DLBCL: Who is high risk and how should treatment be optimized?

Diffuse large B-cell lymphoma (DLBCL) not otherwise specified is the most common subtype of large B-cell lymphoma group, with differences in prognosis, reflecting heterogeneity in pathological, molecular, and clinical features. Current treatment standard is based on multiagent chemotherapy including anthracycline and monoclonal antiCD20 antibody, which leads to cure of 60% patients. Recent years have brought new insights to the lymphoma biology and helped to refine risk groups. Results of these studies inspired design of new clinical trials with targeted therapies and response-adapted strategies and allowed to identify groups of patients potentially benefiting from new agents. This review will summarize recent progress in identifying high-risk DLBCL patients with employment of clinical and biological prognostic factors assessed at diagnosis and during treatment in the front line setting It will also discuss new treatment strategies with the application of targeted agents and immunotherapy, including response-adapted strategies.

Safety and efficacy of induction immunochemotherapy with rituximab, methotrexate, ifosfamide, and vincristine (R-MIV) in patients with primary CNS lymphoma including recent COVID-19 pandemic experience.

Clinical data on primary central nervous system (CNS) lymphoma (PCNSL) patients is mostly generated from prospective studies, and many frail real-world patients are not included. Recently,the diagnosis and treatment of PCNSL patients was confounded by the COVID-19 pandemic. In particular, treatment with high-dose cytarabine was linked to increased risk of pneumonia and virus persistence. We report on outcome of the induction regimen R-MIV (rituximab, methotrexate, ifosfamide, and vincristine) involving intensive administration of high-dose methotrexate (3.5 g/m2 ) with ifosfamide, every 2 weeks and rituximab once per week for six doses. The median age and performance status (PS) for 64 patients was 58 years and 2 (PS 3; 22%) respectively. The overall response rate by magnetic resonance imaging/computed tomography (MRI/CT) was 73% (n = 46/63), with an additional 17.5% (n = 11/63) patients without measurable disease at baseline. Grade 3-4 haematological toxicity was low for R-MIV (neutropenia: 25% and thrombocytopenia: 1%). Three patients (4.7%) died from treatment-related toxicity. Co-existence of SARS-CoV-2 infection with cytomegalovirus reactivation and the varicella-zoster virus in two patients was fatal. Fifty patients (78%) were eligible for consolidation. Median progression-free and overall survival were not reached (median follow-up: 44 months). In conclusion, the R-MIV regimen is feasible in routine practice, effective and safe, even during the COVID-19 pandemic.

High efficacy of intensive immunochemotherapy for primary mediastinal B-cell lymphoma with prolonged follow up.

Primary mediastinal B-cell lymphoma (PMBL) is currently curable in 85-95% of patients. Treatment regimens frequently used include RCHOP ± radiotherapy, DAEPOCH-R, or occasionally more intensive protocols. Here we present results of treatment of 124 patients with PMBL over a period between 2004 and 2017 with the use of a protocol designed for aggressive B-cell lymphoma GMALL/B-ALL/NHL2002 including 6 cycles of alternating immunochemotherapy with intermediate-dose methotrexate in each cycle, and reduced total doxorubicin dose (100 mg/m2 for whole treatment). Majority of patients (77%) received consolidative radiotherapy. A median (range) age of patients was 30 (18-59) years, and 60% were female. With a median (range) follow up of 9 (1-17) years, 5-year overall survival (OS) and 5-year progression free survival (PFS) were 94% and 92%, respectively. Positron emission tomography-computed tomography (PET-CT) results at the end of chemotherapy were predictive for outcome: OS and PFS at 5 year were 96% and 94% in PET-CT negative patients, respectively, and 70% and 70% in PET-CT-positive patients (p = 0.004 for OS, p = 0.01 for PFS). Eight (6%) patients had recurrent/refractory disease, however, no central nervous system (CNS) relapse was observed. Acute toxicity included pancytopenia grade 3/4, neutropenic fever, and treatment related mortality rate of 0.8%. Second malignancies and late cardiotoxicity occurred in 2.4% and 2.4% of patients, respectively. Intensive alternating immunochemotherapy protocol GMALL/B-ALL/NHL2002 is curative for more than 90% of PMBL patients and late toxicity in young patients is moderated. The attenuated dose of doxorubicin and intermediate dose of methotrexate may contribute to low incidence of late cardiotoxicity and effective CNS prophylaxis.

