Functional Precision Medicine Research Articles

1471P 3D patient-derived gastric cancer organoids as a tool for functional precision medicine for gastric cancer patients

1471P 3D patient-derived gastric cancer organoids as a tool for functional precision medicine for gastric cancer patients

Abstract 6124: Translation of zebrafish tumor-derived xenograft-models for improved diagnosis and treatment planning in urinary bladder cancer patients

Abstract Precision medicine in oncology aims to identify the most effective treatment for any given patient based on individualized analyses of patient material. Currently, precision medicine relies on sequencing of DNA or RNA to identify patient tumor-specific mutational profiles that may be coupled to drug response. These techniques, however, fail to reveal actionable mutations in approximately 85% of the cancer patients, and have not been established at all for many commonly used drugs including cisplatin-based treatments used in urinary bladder cancer. While mouse-PDX models can determine drug response rates with high accuracy in most patients and for most drugs, such techniques are too slow and expensive to be relevant for first line treatment planning. Urinary bladder cancer patients are often treated with cisplatin-containing combination therapy, with the hope of down-staging tumors before surgery. 60%, however, do not respond or even progress on this treatment, and these patients would benefit from immediate surgery upon diagnosis. To help identify non-responding patients, we show here that patient-derived tumor xenograft models can be established in zebrafish larvae (ZTX models) and that the resulting tumors exhibit differential responses to the two main cisplatin-containing treatments GC and MVAC. Preliminary results from the first 19 patients are presented. Two tumor biopsies were destroyed during transport and two did not allow isolation of sufficient viable cells for implantation. From the remaining 15 samples an average of 2,6 million cells with average viability of 53% were isolated and used to implant at least 60 2-days old larvae. All 15 samples implanted in the larvae and survived and/or grew exhibiting varying degrees of metastatic dissemination (average between 2 and 13 metastasized cells per embryo and model) within only three days from implantation. Four ZTX models exhibited different responses to GC and MVAC demonstrating that these treatments are not equally effective in all patients. Non-response in ZTX models was associated with tumors having re-appeared in the bladder upon radical cystectomy in all patients undergoing surgery prior to Dec. 5th 2019 (n=3). GC inhibited metastasis in all models (average 69% inhibition), whereas MVAC inhibited metastasis in 40% of the models (average 36% inhibition). In conclusion: The ZTX urinary bladder cancer platform presented here overcome limitations associated with long assay time and high cost of other functional models within precision medicine as well as the low hit-rate of actionable mutations associated with genomic techniques. ZTX models will therefore likely become a powerful method for functional precision medicine within oncology, in the near future. Citation Format: Zaheer Ali, Anna Nilsson, Malin Vildevall, Larissa Rizzo, Ylva Huge, Amir Sherif, Anna Fahlgren, Lasse DE Jensen. Translation of zebrafish tumor-derived xenograft-models for improved diagnosis and treatment planning in urinary bladder cancer patients [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 6124.

Abstract 5255: The SAGE Direct TestTM: A reliable way of functional profiling to predict the most effective treatment for cancer patients

Abstract Cancer is a genetic disease with increasing heterogeneity during disease progression. However, despite the widespread use of genomic testing, a recent publication estimated that only 5% of cancer patients in the US benefit from genome-driven targeted therapies, largely because “actionable mutations” are rare.[1] Thus, SageMedic has developed the SAGE Direct Test™, leading the next generation of functional precision medicine to accurately predict the most effective treatment for virtually all cancer patients without limitations of genomic sequencing or having to identify a specific pathway. Our SAGE Direct Test™ consists of four critical steps, i.e., tissue processing, creation of 3D microtumors, live/dead cell imaging, and metabolic profiling. Using our proprietary technology, we can create hundreds of 3D microtumors from a core needle biopsy sample that recapitulate the in vivo tumor heterogeneity and microenvironment of the tumor biopsy. After these microtumors have been treated with a panel of drugs, we quantify the number of live and dead cells in those microtumors using our proprietary technology and scalable automatic stage confocal imaging (Molecular Devices). The advantage of our SAGE Direct Platform™ is the ability to multiplex our image-based results with the metabolic profile of our 3D microtumors, which cross validates our image-based readout. Our SAGE Direct Test™ has been optimized with ATCC cell lines and further validated with patient-derived tumor cells from lung, ovarian, and colon cancer tumor samples. Validation of high-quality confocal imaging samples followed by quantitative metabolic analysis suggests accurate quantification of viable cells, as reflected in a positive correlation between imaging quantitation and metabolic analysis (correlation coefficient r=0.84, p<0.01). In summary, SageMedic has developed the SAGE Direct Test™, a simple, highly sensitive, robust, and straightforward functional profiling assay with significant clinical relevance, as it can model the natural physiological conditions of tumors. [1] Marquart et al. Estimation of the Percentage of US Patients With Cancer Who Benefit From Genome-Driven Oncology. JAMA Oncology 2018 Aug 1;4(8):1093-1098 Citation Format: Dhruva Mishra, Jennifer Moy, Chris Apfel. The SAGE Direct TestTM: A reliable way of functional profiling to predict the most effective treatment for cancer patients [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 5255.

