Mantle cell lymphoma (MCL) is a mature B-cell lymphoma considered to be incurable with current treatments, including first-line rituximab in combination with multiagent chemotherapy and for those ...eligible, high-dose chemotherapy and stem cell support or rituximab maintenance. On the other hand, achieving a complete remission by high-sensitive flow cytometry is associated with prolonged duration of remission, stressing the need to develop and/or incorporate novel agents into the management of MCL. To this end, we examined the activity of ofatumumab, an anti-CD20 monoclonal antibody with distinct binding and immunologic properties compared to rituximab, in MCL preclinical models.
MCL cells were labeled with (51)Cr before incubation with rituximab or ofatumumab (10 μg/mL) plus human serum or effector cells. (51)Cr-release was measured and the percentage of lysis was calculated. Surface CD20, CD55, and CD59 were measured by Imagestream analysis. SCID mice inoculated subcutaneously with Z138 cells were assigned to control versus four doses of ofatumumab or rituximab (10 mg/kg/dose).
Ofatumumab exhibited enhanced in vitro complement-dependent cytotoxicity activity compared with rituximab in MCL cell lines, despite a high degree of in vitro resistance to rituximab associated with low CD20 levels and/or high expression of complement inhibitory proteins. Ofatumumab also delayed tumor progression and prolonged survival in a murine model of MCL.
Our results demonstrate that ofatumumab is more effective than rituximab in MCL preclinical models, including in the presence of rituximab resistance, and support the clinical investigation of ofatumumab in combination with standard systemic chemotherapy in MCL (NCT01527149).
In order to identify cellular pathways associated with therapy-resistant aggressive lymphoma, we generated rituximab-resistant cell lines (RRCL) and found that the acquirement of rituximab resistance ...was associated with a deregulation in glucose metabolism and an increase in the apoptotic threshold leading to chemotherapy resistance. Hexokinase II (HKII), the predominant isoform overexpressed in cancer cells, has dual functions of promoting glycolysis as well as inhibiting mitochondrial-mediated apoptosis. We found that RRCL demonstrated higher HKII levels. Targeting HKII resulted in decreased mitochondrial membrane potential, ATP production, cell viability; and re-sensitization to chemotherapy agents. Analyzed gene expression profiling data from diffuse large B-cell lymphoma patients, high-HKII levels were associated with a shorter progression free survival (PFS) and/or overall survival (OS). Our data suggest that over-expression of HKII is associated with resistance to rituximab and chemotherapy agents in aggressive lymphoma and identifies this enzyme isoform as a potential therapeutic target.
MDM2 and MDM4 proteins are key negative regulators of tumor suppressor p53. MDM2 and MDM4 interact
their RING domains and form a heterodimer polyubiquitin E3 ligase essential for p53 degradation. ...MDM4 also forms heterodimer E3 ligases with MDM2 isoforms that lack p53-binding domains, which regulate p53 and MDM4 stability. We are working to identify small-molecule inhibitors targeting the RING domain of MDM2-MDM4 (MMRi) that can inactivate the total oncogenic activity of MDM2-MDM4 heterodimers. Here, we describe the identification and characterization of MMRi62 as an MDM4-degrader and apoptosis inducer in leukemia cells. Biochemically, in our experiments, MMRi62 bound to preformed RING domain heterodimers altered the substrate preference toward MDM4 ubiquitination and promoted MDM2-dependent MDM4 degradation in cells. This MDM4-degrader activity of MMRi62 was found to be associated with potent apoptosis induction in leukemia cells. Interestingly, MMRi62 effectively induced apoptosis in p53 mutant, multidrug-resistant leukemia cells and patient samples in addition to p53 wild-type cells. In contrast, MMRi67 as a RING heterodimer disruptor and an enzymatic inhibitor of the MDM2-MDM4 E3 complex lacked MDM4-degrader activity and failed to induce apoptosis in these cells. In summary, this study identifies MMRi62 as a novel MDM2-MDM4-targeting agent and suggests that small molecules capable of promoting MDM4 degradation may be a viable new approach to killing leukemia cells bearing non-functional p53 by apoptosis.
