Current treatment standards and emerging strategies in mantle cell lymphoma

Type B Lactic Acidosis in a Patient with Mantle Cell Lymphoma

Type B lactic acidosis is an uncommon medical emergency in which acid production overwhelms hepatic clearance. This specific etiology of lactic acidosis occurs without organ hypoperfusion and has been most commonly described in patients with hematologic malignancies but also in patients with solid tumors. The mechanism by which cancer cells switch their glucose metabolism toward increasingly anaerobic glycolytic phenotypes has been described as the "Warburg effect." Without treating the underlying malignancy, the prognosis for patients diagnosed with malignancy-related type B lactic acidosis is extremely poor. Here, we present a case of a 66-year-old male who was diagnosed with type B lactic acidosis secondary to mantle cell lymphoma. Bicarbonate drip was started to correct the lactic acidosis. The patient was also immediately treated with rituximab chemotherapy combined with rasburicase to avoid the hyperuricemia associated with tumor lysis syndrome. He responded to the early treatment and was discharged with normal renal function. Type B lactic acidosis secondary to hematologic malignancy is important to recognize. In order to successfully treat this syndrome, early diagnosis and simultaneous treatment of the imbalance of lactic acid levels and the underlying malignancy are necessary.

Non-chemotherapy Options for Newly Diagnosed Mantle Cell Lymphoma

OPINION STATEMENT

Mantle cell lymphoma is a rare and incurable non-Hodgkin lymphoma with a heterogenous clinical presentation. Typically, treatment consists of frontline chemoimmunotherapy induction with or without autologous stem cell transplant (ASCT) as consolidation. However, this approach has the propensity to increase short- and long-term toxicities, such as secondary malignancies, without being curative. Genomic profiling of MCL will allow for greater impact of new targeted therapies in the future and may become a helpful tool to guide treatment. Based on the data discussed, use of non-chemotherapy options may become the preferred approach for frontline therapy as opposed to conventional chemotherapy and hematopoietic stem cell transplants.

Using the primary site as a prognostic tool for nodal mantle cell lymphoma: a SEER-based study

Background: Nodal mantle cell lymphoma (NMCL) has a worse survival than extra-nodal mantle cell lymphoma. Materials & methods: A cohort study was conducted to evaluate the primary site role as a mortality predictor using data from 1983 to 2011 from the Surveillance, Epidemiology, and End Results (SEER) database. Results: Most patients had NMCL in multiple regions (71.9%). There was a significantly increased incidence of NMCL cases over years with 83.2% of them occurred between 1998 and 2011. The mean survival was 52.9 months with overall survival/cancer-specific survival rate of 29.2/42.9%, respectively. Lymph nodes of intrathoracic and multiple regions had a worse overall survival while the head, face and neck, intra-abdominal, pelvic, inguinal region and leg as well as multiple regions had worse cancer-specific survival. Conclusion: NMCL primary site can serve as a prognostic factor. We encourage adding it to MCL International Prognostic Index.

Exosome complex genes mediate RNA degradation and predict survival in mantle cell lymphoma

Exosome complex (EXOSC) genes, which encode a multi-protein intracellular complex, mediate the degradation of various types of RNA molecules. EXOSCs, also known as polymyositis/scleroderma complexes, exist in eukaryotic cells and archaea, and primarily mediate 3′ to 5′mRNA degradation. However, how EXOSC genes are implicated in processes of B-cell immune-associated pathways and B-cell tumorigenesis remains unclear. The present bioinformatics study indicated that 6 of 10 EXOSC genes, particularly the EXO.index, were able to predict the survival of patients with mantle cell lymphoma (MCL), by analyzing gene expression profiles of 123 patients with MCL from the Gene Expression Omnibus database. The results suggested that EXOSC gene expression may be a molecular marker for MCL. Compared with the whole transcript profile, patients with MCL with a high EXO.index exhibited poorer survival and decreased RNA levels, which was also verified in a second dataset. The EXOSC genes may be associated with DNA repair and B-cell activation pathways, which may be the cause of poorer survival of patients with MCL.

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.

Survival benefit of mantle cell lymphoma patients enrolled in clinical trials; a joint study from the LYSA group and French cancer registries

PURPOSE

Mantle cell lymphoma (MCL) is a rare non-Hodgkin's lymphoma entity with a poor prognosis. Therapeutic advances have improved the survival of patients enrolled in clinical trials; however, their impact on patients outside clinical trials remains unclear. In this work, we compared patient outcome inside and outside clinical trials.

METHODS

We identified MCL patients recorded in six French population-based registries between 2008 and 2012 to perform a comparison with patients enrolled in two prospective multicenter MCL clinical trials conducted by the LYSA group during the same period. Variables associated with inclusion in a clinical trial were identified using a logistic regression. Pohar-Perme estimator and Nelson et al. flexible parametric model was used to estimate net survival probabilities and prognosis factors on excess mortality.

RESULTS

A total of 312 registry patients were compared to the 372 patients enrolled in LYSA clinical trials. Patients included in clinical trials were younger (median age 60 vs 74, p < 0.001). Age and Ann Arbor stage IV were independently associated with enrollment [OR = 0.09 (0.06-0.12) and OR = 1.61 (1.11-2.34), respectively]. The 4 year net survival was better in clinical trials [79.9% (75.9-84.7) vs 60.3% (53.6-67.0)]. This result was confirmed in multivariate analysis in patients older than 65 years with a lower excess mortality rate [0.33 (0.17-0.66)].

CONCLUSIONS

MCL included in trials are highly selected patients who are not representative of MCL patients who are encountered in everyday practice. With widened inclusion criteria, clinical trial patients could be more representative of the general population.

Mantle Cell Lymphoma Presenting with Acute Bilateral Ophthalmoplegia

A 72-year-old woman presented with acute onset of double vision, bilateral complete blepharoptosis, and nearly complete ophthalmoplegia. Orbital and brain magnetic resonance imaging were normal. Further investigation revealed bicytopenia with hepatosplenomegaly. Liver biopsy revealed mantle cell lymphoma. Cytology later showed the presence of mantle cells in cerebrospinal fluid analysis. Her ophthalmoplegia improved from her first cycle of systemic and intrathecal chemotherapy. To the best of our knowledge, this is the second case in the literature of mantle cell lymphoma with central nervous system involvement presenting with ophthalmoplegia. This symptom should be considered one of the initial signs of mantle cell lymphoma.

