Targeting regulatory T cells by E7777 enhances CD8 T-cell-mediated anti-tumor activity and extends survival benefit of anti-PD-1 in solid tumor models.

Introduction: Regulatory T cell (Treg)-targeting cancer immunotherapy aims to transiently deplete Treg cells in the tumor microenvironment, without affecting effector T cells (Teff), thus both enhancing anti-tumor activity and avoiding autoimmunity. This study evaluated whether adding E7777 (a new formulation of denileukin diftitox [DD]) improved the efficacy of anti-PD-1 antibody therapy. DD is a recombinant protein containing the hydrophobic and catalytic portions of diphtheria toxin fused to full-length human IL-2. E7777 has the same amino acid sequence and brief circulatory half-life as DD, but with greater purity and potency. Methods: Subcutaneous syngeneic murine solid tumor models (colon cancer CT-26 and liver cancer H22) were used to evaluate safety, efficacy, and overall survival with E7777 and anti-PD-1 antibodies, each administered as monotherapy or in concurrent or sequential combination. In Experiment 1, treatments were compared to assess anti-tumor activity at various time points, with tumors excised and dissociated and tumor leukocytes characterized. In Experiment 2, tumor growth, response, and overall survival were characterized for 100 days following a 3-week treatment. Results: E7777 administered in combination with anti-PD-1 led to significantly increased anti-tumor activity and durable, extended overall survival compared to either treatment alone. In both tumor models, the Treg cell infiltration induced by anti-PD-1 treatment was counterbalanced by co-treatment with E7777, suggesting potential synergistic activity. Combination therapy showed the most favorable results. Treatment with E7777 was safe and well-tolerated. Discussion: Combined E7777 and anti-PD-1 therapy was well tolerated and more effective than monotherapy with either drug.

Biomarkers for Risk Stratification in Patients With Previously Untreated Follicular Lymphoma Receiving Anti-CD20-based Biological Therapy.

Follicular lymphoma (FL) is an indolent B-cell neoplasm of germinal center origin. Standard treatment regimens consist of anti-CD20 therapy with or without chemotherapy. While high response rates to initial therapy are common, patients ultimately relapse or have progressive disease. Clinical risk factors such as the Follicular Lymphoma International Prognostic Index (FLIPI) have been identified, but there is a need for prognostic and predictive biomarkers. We studied markers of lymphoma cells and tumor microenvironment by immunohistochemistry in tissue samples from patients enrolled in 1 of 4 phase 2 trials of anti-CD20-based biological therapy for previously untreated grades 1 to 2 or 3A FL. Results were correlated with progression-free survival (PFS) and PFS status at 24 months. The 4 trials included 238 patients (51.1% male, median age: 55 y) with stage III, IV, or bulky stage II disease. By FLIPI, 24.6% had low-risk, 56.8% had intermediate-risk, and 18.6% had high-risk disease. The outcome differed significantly for patients treated with lenalidomide and rituximab (CALGB 50803) compared with the other 3 trials (median: PFS not reached vs. 3.0 y, hazard ratio=3.47, 95% confidence interval: 2.11-5.72); therefore, data were stratified by clinical trial (CALGB 50803 vs. all others) and adjusted for FLIPI risk group. Among 154 patients with available tissue, interfollicular BCL6 positivity, interfollicular CD10 positivity, and elevated Ki67 proliferation index ≥30% within neoplastic follicles were each associated with inferior PFS and a high risk of the early event by PFS status at 24 months. We identify promising biomarkers for FL risk stratification that warrant further validation in phase 3 trials.

Up-regulation of hexokinase II contributes to rituximab-chemotherapy resistance and is a clinically relevant target for therapeutic development.

In order to identify cellular pathways associated with therapy-resistant aggressive lymphoma, we generated rituximab-resistant cell lines (RRCL) and found that the acquirement of rituximab resistance was associated with a deregulation in glucose metabolism and an increase in the apoptotic threshold leading to chemotherapy resistance. Hexokinase II (HKII), the predominant isoform overexpressed in cancer cells, has dual functions of promoting glycolysis as well as inhibiting mitochondrial-mediated apoptosis. We found that RRCL demonstrated higher HKII levels. Targeting HKII resulted in decreased mitochondrial membrane potential, ATP production, cell viability; and re-sensitization to chemotherapy agents. Analyzed gene expression profiling data from diffuse large B-cell lymphoma patients, high-HKII levels were associated with a shorter progression free survival (PFS) and/or overall survival (OS). Our data suggest that over-expression of HKII is associated with resistance to rituximab and chemotherapy agents in aggressive lymphoma and identifies this enzyme isoform as a potential therapeutic target.

