Outcome of deferred initial therapy in mantle-cell lymphoma

Understanding the New WHO Classification of Lymphoid Malignancies: Why It's Important and How It Will Affect Practice

Improved delineation of lymphoid malignancy biology has prompted refinement of the 2008 World Health Organization (WHO) classification of hematopoietic and lymphoid tumors with a new framework introduced in 2016. This knowledge has provided valuable insights regarding management. Early clonal proliferations have been set apart given their limited potential for malignant dissemination. Increasing knowledge of molecular drivers of aggressive lymphomas has allowed subclassification and opportunity for clinical investigations to personalize therapy. New insights into T-cell pathophysiology has allowed grouping based on shared molecular and cellular features. This article will summarize the key changes in terms of diagnosis and histopathologic definitions, the impact of these changes on clinical management, and the challenges of future research in this field.

Optimizing therapy for mantle cell lymphoma

Most people with mantle cell lymphoma (MCL) present with diffuse adenopathy and benefit from early initiation of rituximab and high-dose cytarabine- or bendamustine-based therapies. Some patients, however, present with primarily nonnodal disease that can follow either an indolent or a rapidly progressive, treatment-resistant clinical course. Rarely, patients present with explosive disease that can be challenging to manage and often involves the central nervous system. New agents with improved therapeutic indices facilitate treatment while maintaining quality of life, but also present new complications at the time of treatment failure. Although uncommon presentations are not new to clinicians who treat MCL, the increasing clarity of underlying biology and prognostic implications may help us develop more specialized treatment strategies.

Current Approaches to Mantle Cell Lymphoma: Diagnosis, Prognosis, and Therapies

Mantle cell lymphoma (MCL) is a unique lymphoma subtype, both biologically and clinically. Virtually all cases are characterized by a common genetic lesion, t(11;14), resulting in overexpression of cyclin D1. The clinical course is moderately aggressive, and the disease is considered incurable. Considerable biologic and clinical heterogeneity exists, with some patients experiencing a rapidly progressive course, while others have disease that is readily managed. New tools exist for risk stratification and may allow for a more personalized approach in the future. Landmark studies have been completed in recent years and outcomes appear to be improving. Randomized clinical trials have clarified the role of high-dose cytarabine (Ara-C) for younger patients and have demonstrated a role for maintenance rituximab therapy. Multiple areas of uncertainty remain, however, and are the focus of ongoing research. This review focuses on (1) strategies to differentiate between aggressive and less aggressive cases, (2) understanding who should receive hematopoietic stem cell transplantation, and (3) the role for maintenance therapy in MCL.

Novel therapies for relapsed/refractory mantle cell lymphoma

Mantle cell lymphoma is an aggressive Non-Hodgkin's lymphoma that is considered incurable with standard therapies. Most patients treated with frontline immunochemotherapy relapse within a few years and do not usually respond to salvage chemotherapy. Persistent activation of the B-cell receptor pathway is critical to the pathogenesis of mantle cell lymphoma. Inhibition of Bruton's tyrosine kinase, an essential B-cell receptor pathway component with ibrutinib has shown clinical activity and has changed how MCL is treated in the relapsed/refractory setting. However, resistance to ibrutinib is common and response is limited. Novel agents targeting the B-cell receptor pathway along with therapies outside of the pathway will be reviewed in this article. Ongoing and future studies will better define how these agents should be utilized in the ever-changing treatment landscape of mantle cell lymphoma.

Whole body magnetic resonance in indolent lymphomas under watchful waiting: The time is now

ᅟ: The indolent non-Hodgkin lymphomas (i-NHLs) are characterised by 'indolent' clinical behaviour with slow growth and prolonged natural history. The watchful waiting (WW) strategy is a frequently employed treatment option in these patients. This implies a strict monitoring by imaging examinations, including 18F-fluorodeoxyglucose-positron emission tomography/computed tomography (18F-FDG-PET/CT) and CT. A major concern is radiation exposure due to regularly monitoring by conventional imaging procedures. Several studies have demonstrated the reliability of whole-body magnetic resonance imaging (WB-MRI) for lymphoma staging. WB-MRI could be useful for active surveillance in i-NHLs providing the suspect of disease progression that can be then confirmed by additional diagnostic procedures, including 18F-FDG-PET/CT. The directive 2013/59 by the European Union claims that if a radiation-free imaging technique allows obtaining the same diagnostic results, it should be invariably used. In this setting, WB-MRI may be considered a reasonable option in i-NHLs under WW, replacing imaging modalities that cause exposure to ionising radiations. This will help to reduce the cancer risk in i-NHL patients for whom chemo-/radiotherapy remain the usual treatment options following the usually long WW phase. The scientific community should raise the awareness of the risk of ionising radiations in i-NHLs and the emphasise the need for establishing the proper place of WB-MRI in lymphoma imaging.

KEY POINTS

• Watchful waiting is a reasonable option in patients with indolent non-Hodgkin lymphomas. • Imaging is crucial to monitor patients with indolent non-Hodgkin lymphomas. • CT and ¹⁸ F-FDG-PET/CT are commonly used, implying a substantial radiation exposure. • WB-MRI is highly reliable in lymphoma staging. • WB-MRI may be considered to monitor indolent non-Hodgkin lymphomas under watchful waiting.

