[Inhibition of Autophagy Augments the Anticancer Activity of KPT-330 in Mantle Cell Lymphoma Cells].

OBJECTIVE: To investigate the influence of novel CRM1 inhibitor KPT-330 on the autophagy of mantle cell lymphoma (MCL) cells, and effect of KPT-330 on the prolifiration of MCL cells in the presence or absence of autophagy inhibitor. METHODS: CCK-8 assay was used to detect the effect of KPT-330 on MCL cell lines Z-138， Jeko-1， Granta-519， Rec-1. The effect of KPT-330 on autophagy features were determined by detecting acidic vesicular organelles (AVO) by MDC staining under fluorescence microscope and detecting protein expression of LC3B-II assessed by Western blot. Further combined application of lysosomal inhibitor Chloroquine (CQ) was used to observe its effect on the increase of LC3B-Ⅱ caused by KPT-330. CalcuSyn 2.0 software was used to detected the Combination index (CI) of KPT-330 combined with CQ. RESULTS: The proliferation of MCL cell lines （Z-138, Jeko-1, Grant-519, Rec-1） could be inhibited by KPT-330 in a dose-dependent manner (r =0.930, 0.946, 0.691, 0.968 respectively). The number of acidic vesicular organelles (AVO) and the expression of LC3B-II were increased in KPT-330 treated Jeko-1 and Granta-519 cells in a dose-dependent manner (r Jeko-1=0.993, r Granta-519=0.971). LC3B-II protein amounts still increased upon KPT-330 treatment with the existence of lysosomal inhibitor CQ in Jeko-1 and Granta-519 cells, which was higher than CQ or KPT-330 single drug group. The combination of KPT-330 and CQ produced the synergistic effects on cells proliferation inhibition with CalcuSyn 2.0 analysis. CONCLUSION: KPT-330 can inhibit MCL cell proliferation and induce autophagy. KPT-330 combined with autophagy inhibitor CQ could produce synergistic anti MCL effects, providing experimental basis for clinical combination therapy.

SOX11/PRDX2 axis modulates redox homeostasis and chemoresistance in aggressive mantle cell lymphoma.

Mantle cell lymphoma (MCL) is an incurable B-cell neoplasm characterized by an aggressive behavior, short responses to conventional therapies and SOX11 overexpression, which is associated with aggressive disease features and inferior clinical outcome of patients. Oxidative stress is known to induce tumorigenesis and tumor progression, whereas high expression levels of antioxidant genes have been associated with chemoresistance in different cancers. However, the role of oxidative stress in MCL pathogenesis and the involvement of SOX11 regulating redox homeostasis in MCL cells are largely unknown. Here, by integrating gene set enrichment analysis of two independent series of MCL, we observed that SOX11+ MCL had higher reactive oxygen species (ROS) levels compared to SOX11- MCL primary tumors and increased expression of Peredoxine2 (PRDX2), which upregulation significantly correlated with SOX11 overexpression, higher ROS production and worse overall survival of patients. SOX11 knockout (SOX11KO) significantly reduced PRDX2 expression, and SOX11KO and PRDX2 knockdown (PRDX2KD) had increased ROS levels and ROS-mediated tumor cell death upon treatment with drugs, compared to control MCL cell lines. Our results suggest an aberrant redox homeostasis associated with chemoresistance in aggressive MCL through SOX11-mediated PRDX2 upregulation, highlighting PRDX2 as promising target for new therapeutic strategies to overcome chemoresistance in aggressive MCLs.

Targeting DNMT3A-mediated oxidative phosphorylation to overcome ibrutinib resistance in mantle cell lymphoma.

The use of Bruton tyrosine kinase (BTK) inhibitors such as ibrutinib achieves a remarkable clinical response in mantle cell lymphoma (MCL). Acquired drug resistance, however, is significant and affects long-term survival of MCL patients. Here, we demonstrate that DNA methyltransferase 3A (DNMT3A) is involved in ibrutinib resistance. We find that DNMT3A expression is upregulated upon ibrutinib treatment in ibrutinib-resistant MCL cells. Genetic and pharmacological analyses reveal that DNMT3A mediates ibrutinib resistance independent of its DNA-methylation function. Mechanistically, DNMT3A induces the expression of MYC target genes through interaction with the transcription factors MEF2B and MYC, thus mediating metabolic reprogramming to oxidative phosphorylation (OXPHOS). Targeting DNMT3A with low-dose decitabine inhibits the growth of ibrutinib-resistant lymphoma cells both in vitro and in a patient-derived xenograft mouse model. These findings suggest that targeting DNMT3A-mediated metabolic reprogramming to OXPHOS with decitabine provides a potential therapeutic strategy to overcome ibrutinib resistance in relapsed/refractory MCL.