What is the optimal initial management of the older MCL patient?

The current first line treatment of a patient with mantle cell lymphoma (MCL) is often considered as too toxic for elderly patients. The elderly, however, comprise the majority of the patients with MCL. The results of several recent studies have shown that the outcome of this patient group is not as dismal as in the past. Indeed, if patients are not considered frail, and can tolerate rituximab and moderate intensive chemotherapy such as R-CHOP followed by rituximab maintenance or R-bendamustine, a 4-year overall survival of >80% can be achieved. In this chapter the developments of the regimens, resulting in the standard treatment options for these patients, are discussed.

The Role of CD200 and CD43 Expression in Differential Diagnosis between Chronic Lymphocytic Leukemia and Mantle Cell Lymphoma

Objective:

Atypical chronic lymphocytic leukemia (CLL) is most frequently confused with mantle cell lymphoma (MCL). Several markers may contribute to the diagnosis of CLL. However, there is no consensus on which markers are needed to be used in flow cytometry for the diagnosis of CLL. The aim of the present study was to investigate the role of CD43 and CD200 markers in the differential diagnosis between CLL and MCL.

Materials and Methods:

To address this issue, 339 consecutive patients with CLL and MCL were included in the flow cytometry lymphoproliferative disease panel for evaluation of CD43 and CD200 expressions, but not in the Matutes scoring system.

Results:

CD200 was expressed in 97.3% of atypical CLL cases, whereas it was dimly expressed in only 6.1% of MCL cases. CD43 expression was 95.7% in atypical CLL cases. In the MCL cases, its expression rate was 39.4%.

Conclusion:

CD43 and CD200 were found to be more valuable markers than CD22, CD79b, and FMC7. CD43 and CD200 could also be considered as definitive markers in atypical CLL patients, for whom the Matutes scoring system remains ineffective.

Autologous stem cell transplantation (ASCT) in patients with mantle cell lymphoma: a retrospective study of the Spanish lymphoma group (GELTAMO)

Guidelines recommend autologous stem cell transplantation (ASCT) consolidation in first complete or partial response after regimens including rituximab (R) and high-dose AraC (HDAC), but its use beyond that response is questioned. We present a retrospective analysis of 268 patients with MCL who received ASCT. With a median follow-up for survival patients of 54 months, progression-free survival and overall survival for the whole series were 38 and 74 months, respectively, and for patients transplanted in first CR 49 and 97 months, respectively. Patients without CR before transplant were analyzed separately, those who achieved CR after transplantation had better PFS (48 vs 0.03 months, p < 0.001) and OS (92 vs 16 months, p < 0.001) than the remaining. In univariate analysis, first CR at transplant (p = 0.01) and prior rituximab (p = 0.02) were the variables associated with PFS. For OS, the same variables resulted significant (p = 0.03 and p < 0.001, respectively). In multivariate analysis, only the status at transplant (first CR) remained significant. This retrospective study concludes that ASCT consolidation in first CR induces high survival rates. In other stages of disease, the need of ASCT as consolidation may be questioned.

Is myeloablative dose intensity necessary in allogeneic hematopoietic cell transplantation for lymphomas?

The advent of novel immunotherapy and tyrosine kinase inhibitors has ushered a new era in the treatment of Hodgkin and non-Hodgkin lymphomas. Allogeneic hematopoietic cell transplantation remains, however, a vital component in the management and potential cure of lymphomas, especially in the relapsed setting. Considering the biological and clinical heterogeneity of various subtypes of lymphomas, the optimal intensity of conditioning regimens remains controversial. Reduced intensity conditioning regimens have broadened applicability of the procedure to older and frail patients. Observational studies suggest that although reduced intensity allografting is associated with higher risk of relapse, overall survival is comparable and in some cases even better, than observed with myeloablative regimens. Here, we review the available published data pertaining to allogeneic hematopoietic cell transplantation using reduced intensity or myeloablative conditioning for various lymphoma histologies. Owing to the lack of randomized prospective trials, recommendations are mainly based on registry and single-institution studies. Special emphasis must be given to implementing strategies to prevent relapse when using reduced intensity regimens. Identifying particular patients who may benefit from myeloablative regimens in lymphomas remains to be better defined.

The REFRACT-LYMA cohort study: a French observational prospective cohort study of patients with mantle cell lymphoma

BACKGROUND

Mantle Cell Lymphoma (MCL) is often associated with progression, temporary response to therapy and a high relapse rate over time resulting in a poor long-term prognosis. Because MCL is classified as an incurable disease, therapeutic resistance is of great interest. However, knowledge about the biological mechanisms underlying resistance associated with MCL therapies and about associated predictors remains poor. The REFRACT-LYMA Cohort, a multicenter prospective cohort of patients with MCL, is set up to address this limitation. We here describe the study background, design and methods used for this cohort.

METHODS/DESIGN

The REFRACT-LYMA Cohort Study aims at including all patients (>18 years old) who are diagnosed with MCL in any stage of the disease and treated in specialized oncology centers in three public hospitals in Northwestern France. Any such patient providing a signed informed consent is included. All subjects are followed up indefinitely, until refusal to participate in the study, emigration or death. The REFRACT-LYMA follow-up is continuous and collects data on socio-economic status, medical status, MCL therapies and associated events (resistance, side effects). Participants also complete standardized quality of life (QOL) questionnaires. In addition, participants are asked to donate blood samples that will support ex vivo analysis of expression and functional assays required to uncover predictive biomarkers and companion diagnostics. If diagnostic biopsies are performed during the course of the disease, extracted biological samples are kept in a dedicated biobank.

DISCUSSION

To our knowledge, the REFRACT-LYMA Cohort Study is the first prospective cohort of patients with MCL for whom "real-life" medical, epidemiological and QOL data is repeatedly collected together with biological samples during the course of the disease. The integrative cohort at mid-term will be unique at producing a large variety of data that can be used to conceive the most effective personalized therapy for MCL patients. Additionally, the REFRACT-LYMA Cohort puts the medical care of MCL patients in a health and pharmacoeconomic perspective.