Prioritizing targeted therapies in an evidence-based manner, integrating biological context and functional precision medicine.

e14065 Background: It is becoming increasingly common for cancer patients to undergo molecular profiling of their tumors in order to see whether there are any actionable DNA, gene expression, or protein expression signatures. For example, individuals with ER+ or HER2+ breast cancer or KRAS wild type (non-mutated) colorectal cancer are prescribed specific targeted therapies. When an individual’s molecular alterations do not match any currently-approved recommendations for their tumor type, their clinician may consider prescribing a therapy approved in a different tumor type. Unfortunately, tumors often eventually become resistant to the therapies they are exposed to, leading to a narrowing of options after each therapy line. Methods: We previously developed CDGnet, an evidence-based approach and web-based tool for prioritizing targeted therapies based on tumor molecular profiles based on known pathways which provide biological context. CDGnet considers approved therapies with biomarkers among the alterations for the individual’s tumor type and other tumor types as the first and second evidence level categories respectively. These are followed by therapies that target or have as biomarkers genes or proteins downstream of altered oncogenes, considering curated pathways for the individual’s tumor type and other tumor types as the third and fourth evidence level categories respectively. We are currently expanding CDGnet in order to include data from high-throughput screening (HTS) experiments of NCI oncologic drugs performed on patient-derived organoids. The concept of “functional precision medicine” consists of using functional drug efficacy determination directly on individual patients, in this case by considering drugs with low half maximal effective concentrations (EC50) which are tested on tissues derived from the actual patients. Results: We will present extensions to CDGnet that allow users to upload both the molecular profiles and the HTS data to see whether any drugs are predicted by both approaches or whether specific combinations appear promising for further testing. Preliminary results on a set of glioblastoma samples will be presented. Conclusions: We hope that extending CDGnet to also include HTS data will eventually allow a truly multi-factorial personalized oncology approach, whereby both molecular alterations at the DNA, RNA, and protein levels and patient-derived organoids will be considered in deciding on treatment plans for individuals.

A functional precision medicine 3D microtumor platform to identify and personalize novel indications.

e15588 Background: We have previously validated our 3D microtumor platform that captures the tumor heterogeneity of a patient's primary tumor biopsy using a patient-derived xenograft model (Nikolov et al. ASCO 2019, e17076). Here we describe its utility to identify FDA approved therapies that may be effective for tumors previously not considered. Methods: A fresh tumor sample of a liver metastasis of a 45-year-old colorectal cancer patient was shipped overnight and processed to create hundreds of live 3D microtumors. These microtumors were treated with a panel of 12 commonly used drugs including chemotherapies and targeted therapies. Treatment effects were quantified and validated on fresh and cryopreserved/thawed samples using our metabolic and proprietary multiplexed fluorescent staining technologies to quantify the ratio of live and dead cells in those microtumors. Results: None of the conventional treatments in the 12-panel drug test suggested any efficacy as determined by the log of efficacy concentrations (in µmol/l): Oxaliplatin 2.59, 5-FU 3.00 (upper cut-off value), paclitaxel 1.72, topotecan 3.00, irinotecan (SN-38) 2.33, gemcitabine 2.44, and bevacizumab 3.00. The microtumors also appeared resistant to several targeted therapies that are not commonly given, ranging from 1.85 to 2.44. However, abemaciclib had an efficacy of 0.49, which was confirmed on thawed samples with all drug efficacy concentrations again suggesting resistance, except for abemaciclib at 0.67. Conclusions: Our 3D microtumor platform may be a useful tool a) to identify rescue treatment options for metastatic patients that have multi-resistant tumors and b) to identify novel indications to personalize FDA-approved cytotoxic or targeted therapies as a companion diagnostic.

