Strategies to enhance rituximab anti-tumor activity in the treatment of CD20-positive B-cell neoplasms

The Effect of FcγRIIIA Gene Polymorphism on the Treatment of Diffuse Large B-cell Non-Hodgkin Lymphoma: A Multicenter Prospective Observational Study

Objective:

The curative treatment approach for diffuse large B-cell lymphoma (DLBCL) is controversial even in the rituximab (R) era. The aim of this study was to examine the FcγRIIIA gene polymorphism distribution of DLBCL patients who had been treated with R-CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisone) chemotherapy. Furthermore, we investigated the impact of FcγRIIIA gene polymorphism on the overall response rate (ORR) and overall survival (OS).

Materials and Methods:

Patients from 3 centers in the Aegean region of Turkey who had newly diagnosed CD20-positive DLBCL were enrolled in the study. The single nucleotide polymorphisms of the FcγRIIIA gene were analyzed by real time-PCR. The response to treatment was determined in the middle and at the end of the protocol. During 2 years of follow-up, the patients were clinically and radiologically evaluated for disease status every 3 months.

Results:

Thirty-six patients were included in the study and the distributions of F/F, V/F, and V/V types of alleles of FcγRIIIA were 25%, 50%, and 25%, respectively. Twenty-seven patients were considered as evaluable according to ORR and OS. The patients’ ORR was 87.5%, 100%, and 50% in the F/F, V/F, and V/V allele groups, respectively. We did not establish any statistically significant differences among the 3 alleles groups in respect to ORR (p=0.93). The OS within 2 years in the F/F, V/F, and V/V allele groups was 62.5%, 100%, and 100%, respectively. The OS in the F/F allele group was found to be lower than in the other 2 allele groups (p=0.01).

Conclusion:

The distribution of gene polymorphisms in our study group was similar to those of previous studies. While ORR was similar between the groups, our results highlight a lower OS in F/F patients compared to other allele groups of FcγRIIIA.

Oncolytic reovirus enhances rituximab-mediated antibody-dependent cellular cytotoxicity against chronic lymphocytic leukaemia

The naturally occurring oncolytic virus (OV), reovirus, replicates in cancer cells causing direct cytotoxicity, and can activate innate and adaptive immune responses to facilitate tumour clearance. Reovirus is safe, well tolerated and currently in clinical testing for the treatment of multiple myeloma, in combination with dexamethasone/carfilzomib. Activation of natural killer (NK) cells has been observed after systemic delivery of reovirus to cancer patients; however, the ability of OV to potentiate NK cell-mediated antibody-dependent cellular cytotoxicity (ADCC) is unexplored. This study elucidates the potential of oncolytic reovirus for the treatment of chronic lymphocytic leukaemia (CLL), both as a direct cytotoxic agent and as an immunomodulator. We demonstrate that reovirus: (i) is directly cytotoxic against CLL, which requires replication-competent virus; (ii) phenotypically and functionally activates patient NK cells via a monocyte-derived interferon-α (IFNα)-dependent mechanism; and (iii) enhances ADCC-mediated killing of CLL in combination with anti-CD20 antibodies. Our data provide strong preclinical evidence to support the use of reovirus in combination with anti-CD20 immunotherapy for the treatment of CLL.

Anti-CD20 monoclonal antibodies in chronic lymphocytic leukemia

INTRODUCTION

The last decade has witnesd immense progress in the treatment of chronic lymphocytic leukemia (CLL). Chemoimmunotherapy (CIT) combining rituximab and fludarabine with cyclophosphamide (FCR) in the frontline setting has clearly been shown to improve outcomes in patients with CLL. Building on the success achieved with rituximab, other anti-CD20 monoclonal antibodies (mAbs) are being investigated. Novel bioengineering techniques have helped in the development of anti-CD20 mAbs. One antibody, ofatumumab, was recently approved for the treatment of refractory CLL. A type II anti-CD20 mAb, GA-101 (obinutuzumab), is currently in clinical trials. This short review focuses on ongoing clinical trials of anti-CD20 mAbs in CLL.

AREAS COVERED

Literature search was performed using PubMed ( www.clinicaltrials.gov (till August 2012)), and recent American Society of Clinical Oncology (ASCO), American Society of Hematology (ASH), European Hematology association (EHA), International workshop on CLL (iwCLL) abstracts, using the primary search terms 'anti-CD20 monoclonal antibody' with/without CLL. Articles were chosen on the basis of relevance of anti-CD20 mAbs to CLL therapy.

EXPERT OPINION

Rituximab, the prototype anti-CD20 mAb, forms the core of CIT in CLL. The success of rituximab and ofatumumab has led investigators to evaluate other anti-CD20 mAbs in the treatment of CLL.

