Phase II study of rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone immunochemotherapy followed by yttrium-90-ibritumomab tiuxetan in untreated mantle-cell lymphoma: Eastern Cooperative Oncology Group Study E1499

Radiotheranostics in oncology: current challenges and emerging opportunities

Structural imaging remains an essential component of diagnosis, staging and response assessment in patients with cancer; however, as clinicians increasingly seek to noninvasively investigate tumour phenotypes and evaluate functional and molecular responses to therapy, theranostics - the combination of diagnostic imaging with targeted therapy - is becoming more widely implemented. The field of radiotheranostics, which is the focus of this Review, combines molecular imaging (primarily PET and SPECT) with targeted radionuclide therapy, which involves the use of small molecules, peptides and/or antibodies as carriers for therapeutic radionuclides, typically those emitting α-, β- or auger-radiation. The exponential, global expansion of radiotheranostics in oncology stems from its potential to target and eliminate tumour cells with minimal adverse effects, owing to a mechanism of action that differs distinctly from that of most other systemic therapies. Currently, an enormous opportunity exists to expand the number of patients who can benefit from this technology, to address the urgent needs of many thousands of patients across the world. In this Review, we describe the clinical experience with established radiotheranostics as well as novel areas of research and various barriers to progress.

Radioimmunotherapy in Oncology: Overview of the Last Decade Clinical Trials

Simple Summary

Monoclonal antibody-bearing radionuclides have been under clinical investigation over the last two decades for their use in theranostic (diagnostic and therapeutic) applications in cancer. However, despite the numerous trials that have been conducted, only two radioimmunotherapies (RIT) have been approved by the FDA for the targeted therapy of hematologic tumors expressing CD20 antigens. Moreover, RIT applications for solid cancers faced major issues—such as radiotoxicity due to low antibodies penetrance requiring substantial curative dose—where new discoveries concerning antibody engineering or radionuclides are trying to overcome. Here, we performed an overview of the last 11-year clinical trials involving RIT for solid and non-solid cancers conducted either with full antibodies or antibody fragments. We discussed the low-to-moderate efficiency of RIT compared to conventional therapies and described the last advances in clinic for antibodies carriers (F(ab′)₂, Fab′, ScFv). Finally, we discussed about the complexity of RIT as a therapy and depicted both the issues and the prospects of such a strategy.

Abstract

The specific irradiation of tumors with selective radiolabeled antibodies constitutes an attractive therapeutic approach. Consequent preclinical research has been conducted by both biologists to identify pertinent targets and to select corresponding antibodies (mAb) and by radiochemists to radiolabel mAbs. These numerous preclinical investigations have ascertained the therapeutic interest of radioimmunotherapy (RIT) protocols in mice models. Here, we summarize the clinical studies that have been performed the last decade, including clinical trials (phases I, II, and III), prospective and retrospective studies, and cases series. We thereby reported 92 clinical studies. Among them, 62 concern the treatment of hematological malignancies, and 30 concern solid tumors. For hematologic diseases, the analysis was complex due to the high discrepancy of therapeutic strategies (first-line therapy, consolidation, stem cell transplantation conditioning) as well as the high variety of malignancies that were treated. The clinical studies from the last decade failed to expand anti-CD20 RIT indications but confirmed that RIT using radiolabeled anti-CD20 remains a pertinent choice for patients with relapse follicular lymphomas. For solid tumors, the positive benefit of RIT is more mitigated, apart for few malignancies that can be treated locally. Clinical trials also demonstrated the potential of some antibody formats, such as F(ab′)₂, which has already been approved by the China State FDA under the trend name Licartin®. Despite disparate results, mAb fragments are an interesting prospect for the improvement of RIT efficiency as well as for pretargeted strategies that delay the injection of radioactive treatments from the mAb ones.

Adverse events of radioimmunotherapy for non-Hodgkin lymphoma: A systematic review and meta-analysis

Non-Hodgkin's lymphoma continues to be a highly prevalent entity in the general population. Currently, there are multiple treatment schemes based on chemotherapeutic agents with a great success rate. However, there is a non-negligible percentage of patients who may relapse or be refractory. In this sense, new therapeutic options have emerged in the search for adequate responses, such as monoclonal antibodies that target the CD20 molecule. Another valid option is radioimmunotherapy (RIT), which combines using monoclonal antibodies for the specific targeting of malignant cells and radiation to destroy these cells. Despite the promising results that favor RIT in several clinical studies in different target populations and types of NHL, one situation to consider is the association of this therapy and second neoplasms (acute myeloid leukemia (AML) or myelodysplastic syndrome (MSD)). In this sense, we have proposed this meta-analysis to analyze the published information and determine the incidence of this association and determine this therapy's safety.

