relapsed/refractory (n=42) versus newly diagnosed (n=115) AML samples by both AUC and IC50 (p=0.028 and 0.026, respectively). Among AML samples, FLT3-ITD and NPM1 mutation status was available for 204 and 188 patients, respectively. Venetoclax + ibrutinib was significantly more effective in patient samples harboring FLT3-ITD or NPM1 mutations by both AUC (p=0.0002 and p=0.0032, respectively) and IC50 (p=0.0002 and p=0.021, respectively). Furthermore, among 112 AML samples with RNAseq data available, sensitivity to the combination (AUC) was significantly correlated with gene expression for BCL2 and BTK (Spearman r: -0.48 and -0.21, respectively). Evaluation of the combination using an expanded 7x7 concentration matrix on AML cell lines revealed synergy for the majority of drug-pair concentrations by the Bliss independence model. Analysis to align additional clinical and genetic features for leukemia patient samples with drug sensitivities is in progress and results with be presented at the meeting. Conclusion: Both myeloid and lymphoid-derived primary leukemia cells show sensitivity to combined inhibition of BCL2 and BTK with the combination of venetoclax and ibrutinib, suggesting this drug pair may have broad therapeutic indications. Disclosures Tyner: Vivid Biosciences: Membership on an entity's Board of Directors or advisory committees; Takeda: Research Funding; Genentech: Research Funding; Gilead: Research Funding; Constellation: Research Funding; Janssen: Research Funding; AstraZeneca: Research Funding; Incyte: Research Funding; Array: Research Funding; Aptose: Research Funding. Danilov:TG Therapeutics: Consultancy; Takeda Oncology: Research Funding; Aptose Biosciences: Research Funding; Genentech: Consultancy, Research Funding; Astra Zeneca: Consultancy; Gilead Sciences: Consultancy, Research Funding; Bayer Oncology: Consultancy, Research Funding; Verastem: Consultancy, Research Funding. Druker:Aileron Therapeutics: Consultancy; Third Coast Therapeutics: Membership on an entity's Board of Directors or advisory committees; Aptose Therapeutics: Consultancy, Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Patient True Talk: Consultancy; Vivid Biosciences: Membership on an entity's Board of Directors or advisory committees; GRAIL: Consultancy, Membership on an entity's Board of Directors or advisory committees; ARIAD: Research Funding; Oregon Health & Science University: Patents & Royalties; Fred Hutchinson Cancer Research Center: Research Funding; Cepheid: Consultancy, Membership on an entity's Board of Directors or advisory committees; Millipore: Patents & Royalties; Leukemia & Lymphoma Society: Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead Sciences: Consultancy, Membership on an entity's Board of Directors or advisory committees; McGraw Hill: Patents & Royalties; Henry Stewart Talks: Patents & Royalties; Novartis Pharmaceuticals: Research Funding; Monojul: Consultancy; ALLCRON: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy; Beta Cat: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees; Bristol-Meyers Squibb: Research Funding; MolecularMD: Consultancy, Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Blueprint Medicines: Consultancy, Equity Ownership, Membership on an entity's Board of Directors or advisory committees.

Description: To identify new therapeutic targets in acute myeloid leukemia (AML), we performed small-molecule and small-interfering RNA (siRNA) screens of primary AML patient samples. In 23% of samples, we found sensitivity to inhibition of colony-stimulating factor 1 (CSF1) receptor (CSF1R), a receptor tyrosine kinase responsible for survival, proliferation, and differentiation of myeloid-lineage cells. Sensitivity to CSF1R inhibitor GW-2580 was found preferentially in de novo and favorable-risk patients, and resistance to GW-2580 was associated with reduced overall survival. Using flow cytometry, we discovered that CSF1R is not expressed on the majority of leukemic blasts but instead on a subpopulation of supportive cells. Comparison of CSF1R-expressing cells in AML vs healthy donors by mass cytometry revealed expression of unique cell-surface markers. The quantity of CSF1R-expressing cells correlated with GW-2580 sensitivity. Exposure of primary AML patient samples to a panel of recombinant cytokines revealed that CSF1R inhibitor sensitivity correlated with a growth response to CSF1R ligand, CSF1, and other cytokines, including hepatocyte growth factor (HGF). The addition of CSF1 increased the secretion of HGF and other cytokines in conditioned media from AML patient samples, whereas adding GW-2580 reduced their secretion. In untreated cells, HGF levels correlated significantly with GW-2580 sensitivity. Finally, recombinant HGF and HS-5–conditioned media rescued cell viability after GW-2580 treatment in AML patient samples. Our results suggest that CSF1R-expressing cells support the bulk leukemia population through the secretion of HGF and other cytokines. This study identifies CSF1R as a novel therapeutic target of AML and provides a mechanism of paracrine cytokine/growth factor signaling in this disease.