Ofatumumab with iphosphamide, etoposide and cytarabine for patients with transplantation-ineligible relapsed and refractory diffuse large B-cell lymphoma.

The efficacy of salvage treatment of diffuse large B-cell lymphoma (DLBCL) patients who relapse or progress (rrDLBCL) after initial therapy is limited. Efficacy and safety of ofatumumab with iphosphamide, etoposide and cytarabine (O-IVAC) was evaluated in a single-arm study. Dosing was modified for elderly patients. Patients received up to six cycles of treatment. The primary end-point was the overall response rate (ORR). Patients were evaluated every two cycles and then six and 12 months after treatment. Other end-points included progression-free survival (PFS), event-free survival (EFS), overall survival (OS) and safety. Seventy-seven patients received salvage treatment with O-IVAC. The average age was 56.8 years; 39% had an Eastern Cooperative Oncology Group (ECOG) performance status of at least 3; 78% had disease of Ann Arbor stage 3 or 4; 58% received one or more prior salvage therapies. The ORR for O-IVAC was 54.5%. The median duration of study follow-up was 70 months. The median PFS and EFS were 16.3 months each. The median OS was 22.7 months. Age, ECOG performance status and the number of prior therapy lines were independent predictors of survival. Treatment-related mortality was 15.5%. O-IVAC showed a high response rate in a difficult-to-treat population and is an attractive treatment to bridge to potentially curative therapies.

Analysis of data collected in the European Society for Blood and Marrow Transplantation (EBMT) Registry on a cohort of lymphoma patients receiving plerixafor.

Plerixafor + granulocyte-colony stimulating factor (G-CSF) is administered to patients with lymphoma who are poor mobilizers of hematopoietic stem cells (HSCs) in Europe. This international, multicenter, non-interventional registry study (NCT01362972) evaluated long-term follow-up of patients with lymphoma who received plerixafor for HSC mobilization versus other mobilization methods. Propensity score matching was conducted to balance baseline characteristics between comparison groups. The following mobilization regimens were compared: G-CSF + plerixafor (G + P) versus G-CSF alone; G + P versus G-CSF + chemotherapy (G + C); and G-CSF + plerixafor + chemotherapy (G + P + C) versus G + C. The primary outcomes were progression-free survival (PFS), overall survival (OS), and cumulative incidence of relapse (CIR). Overall, 313/3749 (8.3%) eligible patients were mobilized with plerixafor-containing regimens. After propensity score matching, 70 versus 36 patients were matched in the G + P versus G-CSF alone cohort, 124 versus 124 in the G + P versus G + C cohort, and 130 versus 130 in the G + P + C versus G + C cohort. For both PFS and OS, the upper bound of confidence interval for the hazard ratio was >1.3 for all comparisons, implying that non-inferiority was not demonstrated. No major differences in PFS, OS, and CIR were observed between the plerixafor and comparison groups.

First-line R-CVP versus R-CHOP induction immunochemotherapy for indolent lymphoma with rituximab maintenance. A multicentre, phase III randomized study by the Polish Lymphoma Research Group PLRG4.

