How to manage mantle cell lymphoma

Combined epigenetic and immunotherapy for blastic and classical mantle cell lymphoma

Classical MCL (cMCL) constitutes 6-8% of all B cell NHL. Despite recent advances, MCL is incurable except with allogeneic stem cell transplant. Blastic mantle cell lymphoma (bMCL) is a rarer subtype of cMCL associated with an aggressive clinical course and poor treatment response, frequent relapse and poor outcomes. We treated 13 bMCL patients with combined epigenetic and immunotherapy treatment consisting of vorinostat, cladribine and rituximab (SCR). We report an increased OS greater than 40 months with several patients maintaining durable remissions without relapse for longer than 5 years. This is remarkably better then current treatment regimens which in bMCL range from 14.5-24 months with conventional chemotherapy regimens. We demonstrate that the G/A870 CCND1 polymorphism is predictive of blastic disease, nuclear localization of cyclinD1 and response to SCR therapy. The major resistance mechanisms to SCR therapy are loss of CD20 expression and evasion of treatment by sanctuary in the CNS. These data indicate that administration of epigenetic agents improves efficacy of anti-CD20 immunotherapies. This approach is promising in the treatment of MCL and potentially other previously treatment refractory cancers.

Targeted Locus Amplification as Marker Screening Approach to Detect Immunoglobulin (IG) Translocations in B-Cell Non-Hodgkin Lymphomas

Although MRD monitoring by the classic polymerase chain reaction (PCR) approach is a powerful outcome predictor, about 20% of mantle cell lymphoma (MCL) and 50% of follicular lymphoma (FL) patients still lack a molecular marker and are thus resulting not eligible for MRD monitoring. Targeted locus amplification (TLA), a new NGS technology, has been revealed as a feasible marker screening approach able to identify uncommon B-cell leukemia/lymphoma 1 (BCL1) and B-cell leukemia/lymphoma 2 (BCL2) rearrangements in MCL and FL cases defined as having "no marker" by the classic PCR approach.

The Effectiveness of Dual-Staining Immunohistochemistry in the Detection of Mantle Cell Lymphoma in the Bone Marrow

OBJECTIVES

Immunohistochemistry (IHC) is a useful method for mantle cell lymphoma (MCL) detection in the bone marrow (BM). However, recognition of the neoplastic B cells can be challenging, especially when there is low-level disease.

METHODS

We examined BM from 105 patients with MCL. IHC was performed using cyclin D1/CD79a and PAX5/CD5 dual stains, which were compared with single stains that included CD20, CD79a, cyclin D1, and CD5 and with multiparameter flow cytometry (FC).

RESULTS

Based on the FC data, the overall sensitivity of the dual IHC stains was 95.6%. Both dual IHC stains showed better efficacy for detecting MCL cells compared with the aggregated single stains (P = .012). While three cases were positive by FC analysis but negative for dual staining, four cases showed cells positive for cyclin D1/CD79a and PAX5/CD5 dual staining that were not detected by FC. Two of these latter cases were in patients with minimal or focal disease involvement.

CONCLUSIONS

Cyclin D1/CD79a and PAX5/CD5 dual IHC staining is an efficient procedure for the detection of MCL in the marrow and is particularly helpful in low-level or focal involvement by MCL. This approach can be particularly useful when marrow aspirates are inadequate or unavailable.

A Clinical Prognostic Model Based on Machine Learning from the Fondazione Italiana Linfomi (FIL) MCL0208 Phase III Trial

BACKGROUND

Multicenter clinical trials are producing growing amounts of clinical data. Machine Learning (ML) might facilitate the discovery of novel tools for prognostication and disease-stratification. Taking advantage of a systematic collection of multiple variables, we developed a model derived from data collected on 300 patients with mantle cell lymphoma (MCL) from the Fondazione Italiana Linfomi-MCL0208 phase III trial (NCT02354313).

METHODS

We developed a score with a clustering algorithm applied to clinical variables. The candidate score was correlated to overall survival (OS) and validated in two independent data series from the European MCL Network (NCT00209222, NCT00209209); Results: Three groups of patients were significantly discriminated: Low, Intermediate (Int), and High risk (High). Seven discriminants were identified by a feature reduction approach: albumin, Ki-67, lactate dehydrogenase, lymphocytes, platelets, bone marrow infiltration, and B-symptoms. Accordingly, patients in the Int and High groups had shorter OS rates than those in the Low and Int groups, respectively (Int→Low, HR: 3.1, 95% CI: 1.0-9.6; High→Int, HR: 2.3, 95% CI: 1.5-4.7). Based on the 7 markers, we defined the engineered MCL international prognostic index (eMIPI), which was validated and confirmed in two independent cohorts; Conclusions: We developed and validated a ML-based prognostic model for MCL. Even when currently limited to baseline predictors, our approach has high scalability potential.

