Lenalidomide versus investigator's choice in relapsed or refractory mantle cell lymphoma (MCL-002; SPRINT): a phase 2, randomised, multicentre trial

Glofitamab in Relapsed/Refractory Mantle Cell Lymphoma: Results From a Phase I/II Study

PURPOSE

Patients with relapsed/refractory (R/R) mantle cell lymphoma (MCL) have a poor prognosis. The phase I/II NP30179 study (ClinicalTrials.gov identifier: NCT03075696) evaluated glofitamab monotherapy in patients with R/R B-cell lymphomas, with obinutuzumab pretreatment (Gpt) to mitigate the risk of cytokine release syndrome (CRS) with glofitamab. We present data for patients with R/R MCL.

METHODS

Eligible patients with R/R MCL (at least one previous therapy) received Gpt (1,000 or 2,000 mg) 7 days before the first glofitamab dose (single dose or split over 2 days if required). Glofitamab step-up dosing was administered once a day on days 8 (2.5 mg) and 15 (10 mg) of cycle 1, with a target dose of 16 or 30 mg once every 3 weeks from cycle 2 day 1 onward, for 12 cycles. Efficacy end points included investigator-assessed complete response (CR) rate, overall response rate (ORR), and duration of CR.

RESULTS

Of 61 enrolled patients, 60 were evaluable for safety and efficacy. Patients had received a median of two previous therapies (range, 1-5). CR rate and ORR were 78.3% (95% CI, 65.8 to 87.9) and 85.0% (95% CI, 73.4 to 92.9), respectively. In patients who had received previous treatment with a Bruton tyrosine kinase inhibitor (n = 31), CR rate was 71.0% (95% CI, 52.0 to 85.8) and ORR was 74.2% (95% CI, 55.4 to 88.1). CRS after glofitamab administration occurred in 70.0% of patients, with a lower incidence in the 2,000 mg (63.6% [grade ≥2, 22.7%]) versus 1,000 mg (87.5%; grade ≥2, 62.5%) Gpt cohort. Four adverse events led to glofitamab withdrawal (all infections).

CONCLUSION

Fixed-duration glofitamab induced high CR rates in heavily pretreated patients with R/R MCL; the safety profile was manageable with appropriate support.

T-cell-based therapies for treating relapsed or refractory mantle cell lymphoma

While targeted therapies such as Bruton's tyrosine kinase and BCL2 inhibitors have fundamentally changed the treatment of mantle cell lymphoma (MCL), not all patients respond to these therapies, and responses are finite and can be fleeting, especially with high-risk MCL. As patients progress through successive therapies, the clinical course is characterized by shortening response times,1 frequent disease acceleration, and limited survival outcomes. Recently, the sensitivity of MCL to novel immune-based therapies is being realized with favorable results, as chimeric antigen receptor-modified T cells and bispecific T-cell-engaging antibodies are being investigated and implemented into practice for patients. However, critical issues remain to understand the role of these agents in routine practice. In this review, we discuss the current landscape regarding these agents, examine our approach to incorporating them into practice, and consider unanswered questions that we must ultimately address to improve outcomes for patients.

Therapeutic advances in the targeting of ROR1 in hematological cancers

Receptor tyrosine kinases (RTKs) are key cell surface receptors involved in cell communication and signal transduction, with great importance in cell growth, differentiation, survival, and metabolism. Dysregulation of RTKs, such as EGFR, VEGFR, HER2 or ROR, could lead to various diseases, particularly cancers. ROR1 has emerged as a promising target in hematological malignancies. The development of ROR1 targeted therapies is continuously growing leading to remarkable novel therapeutical approaches using mAbs, antibody-drug conjugates, several small molecules or CAR T cells which have shown encouraging preclinical results. In the hematological field, mAbs, small molecules, BiTEs or CAR T cell therapies displayed promising outcomes with the clinical trials data encouraging the use of anti-ROR1 therapies. This paper aims to offer a comprehensive analysis of the current landscape of ROR1-targeted therapies in hematological malignancies marking the innovative approaches with promising preclinical and clinical. Offering a better understanding of structural and functional aspects of ROR1 could lead to new perspectives in targeting a wide spectrum of malignancies.

Management of relapsed/refractory mantle cell lymphoma

In this review we summarize the current evidence describing the management of patients with relapsed/refractory MCL and outline the various novel therapeutics that have been developed over the past two decades. We also describe how overall response rates, complete response rates, duration of responses, and life expectancy have dramatically increased with the introduction of novel therapies, particularly covalent Bruton Tyrosine Kinase inhibitors (BTKi) and chimeric antigen receptor T-cell (CAR-T) therapy. The most recent emerging options for patients with progressive disease following BTKi or CAR-T, including non-covalent BTKi, antibody-drug conjugates, Bcl-2 inhibitors, and bispecific antibodies, may further improve response rates and outcomes. Future directions should focus on identifying the best sequencing and/or combinations of the increasingly available treatment options while prioritizing strategies with curative potential.

Biological and clinical determinants shaping heterogeneity in mantle cell lymphoma

ABSTRACT

Mantle cell lymphoma (MCL) is an uncommon mature B-cell lymphoma that presents a clinical spectrum ranging from indolent to aggressive disease, with challenges in disease management and prognostication. MCL is characterized by significant genomic instability, affecting various cellular processes, including cell cycle regulation, cell survival, DNA damage response and telomere maintenance, NOTCH and NF-κB/ B-cell receptor pathways, and chromatin modification. Recent molecular and next-generation sequencing studies unveiled a broad genetic diversity among the 2 molecular subsets, conventional MCL (cMCL) and leukemic nonnodal MCL (nnMCL), which may partially explain their clinical heterogeneity. Some asymptomatic and genetically stable nnMCL not requiring treatment at diagnosis may eventually progress clinically. Overall, the high proliferation of tumor cells, blastoid morphology, TP53 and/or CDKN2A/B inactivation, and high genetic complexity influence treatment outcome in cases treated with standard regimens. Emerging targeted and immunotherapeutic strategies are promising for refractory or relapsed cases and a few genetic and nongenetic determinants of refractoriness have been reported. This review summarizes the recent advances in MCL biology, focusing on molecular insights, prognostic markers, and novel therapeutic approaches.

Targeted Therapies in the Treatment of Mantle Cell Lymphoma

Mantle cell lymphoma (MCL) is a rare, heterogeneous B-cell non-Hodgkin's lymphoma. The standard front-line treatment utilizes chemotherapy, often followed by consolidation with an autologous hematopoietic cell transplant; however, in most patients, the lymphoma will recur and require subsequent treatments. Additionally, mantle cell lymphoma primarily affects older patients and is frequently chemotherapy-resistant, which has further fostered the necessity for new, chemotherapy-free treatment options. In the past decade, targeted therapies in mantle cell lymphoma have been practice-changing as the treatment paradigm shifts further away from relying primarily on cytotoxic agents. Here, we will review the pathophysiology of mantle cell lymphoma and discuss the emergence of targeted, chemotherapy-free treatments aimed at disrupting the abnormal biology driving its lymphomagenesis. Treatments targeting the constitutive activation of NF-kB, Bruton's Tyrosine Kinase signaling, and anti-apoptosis will be the primary focus as we discuss their clinical data and toxicities. Our review will also focus primarily on the emergence and use of targeted therapies in the relapsed/refractory setting but will also discuss the emergence of their use in front-line therapy and in combination with other agents.