Clinical utility of recently identified diagnostic, prognostic, and predictive molecular biomarkers in mature B-cell neoplasms

Genomic profiling studies have provided new insights into the pathogenesis of mature B-cell neoplasms and have identified markers with prognostic impact. Recurrent mutations in tumor-suppressor genes (TP53, BIRC3, ATM), and common signaling pathways, such as the B-cell receptor (CD79A, CD79B, CARD11, TCF3, ID3), Toll-like receptor (MYD88), NOTCH (NOTCH1/2), nuclear factor-κB, and mitogen activated kinase signaling, have been identified in B-cell neoplasms. Chronic lymphocytic leukemia/small lymphocytic lymphoma, diffuse large B-cell lymphoma, follicular lymphoma, mantle cell lymphoma, Burkitt lymphoma, Waldenström macroglobulinemia, hairy cell leukemia, and marginal zone lymphomas of splenic, nodal, and extranodal types represent examples of B-cell neoplasms in which novel molecular biomarkers have been discovered in recent years. In addition, ongoing retrospective correlative and prospective outcome studies have resulted in an enhanced understanding of the clinical utility of novel biomarkers. This progress is reflected in the 2016 update of the World Health Organization classification of lymphoid neoplasms, which lists as many as 41 mature B-cell neoplasms (including provisional categories). Consequently, molecular genetic studies are increasingly being applied for the clinical workup of many of these neoplasms. In this review, we focus on the diagnostic, prognostic, and/or therapeutic utility of molecular biomarkers in mature B-cell neoplasms.

Autologous Stem Cell Transplant: Still the Standard for Fit Patients With Mantle Cell Lymphoma

Mantle cell lymphoma is a relatively rare malignancy, comprising fewer than 10% of all non-Hodgkin lymphomas. It is a heterogeneous disease, and although most patients experience an aggressive clinical course, some have a more indolent disease and may not require immediate therapy. There are currently few reliable prognostic markers, making it difficult to accurately predict which patients require early intensive treatment. We argue that consolidative autologous stem cell transplantation in first remission remains the standard of care for the young and fit patient population, based on long-term data from phase II and III trials demonstrating that early transplantation extends both progression-free and overall survival. Novel targeted agents are currently being investigated in both the upfront and relapse settings, but to date there are few data to suggest durable treatment responses that compare favorably with results of transplantation.

Mantle cell lymphoma: 2017 update on diagnosis, risk-stratification, and clinical management

DISEASE OVERVIEW

Mantle cell lymphoma (MCL) is a non-Hodgkin lymphoma characterized by involvement of the lymph nodes, spleen, blood and bone marrow with a short remission duration to standard therapies and a median overall survival (OS) of 4-5 years.

DIAGNOSIS

Diagnosis is based on lymph node, bone marrow, or tissue morphology of centrocytic lymphocytes, small cell type, or blastoid variant cells. A chromosomal translocation t (11:14) is the molecular hallmark of MCL, resulting in the overexpression of cyclin D1. Cyclin D1 is detected by immunohistochemistry in 98% of cases. The absence of SOX-11 or a low Ki-67 may correlate with a more indolent form of MCL. The differential diagnosis of MCL includes small lymphocytic lymphoma, marginal zone lymphoma, and follicular lymphoma.

RISK STRATIFICATION

The MCL International Prognostic Index (MIPI) is the prognostic model most often used and incorporates ECOG performance status, age, leukocyte count, and lactic dehydrogenase. A modification of the MIPI also adds the Ki-67 proliferative index if available. The median OS for the low-risk group was not reached (5-year OS of 60%). The median OS for the intermediate risk group was 51 months and 29 months for the high risk group.

RISK-ADAPTED THERAPY

For selected indolent, low MIPI MCL patients, initial observation may be appropriate therapy. For younger patients with intermediate or high risk MIPI MCL, aggressive therapy with a cytotoxic Regimen followed by autologous stem cell transplantation should be considered. Rituximab maintenance after autologous stem cell transplantation has also improved the progression-free and overall survival. For older symptomatic MCL patients with intermediate or high risk MIPI, combination chemotherapy with R-CHOP, R-Bendamustine, or a clinical trial should be considered. In addition, rituximab maintenance therapy may prolong the progression-free survival. At the time of relapse, agents directed at activated pathways in MCL cells such as bortezomib (NFkB inhibitor), lenalidamide (anti-angiogenesis) and Ibruitinib (Bruton's Tyrosine Kinase [BTK] inhibitor) have demonstrated excellent clinical activity in MCL patients. Autologous or allogeneic stem cell transplantation can also be considered in young patients. Clinical trials with novel agents are always a consideration for MCL patients.