A Phase II Trial of Rituximab Combined With Pegfilgrastim in Patients With Indolent B-cell Non-Hodgkin Lymphoma.

BACKGROUND: To explore the role of augmenting neutrophil function in B-cell lymphoma, we conducted a phase II study evaluating the safety and clinical efficacy of pegfilgrastim and rituximab in low-grade CD20+ B-cell non-Hodgkin lymphoma (B-NHL). PATIENTS AND METHODS: Twenty patients with indolent B-NHL were treated with rituximab (375 mg/m2) every other week for 4 doses, followed by every 2 months for 4 additional doses. Pegfilgrastim was administered subcutaneously 3 days before each dose of rituximab. Clinical activity and tolerability were assessed using standard criteria. Biologic monitoring included phenotype characteristics of the host neutrophils, changes in oxidative burst, and functional assays. RESULTS: The patient demographics included median age of 64 years, 70% were male, 70% had follicular lymphoma, and 90% had stage III-IV disease. The median number of previous therapies was 2 (range, 0-5); 90% had received previous anti-CD20 monoclonal antibody therapy. The addition of pegfilgrastim to rituximab did not increase rituximab-related toxicities. The overall response rate was 60% (12 of 20), with a complete response (CR) rate of 35% (7 of 20). The median progression-free survival (PFS) duration was 17.9 months (95% confidence interval, 9.9-27.6 months); the median overall survival was not reached. A shorter time-to-peak oxidative burst after the first dose of pegfilgrastim was associated with greater CR rates (P = .04) and longer PFS (P = .03). CONCLUSION: The pegfilgrastim-rituximab combination was well tolerated, with favorable outcomes compared with historical controls. A shorter time-to-peak oxidative burst was associated with higher CR rates and longer PFS. Our results support further evaluation of strategies that enhance the innate immune system to improve rituximab activity in B-NHL.

A Phase 2/3 Multicenter, Randomized, Open-Label Study to Compare the Efficacy and Safety of Lenalidomide Versus Investigator's Choice in Patients with Relapsed or Refractory Diffuse Large B-Cell Lymphoma.

Purpose: Randomized, multicenter, open-label, phase 2/3 trial investigating lenalidomide versus investigator's choice (IC) in relapsed/refractory diffuse large B-cell lymphoma (DLBCL).Experimental Design: Patients with DLBCL who received ≥2 prior therapies were stratified by DLBCL subtype [germinal center B-cell (GCB) vs. non-GCB; determined by immunohistochemistry (IHC)] and then randomized 1:1 to lenalidomide (25 mg/day, 21 days of 28-day cycle) or IC (gemcitabine, rituximab, etoposide, or oxaliplatin). Crossover to lenalidomide was permitted for IC-treated patients with radiologically confirmed progressive disease. The primary endpoint was overall response rate (ORR). Progression-free survival (PFS), overall survival, and subtype analysis [GCB vs. activated B-cell (ABC)] using gene expression profiling (GEP) were exploratory endpoints.Results: Stage 1: 102 DLBCL patients (by IHC: non-GCB, n = 54; GCB, n = 48) received ≥1 dose of lenalidomide or IC. Hematologic treatment-emergent adverse events with lenalidomide versus IC included neutropenia (42.6%; 36.4%), anemia (33.3%; 47.3%), thrombocytopenia (24.1%; 43.6%), and leukopenia (5.6%; 12.7%), respectively. Overall, lenalidomide-treated patients had an ORR of 27.5% versus 11.8% in IC (ORRs were similar regardless of IHC-defined DLBCL subtype). Median PFS was increased in patients receiving lenalidomide (13.6 weeks) versus IC (7.9 weeks; P = 0.041), with greater improvements in non-GCB patients (15.1 vs. 7.1 weeks, respectively; P = 0.021) compared with GCB (10.1 vs. 9.0 weeks, respectively; P = 0.550).Conclusions: The clinical benefit of lenalidomide monotherapy in DLBCL patients was more evident in the non-GCB subtype. Exploratory analyses suggest that this preferential benefit was more pronounced in the GEP-defined ABC population, demonstrating a need for additional studies of lenalidomide in DLBCL using GEP subtyping. Clin Cancer Res; 23(15); 4127-37. ©2017 AACR.