[Efficacy and Prognosis of Chemotherapy Regimen Containing BTK Inhibitor in Treatment of Recurrent/Refractory Mantle Cell Lymphoma].

OBJECTIVE: To investigate the efficacy and prognosis of chemotherapy regimen containing Bruton's tyrosine kinase (BTK) inhibitor in the treatment of relapsed/refractory mantle cell lymphoma (R/R MCL). METHODS: The clinical data of 134 patients with R/R MCL were collected and analyzed retrospectively. The clinical characteristics of patients and effect of chemotherapy regimen on efficacy, overall survival (OS) and progression-free survival (PFS) were observed. RESULTS: The median age of the patients was 58(56-61) years old, and male to female ratio was about 2.9∶1. Patients with Ann Arbor stage III-IV accounted for 77.6%, extranodal involvement > 2 for 43.3%, bone marrow involvement for 60.4%, gastrointestinal involvement for 24.6%, and hepatosplenomegaly for 38.1%. The median follow-up time was 30 (2-103) months, overall response rate (ORR) was 41.8%, 3-year PFS was not reached, and 3-year and 5-year OS rate was 62.7% and 53.8%, respectively. The ORR of BTK inhibitor group was 56.9%, which was higher than 32.5% of non-BTK inhibitor group (P =0.006). The difference was statistically significant in PFS between the two groups (P =0.002), but was not in OS (P>0.05). The difference was statistically significant in OS between classical and special morphology (P < 0.001), but was not in PFS (P >0.05). Ki-67 was an influencing factor for OS and PFS. Multivariate analysis showed that Ki-67, B symptoms, MIPI score, and Ann Arbor stage were independent prognostic factors affecting patients' OS. The second-line treatment regimen was an independent prognostic factor affecting patients' PFS. CONCLUSIONS: The chemotherapy regimen containing BTK inhibitors can effectively improve the efficacy and prolong the PFS of R/R MCL patients. Ki-67, B symptoms, MIPI score, and Ann Arbor stage are independent prognostic factors for R/R MCL patients.

[Effect of Chlorambucil Combined with Ibrutinib on Mantle Cell Lymphoma Cell Line Jeko-1 and Its Related Mechanism].

OBJECTIVE: To investigate the toxic effect of chlorambucil combined with ibrutinib on mantle cell lymphoma (MCL) cell line Jeko-1 and its related mechanism. METHODS: The MCL cell line Jeko-1 was incubated with different concentrations of chlorambucil or ibrutinib or the combination of the two drugs, respectively. CCK-8 assay was used to detect the proliferation of the cells, and Western blot was used to measure the protein expression levels of BCL-2, caspase-3, PI3K, AKT and P-AKT. RESULTS: After Jeko-1 cells were treated with chlorambucil (3.125, 6.25, 12.5, 25, 50 µmol/L) and ibrutinib (3.125, 6.25, 12.5, 25, 50 µmol /L) alone for 24, 48, 72h respectively, the cell proliferation was inhibited in a time- and dose-dependent manner. Moreover, the two drugs were applied in combination at low doses (single drug inhibition rate<50%), and the results showed that the combination of two drugs had a more significant inhibitory effect (all P < 0.05). Compared with the control group, the apoptosis rate of the single drug group of chlorambucil (3.125, 6.25, 12.5, 25, 50 µmol/L) and ibutinib (3.125, 6.25, 12.5, 25, 50 µmol/L) was increased in a dose-dependent manner. The combination of the two drugs at low concentrations (3.125, 6.25, 12.5 µmol/L) could significantly increase the apoptosis rate compared with the corresponding concentration of single drug groups (all P < 0.05). Compared with control group, the protein expression levels of caspase-3 in Jeko-1 cells were upregulated, while the protein expression levels of BCL-2, PI3K, and p-AKT/AKT were downregulated after treatment with chlorambucil or ibrutinib alone. The combination of the two drugs could produce a synergistic effect on the expressions of the above-mentioned proteins, and the differences between the combination group and the single drug groups were statistically significant (all P < 0.05). CONCLUSION: Chlorambucil and ibrutinib can promote the apoptosis of MCL cell line Jeko-1, and combined application of the two drugs shows a synergistic effect, the mechanism may be associated with the AKT-related signaling pathways.

