Integrating novel drugs to chemoimmunotherapy in diffuse large B-cell lymphoma

Decreased RNA‑binding protein IGF2BP2 downregulates NT5DC2, which suppresses cell proliferation, and induces cell cycle arrest and apoptosis in diffuse large B‑cell lymphoma cells by regulating the p53 signaling pathway

Diffuse large B‑cell lymphoma (DLBCL) remains difficult to treat clinically due to its highly aggressive characteristics. Insulin‑like growth factor 2 mRNA‑binding protein 2 (IGF2BP2) and 5'‑nucleotidase domain‑containing 2 (NT5DC2) have been suggested as potential regulators in numerous types of cancer. The present study aimed to determine whether downregulation of IGF2BP2 and NT5DC2 suppresses cell proliferation, and induces cell cycle arrest and apoptosis in DLBCL cells by regulating the p53 signaling pathway. The expression levels of IGF2BP2 and NT5DC2 in DLBCL cells were determined by reverse transcription‑quantitative PCR (RT‑qPCR) and western blot analysis. Transfection of cells with IGF2BP2 overexpressing plasmids and NT5DC2 interference plasmids was performed, and the efficacy of transfection was confirmed by RT‑qPCR and western blot analysis. The viability, proliferation, cell cycle progression and apoptosis of DLBCL cells were analyzed by Cell Counting Kit‑8 assay, 5‑bromo‑2‑deoxyuridine staining and flow cytometry. RNA pull‑down and immunoprecipitation assays were used to verify the binding of IGF2BP2 and NT5DC2. The expression levels of apoptosis, cell cycle and p53 pathway‑associated proteins were determined by western blotting. The results revealed that NT5DC2 expression was increased in DLBCL cell lines and was the highest in OCI‑Ly7 cells. IGF2BP2 expression was also increased in OCI‑Ly7 cells and IGF2BP2 bound to NT5DC2. Knockdown of NT5DC2 suppressed cell viability and proliferation, induced cell cycle arrest and promoted apoptosis in DLBCL cells, which was reversed by upregulation of IGF2BP2. In addition, knockdown of NT5DC2 increased the expression of p53 and p21, but suppressed the expression of proliferating cell nuclear antigen, CDK4 and cyclin D1; these effects were reversed by upregulation of IGF2BP2. In conclusion, knockdown of NT5DC2 suppressed cell viability and proliferation, induced cell cycle arrest and promoted apoptosis in DLBCL cells by regulating the p53 signaling pathway and these effects were reversed by upregulation of IGF2BP2.

Patient Perspectives on Health-Related Quality of Life in Diffuse Large B-Cell Lymphoma Treated with Car T-Cell Therapy: A Qualitative Study

Introduction

Chimeric antigen receptor T-cell (CAR T) therapy offers a potentially curative option for patients with relapsed and refractory hematologic malignancies, including diffuse large B-cell lymphoma (DLBCL). Patient-reported experiences with CAR T therapy are limited and have not been well characterized. The purpose of this qualitative study was to explore patient descriptions of key domains of health-related quality of life (HRQoL) in DLBCL patients treated with CAR T therapy.

Methods

A targeted literature review was initially conducted to inform the development of the interview guide comprising predetermined open-ended questions. Two focus groups were conducted with a total of 18 patients with DLBCL identified from patient advisory boards. Focus group sessions were recorded and transcribed verbatim. MAXQDA 18.2.0 qualitative data analysis software was utilized to facilitate a constant-comparative coding process to identify key concepts.

Results

Eight domain impairments (social functioning, emotional functioning, fatigue, physical functioning, cognitive functioning, role functioning, sleep, and pain/discomfort) were identified from the qualitative analysis and endorsed by DLBCL patients treated with CAR T. Compared with before CAR T therapy, patients reported increased impairment in every domain during or immediately after CAR T therapy. This impairment improved for each domain 6 months after CAR T therapy except for pain/discomfort. Compared with before CAR T therapy, improvement in impairment for each domain was observed 6 months after CAR T therapy except for fatigue, sleep, and pain/discomfort.