Bilateral ocular panadnexal mass as initial presentation of systemic blastoid variant of mantle-cell lymphoma

A 66-year-old man developed a slowly enlarging, bilateral, painless, periorbital, and orbital swelling with ptosis, nonaxial proptosis, chemosis, exposure keratopathy, and decreased vision in both eyes. He had fever, night sweats, and weight loss (B-symptoms), along with lymphadenopathy and elevated serum lactate dehydrogenase, with no prior history of lymphoma. A transpalpebral incisional biopsy revealed a rare case of mantle-cell lymphoma of blastoid variant, stage IVB. The main immunophenotype characteristics were cyclin D1+, CD5+, CD10-, CD23-, Bcl-6-/+, and a high (up to 80%) Ki-67 proliferation index. Following an excellent response to the immune-chemotherapy treatment plan, all ocular adnexal lymphoma manifestations disappeared completely; however, 13 months after the initial presentation, there was a recurrence of the disease with rapid worsening and death. The blastoid variant of mantle cell lymphoma, a rare subtype of mantle-cell lymphoma, is a highly aggressive neoplasm, ultimately having a fatal outcome. As the initial manifestation of the disease, ocular adnexal region blastoid variant of mantle-cell lymphoma is an exceptional event, with only one previous case reported.

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

BACKGROUND

Lenalidomide, an immunomodulatory drug with antineoplastic and antiproliferative effects, showed activity in many single-group studies in relapsed or refractory mantle cell lymphoma. The aim of this randomised study was to examine the efficacy and safety of lenalidomide versus best investigator's choice of single-agent therapy in relapsed or refractory mantle cell lymphoma.

METHODS

The MCL-002 (SPRINT) study was a randomised, phase 2 study of patients with mantle cell lymphoma aged 18 years or older at 67 clinics and academic centres in 12 countries who relapsed one to three times, had Eastern Cooperative Oncology Group performance status of 0-2, at least one measurable lesion to be eligible, and who were ineligible for intensive chemotherpy or stem-cell transplantation. Using a centralised interactive voice response system, we randomly assigned (2:1) patients in a permuted block size of six to receive lenalidomide (25 mg orally on days 1-21 every 28 days) until progressive disease or intolerability, or single-agent investigator's choice of either rituximab, gemcitabine, fludarabine, chlorambucil, or cytarabine. Randomisation was stratified by time from diagnosis, time from last anti-lymphoma therapy, and previous stem-cell transplantation. Individual treatment assignment between lenalidomide and investigator's choice was open label, but investigators had to register their choice of comparator drug before randomly assigning a patient. Patients who progressed on investigator's choice could cross over to lenalidomide treatment. We present the prespecified primary analysis results in the intention-to-treat population for the primary endpoint of progression-free survival, defined as the time from randomisation to progressive disease or death, whichever occurred first. Patient enrolment is complete, although treatment and collection of additional time-to-event data are ongoing. This study is registered with ClinicalTrials.gov, number NCT00875667.

FINDINGS

Between April 30, 2009, and March 7, 2013, we enrolled 254 patients in the intention-to-treat population (170 [67%] were randomly assigned to receive lenalidomide, 84 [33%] to receive investigator's choice monotherapy). Patients had a median age of 68·5 years and received a median of two previous regimens. With a median follow-up of 15·9 months (IQR 7·6-31·7), lenalidomide significantly improved progression-free survival compared with investigator's choice (median 8·7 months [95% CI 5·5-12·1] vs 5·2 months [95% CI 3·7-6·9]) with a hazard ratio of 0·61 (95% CI 0·44-0·84; p=0·004). In the 167 patients in the lenalidomide group and 83 patients in the investigator's choice group who received at least one dose of treatment the most common grade 3-4 adverse events included neutropenia (73 [44%] of 167 vs 28 [34%] of 83) without increased risk of infection, thrombocytopenia (30 [18%] vs 23 [28%]), leucopenia (13 [8%] vs nine [11%]), and anaemia (14 [8%] vs six [7%]).

INTERPRETATION

Patients with relapsed or refractory mantle cell lymphoma ineligible for intensive chemotherapy or stem-cell transplantation have longer progression-free survival, with a manageable safety profile when treated with lenalidomide compared with monotherapy investigator's choice options.

FUNDING

Celgene Corporation.

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.

Long-term follow-up of MCL patients treated with single-agent ibrutinib: updated safety and efficacy results

Ibrutinib, an oral inhibitor of Bruton tyrosine kinase, is approved for patients with mantle cell lymphoma (MCL) who have received one prior therapy. We report the updated safety and efficacy results from the multicenter, open-label phase 2 registration trial of ibrutinib (median 26.7-month follow-up). Patients (N = 111) received oral ibrutinib 560 mg once daily, and those with stable disease or better could enter a long-term extension study. The primary end point was overall response rate (ORR). The median patient age was 68 years (range, 40-84), with a median of 3 prior therapies (range, 1-5). The median treatment duration was 8.3 months; 46% of patients were treated for >12 months, and 22% were treated for ≥2 years. The ORR was 67% (23% complete response), with a median duration of response of 17.5 months. The 24-month progression-free survival and overall survival rates were 31% (95% confidence interval [CI], 22.3-40.4) and 47% (95% CI, 37.1-56.9), respectively. The most common adverse events (AEs) in >30% of patients included diarrhea (54%), fatigue (50%), nausea (33%), and dyspnea (32%). The most frequent grade ≥3 infections included pneumonia (8%), urinary tract infection (4%), and cellulitis (3%). Grade ≥3 bleeding events in ≥2% of patients were hematuria (2%) and subdural hematoma (2%). Common all-grade hematologic AEs were thrombocytopenia (22%), neutropenia (19%), and anemia (18%). The prevalence of infection, diarrhea, and bleeding was highest for the first 6 months of therapy and less thereafter. With longer follow-up, ibrutinib continues to demonstrate durable responses and favorable safety in relapsed/refractory MCL. The trial is registered to www.ClinicalTrials.gov as #NCT01236391.

Zevalin and BEAM (Z-BEAM) versus rituximab and BEAM (R-BEAM) conditioning chemotherapy prior to autologous stem cell transplantation in patients with mantle cell lymphoma

Early relapse is common in patients with mantle cell lymphoma (MCL) highlighting the unmet need for further improvement of therapeutic options for these patients. CD20 inhibition combined with induction chemotherapy as well as consolidation with high-dose chemotherapy (HDCT) is increasingly considered cornerstones within current therapy algorithms of MCL whereas the role of radioimmunotherapy is unclear. This retrospective single center study compared 46 consecutive MCL patients receiving HDCT in first or second remission. Thirty-five patients had rituximab and BEAM (R-BEAM), and 11 patients received ibritumomab tiuxetan (Zevalin®), an Yttrium-90 labeled CD20 targeting antibody, prior to BEAM (Z-BEAM) followed by autologous stem cell transplantation (ASCT). We observed that the 5-year overall survival (OS) in the R-BEAM and Z-BEAM groups was 55% and 71% (p = 0.288), and the 4-year progression free survival (PFS) was 32% and 41%, respectively (p = 0.300). There were no treatment related deaths in both groups, and we observed no differences in toxicities, infection rates or engraftment. Our data suggest that the Z-BEAM conditioning regimen followed by ASCT is well tolerated, but was not associated with significantly improved survival compared to R-BEAM. Copyright © 2015 John Wiley & Sons, Ltd.

