Combination therapy with the type II anti-CD20 antibody obinutuzumab

Improved Therapy of B-Cell Non-Hodgkin Lymphoma by Obinutuzumab-Dianthin Conjugates in Combination with the Endosomal Escape Enhancer SO1861

Immunotoxins do not only bind to cancer-specific receptors to mediate the elimination of tumor cells through the innate immune system, but also increase target cytotoxicity by the intrinsic toxin activity. The plant glycoside SO1861 was previously reported to enhance the endolysosomal escape of antibody-toxin conjugates in non-hematopoietic cells, thus increasing their cytotoxicity manifold. Here we tested this technology for the first time in a lymphoma in vivo model. First, the therapeutic CD20 antibody obinutuzumab was chemically conjugated to the ribosome-inactivating protein dianthin. The cytotoxicity of obinutuzumab-dianthin (ObiDi) was evaluated on human B-lymphocyte Burkitt’s lymphoma Raji cells and compared to human T-cell leukemia off-target Jurkat cells. When tested in combination with SO1861, the cytotoxicity for target cells was 131-fold greater than for off-target cells. In vivo imaging in a xenograft model of B-cell lymphoma in mice revealed that ObiDi/SO1861 efficiently prevents tumor growth (51.4% response rate) compared to the monotherapy with ObiDi (25.9%) and non-conjugated obinutuzumab (20.7%). The reduction of tumor volume and overall survival was also improved. Taken together, our results substantially contribute to the development of a combination therapy with SO1861 as a platform technology to enhance the efficacy of therapeutic antibody-toxin conjugates in lymphoma and leukemia.

Monoclonal Antibodies, Bispecific Antibodies and Antibody-Drug Conjugates in Oncohematology

Background:

The therapeutic outcomes and the prognosis of patients with various hematologic malignancies are not always ideal with the current standard of care.

Objective:

The aim of this study is to analyze the results of the use of monoclonal antibodies, bispecific antibodies and antibody-drug conjugates for the therapy of malignant hemopathies.

Methods:

A mini-review was achieved using the articles published in Web of Science and PubMed between January 2017 and January 2020 and the new patents were made in this field.

Results:

Naked monoclonal antibodies have improved the therapeutic results obtained with standard of care, but they also have side effects and the use of some of them can lead to the loss of the target antigen through trogocytosis, which explains the resistance that occurs during therapy. The results obtained with naked monoclonal antibodies have been improved by a better monoclonal antibody preparation, the use of bispecific antibodies (against two antigens on the target cell surface or by binding both surface antigen on target cells and T-cell receptor complex, followed by cytotoxic T-lymphocytes activation and subsequent cytolysis of the target cell), the use of monoclonal or bispecific constructs in frontline regimens, combining immunotherapy with chemotherapy, including through the use of antibody-drug conjugates (which provides a targeted release of a chemotherapeutic agent).

Conclusion:

Immunotherapy and immuno-chemotherapy have improved the outcome of the patients with malignant hemopathies through a targeted, personalized therapy, with reduced systemic toxicity, which in some cases can even induce deep complete remissions, including minimal residual disease negativity.

Immunomodulatory Agents in Follicular Lymphoma

New treatment strategies in follicular lymphoma (FL) are driven by a deeper understanding of microenvironmental cues supporting lymphomagenesis, chemoresistance, and immuno-escape. These immune-mediated signaling pathways contribute to initial learnings and clinical successes with lenalidomide, the first, oral, non-chemotherapeutic immunomodulatory drug, combined with anti-CD20 antibodies. This combination of lenalidomide with rituximab showed similar efficacy to chemoimmunotherapy (CIT) in first-line patients requiring therapy, and is approved in relapsed/refractory FL. We review the biology supporting the rationale for adequate inhibitory receptor/ligand pathways targeting the tissue immune microenvironment of FL cells, and potential immunomodulating combinations to replace CIT in the near future.

Engineering therapeutic bispecific antibodies using CrossMab technology

Bispecific antibodies have recently gained major interest as they allow novel mechanisms-of-action and/or therapeutic applications that cannot be achieved using conventional IgG-based antibodies. A major issue in engineering IgG-based bispecific antibodies has been to enable the correct association of heavy and light chains resulting in correct assembly of the desired bispecific antibody in sufficient yield. Various approaches have been described during recent years to tackle this challenge. We have developed the so-called CrossMab technology that enforces correct light chain association based on the domain crossover of immunoglobulin domains in the Fab region of the bispecific antibody. This versatile technology allows the generation of different bispecific antibody formats including asymmetric heterodimeric monovalent 1 + 1 bispecific antibodies and asymmetric heterodimeric bispecific antibodies with 2 + 1 valency in combination with approaches enabling Fc-hetermodimerization like knob-into-hole technology as well as the generation of tetravalent symmetric bispecific antibodies with 2 + 2 valency, also known as Tandem-Fab based IgG antibodies, using processes suitable for the large scale production of therapeutic bispecific antibodies. Notably, as of now, at least eight different bispecific antibodies using CrossMab technology entered clinical development, and additional CrossMabs are in late preclinical development. This review provides a summary of the status and progress with the engineering and generation of CrossMab technology based bispecific antibodies as well as their therapeutic application.

The promising role of monoclonal antibodies for immunotherapy of the HIV-associated cancer, non-Hodgkin lymphoma

Association between HIV/AIDS and some of the cancers such as lymphomais is well known. Relative risk for developing non-Hodgkin lymphoma (NHL) increases 60-200 folds in HIV-infected individuals. Diffuse large B cell lymphoma (DLBCL), primary effusion lymphoma (PEL), Burkitt's lymphoma (BL) and Plasmablastic Lymphoma (PBL) are among the most frequent subtypes. During the last century, scientists found that the immune system could potentially detect and destroy cancer cells. Therefore, they started a new field of study, which is named immunotherapy. There are different immunotherapeutic methods, among which therapeutic antibodies, such as Brentuximabvedotin (Adcetris), Ibritumomabtiuxetan (Zevalin) and rituximab (Rituxan), used for treatment of NHLs showed promising results. In this article, we will review the immunotherapeutic option, monoclonal antibodies, for treatment of HIV-associated NHLs as well as their recent clinical status. We will also discuss the selective monoclonal antibody for each subtype of NHLs.