Mitotic catastrophe and cell cycle arrest are alternative cell death pathways executed by bortezomib in rituximab resistant B-cell lymphoma cells.

The ubiqutin-proteasome system (UPS) plays a role in rituximab-chemotherapy resistance and bortezomib (BTZ) possesses caspase-dependent (i.e. Bak stabilization) and a less characterized caspase-independent mechanism-of-action(s). Here, we define BTZ-induced caspase-independent cell death pathways. A panel of rituximab-sensitive (RSCL), rituximab-resistant cell lines (RRCL) and primary tumor cells derived from lymphoma patients (N = 13) were exposed to BTZ. Changes in cell viability, cell-cycle, senescence, and mitotic index were quantified. In resting conditions, RRCL exhibits a low-proliferation rate, accumulation of cells in S-phase and senescence. Exposure of RRCL to BTZ reduces cell senescence, induced G2-M phase cell-cycle arrest, and is associated with mitotic catastrophe. BTZ stabilized p21, CDC2, and cyclin B in RRCL and in primary tumor cells. Transient p21 knockdown alleviates BTZ-induced senescence inhibition, G2-M cell cycle blockade, and mitotic catastrophe. Our data suggest that BTZ can induce apoptosis or mitotic catastrophe and that p21 has a pivotal role in BTZ activity against RRCL.

18F-FDG PET for Measurement of Response and Prediction of Outcome to Relapsed or Refractory Mantle Cell Lymphoma Therapy with Bendamustine-Rituximab.

In a single-arm, phase 2 clinical trial, bendamustine-rituximab (BR) demonstrated an overall response rate of 82% among 45 patients with relapsed or refractory mantle cell lymphoma (MCL), with manageable tolerability. A prespecified 18F-FDG PET analysis was conducted to assess the predictive value of the metabolic response to BR compared with the response by International Working Group (IWG) criteria. METHODS: Adult patients with relapsed or refractory MCL underwent 18F-FDG PET at screening and after 6 cycles of BR therapy. Scans were reviewed by a central facility and scored using the 5-point Deauville scale, comparing uptake to the liver and mediastinum in up to 6 lesions, to determine metabolic response rates, indicated by negative posttreatment scans. Metabolic responses were compared with study outcomes assessed by IWG criteria. RESULTS: Complete 18F-FDG PET data were available for 32 of 45 patients. All patients had positive baseline scans, with baseline scores ranging from 4 to 5. Complete metabolic responses (CMR) were observed in 24 (75%) patients after 6 cycles of BR. Patients attaining a CMR had a 96% overall response rate by IWG criteria, with 62.5% achieving a complete response. Of the 8 patients not attaining a CMR, 6 responded to BR but none achieved a complete response. CMR was associated with a greater 1-y progression-free survival of 91.5%, compared with 12.5% without CMR; a longer median duration of response of 20.6 mo, compared with 7.8 mo; and improved overall survival at 1 y. 18F-FDG PET data from patients with refractory or advanced disease demonstrated CMR in more than half. CONCLUSION: Compared with positive end-of-treatment 18F-FDG PET, negative scans, indicating a CMR, were predictive of improved 1-y survival, duration of response, and overall survival for patients with relapsed or refractory MCL receiving BR.

High Body Mass Index in Elderly Patients With DLBCL Treated With Rituximab-Containing Therapy Compensates for Negative Impact of Male Sex.

BACKGROUND: The impact of patient body habitus and sex on outcomes in diffuse large B-cell lymphoma (DLBCL) remains controversial. We investigated the impact of body mass index (BMI), body surface area (BSA), age, and sex on clinical outcomes in patients with DLBCL treated in the rituximab era. PATIENTS AND METHODS: Patients with de novo DLBCL (n=1,386) diagnosed between June 2000 and December 2010 treated with rituximab-containing chemotherapy were identified from the NCCN Oncology Outcomes Database for Non-Hodgkin's Lymphoma. Progression-free survival (PFS) and overall survival (OS) at 3 years were analyzed based on sex, age, and baseline BMI/BSA. RESULTS: High BMI was associated with a lower risk of disease progression or death than low or normal BMI, whereas male sex was associated with poor clinical outcomes, especially among elderly patients (age >60 years). Compared with elderly women, elderly men experienced worse PFS (3-year hazard ratio [HR], 1.5) and OS (3-year HR, 1.6), but these differences diminished with increases in BMI and BSA. In multivariable analysis, normal BMI compared with high BMI was independently associated with poor outcomes (3-year PFS HR, 1.5; OS HR, 1.6) after adjusting for sex. Notably, only 13% of elderly men had BMI less than 25 kg/m2 and only 26% had BSA less than 2 m2 CONCLUSIONS: Analysis of unselected patients with DLBCL treated with rituximab-containing chemotherapy confirmed an age-dependent disadvantage to male sex in treatment outcomes, but this effect is abrogated by higher levels of BMI and BSA in most North American men.