SENP3 Promotes Mantle Cell Lymphoma Development through Regulating Wnt10a Expression.

OBJECTIVE: SUMO-specific protease 3 (SENP3), a member of the SUMO-specific protease family, reverses the SUMOylation of SUMO-2/3 conjugates. Dysregulation of SENP3 has been proven to be involved in the development of various tumors. However, its role in mantle cell lymphoma (MCL), a highly aggressive lymphoma, remains unclear. This study was aimed to elucidate the effect of SENP3 in MCL. METHODS: The expression of SENP3 in MCL cells and tissue samples was detected by RT-qPCR, Western blotting or immunohistochemistry. MCL cells with stable SENP3 knockdown were constructed using short hairpin RNAs. Cell proliferation was assessed by CCK-8 assay, and cell apoptosis was determined by flow cytometry. mRNA sequencing (mRNA-seq) was used to investigate the underlying mechanism of SENP3 knockdown on MCL development. A xenograft nude mouse model was established to evaluate the effect of SENP3 on MCL growth in vivo. RESULTS: SENP3 was upregulated in MCL patient samples and cells. Knockdown of SENP3 in MCL cells inhibited cell proliferation and promoted cell apoptosis. Meanwhile, the canonical Wnt signaling pathway and the expression of Wnt10a were suppressed after SENP3 knockdown. Furthermore, the growth of MCL cells in vivo was significantly inhibited after SENP3 knockdown in a xenograft nude mouse model. CONCLUSION: SENP3 participants in the development of MCL and may serve as a therapeutic target for MCL.

Real-world effectiveness and safety of ibrutinib in relapsed/refractory mantle cell lymphoma in Japan: post-marketing surveillance.

Efficacy and safety data for ibrutinib in Japanese patients with relapsed/refractory (R/R) mantle cell lymphoma (MCL) were limited at the time of its approval in Japan. All-case post-marketing surveillance was conducted in Japanese R/R MCL patients who began ibrutinib treatment between December 2016 and December 2017, and patients were followed until 30 June 2020. In the effectiveness analysis set (n = 202), the overall response rate was 59.9%, 52-week progression-free survival was 47.5%, and overall survival was 69.3%. Safety was assessed in 248 patients (median age 74.0 years). When ibrutinib treatment was started, patients had received a median of three prior lines of therapy. The overall incidence of adverse events (AE) was 74.6%, and AE frequency and severity grade distribution were similar between patients with 1 versus more than 1 prior line of therapy. The most common AE was platelet count decreased (all grades; 10.4%), similarly to previous observations in patients with R/R chronic lymphocytic leukemia/small lymphocytic lymphoma. Five patients (2.0%) developed atrial fibrillation. The effectiveness and safety of ibrutinib were consistent with its known profile at approval in Japan. These results suggest that ibrutinib is effective and safe in Japanese R/R MCL patients in routine clinical practice.

Indirect treatment comparison of brexucabtagene autoleucel (ZUMA-2) versus standard of care (SCHOLAR-2) in relapsed/refractory mantle cell lymphoma.

The SCHOLAR-2 retrospective study highlighted poor overall survival (OS) with standard of care (SOC) regimens among patients with relapsed/refractory (R/R) mantle cell lymphoma (MCL) who failed a covalent Bruton tyrosine kinase inhibitor (BTKi). In the ZUMA-2 single-arm trial, brexucabtagene autoleucel (brexu-cel; autologous anti-CD19 CAR T-cell therapy) demonstrated high rates of durable responses in patients with R/R MCL who had previous BTKi exposure. Here, we compared OS in ZUMA-2 and SCHOLAR-2 using three different methods which adjusted for imbalances in prognostic factors between populations: inverse probability weighting (IPW), regression adjustment (RA), and doubly robust (DR). Brexu-cel was associated with improved OS compared to SOC across all unadjusted and adjusted comparisons. Hazard ratios (95% confidence intervals) were 0.38 (0.23, 0.61) for IPW, 0.45 (0.28, 0.74) for RA, and 0.37 (0.23, 0.59) for DR. These results suggest a substantial survival benefit with brexu-cel versus SOC in patients with R/R MCL after BTKi exposure.

