Recent advances in genomics and therapeutics in mantle cell lymphoma

Over the past decades, significant strides have been made in understanding the pathobiology, prognosis, and treatment options for mantle cell lymphoma (MCL). The heterogeneity observed in MCL's biology, genomics, and clinical manifestations, including indolent and aggressive forms, is intricately linked to factors such as the mutational status of the variable region of the immunoglobulin heavy chain gene, epigenetic profiling, and Sox11 expression. Several intriguing subtypes of MCL, such as Cyclin D1-negative MCL, in situ mantle cell neoplasm, CCND1/IGH FISH-negative MCL, and the impact of karyotypic complexity on prognosis, have been explored. Notably, recent immunochemotherapy regimens have yielded long-lasting remissions in select patients. The therapeutic landscape for MCL is continuously evolving, with a shift towards nonchemotherapeutic agents like ibrutinib, acalabrutinib, and venetoclax. The introduction of BTK inhibitors has brought about a transformative change in MCL treatment. Nevertheless, the challenge of resistance to BTK inhibitors persists, prompting ongoing efforts to discover strategies for overcoming this resistance. These strategies encompass non-covalent BTK inhibitors, immunomodulatory agents, BCL2 inhibitors, and CAR-T cell therapy, either as standalone treatments or in combination regimens. Furthermore, developing novel drugs holds promise for further improving the survival of patients with relapsed or refractory MCL. In this comprehensive review, we methodically encapsulate MCL's clinical and pathological attributes and the factors influencing prognosis. We also undertake an in-depth examination of stratified treatment alternatives. We investigate conceivable resistance mechanisms in MCL from a genetic standpoint and offer precise insights into various therapeutic approaches for relapsed or refractory MCL.

Impact of diagnosis to treatment interval in patients with newly diagnosed mantle cell lymphoma

The prognostic relevance of diagnosis to treatment interval (DTI) in patients with newly diagnosed mantle cell lymphoma (MCL) is unknown. Hence, we sought to evaluate the impact of DTI on outcomes in MCL using 3 large datasets (1) the University of Iowa/Mayo Clinic Specialized Program of Research Excellence Molecular Epidemiology Resource, (2) patients enrolled in the ALL Age Asthma Cohort/CALGB 50403, and (3) a multisitecohort of patients with MCL. Patients were a priori divided into 2 groups, 0 to 14 days (short DTI) and 15 to 60 days (long DTI). The patients in whom observation was deemed appropriate were excluded. One thousand ninety-seven patients newly diagnosed with MCL and available DTI were included in the study. The majority (73%) had long DTI (n=797). Patients with short DTI had worse eastern cooperative oncology group performance status (ECOG PS ≥2), higher lactate dehydrogenase, bone marrow involvement, more frequent B symptoms, higher MCL International Prognostic Index (MIPI ≥6.2), and were less likely to receive intensive induction therapy than long DTI group. The median progression-free survival (2.5 years vs 4.8 years, p<0.0001) and overall survival (7.8 years vs. 11.8 years, p<0.0001) were significantly inferior in the short DTI group than the long DTI cohort and remained significant for progression-free survival and overall survival in multivariable analysis. We show that the DTI is an important prognostic factor in patients newly diagnosed with MCL and is strongly associated with adverse clinical factors and poor outcomes. DTI should be reported in all the patients newly diagnosed with MCL who are enrolling in clinical trials and steps must be taken to ensure selection bias is avoided.

How I manage mantle cell lymphoma: indolent versus aggressive disease

Mantle cell lymphoma (MCL) is a mature B-cell lymphoma with a variable clinical course and historically poor prognosis. Management is challenging in part due to the heterogeneity of the disease course, with indolent and aggressive subtypes now well recognised. Indolent MCL is often characterised by a leukaemic presentation, SOX11 negativity and low proliferation index (Ki-67). Aggressive MCL is characterised by rapid onset widespread lymphadenopathy, extra-nodal involvement, blastoid or pleomorphic histology and high Ki-67. Tumour protein p53 (TP53) aberrations in aggressive MCL are recognised with clear negative impact on survival. Until recently, trials have not addressed these specific subtypes separately. With the increasing availability of targeted novel agents and cellular therapies, the treatment landscape is constantly evolving. In this review, we describe the clinical presentation, biological factors, and specific management considerations of both indolent and aggressive MCL and discuss current and potential future evidence which may help move to a more personalised approach.

Personalized approaches for treatment-naïve mantle cell lymphoma

INTRODUCTION

Mantle cell lymphoma (MCL) can have diverse disease presentations, which vary in aggressiveness and prognosis, and can occur in patients with varying ability to tolerate therapy. Additionally, the options for treatment of MCL have expanded rapidly in the last decade, translating to improved outcome for patients.

AREAS COVERED

We review the initial evaluation of patients with MCL, identifying disease- and patient-specific prognostic factors, along with personalized therapies for patients with MCL. Specific scenarios include indolent and limited-stage MCL, advanced-stage disease in transplant-eligible and ineligible patients, and high-risk TP53 mutant disease. Ongoing trials and future directions in MCL treatment are also highlighted.

EXPERT OPINION

Given the wide array of disease and patient presentations with MCL, a personalized therapeutic approach is needed to optimize outcomes. The best therapeutic strategy should incorporate disease prognostic factors, patient status and comorbidities, goals of care, and response to treatment.

Impact of Pre-transplant Induction Therapy on Outcomes of Patients Who Undergo Autologous Stem Cell Transplantation for Mantle Cell Lymphoma in First Complete Remission

Mantle cell lymphoma is a rare subtype of non-Hodgkin's lymphoma with poor prognosis and continue to be challenging to treat. The choice of first line induction regimen remains a topic of debate due paucity of clinical trials. We retrospectively evaluated 66 patients diagnosed with mantle cell lymphoma who achieved first complete response after induction chemotherapy followed by autologous stem cell transplant. Treatment groups were divided into low-intensity versus high-intensity regimens. Our data showed the intensity of induction regimen does not impact posttransplant outcomes of mantle cell lymphoma who underwent autologous stem cell transplant in first complete response.

Chronic lymphocytic leukaemia/small lymphocytic lymphoma and mantle cell lymphoma: from early lesions to transformation

The International Clinical Advisory Committee reviewed advances in our understanding of the clinicopathologic and biologic features of chronic lymphocytic leukaemia/small lymphocytic lymphoma, B-cell prolymphocytic leukaemia, and mantle cell lymphoma since the revised 4th edition of the WHO Classification of Tumours of the Haematopoietic and Lymphoid Tissues. Discussions amongst pathologists, clinicians, and molecular geneticists around these diseases focussed on incorporating new knowledge into the next classification system. In this manuscript, we review these disease entities and incorporate results of these deliberations, including advances in our understanding of early lesions and transformation.