Astatine-211 conjugated to an anti-CD20 monoclonal antibody eradicates disseminated B-cell lymphoma in a mouse model

α-Emitting radionuclides deposit a large amount of energy within a few cell diameters and may be particularly effective for radioimmunotherapy targeting minimal residual disease (MRD). To evaluate this hypothesis, (211)At-labeled 1F5 monoclonal antibody (mAb) (anti-CD20) was studied in both bulky lymphoma tumor xenograft and MRD animal models. Superior treatment responses to (211)At-labeled 1F5 mAb were evident in the MRD setting. Lymphoma xenograft tumor-bearing animals treated with doses of up to 48 µCi of (211)At-labeled anti-CD20 mAb ([(211)At]1F5-B10) experienced modest responses (0% cures but two- to threefold prolongation of survival compared with negative controls). In contrast, 70% of animals in the MRD lymphoma model demonstrated complete eradication of disease when treated with (211)At-B10-1F5 at a radiation dose that was less than one-third (15 µCi) of the highest dose given to xenograft animals. Tumor progression among untreated control animals in both models was uniformly lethal. After 130 days, no significant renal or hepatic toxicity was observed in the cured animals receiving 15 µCi of [(211)At]1F5-B10. These findings suggest that α-emitters are highly efficacious in MRD settings, where isolated cells and small tumor clusters prevail.

Mobilization and transplantation patterns of autologous hematopoietic stem cells in multiple myeloma and non-Hodgkin lymphoma

BACKGROUND

The mobilization of hematopoietic stem cells can be a limiting factor for transplantation, yet little is known about how the availability of novel mobilizing agents has affected the practices of oncologists and transplant specialists.

METHODS

US-based oncologists (n = 48) and transplant specialists (n = 46) were separately surveyed with a partial overlap of assessed information.

RESULTS

More transplant specialists than oncologists believed that the time between referral and first consultation is adequate (89.1% vs 54.2%; P < .001). The presence of comorbidities was the most common reason for patients not being referred for transplantation. Among oncologists, 31.3% avoided cyclophosphamide and 16.7% avoided lenalidomide to prevent mobilization impairment in patients with multiple myeloma (MM). Chemotherapy mobilization for MM was used by 23.9% of transplant specialists due to higher CD34+ yields and by 21.7% due to its anti-MM effect. In non-Hodgkin lymphoma (NHL), 26.1% of transplant specialists used chemotherapy mobilization due to higher CD34+ yields, and 26.1% collected hematopoietic stem cells on the rebound prior to chemotherapy. With regard to plerixafor use in MM, 36.9% of transplant specialists reported that they did not use it, and 28.3% said they reserved it for second mobilization. In NHL, 4.3% of transplant specialists reported not using plerixafor, and 39.1% reserved it for second mobilization.

CONCLUSIONS

Educational needs were identified to promote adequate referral for transplantation as well as successful and cost-effective methods for the mobilization of hematopoietic stem cells.

Clinical efficacy and safety in relapsed/refractory mantle cell lymphoma: a systematic literature review

A systematic literature review was performed to collect and review information on the clinical efficacy and safety of treatments for relapsed/refractory (R/R) mantle cell lymphoma (MCL), with a meta-analysis, if possible. PubMed, Embase, and the Cochrane Library were searched for studies published in English from January 1, 1997, to August 2, 2012. Conference proceedings, bibliographic reference lists of included articles, recent reviews, and ClinicalTrials.gov were searched for phase II to IV studies displaying results. Studies were included if they reported on patients with R/R MCL who were ineligible to receive high-dose chemotherapy with stem cell transplant. Studies of patients with several non-Hodgkin lymphoma subtypes were only included if they reported MCL outcomes separately. We identified 59 studies in R/R MCL. Forty distinct treatment regimens were evaluated. Thirty studies included more than 15 patients with R/R MCL. Six studies were comparative (including 5 randomized controlled trials [RCTs]); 53 were single-arm. There were no common treatments among the RCTs; therefore, a meta-analysis was not feasible. Thirty-one of 59 studies reported baseline data for patients with R/R MCL. Of the 30 studies with > 15 patients with R/R MCL, 30 reported overall response rate data, 14 reported progression-free survival (PFS), and 12 reported overall survival (OS). The small number of RCTs in R/R MCL precludes identifying an optimal treatment. Small sample sizes, infrequent reporting of OS and PFS, and limited information on patient characteristics made a comparison of results difficult. High-quality comparative studies of novel therapies that have the potential to demonstrate OS advantages in R/R MCL are needed.

Specific features identify patients with relapsed or refractory mantle cell lymphoma benefitting from autologous hematopoietic cell transplantation

Outcomes with autologous hematopoietic cell transplantation (auto HCT) for relapsed and/or refractory mantle cell lymphoma (MCL) are typically poor. We hypothesized that certain factors could predict which patients experience a favorable outcome with this approach. We thus developed a predictive score from a cohort of 67 such patients using 3 factors independently associated with progression-free survival (PFS): (1) simplified Mantle Cell Lymphoma International Prognostic Index score before auto HCT (hazard ratio [HR], 2.9; P = .002); (2) B symptoms at diagnosis (HR, 2.7; P = .005); and (3) remission quotient, calculated by dividing the time, in months, from diagnosis to auto HCT by the number of prior treatments (HR, 1.4; P = .02). The estimated 5-year PFS for favorable-risk patients (n = 23) and unfavorable-risk patients (n = 44) were 58% (95% confidence interval [CI], 34% to 75%) and 15% (95% CI, 6% to 28%), respectively. These factors also independently predicted overall survival. In summary, we have defined 3 simple factors that can identify patients with relapsed/refractory MCL who derive a durable benefit from salvage auto HCT.