Clinical efficacy and safety of first-line treatments in patients with mantle cell lymphoma: A systematic literature review

Mantle cell lymphoma (MCL) is a rare form of non-Hodgkin's lymphoma (NHL) with a median overall survival (OS) of approximately 3-5 years. Systematic literature reviews (SLRs) identified efficacy and safety data for first-line therapies, reported in randomised controlled trials (RCTs) and non-randomised interventional studies (NRISs). Nine and 20 independent studies were included in the RCT and NRISs SLRs, respectively. Differences in the regimens and patient outcomes varied according to patient age and suitability for autologous stem cell transplantation (ASCT). In elderly patients ineligible for transplant, OS ranged from 40 months to 69.6 months. In young transplant-eligible patients, OS ranged from 53 months to 152.4 months. Despite the paucity of directly comparable evidence on the efficacy and safety of MCL therapies, these SLRs highlight that MCL remains a difficult NHL subtype to treat, with short survival highlighting the unmet need for newer treatments that improve patient outcomes.

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.

Treatment of mantle cell lymphoma in Asia: a consensus paper from the Asian Lymphoma Study Group

BACKGROUND

Mantle cell lymphoma (MCL) is a B cell malignancy that can be aggressive and with a poor prognosis; the clinical course is heterogeneous. The epidemiology of MCL in Asia is not well documented but appears to comprise 2-6% of all lymphoma cases based on available data, with variation observed between countries. Although international guidelines are available for the treatment of MCL, there is a lack of published data or guidance on the clinical characteristics and management of MCL in patient populations from Asia. This paper aims to review the available treatment and, where clinical gaps exist, provide expert consensus from the Asian Lymphoma Study Group (ALSG) on appropriate MCL management in Asia. BODY: Management strategies for MCL are patient- and disease stage-specific and aim to achieve balance between efficacy outcomes and toxicity. For asymptomatic patients with clearly indolent disease, observation may be an appropriate strategy. For stage I/II disease, following international guidelines is appropriate, which include either a short course of conventional chemotherapy followed by consolidated radiotherapy, less aggressive chemotherapy regimens, or a combination of these approaches. For advanced disease, the approach is based on the age and fitness of the patient. For young, fit patients, the current practice for induction therapy differs across Asia, with cytarabine having an important role in this setting. Hematopoietic stem cell transplantation (HSCT) may be justified in selected patients because of the high relapse risk. In elderly patients, specific chemoimmunotherapy regimens available in each country/region are a treatment option. For maintenance therapy after first-line treatment, the choice of approach should be individualized, with cost being an important consideration within Asia. For relapsed/refractory disease, ibrutinib should be considered as well as other follow-on compounds, if available.

CONCLUSION

Asian patient-specific data for the treatment of MCL are lacking, and the availability of treatment options differs between country/region within Asia. Therefore, there is no clear one-size-fits-all approach and further investigation on the most appropriate sequence of treatment that should be considered for this heterogeneous disease.

Radioimmunotherapy for mantle cell lymphoma: 5-year follow-up of 90 patients from the international RIT registry

To assess the efficacy of radioimmunotherapy (RIT) with ⁹⁰yttrium-ibrutinib-tiuxetan (90Y-IT) in mantle cell lymphoma, data from 90 patients registered in the RIT Network with a median follow-up (FU) of 5.5 years after RIT were evaluated. 90Y-IT was given as first-line therapy in 45 (50%) and for relapse in 45 (50%) patients. Most patients received 90Y-IT as consolidation after chemoimmunotherapy in first line (98%) and in relapse (53%). As a first-line treatment, 30 patients (pts.) (67%) achieved CR, 10 pts. (22%) PR%. and 1 pt. (2%) PD, and for 4 pts. (9%), no response data was available. At relapse, CR was achieved in 17 pts. (38%), PR in 6 pts. (13%), SD in 2 pts. (4%), and 6 pts. (13%) had PD, while the response was not documented for 14 pts. (31%). After a median FU of 5.5 years, median PFS for all patients was 2.11 (95% CI, 1.03–2.32) years, and median OS was 4.05 (95% CI, 2.79–7.21) years. Eleven pts. (12.2%) developed second malignancy. In conclusion, this is the largest report of MCL pts. treated with 90Y-IT to date. 90Y-IT was most often used as consolidation after first- and second-line chemotherapy and may improve the results achieved using chemoimmunotherapy alone. However, the results are less encouraging compared to treatment with small molecules such as ibrutinib.