Bendamustine in combination with ofatumumab as first line treatment for elderly patients with mantle cell lymphoma: a phase II risk-adapted design

This study evaluated ofatumumab (Ofa), an anti-CD20 monoclonal antibody, alone or with bendamustine (Benda), in transplant-ineligible patients with mantle cell lymphoma. Low-risk patients received Ofa monotherapy. Non-responders received subsequent treatment with Benda-Ofa. Six patients received Ofa monotherapy and 3 patients crossed over to Bend-Ofa. Twenty-four high-risk patients were initially treated with Benda-Ofa. The overall response rate for patients treated with Ofa monotherapy was 1/6 (17%) and 23/25 (92%) for patients treated with Benda-Ofa. With a median follow-up of 8.6 years, all Ofa patients progressed with a median progression-free survival (PFS) of 0.6 years (95% CI 0.31-NR) and remain alive. With a median follow-up of 6.3 years, Bend-Ofa treated patients had median PFS 2.5 years (95% CI 1.8-NR) and a median overall survival of 7.4 years (95% CI 5.8-NR). Benda-Ofa had a favorable adverse event profile and efficacy similar, but not clearly superior, to those reported for Benda-Rituximab.

The International Consensus Classification of Mature Lymphoid Neoplasms: a report from the Clinical Advisory Committee

Since the publication of the Revised European-American Classification of Lymphoid Neoplasms in 1994, subsequent updates of the classification of lymphoid neoplasms have been generated through iterative international efforts to achieve broad consensus among hematopathologists, geneticists, molecular scientists, and clinicians. Significant progress has recently been made in the characterization of malignancies of the immune system, with many new insights provided by genomic studies. They have led to this proposal. We have followed the same process that was successfully used for the third and fourth editions of the World Health Organization Classification of Hematologic Neoplasms. The definition, recommended studies, and criteria for the diagnosis of many entities have been extensively refined. Some categories considered provisional have now been upgraded to definite entities. Terminology for some diseases has been revised to adapt nomenclature to the current knowledge of their biology, but these modifications have been restricted to well-justified situations. Major findings from recent genomic studies have impacted the conceptual framework and diagnostic criteria for many disease entities. These changes will have an impact on optimal clinical management. The conclusions of this work are summarized in this report as the proposed International Consensus Classification of mature lymphoid, histiocytic, and dendritic cell tumors.

Molecular determinants of outcomes in relapsed or refractory mantle cell lymphoma treated with ibrutinib or temsirolimus in the MCL3001 (RAY) trial

Mantle cell lymphoma (MCL) is a rare, incurable lymphoma subtype characterized by heterogeneous outcomes. To better understand the clinical behavior and response to treatment, predictive biomarkers are needed. Using residual archived material from patients enrolled in the MCL3001 (RAY) study, we performed detailed analyses of gene expression and targeted genetic sequencing. This phase III clinical trial randomized patients with relapsed or refractory MCL to treatment with either ibrutinib or temsirolimus. We confirmed the prognostic capability of the gene expression proliferation assay MCL35 in this cohort treated with novel agents; it outperformed the simplified MCL International Prognostic Index in discriminating patients with different outcomes. Regardless of treatment arm, our data demonstrated that this assay captures the risk conferred by known biological factors, including increased MYC expression, blastoid morphology, aberrations of TP53, and truncated CCND1 3' untranslated region. We showed the negative impact of BIRC3 mutations/deletions on outcomes in this cohort and identified that deletion of chromosome 8p23.3 also negatively impacts survival. Restricted to patients with deletions/alterations in TP53, ibrutinib appeared to abrogate the deleterious impact on outcome. These data illustrate the potential to perform a molecular analysis of predictive biomarkers on routine patient samples that can meaningfully inform clinical practice.

Prognostic value and computer image analysis of p53 in mantle cell lymphoma

P53 prognostic cut-off values differ between studies of mantle cell lymphoma (MCL), and its immunohistochemistry (IHC) interpretation is still based on semiquantitative estimation, which might be inaccurate. This study aimed to investigate the optimal cut-off value for p53 in predicting prognosis of patients with MCL and the possible use of computer image analysis to identify the positive rate of p53. We calculated p53 positive rate using QuPath software and compared it with the data obtained by manual counting and semiquantitative estimation. Survival curves were generated by using the Youden index and the Kaplan-Meier method. The chi-squared (χ2) test was used to compare MIPI, Ann Arbor stage, and cell morphology with p53. Spearman rank correlation test and Bland-Altman analysis were used to compare manual counting, computer image analysis and semiquantitative estimation, as well as the consistency between different observers. The optimal cut-off value of p53 for predicting prognosis was 20% in MCL patients. Patients with p53 ≥ 20% had a significantly worse overall survival (OS) than those with p53 < 20% (P < 0.0001). MCL patients with MIPI intermediate to high risk, Ann Arbor stage III-IV, and blastoid/pleomorphic variant cell morphology had more p53 ≥ 20%. There was a strong correlation between computer image analysis and manual counting of p53 from the same areas in MCL tissues (Spearman's rho = 0.966, P < 0.0001). The results of computer analysis are completely consistent between observers, and computer image analysis of Ki-67 can predict the prognosis of MCL patients. MCL patients with p53 ≥ 20% had a shorter OS and a tendency for MIPI intermediate to high risk, Ann Arbor stage III-IV, and blastoid/pleomorphic variant. Computer image analysis could determine the actual positive rate of p53 and Ki-67 and is a more attractive alternative than semiquantitative estimation in MCL.