Clinical practice guidelines for diagnosis, treatment, and follow-up of patients with mantle cell lymphoma. Recommendations from the GEL/TAMO Spanish Cooperative Group

Mantle cell lymphoma (MCL) is considered a distinct type of B-cell lymphoma genetically characterized by the t(11;14) translocation and cyclin D1 overexpression. There is also a small subset of tumors negative for cyclin D1 expression that are morphologically and immunophenotypically indistinguishable from conventional MCL. Although in the last decades, the median overall survival of patients with MCL has improved significantly, it is still considered as one of the poorest prognoses diseases among B-cell lymphomas. Election of treatment for patients with MCL is complex due to the scarcity of solid evidence. Current available data shows that conventional chemotherapy does not yield satisfactory results as in other types of B-cell lymphomas. However, the role of other approaches such as autologous or allogenic stem cell transplantation, immunotherapy, the administration of consolidation or maintenance schedules, or the use of targeted therapies still lack clear indications. In view of this situation, the Spanish Group of Lymphomas/Autologous Bone Marrow Transplantation has conducted a series of reviews on different aspects of MCL, namely its diagnosis, prognosis, first-line and salvage treatment (both in young and elderly patients), new targeted therapies, and detection of minimal residual disease. On the basis of the available evidence, a series of recommendations have been issued with the intention of providing guidance to clinicians on the diagnosis, treatment, and monitoring of patients with MCL.

Immune evasion of mantle cell lymphoma: expression of B7-H1 leads to inhibited T-cell response to and killing of tumor cells

Clinical trials of immunotherapy in mantle cell lymphoma have not yet delivered desirable results, partly because of the inhibitory machinery of the tumor and its microenvironment. Here we investigated the role of B7-H1, a member of the B7 family of co-stimulatory/co-inhibitory ligands, in mantle cell lymphoma-mediated immunosuppression. Allogeneic CD3(+), CD4(+) and CD8(+) T cells were purified and co-cultured with irradiated mantle cell lymphoma cells. Mantle cell lymphoma-reactive T-cell lines from HLA-A*0201(+) healthy blood donors were generated after in vitro restimulation, and were subjected to functional tests. We found that B7-H1 expressed on mantle cell lymphoma cells was able to inhibit T-cell proliferation induced by the tumor cells, impair the generation of antigen-specific T-cell responses, and render mantle cell lymphoma cells resistant to T-cell-mediated cytolysis. Blocking or knocking down B7-H1 on mantle cell lymphoma cells enhanced T-cell responses and restored tumor-cell sensitivity to T-cell-mediated killing in vitro and in vivo. Knocking down B7-H1 on mantle cell lymphoma cells primed more CD4(+) or CD8(+) memory effector T cells. Our study demonstrates for the first time that lymphoma cell-expressed B7-H1 may lead to the suppression of host anti-tumor immune responses in mantle cell lymphoma and targeting tumor cell B7-H1 may represent a novel approach to improve the efficacy of immunotherapy in patients with mantle cell lymphoma.

ESMO Consensus conferences: guidelines on malignant lymphoma. part 2: marginal zone lymphoma, mantle cell lymphoma, peripheral T-cell lymphoma

To complement the existing treatment guidelines for all tumour types, ESMO organizes consensus conferences to focus on specific issues in each type of tumour. In this setting, a consensus conference on the management of lymphoma was held on 18 June 2011 in Lugano, next to the 11th International Conference on Malignant Lymphoma. The conference convened ∼30 experts from all around Europe, and selected six lymphoma entities to be addressed; for each of them, three to five open questions were to be addressed by the experts. For each question, a recommendation should be given by the panel, referring to the strength of the recommendation based on the level of evidence. This consensus report focuses on the three less common lymphoproliferative malignancies: marginal zone lymphoma, mantle cell lymphoma, and peripheral T-cell lymphomas. A first report had focused on diffuse large B-cell lymphoma, follicular lymphoma, and chronic lymphocytic leukaemia.

Mechanism of the antitumoral activity of deferasirox, an iron chelation agent, on mantle cell lymphoma

Mantle cell lymphoma (MCL) characterized by the t(11;14)(q13;q32) translocation, resulting in cyclin D1 overexpression, is one of the most challenging lymphomas to treat. Iron chelators, such as deferasirox, have previously been shown to exhibit anti-proliferative properties; however, their effect on MCL cells has never been investigated. We showed that deferasirox exhibited antitumoral activity against the MCL cell lines HBL-2, Granta-519 and Jeko-1, with 50% inhibitory concentration (IC(50)) values of 7.99 ± 2.46 μM, 8.93 ± 2.25 μM and 31.86 ± 7.26 μM, respectively. Deferasirox induced apoptosis mediated through caspase-3 activation and decreased cyclin D1 protein levels resulting from increased proteasomal degradation. We also demonstrated down-regulation of phosphor-RB (Ser780) expression, which resulted in increasing levels of the E2F/RB complex and G(1)/S arrest. Finally, we showed that deferasirox activity was dependent on its iron chelating ability. The present data indicate that deferasirox, by down-regulating cyclin D1 and inhibiting its related signals, may constitute a promising adjuvant therapeutic molecule in the strategy for MCL treatment.

Optimized adoptive T-cell therapy for the treatment of residual mantle cell lymphoma

Mantle cell lymphoma (MCL) is an aggressive B-cell neoplasm with few patients achieving long-term survival with current treatment regimens. High-dose therapy is effective in reducing the tumor burden; however, patients eventually relapse due to minimal residual disease. Having demonstrated efficacy in other malignancies, the effectiveness of dendritic cell-based immunotherapy for minimal residual MCL was examined. We demonstrated that dendritic cells (DC) primed with MCL antigens stimulated the activation of MCL-specific T cells that recognized and destroyed both MCL cell lines and primary MCL in vitro. In addition, in vivo studies demonstrated that adoptively transferred MCL-specific T cells were able to significantly inhibit tumor growth in mice with minimal residual MCL. Subsequently, when combined with CHOP chemotherapy, adoptive T-cell therapy was able to significantly extend the survival of the mice by further reducing the tumor burden. These results clearly show that MCL-specific cellular immunotherapy is effective in treating minimal residual MCL, paving the way for future clinical studies.