Breeze: an integrated quality control and data analysis application for high-throughput drug screening.

SummaryHigh-throughput screening (HTS) enables systematic testing of thousands of chemical compounds for potential use as investigational and therapeutic agents. HTS experiments are often conducted in multi-well plates that inherently bear technical and experimental sources of error. Thus, HTS data processing requires the use of robust quality control procedures before analysis and interpretation. Here, we have implemented an open-source analysis application, Breeze, an integrated quality control and data analysis application for HTS data. Furthermore, Breeze enables a reliable way to identify individual drug sensitivity and resistance patterns in cell lines or patient-derived samples for functional precision medicine applications. The Breeze application provides a complete solution for data quality assessment, dose–response curve fitting and quantification of the drug responses along with interactive visualization of the results.Availability and implementationThe Breeze application with video tutorial and technical documentation is accessible at https://breeze.fimm.fi; the R source code is publicly available at https://github.com/potdarswapnil/Breeze under GNU General Public License v3.0.Contact swapnil.potdar@helsinki.fi Supplementary information Supplementary data are available at Bioinformatics online.

Feasibility study of using high-throughput drug sensitivity testing to target recurrent glioblastoma stem cells for individualized treatment

BackgroundDespite the well described heterogeneity in glioblastoma (GBM), treatment is standardized, and clinical trials investigate treatment effects at population level. Genomics-driven oncology for stratified treatments allow clinical decision making in only a small minority of screened patients. Addressing tumor heterogeneity, we aimed to establish a clinical translational protocol in recurrent GBM (recGBM) utilizing autologous glioblastoma stem cell (GSC) cultures and automated high-throughput drug sensitivity and resistance testing (DSRT) for individualized treatment within the time available for clinical application.ResultsFrom ten patients undergoing surgery for recGBM, we established individual cell cultures and characterized the GSCs by functional assays. 7/10 GSC cultures could be serially expanded. The individual GSCs displayed intertumoral differences in their proliferative capacity, expression of stem cell markers and variation in their in vitro and in vivo morphology. We defined a time frame of 10 weeks from surgery to complete the entire pre-clinical work-up; establish individualized GSC cultures, evaluate drug sensitivity patterns of 525 anticancer drugs, and identify options for individualized treatment. Within the time frame for clinical translation 5/7 cultures reached sufficient cell yield for complete drug screening. The DSRT revealed significant intertumoral heterogeneity to anticancer drugs (p < 0.0001). Using curated reference databases of drug sensitivity in GBM and healthy bone marrow cells, we identified individualized treatment options in all patients. Individualized treatment options could be selected from FDA-approved drugs from a variety of different drug classes in all cases.ConclusionsIn recGBM, GSC cultures could successfully be established in the majority of patients. The individual cultures displayed intertumoral heterogeneity in their in vitro and in vivo behavior. Within a time frame for clinical application, we could perform DSRT in 50% of recGBM patients. The DSRT revealed a remarkable intertumoral heterogeneity in sensitivity to anticancer drugs in recGBM that could allow tailored therapeutic options for functional precision medicine.

Functional Precision Medicine in AML: Technical Performance Evaluation for in Vitro Diagnostics Using High-Throughput Image-Based Screening of Primary Patient Cells