Conclusion

This study provides meaningful information regarding the impact of CAR T therapy on HRQoL in patients with DLBCL throughout their treatment journey. Health care professionals and investigators can utilize these data in examining existing patient-reported outcome (PRO) measures that are used in DLBCL clinical trials and to better understand the needs of DLBCL survivors.

A concise prognostic score system for diffuse large B-cell lymphoma: a retrospective study with long-term follow-up

Aim: To identify risk factors and establish a concise prognostic scoring system in patients with diffuse large B-cell lymphoma (DLBCL). Methods: A total of 131 DLBCL patients were enrolled with long-term follow-up who were treated in Shengjing Hospital of the China Medical University. The relationship between clinical parameters and outcomes was analyzed. Results: Multivariate analysis showed that patient age, BMI, CA125 and rituximab application were independent risk factors. Thereafter, a concise scoring system was established, and the new system could identify high-risk patients (p < 0.0001). The patients were divided into three groups: low-risk, medium-risk and high-risk groups. There were significant differences among different groups on overall survival and progression-free survival by log-rank test (p < 0.05). Conclusion: Old age, low BMI, high CA125 and no rituximab application were independent risk factors for DLBCL. The new established prognostic score system, which includes all the risk factors, could identify high-risk patients.

An Overview on Diffuse Large B-Cell Lymphoma Models: Towards a Functional Genomics Approach

Simple Summary

Lymphoma research is a paradigm of integrating basic and applied research within the fields of molecular marker-based diagnosis and therapy. In recent years, major advances in next-generation sequencing have substantially improved the understanding of the genomics underlying diffuse large B-cell lymphoma (DLBCL), the most frequent type of B-cell lymphoma. This review addresses the various approaches that have helped unveil the biology and intricate alterations in this pathology, from cell lines to more sophisticated last-generation experimental models, such as organoids. We also provide an overview of the most recent findings in the field, their potential relevance for designing targeted therapies and the corresponding applicability to personalized medicine.

Abstract

Lymphoma research is a paradigm of the integration of basic and clinical research within the fields of diagnosis and therapy. Clinical, phenotypic, and genetic data are currently used to predict which patients could benefit from standard treatment. However, alternative therapies for patients at higher risk from refractoriness or relapse are usually empirically proposed, based on trial and error, without considering the genetic complexity of aggressive B-cell lymphomas. This is primarily due to the intricate mosaic of genetic and epigenetic alterations in lymphomas, which are an obstacle to the prediction of which drug will work for any given patient. Matching a patient’s genes to drug sensitivity by directly testing live tissues comprises the “precision medicine” concept. However, in the case of lymphomas, this concept should be expanded beyond genomics, eventually providing better treatment options for patients in need of alternative therapeutic approaches. We provide an overview of the most recent findings in diffuse large B-cell lymphomas genomics, from the classic functional models used to study tumor biology and the response to experimental treatments using cell lines and mouse models, to the most recent approaches with spheroid/organoid models. We also discuss their potential relevance and applicability to daily clinical practice.

Targeting Bcl-2 for cancer therapy

Apoptosis deficiency is one of the most important features observed in neoplastic diseases. The Bcl-2 family is composed of a subset of proteins that act as decisive apoptosis regulators. Research and clinical studies have both demonstrated that the hyperactivation of Bcl-2-related anti-apoptotic effects correlates with cancer occurrence, progression and prognosis, also having a role in facilitating the radio- and chemoresistance of various malignancies. Therefore, targeting Bcl-2 inactivation has provided some compelling therapeutic advantages by enhancing apoptotic sensitivity or reversing drug resistance. Therefore, this pharmacological route turned into one of the most promising routes for cancer treatment. This review discusses some of the well-defined and emerging roles of Bcl-2 as well as its potential clinical value in cancer therapeutics.

