Current management of follicular lymphomas

In vivo anti-tumor efficacy of afucosylated anti-CS1 monoclonal antibody produced in glycoengineered Pichia pastoris

Monoclonal antibody (mAb) therapy has been successfully used for the treatment of B-cell lymphomas and is currently extended for the treatment of multiple myeloma (MM). New developments in MM therapeutics have achieved significant survival gains in patients but the disease still remains incurable. Elotuzumab (HuLuc63), an anti-CS1 monoclonal IgG1 antibody, is believed to induce anti-tumor activity and MM cytotoxicity through antibody dependent cellular cytotoxicity (ADCC) and inhibition of MM cell adhesion to bone marrow stromal cells (BMSCs). Modulations of the Fc glycan composition at the N297 site by selective mutations or afucosylation have been explored as strategies to develop bio-better therapeutics with enhanced ADCC activity. Afucosylated therapeutic antibodies with enhanced ADCC activity have been reported to possess greater efficacy in tumor growth inhibition at lower doses when compared to fucosylated therapeutic antibodies. The N-linked glycosylation pathway in Pichia pastoris has been engineered to produce human-like N-linked glycosylation with uniform afucosylated complex type glycans. The purpose of this study was to compare afucosylated anti-CS1 mAb expressed in glycoengineered Pichia pastoris with fucosylated anti-CS1 mAb expressed in mammalian HEK293 cells through in vitro ADCC and in vivo tumor inhibition models. Our results indicate that Fc glycosylation is critical for in vivo efficacy and afucosylated anti-CS1 mAb expressed in glycoengineered Pichia pastoris shows a better in vivo efficacy in tumor regression when compared to fucosylated anti-CS1 mAb expressed in HEK293 cells. Glycoengineered Pichia pastoris could provide an alternative platform for generating homogeneous afucosylated recombinant antibodies where Fc mediated immune effector function is important for efficacy.

Efficacy and toxicity of two schedules of bortezomib in patients with recurrent or refractory follicular lymphoma: a randomised phase II trial from the Groupe d'Etude des Lymphomes de l'Adulte (GELA)

PURPOSE

Bortezomib has previously demonstrated activity in indolent lymphomas including follicular lymphoma with response rate ranging from 13% to 56%. However, the optimal schedule of bortezomib remains to be investigated in follicular lymphoma.

EXPERIMENTAL DESIGN

We conducted a randomised phase II study where patients with follicular lymphoma in relapse or refractory receive either bortezomib 1.5 mg/m(2) biweekly on days 1, 4, 8 and 11 of a 21-day cycle (arm A) or 1.6 mg/m(2) weekly on days 1, 8, 15 and 22 of a 35-day cycle (arm B). An interim analysis was planned after 15 fully evaluable patients randomised in each treatment arm. If only five subjects or fewer respond, the treatment arm was concluded to be ineffective and was closed to inclusion.

RESULTS

Eighty-seven patients were included in the trial. Arm B was closed to inclusion after interim analysis. 15/50 patients (30%) in arm A and 8/37 patients (22%) in arm B achieved a response. Median duration of response was 16 and 15 months for arms A and B, respectively. Most drug-related adverse events (AEs) (all grades, all cycles) were mild.

CONCLUSION

This study demonstrates tolerability and durable clinical benefit of bortezomib when given at 1.5 mg/m(2) biweekly. Despite a higher response rate in the biweekly arm, no major difference in patient's outcome was observed between the two arms in the final analysis.

Non-gastric marginal zone B cell lymphoma: clinicopathologic features and treatment results

The optimal treatment strategy and outcome of non-gastric marginal zone lymphoma (MZL) remains undefined. The role of rituximab and fludarabine in MZL has not been critically appraised and compared with conventional chemotherapy. We retrospectively analyzed 81 consecutive patients with non-gastric MZL (mucosa-associated lymphoid tissue lymphoma, n = 66; splenic MZL, n = 11; nodal MZL, n = 4). As a group, the treatment results were favorable, with an overall response rate of 87% and a complete response (CR) rate of 73%. The CR rate was similar for conventional chemotherapy, and rituximab- and fludarabine-containing regimens. However, the relapse rate was significantly decreased in rituximab- and fludarabine-containing regimens. The use of rituximab and fludarabine was associated with acceptable side effects. For splenic MZL, splenectomy was significantly associated with a superior CR rate. Early stage, good performance status, and low international prognostic index risk scores significantly impacted on CR rate and survivals. Rituximab and fludarabine were safe for non-gastric MZL and resulted in more durable remissions.

