Current trials for frontline therapy of mantle cell lymphoma

Advances in the treatment of mantle cell lymphoma with BTK inhibitors

Mantle cell lymphoma (MCL) is a heterogenous disease that is one of the most challenging blood cancers due to its poor prognosis, high risk of relapse and drug resistance. Recent researches have brought significant changes in MCL patients outcomes and new clinical. Bruton's Tyrosine Kinase (BTK), a key kinase in the B-cell antigen receptor (BCR) signaling pathway, is a clinical research hot spot and plays a major role in the survival and spread of malignant B cells. The first generation of BTK inhibitors, led by ibrutinib, have shown promising results in targeted treatment. Meanwhile, several inhibitors have entered clinical studies and demonstrated outstanding therapeutic activity in clinical trials for MCL, indicating a good prospect for development. Despite these encouraging findings, the duration of response is limited, and resistance to BTK inhibitors develops in a portion of individuals. This review summarizes the pathogenesis of MCL and targeted BTK inhibitors and provides an overview of the mutations that can lead to resistance to BTK inhibitors. The purpose of this article is to review the literature describing these selective therapies and provides perspectives for their further development.

Long-term outcome in patients with mantle cell lymphoma following high-dose therapy and autologous stem cell transplantation

BACKGROUND

Long-term clinical and molecular remissions in patients with mantle cell lymphoma (MCL) after autologous stem cell transplantation (ASCT) have been evaluated in only a few studies.

DESIGN AND METHODS

Sixty-five patients with MCL received ASCT (54 first-line ASCT, 10 second-line ASCT, and 1 third-line ASCT). In the case of long-term remission (≥5 years; n = 27), peripheral blood was tested for minimal residual disease (MRD) by t(11;14)- and IGH-PCR at the last follow-up.

RESULTS

Ten-year overall survival (OS), progression-free survival (PFS), and freedom from progression (FFP) after first-line ASCT were 64%, 52%, and 59% versus after second-line ASCT 50%, 20%, and 20%, respectively. Five-year OS, PFS, and FFP for the first-line cohort were 79%, 63%, and 69%, respectively. Five-year OS, PFS, and FFP after second-line ASCT were 60%, 30%, and 30%, respectively. Treatment-related mortality (3 months after ASCT) was 1.5%. So far 26 patients developed sustained long-term clinical and molecular complete remissions of up to 19 years following ASCT in first treatment line.

CONCLUSION

Sustained long-term clinical and molecular remissions are achievable following ASCT.

Exploiting PRMT5 as a target for combination therapy in mantle cell lymphoma characterized by frequent ATM and TP53 mutations

Constant challenges for the treatment of mantle cell lymphoma (MCL) remain to be recurrent relapses and therapy resistance, especially in patients harboring somatic mutations in the tumor suppressors ATM and TP53, which are accumulated as therapy resistance emerges and the disease progresses, consistent with our OncoPrint results that ATM and TP53 alterations were most frequent in relapsed/refractory (R/R) MCL. We demonstrated that protein arginine methyltransferase-5 (PRMT5) was upregulated in R/R MCL, which predicted a poor prognosis. PRMT5 inhibitors displayed profound antitumor effects in the mouse models of MCL with mutated ATM and/or TP53, or refractory to CD19-targeted CAR T-cell therapy. Genetic knockout of PRMT5 robustly inhibited tumor growth in vivo. Co-targeting PRMT5, and ATR or CDK4 by using their inhibitors showed synergistic antitumor effects both in vitro and in vivo. Our results have provided a rational combination therapeutic strategy targeting multiple PRMT5-coordinated tumor-promoting processes for the treatment of R/R MCL with high mutation burdens.

3-Methyladenine but not antioxidants to overcome BACH2-mediated bortezomib resistance in mantle cell lymphoma

Background

Bortezomib (BTZ) is an inhibitor of the proteasome that has been used to treat patients with mantle cell lymphoma (MCL), but the resistance to BTZ in clinical cases remains a major drawback. BACH2 is a lymphoid-specific transcription repressor recognized as a tumor suppressor in MCL. Reduced BACH2 levels contribute to BTZ resistance; however, the molecular events underlying BACH2-mediated BTZ resistance are largely unclear.