Cardiotoxicity as indicated by LVEF and troponin T sensitivity following two anthracycline-based regimens in lymphoma: Results from a randomized prospective clinical trial.

Anthracycline-induced cardiotoxicity influences treatment selection and may negatively affect clinical outcomes in lymphoma patients. While epirubicin induced cardiotoxicity less often than the same dose of doxorubicin in breast cancer, higher doses of epirubicin are required in lymphoma regimens for equivalent efficacy. Whether a higher dosage of epirubicin also induces cardiotoxicity less often than doxorubicin in lymphoma remains unknown. We therefore administered 6-8 cycles of cyclophosphamide, vincristine and prednisone (CEpOP) +/- rituximab (R) with either epirubicin (CEpOP) or doxorubicin (CHOP) to patients (N=398) with untreated diffuse large B-cell lymphoma (DLBCL) or follicular lymphoma grade 3 (FLG3). Left ventricular ejection fraction (LVEF) and high-sensitivity serum cardiac troponin T (HsTnT) were assessed at baseline and after 4 cycles of treatment. Epirubicin (70 mg/m2/dose) was equivalent to doxorubicin (50 mg/m2/dose) in terms of 3-year progression-free survival. The risk of decreased LVEF was similar between the two regimens. CEpOP+/-R induced HsTnT elevation less often than CHOP+/-R. We conclude that CEpOP+/-R is a more acceptable regimen with short-term efficacy similar to CHOP+/-R in lymphoma patients. Longer follow-up is needed to monitor the risk of cardiac dysfunction and determine whether differences in the induction of elevated HsTnT between epirubicin and doxorubicin justify changes in clinical practice.

Vorinostat, a histone deacetylase (HDAC) inhibitor, promotes cell cycle arrest and re-sensitizes rituximab- and chemo-resistant lymphoma cells to chemotherapy agents.

PURPOSE: Preclinical models of chemotherapy resistance and clinical observations derived from the prospective multicenter phase III collaborative trial in relapsed aggressive lymphoma (CORAL) study demonstrated that primary refractory/relapsed B cell diffuse large B cell lymphoma has a poor clinical outcome with current available second-line treatments. Preclinically, we found that rituximab resistance is associated with a deregulation on the mitochondrial potential rendering lymphoma cells resistant to chemotherapy-induced apoptotic stimuli. There is a dire need to develop agents capable to execute alternative pathways of cell death in an attempt to overcome chemotherapy resistance. Posttranscriptional histone modification plays an important role in regulating gene transcription and is altered by histone acetyltransferases (HATs) and histone deacetylases (HDACs). HDACs regulate several key cellular functions, including cell proliferation, cell cycle, apoptosis, angiogenesis, migration, antigen presentation, and/or immune regulation. Given their influence in multiple regulatory pathways, HDAC inhibition is an attractive strategy to evaluate its anti-proliferation activity in cancer cells. To this end, we studied the anti-proliferation activity and mechanisms of action of suberoylanilide hydroxamic acid (SAHA, vorinostat) in rituximab-chemotherapy-resistant preclinical models. METHODS: A panel of rituximab-chemotherapy-sensitive (RSCL) and rituximab-chemotherapy-resistant cell lines (RRCL) and primary tumor cells isolated from relapsed/refractory B cell lymphoma patients were exposed to escalating doses of vorinostat. Changes in mitochondrial potential, ATP synthesis, and cell cycle distribution were determined by Alamar blue reduction, Titer-Glo luminescent assays, and flow cytometric, respectively. Protein lysates were isolated from vorinostat-exposed cells, and changes in members of Bcl-2 family, cell cycle regulatory proteins, and the acetylation status of histone H3 were evaluated by Western blotting. Finally, cell lines were pre-exposed to vorinostat for 48 h and subsequently exposed to several chemotherapy agents (cisplatin, etoposide, or gemcitabine); changes in cell viability were determined by CellTiter-Glo(®) luminescence assay (Promega, Fitchburg, WI), and synergistic activity was evaluated using the CalcuSyn software. RESULTS: Vorinostat induced dose-dependent cell death in RRCL and in primary tumor cells. In addition, in vitro exposure of RRCL to vorinostat resulted in an increase in p21 and acetylation of histone H3 leading to G1 cell cycle arrest. Vorinostat exposure resulted in apoptosis in RSCL cell lines but not in RRCL. This finding suggests that in RRCL, vorinostat induces cell death by alternative pathways (i.e., irreversible cell cycle arrest). Of interest, vorinostat was found to reverse acquired chemotherapy resistance in RRCL. CONCLUSIONS: Our data suggest that vorinostat is active in RRCL with a known defective apoptotic machinery, it can active alternative cell death pathways. Given the multiple pathways affected by HDAC inhibition, vorinostat can potentially be used to overcome acquired resistant to chemotherapy in aggressive B cell lymphoma.