Current treatment of mantle cell lymphoma: results of a national survey and consensus meeting

In most patients, mantle cell lymphoma (MCL) shows an aggressive clinical course with a continuous relapse pattern and a median survival of only 3-5 years. In the current study generation of the European MCL Network, the addition of high-dose Ara-C to R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine and prednisone)-like regimen followed by myeloablative consolidation achieved a significant improvement of progression-free survival in younger patients. In elderly patients, rituximab maintenance led to a marked prolongation of remission duration. Emerging strategies include mammalian target of rapamycin (mTOR) inhibitors, proteasome inhibitors, immune modulatory drugs, Bruton's tyrosine kinase inhibitors and others, all based on the dysregulated control of cell cycle machinery and impairment of several apoptotic pathways. Combination strategies are currently being investigated in numerous trials, but their introduction into clinical practice and current treatment algorithms remains a challenge. In the current survey, the application of the molecular targeted compounds were collected and evaluated by a representative national network of 14 haematological institutions. Optimised strategies are recommended for clinical routine. Future studies will apply individualised approaches according to the molecular risk profile of the patient.

Drug resistance to inhibitors of the human double minute-2 E3 ligase is mediated by point mutations of p53, but can be overcome with the p53 targeting agent RITA

The human double minute (HDM)-2 E3 ubiquitin ligase plays a key role in p53 turnover and has been validated preclinically as a target in multiple myeloma (MM) and mantle cell lymphoma (MCL). HDM-2 inhibitors are entering clinical trials, and we therefore sought to understand potential mechanisms of resistance in lymphoid models. Wild-type p53 H929 MM and Granta-519 MCL cells resistant to MI-63 or Nutlin were generated by exposing them to increasing drug concentrations. MI-63-resistant H929 and Granta-519 cells were resistant to Nutlin, whereas Nutlin-resistant cells displayed cross-resistance to MI-63. These cells also showed cross-resistance to bortezomib, doxorubicin, cisplatin, and melphalan, but remained sensitive to the small molecule inhibitor RITA (reactivation of p53 and induction of tumor cell apoptosis). HDM-2 inhibitor-resistant cells harbored increased p53 levels, but neither genotoxic nor nongenotoxic approaches to activate p53 induced HDM-2 or p21. Resequencing revealed wild-type HDM-2, but mutations were found in the p53 DNA binding and dimerization domains. In resistant cells, RITA induced a G(2)-M arrest, upregulation of p53 targets HDM-2, PUMA, and NOXA, and PARP cleavage. Combination regimens with RITA and MI-63 resulted in enhanced cell death compared with RITA alone. These findings support the possibility that p53 mutation could be a primary mechanism of acquired resistance to HDM-2 inhibitors in MCL and MM. Furthermore, they suggest that simultaneous restoration of p53 function and HDM-2 inhibition is a rational strategy for clinical translation.

Toll-like receptor-4 signaling in mantle cell lymphoma: effects on tumor growth and immune evasion

BACKGROUND

Mantle cell lymphoma (MCL) is an incurable B-cell malignancy, and patients with this disease have the poorest prognosis among all patients with B-cell lymphomas. The signaling pathways that trigger MCL escape from immune surveillance are unclear. Because Toll-like receptors (TLRs) initiate innate and adaptive immune responses against invading pathogens, the authors investigated the impact of TLR signaling in MCL cells.

METHODS

TLR expression was examined in MCL cell lines and in primary tumors. The examination focused on TLR4 and its ligand lipopolysaccharide (LPS) on MCL cells and their function on MCL proliferation and immune evasion.

RESULTS

MCL cells expressed multiple TLRs, and TLR4 was among the highest expressed molecules. The activation of TLR4 signaling in MCL cells by LPS induced MCL proliferation and up-regulated the secretion of cytokines like interleukin-6 (IL-6), IL-10, and vascular endothelial growth factor (VEGF). LPS-pretreated MCL cells inhibited the proliferation and cytolytic activity of T cells by secreted IL-10 and VEGF, and neutralizing antibodies against these cytokines restored their functions. Similar results were observed in TLR4-positive/myeloid differentiation 88 (MyD88)-positive primary lymphoma cells but not in TLR4-positive/MyD88-negative primary lymphoma cells from patients with MCL. Knockdown of TLR4 on MCL cells abrogated the effect of LPS on MCL cells in term of cell growth or secretion of the cytokines and evasion of the immune system.

CONCLUSIONS

The current results indicated that TLR4 signaling triggers a cascade that leads to MCL growth and evasion from immune surveillance. Thus, TLR4 signaling molecules may be novel therapeutic targets in patients with MCL.

Treatment of older patients with mantle-cell lymphoma

BACKGROUND

The long-term prognosis for older patients with mantle-cell lymphoma is poor. Chemoimmunotherapy results in low rates of complete remission, and most patients have a relapse. We investigated whether a fludarabine-containing induction regimen improved the complete-remission rate and whether maintenance therapy with rituximab prolonged remission.

METHODS

We randomly assigned patients 60 years of age or older with mantle-cell lymphoma, stage II to IV, who were not eligible for high-dose therapy to six cycles of rituximab, fludarabine, and cyclophosphamide (R-FC) every 28 days or to eight cycles of rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) every 21 days. Patients who had a response underwent a second randomization to maintenance therapy with rituximab or interferon alfa, each given until progression.

RESULTS

Of the 560 patients enrolled, 532 were included in the intention-to-treat analysis for response, and 485 in the primary analysis for response. The median age was 70 years. Although complete-remission rates were similar with R-FC and R-CHOP (40% and 34%, respectively; P=0.10), progressive disease was more frequent with R-FC (14%, vs. 5% with R-CHOP). Overall survival was significantly shorter with R-FC than with R-CHOP (4-year survival rate, 47% vs. 62%; P=0.005), and more patients in the R-FC group died during the first remission (10% vs. 4%). Hematologic toxic effects occurred more frequently in the R-FC group than in the R-CHOP group, but the frequency of grade 3 or 4 infections was balanced (17% and 14%, respectively). In 274 of the 316 patients who were randomly assigned to maintenance therapy, rituximab reduced the risk of progression or death by 45% (in remission after 4 years, 58%, vs. 29% with interferon alfa; hazard ratio for progression or death, 0.55; 95% confidence interval, 0.36 to 0.87; P=0.01). Among patients who had a response to R-CHOP, maintenance therapy with rituximab significantly improved overall survival (4-year survival rate, 87%, vs. 63% with interferon alfa; P=0.005).