Efficacy and safety of lenalidomide in the treatment of B-cell non-Hodgkin lymphoma

BACKGROUND

The combination of rituximab and chemotherapy is a first-line treatment for patients with B-cell non-Hodgkin lymphoma. Lenalidomide is an immunomodulatory drug that has shown promising properties and activity in a variety of hematological malignancies. This study evaluated the efficacy and safety of lenalidomide-based regimens in the treatment of B-cell non-Hodgkin lymphoma.

METHODS

The PubMed, Science Direct, ClinicalTrials.gov, and Web of Science databases were searched for relevant studies published up to May 2022. Studies with patients diagnosed with non-Hodgkin B-cell lymphoma, who were randomly assigned to a lenalidomide treatment group or a non-lenalidomide control group were considered for inclusion in this review and meta-analysis. Pooled hazard ratios (HRs) with 95% confidence intervals (CIs) of the time-to-event outcomes and risk ratios (RRs) with 95% CIs of dichotomous data were estimated.

RESULTS

A total of 3593 patients from 10 studies were evaluated. The results of the pooled analysis indicated that the lenalidomide-based regimen was associated with prolonged overall survival (HR, 0.85; 95% CI 0.74-0.97; P = 0.02) and progression-free survival (HR, 0.70; 95% CI 0.57-0.88; P = 0.002). Significant differences were found in the overall response rate (RR, 1.18; 95% CI 1.04-1.33; P = 0.01) and complete response rate (RR, 1.18; 95% CI 1.00-1.39; P = 0.05) between the treatment and control groups.

CONCLUSIONS

Lenalidomide appears to be a promising therapeutic agent that offers the possibility of a novel combination of chemotherapy free regimen for patients with B-cell non-Hodgkin lymphoma.

Novel treatment for mantle cell lymphoma - impact of BTK inhibitors and beyond

Mantle cell lymphoma (MCL) primarily affects older adults, accounting for 3-10% of all non-Hodgkin lymphoma (NHL) in western countries. The disease course of MCL is heterogenous; driven by clinical, cytogenetics, and molecular features that shape differences in outcomes, including proliferation index, MIPI scores, and mutational profile such as TP53 aberration. The advent of novel agents has fundamentally evolved the treatment landscape for MCL with treatment strategies that can now be more effectively tailored based on both patient- and disease-specific factors. In this review, we discuss the major classes of novel agents used for the treatment of MCL, focusing on efficacy and notable toxicities of BTK inhibitors. We further examine effective novel combination regimens and, lastly, discuss future directions for the evolution of targeted approaches for the treatment of MCL.

Combating relapsed and refractory Mantle cell lymphoma with novel therapeutic armamentarium: Recent advances and clinical prospects

Mantle cell lymphoma (MCL) is a rare, aggressive subtype of non-Hodgkin's lymphoma (NHL), accounting for 5% of all cases. Due to its virulence factor, it is an incurable disease and keeps relapsing despite an intensive treatment regimen. Advancements in research and drug discovery have shifted the treatment strategy from conventional chemotherapy to targeted agents and immunotherapies. The establishment of the role of Bruton tyrosine kinase led to the development of ibrutinib, a first-generation BTK inhibitor, and its successors. A conditioning regimen based immunotherapeutic agent like ibritumumob, has also demonstrated a viable response with a favorable toxicity profile. Brexucabtagene Autoleucel, the only approved CAR T-cell therapy, has proven advantageous for relapsed/refractory MCL in both children and adults. This article reviews certain therapies that could help update the current approach and summarizes a few miscellaneous agents, which, seldom studied in trials, could alleviate the regression observed in traditional therapies. DATA AVAILABILITY: The datasets generated during and/or analyzed during the current study are available from the corresponding author on reasonable request.

Treatment of older patients with mantle cell lymphoma in the era of novel agents

Mantle cell lymphoma (MCL) is a rare, B-cell non-Hodgkin's lymphoma with a highly heterogeneous presentation that ranges from an indolent disease to an extremely aggressive one. Several clinical and biological prognostic markers can assist in determining the aggressiveness of the disease. Such as MIPI, Ki-67, and TP53, NOTCH1, and CDKN2A mutations. While aggressive chemoimmunotherapy regimens combining rituximab and cytarabine, followed by autologous stem-cell transplantation yield the most promising results, this treatment is too toxic for older patients. Several lower-intensity regimens have shown efficacy in older patients with reduced toxicity profiles. However, older relapsed/refractory patients have an extremely poor outcome. In the last several years, there is a major trend toward chemotherapy-free regimens, targeted therapies such as BTK, BCL-2 and PI3K inhibitors, and immunotherapies such as lenalidomide and CAR-T, which can provide a promising strategy for older patients. Herein we review the current therapies for older MCL patients, chemotherapy regimens, targeted therapies, and immunotherapies.

Beyond Bruton's tyrosine kinase inhibitors in mantle cell lymphoma: bispecific antibodies, antibody-drug conjugates, CAR T-cells, and novel agents

Mantle cell lymphoma is a B cell non-Hodgkin lymphoma (NHL), representing 2-6% of all NHLs and characterized by overexpression of cyclin D1. The last decade has seen the development of many novel treatment approaches in MCL, most notably the class of Bruton's tyrosine kinase inhibitors (BTKi). BTKi has shown excellent outcomes for patients with relapsed or refractory MCL and is now being studied in the first-line setting. However, patients eventually progress on BTKi due to the development of resistance. Additionally, there is an alteration in the tumor microenvironment in these patients with varying biological and therapeutic implications. Hence, it is necessary to explore novel therapeutic strategies that can be effective in those who progressed on BTKi or potentially circumvent resistance. In this review, we provide a brief overview of BTKi, then discuss the various mechanisms of BTK resistance including the role of genetic alteration, cancer stem cells, tumor microenvironment, and adaptive reprogramming bypassing the effect of BTK inhibition, and then provide a comprehensive review of current and emerging therapeutic options beyond BTKi including novel agents, CAR T cells, bispecific antibodies, and antibody-drug conjugates.

Adding venetoclax to lenalidomide and rituximab is safe and effective in patients with untreated mantle cell lymphoma

Mantle cell lymphoma (MCL) is a rare, incurable hematological malignancy with a heterogeneous presentation and clinical course. A wide variety of chemotherapy-based regimens are currently used in patients who are untreated. Over the last several years, several targeted or small-molecule therapies have shown efficacy in the relapsed/refractory setting and have since been explored in the frontline setting. Lenalidomide plus rituximab was explored in a phase 2 study of 38 patients with MCL who were untreated and ineligible to receive transplantation, in which the combination produced durable remissions. We looked to build upon this regimen by adding venetoclax to the combination. We conducted a multicenter, open-label, nonrandomized, single-arm study to evaluate this combination. We enrolled 28 unselected patients with untreated disease irrespective of age, fitness, or risk factors. Lenalidomide was dosed at 20 mg daily from days 1 to 21 of each 28-day cycle. The dose of venetoclax was determined using the time-to-event continual reassessment method. Rituximab was dosed at 375 mg/m2 weekly, starting on cycle 1, day 1 until cycle 2, day 1. No dose-limiting toxicities were noted. All patients were treated with venetoclax at the maximum tolerated dose of 400 mg daily. The most common adverse events were neutropenia and thrombocytopenia. The overall and complete response rates were 96% and 86%, respectively. In total, 86% of patients achieved minimal residual disease undetectability via next-generation sequencing. The median overall and progression-free survivals were not reached. The combination of lenalidomide, rituximab, and venetoclax is a safe and effective regimen in patients with untreated MCL. This trial was registered at www.clinicaltrials.gov as #NCT03523975.