Treatment patterns and outcomes of unfit and elderly patients with Mantle cell lymphoma unfit for standard immunochemotherapy: A UK and Ireland analysis

Mantle cell lymphoma (MCL) presenting in elderly, unfit patients represents a clinical challenge. Front-line 'attenuated' or low-intensity immunochemotherapy is often employed, although outcomes are relatively unexplored. We report outcomes of attenuated immunochemotherapy in 95 patients with MCL across 19 centres in the UK and Ireland considered unfit for full-dose rituximab-bendamustine or rituximab-cyclophosphamide, doxorubicin, vincristine, prednisolone (R-CHOP). Regimens examined were rituximab-cyclophosphamide, vincristine, prednisolone (R-CVP) (n = 19), dose-attenuated R-CHOP (n = 22), dose attenuated rituximab-bendamustine (n = 24) and rituximab-chlorambucil (n = 30). The primary outcome was progression-free survival (PFS). The secondary outcomes included overall response, overall survival (OS) and toxicity. The median (range) age was 79 (58-89) years and 50% were aged ≥80 years. The median (range) Cumulative Illness Rating Scale-Geriatric score was 6 (0-24). The median PFS for all patients was 15 months [95% confidence interval (CI) 8·7-21·2) and median OS was 31·4 months (95% CI 19·7-43·2). By multivariable analysis (MVA), the only clinical factor associated with an inferior PFS was blastoid morphology [hazard ratio (HR) 2·90, P = 0·01). Notably, higher treatment intensity (R-CHOP/R-bendamustine composite) provided an independently superior PFS compared with R-CVP/R-chlorambucil (MVA HR 0·49, P = 0·02). Factors associated with inferior OS by MVA were Eastern Cooperative Oncology Group Performance Status (HR 2·14, P = 0·04), blastoid morphology (HR 4·08, P = 0·001) and progression of disease at <24 months status (HR 5·68, P < 0·001). Overall, survival after front-line dose-attenuated immunochemotherapy is unsatisfactory. Clinical trials investigating novel agents such as Bruton tyrosine kinase and B-cell lymphoma 2 inhibitors in this specific clinical setting are warranted.

Targeted locus amplification to detect molecular markers in mantle cell and follicular lymphoma

Minimal residual disease (MRD) monitoring by PCR methods is a strong and standardized predictor of clinical outcome in mantle cell lymphoma (MCL) and follicular lymphoma (FL). However, about 20% of MCL and 40% of FL patients lack a reliable molecular marker, being thus not eligible for MRD studies. Recently, targeted locus amplification (TLA), a next‐generation sequencing (NGS) method based on the physical proximity of DNA sequences for target selection, identified novel gene rearrangements in leukemia. The aim of this study was to test TLA in MCL and FL diagnostic samples lacking a classical, PCR‐detectable, t(11; 14) MTC (BCL1/IGH), or t(14; 18) major breakpoint region and minor cluster region (BCL2/IGH) rearrangements. Overall, TLA was performed on 20 MCL bone marrow (BM) or peripheral blood (PB) primary samples and on 20 FL BM, identifying a novel BCL1 or BCL2/IGH breakpoint in 16 MCL and 8 FL patients (80% and 40%, respectively). These new breakpoints (named BCL1‐TLA and BCL2‐TLA) were validated by ASO primers design and compared as MRD markers to classical IGH rearrangements in eight MCL: overall, MRD results by BCL1‐TLA were superimposable (R Pearson = 0.76) to the standardized IGH‐based approach. Moreover, MRD by BCL2‐TLA reached good sensitivity levels also in FL and was predictive of a primary refractory case. In conclusion, this study offers the proof of principle that TLA is a promising and reliable NGS‐based technology for the identification of novel molecular markers, suitable for further MRD analysis in previously not traceable MCL and FL patients.

Immunoglobulin kappa deleting element rearrangements are candidate targets for minimal residual disease evaluation in mantle cell lymphoma

Minimal residual disease (MRD) assessment is of high clinical relevance in patients with mantle cell lymphoma (MCL). In mature B-cell malignancies, the presence of somatic hypermutations (SHM) in Variable-Diversity-Joining Heavy chain (VDJH) rearrangements leads to frequent mismatches between primers, probes, and the target, thus impairing tumor cells quantification. Alternative targets, such as immunoglobulin kappa-deleting-element (IGK-Kde) rearrangements, might be suitable for MRD detection. We aimed at evaluating the applicability of IGK-Kde rearrangements for MRD quantification in MCL patients by real-time quantitative polymerase chain reaction (RQ-PCR)/digital-droplet-PCR (ddPCR). IGK screening was performed on bone marrow samples from two cohorts: the first from Turin (22 patients enrolled in the FIL-MCL0208 trial, NCT02354313) and the second from Rome (15 patients). IGK-Kde rearrangements were found in 76% (28/37) of cases, representing the sole molecular marker in 73% (8/11) of IGH-BCL1/IGH negative cases. MRD RQ-PCR monitoring was possible in 57% (16/28) of cases, showing a 100% concordance with the conventional targets. However, the frequent background amplification affected the sensitivity of the assay, that was lower in MCL compared to acute lymphoblastic leukemia and in line with multiple myeloma published results. ddPCR had a good concordance with RQ-PCR and it might help to identify false positive/negative results. From a clinical perspective, we suggest that IGK-Kde can be a candidate target for MRD monitoring and deserves a validation of its predictive value in prospective MCL series.