Pevonedistat, a NEDD8-activating enzyme inhibitor, is active in mantle cell lymphoma and enhances rituximab activity in vivo.

Mantle cell lymphoma (MCL) is characterized by an aggressive clinical course and inevitable development of refractory disease, stressing the need to develop alternative therapeutic strategies. To this end, we evaluated pevonedistat (MLN4924), a novel potent and selective NEDD8-activating enzyme inhibitor in a panel of MCL cell lines, primary MCL tumor cells, and 2 distinct murine models of human MCL. Pevonedistat exposure resulted in a dose-, time-, and caspase-dependent cell death in the majority of the MCL cell lines and primary tumor cells tested. Of interest, in the MCL cell lines with lower half-maximal inhibitory concentration (0.1-0.5 µM), pevonedistat induced G1-phase cell cycle arrest, downregulation of Bcl-xL levels, decreased nuclear factor (NF)-κB activity, and apoptosis. In addition, pevonedistat exhibited additive/synergistic effects when combined with cytarabine, bendamustine, or rituximab. In vivo, as a single agent, pevonedistat prolonged the survival of 2 MCL-bearing mouse models when compared with controls. Pevonedistat in combination with rituximab led to improved survival compared with rituximab or pevonedistat monotherapy. Our data suggest that pevonedistat has significant activity in MCL preclinical models, possibly related to effects on NF-κB activity, Bcl-xL downregulation, and G1 cell cycle arrest. Our findings support further investigation of pevonedistat with or without rituximab in the treatment of MCL.

Obinutuzumab (GA101) compared to rituximab significantly enhances cell death and antibody-dependent cytotoxicity and improves overall survival against CD20(+) rituximab-sensitive/-resistant Burkitt lymphoma (BL) and precursor B-acute lymphoblastic leukaemia (pre-B-ALL): potential targeted therapy in patients with poor risk CD20(+) BL and pre-B-ALL.

Obinutuzumab is a novel glycoengineered Type-II CD20 monoclonal antibody. CD20 is expressed in approximately 100% of children and adolescents with Burkitt lymphoma (BL) and 40% with precursor B-cell acute lymphoblastic leukaemia (pre-B-ALL). We evaluated the anti-tumour activity of obinutuzumab versus rituximab against rituximab-resistant (Raji 4RH) and -sensitive (Raji) BL and pre-B-ALL (U698-M) cells in vitro and in human BL or Pre-B-ALL xenografted mice. We demonstrated that obinutuzumab compared to rituximab significantly enhanced cell death against Raji 35·6 ± 3·1% vs. 25·1 ± 2·0%, (P = 0·001), Raji4RH 19·7 ± 2·2% vs. 7·9 ± 1·5% (P = 0·001) and U-698-M 47·3 ± 4·9% vs. 23·2 ± 0·5% (P = 0·001), respectively. Obinutuzumab versus rituximab also induced a significant increase in antibody-dependent cellular cytotoxicity (ADCC) with K562-IL15-41BBL expanded NK cells against Raji 73·8 ± 8·1% vs. 56·81 ± 4·6% (P = 0·001), Raji-4RH 40·0 ± 1·6% vs. 0·5 ± 1·1% (P = 0·001) and U-698-M 70·0 ± 1·6% vs. 45·5 ± 0·1% (P = 0·001), respectively. Overall survival in tumour xenografted mice receiving 30 mg/kg of obinutuzumab was significantly increased when compared to those receiving 30 mg/kg of rituximab in BL; Raji (P = 0·05), Raji4RH (P = 0·02) and U698-M (P = 0·03), respectively. These preclinical data suggest obinutuzumab is significantly superior to rituximab in inducing cell death, ADCC and against rituximab-sensitive/-resistant BL and pre-B-ALL xenografted mice. Taken together, these preclinical results provide evidence to suggest that future investigation of obinutuzumab is warranted in patients with relapsed/refractory CD20(+) BL and/or pre-B-ALL.