Description: Background : Various pro-inflammatory and stress-related stimuli activate p38 mitogen-activated protein kinase (p38MAPK), triggering cascades of cell proliferation, differentiation, and apoptosis signaling. We have previously found that inflammatory cytokines promote growth and survival in primary cells from acute myeloid leukemia (AML) patients. The downstream mediator of inflammatory pathways is p38MAPK, and blocking this regulator with kinase inhibitors abrogates inflammation signaling in AML cells. Methods : We used a functional ex vivo screening assay to identify small-molecule targeted inhibitors and inhibitor combinations demonstrating selective efficacy across broad categories of leukemia. Primary mononuclear cells isolated from leukemia patients (n=408) were plated in the presence of the p38MAPK inhibitor doramapimod or combinations of doramapimod with a second targeted agent that inhibits or effects a non-overlapping biological pathway. A 7-point concentration series was evaluated for both single agent inhibitors and combinations. Leukemia specimens from 408 unique patients were classified into 5 diagnosis subgroups including acute myeloid leukemia (AML; n=206), acute lymphoblastic leukemia (ALL; n=42), chronic lymphocytic leukemia (CLL; n=115), chronic myeloid leukemia (CML; n=16) and myeloproliferative neoplasms/myelodysplastic syndrome (MPN or MDS/MPN; n=29). IC50 and AUC values were derived from probit-based regression for each response curve. Mutational status for FLT3-ITD and NPM1 were compiled from clinical labs or by capillary electrophoresis using a QiaXcel instrument. Disease status was obtained from clinical chart review. For a subset of AML samples, RNAseq analysis was obtained in parallel to drug sensitivity testing. Single and combination drug treatment IC50 and AUC values were compared within groups by Friedman test, across groups by Kruskal-Wallis test, and with continuous variables by Spearman rank correlation. Results : Among diagnostic subgroups tested, AML specimens showed the lowest median IC50 for doramapimod (1.71 uM), with 75 of 206 samples tested (36%) exhibiting IC50 values 〈 0.5 uM. In contrast, CLL specimens were significantly less sensitive (median IC50: 4.73 uM), with 27 of 115 samples tested (23%) showing IC50〈 0.5 uM. For ALL, CML, and MDS/MPN subgroups, median IC50 values were 10, 3.19, and 6.78 uM, respectively; this translated to 17% of ALL, 19% of CML, and 38% of MDS/MPN samples with IC50〈 0.5 uM. Doramapimod was also tested in combination with inhibitors of histone deacetylase (panobinostat), cyclin-dependent kinases 4/6 (CDK4/6; palbociclib), bromodomain and extra-terminal (BET) domain (JQ1), and BCL2 (venetoclax). Doramapimod combinations with panobinostat or JQ1 did not show enhanced efficacy compared to either single agent. However, combining doramapimod with palbociclib or venetoclax resulted in significantly enhanced efficacy compared to each single agent (median IC50: 0.014 and 0.075 uM, respectively; p

Description: Background: In patients with acute lymphoblastic leukemia (ALL), patient outcomes vary considerably by patient age group, specific genetic subtypes, and treatment regimen. Large-scale sequencing efforts have uncovered a spectrum of mutations and gene fusions in ALL, suggesting that combinations of agents will be required to treat these diseases effectively. Previous preclinical studies have shown efficacy of the BCL2 inhibitor venetoclax alone or in combination in ALL cells (Chonghaile et al., Can Disc 2014; Leonard et al, STM 2018), and the multi-kinase inhibitor ibrutinib (approved for patients with chonic lymphoblastic leukemia (CLL)) has also shown potent activity in subsets of ALL (Kim et al., Blood 2017). However, the combination of ibrutinib and venetoclax has not been evaluated to date in patients with ALL. Methods: We used a functional ex vivo screening assay to evaluate the potential efficacy of the combination of ibrutinib and venetoclax (IBR+VEN) across a large cohort (n=808) of patient specimens representing a broad range of hematologic malignancies. Primary mononuclear cells isolated from leukemia patients were plated in the presence of graded concentrations of venetoclax, ibrutinib, or the combination of both FDA-approved drugs. IC50 and AUC values were derived from