Polymer-drug conjugates: origins, progress to date and future directions

This overview focuses on bioconjugates of water-soluble polymers with low molecular weight drugs and proteins. After a short discussion of the origins of the field, the state-of-the-art is reviewed. Then research directions needed for the acceleration of the translation of nanomedicines into the clinic are outlined. Two most important directions, synthesis of backbone degradable polymer carriers and drug-free macromolecular therapeutics, a new paradigm in drug delivery, are discussed in detail. Finally, the future perspectives of the field are briefly discussed.

Toward personalized therapy for chronic lymphocytic leukemia: DSC and cDNA microarray assessment of two cases

The differences in clinical course of chronic lymphocytic leukemia could have an impact on variations in a patient's response to therapy. Our published results revealed that thermal transition (95 ± 5°C) in differential scanning calorimetry profiles appear to be characteristic for the advanced stage of CLL. Moreover, a decrease/loss of this transition in nuclei from leukemic cells exposed to drugs ex vivo could indicate their diverse efficacy. It seems that the lack of changes in thermal profile could predict patient's drug resistance. In this study, we demonstrate the results obtained after drug treatment of leukemic cells by calorimetry, apoptosis-related parameters involved in expression of genes using cDNA microarray and western blot. These data were compared with the patients' clinical parameters before and after RCC therapy (rituximab + cladribine + cyclophosphamide). The complementary analysis of studied cases with opposite clinical response (CR or NR) revealed a strong relationship between clinical data, differences in thermal scans and apoptosis-related gene expression. We quantified expression of eight of apoptosis-related 89 genes, i.e., NOXA, PUMA, APAF1, ESRRBL1, CASP3, BCL2, BCL2A1 and MCL1. Particular differences in NOXA and BCL2 expression were revealed. NOXA expression in cells of patients who achieved a complete response to RCC therapy was 0.44 times higher in comparison to control ones. Interestingly, in the case of patients who did not respond to immunotherapy, NOXA expression was highly downregulated (RQ = 4.39) as compared with untreated cells. These results were confirmed by distinct cell viability, protein expression as well as by differences in calorimetry profiles.

Coiled-coil based drug-free macromolecular therapeutics: in vivo efficacy

We evaluated a new concept in cancer therapy, coiled-coil mediated induction of apoptosis in Raji B cells, for treatment of human B-cell lymphoma in a preclinical animal model. The system is composed of a pair of complementary coiled-coil peptides, CCE and CCK, forming antiparallel heterodimers; Fab' fragment of the 1F5 anti-CD20 antibody; and N-(2-hydroxypropyl)methacrylamide (HPMA) copolymer. One peptide is conjugated to the Fab' fragment (Fab'-CCE), the other is conjugated in multiple grafts to polyHPMA (CCK-P; P is the HPMA copolymer backbone). Intravenous administration of Fab'-CCE conjugate, followed by the administration of CCK-P produced long-term survivors in SCID (C.B.-17) mice bearing human B-lymphoma xenografts. The rationale of the design is the absence of low molecular weight drugs and the fact that crosslinking of CD20 at B-cell surface results in apoptosis. This approach creates a new paradigm for manipulating molecular recognition principles in the design of improved cancer treatment.

IL-15R alpha-IgG1-Fc enhances IL-2 and IL-15 anti-tumor action through NK and CD8+ T cells proliferation and activation

Natural killer (NK) cells-based immunotherapy is one of the most promising treatments for incurable malignant tumors. NK cells in combination with monoclonal antibodies to surface antigens of the tumor cell have been proved to be effective in a number of clinical trials. A limiting step in the development of successful cellular immunotherapy lies in developing an efficient and economic method to expand appropriate amount of NK cells and CD8(+) T cells. In this study, we constructed a humanized IL-15Ralpha-IgG1-Fc, which mimicked IL-15 trans-presentation. The feasibility of expanding populations of the human NK and CD8(+) T cells by IL-15Ralpha-IgG1-Fc complexes was tested. We then measured the cytotoxicity of expanded NK and CD8(+) T cells against tumor cell lines and primary tumor cells. When tested ex vivo, IL-2/IL-15Ralpha-IgG1-Fc complexes significantly enhanced NK and CD8(+) T cells expansion, isolated or non-isolated from PBMCs. The effect of IL-15Ralpha-IgG1-Fc was dependent on the presence of IL-2 or IL-15. IL-15Ralpha-IgG1-Fc complexes increased NK, CD8(+) T and NKT cells ratio in PBMC and BMMC after 14 days incubation. High level of granzyme B expression was observed in the supernatant of the complexes-treated NK cells. Expanded NK and CD8(+) T cell populations had cytotoxic function against the PC3, LNCaP, K562 and chronic lymphocytic leukemia (CLL) patient primary B cell lymphoma. We concluded that IL-2/IL-15Ralpha-IgG1-Fc significantly enhanced NK, CD8(+) T and NKT cells expansion, which possess strong anti-tumor activity. These data support clinical testing IL-2/IL-15Ralpha-IgG1-Fc expanded NK cells in patients with prostate cancer and CLL.