Death from mantle cell lymphoma limits sequential therapy, particularly after first relapse: Patterns of care and outcomes in a series from Australia and the United Kingdom.

Mantle cell lymphoma (MCL) is a B-cell non-Hodgkin lymphoma characterised by a heterogeneous clinical course. Patients can often receive sequential treatments, yet these typically yield diminishing periods of disease control, raising questions about optimal therapy sequencing. Novel agents, such as chimeric antigen receptor T-cell therapies and bispecific antibodies, show promise in relapsed MCL, but are often reserved for later treatment lines, which may underserve patients with aggressive disease phenotypes who die early in the treatment journey. To assess the problem of patient attrition from lymphoma-related death limiting sequential treatment, we performed a multicentre retrospective cohort analysis of 389 patients treated at Australian and UK centres over a 10-year period. Deaths from MCL increased after each treatment line, with 7%, 23% and 26% of patients dying from uncontrolled MCL after first, second and third lines respectively. Patients with older age at diagnosis and early relapse after induction therapy were at particular risk of death after second-line treatment. This limitation of sequential treatment by lymphoma-related death provides support for the trial of novel therapies in earlier treatment lines, particularly in high-risk patient populations.

Pirtobrutinib: A novel non-covalent BTK inhibitor for the treatment of adults with relapsed/refractory mantle cell lymphoma.

OBJECTIVE: To provide a comprehensive review of the pharmacokinetics, pharmacodynamics, safety, and efficacy of a new Food and Drug Administration (FDA) approved Bruton's tyrosine kinase inhibitor (BTKi), pirtobrutinib for relapsed/refractory mantle cell lymphoma (r/r MCL). DATA SOURCES: A literature search was conducted through PubMed MEDLINE, ClinicalTrials.gov, and the FDA website (January 2018-January 2023) using the following key terms: lymphoma, non-covalent, Bruton's tyrosine kinase (BTK), and relapse. Relevant English language monographs, studies, and abstracts conducted in humans were reviewed and considered. DATA SUMMARY: Pirtobrutinib, a novel non-covalent BTKi, was granted accelerated approval for treatment of r/r MCL on January 27th, 2023, based on an open-label, multi-center phase 1/2 BRUIN trial. In phase l, 61 patients with r/r MCL received seven dose levels of pirtobrutinib (25-300 mg). There was no reported maximum tolerated dose or dose-limiting toxicities during this study period. In phase 2, 56 r/r MCL evaluable efficacy patients received pirtobrutinib 200 mg daily. The overall response rate (ORR) was 52% (95% CI 38-65). Additionally, patients who received a previous covalent BTKi, ORR was 52% (95% CI 38-66). Neutropenia was the most common adverse reaction reported as a grade 3 or higher. CONCLUSION: Pirtobrutinib has demonstrated safety and efficacy in heavily pre-treated adult patients with r/r MCL. Advantages of this drug include its usage in patients whose malignancy is resistant to current BTKi, tolerability, and response rate. Multiple clinical trials are underway to determine the efficacy of pirtobrutinib in other B-cell malignancies.

Letting the mantle out of the bag.

Mantle cell lymphoma is a rare disease that attracts the curiosity of clinicians and scientists due to its heterogeneous clinical behaviour, that can vary from indolent forms to the most aggressive presentations among non-Hodgkin lymphomas. The report by Eyre and colleagues describes the current treatment strategies available in most countries, and offers insights to clinicians for several intriguing difficult-to-treat scenarios. Commentary on: Eyre et al. Diagnosis and management of mantle cell lymphoma: a British Society for Haematology Guideline. Br J Haematol 2024;204:108-126.

CAR T cells and time-limited ibrutinib as treatment for relapsed/refractory mantle cell lymphoma: the phase 2 TARMAC study.

