Radiotherapy in younger patients with advanced aggressive B-cell lymphoma-long-term results from the phase 3 R-MegaCHOEP trial.

The role of consolidative radiotherapy (RT) for patients with aggressive B-cell lymphoma has not been fully elucidated. The R-MegaCHOEP trial investigated the use of high-dose chemotherapy and rituximab with subsequent autologous stem cell transplantations compared to conventional immunochemotherapy (R-CHOEP) for high-risk patients up to 60 years. The study protocol included RT for patients with bulky (maximum diameter ≥7.5 cm) or extranodal disease. Two-hundred sixty-one patients were analyzed, 120 of whom underwent RT. The most frequently irradiated regions were mediastinum (n = 50) and paraaortic (n = 27). Median RT dose was 36 Gray in median fractions of 1.8 Gray. Acute toxicities were mostly mild to moderate, with only 24 and 8 grade 3 and 4 toxicities reported during RT. Patients with bulky disease who received RT showed significantly better 10-year EFS, PFS and OS (EFS: 64% vs. 35%; p < 0.001; PFS 68% vs. 47%; p = 0.003; OS: 72% vs. 59%; p = 0.011). There was no significant increase in secondary malignancies with the use of RT. RT administered for consolidation of bulky disease after immunochemotherapy improved the prognosis of young high-risk patients with aggressive B-cell lymphoma and should be considered part of first-line therapy. The trial was registered with ClinicalTrials.gov, number NCT00129090.

Molecular profiling of EBV associated diffuse large B-cell lymphoma.

Epstein-Barr virus (EBV) associated diffuse large B-cell lymphoma (DLBCL) represents a rare aggressive B-cell lymphoma subtype characterized by an adverse clinical outcome. EBV infection of lymphoma cells has been associated with different lymphoma subtypes while the precise role of EBV in lymphomagenesis and specific molecular characteristics of these lymphomas remain elusive. To further unravel the biology of EBV associated DLBCL, we present a comprehensive molecular analysis of overall 60 primary EBV positive (EBV+) DLBCLs using targeted sequencing of cancer candidate genes (CCGs) and genome-wide determination of recurrent somatic copy number alterations (SCNAs) in 46 cases, respectively. Applying the LymphGen classifier 2.0, we found that less than 20% of primary EBV + DLBCLs correspond to one of the established molecular DLBCL subtypes underscoring the unique biology of this entity. We have identified recurrent mutations activating the oncogenic JAK-STAT and NOTCH pathways as well as frequent amplifications of 9p24.1 contributing to immune escape by PD-L1 overexpression. Our findings enable further functional preclinical and clinical studies exploring the therapeutic potential of targeting these aberrations in patients with EBV + DLBCL to improve outcome.

Central nervous system relapse in younger patients with diffuse large B-cell lymphoma: a LYSA and GLA/DSHNHL analysis.

Most patients with diffuse large B-cell lymphoma (DLBCL) can be cured with immunochemotherapy such as R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone). Patients with progression or relapse in the central nervous system (CNS) face dismal outcomes. The impact of more aggressive regimens used in frontline therapy has not been systematically investigated in this context. To this end, we analyzed a large cohort of 2203 younger patients with DLBCL treated on 10 German (German Lymphoma Alliance [GLA]/The German High Grade Non-Hodgkin's Lymphoma Study Group [DSHNHL]) and French (The Lymphoma Study Association [LYSA]) prospective phase 2 and 3 trials after first-line therapy with R-CHOP, R-CHOEP (R-CHOP + etoposide), dose-escalated R-CHOEP followed by repetitive stem cell transplantation (R-MegaCHOEP), or R-ACVBP (rituximab, doxorubicin, cyclophosphamide, vindesine, bleomycine, and prednisone) followed by consolidation including multiple drugs crossing the blood-brain barrier (BBB). Patients with DLBCL with an age-adjusted International Prognostic Index (aaIPI) of 0 to 1 showed very low cumulative incidence rates of CNS relapse regardless of first-line therapy and CNS prophylaxis (3-year cumulative incidences 0%-1%). Younger high-risk patients with aaIPI of 2 to 3 had 3-year cumulative incidence rates of 1.6% and 4% after R-ACVBP plus consolidation or R-(Mega)CHO(E)P, respectively (hazard ratio 2.4; 95% confidence interval: 0.8-7.4; P = .118). Thus, for younger high-risk patients, frontline regimens incorporating agents crossing the BBB may reduce often fatal CNS relapse.