Real-world treatment and outcome patterns of patients with mantle cell lymphoma in China: A large, multicenter retrospective analysis

BACKGROUND

Mantle cell lymphoma (MCL) is an uncommon heterogeneous subtype of B cell non-Hodgkin lymphoma, and clinical features in MCL appear regional characteristics. MCL treatment opinions are not uniform between countries or regions within Asia and China, and Asian patient-specific data for MCL treatment are fewer. The study aims to explore the clinical characteristics, treatment patterns and prognosis of MCL patients in China.

METHODS

A total of 805 patients diagnosed with MCL between April 1999 and December 2019 at 19 comprehensive hospitals in China were included in this retrospective analysis. Kaplan-Meier method coupled with the log-rank test was used for univariate analysis, and COX proportional hazards model was used for multivariate analysis (MVA). p < 0.05 was consided statistically significant. All outputs were produced using R version 4.1.0.

RESULTS

The median age of the cohort was 60.0 years with a male-to-female ratio of 3.36:1. Five-year progression-free survival (PFS) and overall survival (OS) rates were 30.9% and 65.0%, respectively. High-intermediate/high-risk group according to MIPI-c, without high-dose cytarabine, lack of Auto-SCT as consolidation and maintenance treatment and SD/PD in initial treatment remained statistically relevant to poor PFS on MVA, and ki67 ≥50%, B symptoms, high-intermediate/high risk group according to MIPI-c, without high-dose cytarabine, lack of maintenance treatment, SD/PD in initial treatment and relapse/refractory state were independently associated with poorer OS on MVA.

CONCLUSIONS

First-line high dose cytarabine exposure, auto-SCT as consolidation therapy obtained survival benefits in Chinese population. Our study further confirmed the value of maintenance treatment and explored the application of new drug treatment and bendamustine in R/R MCL patients.

Lenalidomide maintenance following high-dose therapy and autologous haematopoietic stem cell transplantation in chemo-resistant or high-risk non-Hodgkin lymphoma: A phase I/II study

Improved maintenance treatments are needed for patients with relapsed/refractory aggressive lymphomas after autologous haematopoietic stem cell transplantation (ASCT). Several studies with lenalidomide have been found to have activity in the treatment of relapsed/refractory aggressive lymphomas. In the present phase I/II, single-arm, open-label study, 59 patients with high-risk relapsed non-Hodgkin lymphoma received pretransplant BEAM chemotherapy and ASCT followed by 12 months of maintenance lenalidomide once daily on Days 1-21 (28-day cycles) beginning at post-transplantation Day 100. The most common histologies were mantle cell lymphoma (56%) and diffuse large B-cell lymphoma (24%). The maximum tolerated dose in the dose-finding part of the study was 15 mg, but cytopenias led to the subsequent adoption of a 10 mg dose in the final study. Sixteen patients (27%) completed 12 cycles of lenalidomide maintenance. The most common reason for discontinuation was adverse events (31%). These were primarily haematologic, and 56% of patients experienced Grade 3-4 events. Two-year PFS rates (95% CIs) were 70% (56%-80%), 45% (19%-68%) and 81% (66%-90%); 2-year OS rates (95% CIs) were 91% (80%-96%), 93% (61%-99%) and 90% (76%-96%) in all patients, patients completing and patients not completing 12-month maintenance respectively. These results do not support the use of lenalidomide maintenance in this setting.

BRUIN MCL-321: phase III study of pirtobrutinib versus investigator choice of BTK inhibitor in BTK inhibitor naive mantle cell lymphoma

Treatment with covalent Bruton tyrosine kinase inhibitors (BTKi) represents an important advance in the management of relapsed or refractory mantle cell lymphoma, but these treatments are not curative and many patients ultimately relapse. Pirtobrutinib, a highly selective, noncovalent (reversible) BTKi, inhibits both wild type and C481-mutant BTK with equal low nM potency, and has favorable oral pharmacology that enables continuous BTK inhibition throughout the dosing interval regardless of intrinsic rate of BTK turnover. Pirtobrutinib is well tolerated and has demonstrated promising efficacy in patients with poor prognosis B-cell malignancies following prior therapy, including covalent BTKi. This phase III, head-to-head, randomized study (NCT04662255) will evaluate whether pirtobrutinib is superior to investigator's choice of covalent BTKi in patients with previously treated, BTKi-naive mantle cell lymphoma.

Treatment Landscape of Relapsed/Refractory Mantle Cell Lymphoma: An Updated Review

Mantle cell lymphoma (MCL) accounts for nearly 2-6% of all non-Hodgkin lymphoma (NHL) cases, with a steady incidence increase over the past few decades. Although many patients achieve an adequate response to the upfront treatment, the short duration of remission with rapid relapse is challenging during MCL management. In this regard, there is no consensus on the best treatment options for relapsed/refractory (R/R) disease, and the international guidelines demonstrate wide variations in the recommended approaches. The last decade has witnessed the introduction of new agents in the treatment landscape of R/R MCL. Since the introduction of Bruton's tyrosine kinase (BTK) inhibitors, the treatment algorithm and response of R/R MCL patients have dramatically changed. Nevertheless, BTK resistance is common, necessitating further investigations to develop novel agents with a more durable response. Novel agents targeting the B-cell receptor (BCR) signaling have exhibited clinical activity and a well-tolerable safety profile. However, as the responses to these novel agents are still modest in most clinical trials, combination strategies were investigated in pre-clinical and early clinical settings to determine whether the combination of novel agents would exhibit a better durable response than single agents. In this report, we provide an updated literature review that covers recent clinical data about the safety and efficacy of novel therapies for the management of R/R MCL.

SOHO State of the Art Updates and Next Questions: Managing Relapsed Mantle Cell Lymphoma

Mantle cell lymphoma (MCL) is a rare subtype of B-cell non-Hodgkin lymphoma i.e., incurable with current therapies. While some patients experience prolonged remissions following initial therapy, most will have a relapsing-remitting course requiring several lines of treatment over the course of their disease. Several targeted therapies are now available to treat patients with relapsed MCL. The Bruton's tyrosine kinase (BTK) inhibitors, including ibrutinib, acalabrutinib, and zanubrutinib, are highly active in MCL and currently approved for treating patients with relapsed disease. Bortezomib and lenalidomide are available as monotherapy or in combination with other agents. Venetoclax is active and can be considered for use in relapsed MCL, although it is not currently approved by regulatory agencies. Chimeric antigen receptor T-cell (CAR-T) therapy with brexucabtagene autoleucel yields high response rates and is now approved for patients with relapsed MCL. Allogeneic stem cell transplant remains an option for a small subset of medically fit and motivated patients who have progressed through multiple lines of therapy, although its use is limited by substantial toxicity. There is currently no standard approach to sequencing therapies for patients with relapsed MCL, and the ability to utilize disease biologic and clinical characteristics to guide treatment decisions in this setting remains limited. In this review, we summarize the current evidence to guide the management of patients with relapsed MCL, review emerging agents and combination therapies that are under investigation, and outline our current treatment approach for these patients.

Tumor Microenvironment and Immunotherapy-Based Approaches in Mantle Cell Lymphoma

Mantle cell lymphoma (MCL) is an aggressive B-cell non-Hodgkin lymphoma (NHL) characterized by the translocation t(11;14) (q13;q32) and a poor response to rituximab–anthracycline-based chemotherapy. High-dose cytarabine-based regimens offer a durable response, but an important number of MCL patients are not eligible for intensive treatment and are ideal candidates for novel targeted therapies (such as BTK, proteasome or BCL2 inhibitors, Immunomodulatory Drugs (IMiDs), bispecific antibodies, or CAR-T cell therapy). On the bench side, several studies aiming to integrate the tumor within its ecosystem highlighted a critical role of the tumor microenvironment (TME) in the expansion and resistance of MCL. This led to important insights into the role of the TME in the management of MCL, including potential targets and biomarkers. Indeed, targeted agents often have a combined mechanism of action on the tumor B cell but also on the tumor microenvironment. The aim of this review is to briefly describe the current knowledge on the biology of the TME in MCL and expose the results of the different therapeutic strategies integrating the TME in this disease.