Treatment of Older Patients With Mantle Cell Lymphoma (MCL): Long-Term Follow-Up of the Randomized European MCL Elderly Trial

PURPOSE

In an update of the randomized, open-label, phase III European Mantle Cell Lymphoma (MCL) Elderly trial (ClinicalTrials.gov identifier: NCT00209209), published in 2012, we aimed to confirm results on long-term outcome focusing on efficacy and safety of long-term use of rituximab maintenance.

PATIENTS AND METHODS

Five hundred sixty patients with newly diagnosed MCL underwent a first random assignment between rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) and rituximab, fludarabine, and cyclophosphamide (R-FC) induction, followed by a second random assignment in 316 responders between rituximab and interferon alfa maintenance, to be continued until progression. We compared progression-free survival from the second randomization and overall survival (OS) from the first or second randomizations.

RESULTS

After a median follow-up time of 7.6 years, the previously described difference in OS between the induction arms persisted (median, 6.4 years after R-CHOP [n = 280] v 3.9 years after R-FC [n = 280]; P = .0054). Patients responding to R-CHOP had median progression-free survival and OS times of 5.4 and 9.8 years, respectively, when randomly assigned to rituximab (n = 87), compared with 1.9 years (P < .001) and 7.1 years (P = .0026), respectively, when randomly assigned to interferon alfa (n = 97). In 58% and 32% of patients treated with R-CHOP, rituximab maintenance was still ongoing 2 and 5 years from start of maintenance, respectively. After R-FC, rituximab maintenance was associated with an unexpectedly high cumulative incidence of death in remission (22% at 5 years). Toxicity of rituximab maintenance was low after R-CHOP (grade 3-4 leukopenia or infection < 5%) but more prominent in patients on rituximab maintenance after R-FC, in whom grade 3-4 leukopenia (up to 40%) and infections were frequent (up to 15%).

CONCLUSION

The excellent results of R-CHOP followed by rituximab maintenance until progression for older patients with MCL persisted in a mature follow-up. Prolongation of rituximab maintenance beyond 2 years is effective and safe.

Prognostic impact of interim positron emission tomography in mantle cell lymphoma patients treated with frontline R-CHOP

Although ¹⁸F‐fluorodeoxyglucose positron emission tomography (¹⁸F‐FDG PET) is commonly used for initial staging and therapeutic response evaluation in aggressive lymphomas, its prognostic utility for mantle cell lymphoma (MCL) is controversial. Therefore, we retrospectively evaluated the correlations of interim PET (iPET) and end‐of‐treatment PET (ePET) response with survival outcomes in 89 consecutive advanced MCL patients treated with frontline R‐CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine and prednisolone). iPET positivity was strongly associated with inferior five‐year overall survival (OS) [hazard ratio (HR) 7·84, P < 0·0001] and poor five‐year progression‐free survival (PFS) (HR 3·34, P < 0·0001). OS and PFS were more favourable in the order early metabolic responder (iPET^neg → ePET^neg), delayed responder (iPET^pos → ePET^neg), loss‐metabolic responder (iPET^neg → ePET^pos), and never‐metabolic responder (iPET^pos → ePET^pos). In the autologous haematopoietic stem cell transplantation (auto‐HSCT)‐fit subgroup, OS was more favourable in the order early metabolic responders, delayed metabolic responders, and non‐metabolic responders, with a marginal trend toward statistical significance (HR 3·41, P = 0·051), and PFS was significantly superior in early metabolic responders (HR 4·43, P = 0·002). In a group that was ineligible for auto‐HSCT, OS and PFS were significantly superior in early metabolic responders. Our results suggested that iPET is of prognostic value and an independent predictor of survival in MCL patients receiving frontline R‐CHOP. Therefore, prospective clinical trials of iPET‐guided treatment strategies for these patients are warranted.

Applying Data Warehousing to a Phase III Clinical Trial From the Fondazione Italiana Linfomi Ensures Superior Data Quality and Improved Assessment of Clinical Outcomes

PURPOSE

Data collection in clinical trials is becoming complex, with a huge number of variables that need to be recorded, verified, and analyzed to effectively measure clinical outcomes. In this study, we used data warehouse (DW) concepts to achieve this goal. A DW was developed to accommodate data from a large clinical trial, including all the characteristics collected. We present the results related to baseline variables with the following objectives: developing a data quality (DQ) control strategy and improving outcome analysis according to the clinical trial primary end points.