Plasmablastic lymphoma: from genetics to treatment.

Plasmablastic lymphoma (PBL) represents a rare distinct lymphoma entity with plasmablastic morphology and plasmacytic immunophenotype that is characterized by an aggressive clinical course. Standard chemotherapeutic regimens often remain insufficient to cure affected patients. Recently, comprehensive molecular analyses of large cohorts of primary PBL samples have revealed the mutational landscape as well as the pattern of copy number alterations of this rare lymphoma subtype. Identification of recurrent aberrations affecting the JAK-STAT, RAS-RAF, NOTCH, IRF4, and MYC signaling pathways drive the molecular pathogenesis of PBL and hold great potential for novel targeted therapeutic approaches.

mTOR inhibition amplifies the anti-lymphoma effect of PI3Kß/δ blockage in diffuse large B-cell lymphoma.

Diffuse large B-cell lymphoma (DLBCL) is an aggressive disease that exhibits constitutive activation of phosphoinositide 3-kinase (PI3K) driven by chronic B-cell receptor signaling or PTEN deficiency. Since pan-PI3K inhibitors cause severe side effects, we investigated the anti-lymphoma efficacy of the specific PI3Kß/δ inhibitor AZD8186. We identified a subset of DLBCL models within activated B-cell-like (ABC) and germinal center B-cell-like (GCB) DLBCL that were sensitive to AZD8186 treatment. On the molecular level, PI3Kß/δ inhibition decreased the pro-survival NF-κB and AP-1 activity or led to downregulation of the oncogenic transcription factor MYC. In AZD8186-resistant models, we detected a feedback activation of the PI3K/AKT/mTOR pathway following PI3Kß/δ inhibition, which limited AZD8186 efficacy. The combined treatment with AZD8186 and the mTOR inhibitor AZD2014 overcame resistance to PI3Kß/δ inhibition and completely prevented outgrowth of lymphoma cells in vivo in cell line- and patient-derived xenograft mouse models. Collectively, our study reveals that subsets of DLBCLs are addicted to PI3Kß/δ signaling and thus identifies a previously unappreciated role of the PI3Kß isoform in DLBCL survival. Furthermore, our data demonstrate that combined targeting of PI3Kß/δ and mTOR is effective in all major DLBCL subtypes supporting the evaluation of this strategy in a clinical trial setting.

Current options and future perspectives in the treatment of patients with relapsed/refractory diffuse large B-cell lymphoma.

Diffuse large B-cell lymphoma (DLBCL) represents the most common subtype of aggressive lymphoma. Depending on individual risk factors, roughly 60-65% of patients can be cured by chemoimmunotherapy with rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP). However, patients with primary refractory disease or relapse (R/R) after an initial response are still characterized by poor outcome. Until now, transplant-eligible R/R DLBCL patients are treated with intensive salvage regimens followed by high-dose chemotherapy and autologous stem cell transplantation (ASCT) which, however, only cures a limited number of patients. It is most likely that in patients with early relapse after chemoimmunotherapy, chimeric antigen receptor (CAR) T-cells will replace high-dose chemotherapy and ASCT. So far, transplant-ineligible patients have mostly been treated in palliative intent. Recently, a plethora of novel agents comprising new monoclonal antibodies, antibody drug conjugates (ADC), bispecific antibodies, and CAR T-cells have emerged and have significantly improved outcome of patients with R/R DLBCL. In this review, we summarize our current knowledge on the usage of novel drugs and approaches for the treatment of patients with R/R DLBCL.

A phase II trial to evaluate the combination of pixantrone and obinutuzumab for patients with relapsed aggressive lymphoma: Final results of the prospective, multicentre GOAL trial.