Consolidation with 90Y ibritumomab tiuxetan radioimmunotherapy in mantle cell lymphoma patients ineligible for high dose therapy: results of the phase II multicentre Polish Lymphoma Research Group trial, after 8-year long follow-up

Polish Lymphoma Research Group performed a phase-II trial to test whether ⁹⁰Y ibritumomab tiuxetan radioimmunotherapy (Y90) may constitute an alternative consolidation for mantle cell lymphoma patients unfit for high-dose therapy. Forty-six patients were consolidated with Y90 following response to the 1st (n = 34) or 2nd line (n = 12) (immuno)chemotherapy. Majority of the patients had advanced disease (stage IV and presence of B-symptoms in 85% and 70%, respectively) and high MIPI (5.8, range 4-7). Consolidation with Y90 increased the complete remission (CR) rate obtained by the 1st line therapy from 41% to 91% and allowed for median PFS of 3.3 and OS of 6.5 years. In the first relapse, CR rate increased from 16% to 75%, while median PFS and OS totaled 2.2 and 6.5 years, respectively. At 8 years, 30% of patients, consolidated in the 1st line CR were alive, without relapse. Toxicity associated with Y90 is manageable, more severe after fludarabine-based regimens.

Frontline Treatment for Older Patients with Mantle Cell Lymphoma

The natural history of mantle cell lymphoma (MCL) undergoing chemotherapy is a cyclical pattern of remission followed by recurrence of disease due to acquired chemotherapy resistance. The median age of the occurrence of MCL is 65 years, so half of the newly diagnosed MCL patients are considered "elderly." The tolerance to long-term chemotherapy in elderly patients is decreased; hence, the response to frontline therapy used is of paramount importance. We hope that our review may guide clinicians in treating such populations in a more personalized and evidence-based manner.In the older patients with risk variables, frontline treatment is determined according to different body status of fit, unfit or compromised, and frail. In the fit patients, the pursuit of remission and prolongation of survival might currently justify the use of more intense and toxic therapies. For unfit or compromised older patients, disease control needs to be prioritized, maintaining a balance between the benefits and toxicities of the treatment. For frail patients, tolerance of treatment and minimizing myelotoxicity should be the primary focus. "Chemotherapy-free" regimens are likely to be considered as the first-line strategy for this population. On the other hand, in the older MCL population without risk variables, observation or "watch and wait" can prevent overtreatment. Furthermore, more clinical trials and research studies on novel agents and targeted therapies need to be translated into the general population to provide optimal treatment and to guide personalized treatment. IMPLICATIONS FOR PRACTICE: This review emphasizes the importance of frontline therapies for older MCL patients. MCL patients commonly experience a cyclical pattern of remission followed by recurrence of disease due to acquired chemotherapy resistance. As a special population, elderly patients have various comorbidities and decreased organ function, which may reduce the chances of undergoing treatment for recurrent disease. Thus, this older population of patients with MCL should be treated separately and exceptionally. So far, systematic reviews with regard to frontline treatment for older patients with MCL have not been encountered, but the hope is that this review may guide clinicians in treating such populations in a more personalized and evidence-based manner.

Paramount therapy for young and fit patients with mantle cell lymphoma: strategies for front-line therapy

The natural history of mantle cell lymphoma (MCL) is a continuous process with the vicious cycle of remission and recurrence. Because MCL cells are most vulnerable before their exposure to therapeutic agents, front-line therapy could eliminate MCL cells at the first strike, reduce the chance for secondary resistance, and cause long-term remissions. If optimized, it could become an alternative to cure MCL. The key is the intensity of front-line therapy. Both the Nordic 2 and the MD Anderson Cancer Center HCVAD trials, with follow-up times greater than 10 years, achieved long-term survivals exceeding 10 years. But the Achilles heel in both trials were the severe toxicities, such as secondary malignancies including myelodysplastic syndromes /leukemia. Therefore, intensive therapies can act as a double-edged sword providing long term survival at the cost of severe toxicities. In our opinion, although intensive chemotherapy can cause detrimental side effects, it is indispensable given that we run the risk of sacrificing long-term survivals in these young and fit patients. We must seek for a powerful alternative at the front-line. Furthermore, minimal residual disease negativity should be the optimal therapeutic goal to achieve before and after autologous stem cell transplantation. Some novel therapeutic strategies have shown to improve outcomes, but it is not yet clear as to how these results translate in population. Of note, MCL patients need to be stratified at diagnosis and be provided with different intensities of front-line regimen. In this review, we discuss current strategies for the treatment of young patients with newly diagnosed MCL.

