Upregulation of the anti-apoptotic protein MCL-1 has been implicated in chemotherapy resistance and poor clinical outcomes in B-cell lymphoma (BCL). We report the activity of AMG176, a direct, ...selective MCL-1 inhibitor, in preclinical models of BCL. A panel of cell lines representing diffuse large B-cell lymphoma (DLBCL), double-hit lymphoma (DHL) and Burkitt's lymphoma (BL) was selected. AMG176 induced apoptotic cell death in a dose- and time-dependent manner in all BCL cell lines. Baseline MCL-1 expression was not predictive of response. AMG176 exhibited impressive synergy with venetoclax and chemotherapeutic agents, less so with proteasomal inhibitors, and antagonism with anti-CD20 monoclonal antibodies. The activity of AMG176 could not be confirmed in murine models of BCL. Combination therapy targeting MCL-1 and BCL-2 may provide an alternative therapeutic approach in BCL, however optimal patient selection will remain the key to obtaining high response rates and tolerability.
Summary
The immunomodulatory drugs (IMiDs) lenalidomide and actimid (also known as CC‐4047) are thalidomide analogues which are more potent than their parental compound. In combination with ...rituximab, we have previously demonstrated that IMiDs have synergistic in vivo anti‐tumour activity in preclinical studies in a human lymphoma severe combined immunodeficiency mouse model. This report further explored the mechanisms by which IMiDs exert their anti‐lymphoma effects. Following exposure of subcutaneous lymphoma tumours in murine models to IMiDs, there was a significant increase in the recruitment of natural killer (NK) cells to tumour sites. This increase in NK cells was mediated via stimulation of dendritic cells and modification of the cytokine microenvironment associated with an increase in monocyte chemotactic protein‐1, tumour necrosis factor‐α and interferon‐γ and probably augmented rituximab‐associated antibody‐dependent cellular cytotoxicity. IMiDs also had significant anti‐angiogenic effects in our B‐cell lymphoma models. Thus, by modulation of the immune system mediated via dendritic cells and NK cells, changing the cytokine milieu, as well as by their anti‐angiogenic effects, IMiDs in combination with rituximab resulted in augmented in vivo anti‐tumour effects against B‐cell lymphoma. Our positive preclinical data adds additional support for the evaluation of IMiDs plus rituximab in patients with relapsed/refractory B‐cell lymphoma.
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.
Randomized, multicenter, open-label, phase 2/3 trial investigating lenalidomide versus investigator's choice (IC) in relapsed/refractory diffuse large B-cell lymphoma (DLBCL).
Patients with DLBCL who ...received ≥2 prior therapies were stratified by DLBCL subtype germinal center B-cell (GCB) vs. non-GCB; determined by immunohistochemistry (IHC) and then randomized 1:1 to lenalidomide (25 mg/day, 21 days of 28-day cycle) or IC (gemcitabine, rituximab, etoposide, or oxaliplatin). Crossover to lenalidomide was permitted for IC-treated patients with radiologically confirmed progressive disease. The primary endpoint was overall response rate (ORR). Progression-free survival (PFS), overall survival, and subtype analysis GCB vs. activated B-cell (ABC) using gene expression profiling (GEP) were exploratory endpoints.
Stage 1: 102 DLBCL patients (by IHC: non-GCB,
= 54; GCB,
= 48) received ≥1 dose of lenalidomide or IC. Hematologic treatment-emergent adverse events with lenalidomide versus IC included neutropenia (42.6%; 36.4%), anemia (33.3%; 47.3%), thrombocytopenia (24.1%; 43.6%), and leukopenia (5.6%; 12.7%), respectively. Overall, lenalidomide-treated patients had an ORR of 27.5% versus 11.8% in IC (ORRs were similar regardless of IHC-defined DLBCL subtype). Median PFS was increased in patients receiving lenalidomide (13.6 weeks) versus IC (7.9 weeks;
= 0.041), with greater improvements in non-GCB patients (15.1 vs. 7.1 weeks, respectively;
= 0.021) compared with GCB (10.1 vs. 9.0 weeks, respectively;
= 0.550).
The clinical benefit of lenalidomide monotherapy in DLBCL patients was more evident in the non-GCB subtype. Exploratory analyses suggest that this preferential benefit was more pronounced in the GEP-defined ABC population, demonstrating a need for additional studies of lenalidomide in DLBCL using GEP subtyping.
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Purpose
Preclinical models of chemotherapy resistance and clinical observations derived from the prospective multicenter phase III collaborative trial in relapsed aggressive lymphoma (CORAL) study ...demonstrated that primary refractory/relapsed B cell diffuse large B cell lymphoma has a poor clinical outcome with current available second-line treatments. Preclinically, we found that rituximab resistance is associated with a deregulation on the mitochondrial potential rendering lymphoma cells resistant to chemotherapy-induced apoptotic stimuli. There is a dire need to develop agents capable to execute alternative pathways of cell death in an attempt to overcome chemotherapy resistance. Posttranscriptional histone modification plays an important role in regulating gene transcription and is altered by histone acetyltransferases (HATs) and histone deacetylases (HDACs). HDACs regulate several key cellular functions, including cell proliferation, cell cycle, apoptosis, angiogenesis, migration, antigen presentation, and/or immune regulation. Given their influence in multiple regulatory pathways, HDAC inhibition is an attractive strategy to evaluate its anti-proliferation activity in cancer cells. To this end, we studied the anti-proliferation activity and mechanisms of action of suberoylanilide hydroxamic acid (SAHA, vorinostat) in rituximab–chemotherapy-resistant preclinical models.