The prognosis of patients with relapsed diffuse large B-cell lymphoma (DLBCL) remains poor with current options. Here we prospectively evaluated the combination of pixantrone with obinutuzumab for up to six cycles for patients with relapsed or refractory DLBCL. Overall response rate (ORR) was the primary end-point. Sixty-eight patients were evaluated, median age was 75 years, median number of prior lines was three (range 1-10), 52 patients (76.5%) were diagnosed with DLBCL and 16 (23.5%) patients had transformed indolent lymphoma or follicular lymphoma (FL) IIIB. ORR was 35.3% for all and 40% for evaluable patients (16.6% complete response), median progression-free survival (PFS) and overall survival (OS) were 2.8 months and 8 months, respectively. Analysis of the cell of origin revealed a superior course for patients with non-GCB (germinal centre B-cell-like) phenotype [median OS not reached (n.r.) vs 5.2 months]. Patients with one prior line had an improved outcome over patients treated in later lines (PFS n.r. vs 2.5 months). Disease progression was the main reason for premature termination. Adverse events were mainly haematologic. The combination treatment revealed no unexpected adverse events. Most relevant non-haematologic toxicity was infection in 28% of patients. In summary, pixantrone-obinutuzumab showed clinical activity with sometimes long-term remission; however, the trial failed to meet its primary end-point.

Molecular and functional profiling identifies therapeutically targetable vulnerabilities in plasmablastic lymphoma.

Plasmablastic lymphoma (PBL) represents a rare and aggressive lymphoma subtype frequently associated with immunosuppression. Clinically, patients with PBL are characterized by poor outcome. The current understanding of the molecular pathogenesis is limited. A hallmark of PBL represents its plasmacytic differentiation with loss of B-cell markers and, in 60% of cases, its association with Epstein-Barr virus (EBV). Roughly 50% of PBLs harbor a MYC translocation. Here, we provide a comprehensive integrated genomic analysis using whole exome sequencing (WES) and genome-wide copy number determination in a large cohort of 96 primary PBL samples. We identify alterations activating the RAS-RAF, JAK-STAT, and NOTCH pathways as well as frequent high-level amplifications in MCL1 and IRF4. The functional impact of these alterations is assessed using an unbiased shRNA screen in a PBL model. These analyses identify the IRF4 and JAK-STAT pathways as promising molecular targets to improve outcome of PBL patients.

Rituximab plus high-dose chemotherapy (MegaCHOEP) or conventional chemotherapy (CHOEP-14) in young, high-risk patients with aggressive B-cell lymphoma: 10-year follow-up of a randomised, open-label, phase 3 trial.