METHODS

Data were retrieved from the electronic case reporting forms (eCRFs) of the phase III, multicenter MCL0208 trial (ClinicalTrials.gov identifier: NCT02354313) of the Fondazione Italiana Linfomi for younger patients with untreated mantle cell lymphoma (MCL). The DW was created with a relational database management system. Recommended DQ dimensions were observed to monitor the activity of each site to handle DQ management during patient follow-up. The DQ management was applied to clinically relevant parameters that predicted progression-free survival to assess its impact.

RESULTS

The DW encompassed 16 tables, which included 226 variables for 300 patients and 199,500 items of data. The tool allowed cross-comparison analysis and detected some incongruities in eCRFs, prompting queries to clinical centers. This had an impact on clinical end points, as the DQ control strategy was able to improve the prognostic stratification according to single parameters, such as tumor infiltration by flow cytometry, and even using established prognosticators, such as the MCL International Prognostic Index.

CONCLUSION

The DW is a powerful tool to organize results from large phase III clinical trials and to effectively improve DQ through the application of effective engineered tools.

Clinical outcomes for ibrutinib in relapsed or refractory mantle cell lymphoma in real-world experience

Ibrutinib is highly effective in patients with relapsed or refractory mantle cell lymphoma (MCL) in major clinical trials. Although there has been a dramatic improvement in survival outcomes in the salvage setting, nonresponders to ibrutinib have a bleak prognosis. Therefore, this retrospective study was conducted to identify the most appropriate therapeutic strategy and prognosis‐related factors to predict the response of patients with relapsed or refractory MCL to ibrutinib monotherapy. Thirty‐three consecutive refractory or relapsed MCL patients treated with ibrutinib were analyzed in this study. The median overall survival (OS) and progression‐free survival (PFS) after initiation of ibrutinib were 35.1 months and 27.4 months, respectively. Risk factor analysis showed that high risk according to the Mantle Cell Lymphoma International Prognostic Index (MIPI) and nonresponse to ibrutinib at the first three cycles were significantly associated with inferior OS. Poor PFS was associated with high‐risk biologic MIPI, prior bendamustine exposure, and nonresponse to ibrutinib during the first three cycles. After ibrutinib failure, primary nonresponders had poorer OS and PFS than inconsistent responders. The overall response rate for the first salvage therapy was only 33%, with a median TTP of 3.2 months. There was no effective therapeutic strategy except for allogeneic hematopoietic stem cell transplantation (allo‐HSCT). Although ibrutinib responders exhibited favorable survival outcomes, nonresponders had a dismal prognosis. To overcome these limitations, it may be necessary to modify therapeutic strategies, such as selecting inconsistent responders for earlier allo‐HSCT.

Spontaneous Regression of Clinically Indolent Lymphomas Revealed by 18F-FDG PET/CT

A 48-year-old man and a 55-year-old woman, who were diagnosed with follicular lymphoma and small B lymphocytic cell lymphoma, respectively, underwent initial "watch-and-wait" approach against lymphoma. The initial F-FDG PET/CT of both patients showed multiple FDG-avid lymph nodes in the neck, mediastinum, abdomen, and inguinal regions. During their active surveillance, the follow-up PET/CT of both patients revealed spontaneous regression of lymphoma.

New and emerging Bruton tyrosine kinase inhibitors for treating mantle cell lymphoma - where do they fit in?

INTRODUCTION

Despite recent prognostic improvements, mantle cell lymphoma (MCL) remains incurable. Bruton tyrosine kinase (BTK) is a key receptor in B-cell tumorigenesis, and the benefits of the first BTK inhibitor, ibrutinib, are becoming clear in MCL. However, off-target activities, which contribute to ibrutinib-related adverse events, suggest potential for further improvement of this drug class. Areas covered: The authors systematically interrogated ClinicalTrials.gov for trials containing keywords for BTK and MCL. Published literature for new and emerging BTK inhibitors being investigated in MCL was then identified (PubMed and Embase), summarized, and placed in the context of treatment guidelines. Expert commentary: Reduced off-target effects of new and emerging covalent, irreversible BTK inhibitors under investigation in patients with MCL offer the potential of improved safety compared with ibrutinib. Efficacy may also be favorable based on trial data for acalabrutinib, which has just been approved in the USA as second-line therapy for MCL. The role of BTK inhibitors in treating MCL will evolve substantially over the coming years as results from a number of trials become available, particularly in relation to potential upfront use and possible synergy with other targeted therapies such as B-cell lymphoma 2, phosphoinositide 3-kinase and checkpoint inhibitors.