Methods
A panel of rituximab–chemotherapy-sensitive (RSCL) and rituximab–chemotherapy-resistant cell lines (RRCL) and primary tumor cells isolated from relapsed/refractory B cell lymphoma patients were exposed to escalating doses of vorinostat. Changes in mitochondrial potential, ATP synthesis, and cell cycle distribution were determined by Alamar blue reduction, Titer-Glo luminescent assays, and flow cytometric, respectively. Protein lysates were isolated from vorinostat-exposed cells, and changes in members of Bcl-2 family, cell cycle regulatory proteins, and the acetylation status of histone H3 were evaluated by Western blotting. Finally, cell lines were pre-exposed to vorinostat for 48 h and subsequently exposed to several chemotherapy agents (cisplatin, etoposide, or gemcitabine); changes in cell viability were determined by CellTiter-Glo
®
luminescence assay (Promega, Fitchburg, WI), and synergistic activity was evaluated using the CalcuSyn software.
Results
Vorinostat induced dose-dependent cell death in RRCL and in primary tumor cells. In addition, in vitro exposure of RRCL to vorinostat resulted in an increase in p21 and acetylation of histone H3 leading to G1 cell cycle arrest. Vorinostat exposure resulted in apoptosis in RSCL cell lines but not in RRCL. This finding suggests that in RRCL, vorinostat induces cell death by alternative pathways (i.e., irreversible cell cycle arrest). Of interest, vorinostat was found to reverse acquired chemotherapy resistance in RRCL.
Conclusions
Our data suggest that vorinostat is active in RRCL with a known defective apoptotic machinery, it can active alternative cell death pathways. Given the multiple pathways affected by HDAC inhibition, vorinostat can potentially be used to overcome acquired resistant to chemotherapy in aggressive B cell lymphoma.
•Liso-cel significantly improved EFS, CR rate, and PFS vs chemotherapy ± ASCT as a second-line treatment for LBCL.•Liso-cel was well tolerated as a second-line therapy, with low rates of any grade or ...severe cytokine release syndrome and neurological events.
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This global phase 3 study compared lisocabtagene maraleucel (liso-cel) with a standard of care (SOC) as second-line therapy for primary refractory or early relapsed (≤12 months) large B-cell lymphoma (LBCL). Adults eligible for autologous stem cell transplantation (ASCT; N = 184) were randomly assigned in a 1:1 ratio to liso-cel (100 × 106 chimeric antigen receptor–positive T cells) or SOC (3 cycles of platinum-based immunochemotherapy followed by high-dose chemotherapy and ASCT in responders). The primary end point was event-free survival (EFS). In this primary analysis with a 17.5-month median follow-up, median EFS was not reached (NR) for liso-cel vs 2.4 months for SOC. Complete response (CR) rate was 74% for liso-cel vs 43% for SOC (P < .0001) and median progression-free survival (PFS) was NR for liso-cel vs 6.2 months for SOC (hazard ratio HR = 0.400; P < .0001). Median overall survival (OS) was NR for liso-cel vs 29.9 months for SOC (HR = 0.724; P = .0987). When adjusted for crossover from SOC to liso-cel, 18-month OS rates were 73% for liso-cel and 54% for SOC (HR = 0.415). Grade 3 cytokine release syndrome and neurological events occurred in 1% and 4% of patients in the liso-cel arm, respectively (no grade 4 or 5 events). These data show significant improvements in EFS, CR rate, and PFS for liso-cel compared with SOC and support liso-cel as a preferred second-line treatment compared with SOC in patients with primary refractory or early relapsed LBCL. This trial was registered at www.clinicaltrials.gov as #NCT03575351.
Abramson and colleagues report on the primary analysis of the TRANSFORM study, a randomized trial of lisocabtagene maraleucel (liso-cel) following a cycle of bridging therapy (if needed) vs standard-of-care salvage chemotherapy and autologous transplantation in second-line therapy of patients with primary refractory or early relapse large B-cell lymphoma. Liso-cel significantly improves event-free survival as well as complete response rate and progression-free survival but not overall survival after a median of 18 months follow-up. These data establish liso-cel as a standard of care for these patients with a previous poor prognosis.
Acquirement of resistance to rituximab has been observed in lymphoma patients. To define mechanisms associated with rituximab resistance, we developed various rituximab-resistant cell lines (RRCL) ...and studied changes in CD20 expression/structure, lipid raft domain (LRD) reorganization, calcium mobilization, antibody-dependent cellular cytotoxicity, and complement-mediated cytotoxicity (CMC) between parental and RRCL. Significant changes in surface CD20 antigen expression were shown in RRCL. Decreased calcium mobilization and redistribution of CD20 into LRD were found in RRCL. Western blotting identified a unique 35 kDa protein band in RRCL, which was not seen in parental cells and was secondary to an increase in surface and cytoplasmic expression of IgM light chains. CD20 gene expression was decreased in RRCL. In vitro exposure to PS341 increased CD20 expression in RRCL and minimally improved the sensitivity to rituximab-associated CMC. Our data strongly suggest that the acquisition of rituximab resistance is associated with global gene and protein down-regulation of the CD20 antigen affecting LRD organization and downstream signaling. CD20 expression seems to be regulated at the pretranscriptional and posttranscriptional levels. Proteasome inhibition partially reversed rituximab resistance, suggesting the existence of additional mediators of rituximab resistance. Future research is geared to identify drugs and/or biological agents that are effective against RRCL.
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