R-CVP (cyclophosphamide, vincristine, prednisone) and R-CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone + rituximab) are immunochemotherapy regimens frequently used for remission induction of indolent non-Hodgkin lymphomas (iNHLs). Rituximab maintenance (RM) significantly improves progression-free survival (PFS) in patients with complete/partial remission (CR/PR). Here we report the final results of a randomized study comparing R-CVP to R-CHOP both followed by RM. Untreated patients in need of systemic therapy with symptomatic and progressive iNHLs including follicular (FL) and marginal zone lymphoma (MZL), mucosa-associated lymphoid tissue (MALT), small lymphocytic (SLL), and lymphoplasmacytic (LPL) lymphoma were eligible. Patients were randomized to receive R-CVP or R-CHOP for eight cycles or until complete response (CR). All patients with CR/PR (partial response) received RM 375 mg/m2 q 2 months for 12 cycles. Primary endpoint was event-free survival (EFS). Two-hundred and fifty patients [FL 42%, MZL/MALT 38%, LPL/ Waldenström Macroglobulinaemia (WM) 11%, SLL 9%] were enrolled and randomized (R-CHOP: 127, R-CVP: 123). Median age was 56 years (21-85), 44% were male, 90% were in stage III-IV, 43% of FL patients had a Follicular Lymphoma International Prognostic Index (FLIPI) score ≥3, and 33·4% of all patients had an IPI score ≥3. At the end of induction treatment, the CR/PR rate was 43·6/50·9% and 36·3/60·8% in the R-CHOP and R-CVP groups (P = 0·218) respectively. After a median follow-up of 67, 66, and 70 months, five-year EFS was 61% vs. 56% (not significant), progression-free survival (PFS) was 71% vs. 69% (not significant) and overall survival (OS) was 84% vs. 89% in the R-CHOP vs. the R-CVP arm respectively. Grade III/IV adverse events (65 vs. 22) occurred in 40 (33·1%) and 18 (15·3%) patients, P = 0·001; neutropenia in 16 (11·6%) and 4 (3·4%) patients, P = 0·017; infection in 14 (10·7%) and 3 (2·5%) patients,; P = 0·011; and a second neoplasm in three versus seven patients., in the R-CHOP and the R-CVP groups respectively. This multicentre randomized study with >five-year follow-up shows similar outcome in patients with indolent lymphoma in need of systemic therapy treated with R-CVP or R-CHOP immunochemotherapy and rituximab maintenance in both arms. The minor toxicity of the R-CVP regimen makes it a reasonable choice for induction treatment, leaving other active agents like doxorubicin or bendamustin for second-line therapy.

Inhibitors of SRC kinases impair antitumor activity of anti-CD20 monoclonal antibodies.

Clinical trials with SRC family kinases (SFKs) inhibitors used alone or in a combination with anti-CD20 monoclonal antibodies (mAbs) are currently underway in the treatment of B-cell tumors. However, molecular interactions between these therapeutics have not been studied so far. A transcriptional profiling of tumor cells incubated with SFKs inhibitors revealed strong downregulation of MS4A1 gene encoding CD20 antigen. In a panel of primary and established B-cell tumors we observed that SFKs inhibitors strongly affect CD20 expression at the transcriptional level, leading to inhibition of anti-CD20 mAbs binding and increased resistance of tumor cells to complement-dependent cytotoxicity. Activation of the AKT signaling pathway significantly protected cells from dasatinib-triggered CD20 downregulation. Additionally, SFKs inhibitors suppressed antibody-dependent cell-mediated cytotoxicity by direct inhibition of natural killer cells. Abrogation of antitumor activity of rituximab was also observed in vivo in a mouse model. Noteworthy, the effects of SFKs inhibitors on NK cell function are largely reversible. The results of our studies indicate that development of optimal combinations of novel treatment modalities with anti-CD20 mAbs should be preceded by detailed preclinical evaluation of their effects on target cells.

Primary mediastinal large B-cell lymphoma.

Primary mediastinal B-cell lymphoma (PMBCL) is a relatively rare lymphoma subtype affecting mainly young adults. Its molecular signature and clinical features resemble classical Hodgkin lymphoma. The optimal chemotherapy for this lymphoma subtype has not been established. The addition of rituximab to anthracycline based chemotherapy improved response rates and survival. Many centers use R-CHOP as standard treatment, but the role of the intensified regimens and consolidation radiotherapy has to be clarified. Recent data coming from retrospective analyses and an ongoing prospective study addressing the problem of consolidation radiotherapy will help to better identify risk groups and apply risk-adapted and effective treatment strategies. The latest research has helped to understand molecular mechanisms of PMBCL pathogenesis and indicated targets of directed therapy for the future.

Hematopoietic stem cell mobilization with the reversible CXCR4 receptor inhibitor plerixafor (AMD3100)-Polish compassionate use experience.