probit-based regression for each response curve. A panel of clinical labs, treatment information, and genetic features for tested ALL patient specimens was collated from chart review. Single and combination drug treatment sensitivity were compared within groups by Friedman test, across groups by Mann-Whitney test, and with continuous variables by Spearman rank correlation. Results: Consistent with clinical data and previous literature, IBR+VEN was highly effective in CLL specimens ex vivo (median IC50=0.015 µM). Intriguingly, among specimens from 100 unique ALL patients, we also observed that IBR+VEN demonstrated significantly enhanced efficacy by AUC and IC50 compared to either single agent (p

Description: Introduction: Translating the genetic and epigenetic heterogeneity underlying human cancers into therapeutic strategies represents an ongoing challenge. Large-scale sequencing efforts have identified that many hematologic malignancies, such as acute myeloid leukemia (AML), are driven by a spectrum of mutations and may require combinations of targeted agents to be treated effectively. In addition, the emergence of genetically heterogeneous subclones leading to relapse, rescue signals in the microenvironment, and tumor-intrinsic feedback pathways further necessitate combinatorial therapies. To identify combinations of targeted drugs for AML and other hematologic malignancies, we performed ex vivo profiling of pairs of small-molecule inhibitors for sensitivity against primary patient samples. Methods: Freshly isolated primary mononuclear cells from patients (n=122) with various hematologic malignancies (AML n=58, CLL n=42, ALL n=12, and MPN or MDS/MPN n=10) were cultured in the presence of a panel of 48 drug combinations in equimolar dose series encompassing different classes of compounds, including kinase inhibitors, bromodomain inhibitors, BH3 mimetics, and histone deacetylase inhibitors. For comparison, cells were also tested against graded concentrations of each inhibitor alone, and sensitivity was assessed by MTS-based viability assay. IC50 and AUC values were derived using a probit regression model. Efficacy of each combination relative to its single agents was calculated as a Combination Ratio (CR) value, defined as the combination IC50 or AUC divided by the lowest single agent IC50 or AUC value. A CR value 〈 1 indicates the combination is more effective relative to the single agent. Associated clinical characteristics were obtained where possible. For the 2 largest diagnostic groups, AML and CLL, expanded panels of clinical, prognostic, mutational, cytogenetic, and surface antigen data were compiled for comparisons according to CR values for each combination. Results: Unsupervised hierarchical clustering of CR values revealed several distinct clusters (Figure 1). Myeloid leukemia patient samples were enriched within a cluster of sensitivity to combinations pairing the Bcl-2 inhibitor venetoclax with select tyrosine kinase inhibitors (dasatinib, doramapimod, sorafenib, or idelalisib). A subset of samples within this cluster showed sensitivity to combinations involving the MEK inhibitor trametinib and a second kinase inhibitor (idelalisib, palbociclib, or quizartinib). In contrast, a discrete subcluster of predominantly lymphoid leukemia patients showed sensitivity to combinations of the histone deacetylase inhibitor panobinostat in tandem with either the JAK inhibitor ruxolitinib or the multi-kinase inhibitor sorafenib. Importantly, apart from venetoclax which as a single agent demonstrated potent and selective efficacy in CLL patient samples, the single agent efficacies do not align selectively to a combination efficacy-derived cluster (Figure 1). Comparison of CR values within each of the 4 diagnostic groups revealed partial overlap in statistically significant effective combinations, while also highlighting unique sensitivities by group, such as idelalisib-quizartinib for AML and ibrutinib-quizartinib for CLL. Further relevant clinical and genetic features were compared within each of the 2 largest groups, AML and CLL. Among AML samples, patients harboring mutations in NPM1 or DNMT3A demonstrated significant sensitivity to combinations of JQ1 and sorafenib (median CR: 0.357) or JQ1 and palbociclib (median CR: 0.119), respectively. AML patients featuring