High total metabolic tumor volume at baseline predicts survival independent of response to therapy

Early identification of ultra-risk diffuse large B-cell lymphoma (DLBCL) patients is needed to aid stratification to innovative treatment. Previous studies suggested high baseline total metabolic tumor volume (TMTV) negatively impacts survival of DLBCL patients. We analyzed the prognostic impact of TMTV and prognostic indices in DLBCL patients, aged 60 to 80 years, from the phase 3 REMARC study that randomized responding patients to R-CHOP (rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone) into maintenance lenalidomide or placebo. TMTV was computed on baseline positron emission tomography/computed tomography using the 41% maximum standardized uptake value method; the optimal TMTV cutoff for progression-free (PFS) and overall survival (OS) was determined and confirmed by a training validation method. There were 301 out of 650 evaluable patients, including 192 patients classified as germinal center B-cell-like (GCB)/non-GCB and MYC/BCL2 expressor. Median baseline TMTV was 238 cm3; optimal TMTV cutoff was 220 cm3. Patients with high vs low TMTV showed worse/higher Eastern Cooperative Oncology Group performance status (ECOG PS) ≥2, stage III or IV disease, >1 extranodal site, elevated lactate dehydrogenase, International Prognostic Index (IPI) 3-5, and age-adjusted IPI 2-3. High vs low TMTV significantly impacted PFS and OS, independent of maintenance treatment. Although the GCB/non-GCB profile and MYC expression did not correlate with TMTV/survival, BCL2 >70% impacted PFS and could be stratified by TMTV. Multivariate analysis identified baseline TMTV and ECOG PS as independently associated with PFS and OS. Even in responding patients, after R-CHOP, high baseline TMTV was a strong prognosticator of inferior PFS and OS. Moreover, TMTV combined with ECOG PS may identify an ultra-risk DLBCL population. This trial was registered at www.clinicaltrials.gov as #NCT01122472.

MiR-645 regulates the proliferation and apoptosis of diffuse large B-cell lymphoma by targeting DACH1

Diffuse large B-cell lymphoma (DLBCL) is the most common subtype of malignant non-Hodgkin lymphoma cases. An increasing body of evidence has indicated the critical roles of microRNAs (miRNAs) in regulating the progression of DLBCL. In this study, we found that miR-645 was up-regulated in DLBCL tissues and cell lines. Down-regulation of miR-645 significantly inhibited the proliferation, cell cycle progression and promoted the apoptosis of DLBCL cells. Experimental study identified Dachshund family transcription factor 1 (DACH1) as a target of miR-645. MiR-645 bound the 3'-untranslated region of DACH1 and reduced the expression of DACH1 in DLBCL cells. Decreased expression of DACH1 was inversely correlated with that of miR-645 in DLBCL tissues. The promoting effect of miR-645 on the proliferation of DLBCL cells was attenuated with the overexpression of DACH1. These results demonstrated the novel mechanism of miR-645 in DLBCL, which indicated miR-645 as a potential target for the diagnosis and prognostics of DLBCL.

Direct-acting antivirals in relapsed or refractory hepatitis C virus-associated diffuse large B-cell lymphoma

Recent studies have demonstrated feasibility and substantial benefit of direct-acting antivirals (DAAs) administration during or after first-line immune-chemotherapy (I-CT) in patients with hepatitis C virus (HCV)-positive diffuse large B-cell lymphomas (DLBCL). However, data on DAAs used during or after salvage treatments are still lacking. In this study we assessed clinical and virological outcome in 11 patients with relapsed (n = 7) or refractory (n = 4) HCV-positive DLBCL. DAAs were given either concurrently (n = 3) or subsequent (n = 8) to salvage I-CT. Most patients (10 of 11) received sofosbuvir-based regimens. All patients completed their planned courses of DAAs and achieved sustained virological response. DAAs were well tolerated, with no grade ≥2 adverse events. At a median follow-up of 3.6 years four patients died (4-year OS: 76%). In conclusion, we provide evidence that DAAs in HCV-positive relapsed/refractory DLBCL are extremely safe and effective, suggesting that they should be used if HCV eradication was not instituted before.