Methods

We silenced BACH2 in MCL cells using a lentiviral shRNA-mediated knockdown system. Bioinformatic, real-time RT-PCR, immunoblotting and a series of functional assays were performed to describe the molecular mechanisms underlying BTZ resistance in MCL. The therapeutic effects of chemicals were evaluated on numerous cellular and molecular processes in resistant MCL cell lines and xenografts.

Results

In resistant cells, BTZ-triggered mild oxidative stress induced a strong activation of PI3K-AKT signaling, which further blocked nuclear translocation of BACH2. Defective nuclear translocation of BACH2 or silencing BACH2 removed its transcriptional repression on HMOX1, leading to upregulation of heme oxygenase-1 (HO-1). Increased HO-1 further maintained reactive oxygen species (ROS) within a minimal tumor-promoting level and enhanced cytoprotective autophagy. Interestingly, although mild increase in ROS exhibited a pro-tumorigenic effect on resistant cells, simply blocking ROS by antioxidants did not lead to cell death but aggravated BTZ resistance via stabilizing BACH1, the other member of BACH family. Instead, 3-methyladenine (3-MA), a dual inhibitor to suppress PI3K signaling and autophagosome formation, sensitized resistant MCL cells to BTZ, both in vitro and in vivo.

Conclusion

Our results dissected the interconnected molecular network in resistant MCL cells in which 3-MA represents an effective therapeutic strategy to overcome BTZ resistance. Notably, BACH1 and BACH2, albeit from the same family, are likely to play opposite roles in pathogenesis and progression of MCL.

BAFF receptor antibody for mantle cell lymphoma therapy

Mantle cell lymphoma (MCL) is an aggressive form of B cell non-Hodgkin’s lymphoma and remains incurable under current treatment modalities. One of the main reasons for treatment failure is the development of drug resistance. Accumulating evidence suggests that B cell activating factor (BAFF) and BAFF receptor (BAFF-R) play an important role in the proliferation and survival of malignant B cells. High serum BAFF levels are often correlated with poor drug response and relapse in MCL patients. Our study shows that BAFF-R is expressed on both MCL patient cells and cell lines. BAFF-R knockdown leads to MCL cell death showing the importance of BAFF-R signaling in MCL survival. Moderate knockdown of BAFF-R in MCL cells did not affect its viability, but sensitized them to cytarabine treatment in vitro and in vivo, with prolonged mice survival. Anti-BAFF-R antibody treatment promoted drug-induced MCL cell death. Conversely, the addition of recombinant BAFF (rhBAFF) to MCL cells protected them from cytarabine-induced apoptosis. We tested the efficacy of a humanized defucosylated ADCC optimized anti-BAFF-R antibody in killing MCL. Our data show both in vitro and in vivo efficacy of this antibody for MCL therapy. To conclude, our data indicate that BAFF/BAFF-R signaling is crucial for survival and involved in drug resistance of MCL. Targeting BAFF-R using BAFF-R antibody might be a promising therapeutical strategy to treat MCL patients resistant to chemotherapy.

Drug resistance and Cancer stem cells

Therapy resistance is a major problem when treating cancer patients as cancer cells develop mechanisms that counteract the effect of therapeutic compounds, leading to fit and more aggressive clones that contribute to poor prognosis. Therapy resistance can be both intrinsic and/or acquired. These are multifactorial events, and some are related to factors including adaptations in cancer stem cells (CSCs), epithelial-mesenchymal transition (EMT), deregulation of key signaling pathways, drug efflux through ABC transporters, acquired mutations, evading apoptosis, and activation of DNA damage response among others. Among these factors, CSCs represent the major source of therapy resistance. CSCs are a subset of tumor cells that are capable of self-renewal and multilineage progenitor expansion that are known to be intrinsically resistant to anticancer treatments. Multiple clones of CSCs pre-exist, and some can adopt and expand easily to changes in the tumor microenvironment (TME) and/or in response to radio- and chemotherapy. A combination of both intrinsic and extrinsic factors contributes to CSC-mediated therapy resistance. In this review, we will focus on CSCs and therapy resistance as well as suggest strategies to eliminate CSCs and, therefore, overcome resistance. Video abstract.