ABSTRACT: CD19-directed chimeric antigen receptor T cells (CAR-T) achieve high response rates in patients with relapsed/refractory mantle cell lymphoma (MCL). However, their use is associated with significant toxicity, relapse concern, and unclear broad tractability. Preclinical and clinical data support a beneficial synergistic effect of ibrutinib on apheresis product fitness, CAR-T expansion, and toxicity. We evaluated the combination of time-limited ibrutinib and CTL019 CAR-T in 20 patients with MCL in the phase 2 TARMAC study. Ibrutinib commenced before leukapheresis and continued through CAR-T manufacture for a minimum of 6 months after CAR-T administration. The median prior lines of therapy was 2; 50% of patients were previously exposed to a Bruton tyrosine kinase inhibitor (BTKi). The primary end point was 4-month postinfusion complete response (CR) rate, and secondary end points included safety and subgroup analysis based on TP53 aberrancy. The primary end point was met; 80% of patients demonstrated CR, with 70% and 40% demonstrating measurable residual disease negativity by flow cytometry and molecular methods, respectively. At 13-month median follow-up, the estimated 12-month progression-free survival was 75% and overall survival 100%. Fifteen patients (75%) developed cytokine release syndrome; 12 (55%) with grade 1 to 2 and 3 (20%) with grade 3. Reversible grade 1 to 2 neurotoxicity was observed in 2 patients (10%). Efficacy was preserved irrespective of prior BTKi exposure or TP53 mutation. Deep responses correlated with robust CAR-T expansion and a less exhausted baseline T-cell phenotype. Overall, the safety and efficacy of the combination of BTKi and T-cell redirecting immunotherapy appears promising and merits further exploration. This trial was registered at www.ClinicalTrials.gov as #NCT04234061.

FDA Approval Summary: Pirtobrutinib for Relapsed or Refractory Mantle Cell Lymphoma.

In January 2023, the FDA granted accelerated approval to pirtobrutinib for the treatment of adult patients with relapsed or refractory mantle cell lymphoma (MCL) after at least two lines of systemic therapy, including a Bruton tyrosine kinase (BTK) inhibitor. Approval was based on BRUIN, a single-arm study of pirtobrutinib monotherapy in patients with B-cell malignancies. Efficacy was based on independent review committee-assessed overall response rate (ORR) supported by durability of response in 120 patients with relapsed or refractory MCL who had received a prior BTK inhibitor and received the approved pirtobrutinib dosage of 200 mg once daily. The ORR was 50% [95% confidence interval (CI), 41-59], and the complete response rate was 13% (95% CI, 7-20), with an estimated median duration of response of 8.3 months. The most common nonhematologic adverse reactions were fatigue, musculoskeletal pain, diarrhea, edema, dyspnea, pneumonia, and bruising. Warnings and Precautions in labeling include infection, hemorrhage, cytopenias, atrial arrhythmias, and second primary malignancies. Postmarketing studies were required to evaluate longer-term safety of pirtobrutinib and to verify the clinical benefit of pirtobrutinib. This article summarizes key aspects of the regulatory review, including the indication statement, efficacy and safety considerations, and postmarketing requirements.

Safety of bendamustine for the treatment of indolent non-Hodgkin lymphoma: a UK real-world experience.

ABSTRACT: Bendamustine is among the most effective chemotherapeutics for indolent B-cell non-Hodgkin lymphomas (iNHL), but trial reports of significant toxicity, including opportunistic infections and excess deaths, led to prescriber warnings. We conducted a multicenter observational study evaluating bendamustine toxicity in real-world practice. Patients receiving at least 1 dose of bendamustine with/without rituximab (R) for iNHL were included. Demographics, lymphoma and treatment details, and grade 3 to 5 adverse events (AEs) were analyzed and correlated. In total, 323 patients were enrolled from 9 National Health Service hospitals. Most patients (96%) received bendamustine-R, and 46%, R maintenance. Overall, 21.7% experienced serious AEs (SAE) related to treatment, including infections in 12%, with absolute risk highest during induction (63%), maintenance (20%), and follow-up (17%) and the relative risk highest during maintenance (54%), induction (34%), and follow-up (28%). Toxicity led to permanent treatment discontinuation for 13% of patients, and 2.8% died of bendamustine-related infections (n = 5), myelodysplastic syndrome (n = 3), and cardiac disease (n = 1). More SAEs per patient were reported in patients with mantle cell lymphoma, poor preinduction performance status (PS), poor premaintenance PS, and abnormal preinduction total globulins and in those receiving growth factors. Use of antimicrobial prophylaxis was variable, and 3 of 10 opportunistic infections occurred despite prophylaxis. In this real-world analysis, bendamustine-related deaths and treatment discontinuation were similar to those of trial populations of younger, fitter patients. Poor PS, mantle cell histology, and maintenance R were potential risk factors. Infections, including late onset events, were the most common treatment-related SAE and cause of death, warranting extended antimicrobial prophylaxis and infectious surveillance, especially for maintenance-treated patients.