surface expression of CD11b (Integrin aM) or CD58 (LFA-3) were sensitive to combinations of venetoclax and JQ1 or venetoclax and doramapimod, respectively. Among CLL samples, patients harboring deletion of 13q showed significant sensitivity to combinations of palbociclib with either venetoclax or trametinib (median CR: 0.267 and 0.116, respectively). Conclusions: The data reveal multiple specific patterns of ex vivo drug combination efficacy beyond that of either single agent, which are associated with select, actionable diagnostic and genetic subsets, warranting their evaluation in the clinic. These findings highlight the heuristic value of an integrated approach for identifying novel treatment strategies for improved disease control and patient outcomes. Figure 1 Figure 1. Disclosures Druker: Agios: Honoraria; Ambit BioSciences: Consultancy; ARIAD: Patents & Royalties, Research Funding; Array: Patents & Royalties; AstraZeneca: Consultancy; Blueprint Medicines: Consultancy, Equity Ownership, Other: travel, accommodations, expenses ; BMS: Research Funding; CTI: Equity Ownership; Curis: Patents & Royalties; Cylene: Consultancy, Equity Ownership; D3 Oncology Solutions: Consultancy; Gilead Sciences: Consultancy, Other: travel, accommodations, expenses ; Lorus: Consultancy, Equity Ownership; MolecularMD: Consultancy, Equity Ownership, Patents & Royalties; Novartis: Research Funding; Oncotide Pharmaceuticals: Research Funding; Pfizer: Patents & Royalties; Roche: Consultancy. Tyner:Constellation Pharmaceuticals: Research Funding; Agios Pharmaceuticals: Research Funding; Takeda Pharmaceuticals: Research Funding; Inctye: Research Funding; Genentech: Research Funding; Aptose Biosciences: Research Funding; Seattle Genetics: Research Funding; Array Biopharma: Research Funding; AstraZeneca: Research Funding; Leap Oncology: Consultancy; Janssen Research & Development: Research Funding.

Description: Introduction: It has long been recognized that expert care can improve outcomes for CLL patients (pts). Moreover, CLL treatment has rapidly changed over the past several years, making it challenging for healthcare providers (HCP) to keep pace with new therapies. Many pts do not have access to CLL experts due to geography, insurance, or cost. Telemedicine can provide HIPAA-compliant access to experts. The nonprofit CLL Society, working with 10 CLL experts and using a platform from an online 2nd opinion service (InfiniteMD), coordinated 105 telemedicine consults in 2017-19 as part of a free Expert Access Program (EAP). Here we report the impact of this service on a nationwide underserved CLL population. Methods: The EAP application was available online at CLLSociety.org with links on CLL forums and in weekly alerts sent to 〉5000 pts. It was promoted at CLL Society patient educational forums and 28 support groups. To qualify for EAP, participants needed to be US residents who had a CLL diagnosis but weren't seeing an expert physician (defined as a nationally recognized CLL research physician who primarily cares for CLL pts). Pts meeting inclusion criteria were asked to complete a pre-consult survey and had their electronic records synopsized for review by the consulting expert. Pts then participated in a 30-minute online HIPAA-compliant video consult with the CLL expert. Following the consult, pts received a summary to share with their local HCP and were asked to complete a (post-) survey. Data were analyzed using descriptive statistics and Clopper-Pearson confidence intervals. Results: The pre-consult survey was filled out by 116 pts (age range [median] = 28 to 88 [62], 53% male), of whom 105 had the EAP consult and 84 finished the post- survey. Several post-survey questions asked pts if they had a greater understanding of their CLL after the online consult compared to before. EAP had the following impact on the 84 pts completing the post-survey: 64% became more confident in their current HCP, 82% had a better understanding of their CLL diagnosis and treatment/management plan, 85% had improved confidence in this plan, and 86% were more confident in understanding their prognostic test results. Only 25% of these 84 pts did not plan to make any changes regarding their disease. The breakdown of intended future actions (pts could select 〉1 answer) according to the post- survey was as follows: 