Novel cyclophosphamide of natural products osalmide and pterostilbene induces cytotoxicity and cell cycle arrest in diffuse large B-cell lymphoma cells

Diffuse large B-cell lymphoma (DLBCL) is the most common category and disease entity of non-Hodgkin lymphoma. Osalmide and pterostilbene are natural products with anticancer activities via different mechanism. In this study, using a new synthetic strategy for the two natural products, we obtained the compound DCZ0801, which was previously found to have anti-multiple myeloma activity. We performed both in vitro and in vivo assays to investigate its bioactivity and explore its underlying mechanism against DLBCL cells. The results showed that DCZ0801 treatment gave rise to a dose- and time-dependent inhibition of cell viability as determined by CCK-8 assay and flow cytometry assay. Western blot analysis results showed that the expression of caspase-3, caspase-8, caspase-9 and Bax was increased, while BCL-2 and BCL-XL levels were decreased, which suggested that DCZ0801 inhibited cell proliferation and promoted intrinsic apoptosis. In addition, DCZ0801 induced G0/G1 phase arrest by downregulating the protein expression levels of CDK4, CDK6 and cyclin D1. Furthermore, DCZ0801 exerted an anti-tumor effect by down-regulating the expressions of p-PI3K and p-AKT. There also existed a trend that the expression of p-JNK and p-P38 was restrained. Intraperitoneal injection of DCZ0801 suppressed tumor development in xenograft mouse models. The preliminary metabolic study showed that DCZ0801 displayed a rapid metabolism within 30 min. These results demonstrated that DCZ0801 may be a new potential anti-DLBCL agent in DLBCL therapy.

TIMD4 exhibits regulatory capability on the proliferation and apoptosis of diffuse large B-cell lymphoma cells via the Wnt/β-catenin pathway

BACKGROUND

Prior studies have noted the importance of T cell immunoglobulin and mucin domain containing 4 (TIMD4) in various diseases and its functions on cell malignant behaviors. However, the biological function of TIMD4 in diffuse large B-cell lymphoma (DLBCL) is unknown.

METHODS

Relative expression of TIMD4 was analyzed based on the GSE56315 array including 88 cases of human tissues. TIMD4 expression in cells was detected using a quantitative reverse transcriptase-polymerase chain reaction and western blot experiments. Cell proliferation was measured using the cell counting kit-8 (CCK-8) assay and apoptotic properties were assessed through the detection of related proteins by western blotting. The underlying molecular mechanism of TIMD4 in DLBCL was predicted and confirmed using KEGG enrichment analysis and western blotting.

RESULTS

The results indicate that TIMD4 is overexpressed in DLBCL tissues and the poor prognosis of DLBCL patients is significantly linked with the higher TIMD4 expression. The loss-of-TIMD4 experiment in CYP6D reveals that knockdown of TIMD4 blocks cell growth and accelerates cell apoptosis, whereas the gain-of-TIMD4 experiment in Raji cells suggests that up-regulation of TIMD4 promotes cell proliferation and inhibits cell apoptosis. The activity of the Wnt/β-catenin pathway is mediated by the TIMD4 expression in DLBCL cells.

CONCLUSIONS

These findings demonstrate that TIMD4 is up-regulated in patients with DLBCL and the regulatory effects of TIMD4 on cell proliferation and apoptosis are associated with the Wnt/β-catenin pathway, posing a novel target for DLBCL therapy.

Lenalidomide maintenance for diffuse large B-cell lymphoma patients responding to R-CHOP: quality of life, dosing, and safety results from the randomised controlled REMARC study

Lenalidomide maintenance therapy prolonged progression‐free survival (PFS) versus placebo in elderly patients with diffuse large B‐cell lymphoma (DLBCL) responding to induction chemotherapy in the phase 3 REMARC study. This subpopulation analysis assessed the impact of lenalidomide maintenance and treatment‐emergent adverse events (TEAEs) on health‐related quality of life (HRQOL). Global health status (GHS), and physical functioning and fatigue subscales were evaluated in patients who completed the European Organisation for Research and Treatment of Cancer quality‐of‐life questionnaire‐C30 v3.0. The impact of TEAEs classified post hoc as subjective (patients can feel) or observable (only measurable by physicians) on dose reductions and discontinuations was assessed. Among 457 patients (lenalidomide, n = 229; placebo, n = 228), mean (standard deviation) GHS was similar between treatment arms [68·2 (20·7) Versus 72·0 (17·8)] at randomisation and remained similar during maintenance. Patients receiving lenalidomide experienced no meaningful changes in GHS, physical functioning, or fatigue. Observable TEAEs were more common (81·1% Versus 66·3%) and more likely to lead to dose reductions, than subjective TEAEs in both arms. PFS was superior in the lenalidomide arm regardless of dose reduction. Lenalidomide maintenance prolonged PFS and did not negatively impact HRQOL in patients with DLBCL despite TEAEs being more common, when compared with placebo.