Introduction: Identification of the right drug, for the right patient, at the right time is the defining goal for precision and personalized medicine programs. Many tools are currently being pursued for this including next-gen sequencing and other -omics approaches to determine target availability (Moscow et al, 2018 Nat Rev Clin Oncol.), functional drug response profiling in viable patient samples (Snijder et al, 2017 Lancet Haem), or a combination of both (Schmidl et al, 2019 Nat Chem Bio). Of those, functional precision medicine approaches are only just beginning to gain clinical interest, and because of this, nearly all programs lack systematic testing in prospective clinical studies (Letai, 2017 Nat Rev Med). One of the first functional precision medicine approaches to be tested in a small prospective clinical study was the use of high-throughput image-based screening and single cell analysis of drug response in primary tissues ("Pharmacoscopy") as a tool to prospectively rank drug options for patients with late-stage hematological indications (Snijder et al 2017, Lancet Haem, NCT03096821). In this study, taking Pharmacoscopy data into account for treatment selection led to a higher overall response rate (88% vs. 24%) and longer progression free survival (22.6 vs. 5.7 weeks) compared to the previous line of therapy. In order for functional precision medicine programs to reach widespread routine use, ultimately the development of fully-certified in vitro diagnostic test products will be required. This requires amongst others a systematic understanding of i) the technical robustness of functional drug testing approaches and ii) a detailed understanding of how pre-analytical sample handling influences assay results. Here, we set out to investigate two crucial questions that arose in the course of systematic assay development for AML: a) do CD34+ cells derived from peripheral blood and bone marrow AML patients respond differently to short term ex vivo treatment with small molecule drugs and b) does the overall response of these cells change upon cryopreservation? These issues are of high relevance even outside the setting of functional precision medicine development programs given worldwide biobanking efforts, and the lack of robust systematic model comparison. Methods: Fresh patient blood and bone marrow samples of newly diagnosed as well as relapsed and refractory patients with AML were collected at Medical University of Graz under appropriate ethics approval. Samples were divided into two parts and one part used immediately, the other cryopreserved as viable cells. The response of CD34+ cells against 140 different small molecule drugs (two concentrations and three technical replicates) was evaluated using single-cell high content microscopy (Allcyte's "Pharmacoscopy" platform) in both peripheral blood and bone marrow as well as freshly used and previously viably frozen samples. Drug response was determined by fitting to generalised linear and mixed models. Further, RNA is isolated from additional patient samples before and after biobanking for Nanostring analysis. Results: Overall, across all tested patient samples, we observed a high correlation between drug response tested in blood and bone marrow samples from this group of patient samples, indicating, at least for AML, no strong niche dependence for the drugs tested. Additionally, we also observed a high correlation between drug response tested in fresh and frozen tissues (Figure 1). The differences that did appear were, in particular, in drugs targeting metabolic and cell-growth dependent functions, amongst others. Conclusions: Understanding how biobanking affects the ex vivo drug response of primary human tissues is paramount to being able to understand how far translational efforts can go using tissues and functional drug response assays. We provide systematic data supporting the use of cryopreserved samples for the functional analysis of drug response in AML. This is a fundamental question associated with the use of biobanks for investigations of primary patient material. Figure 1 Disclosures Krall: Allcyte: Employment, Equity Ownership. Meszaros:Allcyte: Employment. Vilagos:Allcyte: Employment. Sill:Astellas: Other: Advisory board; Novartis: Other: Advisory board; Astex: Other: Advisory board; AbbVie: Other: Advisory board. Vladimer:Allcyte: Employment, Equity Ownership, Patents &amp; Royalties: EP3198276A1.

Inter-Cell Networking Profiling Enables Comprehensive Characterization of Immune-Mediated Activity of Anti-CD38 Therapy through Ex-Vivo Analysis of Multiple Myeloma Patients

Inter-Cell Networking Profiling Enables Comprehensive Characterization of Immune-Mediated Activity of Anti-CD38 Therapy through Ex-Vivo Analysis of Multiple Myeloma Patients

Synergistic Drug Combinations to Overcome Venetoclax Resistance in Multiple Myeloma

We have established a functional precision medicine platform to evaluate the chemosensitivity of 76 FDA-approved and clinical therapeutics relevant to multiple myeloma (MM), alone or in combinations, in human myeloma cell lines (HMCLs) and in primary MM samples. The panel includes the Bcl-2 inhibitor venetoclax, currently in clinical development. There is a pressing need to identify rational drug combinations that select for synergistic activity with venetoclax, overcome its resistance, and provide patients with less toxic treatment options.

Abstract 4478: High-throughput dynamic BH3 profiling identifies active cancer therapies in solid tumors