Current and emerging treatment options for mantle cell lymphoma

Mantle cell lymphoma (MCL) is a B-cell non-Hodgkin lymphoma with typically aggressive behavior. The genetic signature is the chromosomal translocation t(11;14)(q13;q32) resulting in overexpression of cyclin D1. Asymptomatic newly diagnosed MCL patients with low tumor burden can be closely observed, deferring therapy to the time of disease progression. Although MCL classically responds to upfront chemotherapy, it remains incurable with standard approaches. For patients in need of frontline therapy, the initial decision is whether to proceed with an intensive treatment strategy or a non-intensive treatment strategy. In general, given the unfavorable risk-benefit profile, older MCL patients should be spared intensive strategies, while younger and fit patients can be considered for intensive strategies. The bendamustine and rituximab (BR) regimen is becoming an increasingly popular treatment option among the elderly population, with improved progression-free survival (PFS) and acceptable side-effect profile. Although rituximab maintenance after R-CHOP improves survival outcomes in elderly patients, no clinical trial to date has shown statistical significance to support the use of rituximab maintenance after BR induction in older patients. In young and fit patients with MCL, an intensive strategy to maximize the length of first remission has emerged as a worldwide standard of care. With current high-dose cytarabine-containing immunochemotherapy regimens followed by autologous stem cell transplantation, the median PFS has exceeded 7 years. In the relapsed or refractory (R/R) setting, reduced intensity conditioning allogeneic hematopoietic stem cell transplantation may offer the highest likelihood of long-term survival in young R/R MCL patients, at the cost of increased risk of non-relapse mortality and chronic graft versus host disease. Novel agents targeting activated pathways in MCL cells, such as bortezomib, lenalidamide, ibrutinib and temsirolimus are now available for the management of R/R disease.

Mantle Cell Lymphoma: Contemporary Diagnostic and Treatment Perspectives in the Age of Personalized Medicine

Mantle cell lymphoma is a clinically heterogeneous disease occurring within a heterogeneous patient population, highlighting a need for personalized therapy to ensure optimal outcomes. It is therefore critical to understand the benefits and risks associated with both intensive and deintensified approaches. In the following review we provide a therapeutic roadmap to strategically guide treatment for newly diagnosed and relapsed/refractory patients highlighting pivotal and recently published results involving known and novel therapies.

Recent advances and future directions in mantle cell lymphoma research: report of the 2016 mantle cell lymphoma consortium workshop

Mantle cell lymphoma (MCL) is an aggressive B-cell non-Hodgkin lymphoma typically associated with the t(11;14) chromosomal translocation, resulting in overexpression of cyclin D1. Although MCL is associated with clinical heterogeneity, outcomes are generally poor and no standard treatment has been established. However, the recent approval of ibrutinib provides a new therapeutic option. Moreover, recent clinical trials have provided new perspectives on the relative efficacy and safety of various approaches for both transplant-eligible and transplant-ineligible patients. Multiple novel strategies are being evaluated in the treatment of MCL, including both targeted agents and cellular immunotherapies. At the Lymphoma Research Foundation's 12th MCL Workshop, researchers gathered to discuss research findings, clinical trial results, and future directions related to MCL, its biology, and its treatment. This manuscript, which includes a summary of each presentation, aims to review recent findings in MCL research and highlight potential areas for future study.

Understanding the New WHO Classification of Lymphoid Malignancies: Why It's Important and How It Will Affect Practice

Improved delineation of lymphoid malignancy biology has prompted refinement of the 2008 World Health Organization (WHO) classification of hematopoietic and lymphoid tumors with a new framework introduced in 2016. This knowledge has provided valuable insights regarding management. Early clonal proliferations have been set apart given their limited potential for malignant dissemination. Increasing knowledge of molecular drivers of aggressive lymphomas has allowed subclassification and opportunity for clinical investigations to personalize therapy. New insights into T-cell pathophysiology has allowed grouping based on shared molecular and cellular features. This article will summarize the key changes in terms of diagnosis and histopathologic definitions, the impact of these changes on clinical management, and the challenges of future research in this field.

Recommendations for Clinical Trial Development in Mantle Cell Lymphoma

Mantle cell lymphoma (MCL) comprises around 6% of all non-Hodgkin's lymphoma (NHL) diagnoses. In younger patients, age less than 60 to 65 years, aggressive induction often followed by consolidation with autologous stem cell transplant has suggested improved outcomes in this population. Less intensive therapies in older patients often followed by maintenance have been studied or are under active investigation. However, despite recent advances, MCL remains incurable, with a median overall survival of around five years. Patients with high-risk disease have particularly poor outcomes. Treatment varies widely across institutions, and to date no randomized trials comparing intensive vs less intensive approaches have been reported. Although recent data have highlighted the heterogeneity of MCL outcomes, patient assessment for treatment selection has largely been driven by patient age with little regard to fitness, disease biology, or disease risk. One critical advance is the finding that minimal residual disease status (MRD) after induction correlates with long-term outcomes. As such, its use as a potential end point could inform clinical trial design. In order to more rapidly improve the outcomes of MCL patients, clinical trials are needed that prospectively stratify patients on the basis of MCL biology and disease risk, incorporate novel agents, and use MRD to guide the need for additional therapy.