CONCLUSIONS

R-CHOP induction followed by maintenance therapy with rituximab is effective for older patients with mantle-cell lymphoma. (Funded by the European Commission and others; ClinicalTrials.gov number, NCT00209209.).

[A case of mantle cell lymphoma with meningioma]

Mantle cell lymphoma (MCL) is an uncommon type of gastrointestinal lymphoma. MCL is a distinct subtype of B-cell non-Hodgkin lymphomas. The major subtype of MCL is characterized by the presence of multiple lymphomatous polyposis (MLP), in which multiple polyps are observed along the gastrointestinal tract. The malignant cells express pan B-cell marker and the T-cell marker cluster of differentiation 5. The chromosomal translocation t(11;14)(q13;q32) that causes cyclin D1 overexpression is commonly observed on the cytogenetic analysis of MCL. Survival improvement has recently been achieved for patient with MCL by the successful introduction of monoclonal antibodies and dose-intensified approaches for treatment, including autologous stem cell transplantation strategies. Some reports suggest that there is an increased incidence of second malignancies in patients with MCL or lymphoma. We report a case of MCL involving the colon; the patient was a 60-year-old man who complained of low abdominal discomfort during defecation. During the workup, a meningioma was unexpectedly discovered. On analysis, the tumor was found to be a t(11;14)-negative and non-MLP-type MCL.

Mantle cell lymphoma: a clinically heterogeneous disease in need of tailored approaches

BACKGROUND

Mantle cell lymphoma (MCL) remains incurable using conventional chemotherapeutic approaches. New clinical data show that some patients have a chronic/indolent course and others have a more fulminant course and short survival, similar to that of patients with acute leukemias.

METHODS

This review presents an overview of this aggressive disease, including the diagnosis, epidemiology, prognosis, and management of this protean and challenging condition.

RESULTS

Distinguishing indolent MCL from in situ MCL is important but can be challenging. Molecular exploration has identified SOX11 and HDAC11 as potential candidate genes for discrimination of indolent cases. Improvements in the prognosis in MCL are likely the result of earlier identification of more indolent cases and the application of modern modalities, including rituximab and autologous transplantation. Younger patients may be able to tolerate more intensive therapy, while treatment for elderly or frail patients may focus on maintenance to prolong remission. For patients with relapsed disease, some agents have shown promise, such as lenalidomide and bortezomib. Emerging drugs such as PCI37625 and CAL-101 are being explored in phase I and II studies.

CONCLUSIONS

Although patients with MCL continue to experience poor outcomes, new treatment approaches for various stages of disease are showing promise in improving survival.

A retrospective study evaluating the efficacy and safety of bendamustine in the treatment of mantle cell lymphoma

Bendamustine is approved in the United States for relapsed indolent lymphoma. However, it has not been widely studied in mantle cell lymphoma (MCL). We retrospectively reviewed the records of all patients with MCL who were treated with bendamustine at three centers. The primary endpoint was overall response rate (ORR). Thirty patients with MCL received bendamustine, 25 for relapsed disease. After a median follow-up of 12 months, there were 15 complete responses (CRs) with an ORR of 83% (95% confidence interval [CI] 70-97%). Factors significantly associated with longer survival were achieving a CR and classical (versus blastic) variant of MCL. Grade 3 or 4 neutropenia, anemia and thrombocytopenia occurred in 23%, 3% and 20%, respectively. There was one case of progressive multifocal leukoencephalopathy 10 months after therapy completion. Bendamustine in combination with rituximab demonstrated a high response rate in this study of patients with predominantly relapsed MCL.

Establishment and characterization of therapy-resistant mantle cell lymphoma cell lines derived from different tissue sites

Mantle cell lymphoma (MCL) is a rare but aggressive form of B cell non-Hodgkin lymphoma in which therapy resistance is common. New therapeutic options have extended survival in refractory MCL but have not provided durable remission. Tools are needed to assess the molecular and genetic changes associated with therapy resistance. Therefore, therapy-resistant MCL cell lines were established from the liver, kidney and lungs of human Granta 519-bearing NOD-SCID (non-obese diabetic-severe combined immunodeficiency) mice following treatment with CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone) chemotherapy in combination with bortezomib. The cytomorphologies, immunophenotypes, growth patterns in semi-solid agar, cytogenetic profiles and gene expression differences between these cell lines were characterized to identify major changes associated with therapy resistance. Therapy-resistant cell lines exhibit more aggressive growth patterns and markedly different gene expression profiles compared to parental Granta 519 cells. Thus, these stable therapy-resistant cell lines are useful models to further study the molecular basis of drug resistance and to identify clinically relevant molecular targets in MCL.

Allogeneic hematopoietic cell transplantation in mantle cell lymphoma

Mantle cell lymphoma (MCL) is a high-risk non-Hodgkin lymphoma that is considered incurable with standard chemotherapy. While autologous hematopoietic cell transplantation (autoHCT) can provide lengthy disease-free survival in select patients, cure generally is not an expected outcome with this approach. Allogeneic hematopoietic cell transplantation (alloHCT), which can exploit the potential benefits of graft-versus-lymphoma (GVL) effect, has been shown in multiple studies to yield a small but reproducible portion of patients with long-term remission more suggestive of cure. Historically, alloHCT for MCL was administered after myeloablative conditioning, but this approach was limited by early non-relapse mortality. Development of reduced-intensity (RI)-alloHCT has abrogated some of the early post-transplant risks, allowing this potentially effective therapy to be offered to a larger number of affected individuals. The trends in published data reflect a preference toward using RI-alloHCT for MCL, often because patients in whom alloHCT is being considered have relapsed disease following myeloablative autoHCT. Further efforts to spare the effects of graft-versus-host disease (GVHD) while still evoking GVL remain a focus of investigation in this area. In this review, we will discuss the application of alloHCT in the management of MCL, the factors associated with outcome, the different methods in which it can be performed, and the strategies that can be employed in post-alloHCT relapse.