Current immunochemotherapy strategies in follicular lymphoma

Nowadays, there is no consensus about the best treatment for patients with follicular lymphoma (FL) in differing situations. In frontline treatment, a watchful waiting policy remains a good option if the patient has no risk criteria; the role of rituximab is under investigation in this setting. In patients needing therapy, immunotherapy or immunochemotherapy are the best options; although it has not been established which chemotherapy, including cyclophosphamide, vincristine, and prednisone (CVP); cyclophosphamide, adriamycin, vincristine, and prednisone (CHOP); fludarabine, or bendamustine combinations, is the best partner for rituximab. Following frontline treatment, recent and still unpublished data strongly suggest a role for maintenance with rituximab, instead of observation only. At relapse, immunochemotherapy is the standard induction approach. The role of maintenance after induction is well established, although comparative studies with autologous stem-cell transplantation (ASCT) or other combinations are warranted. The role of ASCT in this setting is a matter of discussion. Other monoclonal antibodies, as well as vaccines and other immunotherapies, are currently under investigation. Finally, allogeneic transplantation should be reserved for a very select group of young high-risk patients in the setting of clinical trials.

Malignant lymphoma of the head and neck

Malignant lymphomas represent approximately 5% of all malignant neoplasms of the head and neck area. They are classically divided into two subgroups, Hodgkin's lymphomas (HLs) and non-Hodgkin's lymphomas (NHLs). We describe the clinical characteristics of head and neck lymphomas and the methods to establish the diagnosis. The World Health Organization classification of lymphoid tissues describes more than 50 different histological types, and we analyse the most common staging system for lymphomas, the Ann Arbor staging system. Finally, the different therapeutic approaches are discussed.

Non-Hodgkin's lymphoma in the elderly

The expansion of older population segments and the continuous increase in the incidence of non-Hodgkin's lymphoma (NHL) makes this group of neoplasms an important and growing problem. Older NHL patients have increased risk of therapy-related toxicity as a result of age-related physiological changes and frequent co-morbidities. A functional assessment of the elderly patient is necessary to determine the likelihood of tolerating and responding to therapy. The comprehensive geriatric assessment (CGA) is one multidisciplinary tool that has been applied successfully to older cancer patients and aids in identification of subjects who will or will not benefit from anti-neoplastic treatment. Although indolent lymphomas present more frequently at advanced stage, randomized trials do not show better outcomes with early therapy, supporting close observation until specific therapeutic indications arise. Use of the monoclonal antibody rituximab as a single agent or in combination with chemotherapy improves survival and has become the standard of care in first-line treatment. Radioimmunoconjugates, bendamustine, and other monoclonal antibodies as well as novel targeted agents also are active against indolent lymphomas. Diffuse large B-cell lymphoma is an aggressive but potentially curable disease. Several trials performed exclusively in elderly patients have demonstrated improved response rates and survival with the addition of rituximab to CHOP (cyclophosphamide, doxorubicin [adriamycin], vincristine, prednisone) chemotherapy in the front-line setting. Salvage chemotherapy followed by autologous haematopoietic cell transplant (autoHCT) has been shown to have better failure-free and overall survival in randomized trials involving younger patients. Highly selected individuals up to age 70 years may attain long-term survival benefit from autoHCT, although transplant-related mortality is higher than in younger patients.

Lymphoma stem cells: enough evidence to support their existence?

While leukemia-originating stem cells are critical in the initiation and maintenance of leukemias, the existence of similar cell populations that may generate B-cell lymphoma upon mutation remains uncertain. Here we propose that committed lymphoid progenitor/precursor cells with an active V-D-J recombination program are the initiating cells of follicular lymphoma and mantle cell lymphoma when targeted by immunoglobulin (IG)- gene translocations in the bone marrow. However, these pre-malignant lymphoma-initiating cells cannot drive complete malignant transformation, requiring additional cooperating mutations in specific stem-cell programs to be converted into the lymphoma-originating cells able to generate and sustain lymphoma development. Conversely, diffuse large B-cell lymphoma and sporadic Burkitt's lymphoma derive from B lymphocytes that acquire translocations through IG-hyper-mutation or class-switching errors within the germinal center. Although secondary reprogramming mutations are generally required, some cells such as centroblasts or memory B cells that have certain stem cell-like features, or lymphocytes with MYC rearrangements that deregulate self-renewal pathways, may bypass this need and directly function as the lymphoma-originating cells. An alternative model supports an aberrant epigenetic modification of gene sets as the first occurring hit, which either leads to retaining stem-cell features in hematopoietic stem or progenitor cells, or reprograms stemness into more committed lymphocytes, followed by secondary chromosomal translocations that eventually drive lymphoma development. Isolation and characterization of the cells that are at the origin of the different B-cell non-Hodgkin's lymphomas will provide critical insights into the disease pathogenesis and will represent a step towards the development of more effective therapies.