Catalog of genetic progression of human cancers: non-Hodgkin lymphoma

The recent application of next-generation sequencing technologies lead to significant improvements in our understanding of genetic underpinnings of non-Hodgkin lymphomas with identification of an unexpectedly high number of novel mutation targets across the different B-cell lymphoma entities. These recently discovered molecular lesions are expected to have a major impact on development of novel biomarkers and targeted therapies as well as patient stratification based on the underlying genetic profile. This review will cover the major discoveries in B-cell lymphomas using next-generation sequencing technologies over the last few years, highlighting alterations associated with relapse and progression of these diseases.

Mantle Cell Lymphoma: A North Indian Tertiary Care Centre Experience

Background: Mantle cell lymphoma (MCL) is an aggressive non-Hodgkin’s lymphoma, with a pathognomonic chromosomal translocation t (11;14). Prognosis is uniformly dismal but there is a paucity of information on MCL from India. Materials and methods: We retrospectively analysed clinicopathological information on all treated patients with MCL at our centre. STATA 14.0 was used for analysis. Survival was assessed by Kaplan-Meier analysis and the Cox’s proportional hazards method. Statistical significance was defined as a P value of < 0.05. Results: Fifty-one patients with MCL were reviewed. The median age at presentation was 57.0 years. Extranodal involvement was seen in 39.0 (74.0%) while bone marrow positivity at presentation was found in 27.0 (54.0%). Initial treatment was chemotherapy with or without rituximab. Patients receiving rituximab-based therapy (n = 24) had 5-year progression-free survival (PFS) of 21.0 (88.0%), compared with 14.0 (61.0%) for those not receiving rituximab (n = 23, P = 0.036). Twenty-three patients were alive with a median follow-up of 20.7 months (range 2.5-89.2). PFS at 1 and 2 years was 51.0% and 27.0%, and overall survival (OS) 78.0% and 72.0%, respectively. Use of more than 2.0 lines of therapy, use of bendamustine-rituximab, and high TLC (>10,000.0/cu.mm) significantly affected PFS. Conclusions: In our experience, MCL patients from north India have an early age at presentation. When treated with regimens including rituximab results in an improved response rate and PFS. This study provided comprehensive insights into the treatment of MCL in a developing country.

Pathogenic role of B-cell receptor signaling and canonical NF-κB activation in mantle cell lymphoma

To interrogate signaling pathways activated in mantle cell lymphoma (MCL) in vivo, we contrasted gene expression profiles of 55 tumor samples isolated from blood and lymph nodes from 43 previously untreated patients with active disease. In addition to lymph nodes, MCL often involves blood, bone marrow, and spleen and is incurable for most patients. Recently, the Bruton tyrosine kinase (BTK) inhibitor ibrutinib demonstrated important clinical activity in MCL. However, the role of specific signaling pathways in the lymphomagenesis of MCL and the biologic basis for ibrutinib sensitivity of these tumors are unknown. Here, we demonstrate activation of B-cell receptor (BCR) and canonical NF-κB signaling specifically in MCL cells in the lymph node. Quantification of BCR signaling strength, reflected in the expression of BCR regulated genes, identified a subset of patients with inferior survival after cytotoxic therapy. Tumor proliferation was highest in the lymph node and correlated with the degree of BCR activation. A subset of leukemic tumors showed active BCR and NF-κB signaling apparently independent of microenvironmental support. In one of these samples, we identified a novel somatic mutation in RELA (E39Q). This sample was resistant to ibrutinib-mediated inhibition of NF-κB and apoptosis. In addition, we identified germ line variants in genes encoding regulators of the BCR and NF-κB pathway previously implicated in lymphomagenesis. In conclusion, BCR signaling, activated in the lymph node microenvironment in vivo, appears to promote tumor proliferation and survival and may explain the sensitivity of this lymphoma to BTK inhibitors.

[Current therapeutic strategies for mantle cell lymphoma]

Mantle cell lymphoma is a subtype of B‑cell lymphoma with a mostly aggressive behavior and poor long-term prognosis. The choice of therapy depends on the age, performance status and risk profile of the patient. Randomized trials have confirmed the superiority of a dose-intensified induction therapy containing cytarabine followed by autologous stem cell transplantation in the first-line treatment of younger patients with a good general condition. Elderly patients benefit from a rituximab maintenance therapy after immunochemotherapy. Novel targeted therapies of the B‑cell receptor pathway with the Bruton's tyrosine kinase inhibitor ibrutinib and the mechanistic target of rapamycin (mTOR) antagonist temsirolimus as well as immunomodulatory drugs (lenalidomide) have shown promising results in relapsed disease. The proteasome inhibitor bortezomib has been approved for first-line treatment in combination with conventional chemotherapy.