Phase II study of bendamustine combined with rituximab in relapsed/refractory mantle cell lymphoma: efficacy, tolerability, and safety findings.

In most cases of relapsed/refractory mantle cell lymphoma (MCL), patients respond to salvage therapy, though typically responses are partial and/or transient followed by disease progression, even with newer agents (e.g., ibrutinib). In this multicenter, open-label, single-arm, phase II study, patients with relapsed/refractory non-blastoid MCL received bendamustine 90 mg/m(2) (days 1 and 2) and rituximab 375 mg/m(2) (day 1) for 6 planned 28-day cycles. Functional imaging with 18-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (18F-FDG PET/CT) was conducted at baseline and after cycle 6. Forty-five patients were enrolled (median age, 70 years; 82 % stage IV disease; median number of prior chemotherapies, 2 [range, 1-4]), showing an overall response rate (ORR; primary efficacy measure) of 82 % (complete response [CR], 40 %; partial response, 42 %). In the 32 patients with complete 18F-FDG PET/CT data, 75 % achieved a complete metabolic response. Median duration of response was 1.6 years, 1-year progression-free survival was 67 %, and 3-year overall survival was 55 %. Main non-hematologic adverse events were nausea (69 %), fatigue (56 %), decreased appetite (42 %), constipation (38 %), diarrhea (36 %), vomiting (36 %), and decreased weight (31 %). Grade 3/4 neutropenia and lymphopenia occurred in 44 and 89 % of patients, respectively. ORR and CR rate compared favorably with single-agent ibrutinib (ORR, 67 %; CR, 23 %); bendamustine-rituximab is an effective therapy with manageable toxicity in relapsed/refractory MCL.

ABC, GCB, and Double-Hit Diffuse Large B-Cell Lymphoma: Does Subtype Make a Difference in Therapy Selection?

Personalized therapy for the treatment of patients with cancer is rapidly approaching and is an achievable goal in the near future. A substantial number of novel targets have been developed into therapeutic agents. There is a substantial variability to antitumor activity by novel therapeutics because of the unique heterogeneity and biology that exists both between and within lymphoma subtypes. Diffuse large B-cell lymphoma (DLBCL) is the most common subtype of non-Hodgkin lymphoma (NHL). Approximately 40% of patients have refractory disease or disease that will relapse after an initial response, and the majority of patients with relapsed DLBCL will succumb to the disease. There are two major biologically distinct molecular subtypes of DLBCL: germinal center B-cell (GCB) and activated B-cell (ABC). ABC DLBCL is associated with substantially worse outcomes when treated with standard chemoimmunotherapy. In addition to GCB and ABC subtypes, double-hit lymphomas (approximately 5% to 10% of patients) and double-expressor lymphomas, which overexpress MYC and BCL2 protein, are aggressive DLBCLs and are also associated with a poor prognosis. Double-hit lymphomas have concurrent chromosomal rearrangements of MYC plus BCL2 (or less likely, BCL6). Advances in molecular characterization techniques and the development of novel agents targeting specific subtypes of DLBCL have provided a foundation for personalized therapy of DLBCL based on molecular subtype. A number of early clinical trials evaluating combinations of novel targeted agents with standard chemotherapy (R-CHOP) have been completed and have demonstrated the feasibility of this approach with encouraging efficacy. As such, molecular classification of DLBCL is not only important for prognostication, but moves to center stage for personalization of therapy for DLBCL.

Ofatumumab Exhibits Enhanced In Vitro and In Vivo Activity Compared to Rituximab in Preclinical Models of Mantle Cell Lymphoma.