Bendamustine or high-dose cytarabine-based induction with rituximab in transplant-eligible mantle cell lymphoma

The objective of this study was to explore differences in outcomes between first-line R-B and R-CHOP/R-DHAP in transplant-eligible patients with MCL. A population-based cohort of 97 patients aged 18-65 years with stage II-IV MCL, consecutively treated with R-B was retrospectively identified at BC Cancer. Baseline characteristics, response rates, and outcomes were compared to the cohort of 232 MCL patients randomized to the R-CHOP/R-DHAP arm of the MCL Younger trial. The primary aim was to estimate the hazard ratio (HR) of the progression-free survival (PFS) comparison between both groups, adjusted for MCL International Prognostic Index (MIPI), Ki67 index, and blastoid/pleomorphic morphology. Secondary endpoints included response rate, event free survival, overall survival, and time to next treatment. Ann Arbor stage, lactate dehydrogenase, MIPI, blastoid morphology, and MCL35 assignments were similar between both groups. The overall response rate (ORR) to R-B was 90% (54% complete response [CR]); 77% of patients proceeded to autologous stem cell transplantation (ASCT) and 78% received maintenance rituximab (MR). The ORR to R-CHOP/R-DHAP was 94% (54% CR); 78% proceeded to ASCT and 2% received MR. There were no differences in PFS in unadjusted (HR 0.87 [95% CI 0.53-1.41], p=0.56) or adjusted (HR 0.79 [95% CI 0.45-1.37], p=0.40) comparisons. There were no clear differences in secondary endpoints in unadjusted or adjusted analyses. This retrospective adjusted comparison of two independent cohorts of younger patients with MCL suggests that R-B with ASCT and maintenance rituximab is a feasible and effective first-line treatment, with outcomes comparable to R-CHOP/R-DHAP with ASCT.

Deep Neural Networks and Machine Learning Radiomics Modelling for Prediction of Relapse in Mantle Cell Lymphoma

Simple Summary

Mantle cell lymphoma (MCL) is an aggressive lymphoid tumour with a poor prognosis. There exist no routine biomarkers for the early prediction of relapse. Our study compared the potential of radiomics-based machine learning and 3D deep learning models as non-invasive biomarkers to risk-stratify MCL patients, thus promoting precision imaging in clinical oncology.

Abstract

Mantle cell lymphoma (MCL) is a rare lymphoid malignancy with a poor prognosis characterised by frequent relapse and short durations of treatment response. Most patients present with aggressive disease, but there exist indolent subtypes without the need for immediate intervention. The very heterogeneous behaviour of MCL is genetically characterised by the translocation t(11;14)(q13;q32), leading to Cyclin D1 overexpression with distinct clinical and biological characteristics and outcomes. There is still an unfulfilled need for precise MCL prognostication in real-time. Machine learning and deep learning neural networks are rapidly advancing technologies with promising results in numerous fields of application. This study develops and compares the performance of deep learning (DL) algorithms and radiomics-based machine learning (ML) models to predict MCL relapse on baseline CT scans. Five classification algorithms were used, including three deep learning models (3D SEResNet50, 3D DenseNet, and an optimised 3D CNN) and two machine learning models based on K-nearest Neighbor (KNN) and Random Forest (RF). The best performing method, our optimised 3D CNN, predicted MCL relapse with a 70% accuracy, better than the 3D SEResNet50 (62%) and the 3D DenseNet (59%). The second-best performing method was the KNN-based machine learning model (64%) after principal component analysis for improved accuracy. Our optimised CNN developed by ourselves correctly predicted MCL relapse in 70% of the patients on baseline CT imaging. Once prospectively tested in clinical trials with a larger sample size, our proposed 3D deep learning model could facilitate clinical management by precision imaging in MCL.

Evolving frontline immunochemotherapy for mantle cell lymphoma and the impact on survival outcomes

Because there have been a dvances in frontline treatment for mantle cell lymphoma (MCL) over the last 2 decades, we sought to characterize the changes in frontline treatment patterns and their association with outcomes. Patients with newly diagnosed MCL from September 2002 through June 2015 were enrolled in a prospective cohort study, and clinical characteristics, treatment, and clinical outcomes were compared between patients diagnosed from 2002 to 2009 (Era 1) compared with 2010 to 2015 (Era 2). Patient age, sex, and simplified MCL International Prognostic Index (sMIPI) score were similar between the 2 groups. In patients age 65 years or younger, there was less use of rituximab plus hyperfractionated cyclophosphamide, vincristine, doxorubicin, and dexamethasone (R-Hyper-CVAD) (16.1% vs 8.8%) but more use of rituximab plus maximum-strength cyclophosphamide, doxorubicin, vincristine, and prednisone (R-maxi-CHOP) alternating with rituximab plus high-dose cytarabine (R-HiDAC), also known as the Nordic regimen, and R-CHOP alternating with rituximab plus dexamethasone, high-dose cytarabine, and cisplatin (R-DHAP) (1.1% vs 26.4%) and less use of R-CHOP or R-CHOP-like regimens (64.5% vs 35.2%) but more use of R-bendamustine (0% vs 12.1%) in Era 2 (P < .001). These changes were associated with improved event-free survival (EFS; 5-year EFS, 34.3% vs 50.0%; P = .010) and overall survival (OS; 5-year OS, 68.8% vs 81.6%; P = .017) in Era 2. In patients older than age 65 years, there was less use of R-CHOP or R-CHOP-like therapy (39.0% vs 14.3%) and nonstandard systemic therapy (36.6% vs 13.0%) but more use of R-bendamustine (0% vs 49.4%). These changes were associated with a trend for improved EFS (5-year EFS, 25.4% vs 37.5%; P = .051) in Era 2. The shift from R-CHOP or R-CHOP-like regimens to R-bendamustine was associated with improved EFS (5-year EFS, 25.0% vs 44.6%; P = .008) in Era 2. Results from this prospective cohort study provide critical real-world evidence for improved outcomes with evolving frontline patterns of care in patients with MCL.

Initial Treatment Patterns and Survival Outcomes of Mantle Cell Lymphoma Patients Managed at Chinese Academic Centers in the Rituximab Era: A Real-World Study

Purpose

The aim of the study was to delineate the disease characteristics, the initial treatment patterns, and survival in patients with mantle cell lymphoma (MCL) managed in the real world.

Methods

Data of 518 MCL patients from 5 major Chinese Hematology Centers in the period from 2007 to 2017 were retrospectively analyzed.