Background
Ofatumumab is a humanized type 1 anti‐CD20 monoclonal antibody. Preclinical studies show improved complement‐mediated cytotoxicity (CMC) compared to rituximab in mantle cell lymphoma ...(MCL). This study evaluates the safety and efficacy of combining ofatumumab with HyperCVAD/MA (O‐HyperCVAD) in newly diagnosed MCL.
Methods
In this single‐arm phase 2 study, 37 patients were treated with the combination of O‐HyperCVAD for 4 or 6 cycles, followed by high dose chemotherapy and autologous stem cell transplant. Primary objectives were overall response rate (ORR) and complete response (CR) rate at the end of therapy. Secondary objectives included minimal residual disease (MRD) negativity, progression‐free survival (PFS), and overall survival (OS).
Results
Median age was 60 years; ORR was 86% and 73% achieved a CR by modified Cheson criteria. The MRD negativity rate was 78% after 2 cycles of therapy, increasing to 96% at the end of induction; median PFS and OS were 45.5 months and 56 months, respectively. Achieving a post‐induction CR by both imaging and flow cytometry was associated with improved PFS and OS. Early MRD negativity (post‐2 cycles) was also associated with an improved PFS but not OS. There were 3 deaths while on therapy, and grades 3 and 4 adverse events (AEs) were observed in 22% and 68% of the patients.
Conclusion
The addition of ofatumumab to HyperCVAD/HD‐MA led to high rates of MRD negativity by flow cytometry in patients with newly diagnosed MCL. Achieving a CR post‐induction by both imaging and flow cytometry is associated with improved overall survival.
Ofatumumab combined with HyperCVAD/MA results in high response rates and minimal residual disease negativity in patients with newly diagnosed mantle cell lymphoma. Achieving a post‐induction complete response by both imaging and flow cytometry was associated with improved survival rates.
Background
In patients with relapsed/refractory (R/R) diffuse large B-cell lymphoma (DLBCL), salvage chemotherapy regimens (e.g., rituximab, ifosfamide, carboplatin, and etoposide, R-ICE) yield poor ...outcomes. Carfilzomib, an irreversible proteasome inhibitor, can overcome acquired rituximab-chemotherapy resistance and, when combined with R-ICE, improves outcomes in patients with R/R DLBCL.
Objective
This analysis aimed to develop a population pharmacokinetic/pharmacodynamic (PK/PD) model for carfilzomib in R/R DLBCL patients.
Patients and Methods
In a single-center, open-label, prospective phase 1 study, patients received carfilzomib (10, 15, or 20 mg/m
2
) on days 1, 2, 8, and 9, and standard doses of R-ICE on days 3–6 every 21 days (maximum of three cycles). Carfilzomib plasma concentrations up to 24 h postinfusion were measured by liquid chromatography coupled with tandem mass spectrometry. Proteasome activity (PD biomarker) in peripheral blood mononuclear cells was assessed on days 1–2 with sparse sampling. PK/PD models were developed using NONMEM v7.4.1 interfaced with Finch Studio v1.1.0 and PsN v4.7.0. Model selection was guided by objective function value, goodness‐of‐fit, and visual predictive checks. Stepwise covariate modeling was used for covariate selection.
Results
Twenty-eight patients were enrolled in the PK/PD analysis, from whom 217 PK samples and 127 PD samples were included. Carfilzomib PK was best described by a two-compartment model with linear disposition (typical total clearance of 133 L/h). Proteasome activity was best characterized using a turnover model with irreversible inactivation. All parameters were estimated with good precision. No statistically significant covariates were identified.
Conclusions
A validated population-based PK/PD model of carfilzomib was developed successfully. Further research is needed to identify sources of variability in response to treatment with carfilzomib in combination with R-ICE.
Clinical Trial Registration
ClinicalTrials.gov identifier number NCT01959698.
