Mantle cell lymphoma (MCL) is characterized by an aggressive clinical course and inevitable development of refractory disease, stressing the need to develop alternative therapeutic strategies. To ...this end, we evaluated pevonedistat (MLN4924), a novel potent and selective NEDD8-activating enzyme inhibitor in a panel of MCL cell lines, primary MCL tumor cells, and 2 distinct murine models of human MCL. Pevonedistat exposure resulted in a dose-, time-, and caspase-dependent cell death in the majority of the MCL cell lines and primary tumor cells tested. Of interest, in the MCL cell lines with lower half-maximal inhibitory concentration (0.1-0.5 μM), pevonedistat induced G1-phase cell cycle arrest, downregulation of Bcl-xL levels, decreased nuclear factor (NF)-κB activity, and apoptosis. In addition, pevonedistat exhibited additive/synergistic effects when combined with cytarabine, bendamustine, or rituximab. In vivo, as a single agent, pevonedistat prolonged the survival of 2 MCL-bearing mouse models when compared with controls. Pevonedistat in combination with rituximab led to improved survival compared with rituximab or pevonedistat monotherapy. Our data suggest that pevonedistat has significant activity in MCL preclinical models, possibly related to effects on NF-κB activity, Bcl-xL downregulation, and G1 cell cycle arrest. Our findings support further investigation of pevonedistat with or without rituximab in the treatment of MCL.
•Pevonedistat (MLN4924), a NEDD8-activating enzyme inhibitor, is active in MCL preclinical models and potentiates rituximab activity.•Our findings support further investigation of pevonedistat with or without rituximab in the treatment of MCL.
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.
Despite major advances in the treatment of non-Hodgkin lymphoma (NHL), including the use of chemotherapeutic agents and the anti-CD20 antibody rituximab, the majority of patients eventually relapse, ...and salvage treatments with non–cross-resistant compounds are needed to further improve patient survival. Here, we evaluated the antitumor effects of the microtubule destabilizing agent monomethyl auristatin E (MMAE) conjugated to the humanized anti-CD19 antibody hBU12 via a protease-sensitive valine-citrulline (vc) dipeptide linker. hBU12-vcMMAE induced potent tumor cell killing against rituximab-sensitive and -resistant NHL cell lines. CD19 can form heterodimers with CD21, and high levels of CD21 were reported to interfere negatively with the activity of CD19-targeted therapeutics. However, we observed comparable internalization, intracellular trafficking, and drug release in CD21low and CD21high, rituximab-sensitive and -refractory lymphomas treated with hBU12-vcMMAE. Furthermore, high rates of durable regressions in mice implanted with these tumors were observed, suggesting that both rituximab resistance and CD21 expression levels do not impact on the activity of hBU12-vcMMAE. Combined, our data suggest that hBU12-vcMMAE may represent a promising addition to the treatment options for rituximab refractory NHL and other hematologic malignancies, including acute lymphoblastic leukemia.
Intercellular adhesion molecule-1 (ICAM-1) is a cell-surface receptor contributing to lymphocyte homing, adhesion and activation. The prognostic significance of the protein is unknown in diffuse ...large B-cell lymphoma (DLBCL) in post-rituximab era. We detected expression of ICAM-1 immunohistochemically in 102 DLBCL tissue samples. Overexpression of ICAM-1 was found in 28 (27.5%) cases. In patients with low ICAM-1 expression levels, the addition of rituximab to CHOP (cyclophosphamide, doxorubicin, vincristine and prednisone) chemotherapy resulted in an improved overall response rate, progression-free survival (PFS) and overall survival (OS) (
=0.019, 0.01, 0.02). In pre-clinical models, we found that chronic exposure of cell lines to rituximab led to downregulation of ICAM-1 and acquirement of a rituximab resistant phenotype. In vitro exposure of rituximab resulted in rapid aggregation of B-cells regardless of the ICAM-1 expression levels. MTT assay showed knockdown of ICAM-1 could cause rituximab resistance. Neutralization of ICAM-1 did not affect rituximab activity in vitro and in vivo. Our data illustrated that in post-rituximab era, R-CHOP significantly improved the ORR, PFS and OS in ICAM-1 negative subset patients. Downregulation of ICAM-1 may contribute to rituximab resistance, and that rituximab, by promoting cell-cell aggregation, may sensitize cells to the cytotoxic effects of chemotherapy agents.