Abstract Phenotypic differences between primary patient tumors and models of tumors that are amenable to chemical screening represents a key barrier to drug discovery and drug repurposing. High-throughput technologies that can accurately identify active drugs using primary patient tumors are therefore valuable additions to the drug development toolbox and may have direct clinical utility as predictive biomarkers. Here we report a method called high-throughput dynamic BH3 profiling (HT-DBP), a robust microscopy-based assay with single-cell resolution that enables chemical screens of hundreds of candidate drugs on freshy isolated tumor cells to identify chemical inducers of mitochondrial apoptotic signaling. HT-DBP requires only 24 hours of ex vivo culture which enables the direct study of fresh primary tumor cells and minimizes adaptive changes that occur with prolonged ex vivo culture. Using 1650 compounds, we performed HT-DBP on freshly isolated cells from the MMTV-PyMT genetically engineered mouse model of breast cancer to identify drugs that sensitize these tumors for apoptosis. Selected compounds identified by HT-DBP induced regressions in the MMTV-PyMT genetically engineered mouse model of breast cancer in vivo, and in a patient derived xenograft model of breast cancer. To evaluate how chemical vulnerabilities evolve in cell culture, we performed HT-DBP on a cancer cell line from MMTV-PyMT tumors. We observe different patterns of chemical vulnerabilities between freshly isolated tumor cells and in the derived cell lines, which is consistent with the mixed track record of cancer cell line chemical screens. We demonstrate that HT-DBP can be used to generate personalized apoptotic chemical vulnerabilities (which we refer to as pharmacotypes) for a set of colon cancer PDX models. We find that a PDX model derived from a primary site tumor and a metastatic lesion from the same patient have different pharmacotypes. Using annotations of small molecule targets, we can identify proteins and signaling pathways that represent apoptotic vulnerabilities in colon PDX models. Finally, we apply HT-DBP to primary human thyroid tumors and sarcomas to identify potential active therapies. In sum, HT-DBP can efficiently predict therapeutic sensitivity upon short-term ex vivo drug exposure and may empower functional precision medicine approaches in the clinic. Citation Format: Patrick D. Bhola, Eman Ahmed, Jennifer Guerriero, Ewa Sicinska, Emily Su, Jing Ni, Elizaveta Lavrova, Otari Chipashvili, Timothy Hagan, Kimmie Ng, Andrew Aguirre, Jochen Lorch, Suzanne George, George Demetri, Jean Zhao, Anthony Letai. High-throughput dynamic BH3 profiling identifies active cancer therapies in solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4478.

Intertumoral heterogeneity in patient-specific drug sensitivities in treatment-na\xefve glioblastoma

BackgroundA major barrier to effective treatment of glioblastoma (GBM) is the large intertumoral heterogeneity at the genetic and cellular level. In early phase clinical trials, patient heterogeneity in response to therapy is commonly observed; however, how tumor heterogeneity is reflected in individual drug sensitivities in the treatment-naïve glioblastoma stem cells (GSC) is unclear.MethodsWe cultured 12 patient-derived primary GBMs as tumorspheres and validated tumor stem cell properties by functional assays. Using automated high-throughput screening (HTS), we evaluated sensitivity to 461 anticancer drugs in a collection covering most FDA-approved anticancer drugs and investigational compounds with a broad range of molecular targets. Statistical analyses were performed using one-way ANOVA and Spearman correlation.ResultsAlthough tumor stem cell properties were confirmed in GSC cultures, their in vitro and in vivo morphology and behavior displayed considerable tumor-to-tumor variability. Drug screening revealed significant differences in the sensitivity to anticancer drugs (p < 0.0001). The patient-specific vulnerabilities to anticancer drugs displayed a heterogeneous pattern. They represented a variety of mechanistic drug classes, including apoptotic modulators, conventional chemotherapies, and inhibitors of histone deacetylases, heat shock proteins, proteasomes and different kinases. However, the individual GSC cultures displayed high biological consistency in drug sensitivity patterns within a class of drugs. An independent laboratory confirmed individual drug responses.ConclusionsThis study demonstrates that patient-derived and treatment-naïve GSC cultures maintain patient-specific traits and display intertumoral heterogeneity in drug sensitivity to anticancer drugs. The heterogeneity in patient-specific drug responses highlights the difficulty in applying targeted treatment strategies at the population level to GBM patients. However, HTS can be applied to uncover patient-specific drug sensitivities for functional precision medicine.