Mantle Cell Lymphoma: First-line Therapy in Patients Not Eligible for Stem Cell Transplantation

OPINION STATEMENT

Mantle cell lymphoma is a distinct subtype of non-Hodgkin's lymphoma, which has historically been associated with a poor prognosis. It is now recognized as a heterogeneous disease with variable biologic and clinical behavior. Treatment paradigms have evolved along two lines. Younger, fit mantle cell lymphoma (MCL) patients are generally treated with intensive strategies and older less fit patients with non-intensive strategies. Most of the published literature has focused on intensive strategies, which appear to result in more durable remissions, but with an unclear impact on overall survival. The literature is more sparse for the roughly 50% of patients who are not candidates for intensive strategies, and no "standard" approach has been established for this patient population. However, clues are emerging. Randomized clinical trials have (a) established that bendamustine-rituximab (BR) is more efficacious and less toxic than rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP); (b) established that bortezomib should replace vincristine if using an R-CHOP backbone; and (c) established that maintenance rituximab (MR) is beneficial after an R-CHOP induction. In our opinion, it is reasonable to extrapolate the data supporting MR after R-CHOP and apply MR after a BR induction. In our practice, we recommend BR followed by MR for 2 years to MCL patients not eligible for intensive therapy. An ongoing US intergroup trial is testing the addition of bortezomib to the BR backbone and the addition of lenalidomide to MR. This trial may establish a standard of care in the older MCL population. In addition, exciting options for relapsed MCL have emerged in the last few years, with the introduction of the Bruton tyrosine kinase (BTK) inhibitor ibrutinib and the development of the lenalidomide-rituximab combination. In this article, we will discuss the current available options for these older MCL patients and the evidence supporting those options.

The role of targeted treatment in mantle cell lymphoma: is transplant dead or alive?

Based on the profound biological insights of the last years into the molecular pathogenesis of mantle cell lymphoma and the clinical introduction of new targeted drugs, with high efficacy and a good safety profile, the therapeutic scenario for this tumor has been shown to be thoroughly favourable. No longer characterized by a uniformly dismal prognosis, mantle cell lymphoma has been revealed as a spectrum of different diseases, ranging from very indolent cases to highly aggressive and refractory ones. Thus, there is an urgent need to adapt therapy to accommodate the diverse presentations of the disease. High-dose chemotherapy, followed by autologous stem cell transplantation is the current standard of care for younger patients, generally providing high responses and long survival rates, but hampered by acute and long-term toxicity. In addition, some patients may be overtreated, while others could benefit from targeted approaches, based on the new, molecular-directed compounds. Such a personalized treatment based on the specific characteristics of individual patients may be guided by validated prognostic tools, such as the Mantle Cell Lymphoma International Prognostic Index and the Ki-67 Proliferative Index, as well as by early predictors of treatment response, like minimal residual disease analysis. Moreover, mutation screening of distinctive genomic alterations may provide new, predictive biomarkers, with an additional impact on clinical practice. Only after tailoring treatment according to the clinical and biological heterogeneity of the disease the role of transplantation and modern therapeutic options will be redefined in mantle cell lymphoma.

Idelalisib for the treatment of non-Hodgkin lymphoma

INTRODUCTION

B-cell Non-Hodgkin lymphomas (B-NHLs) include a number of disease subtypes, each defined by the tempo of disease progression and the identity of the cancerous cell. Idelalisib is a potent, selective inhibitor of the delta isoform of phosphatidylinositol-3-kinase (PI3K), a lipid kinase whose over-activity in B-NHL drives disease progression. Idelalisib has demonstrated activity in indolent B-NHL (iB-NHL) and is approved for use as monotherapy in patients with follicular lymphoma and small lymphocytic lymphoma and in combination with rituximab in patients with chronic lymphocytic leukemia.

AREAS COVERED

Herein we review the development and pharmacology of idelalisib, its safety and efficacy in clinical studies of iB-NHL, and its potential for inclusion in future applications in iB-NHL and in combination with other therapies.

EXPERT OPINION

Idelalisib adds to the growing arsenal of iB-NHL pharmacotherapeutics and to the progression of the field toward precision agents with good efficacy and reduced toxicities. Nevertheless, idelalisib carries important risks that require careful patient counseling and monitoring. The appropriate sequencing of idelalisib with other proven treatment options in addition to its potential for combination with established or novel drugs will be borne out in ongoing and planned investigations.

Mantle Cell Lymphoma

Mantle cell lymphoma (MCL) is an uncommon subtype of non-Hodgkin lymphoma previously considered to have a poor prognosis. Large gains were made in the first decade of the new century when clinical trials established the importance of high-dose therapy and autologous stem-cell rescue and high-dose cytarabine in younger patients and the benefits of maintenance rituximab and bendamustine in older patients. In particular, greater depth of understanding of the molecular pathophysiology of MCL has resulted in an explosion of specifically targeted new efficacious agents. In particular, agents recently approved by the Food and Drug Administration include the proteasome inhibitor bortezomib, immunomodulator lenalidomide, and Bruton's tyrosine kinase inhibitor ibrutinib. We review recent advances in the understanding of MCL biology and outline our recommended approach to therapy, including choice of chemoimmunotherapy, the role of stem-cell transplantation, and mechanism-based targeted therapies, on the basis of a synthesis of the data from published clinical trials.

Will new drugs change the standard of care for patients with mantle cell lymphoma?