Local Investigators Significantly Overestimate Overall Response Rates Compared to Blinded Independent Central Reviews in Uncontrolled Oncology Trials: A Comprehensive Review of the Literature

Several drugs gained market authorization based on the demonstration of improved progression-free survival (PFS), adopted as a primary endpoint in Phase 3 clinical trials. In addition, an increasing number of drugs have been granted accelerated approval, and sometimes regular approval, by the main regulatory agencies based on the evaluation of the overall response rate in Phase 1 and 2 clinical trials. However, while the overall survival is an unbiased measure of drug efficacy, these outcomes rely on the assessment of radiological images and patients’ categorization using standardized response criteria. The evaluation of these outcomes may be influenced by subjective factors, particularly when the analysis is performed locally. In fact, blinding of treatment is not always possible in modern oncology trials. Therefore, a blinded independent central review is often adopted to overcome the problem of expectation bias associated with local investigator assessments. In this regard, we have recently observed that local investigators tend to overestimate the overall response rate in comparison to central reviewers in Phase 2 clinical trials, whereas we did not find any significant evaluation bias between local investigators and central reviews when considering progression-free survival in both Phase 2 and 3 trials. In the present article, we have tried to understand the reasons behind this discrepancy by reviewing the available evidence in the literature. In addition, a further analysis of Phase 2 and 3 clinical trials that included the evaluation of both endpoints showed that local investigators significantly overestimate overall response rates compared to blinded independent central reviews in uncontrolled oncology trials.

Mantle Cell Lymphoma: the Role of Risk-Adapted Therapy and Treatment of Relapsed Disease

PURPOSE OF REVIEW

In this review, the current treatment strategies are recapped, evolving agents are discussed, and we provide guidance in treating R/R MCL.

RECENT FINDINGS

There has been an advancement in treatment using targeted therapy, cellular therapies including chimeric antigen receptor (CAR) T cell therapy and hematopoietic stem cell transplantation (HSCT) and novel therapeutic agents including non-covalent BTKis, bispecific antibodies, and antibody-drug conjugates for treatment of refractory and relapsed mantle cell lymphoma. Mantle cell lymphoma (MCL) is a mature B-cell lymphoma that is associated with a poor prognosis. Current treatments include immunochemotherapy, chemotherapy and autologous stem cell transplantation (SCT) which place patients in remission but result in relapse. Chemoimmunotherapy uses chemotherapeutic agents paired with rituximab in patients who have chemo-sensitive disease with prolonged remission of at least > 2 years and/or have contraindications to chemotherapy that serve as bridges to more definitive treatment. Additional therapies including proteosome inhibitor-based therapies and immunomodulators, like bortezomib and lenalidomide, can be used as single agents or in combination with others. Bruton's tyrosine kinase (BTK) inhibitors including ibrutinib, acalaburtinib, and zanubrutinib have also been proven effective for the treatment of (R/R) disease. Another agent is Venetoclax, a robust drug that can be used in MCL after progression or intolerance to BTKi. Newer advances in the management of MCL have led to the utilization of cellular therapies including chimeric antigen receptor (CAR) T cell therapy and SCT that are options for healthy young (< 65 years old) who have progressed through several lines of therapies. With progression of disease, mutations are acquired that cause therapy resistance. Novel therapeutic agents such as non-covalent BTKis, bispecific antibodies, and antibody-drug conjugates are paving the way for advancements in treatment for R/R MCL. R/R MCL is a complex disease with many therapeutic options none of which has been proven superior in head-to-head comparison. In this review, the current treatment strategies are recapped, evolving agents are discussed, and we provide guidance in treating R/R MCL.

Mantle cell lymphoma in 2022-A comprehensive update on molecular pathogenesis, risk stratification, clinical approach, and current and novel treatments

The field of mantle cell lymphoma (MCL) has witnessed remarkable progress due to relentless advances in molecular pathogenesis, prognostication, and newer treatments. MCL consists of a spectrum of clinical subtypes. Rarely, atypical cyclin D1-negative MCL and in situ MCL neoplasia are identified. Prognostication of MCL is further refined by identifying somatic mutations (such as TP53, NSD2, KMT2D), methylation status, chromatin organization pattern, SOX-11 expression, minimal residual disease (MRD), and genomic clusters. Lymphoid tissue microenvironment studies demonstrated the role of B-cell receptor signaling, nuclear factor kappa B (NF-kB), colony-stimulating factor (CSF)-1, the CD70-SOX-11 axis. Molecular mechanism of resistance, mutation dynamics, and pathogenic pathways (B-cell receptor (BCR), oxidative phosphorylation, and MYC) were identified in mediating resistance to various treatments (bruton tyrosine kinase (BTK) inhibitors [ibrutinib, acalabrutinib]. Treatment options range from conventional chemoimmunotherapy and stem cell transplantation (SCT) to targeted therapies against BTK (covalent and noncovalent), Bcl2, ROR1, cellular therapy such as anti-CD19 chimeric antigen receptor therapy (CAR-T), and most recently bispecific antibodies against CD19 and CD20. MCL patients frequently relapse. Complex pathogenesis and the management of patients with progression after treatment with BTK/Bcl2 inhibitors and CAR-T (triple-resistant MCL) remain a challenge. Next-generation clinical trials incorporating newer agents and concurrent translational and molecular investigations are ongoing.

Relapsed/Refractory Mantle Cell Lymphoma: Beyond BTK Inhibitors

Mantle cell lymphoma (MCL) is a rare mature B-cell non-Hodgkin lymphoma (B-NHL) with historically poor outcomes. Virtually all patients will eventually experience refractory or relapsed (R/R) disease, with a virulent course of resistance and serial relapses, making treatment challenging. The available therapies for R/R MCL are not curative with conventional therapy, their goal being to palliate and prolong survival. A variety of agents approved for R/R MCL, including Bruton's tyrosine kinase inhibitors (BTKi), changed the treatment landscape of R/R MCL. In the pre-BTKi era, the median progression-free survival (PFS) in R/R disease was 4-9 months. With the introduction of ibrutinib, the median PFS improved to 13-14.6 months. Despite these impressive results, the duration of response is limited, and resistance to BTKi inevitably develops in a subset of patients. Outcomes after progression on BTKi are extremely poor, with a median overall survival (OS) of 6 to 10 months. Certain therapies, such as chimeric antigen receptor (CAR) T cells, have shown promising results after BTKi failure. The preferred combination and sequencing of therapies beyond BTKi remain unestablished and are currently being investigated. In this review, we describe the current evidence for the available treatment of R/R MCL after progression on BTKi.