Mantle cell lymphoma in the era of precision medicine-diagnosis, biomarkers and therapeutic agents

Despite advances in the development of clinical agents for treating Mantle Cell Lymphoma (MCL), treatment of MCL remains a challenge due to complexity and frequent relapse associated with MCL. The incorporation of conventional and novel diagnostic approaches such as genomic sequencing have helped improve understanding of the pathogenesis of MCL, and have led to development of specific agents targeting signaling pathways that have recently been shown to be involved in MCL. In this review, we first provide a general overview of MCL and then discuss about the role of biomarkers in the pathogenesis, diagnosis, prognosis, and treatment for MCL. We attempt to discuss major biomarkers for MCL and highlight published and ongoing clinical trials in an effort to evaluate the dominant signaling pathways as drugable targets for treating MCL so as to determine the potential combination of drugs for both untreated and relapse/refractory cases. Our analysis indicates that incorporation of biomarkers is crucial for patient stratification and improve diagnosis and predictability of disease outcome thus help us in designing future precision therapies. The evidence indicates that a combination of conventional chemotherapeutic agents and novel drugs designed to target specific dysregulated signaling pathways can provide the effective therapeutic options for both untreated and relapse/refractory MCL.

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.

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.

Mantle Cell Lymphoma: Is It Time for a New Treatment Paradigm?

Mantle cell lymphoma is a relatively rare subtype of lymphoma with a great deal of heterogeneity, both clinically and biologically. Since its recognition as a separate entity in the early 1990s though, consistent efforts have led to a significant improvement of overall survival, from a median overall survival of 2.5 years initially to 5-7 years currently. This decades-long and stepwise progress, summarized in the article, definitely accelerated recently, shedding light on a changing paradigm.

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.

Consolidation anti-CD22 fractionated radioimmunotherapy with 90Y-epratuzumab tetraxetan following R-CHOP in elderly patients with diffuse large B-cell lymphoma: a prospective, single group, phase 2 trial

BACKGROUND

Radioimmunotherapy represents a potential option as consolidation after chemoimmunotherapy in patients with diffuse large B-cell lymphoma who are not candidates for transplantation. We aimed to assess activity and toxicity of fractionated radioimmunotherapy using anti-CD22 ⁹⁰Y-epratuzumab tetraxetan as consolidation after front-line induction chemoimmunotherapy in untreated elderly patients with diffuse large B-cell lymphoma.

METHODS

We did a prospective, single-group, phase 2 trial at 28 hospitals in France, with patients recruited from 17 hospitals. Eligible patients were aged 60-80 years with bulky stage 2-3 or stage 3-4 CD20-positive diffuse large B-cell lymphoma, previously untreated, and not eligible for transplantation. Patients received six cycles of R-CHOP (rituximab [375 mg/m²], cyclophosphamide [750 mg/m²], doxorubicin [50 mg/m²], and vincristine [1·4 mg/m², up to 2 mg] all on day 1, and prednisone [40 mg/m²] daily for 5 days), administered every 14 days. 6-8 weeks after R-CHOP, responders received two doses of 15 mCi/m² (555 MBq/m²) ⁹⁰Y-epratuzumab tetraxetan administered 1 week apart. The primary endpoint was 2 year event-free survival in all registered eligible patients who received at least 1 day of study treatment; the safety analysis was done in the same population. This trial is registered with ClinicalTrials.gov, number NCT00906841.

FINDINGS

Between Oct 22, 2008, and Dec 16, 2010, we recruited 75 patients, of whom four (5%) were excluded after central pathology review; hence, 71 (95%) patients were included in the analysis. All patients started induction treatment; 57 (80%) received radioimmunotherapy. With a median follow-up of 37 months (IQR 30-44), the estimated 2 year event-free survival was 75% (95% CI 63-84). Radioimmunotherapy toxicity consisted of grade 3-4 thrombocytopenia in 48 (84%) of 57 patients and neutropenia in 45 (79%) of 57 patients. One patient developed myelodysplastic syndrome 28 months after receiving radioimmunotherapy and one patient developed acute myeloid leukaemia 5 months after receiving radioimmunotherapy.

INTERPRETATION

Fractionated radioimmunotherapy with ⁹⁰Y-epratuzumab tetraxetan might be appropriate for response consolidation after induction chemotherapy in older patients with advanced diffuse large B-cell lymphoma, but further comparative studies are needed.