Paclitaxel synergizes with exposure time adjusted CD22-targeting immunotoxins against B-cell malignancies

CD22-targeted recombinant immunotoxins (rIT) are active in hairy cell leukemia or acute lymphoblastic leukemia (ALL), but not in mantle cell lymphoma (MCL) patients. The goal was to enhance rIT efficacy in vivo and to define a strong combination treatment. Activity of Moxetumomab pasudotox (Moxe) and LR combined with paclitaxel was tested against MCL cell lines in vitro and as bolus doses or continuous infusion in xenograft models. In the KOPN-8 ALL xenograft, Moxe or paclitaxel alone was active, but all mice died from leukemia; when combined, 60% of the mice achieved a sustained complete remission. Against MCL cells in vitro, LR was more active than Moxe and the cells had to be exposed to rIT for more than 24 hours for them to die. To maintain high blood levels in vivo, LR was administered continuously by 7-day pumps achieving a well-tolerated steady plasma concentration of 45 ng/ml. In JeKo-1 xenografts, continuously administered LR was 14-fold more active than bolus doses and the combination with paclitaxel additionally improved responses by 135-fold. Maintaining high rIT-plasma levels greatly improves responses in the JeKo-1 model and paclitaxel substantially enhances bolus and continuously infused rIT, supporting a clinical evaluation against B-cell malignancies.

A B-cell receptor-related gene signature predicts survival in mantle cell lymphoma: results from the Fondazione Italiana Linfomi MCL-0208 trial

Mantle cell lymphoma patients have variable clinical courses, ranging from indolent cases that do not require immediate treatment to aggressive, rapidly progressing diseases. Thus, diagnostic tools capable of stratifying patients according to their risk of relapse and death are needed. This study included 83 samples from the Fondazione Italiana Linfomi MCL-0208 clinical trial. Through gene expression profiling and quantitative real-time PCR we analyzed 46 peripheral blood and 43 formalin-fixed paraffin-embedded lymph node samples. A prediction model to classify patients was developed. By analyzing the transcriptome of 27 peripheral blood samples, two subgroups characterized by a differential expression of genes from the B-cell receptor pathway (B-cell receptor^low and B-cell receptor^high) were identified. The prediction model based on the quantitative real-time PCR values of six representative genes (AKT3, BCL2, BTK, CD79B, PIK3CD, and SYK), was used to classify the 83 cases (43 B-cell receptor^low and 40 B-cell receptor^high). The B-cell receptor^high signature associated with shorter progression-free survival (P=0.0074), selected the mantle cell lymphoma subgroup with the shortest progression-free survival and overall survival (P=0.0014 and P=0.029, respectively) in combination with high (>30%) Ki-67 staining, and was an independent predictor of short progression- free survival along with the Mantle Cell Lymphoma International Prognostic Index-combined score. Moreover, the clinical impact of the 6- gene signature related to the B-cell receptor pathway identified a mantle cell lymphoma subset with shorter progression-free survival intervals also in an external independent mantle cell lymphoma cohort homogenously treated with different schedules. In conclusion, this 6-gene signature associates with a poor clinical response in the context of the MCL- 0208 clinical trial. (clinicaltrials.gov identifier: 02354313).

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.

A Systematic Review of Treatments of Relapsed/Refractory Mantle Cell Lymphoma

A systematic review was conducted to evaluate the clinical effectiveness and safety of treatments for patients with relapsed/refractory mantle cell lymphoma (MCL) unsuitable for intensive treatment. The criteria for inclusion of the trials were established before the review. A search of Medline, Embase, and the Cochrane library databases was conducted to identify phase II or III randomized controlled trials (RCTs), reported from January 1, 1994 to May 29, 2016. Relevant conference abstracts, citation lists from the included articles, published guidelines, and on-going clinical trial databases were also searched. Studies were included if they had evaluated any single agent or combination of treatments for adult patients with relapsed/refractory MCL who had received ≥ 1 previous line of therapy. Seven RCTs were identified. Only 1 treatment appeared in > 1 trial; therefore, the results from each trial could not be quantitatively pooled for meta-analysis. The lack of common comparators, differences in baseline characteristics and inclusion and exclusion criteria, and variances in the response criteria used to measure outcomes made comparison of the results difficult. Although the direction of effect for progression-free survival (PFS) and overall survival (OS) was in favor of the experimental drug in all trials, the difference in PFS was statistically significant in 5 and OS in 2. None showed statistical significance for both. A noticeable lack of RCTs evaluating treatments for patients with relapsed/refractory MCL made meaningful comparisons of effectiveness across trials rather difficult. This trend continues, because all, bar 1, of the 85 ongoing trials in this area are single-arm studies. RCTs are required to enable better evaluation of the optimal treatment regimen for this group of patients.