Results

The median age was 58 years. Of the patients, 88.6% had Eastern Cooperative Oncology Group Performance Status (ECOG PS) 0–1 and 80.7% had advanced-stage disease. Ki67 expression was <30% in 39.6% of the patients, and 43.2% of patients were categorized into a low-risk group based on the Mantle Cell Lymphoma International Prognostic Index (MIPI) scoring system. Overall, 73.4% of the patients received rituximab as their first-line therapy. The most commonly used chemotherapy was the CHOP-like (cyclophosphamide, hydroxydaunomycin, oncovin, and prednisone) regimen (45.2%), followed by high-dose cytarabine-containing chemotherapy (31.3%) and bendamustine (3.3%). Of the patients, 13.7% (n = 71) underwent consolidative autologous stem cell transplantation (ASCT), and 19.3% (n = 100) received novel agents containing first-line regimens. With a median follow-up time of 52 months, the 3- and 5-year overall survival (OS) rates were 73.7% and 61.4%, respectively. Age ≤60 years, ECOG PS 0–1, stages I–II, normal lactate dehydrogenase (LDH), absence of bone marrow involvement, Ki67 <30%, and lower-risk IPI/MIPI scores were significantly associated with improved OS (p < 0.05). The inclusion of rituximab improved the 5-year OS, with borderline significance (62.5% vs. 55.2%, p = 0.076). High-dose cytarabine-containing chemotherapy showed significant clinical benefit in 5-year OS (72.1% vs. 55.9%, p = 0.010). Patients with ASCT had better 5-year OS in the younger (≤60 years) age group (87.2% vs. 64.8%, p = 0.002).

Conclusion

This large retrospective dataset unequivocally confirmed the survival advantage afforded by cytarabine-containing regimen and ASCT in a first-line setting under real-world management in the rituximab era.

Ibrutinib in Combination With Rituximab for Indolent Clinical Forms of Mantle Cell Lymphoma (IMCL-2015): A Multicenter, Open-Label, Single-Arm, Phase II Trial

The need for an individualized management of indolent clinical forms in mantle cell lymphoma (MCL) is increasingly recognized. We hypothesized that a tailored treatment with ibrutinib in combination with rituximab (IR) could obtain significant responses in these patients.

Early Relapse Identifies MCL patients with Inferior Survival after Intensive or Less Intensive Frontline Therapy

POD<24 months was associated with inferior survival among patients with MCL after both intensive and less intensive frontline treatment.

Patients with POD<6 months or progressive disease after frontline treatment had the highest risk of early mortality.

Although an expanding array of effective treatments has resulted in recent improvement in survival of patients with mantle cell lymphoma (MCL), outcomes remain heterogeneous, and identification of prognostic factors remains a priority. We assessed the prognostic impact of time to progression of disease (POD) after first-line therapy among 455 patients with relapsed MCL. Patients were categorized by duration of first remission as PRF/POD6, defined as progressive disease during induction or POD within 6 months of diagnosis (n = 65; 14%); POD6-24, defined as POD between 6 and 24 months after diagnosis (n = 153; 34%); and POD>24, defined as POD >24 months after diagnosis (n = 237; 53%). The median overall survival from POD (OS2) was 1.3 years (95% confidence interval [CI], 0.9-2.4) for patients with PRF/POD6, 3 years (95% CI, 2-6.8) for those with POD6-24, and 8 years (95% CI, 6.2-NR) for those with POD>24. Median OS2 was inferior in patients with early POD (defined as PRF/POD6 or POD6-24) after both intensive and less intensive frontline treatment. The prognostic performance of time until POD was replicated in an independent cohort of 245 patients with relapsed MCL, with median OS2 of 0.3 years (95% CI, 0.1-0.5) for PRF/POD6, 0.8 years (95% CI, 0.6-0.9) for POD6-24, and 2.4 years (95% CI 2.1-2.7) for POD>24. Early POD is associated with inferior OS2 in patients with relapsed MCL, identifying a high-risk population for future prospective studies.

Prognostic Significance of Lactate Dehydrogenase in Patients Undergoing Surgical Resection for Laryngeal Squamous Cell Carcinoma

The aim is to estimate the prognostic value of lactate dehydrogenase (LDH) in patients undergoing surgical resection for laryngeal squamous cell carcinoma (LSCC). A total of 640 resected LSCC patients were included. Preoperative lactate dehydrogenase (LDH) was assessed. Kaplan-Meier survival analysis and Cox regression analysis were conducted for overall survival (OS) and recurrence-free survival (RFS). Kaplan-Meier analysis, univariate analysis and multivariate analysis demonstrated significant prognostic value for preoperative LDH. Although LDH was predictor of OS, it failed to be a predictor of RFS. The univariate HR and 95% CI of LDH were 0.484 and 0.357-0.658 (P < 0.0001). The multivariate analysis showed that LDH (HR = 0.518, 95% CI: 0.380-0.705, p < 0.0001) was related to OS. Elevated preoperative LDH >132 IU/L was significantly associated with better survival. Preoperative LDH might be an independent prognostic marker of OS in LSCC patients undergoing surgical resection.

Advances in Classification and Treatment of Non-Hodgkin Lymphoma: Mantle Cell

Mantle cell lymphoma is a rare, aggressive, and largely incurable form of non-Hodgkin lymphoma. There are a number of well-characterized prognostic features but nothing that can help guide therapy. Treatment with chemotherapy is generally effective in the short term, but relapse is inevitable and subsequent treatment is challenging. The use of Bruton tyrosine kinase inhibitors, however, has transformed practice. These agents are highly active in relapsed disease and are very well-tolerated drugs. Chemotherapy-free combinations using Bruton tyrosine kinase inhibitors look very exciting and will likely evolve to be part of frontline care in the future.

Leukemic Variant of Mantle Cell Lymphoma: Clinical Presentation and Management

PURPOSE OF REVIEW

This review summarizes the unique presentation and management of the leukemic variant of mantle cell lymphoma (LV-MCL, also referred to as non-nodal MCL) and highlights the biologic and clinical differentiation from classical mantle cell lymphoma (cMCL) in biomarker expression, clinical features, prognosis, disease course, and treatment.

RECENT FINDINGS

Several studies have evaluated the gene expression profile of mantle cell lymphoma, differentiating LV-MCL from cMCL. The typical immunophenotypic profile is CD5-positive, SOX 11-negative, CD23-low, CD200-low, and cyclin D1 overexpressed. LV-MCL commonly has mutated immunoglobulin heavy chain variable region genes. Data on treatment of LV-MCL is limited to retrospective analyses; the ideal treatment for these patients is unknown although many have a clinically indolent, asymptomatic presentation and often may be observed for an extended period without active treatment. LV-MCL is a clinically and biologically distinct entity. Clinically, it must be distinguished from chronic lymphocytic leukemia and cMCL. Future prospective, randomized clinical trials are required to optimize management, define the initial treatment, and appropriately sequence treatment modalities.