Implementation of functional precision medicine for anaplastic lymphoma kinase-rearranged non-small lung cancer

Anaplastic lymphoma kinase (ALK)-rearranged kinase drives non-small cell lung cancer (NSCLC) in 3–7% of patients and treatment consists of a broad range of approved inhibitors which are administered sequentially in case of resistance developing invariably after approximately 1 year of therapy. Besides the former standard tyrosine kinase inhibitor (TKI) crizotinib, the second-line ALK inhibitors alectinib, ceritinib, brigatinib, as well as the third-line lorlatinib are approved for the treatment of ALK-positive NSCLC patients. The main challenge is to find individual schemes of ALK inhibitors therapy which provide the best benefit for the patients. A host of ALK fusion partners, rearrangement variants and ALK mutations prevent a direct correlation of ALK alterations and sensitivity to specific TKIs within the framework of genomic precision medicine. However, recurrent ALK-positive NSCLC is an aggressive disease resulting in accumulation of tumor cells in pleural effusions which may be collected for in vitro sensitivity testing in a manner designated as functional precision medicine. Provided that these cells are present in sufficient numbers, they can be exposed to all possible drug candidates and their chemosensitivity tested in short-term proliferation assays. In addition to ALK-directed TKIs, cytotoxic drugs and inhibitors of non-target bypassing pathways may be included in the tests. In contrast to other trials in genome-guided precision medicine, a range of suitable therapeutics is available for modified ALK proteins. In summary, ALK-positive NSCLC with pleural effusions offer a unique model to develop, test and validate concepts of functional precision medicine.

Functional Precision Medicine Identifies Novel Druggable Targets and Therapeutic Options in Head and Neck Cancer.

Purpose: Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer worldwide, with high mortality and a lack of targeted therapies. To identify and prioritize druggable targets, we performed genome analysis together with genome-scale siRNA and oncology drug profiling using low-passage tumor cells derived from a patient with treatment-resistant HPV-negative HNSCC.Experimental Design: A tumor cell culture was established and subjected to whole-exome sequencing, RNA sequencing, comparative genome hybridization, and high-throughput phenotyping with a siRNA library covering the druggable genome and an oncology drug library. Secondary screens of candidate target genes were performed on the primary tumor cells and two nontumorigenic keratinocyte cell cultures for validation and to assess cancer specificity. siRNA screens of the kinome on two isogenic pairs of p53-mutated HNSCC cell lines were used to determine generalizability. Clinical utility was addressed by performing drug screens on two additional HNSCC cell cultures derived from patients enrolled in a clinical trial.Results: Many of the identified copy number aberrations and somatic mutations in the primary tumor were typical of HPV(-) HNSCC, but none pointed to obvious therapeutic choices. In contrast, siRNA profiling identified 391 candidate target genes, 35 of which were preferentially lethal to cancer cells, most of which were not genomically altered. Chemotherapies and targeted agents with strong tumor-specific activities corroborated the siRNA profiling results and included drugs that targeted the mitotic spindle, the proteasome, and G2-M kinases WEE1 and CHK1 We also show the feasibility of ex vivo drug profiling for patients enrolled in a clinical trial.Conclusions: High-throughput phenotyping with siRNA and drug libraries using patient-derived tumor cells prioritizes mutated driver genes and identifies novel drug targets not revealed by genomic profiling. Functional profiling is a promising adjunct to DNA sequencing for precision oncology. Clin Cancer Res; 24(12); 2828-43. ©2018 AACR.

Voruciclib, a clinical stage oral CDK9 inhibitor, represses MCL-1 and sensitizes high-risk Diffuse Large B-cell Lymphoma to BCL2 inhibition

Aberrant regulation of BCL-2 family members enables evasion of apoptosis and tumor resistance to chemotherapy. BCL-2 and functionally redundant counterpart, MCL-1, are frequently over-expressed in high-risk diffuse large B-cell lymphoma (DLBCL). While clinical inhibition of BCL-2 has been achieved with the BH3 mimetic venetoclax, anti-tumor efficacy is limited by compensatory induction of MCL-1. Voruciclib, an orally bioavailable clinical stage CDK-selective inhibitor, potently blocks CDK9, the transcriptional regulator of MCL-1. Here, we demonstrate that voruciclib represses MCL-1 protein expression in preclinical models of DLBCL. When combined with venetoclax in vivo, voruciclib leads to model-dependent tumor cell apoptosis and tumor growth inhibition. Strongest responses were observed in two models representing high-risk activated B-cell (ABC) DLBCL, while no response was observed in a third ABC model, and intermediate responses were observed in two models of germinal center B-cell like (GCB) DLBCL. Given the range of responses, we show that CIVO, a multiplexed tumor micro-dosing technology, represents a viable functional precision medicine approach for differentiating responders from non-responders to BCL-2/MCL-1 targeted therapy. These findings suggest that the combination of voruciclib and venetoclax holds promise as a novel, exclusively oral combination therapy for a subset of high-risk DLBCL patients.