Serologic biomarker to predict clinical outcome is needed for immune checkpoint inhibitors (ICIs). We evaluated soluble intercellular adhesion molecules‐1 (sICAM‐1) as a predictor of response to ICIs ...treatment. Ninety‐five patients with cancer treated with ICI were studied. The serum sICAM‐1 levels of baseline, post two cycle therapy and end of therapy (EOT) were measured by enzyme‐linked immunoassay. We randomly assigned the patients into the primary cohort (n = 47) and validation cohort (n = 48). Serum sICAM‐1 post two cycle (277.7 ± 181.6 ng/mL) and EOT (403.9 ± 218.9 ng/mL) were significantly elevated compared to baseline (244.8 ± 153.8 ng/mL, p = 0.008 and p = 0.004, respectively). Early changes of sICAM‐1 (ΔsICAM‐1), deemed as sICAM‐1 after two cycles minus baseline, were assessed. Following ICI treatments, responders had significantly lower ΔsICAM‐1 compared with nonresponders in the primary cohort (p = 0.040) and the validation cohort (p = 0.026). High ΔsICAM‐1 was strongly associated with inferior progression‐free survival (PFS; (primary cohort: p = 0.001 and validation cohort: p = 0.002) and overall survival (OS; (primary cohort: p < 0.001 and validation cohort: p = 0.007). The ΔsICAM‐1 remained independently associated with worse PFS and OS in the primary cohort and the validation cohort. Subgroup analysis indicated patients whose sICAM‐1 significantly elevated had shorter PFS and OS in both anti‐PD‐1 and anti‐PD‐L1 treatment groups. Early change of serum sICAM‐1 could be used to monitor and predict clinical benefit of ICI therapy in patients with solid cancer.
The treatment of diffuse large B-cell lymphoma (DLBCL) is limited by the development of resistance to therapy, and there is a need to develop novel therapeutic strategies for relapsed and refractory ...aggressive lymphoma. Metformin is an oral agent for type 2 diabetes that has been shown to decrease cancer risk and lower mortality in other types of cancer.
We performed a retrospective analysis of the RPCCC database looking at patients with DLBCL treated with front-line chemotherapy. We also performed pre-clinical studies looking at the effect of metformin on cell viability, cell number, Ki67, ATP production, apoptosis, ROS production, mitochondrial membrane potential, cell cycle, effect with chemotherapeutic agents, and rituximab. Finally, we studied mouse models to see the anti-tumor effect of metformin.
Among diabetic patients, metformin use was associated with improved progression-free survival (PFS) and overall survival (OS) compared to diabetic patients not on metformin. Our pre-clinical studies showed metformin is itself capable of anti-tumor effects and causes cell cycle arrest in the G1 phase. Metformin induces apoptosis, ROS production, and increased mitochondrial membrane permeability. Metformin exhibited additive/synergistic effects when combined with traditional chemotherapy or rituximab in vitro. In vivo, metformin in combination with rituximab showed improved survival compared with rituximab monotherapy.
Our retrospective analysis showed that metformin with front-line chemotherapy in diabetic patients resulted in improved PFS and OS. Our pre-clinical studies demonstrate metformin has potential to re-sensitize resistant lymphoma to the chemo-immunotherapy and allow us to develop a hypothesis as to its activity in DLBCL.
We studied the biological activity of pevonedistat, a first‐in‐class NEDD8‐activating enzyme (NAE) inhibitor, in combination with various cytotoxic chemotherapy agents and small molecule inhibitors ...in lymphoma preclinical models. Pevonedistat induced cell death in activated B‐cell (ABC) diffuse large B‐cell lymphoma (DLBCL) cell lines and to a lesser degree in germinal center B‐cell (GCB) DLBCL cell lines. In pevonedistat sensitive cells, we observed inhibition of NF‐κB activity by p65 co‐localization studies, decreased expression of BCL‐2/Bcl‐XL, and upregulation of BAK levels. Pevonedistat enhanced the activity of cytarabine, cisplatin, doxorubicin, and etoposide in ABC‐, but not in the GCB‐DLBCL cell lines. It also exhibited synergy with ibrutinib, selinexor, venetoclax, and A‐1331852 (a novel BCL‐XL inhibitor). In vivo, the combination of pevonedistat and ibrutinib or pevonedistat and cytarabine prolonged survival in SCID mice xenograft models when compared with monotherapy controls. Our data suggest that targeting the neddylation pathway in DLBCL is a viable therapeutic strategy and support further clinical studies of pevonedistat as a single agent or in combination with chemotherapy or novel targeted agents.
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