Mantle Cell lymphoma is a heterogeneous malignancy that has different subtypes with variable levels of aggressiveness. Research on the pathobiology of this disease is helping us understand the etiology for this heterogeneity and has the potential to guide future therapeutic options. The availability of the Ki67 proliferation index and the use of the MIPI score can help determine which of the numerous therapeutic options might be utilized. Minimal Residual Disease testing can act as a guide as to the potential benefit of maintenance therapy. This article discusses the current standard of care for Mantle Cell lymphoma and our current understanding of the pathobiology of the disease leading to strategies to improve patient outcomes with some of the newer targeted agents.

Bortezomib in mantle cell lymphoma: comparative therapeutic outcomes

Mantle cell lymphoma (MCL) is an incurable, typically aggressive subtype of non-Hodgkin lymphoma, accounting for 4%–7% of newly diagnosed non-Hodgkin lymphoma cases. Chemoresistance commonly ensues in MCL, and patients with this heterogeneous disease invariably relapse, underscoring the unmet need for better therapies. Over the past few years, several novel agents with promising activity and unique mechanisms of action have been deemed effective in MCL. Bortezomib is a reversible proteasome inhibitor, approved as a single agent for patients with relapsed/refractory MCL who have received at least one prior line of therapy. Addition of bortezomib to chemoimmunotherapies has demonstrated good tolerability and superior efficacy, both in the upfront and salvage settings, and recently one such combination of bortezomib plus rituximab, cyclophosphamide, doxorubicin, and prednisone was approved as a frontline regimen in untreated patients with MCL. This review examines the role of bortezomib in a multitude of clinical settings and ongoing clinical trials designed to optimize its integration in the current treatment paradigms of MCL.

Lenalidomide plus Rituximab as Initial Treatment for Mantle-Cell Lymphoma

BACKGROUND

Mantle-cell lymphoma is generally incurable. Initial treatment is not standardized but usually includes cytotoxic chemotherapy. Lenalidomide, an immunomodulatory compound, and rituximab, an anti-CD20 antibody, are active in patients with recurrent mantle-cell lymphoma. We evaluated lenalidomide plus rituximab as a first-line therapy.

METHODS

We conducted a single-group, multicenter, phase 2 study with induction and maintenance phases. During the induction phase, lenalidomide was administered at a dose of 20 mg daily on days 1 through 21 of every 28-day cycle for 12 cycles; the dose was escalated to 25 mg daily after the first cycle if no dose-limiting adverse events occurred during the first cycle and was reduced to 15 mg daily during the maintenance phase. Rituximab was administered once weekly for the first 4 weeks and then once every other cycle until disease progression. The primary end point was the overall response rate. Secondary end points included outcomes related to safety, survival, and quality of life.

RESULTS

A total of 38 participants were enrolled at four centers from July 2011 through April 2014. The median age was 65 years. On the basis of the Mantle Cell Lymphoma International Prognostic Index scores, the proportions of participants with low-risk, intermediate-risk, and high-risk disease at baseline were similar (34%, 34%, and 32%, respectively). The most common grade 3 or 4 adverse events were neutropenia (in 50% of the patients), rash (in 29%), thrombocytopenia (in 13%), an inflammatory syndrome ("tumor flare") (in 11%), anemia (in 11%), serum sickness (in 8%), and fatigue (in 8%). At the median follow-up of 30 months (through February 2015), the overall response rate among the participants who could be evaluated was 92% (95% confidence interval [CI], 78 to 98), and the complete response rate was 64% (95% CI, 46 to 79); median progression-free survival had not been reached. The 2-year progression-free survival was estimated to be 85% (95% CI, 67 to 94), and the 2-year overall survival 97% (95% CI, 79 to 99). A response to treatment was associated with improvement in quality of life.

CONCLUSIONS

Combination biologic therapy consisting of lenalidomide plus rituximab was active as initial therapy for mantle-cell lymphoma. (Funded by Celgene and Weill Cornell Medical College; ClinicalTrials.gov number, NCT01472562.).

Mantle cell lymphoma: biology, clinical presentation, and therapeutic approaches

Mantle cell lymphoma is molecularly characterized by the chromosomal translocation t(11;14) (q13;q32) that results in a constitutional overexpression of the cell cycle regulator protein cyclin D1. Generally, the disease is characterized by rapid relapses and poor long-term outcome. However, a subset of patients with indolent disease has been identified. Randomized trials have demonstrated the superiority of dose intensified, cytarabine-containing induction with or without autologous stem cell transplantation in younger patients. In elderly patients, a rituximab-based maintenance has significantly prolonged progression-free and overall survival after treatment with rituximab, cyclophosphamide, doxorubicin hydrochloride, vincristine, and prednisone (R-CHOP). Unfortunately, the vast majority of patients will eventually relapse. Numerous molecular targeting strategies (bortezomib, lenalidomide, temsirolimus, and especially inhibitors of the B-cell receptor pathway) have achieved high response rates in phase II studies and should be strongly considered in relapsed disease.

Treatment options for mantle cell lymphoma

INTRODUCTION

In this article, we provide an accurate overview of both standard treatment option and novel promising therapeutics. Major impact is on novel agents now being tested in randomized clinical trials. While the initial data are promising, they may rapidly expand treatment options, change existing paradigms and further improve outcomes for mantle cell lymphoma (MCL) patients.