Drug Repurposing Screen Identifies Novel Classes of Drugs with Anticancer Activity in Mantle Cell Lymphoma

AIM AND OBJECTIVE

Mantle Cell Lymphoma (MCL) is typically an aggressive and rare disease with poor prognosis, therefore new effective therapeutics are urgently needed. Drug repurposing for cancer treatment is becoming increasingly more attractive as an alternative approach to discover clinically approved drugs that demonstrate antineoplastic effect. The objective of this study was to screen an approved drug library and identify candidate compounds with an antineoplastic effect in MCL cells using High-Throughput Screening (HTS) technique.

MATERIALS AND METHODS

Using the HTS technique, nearly 3,800 clinically approved drugs and drug candidates were screened in Jeko and Mino MCL cell lines. We also demonstrated the selectivity window of the candidate compounds in six normal cell lines. Further validations were performed in caspase-3/7 apoptosis assay and three-dimensional (3D) multicellular aggregates model using Z138 cell line.

RESULTS

We identified 98 compounds showing >50% inhibition in either MCL cell line screened, they were distributed across eight unique therapeutic categories and have different mechanisms of action (MOA). We selected alisertib, carfilzomib, pracinostat and YM155 for further validation based on their antiproliferative activity in two MCL cell lines, selectivity to normal cell lines, and drug developing stages in terms of clinical research. Alisertib and carfilzomib showed antiproliferative effect on MCL cell with EC50 = 6 nM and >100-fold selectivity to normal cell lines, especially for alisertib which demonstrated >1000-fold selectivity to 5 out of 6 normal cell lines. Pracinostat and YM155 had potency of 11 and 12 nM in MCL cell with >20-fold selectivity to normal cell lines. All four compounds had been tested in caspase-dependent apoptosis assay. We further validated and demonstrated their anti-MCL effect on cell proliferation and (3D) multicellular aggregates model using Z138 cell line.

CONCLUSION

This is the first study to examine such a large library of clinically approved compounds for the identification of novel drug candidates for MCL treatment, the results could be rapidly translated into clinical practice in patients with MCL.

Treatment patterns, adverse events, healthcare resource use and costs among commercially insured patients with mantle cell lymphoma in the United States

INTRODUCTION

There are limited data on treatment patterns, adverse events (AEs), and economic burden in younger, commercially insured patients treated for mantle cell lymphoma (MCL).

METHODS

Adults with ≥1 treatment for MCL between 1 November 2013-31 December 2017 were identified from IQVIA Real-World Data Adjudicated Claims-US; index date was first treatment. Patients carried ≥1 MCL diagnosis, were newly treated, and were enrolled continuously for ≥12 months prior to and ≥30 days following index. Patients receiving the four most common MCL regimens were included. Measures included frequency of incident AEs, resource use, and costs overall and by number of AEs. Adjusted logistic regression and generalized linear modeling evaluated risk of hospitalization and all-cause costs per patient per month (PPPM).

RESULTS

Two thousand five hundred and nine treated patients had a drug-specific code and were classified to a specific treatment regimen. Of those patients, 1785 patients received at least one of the four most commonly used MCL regimens (R-CHOP, rituximab monotherapy, B-R, and ibrutinib) at some point over follow-up (median 23 months). R-CHOP was the most common regimen observed in the first line (26%), followed by rituximab monotherapy (19%), B-R (15%), and ibrutinib (5%). The median age was 57 years; median Charlson Comorbidity Index was 0. Among patients receiving the four most common regimens, 63% of patients experienced ≥1 incident AE (R-CHOP 77%, B-R 58%, and ibrutinib 52%). An increasing number of incident AEs was associated with increased hospitalization risk (odds ratio = 2.4; 95% Confidence Interval [CI] 2.1-2.7) and increased mean costs PPPM (cost ratio = 1.1; 95% CI 1.1-1.2).

DISCUSSION

This is the largest study describing treatment patterns and clinical and economic impact of MCL treatment. The most common regimens were R-CHOP, rituximab monotherapy, B-R, and ibrutinib. The majority of treated patients experienced at least one incident AE, with hospitalization risk and all-cause costs increasing as the number of AEs increased.