FUNDING

Immunomedics, Amgen, Canceropôle Grand Ouest, the GOELAMS/LYSA group and the French National Agency for Research (Investissements d'Avenir).

Short-course R-CHOP followed by (90)Y-Ibritumomab tiuxetan in previously untreated high-risk elderly diffuse large B-cell lymphoma patients: 7-year long-term results

An update at 7 years was conceived for our multicenter phase II study in which 55 elderly high-risk untreated diffuse large B-cell lymphoma patients were treated with ⁹⁰Y-ibritumomab tiuxetan after a short course of rituximab, cyclophosphamide, doxorubicin, vincristine and prednisolone (R-CHOP) as long-term follow-up analyses of this combined therapeutic modality are lacking. The overall response rate to the entire regimen was 80%, including 73% (40/55) of complete response (CR) rate and 7% (4/55) of partial response rate. At the time of writing, 24/55 (43.6%) patients experienced a progression disease and 20 of 40 (50%) patients who obtained a CR are still alive in continuous CR. With a median follow-up of 7 years, the disease-free survival was 43.3% and the progression-free survival was 36.1%. The overall survival at 7.9 years was 38.9% (27 deaths mainly because of lymphoma). Two patients developed secondary hematological malignancies, an acute myeloid leukemia and a myelodysplastic syndrome, at 4 and 3 years from radioimmunotherapy, respectively. Our data confirm the feasibility, efficacy and safety of four cycles of R-CHOP followed by radioimmunotherapy consolidation even in the long term: this combination allows dispensing less chemotherapy in a frail group of patients without invalidating response quality and duration.

90 Y-ibritumomab tiuxetan: a nearly forgotten opportunityr

Y-ibritumomab tiuxetan (90Y-IT) combines the benefits of a monoclonal antibody with the efficacy of radiation in the treatment of B-cell non-Hodgkin lymphoma (NHL), a remarkably radiosensitive hematologic malignancy. 90Y-IT activity has been well established in the indolent setting, being approved in front-line treatment of follicular lymphoma (FL) patients as well as salvage therapy. However, no advantage in OS was observed with respect to standard treatment. Promising data are available also for aggressive B-cell lymphoma. In particular, the addition of RIT to short-course first line chemotherapy enables reduction of chemotherapy while maintaining cure rates in elderly, untreated diffuse large B-cell lymphoma (DLBCL) patients. Furthermore, 90Y-IT improves response rate and outcomes of relapsed/refractory DLBCL patients, eligible and ineligible for autologous stem cell transplantation (ASCT). Clinical results have shown a role of 90Y-IT even in mantle cell lymphoma (MCL). RIT might improve responses and treat minimal residual disease when used as consolidation after first-line chemotherapy in MCL. Moreover, 90Y-IT has demonstrated its efficacy in combination with high-dose chemotherapies as conditioning regimen for ASCT, with evidence suggesting the ability to overcome chemotherapy resistance. Herein, we review the available evidence for this approved drug and examine the recently published and ongoing trials for potential novel indication in aggressive B-cell NHL.

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.

Advancing radioimmunotherapy and its future role in non-Hodgkin lymphoma

Radioimmunotherapy is an effective treatment modality with an acceptable toxicity profile in both indolent B-cell non-Hodgkin lymphoma and histologic transformation. Its ease of administration from a patient's perspective sets it apart from chemoimmunotherapy regimens. It has demonstrated efficacy in a range of different treatment scenarios. Despite its promise as a treatment modality, radioimmunotherapy has been seldom used, and one of the previously available agents is now off the market. Radioimmunotherapy has shown impressive activity in both the relapsed and upfront settings in follicular lymphoma, histologic transformation, as consolidation after chemotherapy, and in conjunction with high-dose chemotherapy and autologous stem cell support. Future efforts should focus on its optimal employment in the upfront setting for follicular lymphoma as well as further investigation of the promising activity in histologic transformation.

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.

90Y-Ibritumomab-Tiuxetan Consolidation Therapy for Advanced-Stage Mantle Cell Lymphoma After First-Line Autologous Stem Cell Transplantation: Is It Time for a Step Forward?

BACKGROUND

Mantle cell lymphoma (MCL) is an aggressive lymphoma with a dismal prognosis because of numerous relapses. Because the most promising results have been obtained with immunochemotherapy followed by autologous cell stem transplantation (ASCT), we evaluated the efficacy of yttrium-90 ibritumomab ((90)Y-IT) consolidation after such an intensive treatment.