Regulation of B-Cell Receptor Signaling and Its Therapeutic Relevance in Aggressive B-Cell Lymphomas

The proliferation and survival signals emanating from the B-cell receptor (BCR) constitute a crucial aspect of mature lymphocyte's life. Dysregulated BCR signaling is considered a potent contributor to tumor survival in different subtypes of B-cell non-Hodgkin lymphomas (B-NHLs). In the last decade, the emergence of BCR-associated kinases as rational therapeutic targets has led to the development and approval of several small molecule inhibitors targeting either Bruton's tyrosine kinase (BTK), spleen tyrosine kinase (SYK), or phosphatidylinositol 3 kinase (PI3K), offering alternative treatment options to standard chemoimmunotherapy, and making some of these drugs valuable assets in the anti-lymphoma armamentarium. Despite their initial effectiveness, these precision medicine strategies are limited by primary resistance in aggressive B-cell lymphoma such as diffuse large B-cell lymphoma (DLBCL) and mantle cell lymphoma (MCL), especially in the case of first generation BTK inhibitors. In these patients, BCR-targeting drugs often fail to produce durable responses, and nearly all cases eventually progress with a dismal outcome, due to secondary resistance. This review will discuss our current understanding of the role of antigen-dependent and antigen-independent BCR signaling in DLBCL and MCL and will cover both approved inhibitors and investigational molecules being evaluated in early preclinical studies. We will discuss how the mechanisms of action of these molecules, and their off/on-target effects can influence their effectiveness and lead to toxicity, and how our actual knowledge supports the development of more specific inhibitors and new, rationally based, combination therapies, for the management of MCL and DLBCL patients.

Therapeutic options for relapsed/refractory mantle cell lymphoma

Mantle cell lymphoma (MCL) is an uncommon subtype of non-Hodgkin lymphoma in which immunochemotherapy, with or without high-dose therapy, and autologous stem cell transplantation remain standard frontline therapies. Despite their clear efficacy, patients inevitably relapse and require subsequent therapy. In this review, we discuss the key therapeutic approaches in the management of relapsed MCL, covering in depth the data supporting the use of covalent Bruton tyrosine kinase (BTK) inhibitors at first or subsequent relapse. We describe the outcomes of patients progressing through BTK inhibitors and discuss the mechanisms of covalent BTKi resistance and treatment options after covalent treatment with BTKi. Options in this setting may depend on treatment availability, patient's and physician's preference, and the patient's age and comorbidity status. We discuss the rapid recent development of anti-CD19 chimeric antigen receptor T-cell therapy, as well as the utility of allogenic stem cell transplantation and novel therapies, such as noncovalent, reversible BTK inhibitors; ROR1 antibody drug conjugates; and bispecific antibodies.

Targeted Drug Delivery and Theranostic Strategies in Malignant Lymphomas

Malignant lymphomas represent the most common type of hematologic malignancies. The first clinically approved TDD modalities in lymphoma patients were anti-CD20 radioimmunoconjugates (RIT) 131I-tositumomab and 90Y-ibritumomab-tiuxetan. The later clinical success of the first approved antibody-drug conjugate (ADC) for the treatment of lymphomas, anti-CD30 brentuximab vedotin, paved the path for the preclinical development and clinical testing of several other ADCs, including polatuzumab vedotin and loncastuximab tesirine. Other modalities of TDD are based on new formulations of "old" cytostatic agents and their passive trapping in the lymphoma tissue by means of the enhanced permeability and retention (EPR) effect. Currently, the diagnostic and restaging procedures in aggressive lymphomas are based on nuclear imaging, namely PET. A theranostic approach that combines diagnostic or restaging lymphoma imaging with targeted treatment represents an appealing innovative strategy in personalized medicine. The future of theranostics will require not only the capability to provide suitable disease-specific molecular probes but also expertise on big data processing and evaluation. Here, we review the concept of targeted drug delivery in malignant lymphomas from RIT and ADC to a wide array of passively and actively targeted nano-sized investigational agents. We also discuss the future of molecular imaging with special focus on monoclonal antibody-based and monoclonal antibody-derived theranostic strategies.

Current Knowledge in Genetics, Molecular Diagnostic Tools, and Treatments for Mantle Cell Lymphomas

Mantle Cell lymphoma (MCL) is a mature B-cell lymphoma with a well-known hallmark genetic alteration in most cases, t (11,14)(q13q32)/CCND1-IGH. However, our understanding of the genetic and epigenetic alterations in MCL has evolved over the years, and it is now known that translocations involving CCND2, or cryptic insertion of enhancer elements of IGK or IGL gene, can also lead to MCL. On a molecular level, MCL can be broadly classified into two subtypes, conventional MCL (cMCL) and non-nodal MCL (nnMCL), each with different postulated tumor cell origin, clinical presentation and behavior, mutational pattern as well as genomic complexity. This article reviews both the common and rare alterations in MCL on a gene mutational, chromosomal arm, and epigenetic level, in the context of their contribution to the lymphomagenesis and disease evolution in MCL. This article also summarizes the important prognostic factors, molecular diagnostic tools, and treatment options based on the most recent MCL literature.

Sequencing of Novel Therapies for Mantle Cell Lymphoma

OPINION STATEMENT

There is no standard approach to sequencing novel therapies in mantle cell lymphoma (MCL). For initial treatment, intensive induction chemotherapy followed by autologous stem cell transplant and rituximab maintenance remains our preferred approach in young, fit patients. We consider bendamustine plus rituximab or lenalidomide plus rituximab in patients who are ineligible for intensive chemotherapy-based approaches. Bruton's tyrosine kinase inhibitors are our preferred class of agents to use in the second-line setting. When patients inevitably relapse on one of these agents, we proceed with chimeric antigen receptor T-cell (CAR T) therapy in eligible patients, often with the use of bridging therapy with corticosteroids, lenalidomide, or venetoclax. We treat patients who are ineligible for CAR T or clinic trial with venetoclax, lenalidomide, or proteosome inhibitor-based regimens, although efficacy is expected to be limited in this setting with a shortened duration of response to each subsequent line of therapy. Allogeneic stem cell transplant remains an option for carefully selected patients who progress after autologous stem cell transplant and CAR T. Clinical trials involving combinations of novel agents in early lines of therapy are ongoing, and new compounds with unique mechanisms of action are in development. The results of ongoing clinical trials with novel agents will further change the treatment landscape for patients with MCL in the coming years.

Immunomodulatory Drugs for the Treatment of B Cell Malignancies

Accumulating evidence suggests that the tumor microenvironment (TME) is involved in disease progression and drug resistance in B cell malignancies, by supporting tumor growth and facilitating the ability of malignant cells to avoid immune recognition. Immunomodulatory drugs (IMiDs) such as lenalidomide have some direct anti-tumor activity, but critically also target various cellular compartments of the TME including T cells, NK cells, and stromal cells, which interfere with pro-tumor signaling while activating anti-tumor immune responses. Lenalidomide has delivered favorable clinical outcomes as a single-agent, and in combination therapy leads to durable responses in chronic lymphocytic leukemia (CLL) and several non-Hodgkin lymphomas (NHLs) including follicular lymphoma (FL), diffuse large B cell lymphoma (DLBCL), and mantle cell lymphoma (MCL). Recently, avadomide, a next generation cereblon E3 ligase modulator (CELMoD), has shown potent anti-tumor and TME immunomodulatory effects, as well as promising clinical efficacy in DLBCL. This review describes how the pleiotropic effects of IMiDs and CELMoDs could make them excellent candidates for combination therapy in the immuno-oncology era-a concept supported by preclinical data, as well as the recent approval of lenalidomide in combination with rituximab for the treatment of relapsed/refractory (R/R) FL.