Antibody-drug conjugates in clinical trials for lymphoid malignancies and multiple myeloma

Antibody-drug conjugates (ADC) represent a distinct family of chemoimmunotherapy agents. ADCs are composed of monoclonal antibodies conjugated to cytotoxic payloads via specialized chemical linkers. ADCs therefore combine the immune therapy with targeted chemotherapy. Due to the distinct biomarkers associated with lymphocytes and plasma cells, ADCs have emerged as a promising treatment option for lymphoid malignancies and multiple myeloma. Several ADCs have been approved for clinical applications: brentuximab vedotin, inotuzumab ozogamicin, moxetumomab pasudotox, and polatuzumab vedotin. More novel ADCs are under clinical development. In this article, we summarized the general principles for ADC design, and updated novel ADCs under various stages of clinical trials for lymphoid malignancies and multiple myeloma.

Cyclin D1 + large B-cell lymphoma with altered CCND1 and BCL-6 rearrangements: a diagnostic challenge

Background

A subset of diffuse large B-cell lymphoma may show aberrant cyclin D1 expression, which may be confused with blastoid mantle cell lymphoma. These cases usually lack of CCND1 gene rearrangement. Duplication of CCND1 gene was attributed to some of the cases with cyclin D1 expression. The mechanism of overexpression of CCND1 in other cases was not well documented.

Case presentation

We report a case of diffuse large B-cell lymphoma with cyclin D1 expression. The underlying mechanism for cyclin D1 expression was due to an abnormal gene rearrangement involving BCL-6 and CCND1, which was different from most reported cases. Rare cases with similar genetic profile were reported and were classified as diffuse large B-cell lymphoma.

Conclusion

The phenotype and genetic abnormalities of DLBCL with cyclin D1 overexpression can be complex and may be difficult to differentiate from blastoid and pleomorphic variants of mantle cell lymphoma.

Gastrointestinal Perforation after Rituximab Therapy in Mantle Cell Lymphoma: A Case Report

Mantle cell lymphoma (MCL) is a rare form of non-Hodgkin lymphoma (NHL), responsible for 2.8% of all NHL cases within the United States. The majority of patients with MCL present with advanced disease, 10–20% of which have extra-nodal involvement at diagnosis. The gastrointestinal presence of lymphoma can lead to gastrointestinal perforation, resulting in significant morbidity from peritonitis and sepsis while prolonging hospitalizations and delaying treatment. In this case we discuss a 55-year-old male with newly diagnosed MCL who developed peritonitis 9 days after initiation of dose reduced rituximab due to gastrointestinal perforation. Although prognostication factors for MCL such as the mantle cell lymphoma international prognostic index (MIPI) score exist, further research is needed to stratify risk factors for morbid treatment complications such as gastrointestinal perforation.

Identification of MMP9 as a novel key gene in mantle cell lymphoma based on bioinformatic analysis and design of cyclic peptides as MMP9 inhibitors based on molecular docking

Mantle cell lymphoma (MCL) is an aggressive disease. MCL is associated with poor patient prognosis and limited survival. To identify key genes and explore targeting cyclic peptide inhibitors for the treatment of MCL, we downloaded two gene expression profiles (GSE32018 and GSE9327) from the Gene Expression Omnibus (GEO) database. We screened 84 differentially expressed genes (DEGs). Pathway analysis showed that DEMs were mainly enriched in the ‘Pathway in cancer’, ‘PI3K-Akt signaling pathway’, ‘Cytokine-cytokine receptor interaction’, ‘Rap1 signaling pathway’, ‘NF-κB signaling pathway’ and ‘Leukocyte trans-endothelial migration’. We subsequently constructed a protein-protein interaction (PPI) network of DEGs. In addition, matrix metalloproteinase 9 (MMP9) with a high degree in the PPI network was identified as a hub gene in MCL. Meanwhile in the Molecular Complex Detection (MCODE) analysis, MMP9 was located in the important cluster. Thus, MMP9 can be used as a therapeutic target for MCL and we designed cyclic peptides as MMP9 inhibitors. MMP9 protein structure was gathered from the Protein Data Bank (PDB), with a PDB ID: 1L6J. MMP9 and cyclic peptides were docked using Molecular Operating Environment (MOE) software after structural optimization. It was revealed that cyclic peptide 2 bound deeply in the binding pocket of MMP9 and had interaction with the active-site Zn²⁺ ion in the catalytic domain. Cyclic peptides 1, 2, 4–6 also displayed potential interaction with active residues of MMP9; thus, these cyclic peptides can serve as potential drug candidates to block MMP9 activity and future studies are warranted to confirm their efficacy.