Exploiting gene mutations and biomarkers to guide treatment recommendations in mantle cell lymphoma

INTRODUCTION

While there has been an improvement in the treatment of mantle cell lymphoma (MCL) in both median progression-free survival (PFS; >7-8 years) and overall survival (OS; >10-12 years), patients with high-risk features such as high risk MIPI (mantle cell international prognostic index), high Ki-67 (≥30%), or blastoid variants still carry poor outcome with a median OS of 3 years. Furthermore, patients with high-risk molecular features, such as TP53 mutations, show dismal outcome, with a median OS of 1.8 years, regardless of therapy used. Further studies have led to the development of six novel drugs approved for the treatment of relapse/refractory (R/R) MCL, leading to improved survival even in refractory or high-risk patients.

AREAS COVERED

This review covers clinical biological and molecular features that impact MCL outcome with current standards. Beyond the recognition of separate subentities, we review how high-risk molecular features have paved the way towards a new paradigm away from chemoimmunotherapy.

EXPERT OPINION

Progress in novel therapies and in routine diagnostics, particularly next-generation sequencing (NGS), support the development of new treatment strategies, not based on the dose intensity/age dichotomy, which may prevent the need for chemotherapy and improve outcome across MCL including in high-risk subsets.

Intensive induction regimens after deferring initial therapy for mantle cell lymphoma are not associated with improved survival

INTRODUCTION

While most patients with mantle cell lymphoma (MCL) receive therapy shortly after diagnosis, a subset of patients with indolent-behaving disease can safely defer treatment. In this subgroup, we evaluated the importance of treatment intensity in patients with MCL who defer initial therapy.

METHODS

Out of 1134 patients with MCL from 12 academic centers, we analyzed 219 patients who initiated therapy at least 90 days after diagnosis. Patients who received induction with high-dose cytarabine and/or autologous stem cell transplantation (ASCT) in first remission were considered to have received intensive therapy (n = 88) while all other approaches were non-intensive (n = 131).

RESULTS

There was no difference in progression-free (PFS; P = .224) or overall survival (OS; P = .167) in deferred patients who received non-intensive vs. intensive therapy. Additionally, univariate and multivariate Cox proportional hazards models were performed for PFS and OS. Treatment at an academic center (HR 0.43, P = .015) was associated with improved OS in both univariate and multivariate models, while intensity of treatment was not associated with improved OS in either model.

CONCLUSIONS

These results indicate that intensified initial treatment is not associated with improved survival after deferring initial therapy, although prospective studies are needed to determine which of these patients with MCL may benefit from intensive therapy.

Real World Treatment Practices for Mantle Cell Lymphoma in Japan: An Observational Database Research Study (CLIMBER-DBR)

Mantle cell lymphoma (MCL) accounts for approximately 3% of all cases of malignant lymphoma in Japan. The CLIMBER-DBR (Treatment practices and patient burden in chronic lymphocytic leukemia and mantle cell lymphoma patients in the real world: An observational database research in Japan) study examined the clinical characteristics, treatment patterns, and healthcare resource utilization of MCL in a real-world clinical setting in Japan. Using the Japanese Medical Data Vision database, we extracted data for 1130 patients with MCL (ICD-10 code C83.1) registered between March 1, 2013 and February 28, 2018. The date of first MCL diagnosis was taken as the index date. The mean (standard deviation) age, body weight, and modified Charlson Comorbidity Index were 71.4 (10.9) years, 58.3 (11.7) kg, and 1.9 (1.6), respectively, and 24.6% were ≤65 years old. The median follow-up period was 654 days (first–third quartile 290.5–1049 days). A total of 802 patients (71.0%) underwent first-line treatment. The most common first-line treatment was bendamustine/rituximab (BR; 27.8%), followed by rituximab/cyclophosphamide/doxorubicin/vincristine/prednisolone (R-CHOP; 15.6%) and rituximab/tetrahydropyranyl-adriamycin/cyclophosphamide/vincristine/prednisolone (R-THP-COP; 6.5%). The median (95% confidence interval) times to initial (first-line), second-line, and third-line treatments were 45 (36–62), 687 (624–734), and 1188 (1099–1444) days, respectively. Treatment practices for MCL in Japan are consistent with trends observed in Western countries. Our study can serve as a benchmark to assess future MCL treatments in Japan.

Bendamustine and rituximab as induction therapy in both transplant-eligible and -ineligible patients with mantle cell lymphoma

Rituximab-containing chemotherapy regimens constitute standard first-line therapy for mantle cell lymphoma (MCL). Since June 2013, 190 patients ≥18 years of age with MCL in British Columbia have been treated with bendamustine and rituximab (BR). The overall response rate to BR was 88% (54% complete response). Of these, 61 of 89 patients (69%) aged ≤65 years received autologous stem cell transplantation and 141 of 190 patients (74%) from the entire cohort received maintenance rituximab. Twenty-three patients (12%) had progressive disease, associated with high risk per the Mantle Cell Lymphoma International Prognostic Index (MIPI), Ki-67 ≥50%, and blastoid/pleomorphic histology. Outcomes were compared with a historical cohort of 248 patients treated with rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP; January 2003 to May 2013). Treatment with BR was associated with significant improvements in progression-free survival (PFS), but not overall survival (OS), compared with R-CHOP in the whole cohort (3-year PFS, 66% BR vs 51% R-CHOP, P = .003; 3-year OS, 73% BR vs 66% R-CHOP, P = .054) and in those >65 years of age (3-year PFS, 56% BR vs 35% R-CHOP, P = .001; 3-year OS, 64% BR vs 55% R-CHOP, P = .063). Outcomes in transplanted patients were not statistically significantly different compared with R-CHOP (3-year PFS, 85% BR vs 76% R-CHOP, P = .135; 3-year OS, 90% BR vs 88% R-CHOP, P = .305), although in multivariate analyses, treatment with BR was associated with improved PFS (hazard ratio, 0.40 [95% confidence interval, 0.17-0.94]; P = .036) but not OS. BR is an effective first-line option for most patients with MCL, however, outcomes are suboptimal for those with high-risk features and further studies integrating novel agents are warranted.

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.

Cellular Therapies for Mantle Cell Lymphoma

Mantle cell lymphoma (MCL) is a subtype of B cell non-Hodgkin lymphoma characterized by a heterogeneous clinical presentation. Patients who demonstrate an objective response to induction therapy(ies) and are eligible for intensive therapies are offered an autologous hematopoietic cell transplant (HCT) as front-line consolidation followed by rituximab maintenance. Allogeneic HCT is an option for younger and fit patients with high-risk disease or in patients who have relapsed after autologous HCT. Recent advances in T cell engineering brought chimeric antigen receptor T cell (CAR T) therapy from the bench to the bedside, with brexucabtagene autoleucel being the first CAR T product approved by the US Food and Drug Administration for use in relapsed/refractory MCL. In this comprehensive review, we summarize the literature on available cellular therapies for MCL and present a treatment algorithm that incorporates HCT, autologous or allogeneic, and CAR T therapies.