Concise Review: Emerging Principles from the Clinical Application of Chimeric Antigen Receptor T Cell Therapies for B Cell Malignancies

Gene-engineered T cell therapies are soon to be United States Food and Drug Administration (FDA) approved for at least two types of B cell malignancies in pediatric and adult patients, in the form of CD19 targeted chimeric antigen receptor T (CAR T) cell therapy. This represents a triumph of a true bench to bedside clinical translation of a therapy that was conceived of in the early 1990s. Clinical results have demonstrated efficacious responses in patients with the CD19 positive diseases B cell acute lymphoblastic leukemia and diffuse large B cell lymphoma. However, significant challenges have emerged, including worrisome immune-related toxicities, therapy resistance, and understanding how to administer CD19 CAR T cells in clinical practice. Although much remains to be learned, pioneering clinical trials have led to foundational insights about the clinical translation of this novel therapy. Here, we review the "lessons learned" from the pre-clinical and human experience with CAR T cell therapy. Stem Cells 2018;36:36-44.

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

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

KEY POINTS

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

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

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

ZGDHu-1 promotes apoptosis of mantle cell lymphoma cells

Mantle cell lymphoma (MCL) is a well-defined aggressive Non-Hodgkin-lymphoma with short survival rates and remains incurable to date. Previously, we demonstrated the antitumor activity of ZGDHu-1(N, N'-di-(m-methylphenyi)-3, 6-dimethyl-1, 4-dihydro-1, 2, 4, 5-tetrazine-1, 4-dicarboamide) in chronic lymphocytic leukemia. In this study, ZGDHu-1 shows potent anti-lymphoma activity in MCL cells. ZGDHu-1 significantly induces cell cycle G2/M phase arrest and apoptosis in MCL cells. ZGDHu-1 reduces the protein levels of Mcl-1, Bcl-XL and cyclin D1. Importantly, ZGDHu-1 inhibits TNFα-induced IkBa phosphorylation, p65 nuclear translocation and NF-kB downstream target gene expression in MCL cells. MCL samples expressing high levels of Bcl-2 and high Bcl-2/Bax ratios tend to be less effective to ZGDHu-1. Together, these results suggest that ZGDHu-1 could inhibit the NF-kB signaling pathway partly, which may lead to the suppression of cell proliferation and the induction of apoptosis in MCL cells. Thus, our studies provide evidence of the potential of ZGDHu-1 in treating mantle cell lymphoma.

Treatment of the elderly patient with mantle cell lymphoma

Treatment options for mantle cell lymphomas have expanded considerably over recent years, offering hematologists solutions for older patients with an appropriate risk-to-benefit ratio. Indeed, unfit older patients are exposed to a higher risk of toxicity with a standard treatment. Although new treatments have generally good safety profiles, they may lead to unexpected consequences in unfit older patients. Involving geriatricians and a comprehensive geriatric assessment in patient care could help hematologists address these vulnerabilities. The geriatric evaluation process is time-consuming but can be simplified, and its potential to help hematologists foresee unexpected consequences of treatment has now been demonstrated.

Histone deacetylase inhibitors enhance CD1d-dependent NKT cell responses to lymphoma

Histone deacetylases (HDACs) are a family of enzymes that influence expression of genes implicated in tumor initiation, progression, and anti-tumor responses. In addition to their canonical role in deacetylation of histones, HDACs regulate many non-canonical targets, such as Signal Transducer and Activator of Transcription 3 (STAT3). We hypothesize that tumors use epigenetic mechanisms to dysregulate CD1d-mediated antigen presentation, thereby impairing the ability of natural killer T (NKT) cells to recognize and destroy malignant cells. In this study, we pre-treated CD1d-expressing tumor cells with HDAC inhibitors (HDACi) and assessed CD1d-dependent NKT cell responses to mantle cell lymphoma (MCL). Pre-treatment with Trichostatin-A, a pan-HDACi, rapidly enhanced both CD1d- and MHC class II-mediated antigen presentation. Similarly, treatment of MCL cells with other HDACi resulted in enhanced CD1d-dependent NKT cell responses. The observed changes are due, at least in part, to an increase in both CD1D mRNA and CD1d cell surface expression. Mechanistically, we found that HDAC2 binds to the CD1D promoter. Knockdown of HDAC2 in tumor cells resulted in a significant increase in CD1d-mediated antigen presentation. In addition, treatment with HDACi inhibited STAT3 and STAT3-regulated inflammatory cytokine secretion by MCL cells. We demonstrated that MCL-secreted IL-10 inhibits CD1d-mediated antigen presentation and pre-treatment with TSA abrogates secretion of IL-10 by MCL. Taken together, our studies demonstrate the efficacy of HDACi in restoring anti-tumor responses to MCL through both cell-intrinsic and cell-extrinsic mechanisms and strongly implicate a role for HDACi in enhancing immune responses to cancer.