Prognostic role of SOX11 in a population-based cohort of mantle cell lymphoma

The prognostic role of the transcription factor SOX11 in mantle cell lymphoma (MCL) is controversial. We investigated prognostic markers in a population-based cohort of 186 MCL cases. Seventeen patients (9%) did not require any therapy within the first 2 years after diagnosis and were retrospectively defined as having an indolent disease. As expected, indolent MCL had less frequent B symptoms and extensive nodal involvement and 88% of these cases expressed SOX11. In our cohort 13 cases (7.5%) lacked nuclear SOX11 at diagnosis. SOX11− MCL had a higher frequency of lymphocytosis, elevated level of lactate dehydrogenase (LDH), and p53 positivity. The overall survival in the whole cohort, excluding 37 patients receiving autologous stem cell transplantation, was 3.1 year and in patients with indolent or nonindolent disease, 5.9 and 2.8 years, respectively (P = .004). SOX11− cases had a shorter overall survival, compared with SOX11+ cases, 1.5 and 3.2 years, respectively (P = .014). In multivariate analysis of overall survival, age > 65 (P = .001), Eastern Cooperative Oncology Group score ≥ 2 (P = .022), elevated LDH level (P = .001), and p53 expression (P = .001) remained significant, and SOX11 lost significance. We conclude that most indolent MCLs are SOX11+ and that SOX11 cannot be used for predicting an indolent disease course.

Who should be really considered as a poor mobilizer in the plerixafor era?

Patients with a number of peripheral CD34+ cells ≥20/μL have recently been defined in the literature as "poor mobilizers". We retrospectively reviewed medical records from a total of 248 patients affected by hematological malignancies or solid tumors undergoing peripheral blood stem cell collection following chemotherapy plus G-CSF. On the basis of the CD34+ cell peak in peripheral blood following mobilization therapy, patients were defined as good mobilizers (group A, CD34+ cells ≥20/μL), relative poor mobilizers (group B, CD34+ cells <20 and ≥8/μL) and absolute poor mobilizers (group C, CD34+ cells <8/μL). One hundred and seventy-seven (71%) patients resulted good mobilizers, 35 (14%) patients relative poor mobilizers and 36 (15%) patients absolute poor mobilizers. Target of stem cell collection was ≥2.0×10(6) CD34+cells/kg for each transplantation procedure. All patients in group A, 20 patients in group B (57%) and 1 patient in group C (2.7%) were able to collect ≥2.0×10(6) CD34+cells/kg. The multivariate analysis confirmed that more than three lines of previous chemotherapy and a previous autologous PBSC transplantation negatively affect mobilization of CD34+ cells in peripheral blood. Our data suggest that a number of CD34+ cells ≥20/μL does not always result in a failed stem cell collection and in fact in our patient series more than 70% of the patients defined as poor mobilizers have indeed collected the minimum number of 2.0×10(6) CD34+cells/kg required for a successful transplantation. The use of new agent such as CXCR4 antagonist plerixafor might further improve mobilization efficacy in such patients.

Relapsed and/or Refractory Mantle Cell Lymphoma: What Role for Temsirolimus?

Mantle Cell Lymphoma (MCL) is associated with a dismal prognosis. Recently, along with the improved understanding of the pathophysiology of this disease, new first line regimens have been established and in addition novel treatment options have entered the clinical arena. In consequence, prognosis of the disease has fortunately improved. We here focus on the rationale, current clinical knowledge and future concepts of Temsirolimus, an inhibitor of mTOR, in the treatment of MCL. At this time this drug has been shown to be effective as single agent for relapsed disease and early combination data show promising results. In addition, with a brief outline of other treatment options, we aim to guide at which place in the current treatment algorithms Temsirolimus can be integrated into the treatment of MCL patients.

The proteasome inhibitor bortezomib targets cell cycle and apoptosis and acts synergistically in a sequence-dependent way with chemotherapeutic agents in mantle cell lymphoma

Single-agent bortezomib, a potent, selective, and reversible inhibitor of the 26S proteasome, has demonstrated clinical efficacy in relapsed and refractory mantle cell lymphoma (MCL). Objective response is achieved in up to 45% of the MCL patients; however, complete remission rates are low and duration of response proved to be relatively short. These limitations may be overcome by combining proteasome inhibition with conventional chemotherapy. Rational combination treatment and schedules require profound knowledge of underlying molecular mechanisms. Here we show that single-agent bortezomib treatment of MCL cell lines leads to G2/M arrest and induction of apoptosis accompanied by downregulation of EIF4E and CCND1 mRNA but upregulation of p15(INK4B) and p21 mRNA. We further present synergistic efficacy of bortezomib combined with cytarabine in MCL cell lines. Interestingly this sequence-dependent synergistic effect was seen almost exclusively in combination with AraC, indicating that pretreatment with cytarabine, followed by proteasome inhibition, may be the preferred approach.

Molecular targeted approaches in mantle cell lymphoma

Mantle cell lymphoma (MCL) is a malignancy of mature B cells characterized by the translocation t(11;14) that leads to aberrant expression of cyclin D1. Response to first-line chemotherapy is good, but most patients relapse, resulting in a median survival of 5 to 7 years. The important PI3K/AKT/mTOR pathway can be targeted with small molecules. mTOR inhibitors have clinical activity and temsirolimus has been approved in Europe. Second-generation mTOR inhibitors and the PI3K inhibitor CAL-101 offer additional means to target the pathway. Promising results with the BTK inhibitor PCI-32765 suggest that B-cell receptor signaling could play a role. For unknown reasons, MCL appears to be particularly sensitive to disruption of protein homeostasis. The proteasome inhibitor bortezomib achieves responses in up to 50% of relapsed patients. Much work has been done in elucidating the mechanism of its cytotoxicity, its incorporation into combination therapies, and the development of second-generation proteasome inhibitors. Deacetylase and HSP90 inhibitors are also promising classes of drugs that can synergize with proteasome inhibitors. Finally, BH3 mimetics are emerging as tools to sensitize tumor cells to chemotherapy. Participation in clinical trials offers patients an immediate chance to benefit from these advances and is essential to maintain the momentum of progress.

Solitary primary gastric mantle cell lymphoma

Mantle cell lymphoma (MCL) is a relatively rare subgroup of non-Hodgkin's lymphoma that is characterized by an aggressive and severe disease course with frequent involvement of regional lymph nodes and/or early metastasis. Because most cases of MCL are diagnosed in the advanced stages, clinical data on extranodal or early stage MCL is lacking, and MCL that is both extranodal and diagnosed during the early stages is even more rare. There have been several case reports on primary gastric MCL, which comprise a type of extranodal MCLs. However, to our knowledge, there have been no reports on solitary primary gastric MCL without regional lymph node involvement or distant metastasis. Recently, the authors experienced an uncommon case of MCL with the aforementioned characteristics that was managed with chemotherapy followed by allogenic stem cell transplantation.