55% would consider a clinical trial42% planned to do more research about CLL35% planned to have more tests done24% planned to see a new doctor20% planned to pursue additional genetic testing8% planned to pursue a different treatment4% planned to delay treatment Additionally, 92% of these pts learned something new from their EAP physician, 42% learned about a prognostic test they previously had not undergone, and 31% believed their diagnosis and/or CLL stage should be re-evaluated. Only 2% of the 84 pts who completed the post-survey did not find the online consult easy, due to hearing trouble or video issues. In fact, 95% affirmed that the convenience of the online platform was important in their decision to participate in EAP. All but 6% had confidence in and trusted the expert and 83% felt a greater peace of mind after their encounter. Every patient but 1 said they would recommend EAP. Limitations: Twenty percent of the 105 pts who had a consult did not complete the post-survey, raising the possibility of reporting bias if those who failed to follow-up did so because of a negative experience. Differences in the exact wording between the 2 surveys prevented a pre-vs. post-statistical analysis. However, post-survey questions asking about relative confidence or understanding (using the words "better" or "more") elicited information on the impact of EAP. Conclusions: Access to CLL experts through EAP provides useful medical information. While confidence in a patient's current HCP improved because of the consult, 75% (95% CI: 64% - 84%) planned to make some type of change regarding their CLL management. Thus, an online consult with an expert may benefit pts by both increasing their confidence in their local HCP and in their knowledge of CLL, while motivating them to act. More research is needed to study longer term effects of the EAP. Disclosures Koffman: abbvie: Equity Ownership; astra zeneca: Equity Ownership, Honoraria; Beigene: Equity Ownership; Bristol-Meyers-Squibb: Equity Ownership, Honoraria; Gilead Sciences: Equity Ownership; JNJ: Equity Ownership, Honoraria; MEI: Equity Ownership; Miragen Therapeutics: Equity Ownership; Novartis: Membership on an entity's Board of Directors or advisory committees; Portola Pharm: Equity Ownership; Sunesis Pharm: Equity Ownership; TG Therapeutics: Equity Ownership; Verastem Oncology: Equity Ownership, Honoraria. Pagel:AstraZeneca: Consultancy; Gilead Sciences: Consultancy; Pharmacyclics: Consultancy. Byrd:Gilead: Other: Travel Expenses, Research Funding, Speakers Bureau; Janssen: Consultancy, Other: Travel Expenses, Research Funding, Speakers Bureau; TG Therapeutics: Other: Travel Expenses, Research Funding, Speakers Bureau; TG Therapeutics: Other: Travel Expenses, Research Funding, Speakers Bureau; Novartis: Other: Travel Expenses, Speakers Bureau; Genentech: Research Funding; Ohio State University: Patents & Royalties: OSU-2S; Acerta: Research Funding; Acerta: Research Funding; Ohio State University: Patents & Royalties: OSU-2S; BeiGene: Research Funding; Pharmacyclics LLC, an AbbVie Company: Other: Travel Expenses, Research Funding, Speakers Bureau; BeiGene: Research Funding; Genentech: Research Funding; Pharmacyclics LLC, an AbbVie Company: Other: Travel Expenses, Research Funding, Speakers Bureau; Janssen: Consultancy, Other: Travel Expenses, Research Funding, Speakers Bureau; Novartis: Other: Travel Expenses, Speakers Bureau; Gilead: Other: Travel Expenses, Research Funding, Speakers Bureau. Skarbnik:Abbvie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Verastem Oncology: Honoraria, Research Funding, Speakers Bureau; Kite Pharma: Honoraria, Speakers Bureau; Gilead Sciences: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Consultancy, Honoraria, Speakers Bureau; Acerta: Research Funding; Seattle Genetics: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Genentech: Honoraria, Speakers Bureau; CLL Society: Consultancy, Membership on an entity's Board of Directors or advisory committees; Jazz Pharmaceuticals: Speakers Bureau; Novartis: Speakers Bureau; Pharmacyclics: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Consultancy, Honoraria, Research Funding, Speakers Bureau. Davids:AbbVie, Astra-Zeneca, Genentech, Janssen, MEI, Pharmacyclics, Syros Pharmaceuticals, Verastem: Consultancy; Acerta Pharma, Ascentage