Lenalidomide-bendamustine-rituximab in patients older than 65 years with untreated mantle cell lymphoma

For elderly patients with mantle cell lymphoma (MCL), there is no defined standard therapy. In this multicenter, open-label phase 1/2 trial, we evaluated the addition of lenalidomide (LEN) to rituximab-bendamustine (R-B) as first-line treatment for elderly patients with MCL. Patients >65 years with untreated MCL, stages II-IV were eligible for inclusion. Primary end points were maximally tolerable dose (MTD) of LEN and progression-free survival (PFS). Patients received 6 cycles every four weeks of L-B-R (L D1-14, B 90 mg/m² IV, days 1-2 and R 375 mg/m² IV, day 1) followed by single LEN (days 1-21, every four weeks, cycles 7-13). Fifty-one patients (median age 71 years) were enrolled from 2009 to 2013. In phase 1, the MTD of LEN was defined as 10 mg in cycles 2 through 6, and omitted in cycle 1. After 6 cycles, the complete remission rate (CRR) was 64%, and 36% were MRD negative. At a median follow-up time of 31 months, median PFS was 42 months and 3-year overall survival was 73%. Infection was the most common nonhematologic grade 3 to 5 event and occurred in 21 (42%) patients. Opportunistic infections occurred in 3 patients: 2 Pneumocystis carinii pneumonia and 1 cytomegalovirus retinitis. Second primary malignancies (SPM) were observed in 8 patients (16%). LEN could safely be combined with R-B when added from the second cycle in patients with MCL, and was associated with a high rate of CR and molecular remission. However, we observed a high degree of severe infections and an unexpected high number of SPMs, which may limit its use. This trial is registered at www.Clinicaltrials.gov as #NCT00963534.

Pretransplantation Minimal Residual Disease Predicts Survival in Patients with Mantle Cell Lymphoma Undergoing Autologous Stem Cell Transplantation in Complete Remission

Autologous stem cell transplantation (ASCT) is standard therapy for mantle cell lymphoma (MCL) in remission after induction chemotherapy, with the best results for patients in complete remission (CR). We hypothesized that evaluation of minimal residual disease (MRD) before ASCT could further stratify outcomes for these patients. Patients with MCL who underwent ASCT in clinical CR between 1996 and 2011 with pretransplantation MRD testing were eligible. Presence of a clonal IgH rearrangement, t(11; 14) by PCR or positive flow cytometry from blood or bone marrow, was considered positive. An adjusted proportional hazards model for associations with progression-free (PFS) and overall survival (OS) was performed. Of 75 MCL patients in CR, 8 (11%) were MRD positive. MRD positivity was associated with shorter OS and PFS. The median OS for MRD-negative patients was not reached, with 82% survival at 5 years, whereas for the MRD-positive patients, median OS was 3.01 years (hazard ratio [HR], 4.04; P = .009), with a median follow-up of 5.1 years. The median PFS for MRD-negative patients was not reached with 75% PFS at 5 years, whereas for MRD-positive patients, it was 2.38 years (HR, 3.69; P = .002). MRD positivity is independently associated with poor outcomes after ASCT for MCL patients in CR.

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

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

[Ibrutinib prescription in B-cell lymphoid neoplasms]

Ibrutinib is a new-targeted therapy that irreversibly and specifically inhibits the Bruton's Tyrosine Kinase (BTK), a key component of the signaling pathways of B cells. The results are very encouraging as monotherapy in the treatment of chronic lymphocytic leukemia, mantle cell lymphoma, and Waldenström's macroglobulinemia. Following the results of recent studies, ibrutinib is now available in France for these three diseases.

Ibrutinib in combination with rituximab in relapsed or refractory mantle cell lymphoma: a single-centre, open-label, phase 2 trial

BACKGROUND

Ibrutinib is approved in the EU, USA, and other countries for patients with mantle cell lymphoma who received one previous therapy. In a previous phase 2 study with single-agent ibrutinib, the proportion of patients who achieved an objective response was 68%; 38 (34%) of 111 patients had transient lymphocytosis. We hypothesised that adding rituximab could target mantle cell lymphoma cells associated with redistribution lymphocytosis, leading to more potent antitumour activity.

METHODS

Patients with a confirmed mantle cell lymphoma diagnosis (based on CD20-positive and cyclin D1-positive cells in tissue biopsy specimens), no upper limit on the number of previous treatments received, and an Eastern Cooperative Oncology Group performance status score of 2 or less were enrolled in this single-centre, open-label, phase 2 study. Patients received continuous oral ibrutinib (560 mg) daily until progressive disease or unacceptable toxic effects. Rituximab 375 mg/m(2) was given intravenously once per week for 4 weeks during cycle 1, then on day 1 of cycles 3-8, and thereafter once every other cycle up to 2 years. The primary endpoint was the proportion of patients who achieved an objective response in the intention-to-treat population and safety assessed in the as-treated population. The study is registered with ClinicalTrials.gov, number NCT01880567, and is still ongoing, but no longer accruing patients.