An Engineered Fusion Protein Anti-CD19(Fab)-LDM Effectively Inhibits ADR-Resistant B Cell Lymphoma

The 5-year survival rate of patients with B cell lymphoma is about 50% after initial diagnosis, mainly because of resistance to chemotherapy. Hence, it is necessary to understand the mechanism of chemo-resistance and to explore novel methods to circumvent multidrug resistance. Previously, we showed that an engineered cytotoxic fusion protein anti-CD19(Fab)-LDM (lidamycin), can induce apoptosis of B-lymphoma cells. Herein, we successfully established an adriamycin (ADR)-resistant B cell lymphoma cell line BJAB/ADR. The mRNA and protein level of ATP-binding cassette subfamily B member 1 (ABCB1) were significantly overexpressed in BJAB/ADR cells. Increased efflux function of ABCB1 was observed by analyzing intracellular accumulation and efflux of Rhodamine 123. The efflux of Rhodamine 123 could be significantly ameliorated by verapamil. Treatment with anti-CD19(Fab)-LDM at different concentrations induced cytotoxic response of BJAB/ADR cells similar to that of the sensitive cells. In vivo studies showed that anti-CD19(Fab)-LDM had better antitumor effect in BJAB and BJAB/ADR cell lymphoma xenografts compared with ADR or LDM treatment alone. Taken together, anti-CD19(Fab)-LDM can effectively inhibit the growth of BJAB/ADR cells both in vitro and in vivo. Anti-CD19(Fab)-LDM could be a promising molecule for the treatment of drug resistant cancers.

Immunoglobulin D (IgD) and IgD receptor expression in diffuse large B-cell lymphoma

Objective: Immunoglobulin D (IgD) levels are often elevated in patients with autoimmune diseases. However, the oncogenic activities of IgD and IgD receptor (IgDR) in diffuse large B-cell lymphoma (DLBCL) have not been reported in detail. Therefore, we aimed to investigate the expression of IgD and IgDR in patients with DLBCL. Methods: Membrane IgD (mIgD) and IgDR expression in tissue samples was analyzed using IHC, mIgD and IgDR expression on peripheral blood mononuclear cells (PBMCs) was analyzed by FCM, and secreted IgD (sIgD) level was analyzed by ELISA. Fisher's exact test and Spearman correlation analysis were used to evaluate the relationship between IgD, IgDR, and clinical parameters. Results: The pathological lymph nodes of 34 patients with DLBCL were studied, and mIgD and IgDR expression was found in 16 and 19 patients. mIgD and IgDR expression was upregulated in patients with DLBCL and mIgD expression was significantly associated with IgDR expression. Further correlation analysis showed that mIgD expression was correlated with serum β₂-MG level and Hans algorithm as germinal center B (GCB), whereas IgDR expression correlated with serum LDH level, IPI score and GCB. ELISA showed that sIgD level was significantly increased in DLBCL patients and it correlated with serum β₂-MG and LDH levels. FCM showed that mIgD and IgDR expression in PBMCs of patients with DLBCL was significantly higher than that in healthy controls. Conclusion: Our findings suggest that overexpression of IgD and IgDR is an abnormal activation state in DLBCL.

Soluble CXCL16 promotes TNF-α-induced apoptosis in DLBCL via the AMAD10-NF-κB regulatory feedback loop