Multicenter Randomized Phase II Study of Weekly or Twice-Weekly Bortezomib Plus Rituximab in Patients With Relapsed or Refractory Follicular or Marginal-Zone B-Cell Lymphoma

Purpose

To determine overall response rate (ORR), time to progression (TTP), and duration of response (DOR) with twice-weekly/weekly bortezomib plus rituximab, and evaluate safety/tolerability, in patients with relapsed or refractory CD20+ follicular lymphoma (FL) or marginal-zone lymphoma.

Patients and Methods

Patients were randomly assigned (minimization method) to bortezomib 1.3 mg/m2 twice weekly (days 1, 4, 8, and 11; 21-day cycle, five cycles; arm A) or bortezomib 1.6 mg/m2 weekly (days 1, 8, 15, and 22; 35-day cycle, three cycles; arm B) plus rituximab 375 mg/m2 weekly for 4 weeks (both arms). Response/progression was determined by International Workshop Response Criteria using oncologist/radiologist-adjudicated data from independent radiology review and investigator assessment.

Results

Eighty-one patients (arm A, n = 41; arm B, n = 40) were enrolled. Dose-intensity was higher in arm A; mean total bortezomib received was similar between arms (18.5 and 17.1 mg/m2). In arm A, ORR was 49% (14% complete response [CR]/CR unconfirmed [CRu]), median TTP was 7.0 months, and median DOR was not reached. In arm B, ORR was 43% (10% CR/CRu), and median TTP/DOR were 10.0/9.3 months. The weekly combination regimen seemed better tolerated. Grade 3 or worse adverse events seemed more common in arm A (54%) versus arm B (35%), including thrombocytopenia (10% v 0%) and peripheral neuropathy (10% v 5%), but diarrhea seemed less frequent (7% v 15%). No grade 4 toxicities were reported in arm B.

Conclusion

Both bortezomib plus rituximab regimens seem feasible in relapsed or refractory indolent lymphomas. The more convenient weekly combination regimen is being compared with single-agent rituximab in an ongoing phase III study in relapsed FL.

Rituximab-associated changes in platelet count in patients with non-Hodgkin lymphoma

Rituximab is a monoclonal antibody specific for the CD20 antigen. Clinical factors associated with thrombocytopenia after administration of rituximab have only been reported as case reports. We have analysed retrospectively the change of platelet counts following the administration of rituximab in 253 patients with non-Hodgkin lymphoma (NHL). Correlations with clinical and laboratory parameters were assessed. A mean overall decrease in platelets was observed after rituximab infusion. A downward trend in platelet count of more than 30% was observed in 7.2% of the patients. The decline was observed when rituximab was given as a single agent or in combination with chemotherapy. The risk factors to develop a decline in platelets after infusion of rituximab were pre-existent thrombocytopenia, advanced lymphoma stage, bone marrow infiltration, splenomegaly, leukemic presentation, and Burkitt lymphoma histology. In conclusion, a decline in platelet count after administration of rituximab was observed in patients with NHL, mainly those with pre-existing thrombocytopenia.

p37Ing1b regulates B-cell proliferation and cooperates with p53 to suppress diffuse large B-cell lymphomagenesis

The Inhibitor of Growth (ING) gene family encodes structurally related proteins that alter chromatin to regulate gene expression and cell growth. The initial member, ING1, has also been proposed to function as a tumor suppressor in human cancer based on its ability to suppress cell growth and transformation in vitro. Mouse Ing1 produces two proteins (p31 and p37) from differentially spliced transcripts. We have recently generated p37(Ing1b)-null mice and observed spontaneous follicular B-cell lymphomagenesis in this model to show that ING proteins can function in vivo as tumor suppressors. In this present report, we examine the role of p37(Ing1b) in the regulation of B-cell growth and explore the relationship between p37(Ing1b) and p53-mediated tumor suppression. Our results indicate that p37(Ing1b) inhibits the proliferation of B cells and follicular B cells regardless of p53 status, and loss of p53 greatly accelerates the rate of B-cell lymphomagenesis in p37(Ing1b)-null mice. However, in contrast to the highly penetrant follicular B-cell lymphomas observed in p37(Ing1b)-null mice, mice lacking both p37(Ing1b) and p53 typically present with aggressive diffuse large B-cell lymphomas (DLBL). Analysis of marker gene expression in p37(Ing1b)/p53 null tumors indicates that the double-null mice develop both nongerminal center and germinal center B-cell-like DLBL, and also documents up-regulation of nuclear factor-kappaB activity in p37(Ing1b)/p53-null B cells and B-cell tumors. These results confirm that p53 mutation is an important mechanistic step in the formation of diffuse large B-cell lymphomas and reveals a p53-independent role for Ing1b in suppressing B-cell tumorigenesis.