Antibodies, Volume 5, Issue 1 (March 2016) – 6 articles

Bispecific antibodies offer a promising approach for the treatment of cancer but can be challenging to engineer and manufacture. Here we report the development of PF-06671008, an extended-half-life dual-affinity re-targeting (DART^®) bispecific molecule against P-cadherin and CD3 that demonstrates antibody-like properties. Using phage display, we identified anti-P-cadherin single chain Fv (scFv) that were subsequently affinity-optimized to picomolar affinity using stringent phage selection strategies, resulting in low picomolar potency in cytotoxic T lymphocyte (CTL) killing assays in the DART format. The crystal structure of this disulfide-constrained diabody shows that it forms a novel compact structure with the two antigen binding sites separated from each other by approximately 30 Å and facing approximately 90° apart. We show here that introduction of the human Fc domain in PF-06671008 has produced a molecule with an extended half-life (-4.4 days in human FcRn knock-in mice), high stability (T_m1 > 68 °C), high expression (>1 g/L), and robust purification properties (highly pure heterodimer), all with minimal impact on potency. Finally, we demonstrate in vivo anti-tumor efficacy in a human colorectal/human peripheral blood mononuclear cell (PBMC) co-mix xenograft mouse model. These results suggest PF-06671008 is a promising new bispecific for the treatment of patients with solid tumors expressing P-cadherin. Full article

Cytokines are small, secreted, glycoproteins that specifically affect the interactions and communications between cells. Cytokines are produced transiently and locally, acting in a paracrine or autocrine manner, and they are extremely potent, ligating high affinity cell surface receptors to elicit changes in gene expression and protein synthesis in the responding cell. Cytokines produced during the differentiation of T follicular helper (Tfh) cells and B cells within the germinal center (GC) niche play an important role in ensuring that the humoral immune response is robust, whilst retaining flexibility, during the generation of affinity matured antibodies. Cytokines produced by B cells, antigen presenting cells and stromal cells are important for the differentiation of Tfh cells and Tfh cell produced cytokines act both in an autocrine fashion to firm Tfh cell differentiation and in a paracrine fashion to support the differentiation of memory B cells and plasma cells. In this review, we discuss the role of cytokines during the GC reaction with a particular focus on the influence of cytokines on Tfh cells. Full article

The association of autoantibodies to cytokines with immune deficiency, autoimmunity and/or immune dysregulation is increasingly being recognized. For example, autoantibodies to interferon gamma have been found to be associated with chronic, treatment refractory infections with intracellular organisms such as mycobacteria, autoantibodies to interleukin 17 with chronic mucocutaneous candidiasis, and anti-interferon alpha autoantibodies with systemic lupus erythematosus. While low titer autoantibodies to these and other cytokines may be detected in normal individuals, patients with infectious or autoimmune manifestations tend to have high titer autoantibodies that may block or potentiate the function of the respective cytokine. Recognition of these autoantibodies is important because it may direct treatment toward a combination of adjunctive immunotherapy to modulate the autoantibody level while continuing with appropriate anti-microbial therapy. This review focuses on the anti-cytokine autoantibodies documented to date, their autoimmune, immune dysregulation and infectious disease associations, methods for detection of these antibodies and potential treatment options. Full article

Systemic Lupus Erythematosus (SLE) is characterized by a wide spectrum of auto-antibodies which recognize several cellular components. The production of these self-reactive antibodies fluctuates during the course of the disease and the involvement of different antibody-secreting cell populations are considered highly relevant for the disease pathogenesis. These cells are developed and stimulated through different ways leading to the secretion of a variety of isotypes, affinities and idiotypes. Each of them has a particular mechanism of action binding to a specific antigen and recognized by distinct receptors. The effector responses triggered lead to a chronic tissue inflammation. DsDNA autoantibodies are the most studied as well as the first in being characterized for its pathogenic role in Lupus nephritis. However, others are of growing interest since they have been associated with other organ-specific damage, such as anti-NMDAR antibodies in neuropsychiatric clinical manifestations or anti-β2GP1 antibodies in vascular symptomatology. In this review, we describe the different auto-antibodies reported to be involved in SLE. How autoantibody isotypes and affinity-binding to their antigen might result in different pathogenic responses is also discussed. Full article

As evidenced by the recent approvals of Removab (EU, Trion Pharma) in 2009 and of Blincyto (US, Amgen) in 2014, the high potential of bispecific antibodies in the field of immuno-oncology is eliciting a renewed interest from pharmaceutical companies. Supported by rapid advances in antibody engineering and the development of several technological platforms such as Triomab or bispecific T cell engagers (BiTEs), the “bispecifics” market has increased significantly over the past decade and may occupy a pivotal space in the future. Over 30 bispecific molecules are currently in different stages of clinical trials and more than 70 in preclinical phase. This review focuses on the clinical potential of bispecific antibodies as immune effector cell engagers in the onco-immunotherapy field. We summarize current strategies targeting various immune cells and their clinical interests. Furthermore, perspectives of bispecific antibodies in future clinical developments are addressed. Full article