PATIENTS AND METHODS

We retrospectively assessed 57 patients affected by intermediate or high-risk MCL in complete remission (CR) or partial remission (PR) after 3 cycles of R-CHOP (rituximab, cyclophosphamide, doxorubicin [hydroxydaunorubicin], vincristine [Oncovin], prednisolone) plus 3 cycles of R-DHAP (dexamethasone, cytarabine [Ara-C], cisplatin [platinum]) followed by ASCT and additional consolidation treatment with (90)Y-IT in 28 cases. All patients underwent 2 years of rituximab maintenance.

RESULTS

After ASCT, 94% achieved CR and 4% achieved PR. The median follow-up was 6.2 years (range, 1.8-9.7 years). Treatment intensification was well tolerated and led to a significantly longer response duration in comparison to standard treatment. In contrast to the historical cohort, the addition of (90)Y-IT seems to overcome important risk factors such as Mantle Cell Lymphoma International Prognostic Index (MIPI) score and bone marrow infiltration.

CONCLUSION

In the present retrospective analysis, immunochemotherapy followed by ASCT resulted in a very high response rate, and subsequent (90)Y-IT consolidation significantly reduced the number of relapses and increased survival, suggesting that (90)Y-IT consolidation might be a valid option in first-line treatment. However, a prospective confirmatory trial is warranted.

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.

High-dose CD20-targeted radioimmunotherapy-based autologous transplantation improves outcomes for persistent mantle cell lymphoma

Autologous stem cell transplant (ASCT) can improve outcomes for mantle cell lymphoma (MCL) patients, yet relapses are frequent. We hypothesized that high-dose anti-CD20 radioimmunotherapy (RIT)-based conditioning could improve results in this setting. We thus assessed 162 consecutive patients with MCL at our centre undergoing ASCT following high-dose RIT-based (n = 61) or standard (n = 101) conditioning. RIT patients were less likely to be in first remission (48% vs. 72%; P = 0·002), be in complete remission (CR) (26% vs. 61%; P < 0·001) and have chemosensitive disease (84% vs. 96%; P = 0·006). RIT-based conditioning was associated with a reduced risk of treatment failure [hazard ratio (HR) 0·40; P = 0·001] and mortality (HR 0·49; P = 0·01) after adjusting for these imbalances. This difference increased as disease status worsened (from CR to partial remission to stable/progressive disease), with respective HRs of 1·14, 0·53 and 0·04 for mortality, and 0·66, 0·36 and 0·14 for treatment failure. RIT-based conditioning appears to improve outcome following ASCT for MCL patients unable to achieve CR after controlling for imbalances in important risk factors. These data support the further study of RIT and radiation-based strategies in a risk-adapted approach to ASCT for persistent MCL.

Current approaches and advance in mantle cell lymphoma treatment

Mantle cell lymphoma (MCL) is a set of heterogeneous non-Hodgkin lymphoma characterized by involvement of lymph nodes, spleen, bone marrow and blood. Under conventional treatment, survival time is 4 to 5 years with short remission period and there is still no standard treatment for MCL. In general, a close observation period called "watchful waiting" is used in elderly patients with low-risk slow clinical progress. And intensive chemotherapy including high-dose of cytarabine ± autologous hematopoietic stem cell transplantation (auto-HSCT) is recommended for younger and fit patients. Allogenic stem cell transplantation (allo-SCT) and drugs targeting the cell metabolic pathway, such as bortezomib (NF-κB inhibitor) and lenalidomide (anti-angiogenesis drug), are considerable treatments for relapsed/refractory patients. Clinical trials and less intensive chemotherapy such as R-CHOP (rituximab with cyclophosphamide, hydroxydaunomycin, oncovin and prednisone) and R-bendamustine should be considered for elderly MCL patients who are at intermediate/high risk. Recent clinical trials with ibrutinib (Bruton's Tyrosine Kinase inhibitor) and temsirolimus (mTOR inhibitor) have shown excellent efficacies in the treatment of MCL. This review will introduce the present status and major therapeutic progress in the treatment of MCL over recent years in order to provide a cutting edge to look into promising clinical progress of MCL.

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.