AREAS COVERED

MCL is a disease with indolent histology, but aggressive clinical course. However, for now, MCL remains incurable and the search for the most effective and tumor-specific treatment still represents a great challenge for oncohematologists. However, the implementation of chemotherapy together with the anti-CD20 antibody rituximab, as well as the growing use of autologous stem cell transplantation in first remission, have improved effects of treatment in MCL, including even some improvement in overall survival. Recently, treatment modalities for MCL have been expanded by strategies based on several biologically targeted agents, including m-TOR kinase or proteasome inhibitors and immunomodulatory agents, such as lenalidomide. B-cell receptor pathway inhibitors, such as ibrutinib and idelalisib, and histone deacetylase or cyclin-dependent kinase inhibitors have also shown promising activity in resistant or relapsed disease.

EXPERT OPINION

Although enormous progress was made in the treatment of MCL over the last year, the disease remains incurable. One chance for the significant life prolongation is intensive treatment with consolidative auto SCT. However, real progress may be afforded by developing the novel agents described in this article. In this way, MCL may soon become another potentially curable oncological malignancy.

Mantle cell lymphoma: 2015 update on diagnosis, risk-stratification, and clinical management

DISEASE OVERVIEW

Mantle cell lymphoma (MCL) is a non-Hodgkin lymphoma characterized by involvement of the lymph nodes, spleen, blood and bone marrow with a short remission duration to standard therapies and a median overall survival (OS) of 4-5 years.

DIAGNOSIS

Diagnosis is based on lymph node, bone marrow, or tissue morphology of centrocytic lymphocytes, small cell type, or blastoid variant cells. A chromosomal translocation t (11:14) is the molecular hallmark of MCL, resulting in the overexpression of cyclin D1. Cyclin D1 is detected by immunohistochemistry in 98% of cases. The absence of SOX-11 or a low Ki-67 may correlate with a more indolent form of MCL. The differential diagnosis of MCL includes small lymphocytic lymphoma, marginal zone lymphoma, and follicular lymphoma.

RISK STRATIFICATION

The MCL International Prognostic Index (MIPI) is the prognostic model most often used and incorporates ECOG performance status, age, leukocyte count, and lactic dehydrogenase. A modification of the MIPI also adds the Ki-67 proliferative index if available. The median OS for the low-risk group was not reached (5-year OS of 60%). The median OS for the intermediate risk group was 51 months and 29 months for the high risk group.

RISK-ADAPTED THERAPY

For selected indolent, low MIPI MCL patients, initial observation may be appropriate therapy. For younger patients with intermediate or high risk MIPI MCL, aggressive therapy with a cytotoxic regimen ± autologous stem cell transplantation should be considered. For older MCL patients with intermediate or high risk MIPI, combination chemotherapy with R-CHOP, R-Bendamustine, or a clinical trial should be considered. In addition, rituximab maintenance therapy may prolong the progression-free survival. At the time of relapse, agents directed at activated pathways in MCL cells such as bortezomib (NFkB inhibitor), lenalidamide (anti-angiogenesis) and Ibruitinib (Bruton's Tyrosine Kinase [BTK] inhibitor) have demonstrated excellent clinical activity in MCL patients. Autologous or allogeneic stem cell transplantation can also be considered in young patients. Clinical trials with novel agents are always a consideration for MCL patients.

Non-Hodgkin Lymphoma: Diagnosis and Treatment

Non-Hodgkin lymphomas are lymphoid malignant neoplasms with diverse biological and clinical behavior. Patients typically present with persistent painless lymphadenopathy, but some patients may present with constitutional symptoms or with involvement of organs other than the lymphoid and hematopoietic system. An accurate diagnosis, careful staging of the disease, and identification of adverse prognostic factors form the basis of treatment selection. Patients commonly receive chemoimmunotherapy as initial treatment, and radiation therapy may be added if patients have early-stage disease. Most patients respond well to treatment, but relapses are frequent and additional therapies including stem cell transplant are often needed. Because many subtypes of lymphoma remain incurable with current management strategies, clinical trials are in progress to identify novel therapies with promising activity in this disease.

High-dose cytarabine does not overcome the adverse prognostic value of CDKN2A and TP53 deletions in mantle cell lymphoma

CDKN2A and TP53 deletions remain of bad prognostic value in younger MCL patients treated according to the current standard of care. CDKN2A and TP53 deletions have independent deleterious effects and should be considered for treatment decisions in addition to MIPI and Ki-67 index.

New paradigms in mantle cell lymphoma: is it time to risk-stratify treatment based on the proliferative signature?