BACKGROUND: R-MegaCHOEP was the first phase 3 study comparing high-dose chemotherapy plus rituximab followed by autologous haematopoietic stem-cell transplantation (HSCT) with conventional chemotherapy plus rituximab in first-line therapy for patients aged 60 years or younger with high-risk aggressive B-cell lymphoma. Little is known about the long-term outcomes of these patients. We aimed to evaluate the long-term efficacy and safety of conventional chemotherapy versus high-dose chemotherapy after 10 years of follow-up in the R-MegaCHOEP trial. METHODS: In this open-label, randomised, phase 3 trial done across 61 centres in Germany, patients aged 18-60 years with newly diagnosed, high-risk (age-adjusted International Prognostic Index [IPI] 2 or 3) aggressive B-cell lymphoma were randomly assigned (1:1, using Pocock minimisation) to eight cycles of conventional chemotherapy (cyclosphosphamide, doxorubicin, vincristine, etoposide, and prednisolone) plus rituximab (R-CHOEP-14) or four cycles of high-dose chemotherapy plus rituximab followed by autologous HSCT (R-MegaCHOEP). The trial was unmasked. Patients were stratified by age-adjusted IPI factors, presence of bulky disease (tumour mass ≥7·5 cm diameter), and treatment centre. The primary endpoint was event-free survival, analysed here 10 years after randomisation. 10-year overall survival, progression-free survival, conditional survival, relapse patterns, secondary malignancies, and molecular characteristics were also analysed. All analyses were done on the intention-to-treat population. This trial is registered with ClinicalTrials.gov, NCT00129090. FINDINGS: Between March 3, 2003, and April 7, 2009, 275 patients were randomly assigned to R-CHOEP-14 (n=136) or R-MegaCHOEP (n=139). 130 patients in the R-CHOEP-14 group and 132 patients in the R-MegaCHOEP group were included in the intention-to-treat population. After a median follow-up of 9·3 years (IQR 5·1-11·1), 10-year event-free survival was 51% (95% CI 42-61) in the R-MegaCHOEP group and 57% (47-67) in the R-CHOEP-14 group (adjusted hazard ratio [HR] 1·3 [95% CI 0·9-1·8], p=0·23). 10-year progression-free survival was 59% (50-68) in the R-MegaCHOEP group and 60% (51-70) in the R-CHOEP-14 group (adjusted HR 1·1 [0·7-1·7], p=0·64). 10-year overall survival was 66% (57-76) in the R-MegaCHOEP group and 72% (63-81) in the R-CHOEP-14 group (adjusted HR 1·3 [0·8-2·1], p=0·26). Relapse occurred in 30 (16% [95% CI 11-22]) of 190 patients who had complete remission or unconfirmed complete remission; 17 (17%) of 100 patients in the R-CHOEP-14 group and 13 (14%) of 90 patients in the R-MegaCHOEP group. Seven (23%) of 30 patients had low-grade histology at relapse and had better outcomes compared with patients who relapsed with aggressive histologies. Lymphoma affected the CNS in 18 (28%) of 64 patients with treatment failure. 22 secondary malignancies were reported in the intention-to-treat population; in 12 (9%) of 127 patients in the R-CHOEP-14 group and ten (8%) of 126 patients in the R-MegaCHOEP group. INTERPRETATION: Event-free survival and overall survival were similar between groups after 10 years of follow-up; outcomes were not improved in the R-MegaCHOEP group by high-dose chemotherapy and autologous HSCT. Patients who relapsed with aggressive histology showed a high incidence of CNS involvement and poor prognosis. For these patients, novel therapies are greatly warranted. FUNDING: Deutsche Krebshilfe (German Cancer Aid).

Cytokeratin expression in plasmablastic lymphoma - a possible diagnostic pitfall in the routine work-up of tumours.

AIMS: Plasmablastic lymphoma (PBL) is a rare aggressive B-cell lymphoma that frequently arises at extranodal sites in the setting of immunosuppression. The diagnosis of PBL is complex, owing to a frequent solid or cohesive growth pattern, and an often unusual immunophenotype. Several case reports have described cytokeratin (CK) expression in PBL, introducing a diagnostic pitfall. The aim of this study was to determine the frequency of CK expression in PBL in the largest series available to date. METHODS AND RESULTS: By using immunohistochemistry in a cohort of 72 PBLs, we identified CK8/18 positivity in 11 of 72 cases (15%) and AE1/3 positivity in six of 65 cases (9%), clearly contrasting with a control series of non-PBL aggressive B-cell lymphomas (one of 96 diffuse large B-cell lymphomas), as well as with data in the literature describing only occasional CK expression in haematological neoplasms. CONCLUSIONS: Our data indicate CK expression in a substantial number (15%) of PBLs. In view of the particular morphological features of PBL and its frequent negativity for the common leukocyte antigen and B-cell markers, this feature represents a pitfall in the routine diagnostic work-up of PBL, and requires more extensive immunohistochemical and molecular characterisation of cases entering the differential diagnosis.

MMP3 activity rather than cortical stiffness determines NHE1-dependent invasiveness of melanoma cells.