We had previously identified that the co-expression of transmembrane CXCL16 (TM-CXCL16) and its receptor CXCR6 is an independent risk factor for poor survival in patients with diffuse large B-cell lymphoma (DLBCL). However, the impact of the soluble form of CXCL16 (sCXCL16) on the pathogenesis of DLBCL remains unknown. In the present study, the synergistic effect of sCXCL16 and tumor necrosis factor α (TNF-α) on apoptosis in DLBCL cell lines (OCI-LY8 and OCI-LY10) was investigated in vitro. sCXCL16 reinforced TNF-α-mediated inhibition of DLBCL cell proliferation, as determined by the cell counting kit-8 assay. The results of annexin V staining showed that sCXCL16 enhanced TNF-α-induced apoptosis in OCI-LY8 and OCI-LY10 cells through a death receptor-caspase signaling pathway. The results of gene microarray suggested a significant upregulation of differentially expressed genes in the TNF signaling pathway. sCXCL16 increased the concentration of extracellular TNF-α by binding to CXCR6 to activate the nuclear factor-κB (NF-κB) signaling pathway. TNF-α also induced the secretion of sCXCL16 by increasing the expression of ADAM10, which is known to cleave TM-CXCL16 to yield sCXCL16. Moreover, bioinformatics analysis revealed that elevated TNF-α and ADAM10 expression levels in tumor tissues predicted better survival in patients with DLBCL. Thus, our study suggests that sCXCL16 enhances TNF-α-induced apoptosis of DLBCL cells, which may involve a positive feedback loop consisting of TNF-α, ADAM10, sCXCL16, and members of the NF-κB pathway. sCXCL16 and TNF-α may be used as prognostic markers in the clinic, and their combinational use is a promising approach in the context of DLBCL therapy.

Indolent T-cell lymphoproliferative disease with synchronous diffuse large B-cell lymphoma: A case report

RATIONALE

Indolent T-cell lymphoproliferative disease (T-LPD) of gastrointestinal tract is a rare recently described disease that seldom progresses. We report a case of T-LPD with synchronous diffuse large B-cell lymphoma (DLBCL) that cause aggravation of disease.

PATIENT CONCERNS

A 46-year-old Chinese male presented with intermittent paraumbilical colic pain, bloating, and occasional diarrhea for 10 years. His condition aggravated with partial bowel obstruction recently. The patient was diagnosed as T-LPD initially based on histological result and T-cell receptor-gamma clonal gene rearrangement test. The patient was followed without chemotherapy. His condition stabilized for 1 year and then deteriorated with small intestine perforation.

DIAGNOSIS

The patient was diagnosed as indolent T-LPD and DLBCL finally.

INTERVENTIONS

The patient had surgery for intestine perforation and received chemotherapy for DLBCL and T-LPD afterward.

OUTCOMES

At 6 months follow-up, the patient continued to have resolution of his symptoms.

LESSONS

Early detection of high-grade transformation of T-LPD or the coexistence of aggressive lymphoma is essential for the patient. DLBCL may coexist in the indolent course of T-LPD. The diagnosis of T-LPD should be made cautiously in case with progressing symptoms such as intestinal obstruction.

Rituximab (anti-CD20)-modified AZD-2014-encapsulated nanoparticles killing of B lymphoma cells

The mTOR signal pathway is often highly activated in B-cell non-Hodgkin's lymphoma (NHL) and promotes cancer progression and chemo-resistance. Therefore, the pathways of mTOR are an important target for drug development in this disease. In the current study, we developed a rituximab (anti-CD20)-modified mTOR inhibitor, AZD-2014, loaded into nanoparticles (Ab-NPs-AZD-2014) for trial of its anti-NHL effect. In a cultured NHL cell line, Ab-NPs-AZD-2014 inhibited cancer cell growth, induced cell apoptosis, and blocked activation of mTORC1 and mTORC2 in Raji cells. These results indicate that antibody modification and nanomaterial loading of AZD-2014 with anti-CD20 significantly improved efficacy of AZD-2014 against NHL cells. This approach may ultimately deserve testing in therapy against NHL.

Molecular heterogeneity in diffuse large B-cell lymphoma and its implications in clinical diagnosis and treatment

Over half of patients with diffuse large B-cell lymphoma (DLBCL) can be cured by standard R-CHOP treatment (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone). However, the remaining patients are refractory and ultimately succumb to progressive or relapsed disease. During the past decade, there has been significant progress in the understanding of molecular mechanisms in DLBCL, largely owing to collaborative efforts in large-scale gene expression profiling and deep sequencing, which have identified genetic alterations critical in lymphomagenesis through activation of key signaling transduction pathways in DLBCL. These discoveries have not only led to the development of targeted therapies, including several currently in clinical trials, but also laid a solid foundation for the future identification of more effective therapies for patients not curable by R-CHOP. This review summarizes the recent advances in our understanding of the molecular characterization and pathogenesis of DLBCL and new treatment directions.

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.