Pharma, Genentech, MEI pharma, Pharmacyclics, Surface Oncology, TG Therapeutics, Verastem: Research Funding; Research to Practice: Honoraria; AbbVie, Acerta Pharma, Adaptive, Biotechnologies, Astra-Zeneca, Genentech, Gilead Sciences, Janssen, Pharmacyclics, TG therapeutics: Membership on an entity's Board of Directors or advisory committees. Danilov:Bristol-Meyers Squibb: Research Funding; Aptose Biosciences: Research Funding; Genentech: Consultancy, Research Funding; AstraZeneca: Consultancy, Research Funding; Gilead Sciences: Consultancy, Research Funding; Seattle Genetics: Consultancy; MEI: Research Funding; Bayer Oncology: Consultancy, Research Funding; Curis: Consultancy; TG Therapeutics: Consultancy; Takeda Oncology: Research Funding; Celgene: Consultancy; Janssen: Consultancy; Pharmacyclics: Consultancy; Verastem Oncology: Consultancy, Other: Travel Reimbursement , Research Funding; Abbvie: Consultancy.

Description: Background: The efficacy of the BCL2 inhibitor venetoclax combined with azacytidine (Ven+Aza), recently approved for elderly patients unfit for standard chemotherapy, highlights the promise of combination therapies for acute myeloid leukemia (AML). However, overall and progression-free survival remain at ~30-40% after 1 year of therapy, warranting exploration of new venetoclax combinations and elucidation of mechanisms and biomarkers of response and resistance. Methods: We examined a series of venetoclax combinations using a functional genomics approach applied directly to 〉350 primary AML patient specimens. Primary patient mononuclear cells were plated ex vivo with a panel of 10 venetoclax combinations and the represented single agents. Whole exome and RNA-sequencing were obtained from the same patient samples. Levels of plasma cytokine levels were obtained from the patient samples where possible. Clinical, genetic, and disease status information were collated, and ex vivo combination sensitivities were compared to matched single agent data by Friedman test, across groups by Kruskal-Wallis test, and with continuous variables by Spearman rank correlation. Results: Consistent with clinical findings, Ven+Aza showed significantly enhanced efficacy in AML samples ex vivo (median IC50 = 0.100 uM), with evidence of enhanced efficacy compared to each single agent (AUC CR = 0.795). Using this as a benchmark, we found 9 venetoclax combinations (venetoclax paired with ruxolitinib, palbociclib, ARRY-382, doramapimod, trametinib, sorafenib, dasatinib, JQ1, or panobinostat) which exceeded both the ex vivo activity and enhanced efficacy observed with Ven+Aza (Fig. 1A). We evaluated associations of clinical and genetic data with combination sensitivity, using the Rux+Ven combination as a lead example. Importantly, Rux+Ven demonstrated similarly enhanced ex vivo efficacy in newly diagnosed and relapsed/refractory AML patient specimens. At the genetic level, Rux+Ven sensitivity included not only specimens harboring the highly frequent FLT3-ITD and NPM1 mutations, but also those with TP53 mutations, which carries a very poor disease prognosis clinically and associated with venetoclax resistance. Certain cytogenetic features correlated with greater sensitivity to Rux+Ven (e.g. t(9;11) - MLL-rearrangement) or decreased sensitivity (e.g. t(15;17) - PML-RARA or monosomy 5/del 5q) (Fig. 1B). To define gene expression-based differences associated with ex vivo sensitivity to venetoclax combinations, we assessed expression level differences between the 25% most sensitive and 25% least sensitive patient samples. For the Rux+Ven combination, this yielded ~1500 differentially expressed genes (FDR-adjusted p-value 〈 0.05) which showed enrichment of several Reactome pathways including PD-1 and IL-27 signaling, suggestive of a role for cytokine and immune signals. Concordantly, we found levels of certain cytokines correlated with Rux+Ven sensitivity or resistance. Similarly analyses of clinical and genetic biomarkers of sensitivity and resistance for the other venetoclax combinations tested is in progress and will be presented. Conclusion: We have identified drug combinations with ex vivo activity that exceeds that of Ven+Aza and have identified clinical, mutational, and expression-based biomarker patterns associated with sensitivity and resistance to these combinations. Importantly, an