PURPOSE: Mantle cell lymphoma (MCL) is a mature B-cell lymphoma considered to be incurable with current treatments, including first-line rituximab in combination with multiagent chemotherapy and for those eligible, high-dose chemotherapy and stem cell support or rituximab maintenance. On the other hand, achieving a complete remission by high-sensitive flow cytometry is associated with prolonged duration of remission, stressing the need to develop and/or incorporate novel agents into the management of MCL. To this end, we examined the activity of ofatumumab, an anti-CD20 monoclonal antibody with distinct binding and immunologic properties compared to rituximab, in MCL preclinical models. EXPERIMENTAL DESIGN: MCL cells were labeled with (51)Cr before incubation with rituximab or ofatumumab (10 µg/mL) plus human serum or effector cells. (51)Cr-release was measured and the percentage of lysis was calculated. Surface CD20, CD55, and CD59 were measured by Imagestream analysis. SCID mice inoculated subcutaneously with Z138 cells were assigned to control versus four doses of ofatumumab or rituximab (10 mg/kg/dose). RESULTS: Ofatumumab exhibited enhanced in vitro complement-dependent cytotoxicity activity compared with rituximab in MCL cell lines, despite a high degree of in vitro resistance to rituximab associated with low CD20 levels and/or high expression of complement inhibitory proteins. Ofatumumab also delayed tumor progression and prolonged survival in a murine model of MCL. CONCLUSIONS: Our results demonstrate that ofatumumab is more effective than rituximab in MCL preclinical models, including in the presence of rituximab resistance, and support the clinical investigation of ofatumumab in combination with standard systemic chemotherapy in MCL (NCT01527149).

Chronic lymphocytic leukemia/small lymphocytic lymphoma, version 1.2015.

Chronic lymphocytic leukemia (CLL) and small lymphocytic lymphoma (SLL) are different manifestations of the same disease, which are managed in the same way. The advent of novel monoclonal antibodies (ofatumumab and obinutuzumab) led to the development of effective chemoimmunotherapy regimens. The recently approved small molecule kinase inhibitors (ibrutinib and idelalisib) are effective treatment options for CLL in elderly patients with decreased tolerance for aggressive regimens and in patients with poor prognostic features who do not benefit from conventional chemoimmunotherapy regimens. This portion of the NCCN Guidelines for Non-Hodgkin's Lymphomas describes the recent specific to the incorporation of recently approved targeted therapies for the management of patients with newly diagnosed and relapsed or refractory CLL/SLL.

Entinostat, a novel histone deacetylase inhibitor is active in B-cell lymphoma and enhances the anti-tumour activity of rituximab and chemotherapy agents.

Histone deacetylases (HDACs) inhibitors are active in T-cell lymphoma and are undergoing pre-clinical and clinical testing in other neoplasms. Entinostat is an orally bioavailable class I HDAC inhibitor with a long half-life, which is under evaluation in haematological and solid tumour malignancies. To define the activity and biological effects of entinostat in B-cell lymphoma we studied its anti-tumour activity in several rituximab-sensitive or -resistant pre-clinical models. We demonstrated that entinostat is active in rituximab-sensitive cell lines (RSCL), rituximab-resistant cell lines (RRCL) and primary tumour cells isolated from lymphoma patients (n = 36). Entinostat exposure decreased Bcl-XL (BCL2L1) levels and induced apoptosis in cells. In RSCL and RRCL, entinostat induced p21 (CDKN1A) expression leading to G1 cell cycle arrest and exhibited additive effects when combined with bortezomib or cytarabine. Caspase inhibition diminished entinostat activity in some primary tumour cells suggesting that entinostat has dual mechanisms-of-action. In addition, entinostat increased the expression of CD20 and adhesion molecules. Perhaps related to these effects, we observed a synergistic activity between entinostat and rituximab in a lymphoma-bearing severe combined immunodeficiency (SCID) mouse model. Our data suggests that entinostat is an active HDAC inhibitor that potentiates rituximab activity in vivo and supports its further clinical development in B-cell lymphoma.

Results of a phase II study of bendamustine and ofatumumab in untreated indolent B cell non-Hodgkin's lymphoma.