BACKGROUND: Both cell adhesion and matrix metalloproteinase (MMP) activity depend on pH at the cell surface. By regulating extracellular juxtamembrane pH, the Na+/H+ exchanger NHE1 plays a significant part in human melanoma (MV3) cell migration and invasion. Because NHE1, besides its pH-regulatory transport function, also serves as a structural element tying the cortical actin cytoskeleton to the plasma membrane, we investigated whether NHE1 affects cortical stiffness of MV3 cells, and how this makes an impact on their invasiveness. METHODS: NHE1 overexpressing MV3 cells were compared to the corresponding mock-transfected control cells. NHE1 expression was verified by Western blotting, cariporide (HOE642) was used to inhibit NHE1 activity, cell stiffness was determined by atomic force microscopy, and F-actin was visualized by phalloidin-staining. Migration on, and invasion of, native and glutaraldehyde-fixed collagen I substrates were analyzed using time-lapse video microscopy and Boyden-chamber assays, respectively. MMP secretion and activity were detected by Western blot and zymography, respectively. MMP activity was inhibited with NNGH. RESULTS: The cortical, but not the bulk stiffness, was significantly higher in NHE1 overexpressing cells. This increase in cortical stiffness was accompanied by a reorganization of the cortical cytoskeleton, i.e. a condensation of F-actin underneath and along the plasma membrane. However, it was not affected by NHE1 inhibition. Nevertheless, actin dynamics is required for cell invasion as demonstrated with the application of cytochalasin D. NHE1 overexpression was associated with an elevated MMP3 secretion and an increase in the invasion of a native matrix. This increase in invasiveness could be antagonized by the MMP inhibitor NNGH. Transmigration through a glutaraldehyde-fixed, indigestible substrate was not affected by NHE1 overexpression. CONCLUSION: NHE1, as a structural element and independently of its transport activity, contributes to the organization of the cortical F-actin meshwork and thus impacts cortical stiffness. Since NHE1 overexpression stimulates MMP3 secretion but does not change transmigration through a fixed substrate, MV3 cell invasion of a native substrate depends on MMP activity rather than on a modifiable cortical stiffness.

Novel insights into the pathogenesis of molecular subtypes of diffuse large B-cell lymphoma and their clinical implications.

Introduction: Diffuse large B-cell lymphoma (DLBCL) represents a heterogeneous diagnostic category consisting of different molecular subtypes relying in their biology on distinct signaling pathways.Areas covered: This article provides an overview of the molecular understanding in DLBCL and highlights potential clinical implications reviewing relevant publications and clinical trials from PubMed and clinicaltrials.gov until August 2019.Expert opinion: Based on gene expression profiling, DLBCL can be divided in two broad subtypes, the activated B-cell-like (ABC) and germinal centre derived (GCB) DLBCL. Recent comprehensive genomic analyses revealed reproducible molecular clusters within the ABC/GCB classification and suggest a more profound molecular characterization to stratify patients within clinical trials. During the last couple of years, a multitude of novel targeted therapies has been developed, but so far without improving our current therapeutic standard of immunochemotherapy. Next to the limitation of toxic side effects and a more precise selection of patients, one of the greatest challenges will be to provide molecular characterization in a more time efficient way to enable a specific and individual treatment strategy.

Functional interdependence of NHE1 and merlin in human melanoma cells.

Upregulation of the Na(+)/H(+) exchanger isoform 1 (NHE1) has been correlated with tumor malignancy. In contrast, moesin-radixin-ezrin-like protein (merlin) is a tumor suppressor that protects from cancerogenesis. Merlin is highly related to the members of the ezrin, radixin, and moesin (ERM) protein family that are directly attached to and functionally linked with NHE1. In addition, merlin inhibits the MAPK cascade and the Rho-GTPases known to activate NHE1 activity. The present study investigates whether NHE1 expression and activity affect merlin or, conversely, whether merlin has an impact on NHE1 in human melanoma (MV3) cells. Indeed, features of merlin-deficient MV3 cells point to a functional link: merlin-deficient cells showed a decreased NHE1 expression and, paradoxically, an increase in NHE1 activity as measured upon cytosolic acidification (NH4Cl prepulse method). Loss of merlin also led to an elevated cell motility that could be further increased by NHE1 overexpression, whereas NHE1 overexpression alone had no effect on migration. In contrast, neither NHE1 expression nor its activity had an impact on merlin expression. These results suggest a novel tumor suppressor function of merlin in melanoma cells: the inhibition of the proto-oncogenic NHE1 activity, possibly including its downstream signaling pathways.