Preclinical data demonstrated that combining an anti–programmed cell death 1 (PD-1) inhibitor with a cyclin-dependent kinase 9 (CDK9) inhibitor provided enhanced antitumor activity with no ...significant toxicities, suggesting this combination may be a potential therapeutic option. The multicohort, phase 1 KEYNOTE-155 study evaluated the safety and antitumor activity of the PD-1 inhibitor pembrolizumab plus the CDK9 inhibitor dinaciclib in patients with relapsed or refractory (rr) chronic lymphocytic leukemia (CLL), diffuse large B-cell lymphoma (DLBCL) and multiple myeloma (MM). Patients enrolled were ≥18 years of age with a confirmed diagnosis of CLL, DLBCL, or MM. The study included 2 phases: a dose-evaluation phase to determine dose-limiting toxicities and a signal-detection phase. Patients received pembrolizumab 200 mg every 3 weeks plus dinaciclib 7 mg/m2 on day 1 and 10 mg/m2 on day 8 of cycle 1 and 14 mg/m2 on days 1 and 8 of cycles 2 and later. Primary endpoint was safety, and a key secondary endpoint was objective response rate (ORR). Seventy-two patients were enrolled and received ≥1 dose of study treatment (CLL, n = 17; DLBCL, n = 38; MM, n = 17). Pembrolizumab plus dinaciclib was generally well tolerated and produced no unexpected toxicities. The ORRs were 29.4% (5/17, rrCLL), 21.1% (8/38, rrDLBCL), and 0% (0/17, rrMM), respectively. At data cutoff, all 72 patients had discontinued treatment, 38 (52.8%) because of progressive disease. These findings demonstrate activity with combination pembrolizumab plus dinaciclib and suggest that a careful and comprehensive approach to explore anti–PD-1 and CDK9 inhibitor combinations is warranted. This trial was registered at www.clinicaltrials.gov as NCT02684617.
•Treatment with pembrolizumab plus dinaciclib resulted in antitumor activity with acceptable safety for patients with rrCLL and rrDLBCL.•A careful and comprehensive approach to explore PD-1 inhibition and CDK9 inhibition in combination with other agents is needed.
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Classical Hodgkin lymphoma treatment is evolving rapidly with high response rates from antibody-drug conjugates targeting CD30 and immune checkpoint antibodies. However, most patients do not achieve ...a complete response, therefore development of novel therapies is warranted to improve patient outcomes. In this phase II study, patients with relapsed or refractory Hodgkin lymphoma were treated with entinostat, an isoform selective histone deacetylase inhibitor. Forty-nine patients were enrolled: 33 patients on Schedule A (10 or 15 mg oral entinostat once every other week); 16 patients on Schedule B (15 mg oral entinostat once weekly in 3 of 4 weeks). Patients received a median of 3 prior treatments (range 1-10), with 80% of the patients receiving a prior stem cell transplant and 8% of patients receiving prior brentuximab vedotin. In the intention-to-treat analysis, the overall response rate was 12% while the disease control rate (complete response, partial response, and stable disease beyond 6 months) was 24%. Seven patients did not complete the first cycle due to progression of disease. Tumor reduction was observed in 24 of 38 (58%) evaluable patients. Median progression-free survival and overall survival was 5.5 and 25.1 months, respectively. The most frequent grade 3 or 4 adverse events were thrombocytopenia (63%), anemia (47%), neutropenia (41%), leukopenia (10%), hypokalemia (8%), and hypophosphatemia (6%). Twenty-five (51%) patients required dose reductions or delays. Pericarditis/pericardial effusion occurred in one patient after 12 cycles of therapy. Future studies are warranted to identify predictive biomarkers for treatment response and to develop mechanism-based combination strategies. (clinicaltrials.gov identifier: 00866333).
Clinical observations suggest the existence of shared resistance pathways between rituximab and chemotherapy agents. To explore the mechanisms of rituximab resistance, our group created ...rituximab-resistant cell lines (RRCLs), which display altered expression of several inhibitor of apoptosis (IAP) family proteins. Here, we provide evidence to support pharmacologically targeting IAPs in lymphoma with LCL-161, a small molecule mimetic of the second mitochondria-derived activator of caspases (SMAC). The antitumor effect of LCL-161 was determined using luminescent adenosine triphosphate assays, flow cytometry, SCID mouse xenografts, and ex vivo patient biopsy sample studies. In vitro exposure to LCL-161 also resulted in a dose-dependent decrease in IAP levels, along with synergistic enhancement of the antitumor effect of cytotoxic chemotherapy, in rituximab-sensitive cell lines and RRCLs. In addition, LCL-161 increased the cytotoxic effect of the proteasome inhibitor carfilzomib in ex vivo lymphoma patient samples. The combination of LCL-161 with the chemotherapy regimen rituximab, gemcitabine, and vinorelbine (RGV) improved in vivo survival compared with RGV alone in severe combined immunodeficient mice implanted with RRCLs but not in animals implanted with rituximab-sensitive cell lines. In summary, LCL-161 exhibits synergistic antitumor activity in both in vitro and in vivo models of resistant lymphoma. Our data support further preclinical investigation of LCL-161 as a novel antilymphoma agent.
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