Clinical characteristics and outcomes of primary versus secondary gastrointestinal mantle cell lymphoma

Primary gastrointestinal (GI) mantle cell lymphoma (MCL) is rare and the optimal management is unknown. We reviewed 800 newly diagnosed MCL cases and found 22 primary (2.8%) and 79 (9.9%) secondary GI MCL cases. Age, sex, and performance status were similar between primary and secondary cases. Secondary cases had more elevations in lactate dehydrogenase (28% vs 0%, P = 0.03) and a trend for a higher MCL international prognostic index (P = 0.07). Observation or local therapy was more common for primary GI MCL (29% vs 8%, P < 0.01), and autologous stem-cell transplant was more common for secondary GI MCL (35% vs 14%, P < 0.05). The median follow-up was 85 months. Primary and secondary GI MCL had similar 5-year progression-free survival (PFS) (30% vs 28%, P = 0.59) and overall survival (OS) (65% vs 66%, P = 0.83). The extent of GI involvement in primary GI MCL affected treatment selection but not outcome, with a 5-year PFS of 43% vs 14% vs 31% (P = 0.48) and OS of 57% vs 71% vs 69% (P = 0.54) in cases with single lesion vs multiple lesions in 1 organ vs multiple lesions in ≥2 organs. Less aggressive frontline treatment for primary GI MCL is reasonable. It is unknown whether more aggressive treatment can result in improved outcomes.

Primary GI MCL is rare. These patients tend to be treated less aggressively in the frontline setting yet have similar outcomes as those with secondary GI MCL.

Less aggressive frontline treatment for primary GI MCL is reasonable given decent outcome, although it is unknown whether more aggressive treatment can result in improved outcomes.

Coding and noncoding drivers of mantle cell lymphoma identified through exome and genome sequencing

Mantle cell lymphoma (MCL) is an uncommon B-cell non-Hodgkin lymphoma (NHL) that is incurable with standard therapies. The genetic drivers of this cancer have not been firmly established, and the features that contribute to differences in clinical course remain limited. To extend our understanding of the biological pathways involved in this malignancy, we performed a large-scale genomic analysis of MCL using data from 51 exomes and 34 genomes alongside previously published exome cohorts. To confirm our findings, we resequenced the genes identified in the exome cohort in 191 MCL tumors, each having clinical follow-up data. We confirmed the prognostic association of TP53 and NOTCH1 mutations. Our sequencing revealed novel recurrent noncoding mutations surrounding a single exon of the HNRNPH1gene. In RNA-seq data from 103 of these cases, MCL tumors with these mutations had a distinct imbalance of HNRNPH1 isoforms. This altered splicing of HNRNPH1 was associated with inferior outcomes in MCL and showed a significant increase in protein expression by immunohistochemistry. We describe a functional role for these recurrent noncoding mutations in disrupting an autoregulatory feedback mechanism, thereby deregulating HNRNPH1 protein expression. Taken together, these data strongly imply a role for aberrant regulation of messenger RNA processing in MCL pathobiology.

Is Limited-Stage Mantle Cell Lymphoma Curable and How Is It Best Managed?

Limited-stage (stage I-II) mantle cell lymphoma (MCL) is rarely encountered. There is no standard approach to treatment and available data to guide management decisions mainly are retrospective studies. A thorough staging evaluation, including positron emission tomography/computed tomography, bone marrow biopsy, and gastrointestinal evaluation, should be completed because disseminated disease is common. Radiation therapy is effective for local control, and, although prolonged remission can be achieved, distant relapses are common and there are insufficient data to say that patients can be cured using this treatment. This article reviews literature pertaining to management of patients with limited-stage MCL and discusses approach to treatment.

Watch and Wait in Mantle Cell Lymphoma

Mantle cell lymphoma (MCL) is a biologically heterogeneous disease, and patients may experience a clinical course ranging from indolent to very aggressive. Observational studies suggest that a subset of patients can be safely observed for a period of months to years from initial diagnosis without adversely impacting their outcomes. However, identification of candidates for the "watch and wait" approach remains challenging because selection criteria are not well-defined. Studies that prospectively stratify patients on the basis of MCL biology and disease risk will be informative, and patients with indolent MCL may be ideal candidates for frontline clinical trials exploring novel therapies.

Mantle Cell Lymphoma: Which Patients Should We Transplant?

PURPOSE OF REVIEW

Mantle cell lymphoma is a CD5+ non-Hodgkin lymphoma associated with suboptimal outcome. Young, fit patients are generally offered intensive induction followed by autologous hematopoietic cell transplantation (AHCT) in first remission. Some patients may not benefit from this strategy.

RECENT FINDINGS

Recent studies have investigated the role of AHCT in the modern era. First, an analysis of the National Cancer Database demonstrated improved progression-free survival (PFS) for consolidative AHCT. Second, a multi-center study associated consolidative AHCT with improved PFS even after propensity-weighted analysis. Improved overall survival (OS) for certain subgroups was suggested. Third, patients with p53 mutations derive little benefit from AHCT. Finally, retrospective series suggest certain high-risk patients may be considered for allogenic HCT. AHCT consolidation in first remission is associated with improved PFS even after adjustment for disease severity. An overall survival benefit has not been definitively shown. Patients with p53 mutations should be treated with novel agents.

Mantle cell lymphoma

MCL is a well-characterized generally aggressive lymphoma with a poor prognosis. However, patients with a more indolent disease have been reported in whom the initiation of therapy can be delayed without any consequence for the survival. In 2017 the World Health Organization updated the classification of MCL describing two main subtypes with specific molecular characteristics and clinical features, classical and indolent leukaemic nonnodal MCL. Recent research results suggested an improving outcome of this neoplasm. The addition of rituximab to conventional chemotherapy has increased overall response rates, but it did not improve overall survival compared to chemotherapy alone. The use of intensive frontline therapies including rituximab and consolidation with autologous stem cell transplantation ameliorated response rate and prolonged progression-free survival in young fit patients, but any impact on survival remains to be proven. Furthermore, the optimal timing, cytoreductive regimen and conditioning regimen, and the clinical implications of achieving a disease remission even at molecular level remain to be elucidated. The development of targeted therapies as the consequence of better understanding of pathogenetic pathways in MCL might improve the outcome of conventional chemotherapy and spare the toxicity of intense therapy in most patients. Cases not eligible for intensive regimens, may be considered for less demanding therapies, such as the combination of rituximab either with CHOP or with purine analogues, or bendamustine. Allogeneic SCT can be an effective option for relapsed disease in patients who are fit enough and have a compatible donor. Maintenance rituximab may be considered after response to immunochemotherapy as the first-line strategy in a wide range of patients. Finally, since the optimal approach to the management of MCL is still evolving, it is critical that these patients are enrolled in clinical trials to identify the better treatment options.