Five year experience in ibrutinib therapy for relapsed and refractory mantle cell lymphoma in real world Russian clinical practice

Background. Mantle cell lymphoma (MCL) is a rare and clinically aggressive lymphoma subtype. Current approaches have greatly improved patients outcomes, but relapse is inevitable. In phase IIIII clinical trials, ibrutinib has shown significant activity in patients with relapsed or refractory (R/R) MCL. Aim. To assess efficacy and toxicity of ibrutinib monotherapy in patients with R/R MCL in routine practice outside of clinical trials. Materials and methods. The study enrolled patients with confirmed R/R MCL who had received at least one line of previous chemotherapy. ECOG 24, cytopenia, infectious complications, hemorrhagic syndrome were not exclusion criteria. Patients received daily oral ibrutinib 560 mg until progression or unacceptable toxicity. Results. From May 2015 to September 2020 ibrutinib therapy was started in 106 patients with R/R MCL in 16 regions of Russia. The median age was 66 years; ECOG2 18%, blastoid variant (or Ki6740% or WBC50109/l) 43%. The median number of previous treatment lines was 2 (111). The ORR was 78.4% (CRR 27.4%). The median PFS was 13.6 months and OS 23.2 months. In the blastoid group the median PFS was 4.4 months vs 36.5 months in the alternative group (p0.001), the median OS 9.0 vs 41.0 (p=0.001). The median OS of patients after progression on ibrutinib was 3.2 months. The common complications are hemorrhages (63%), diarrhea (62%), myalgia and muscle cramps (60%), infections (31%), skin and nail toxicity 15%, arrhythmia 8%. None of recipients had to completely discontinue ibrutinib therapy due to complications. Conclusion. Ibrutinib is effective and well tolerated in routine practice of R/R MCL treatment and our results are consistent with international clinical trials. The favorable toxicity profile and the high response rate made it possible to prescribe ibrutinib in severe somatic status, cytopenia, and even in the presence of infectious complications.

Cancer therapies based on targeted protein degradation - lessons learned with lenalidomide

For decades, anticancer targeted therapies have been designed to inhibit kinases or other enzyme classes and have profoundly benefited many patients. However, novel approaches are required to target transcription factors, scaffolding proteins and other proteins central to cancer biology that typically lack catalytic activity and have remained mostly recalcitrant to drug development. The selective degradation of target proteins is an attractive approach to expand the druggable proteome, and the selective oestrogen receptor degrader fulvestrant served as an early example of this concept. Following a long and tragic history in the clinic, the immunomodulatory imide drug (IMiD) thalidomide was discovered to exert its therapeutic activity via a novel and unexpected mechanism of action: targeting proteins to an E3 ubiquitin ligase for subsequent proteasomal degradation. This discovery has paralleled and directly catalysed myriad breakthroughs in drug development, leading to the rapid maturation of generalizable chemical platforms for the targeted degradation of previously undruggable proteins. Decades of clinical experience have established front-line roles for thalidomide analogues, including lenalidomide and pomalidomide, in the treatment of haematological malignancies. With a new generation of 'degrader' drugs currently in development, this experience provides crucial insights into class-wide features of degraders, including a unique pharmacology, mechanisms of resistance and emerging therapeutic opportunities. Herein, we review these past experiences and discuss their application in the clinical development of novel degrader therapies.

Zanubrutinib for the treatment of relapsed or refractory mantle cell lymphoma

Zanubrutinib, a highly selective Bruton tyrosine kinase inhibitor, was evaluated in a phase 1/2 study in patients with various B-cell malignancies. In the subgroup of patients with relapsed/refractory (R/R) mantle cell lymphoma (MCL), zanubrutinib was administered as 160 mg twice daily (n = 14), 320 mg once daily (n = 18), or ≤160 mg total dose (n = 5). Herein, we report results for patients receiving a total daily dose of 320 mg (N = 32). Median study follow-up was 18.8 months. Eighteen patients discontinued treatment, 10 because of progressive disease and 8 because of adverse events (AEs); 1 AE (peripheral edema) was considered to be related to zanubrutinib treatment. The most common AEs were diarrhea (43.8%), contusion (37.5%), constipation (31.3%), and upper respiratory tract infection (31.3%). Infection was the most commonly reported AE of interest (18.8% of patients experienced grade ≥3 infection). At least 1 AE of grade ≥3 was reported in 59.4% of patients; grade ≥3 AEs that were reported in >2 patients were anemia (12.5%), pneumonia (9.4%), and myalgia (9.4%). Overall response rate was 84%, with 25% achieving a complete response. Median duration of response was 18.5 months. Median progression-free survival (PFS) was 21.1 months. Zanubrutinib was well tolerated and demonstrated activity in patients with R/R MCL. The trial is registered at www.clinicaltrials.gov as #NCT02343120.

Mantle cell lymphoma - advances in molecular biology, prognostication and treatment approaches

Mantle cell lymphoma (MCL) is clinically characterised by its heterogenous behaviour with courses ranging from indolent cases that do not require therapy for years to highly aggressive MCL with a very limited prognosis. A better understanding of the complex biology of MCL has already led to the approval of several innovative agents, expanding the landscape of MCL therapies and improving therapeutic options especially for refractory/relapsed (R/R) disease. Nevertheless, to further optimise MCL treatment, early identification of individual risk profile and risk-adapted, patient-tailored choice of therapeutic strategy needs to be prospectively incorporated into clinical patient management. The present review highlights recent advances in deciphering the molecular background of MCL, the definition of prognostically relevant factors and the identification of potential druggable targets and summarises current treatment recommendations for primary and R/R MCL including novel targeted therapies.

Novel Treatments for Mantle Cell Lymphoma: From Targeted Therapies to CAR T Cells

Mantle cell lymphoma is a rare B-cell non-Hodgkin's lymphoma that retains a sobering prognosis despite an extensive research effort. Mantle cell lymphoma remains incurable even with aggressive, and at times toxic, chemoimmunotherapy with early incorporation of autologous stem cell transplantation. Given this, attention has turned to the use of targeted therapies addressing dysregulation of B-cell signaling pathways. Drugs such as immunomodulatory agents, proteasome inhibitors, and Bruton's tyrosine kinase inhibitors have shown success in the relapsed/refractory population, and there is ongoing investigation into the utilization of novel Bruton's tyrosine kinase, B-cell leukemia/lymphoma-2, and spleen tyrosine kinase inhibitors alone or in combination in both the front-line and relapsed settings. Other areas of research in novel immunotherapies include investigations of bispecific T-cell engagers and antibody-drug conjugates. Most recently, chimeric antigen receptor T-cell therapy has been granted US Food and Drug Administration approval as a result of durable remissions even in high-risk patients who have classically done poorly with traditional chemoimmunotherapy. The intent of this article is to review the literature describing these selective therapies and discuss their current and future roles in the treatment of mantle cell lymphoma.

Novel synthetic drugs for the treatment of non-Hodgkin lymphoma

Introduction: Over the past two decades, deeper understanding of B-cell signaling pathways and other mechanisms of lymphomagenesis have yielded promising targets for novel drugs in the treatment of non-Hodgkin lymphoma.Areas covered: This article provides a comprehensive review of approved synthetic drugs targeting the BTK, PI3K, immunomodulation, proteasome, HDAC, EZH2, and nuclear export pathways in non-Hodgkin lymphoma. The review includes coverage of the pharmacology, efficacy, toxicity, and active areas of research for each drug. The authors also provide their expert perspectives on the field and their opinions for the future.Expert opinion: Although novel synthetic drugs have generally not impacted clinical practice to the same extent as immune and cellular therapies, there remains an important role for targeted drugs in the treatment of non-Hodgkin lymphoma, particularly in the relapsed setting and for patients ineligible for more intensive therapies. Clinical outcomes and tolerability may improve further with the development of newer generations of synthetic drugs and emerging combination regimens with other targeted and immune therapies.