Filgrastim-induced hemophagocytic lymphohistiocytosis in a patient with mantle cell lymphoma: A case report.

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening disease potentially induced by various causes. Very few reports have described HLH induced by granulocyte colony-stimulating factor (G-CSF) and those few previous reports have uniformly indicated that continuing G-CSF is unfeasible once HLH has been induced. A 52-year-old Japanese man who had been diagnosed with mantle cell lymphoma with systemic and central nervous system involvements received rituximab, hyper-fractionated cyclophosphamide, vincristine, Adriamycin and dexamethasone (R-HCVAD)/methotrexate and cytarabine. During the second cycle of R-HCVAD, the patient developed severe back pain, thrombocytopenia, elevated serum lactate dehydrogenase and ferritin levels, and hemophagocytosis in the bone marrow. Complete remission (CR) of mantle cell lymphoma was confirmed on whole-body computed tomography, brain magnetic resonance imaging, and bone marrow biopsy. The patient was diagnosed with HLH induced by filgrastim. HLH recovered with intravenous methylprednisolone at 1 g/day for 3 days, followed by oral prednisolone tapered off over 5 days. The patient continued chemotherapy with a change in the G-CSF formulation from filgrastim to lenograstim and prophylactic administration of corticosteroids. He safely completed scheduled chemotherapy without recurrence of HLH and successfully maintained CR of lymphoma. Although rare, G-CSF potentially induces HLH. Changing the G-CSF formulation and steroid prophylaxis may allow safe continuation of G-CSF.

Resistance to PRMT5-targeted therapy in mantle cell lymphoma.

ABSTRACT: Mantle cell lymphoma (MCL) is an incurable B-cell non-Hodgkin lymphoma, and patients who relapse on targeted therapies have poor prognosis. Protein arginine methyltransferase 5 (PRMT5), an enzyme essential for B-cell transformation, drives multiple oncogenic pathways and is overexpressed in MCL. Despite the antitumor activity of PRMT5 inhibition (PRT-382/PRT-808), drug resistance was observed in a patient-derived xenograft (PDX) MCL model. Decreased survival of mice engrafted with these PRMT5 inhibitor-resistant cells vs treatment-naive cells was observed (P = .005). MCL cell lines showed variable sensitivity to PRMT5 inhibition. Using PRT-382, cell lines were classified as sensitive (n = 4; 50% inhibitory concentration [IC50], 20-140 nM) or primary resistant (n = 4; 340-1650 nM). Prolonged culture of sensitive MCL lines with drug escalation produced PRMT5 inhibitor-resistant cell lines (n = 4; 200-500 nM). This resistant phenotype persisted after prolonged culture in the absence of drug and was observed with PRT-808. In the resistant PDX and cell line models, symmetric dimethylarginine reduction was achieved at the original PRMT5 inhibitor IC50, suggesting activation of alternative resistance pathways. Bulk RNA sequencing of resistant cell lines and PDX relative to sensitive or short-term-treated cells, respectively, highlighted shared upregulation of multiple pathways including mechanistic target of rapamycin kinase [mTOR] signaling (P < 10-5 and z score > 0.3 or < 0.3). Single-cell RNA sequencing analysis demonstrated a strong shift in global gene expression, with upregulation of mTOR signaling in resistant PDX MCL samples. Targeted blockade of mTORC1 with temsirolimus overcame the PRMT5 inhibitor-resistant phenotype, displayed therapeutic synergy in resistant MCL cell lines, and improved survival of a resistant PDX.