Mantle Cell Lymphoma of Mucosa-Associated Lymphoid Tissue: A European Mantle Cell Lymphoma Network Study

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While classical nodal mantle cell lymphoma (cMCL) is often associated with involvement of multiple extranodal sites, isolated extranodal disease (ED) at the time of diagnosis is a rare event; data on the outcome of these forms are lacking. On behalf of the European MCL Network, we conducted a retrospective analysis on the clinical characteristics and outcomes of MCL presenting with isolated or predominant ED (MALT MCL). We collected data on 127 patients with MALT MCL diagnosed from 1998 to 2015: 78 patients (61%) were male with a median age of 65 years. The involved sites include: upper airways + Waldeyer ring (40; 32%), gastrointestinal tract (32; 25%), ocular adnexa (17; 13%), oral cavity and salivary glands (17; 13%) and others (13; 1%); 7 patients showed multiple extranodal sites. The median follow-up was 80 months (range: 6–182), 5-year progression-free survival (PFS) was 45% (95% CI: 35–54) and 5-year overall survival (OS) was 71% (95% CI: 62–79). In an explorative setting, we compared MALT MCL with a group of 128 cMCL patients: MALT MCL patients showed a significantly longer PFS and OS compared with nodal cMCL; with a median PFS of 4.5 years vs 2.8 years (p = 0.001) and median OS of 9.8 years vs 6.9 years (p = 0.018), respectively. Patients with MALT MCL at diagnosis showed a more favorable prognosis and indolent course than classical nodal type. This clinical variant of MCL should be acknowledged to avoid possible over-treatment.

Proapoptotic protein BIM as a novel prognostic marker in mantle cell lymphoma

Mantle cell lymphoma (MCL) is an aggressive B-cell lymphoma. Numerous studies have demonstrated many genetic aberrations in MCL in addition to the characteristic t(11:14), including frequent biallelic deletions of Bim, a proapoptotic member of the BCL-2 family. In mice, Bim deletion coupled with cyclin D1 overexpression generates pathologic and molecular features of human MCL. Since the regulation of apoptosis is crucial in MCL pathogenesis, we hypothesize that BIM expression may be associated with tumor cell survival. Clinical data and tissue from 100 nodal MCL cases between 1988 and 2009 were collected from three large academic medical centers. The average patient age of our MCL cohort was 65.5 years old (range, 42-97) with a 2:1 male to female ratio. Immunohistochemistry was performed with a validated anti-BIM antibody. Patients were separated into low and high BIM-expressing categories with a cutoff of 80%. As expected for a proapoptotic tumor suppressor, patients with high BIM expression were less likely to have progressive disease and more likely to have a complete response (P = .022). In addition, high BIM-expressing MCL tumors revealed a trend toward increased overall survival with this trend persisting in sub-analysis of Ann Arbor stages III and IV. No correlation between BIM expression, Ki-67 index, and MIPI score was observed, suggesting a role for BIM as a novel independent prognostic factor. While BIM is only one member of a complex family of apoptosis-regulating proteins, these findings may yield clinically relevant information for the prognosis and therapeutic susceptibility of MCL.

Optimal management of mantle cell lymphoma in the primary setting

Introduction: The management of mantle cell lymphoma (MCL) has significantly improved since the use of intensified induction and autologous stem cell transplant consolidation. Evolving developments in minimal residual disease detection and novel agent therapy are now challenging this frontline treatment paradigm. Areas covered: This review discusses both the established role of induction and transplant consolidation in MCL, followed by evolving concepts in the use of novel agents in the frontline setting, and the use of minimal residual disease as a driver of MCL management. Expert opinion: In an era of novel agents and improved biologic understanding of MCL, our goal for frontline management should evolve toward personalized therapy for individual patients to maximize efficacy and survival whilst minimizing treatment-related toxicities.

The modern approach to mantle cell lymphoma

Mantle Cell Lymphoma is a rare and generally aggressive form of non Hodgkin lymphoma. Our understanding of the pathophysiology of this disease is improving and whilst risk factors are understood, treatments are not yet tailored towards these. The treatment algorithm in the front line is well established for older and younger patients and observation is the norm for a subset of patients although these are not well characterised as yet. In the relapse setting the role of novel agents, especially the BTK inhibitors is becoming established and combination approaches look promising. Trials are beginning to challenge the role of chemotherapy against the novel agents especially as part of front line therapy. As a consequence it is likely we will see a paradigm shift in the management of this disease in the next few years.

Mantle cell lymphoma: 2019 update on the diagnosis, pathogenesis, prognostication, and management

Unprecedented advances in our understanding of the pathobiology, prognostication, and therapeutic options in mantle cell lymphoma (MCL) have taken place in the last few years. Heterogeneity in the clinical course of MCL-indolent vs aggressive-is further delineated by a correlation with the mutational status of the variable region of immunoglobulin heavy chain, methylation status, and SOX-11 expression. Cyclin-D1 negative MCL, in situ MCL neoplasia, and impact of the karyotype on prognosis are distinguished. Apart from Ki-67% and morphology pattern (classic vs blastoid/pleomorphic), the proliferation gene signature has helped to further refine prognostication. Studies focusing on mutational dynamics and clonal evolution on Bruton's tyrosine kinase (BTK) inhibitors (ibrutinib, acalabrutinib) and/or Bcl2 antagonists (venetoclax) have further clarified the prognostic impact of somatic mutations in TP53, BIRC3, CDKN2A, MAP3K14, NOTCH2, NSD2, and SMARCA4 genes. In therapy, long-term follow-up on chemo-immunotherapy studies has demonstrated durable remissions in some patients; however, long-term toxicities, especially from second cancers, are a serious concern with chemotherapy. The therapeutic options in MCL are constantly evolving, with dramatic responses from nonchemotherapeutic agents (ibrutinib, acalabrutinib, and venetoclax). Chimeric antigen receptor therapy and combinations of nonchemotherapeutic agents are actively being studied and our focus is shifting toward making the treatment of MCL chemotherapy-free. Still, MCL remains incurable. The following aspects of MCL continue to pose a challenge: disease transformation, role of the cytokine-microenvironmental milieu, incorporation of positron emission tomography-computerized tomography imaging, minimal residual disease in the prognosis, circulating tumor DNA testing for clonal evolution, predicting resistance to BTK inhibitors, and optimal management of patients who progress on BTK/Bcl2 inhibitors. Next-generation clinical trials should incorporate nonchemotherapeutic agents and personalize the treatment based upon the genomic profile of individual patient. Recent advances in the field of MCL are reviewed.