FINDINGS

Between July 15, 2013, and June 30, 2014, 50 patients were enrolled. Median age was 67 years (range 45-86), and the median number of previous regimens was three (range 1-9). At a median follow-up of 16·5 months (IQR 12·09-19·28), 44 (88%, 95% CI 75·7-95·5) patients achieved an objective response, with 22 (44%, 30·0-58·7) patients achieving a complete response, and 22 (44%, 30·0-58·7) a partial response. The only grade 3 adverse event in >=10% of patients was atrial fibrillation, which was noted in six (12%) patients. Grade 4 diarrhoea and neutropenia occurred in one patient each. Adverse events led to discontinuation of therapy in five (10%) patients (atrial fibrillation in three [6%] patients, liver infection in one [2%], and bleeding in one [2%]). Two patients died while on-study from cardiac arrest and septic shock; the latter was deemed possibly related to treatment.

INTERPRETATION

Ibrutinib combined with rituximab is active and well tolerated in patients with relapsed or refractory mantle cell lymphoma. Our results provide preliminary evidence for the activity of this combination in clinical practice. A phase 3 trial is warranted for more definitive data.

FUNDING

Pharmacyclics LLC, an AbbVie Company.

Bortezomib and fenretinide induce synergistic cytotoxicity in mantle cell lymphoma through apoptosis, cell-cycle dysregulation, and IκBα kinase downregulation

Mantle cell lymphoma (MCL) remains incurable for most patients, and proteasome inhibitors like bortezomib induce responses in a minority of patients with relapsed disease. Fenretinide is a retinoid that has shown preclinical activity in B-cell lymphomas. We hypothesized that these agents could yield augmented antitumor activity. MCL lines (Granta-519, Jeko-1, and Rec-1) were treated with escalating concentrations of bortezomib and fenretinide singly and in combination. Cytotoxicity was assessed using the MTT assay. Flow cytometric methods were used to assess apoptosis and necrosis, with annexin V-FITC/propidium iodide staining, and G1 and G2 cell-cycle changes were assessed by DAPI staining. Changes in cyclin D1, cyclin B, IκBα, and IKKα expressions were quantified by western blotting. Cytotoxicity was mediated through apoptosis; both agents showed observed versus expected cytotoxicities of 92.2 versus 55.1% in Granta-519, of 87.6 versus 36.3% in Jeko-1, and of 63.2 versus 29.8% in Rec-1. Isobolographic analysis confirmed synergy in Jeko-1 and Rec-1 cell lines. Bortezomib induced G2-phase arrest, with a 1.7-fold increase compared with control, and fenretinide resulted in G1-phase arrest, with an increase of 1.3-fold compared with control. In the combination, G2-phase arrest predominated, with a 1.4-fold increase compared with control, and there was reduced expression of cyclin D1 to 24%, cyclin B to 52 and 64%, cyclin D3 to 25 and 43%, IκBα to 23 and 46%, and IκBα kinase to 34 and 44%. Bortezomib and fenretinide exhibit synergistic cytotoxicity against MCL cell lines. This activity is mediated by IκBα kinase modulation, decreased cyclin expression, cell cycle dysregulation, and apoptotic cell death.

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

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

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.

Allogeneic Hematopoietic Stem Cell Transplantation in Mantle Cell Lymphoma: A Retrospective Analysis of 7 Patients

Mantle cell lymphoma (MCL) is a B cell non-Hodgkin's lymphoma characterized by a poor prognosis. Many different therapeutic approaches including intensive chemotherapy as well as new targeted therapies are established. However, overall survival remains unsatisfying. As the sole curative option, allogeneic hematopoietic stem cell transplantation (HSCT) has been described, but only a limited number of patients qualify for this procedure. We have retrospectively analyzed 7 patients with stage IV MCL undergoing allogeneic HSCT at our institution. A myeloablative regimen was used in 1 patient, while the other 6 patients received reduced-intensity conditioning. Four patients had an HLA-identical sibling, and the remaining 3 patients had an HLA-identical unrelated donor. One patient developed acute graft-versus-host disease (skin, grade III; intestine, grade II). Two patients died from transplant-related causes, 3 patients died due to progressive disease and the remaining 2 patients are still in complete remission 147 and 8 months after transplantation. Allogeneic HSCT offers a therapeutic treatment option for selected patients in a relapsed/refractory setting. The incorporation of novel agents has improved the outcome of patients with MCL. Thus, the role and optimal time point of allogeneic HSCT should be reevaluated in randomized trials.