Relapsed Mantle Cell Lymphoma: Current Management, Recent Progress, and Future Directions

The increasing number of approved therapies for relapsed mantle cell lymphoma (MCL) provides patients effective treatment options, with increasing complexity in prioritization and sequencing of these therapies. Chemo-immunotherapy remains widely used as frontline MCL treatment with multiple targeted therapies available for relapsed disease. The Bruton's tyrosine kinase inhibitors (BTKi) ibrutinib, acalabrutinib, and zanubrutinib achieve objective responses in the majority of patients as single agent therapy for relapsed MCL, but differ with regard to toxicity profile and dosing schedule. Lenalidomide and bortezomib are likewise approved for relapsed MCL and are active as monotherapy or in combination with other agents. Venetoclax has been used off-label for the treatment of relapsed and refractory MCL, however data are lacking regarding the efficacy of this approach particularly following BTKi treatment. Anti-CD19 chimeric antigen receptor T-cell (CAR-T) therapies have emerged as highly effective therapy for relapsed MCL, with the CAR-T treatment brexucabtagene autoleucel now approved for relapsed MCL. In this review the authors summarize evidence to date for currently approved MCL treatments for relapsed disease including sequencing of therapies, and discuss future directions including combination treatment strategies and new therapies under investigation.

Lenalidomide maintenance after autologous haematopoietic stem-cell transplantation in mantle cell lymphoma: results of a Fondazione Italiana Linfomi (FIL) multicentre, randomised, phase 3 trial

BACKGROUND

Fit patients with mantle cell lymphoma aged 18-65 years are usually given cytarabine and rituximab-based induction regimens followed by autologous haematopoetic stem-cell transplantation (HSCT). We investigated whether post-autologous HSCT maintenance with lenalidomide improves progression-free survival in this population.

METHODS

This open-label, randomised, multicentre, phase 3 trial was done at 49 haematology and oncology units in Italy and Portugal. Eligible patients had Ann Arbor stage III or IV treatment-naive mantle cell lymphoma (or stage II plus bulky disease [≥5 cm] or B symptoms), and had evidence of cyclin D1 overexpression or the translocation t(11;14)(q13;q32). Patients were aged 18-59 years with Eastern Cooperative Oncology Group (ECOG) performance status 0-3, or aged 60-65 years with ECOG 0-2. After an optional prephase with vincristine and steroids (intravenous vincristine 1·4 mg/m² on day 1, oral prednisone 100 mg [total dose] on days 1-5), patients were given three courses of R-CHOP (21-day cycle, intravenous rituximab 375 mg/m² on day 1; intravenous doxorubicin 50 mg/m², vincristine 1·4 mg/m², and cyclophosphamide 750 mg/m² on day 2; oral prednisone 100 mg/m² on day 2-6). Patients then received one cycle of high-dose CTX (intravenous cyclophosphamide 4 g/m² on day 1, intravenous rituximab 375 mg/m² on day 4). After restaging, patients received two cycles of R-HD-cytarabine (high-dose intravenous cytarabine 2 g/m² every 12 h on days 1-3, intravenous rituximab 375 mg/m² on days 4 and 10). Patients with complete remission or partial remission proceeded to autologous HSCT and responding patients (complete remission or partial remission) with haematological recovery were randomly assigned (1:1) to receive 24 courses of oral lenalidomide maintenance (15 mg per day for patients with platelets >100 × 10⁹ cells per L or 10 mg per day for platelets 60-100 × 10⁹ cells per L, days 1-21 every 28 days) for 24 months, or observation. The primary endpoint was progression-free survival, measured in the randomised population. This study is registered with EudraCT (2009-012807-25) and ClinicalTrials.gov (NCT02354313).

FINDINGS

Between May 4, 2010, and Aug 24, 2015, 303 patients were screened for inclusion and 300 patients were enrolled (median age 57 years, IQR 51-62; 235 [78%] male). 95 patients were excluded before randomisation, mostly due to disease progression, adverse events, and inadequate recovery. 104 patients were randomly assigned to the lenalidomide maintenance group and 101 patients to the observation group. 11 (11%) of 104 patients assigned to lenalidomide did not start treatment (3 withdrew, 6 adverse events or protocol breach, 2 lost to follow-up). At a median follow-up of 38 months after randomisation (IQR 24-50), 3-year progression-free survival was 80% (95% CI 70-87) in the lenalidomide group versus 64% (53-73) in the observation group (log-rank test p=0·012; hazard ratio 0·51, 95% CI 0·30-0·87). 41 (39%) of 104 patients discontinued lenalidomide for reasons including death or progression. Treatment-related deaths were recorded in two (2%) of 93 patients in the lenalidomide group (1 pneumonia, 1 thrombotic thrombocytopenic purpura), and one (1%) of 101 in the observation group (pneumonia). 59 (63%) of 93 patients in the lenalidomide group had grade 3-4 haematological adverse events versus 12 (12%) of 101 patients in the observation group (p<0·0001). 29 (31%) of 93 patients in the lenalidomide group and eight (8%) of 101 patients in the observation group had grade 3-4 non-haematological adverse events (p<0·0001), of which infections were the most common.Serious adverse events were reported in 22 (24%) of 93 patients in the lenalidomide group and five (5%) of 101 patients in the observation group. Pneumonia and other infections were the most common serious adverse events.

INTERPRETATION

Despite non-negligibile toxicity, lenalidomide after autologous HSCT improved progression-free survival in patients with mantle cell lymphoma, highlighting the role of maintenance in mantle cell lymphoma.

FUNDING

Fondazione Italiana Linfomi and Celgene.

Local Investigators Significantly Overestimate Overall Response Rates Compared to Blinded Independent Central Reviews in Phase 2 Oncology Trials

The overall response rate (ORR) is a largely adopted outcome measure in early-phase oncology trials. ORR is highly relevant in cancer drug development at the time of deciding whether to move to confirmatory phase 3 trials; moreover, ORR is gaining increasing relevance in fast-track registration procedures. No systematic analysis has been conducted so far to investigate whether a discrepancy exists between ORR assessed by local investigators and those assessed by blinded reviewers in phase 2 oncology trials. In this study, we carried out a search in the clinicaltrials.gov and EudraCT databases, looking at the trials reporting the results of both investigator-assessed and independently-assessed ORR. A discrepancy index was obtained by calculating the ratio of each investigator-assessed ORR on the corresponding independently assessed ORR, so that a discrepancy index >1 indicates that the investigator was "more optimistic," whereas a discrepancy index <1 indicates the opposite. We also analyzed different subgroups (by tumor type, by drug type, by year). Twenty trials met the search criteria; in some cases, >1 comparison was conducted in the trial, so that the total number of comparisons analyzed was 33. The estimated mean discrepancy index was 1.175 (95% confidence interval, 1.083-1.264; n = 33). In conclusion, local investigators significantly overestimate ORR compared to paired blinded reviewers in phase 2 oncology trials. This may represent a risk in drug development, when deciding whether to move to confirmatory, more expensive phase 3 trials. Blinded independent central review should be used in ORR assessment if a more conservative estimate of treatment efficacy is required, as in the case of fast-track drug developments leading to accelerated approvals of cancer therapies.

Current Immunotherapy Approaches in Non-Hodgkin Lymphomas

Non-Hodgkin lymphomas (NHLs) are lymphoid malignancies of B- or T-cell origin. Despite great advances in treatment options and significant improvement of survival parameters, a large part of NHL patients either present with a chemotherapy-refractory disease or experience lymphoma relapse. Chemotherapy-based salvage therapy of relapsed/refractory NHL is, however, capable of re-inducing long-term remissions only in a minority of patients. Immunotherapy-based approaches, including bispecific antibodies, immune checkpoint inhibitors and genetically engineered T-cells carrying chimeric antigen receptors, single-agent or in combination with therapeutic monoclonal antibodies, immunomodulatory agents, chemotherapy or targeted agents demonstrated unprecedented clinical activity in heavily-pretreated patients with NHL, including chemotherapy-refractory cases with complex karyotype changes and other adverse prognostic factors. In this review, we recapitulate currently used immunotherapy modalities in NHL and discuss future perspectives of combinatorial immunotherapy strategies, including patient-tailored approaches.