Real world data as a key element in precision medicine for lymphoid malignancies: potentials and pitfalls

Molecular genetic studies of lymphoma have led to refinements in disease classification in the most recent World Health Organization update. Nevertheless, a 'one-size-fits-most' treatment strategy based on morphology remains widely used for lymphoma despite significant molecular heterogeneity within histopathologically-defined subtypes. Precision medicine aims to improve patient outcomes by leveraging disease- and patient-specific information to optimise treatment strategies, but implementation of precision medicine strategies is challenged by the biological diversity and rarity of lymphomas. In this review, we explore existing and emerging real-world data sources that can be used to facilitate the development of precision medicine strategies in lymphoma. We provide illustrative examples of the use of real-world analyses to refine treatment strategies, provide comparators for clinical trials, improve risk-stratification to identify patients with unmet clinical needs and describe long-term and rare toxicities.

Mantle Cell Lymphoma: Current and Emerging Treatment Strategies and Unanswered Questions

Mantle cell lymphoma (MCL) is biologically and clinically heterogeneous with no clear standard of care. Overexpression of cyclin D1 is a hallmark of MCL. Evolving characterization of other molecular drivers explain a variety of disease phenotypes. These molecular profiles challenge risk stratification techniques. TP53-deleted disease is associated with adverse outcomes. Frontline treatment programs include intensive chemoimmunotherapy and autologous stem cell transplantation. Minimal residual disease may change management of MCL and guide therapy. As commonly dysregulated pathways become enumerated, novel biologically targeted agents and their combinations have been developed that will increasingly replace older, more toxic, and less efficacious regimens.

Update on mantle cell lymphoma

Mantle cell lymphoma (MCL) is a rare subtype of non-Hodgkin lymphoma that is most commonly treated with combination chemo-immunotherapy at diagnosis because of the poor prognosis. More indolent presentations have been described including patients who can defer initial therapy without adverse impact on survival. The 2016 World Health Organization updated classification describes 2 major subtypes, classical and leukemic nonnodal MCL, each with unique molecular features and clinical presentations. Although there is no standard of care for MCL, aggressive chemo-immunotherapy regimens containing rituximab and cytarabine, followed by consolidation with autologous stem cell transplantation and maintenance rituximab, are the most used approach in young fit patients, and chemo-immunotherapy, followed by rituximab maintenance, is most commonly used in older patients. Despite the improvement in response durations with currently available therapies, patients will inevitably relapse. A number of targeted therapies are approved in the relapsed setting and are now under evaluation in combination with standard frontline therapy. Although the approval of ibrutinib changed the landscape of therapy for relapsed MCL, prognosis remains poor after progression on ibrutinib supporting the development of ibrutinib combinations to prolong response duration as well as the development of other novel agents for ibrutinib refractory disease. With ibrutinib being incorporated into initial therapy regimens, new options will be needed at relapse. Prognostic markers, such as minimal residual disease, have been shown to correlate independently with outcomes along with predicting relapse, with the potential to guide therapeutic decisions. The future treatment of MCL therapy will need to incorporate therapy based on risk-stratification and nonchemotherapeutic approaches.

Validation of the MCL35 gene expression proliferation assay in randomized trials of the European Mantle Cell Lymphoma Network

Mantle cell lymphoma (MCL) is still considered incurable and the course of the disease is highly variable. Established risk factors include the Mantle Cell Lymphoma International Prognostic Index (MIPI) and the quantification of the proliferation rate of the tumour cells, e.g. by Ki-67 immunohistochemistry. In this study, we aimed to validate the prognostic value of the gene expression-based MCL35 proliferation assay in patient cohorts from randomized trials of the European Mantle Cell Lymphoma Network. Using this assay, we analysed the gene expression proliferation signature in routine diagnostic lymph node specimens from MCL Younger and MCL Elderly trial patients, and the calculated MCL35 score was used to assign MCL patients to low (61%), standard (27%) or high (12%) risk groups with significantly different outcomes. We confirm here in our prospective clinical trial cohort of MCL patients, that the MCL35 assay is strongly prognostic, providing additional information to the Ki-67 index and the MIPI. Thus, this robust assay may assist in making treatment decisions or in devising risk-adapted prospective clinical trials in the future.

A gene signature that distinguishes conventional and leukemic nonnodal mantle cell lymphoma helps predict outcome

Mantle cell lymphoma (MCL) is an aggressive B-cell malignancy, but some patients have a very indolent evolution. This heterogeneous course is related, in part, to the different biological characteristics of conventional MCL (cMCL) and the distinct subgroup of leukemic nonnodal MCL (nnMCL). Robust criteria to distinguish these MCL subtypes and additional biological parameters that influence their evolution are not well defined. We describe a novel molecular assay that reliably distinguishes cMCL and nnMCL using blood samples. We trained a 16-gene assay (L-MCL16 assay) on the NanoString platform using 19 purified leukemic samples. The locked assay was applied to an independent cohort of 70 MCL patients with leukemic presentation. The assay assigned 37% of cases to nnMCL and 56% to cMCL. nnMCL and cMCL differed in nodal presentation, lactate dehydrogenase, immunoglobulin heavy chain gene mutational status, management options, genomic complexity, and CDKN2A/ATM deletions, but the proportion with 17p/TP53 aberrations was similar in both subgroups. Sequential samples showed that assay prediction was stable over time. nnMCL had a better overall survival (OS) than cMCL (3-year OS 92% vs 69%; P = .006) from the time of diagnosis and longer time to first treatment. Genomic complexity and TP53/CDKN2A aberrations predicted for shorter OS in the entire series and cMCL, whereas only genomic complexity was associated with shorter time to first treatment and OS in nnMCL. In conclusion, the newly developed assay robustly recognizes the 2 molecular subtypes of MCL in leukemic samples. Its combination with genetic alterations improves the prognostic evaluation and may provide useful biological information for management decisions.