The efficacy/tolerability of bendamustine, a unique alkylator, plus ofatumumab, a human anti-CD20 monoclonal antibody, was evaluated for previously untreated indolent B cell non-Hodgkin's lymphoma (NHL). The study investigated whether the overall response rate (ORR) for bendamustine-ofatumumab was similar to historical bendamustine-rituximab ORRs (≥90 %). In this multicenter, open-label, single-arm, phase II study, patients received six planned 28-day cycles of bendamustine (90 mg/m(2) on days 1 and 2 of each cycle) and ofatumumab (300 mg on day 1, 1000 mg on day 8 of cycle 1, and on day 1 of subsequent cycles). The primary outcome was ORR. Secondary objectives included safety and tolerability. Exploratory evaluations included percentage of patients with positive baseline [(18)F]fluorodeoxyglucose positron emission tomography (FDG-PET) scans who converted to negative postbaseline and quality of life (QOL) scores. The treated/safety analysis population received ≥1 dose of either therapy. The bendamustine-ofatumumab ORR was 90 % (95 % confidence interval, 77.8-96.6) in 49 treated patients (67 % complete response, 22 % partial response). No patients had progressive disease. Bendamustine-ofatumumab was acceptably tolerated. All 49 patients had ≥1 adverse event, the most common being nausea (61 %), fatigue (55 %), and infusion-related reactions (45 %, all but 1 occurring during cycle 1). The proportion of patients whose FDG-PET scans converted to negative postbaseline was 88 %. Changes in QOL scores were minor. In patients with treatment-naive, indolent B cell NHL, bendamustine-ofatumumab exhibited a high degree of activity (90 % ORR), comparable with historical bendamustine-rituximab ORRs (≥90 %), and was adequately tolerated ( ClinicalTrials.gov identifier: NCT01108341).

Radiation for diffuse large B-cell lymphoma in the rituximab era: analysis of the National Comprehensive Cancer Network lymphoma outcomes project.

BACKGROUND: The role of consolidation radiotherapy was examined for patients with diffuse large B-cell lymphoma who were treated at institutions of the National Comprehensive Cancer Network during the rituximab era. METHODS: Failure-free survival (FFS) and overall survival (OS) were analyzed in terms of patient and treatment characteristics. Potential associations were investigated with univariate and multivariate survival analysis and matched pair analysis. RESULTS: There were 841 patients, and most (710 or 84%) received 6 to 8 cycles of rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP); 293 (35%) received consolidation radiation therapy (RT). Failure occurred for 181 patients: 126 patients (70%) who did not receive RT and 55 patients (30%) who did. At 5 years, both OS and FFS rates were better for patients who had received RT versus those who did not (OS, 91% vs 83% [P = .01]; FFS, 83% vs 76% [P = .05]). A matched pair analysis (217 pairs matched by age, stage, International Prognostic Index [IPI] score, B symptoms, disease bulk, and response to chemotherapy) showed that the receipt of RT improved OS (hazard ratio [HR], 0.53 [P = .07]) and FFS (HR, 0.77 [P = .34]) for patients with stage III/IV disease, but too few events took place among those with stage I/II disease for meaningful comparisons (HR for OS, 0.94 [P = .89]; HR for FFS, 1.81 [P = .15]). A multivariate analysis suggested that the IPI score and the response to chemotherapy had the greatest influence on outcomes. CONCLUSIONS: There was a trend of higher OS and FFS rates for patients who had received consolidation RT after R-CHOP (especially for patients with stage III/IV disease), but the difference did not reach statistical significance.

(18)F-fluorodeoxyglucose-positron emission tomography/computed tomography after one cycle of chemotherapy in patients with diffuse large B-cell lymphoma: results of a Nordic/US intergroup study.

We evaluated the predictive value of interim positon emission tomography (I-PET) after one course of chemoimmunotherapy in patients with newly diagnosed diffuse large B-cell lymphoma (DLBCL). One hundred and twelve patients with DLBCL were enrolled. All patients had PET/computed tomography (CT) scans performed after one course of chemotherapy (PET-1). I-PET scans were categorized according to International Harmonization Project criteria (IHP), Deauville 5-point scale (D 5PS) with scores 1-3 considered negative (D 5PS > 3) and D 5PS with scores 1-4 considered negative (D 5PS = 5). Ratios of tumor maximum standardized uptake value (SUVmax) to liver SUVmax were also analyzed. We found no difference in progression-free survival (PFS) between PET-negative and PET-positive patients according to IHP and D 5PS > 3. The 2-year PFS using D 5PS = 5 was 50.9% in the PET-positive group and 84.8% in the PET-negative group (p = 0.002). A tumor/liver SUVmax cut-off of 3.1 to distinguish D 5PS scores of 4 and 5 provided the best prognostic value. PET after one course of chemotherapy was not able to safely discriminate PET-positive and PET-negative patients in different prognostic groups.