The elucidation of crucial biologic pathways of cell survival and proliferation has led to the development of highly effective drugs, some of which have markedly improved mantle cell lymphoma (MCL) therapeutic opportunities in the past 10 years. Moreover, an undeniable clinical heterogeneity in treatment response and disease behavior has become apparent in this neoplasm. Thus, the need for biologic markers stratifying patients with MCL in risk classes deserving different treatment approaches has recently been fervently expressed. Among several newly discovered biomarkers, the dismal predictive value of a high proliferative signature has been broadly recognized in large studies of patients with MCL. Different techniques have been used to assess tumor cell proliferation, including mitotic index, immunostaining with Ki-67 antibody, and gene expression profiling. Ki-67 proliferative index, in particular, has been extensively investigated, and its negative impact on relapse incidence and overall survival has been validated in large prospective clinical trials. However, one important pitfall limiting its widespread use in clinical practice is the reported interobserver variability, due to the previous lack of a standardized approach for quantification among different laboratories. In the present review, we describe some of the major techniques to assess cell proliferation in MCL, focusing in particular on the Ki-67 index and its need for a standardized approach to be used in multicenter clinical trials. The value of MCL biologic prognostic scores (as MIPI-b) is discussed, along with our proposal on how to integrate these scores in the planning of future trials investigating a tailored therapeutic approach for patients with MCL. See all articles in this CCR Focus section, "Paradigm Shifts in Lymphoma."

Evaluation of a 'Watch and Wait' Approach for Chemotherapy in Patients with Newly Diagnosed Advanced Non-small Cell Lung Cancer from a Diverse Community Population

AIMS

Systemic therapy in advanced non-small cell lung cancer (NSCLC) is the standard of care. The time of treatment administration has not been examined in the metastatic setting. A 'watch and wait' approach for the initiation of chemotherapy is sometimes used in clinical practice, either because of patient preference, presumed indolent disease behaviour, upfront radiotherapy or other interventions. We propose to evaluate the effect of a watch and wait approach on systemic treatment deliverability and patients' outcomes in a population-based study.

MATERIALS AND METHODS

A retrospective analysis of stage IIIB/IV NSCLC patients referred to medical oncology at the British Columbia Cancer Agency in 2009 was conducted. We defined the following: immediate chemotherapy (ICT) - chemotherapy ≤ 8 weeks from medical oncology consult; watch and wait chemotherapy (WWC) - initial observation with chemotherapy > 8 weeks from medical oncology consultation; watch and wait missed (WWM) - watch and wait patients who did not receive chemotherapy; best supportive care (BSC) - patients deemed chemotherapy ineligible. Statistical methods included Kaplan-Meier analysis, Log-rank tests and Cox proportional hazards modelling.

RESULTS

In total, 744 patients were seen by medical oncology; 355 (48%) received ICT, 173 (23%) watch and wait and 216 (29%) BSC. Of the 173 patients on a watch and wait approach, 42% missed an opportunity for chemotherapy due to poor performance status (50%), death (49%) and comorbidity (1%). The median overall survival was as follows: watch and wait 11.5 months, ICT 12.8 months and BSC 4.3 months (P < 0.0001). Controlling for confounding factors (age, gender, performance status), overall survival was longer in WWC (hazard ratio 0.73, confidence interval 0.81-1.07, P = 0.023) and lower in WWM (hazard ratio 1.68, 95% confidence interval 1.27-2.22, P < 0.0001), compared with ICT.

CONCLUSIONS

A significant proportion of watch and wait patients never receive systemic therapy, predominantly due to a decline in performance status. Patients in the ICT group were younger, had a better performance status and had non-squamous histology compared with the watch and wait group. The overall survival was longer in the patients who received ICT versus watch and wait. The watch and wait strategy is associated with a high risk of missing the opportunity for any chemotherapy and should be judiciously implemented only in carefully selected patients.

Treatment strategies in mantle cell lymphoma

Mantle cell lymphoma (MCL) is a distinct B-cell non-Hodgkin's lymphoma (NHL) defined by the translocation t(11;14). MCL combines characteristics of both indolent and aggressive lymphomas, and it is incurable with conventional chemoimmunotherapy but has a more aggressive disease course. Minimal data exist on treatment of patients diagnosed with early-stage disease (stage I-II non-bulky), as this represents only a small portion of the patients diagnosed with MCL, but therapeutic options evaluated in retrospective studies include radiation or combination radiation and chemotherapy. There is a subset of patients with newly diagnosed MCL that can be observed without treatment, but the majority of patients will require treatment at diagnosis. Treatment is often based on age (≤65-70 years of age), comorbidities, and risk factors for disease. The majority of patients who are younger and without significant comorbidities are treated with intensive induction using combination chemoimmunotherapy regimens, many which include consolidation with autologous stem cell transplant (ASCT). Several regimens have been studied that show improved median progression-free survival (PFS) to 3-6 years in this population of patients. The majority of older patients (≥65-70 years of age) are treated with combination chemoimmunotherapy regimens with consideration of rituximab maintenance, with enrollment on a clinical trial encouraged. Therapy for relapsed disease is dependent on prior treatment, age, comorbidities, and toxicities but includes targeted therapies such as the Bruton's tyrosine kinase (BTK) inhibitor ibrutinib, the immunomodulatory agent lenalidomide, the proteasome inhibitor bortezomib, combination chemoimmunotherapy, ASCT, and allogeneic stem cell transplant in selected cases. Several novel agents and targeted therapies alone or in combination are currently being studied and developed in both the upfront and relapsed setting.