The safety of available chemo-free treatments for mantle cell lymphoma

INTRODUCTION

Conventional treatment for mantle cell lymphoma (MCL) patients includes regimens combining rituximab with other cytotoxic drugs, followed or not by consolidation with autologous stem cell transplantation and rituximab maintenance. However, older, unfit, and relapsed/refractory patients are often ineligible for intense treatment. Currently, available new targeted treatment options seem to offer hope in this group of patients.

AREAS COVERED

This article reviews the safety profiles of new therapeutic chemotherapy-free options for MCL patients. Publications in English from 2010 through June 2020 were surveyed on the MEDLINE database for articles. Proceedings of the American Society of Hematology during the last 5 years were also included.

EXPERT OPINION

MCL is a clinically heterogenous disease predominantly affecting elderly patients. Its variable clinical course requires personalization and individualization of treatment to achieve optimal survival and acceptable safety profiles, especially in poor prognosis patients. Results of clinical trials performed in the past decade indicated that novel drugs used as a single agent or as part of a conventional chemotherapeutic treatment offer promise in minimalizing the relapse rate for MCL and may allow more effective and safer treatment options by reducing the risk of adverse events, especially cytopenias and infections.

Mantle cell lymphoma: insights into therapeutic targets at the preclinical level

INTRODUCTION

Mantle cell lymphoma (MCL) is a chronically relapsing B-cell non-Hodgkin lymphoma characterized by recurrent molecular-cytogenetic aberrations that lead to deregulation of DNA damage response, cell cycle progression, epigenetics, apoptosis, proliferation, and motility. In the last 10 years, clinical approval of several innovative drugs dramatically changed the landscape of treatment options in the relapsed/refractory (R/R) MCL, which translated into significantly improved survival parameters.

AREAS COVERED

Here, up-to-date knowledge on the biology of MCL together with currently approved and clinically tested frontline and salvage therapies are reviewed. In addition, novel therapeutic targets in MCL based on the scientific reports published in Pubmed are discussed.

EXPERT OPINION

Bruton tyrosine-kinase inhibitors, NFkappaB inhibitors, BCL2 inhibitors, and immunomodulary agents in combination with monoclonal antibodies and genotoxic drugs have the potential to induce long-term remissions in majority of newly diagnosed MCL patients. Several other classes of anti-tumor drugs including phosphoinositole-3-kinase, cyclin-dependent kinase or DNA damage response kinase inhibitors have demonstrated promising anti-lymphoma efficacy in R/R MCL. Most importantly, adoptive immunotherapy with genetically modified T-cells carrying chimeric antigen receptor represents a potentially curative treatment approach even in the patients with chemotherapy and ibrutinib-refractory disease.

Key Clinical and Translational Research Questions to Address Unmet Needs in Mantle Cell Lymphoma

Survival for patients with mantle cell lymphoma has improved dramatically over the last 2 decades owing to a better understanding of disease biology and the development of more effective treatment regimens for patients with untreated and relapsed disease. With these advancements, we are now poised to ask questions that challenge old treatment strategies, use new technologies, and improve our understanding of disease heterogeneity. This article focuses on questions that we believe will drive the future of mantle cell lymphoma treatment. Although not an exhaustive list, we review current literature, ongoing studies, and provide expert opinion on future trial design.

Approach to the Initial Treatment of Older Patients with Mantle Cell Lymphoma

With a median age of 65 years, mantle cell lymphoma affects predominantly older patients with comorbidities. Initial treatment of older patients is not standardized but traditionally includes chemoimmunotherapy regimens that are not curative. Incorporation of maintenance strategy after induction and introduction of novel agents have expanded access to effective treatment options and improved survival outcome. Ongoing randomized studies comparing induction regimens and maintenance strategies are expected to further define the role of novel agents and combinations in the initial treatment of older patients with mantle cell lymphoma.

Current Role and Emerging Evidence for Bruton Tyrosine Kinase Inhibitors in the Treatment of Mantle Cell Lymphoma

The Bruton tyrosine kinase inhibitors (BTKi), acalabrutinib, ibrutinib, and zanubrutinib, are all approved in the United States for the treatment of relapsed mantle cell lymphoma (MCL). BTKi as a class have become the preferred therapy for most of the patients with relapsed MCL, and ongoing clinical trials are evaluating whether combining BTKi with other targeted agents may deepen response and further improve outcomes. Emerging evidence supports the efficacy of BTKi-containing combinations as frontline treatment, and clinical studies to define the role of this class of drugs for newly diagnosed patients with MCL are in progress.

Chemotherapy combinations for B-cell lymphoma and chemo-free approach in elderly patients: an update on best practice

INTRODUCTION

Elderly patients represent a consistent portion of new diagnoses of B cell Non-Hodgkin Lymphoma (B-NHL). The treatment approach in this setting can be challenging for clinicians due to treatment toxicities and patients' comorbidities to deal with. Immunochemotherapy still represents the main option in the front-line setting for diffuse large B cell lymphoma (DLBCL), follicular lymphoma (FL), and mantle cell lymphoma (MCL), with different options to choose depending on patient characteristics. In the last decade, a number of new drugs and combinations have been investigated, demonstrating efficacy and safety even in the older population and extending the spectrum of treatment choices for this setting.

AREAS COVERED

This article reviews the majority data in literature on immunochemotherapy regimens and chemo-free approaches available for DLBCL, FL, and MCL in the elderly, both in front-line and relapse/refractory setting, the incoming drugs and how to identify the best option for each patient.

EXPERT OPINION

The therapeutic approach for elderly B-NHL is challenging and a tailored approach guided by a geriatric assessment is mandatory, in order to optimize efficacy and minimize treatment-related toxicities. The more extended use of biological drugs may potentially lead to prolonged survival with reduction of toxicities and improved quality of life.

IMiDs New and Old

PURPOSE OF REVIEW

IMiDs are a class of biologic agents with immunomodulatory, anti-angiogenic, and direct anti-cancer activities. This review summarizes current data on clinical development and application of IMiDs in non-Hodgkin lymphoma (NHL) subtypes, focusing primarily on lenalidomide, with additional discussion on managing common side effects.

RECENT FINDINGS

Improved upon the prototype thalidomide, the second-generation compound lenalidomide has enhanced immunological and anti-cancer properties with fewer side effects, while next-generation small molecule cereblon/E3 ubiquitin ligase modulator CC-122 is in early clinical studies. Lenalidomide is FDA-approved for treatment of relapsed/refractory mantle cell lymphoma as a single agent, as well as in combination with rituximab for R/R follicular lymphoma and marginal zone lymphoma. In addition, numerous clinical trials of lenalidomide, as single agent, in combination with anti-CD20 antibodies, or in combination with chemoimmunotherapy regimens, have shown promise in aggressive and indolent NHL in both the upfront and relapsed/refractory setting. As clinical trials with lenalidomide continue to find success in both indolent and aggressive lymphomas, IMiDs are poised to be important building blocks for combinatorial strategies with antibodies, chemotherapy, novel target agents, and emerging immunotherapy involving immune checkpoint inhibitors and chimeric antigen receptor T cell (CAR-T) therapy. Delineation of treatment-specific and disease-specific biomarkers is an important research objective to gain insight into potential mechanisms of action, and to guide future clinical development.