Mantle cell lymphoma: evolving management strategies

Mantle cell lymphoma (MCL) is a rare and aggressive form of non-Hodgkin's lymphoma that generally affects older individuals and continues to have one of the worst outcomes of all the lymphomas. Over the last decade, there has been a widespread adoption of cytarabine-based therapy in younger patients, and the incorporation of rituximab into chemotherapeutic regimens has become an evidence-based standard of care. However MCL remains a largely incurable disease, and following relapse, it can be a challenge to manage. Although it is possible to define prognosis reliably, there are, as yet, no clear diagnostic or response-adjusted parameters that can help to guide therapeutic decisions. However, there are a number of highly active targeted therapies that are moving into the clinic that are set to transform the therapeutic paradigm for this disease in the very near future. This review will explore the molecular pathogenesis of MCL and the current and evolving therapeutic strategies for this disease.

Radioimmunoconjugates for the treatment of cancer

Radioimmunotherapy (RIT) has been developed for more than 30 years. Two products targeting the CD20 antigen are approved in the treatment of non-Hodgkin B-cell lymphoma (NHBL): iodine 131-tositumomab and yttrium 90-ibritumomab tiuxetan. RIT can be integrated in clinical practice for the treatment of patients with relapsed or refractory follicular lymphoma (FL) or as consolidation after induction chemotherapy. High-dose treatment, RIT in first-line treatment, fractionated RIT, and use of new humanized monoclonal antibodies (MAbs), in particular targeting CD22, showed promising results in NHBL. In other hemopathies, such as multiple myeloma, efficacy has been demonstrated in preclinical studies. In solid tumors, more resistant to radiation and less accessible to large molecules such as MAbs, clinical efficacy remains limited. However, pretargeting methods have shown clinical efficacy. Finally, new beta emitters such as lutetium 177, with better physical properties will further improve the safety of RIT and alpha emitters, such as bismuth 213 or astatine 211, offer the theoretical possibility to eradicate the last microscopic clusters of tumor cells, in the consolidation setting. Personalized treatments, based on quantitative positron emission tomography (PET), pre-therapeutic imaging, and dosimetry procedures, also could be applied to adapt injected activity to each patient.

Management of mantle cell lymphoma in the elderly: current and potential strategies

Mantle cell lymphoma is a distinct subtype of B-cell non-Hodgkin lymphoma, accounting for 3-10 % of all non-Hodgkin lymphoma cases. The median age at diagnosis is nearly 70 years. The prognosis of patients is based on the Mantle Cell Lymphoma International Prognostic Index, which is calculated on the basis of four independent prognostic factors (age, performance status, serum lactate dehydrogenase and leukocyte count). Treatment of elderly patients with de novo untreated mantle cell lymphoma is based on rituximab combined with chemotherapy. The most commonly used regimen is the classical CHOP21 (cyclophosphamide, doxorubicin, vincristine and prednisone) regimen. Bendamustine is also an option, especially for patients with cardiac comorbidities. In elderly patients who are relatively young and fit, an approach based on treatment usually used for younger patients, with cytarabine-based induction followed by autologous stem cell transplantation, should be discussed. Treatment of relapsing patients is based on the use of newer effective drugs, including bortezomib, lenalidomide and thalidomide, and mammalian target of rapamycin (mTOR) inhibitors, such as temsirolimus. These drugs are often combined with rituximab and can be prescribed in combination with chemotherapy. Promising new drugs are Bruton tyrosine kinase inhibitors and other inhibitors of the phosphoinositide 3-kinase (PI3K)-mTOR-protein kinase B (AKT) pathway. Despite these new advances, mantle cell lymphoma remains an incurable disease, and further basic and clinical research is warranted.

Current regimens and novel agents for mantle cell lymphoma

Mantle cell lymphoma is a heterogeneous subtype of non-Hodgkin lymphoma. Conventional treatment with immunochemotherapy followed by autologous stem cell transplantation or intensive immunochemotherapy alone has improved outcomes, but the disease remains incurable. Recent advances in basic and translational research have significantly enhanced our understanding of disease pathogenesis and have sparked the development of novel therapies. Novel agents include the proteasome inhibitor bortezomib, the immunomodulatory agent lenalidomide, the phosphatidylinositol-4,5-bisphosphate 3-kinase pathway inhibitor idelalisib and the Bruton tyrosine kinase inhibitor ibrutinib. Preliminary results from clinical trials, especially from studies of ibrutinib, have proven these agents to be effective. In ongoing studies, these agents are being integrated into conventional immunochemotherapy regimens to hopefully improve patient outcomes.

Recent advances in the management of mantle cell lymphoma

PURPOSE OF REVIEW

This review will discuss the most recent literature regarding frontline therapy, treatment of patients not eligible for intensive chemotherapy, and novel agents for relapsed/refractory patients with mantle cell lymphoma (MCL).