understanding of the biology underlying the efficacy of each specific combination will offer an opportunity to fine-tune their clinical application towards the AML subsets most likely to benefit from each combination strategy and may also propel testing of these combinations in other malignancies. Figure 1 . Sensitivity of Venetoclax-containing combinations on AML patient samples. A. Summary of all venetoclax combinations tested for efficacy (AUC, horizontal axis) and synergy (CR vertical axis). CR denotes Combination Ratio and is defined as the AUC of the combination/AUC of the most effective single agent in the combination. Median AUC CR and 95% CI are shown. Red indicates combinations with better efficacy and synergy than venetoclax + azacytidine B. Summary of clinical and genetic features of AML that correlate with Rux+Ven sensitivity (blue) or resistance (orange). **** denotes p

Description: Introduction: Outcomes in CLL are highly variable and influenced by both biologic and clinical factors. The Cumulative Illness Rating Scale (CIRS) is frequently used to assess comorbidities in CLL. Our group has demonstrated that CIRS correlates with survival in patients treated with either CIT or ibrutinib. Yet, CIRS has not become part of common clinical practice due to complexities in scoring since 14 systems need to be evaluated. Furthermore, the relative contribution of individual comorbidities to patient outcomes is unknown. Here we report the impact of specific comorbidities in a large cohort of CLL patients and propose a simplified CLL-comorbidity index (CLL-CI). Methods: We conducted a retrospective analysis of patients with CLL treated with either CIT or kinase inhibitors at 10 US academic medical centers between 2000-2018. CIRS score was calculated as in Salvi et al, 2008. Patients were randomly divided into a training-set (n=381) and validation-set (n=189). Random survival forests (RSF) were constructed on the training-set to select variables for Cox regression models. Discrimination of models was tested in the validation-set. CIRS score in each organ system, relapse/refractory (R/R) disease, treatment type, age, and del(17p) were included as features for RSF modeling of event-free survival (EFS), defined as time from treatment to death, disease progression or next therapy. For each RSF, features were scored and ranked according to variable importance (VI; the decrease in prediction accuracy when the specific variable is randomly permuted) and minimal depth (MD; the minimum distance between the root node of a tree and the first node that splits on the specific variable). After 200 RSF's, VI and MD ranks were averaged. Organ system variables whose average rank for both predictive measures was ≤10 were chosen for Cox regression modeling of EFS and OS. Three sets of Cox models were fit on the training data and applied to the validation-set to compute c-statistics depicting each model's ability to predict EFS. Cox models assessed the addition of either CIRS or CLL-CI to known prognostic factors. Results: The data set contained 614 patients; 570 (93%) with complete data were included in our analysis. Median age was 67 years (range 30-91). Median CIRS was 7 (range, 0-29) with CIRS≥7 in 302 patients (53%). Median follow up was 31 months. Del(17p) and/or TP53 mutation was present in 113 patients (20%) and 299 (52%) were assessed in the R/R setting. Ibrutinib was the most common treatment (n=338, 59%), followed by fludarabine (n=163) and bendamustine (n=116). In the training-set, four organ system variables ("musculoskeletal", "renal", "endocrine" and "upper GI"), were selected based on RFS average predictive measure ranks and summed to derive the CLL-CI score. Median CLL-CI was 2 (range, 0-11) in the training cohort with a value of 3 identified as the optimal cut-point for association with EFS; 236 (41%) had a high CLL-CI score (≥3). Cox models that included either CLL-CI or CIRS (alongside age, disease status, type of treatment, and del(17p)/TP53 mutation) yielded c-statistics of 0.68 (95% CI: 0.65-0.69) and 0.68 (95% CI: 0.65-0.70), respectively. These discrimination estimates were modestly superior to the model without a comorbidity variable (c-statistic, 0.64). In the complete data set, R/R disease and age were associated with decreased EFS (HR=2.14, p