Recent developments in the field of targeted therapy have led to the discovery of a new drug, plerixafor, that is a specific inhibitor of the CXCR4 receptor. Plerixafor acts in concert with granulocyte colony-stimulating factor (G-CSF) to increase the number of stem cells circulating in the peripheral blood (PB). Therefore, it has been applied in the field of hematopoietic stem cell mobilization. We analyzed retrospectively data regarding stem cell mobilization with plerixafor in a cohort of 61 patients suffering from multiple myeloma (N = 23), non-Hodgkin's lymphoma (N = 20), or Hodgkin's lymphoma (N = 18). At least one previous mobilization attempt had failed in 83.6% of these patients, whereas 16.4% were predicted to be poor mobilizers. The median number of CD34+ cells in the PB after the first administration of plerixafor was 22/µL (range of 0-121). In total, 85.2% of the patients proceeded to cell collection, and a median of two (range of 0-4) aphereses were performed. A minimum of 2.0 × 10(6) CD34+ cells per kilogram of the patient's body weight (cells/kg b.w.) was collected from 65.6% of patients, and the median number of cells collected was 2.67 × 10(6) CD34+ cells/kg b.w. (0-8.0). Of the patients, 55.7% had already undergone autologous stem cell transplantation, and the median time to neutrophil and platelet reconstitution was 12 and 14 days, respectively. Cases of late graft failure were not observed. We identified the diagnosis of non-Hodgkin's lymphoma and previous radiotherapy as independent factors that contributed to failure of mobilization. The current report demonstrates the satisfactory efficacy of plerixafor plus G-CSF for stem cell mobilization in heavily pre-treated poor or predicted poor mobilizers.

Cardiotoxicity of the anticancer therapeutic agent bortezomib.

Recent case reports provided alarming signals that treatment with bortezomib might be associated with cardiac events. In all reported cases, patients experiencing cardiac problems were previously or concomitantly treated with other chemotherapeutics including cardiotoxic anthracyclines. Therefore, it is difficult to distinguish which components of the therapeutic regimens contribute to cardiotoxicity. Here, we addressed the influence of bortezomib on cardiac function in rats that were not treated with other drugs. Rats were treated with bortezomib at a dose of 0.2 mg/kg thrice weekly. Echocardiography, histopathology, and electron microscopy were used to evaluate cardiac function and structural changes. Respiration of the rat heart mitochondria was measured polarographically. Cell culture experiments were used to determine the influence of bortezomib on cardiomyocyte survival, contractility, Ca(2+) fluxes, induction of endoplasmic reticulum stress, and autophagy. Our findings indicate that bortezomib treatment leads to left ventricular contractile dysfunction manifested by a significant drop in left ventricle ejection fraction. Dramatic ultrastructural abnormalities of cardiomyocytes, especially within mitochondria, were accompanied by decreased ATP synthesis and decreased cardiomyocyte contractility. Monitoring of cardiac function in bortezomib-treated patients should be implemented to evaluate how frequently cardiotoxicity develops especially in patients with pre-existing cardiac conditions, as well as when using additional cardiotoxic drugs.

Bortezomib modulates surface CD20 in B-cell malignancies and affects rituximab-mediated complement-dependent cytotoxicity.

Unresponsiveness to rituximab treatment develops in many patients prompting elucidation of underlying molecular pathways. It was recently observed that rituximab-resistant lymphoma cells exhibit up-regulation of components of the ubiquitin-proteasome system (UPS). Therefore, we investigated in more detail the role of this system in the regulation of CD20 levels and the influence of proteasome inhibitors on rituximab-mediated complement-dependent cytotoxicity (R-CDC). We observed that incubation of Raji cells with rituximab leads to increased levels of ubiquitinated CD20. However, inhibition of the UPS was not associated with up-regulation of surface CD20 levels, although it significantly increased its ubiquitination. Short-term (24 hours) incubation of Raji cells with 10 or 20 nM bortezomib did not change surface CD20 levels, but sensitized CD20(+) lymphoma cells to R-CDC. Prolonged (48 hours) incubation with 20 nM bortezomib, or incubation with 50 nM bortezomib for 24 hours led to a significant decrease in surface CD20 levels as well as R-CDC. These effects were partly reversed by bafilomycin A1, an inhibitor of lysosomal/autophagosomal pathway of protein degradation. These studies indicate that CD20 levels are regulated by 2 proteolytic systems and that the use of proteasome inhibitors may be associated with unexpected negative influence on R-CDC.