RECENT FINDINGS

Longer follow-up of previously studied intensive regimens still demonstrates encouraging results, but late relapses are still evident. Consolidation and maintenance strategies continue to be attractive options to be explored in this disease that is characterized by frequent relapses and short remissions. The combination of bendamustine-rituximab was demonstrated to be noninferior and less toxic to R-CHOP and should be considered the new standard of care for elderly patients. Multiple novel agents directed towards different molecular targets like BTK, mTOR, PI3K, HDAC, and BCL-2, involved in the pathogenesis of MCL have shown promising results.

SUMMARY

Management of MCL still represents a challenge due to heterogeneity of the disease. As we approach the molecular era of oncology, future strategies should focus on combination of newer agents with known effective regimens to improve outcome.

Nordic MCL3 study: 90Y-ibritumomab-tiuxetan added to BEAM/C in non-CR patients before transplant in mantle cell lymphoma

The main objective of the MCL3 study was to improve outcome for patients not in complete remission (CR) before transplant by adding (90)Y-ibritumomab-tiuxetan (Zevalin) to the high-dose regimen. One hundred sixty untreated, stage II-IV mantle cell lymphoma patients <66 years received rituximab (R)-maxi-CHOP (cyclophosphamide, hydroxydaunorubicin, vincristine, and prednisone) alternating with R-high-dose cytarabine (6 cycles total), followed by high-dose BEAM/C (bis-chloroethylnitrosourea, etoposide, cytarabine, and melphalan or cyclophosphamide) and autologous stem cell transplantation from 2005 to 2009. Zevalin (0.4 mCi/kg) was given to responders not in CR before transplant. Overall response rate pretransplant was 97%. The outcome did not differ from that of the historic control: the MCL2 trial with similar treatment except for Zevalin. Overall survival (OS), event-free survival (EFS), and progression-free survival (PFS) at 4 years were 78%, 62%, and 71%, respectively. For responding non-CR patients who received Zevalin, duration of response was shorter than for the CR group. Inferior PFS, EFS, and OS were predicted by positron emission tomography (PET) positivity pretransplant and detectable minimal residual disease (MRD) after transplant. In conclusion, positive PET and MRD were strong predictors of outcome. Intensification with Zevalin may be too late to improve the outcome of patients not in CR before transplant. This trial was registered at www.clinicaltrials.gov as #NCT00514475.

Role of ibrutinib for the treatment of mantle cell lymphoma in the elderly

SUMMARY Mantle cell lymphoma (MCL) is an uncommon, incurable B-cell non-Hodgkin lymphoma that primarily occurs in the elderly. There is no standard management of MCL, with options varying from observation in asymptomatic patients to aggressive induction/consolidation regimens in younger patients with rapidly progressive disease. Ibrutinib is a first-in-class covalent inhibitor of Bruton’s tyrosine kinase and has shown clinical activity in several B-cell lymphomas including MCL. It is taken orally once daily and appears to be well tolerated. Based on promising results from a Phase II clinical trial in MCL, ibrutinib received breakthrough therapy designation and was approved by the US FDA for treatment of patients with MCL that have received at least one prior line of therapy. It is undergoing further testing in the front line and relapsed setting.

Current and emerging therapies in mantle cell lymphoma

Mantle Cell Lymphoma, characterized by the t(11;14)(q13; q32) chromosomal translocation and cyclin D1 expression, remains one of the most challenging lymphoma subtypes to treat. Therapy can be divided into treatment modalities for younger, stem cell transplant (SCT)-eligible patients vs older, SCT-ineligible patients. For clinically fit patients younger than 60-65 years of age we recommend cytarabine-containing induction and conditioning regimens such as Rituximab (R)-CHOP alternating with R-DHAP followed by autologous SCT consolidation. Elderly patients benefit from R-bendamustine or R-CHOP with maintenance rituximab following induction therapy, especially after R-CHOP. While standard chemoimmunotherapy provides high overall response rates, the responses are not durable and sequential therapies are thus necessary. MCL is proving to be sensitive to novel therapies that may in the near future become useful adjuncts to standard regimens. For example, bortezomib, lenalidomide, and temsirolimus each have single-agent efficacy in relapsed and refractory disease. Several targeted agents are emerging that likewise may transform management of MCL. The B-cell receptor pathway appears to be critical in the pathogenesis of MCL, and novel agents such as ibrutinib and idelalisib that target this signaling pathway are highly active in relapsed and refractory MCL. Similarly, cell cycle inhibitors targeting cyclin dependent kinases as well as HDAC inhibitors have shown promise in early studies.