Statins impair antitumor effects of rituximab by inducing conformational changes of CD20.

BACKGROUND: Rituximab is used in the treatment of CD20+ B cell lymphomas and other B cell lymphoproliferative disorders. Its clinical efficacy might be further improved by combinations with other drugs such as statins that inhibit cholesterol synthesis and show promising antilymphoma effects. The objective of this study was to evaluate the influence of statins on rituximab-induced killing of B cell lymphomas. METHODS AND FINDINGS: Complement-dependent cytotoxicity (CDC) was assessed by MTT and Alamar blue assays as well as trypan blue staining, and antibody-dependent cellular cytotoxicity (ADCC) was assessed by a 51Cr release assay. Statins were found to significantly decrease rituximab-mediated CDC and ADCC of B cell lymphoma cells. Incubation of B cell lymphoma cells with statins decreased CD20 immunostaining in flow cytometry studies but did not affect total cellular levels of CD20 as measured with RT-PCR and Western blotting. Similar effects are exerted by other cholesterol-depleting agents (methyl-beta-cyclodextrin and berberine), but not filipin III, indicating that the presence of plasma membrane cholesterol and not lipid rafts is required for rituximab-mediated CDC. Immunofluorescence microscopy using double staining with monoclonal antibodies (mAbs) directed against a conformational epitope and a linear cytoplasmic epitope revealed that CD20 is present in the plasma membrane in comparable amounts in control and statin-treated cells. Atomic force microscopy and limited proteolysis indicated that statins, through cholesterol depletion, induce conformational changes in CD20 that result in impaired binding of anti-CD20 mAb. An in vivo reduction of cholesterol induced by short-term treatment of five patients with hypercholesterolemia with atorvastatin resulted in reduced anti-CD20 binding to freshly isolated B cells. CONCLUSIONS: Statins were shown to interfere with both detection of CD20 and antilymphoma activity of rituximab. These studies have significant clinical implications, as impaired binding of mAbs to conformational epitopes of CD20 elicited by statins could delay diagnosis, postpone effective treatment, or impair anti-lymphoma activity of rituximab.

Augmented antitumour effects of combination therapy with TNP-470 and chemoimmunotherapy in mice.

PURPOSE: To investigate antitumour efficacy of the combination of the antiangiogenic agent TNP-470 combined with chemoimmunotherapy in different tumour models in mice MATERIALS: B6D2F1 mice and BALB/c mice were inoculated in the footpad of the right hind limb with B16F10 melanoma cells or colon adenocarcinoma cells C-26, respectively. Subsequently, they received therapy consisting of TNP-470 and/or IL-12 and tumour growth was observed. In the melanoma model this therapy regimen was combined with cisplatin in a subtherapeutic dose. The antiangiogenic action of the tested agents was evaluated using tumour-induced angiogenesis assay in vivo. In order to analyse interactions between TNP-470 (or cisplatin) and IFN-gamma on tumour cells in vitro, the following methods were used: MTT assay, Western blot analysis, and flow cytometry analysis. RESULTS: Administration of the combined therapy with TNP-470 and IL-12 resulted in augmented antitumour activity in colon-26 and B16F10 melanoma models. Addition of cisplatin further enhanced efficacy of this combined therapy in the melanoma model. We showed that antitumour activity of this combined therapy is mediated by multiple mechanisms: not only is enhancement of the antiangiogenic activity mediated by TNP-470 and IL-12 but also by the synergistic cytostatic/cytotoxic action of IL-12-induced IFN-gamma and TNP-470 or cisplatin on tumour cells. The experiments revealed that TNP-470 together with IFN-gamma leads to the increased expression of p21 protein in cancer cells, which in turn may contribute to their cytostatic/cytotoxic action in vitro. CONCLUSION: Our experiments show a successful TNP-470-based combination therapy and suggest that the enhancement of the antitumour activity could be explained by a concomitant effect on both endothelial and tumour cell compartments.