Next-Generation Antibody Therapies

We develop our therapeutic candidates using two technology platforms: our DiversImmune® platform, which we use to generate therapeutic “building blocks,” which are high affinity and high specificity antibodies with functional activity against therapeutic targets; and our MultiMabTM platform, which we use to construct therapeutic product candidates by assembling the building blocks into different combinations of bi- and multi-specific antibodies. Together, these platforms support our strategy of building a broad pipeline of next generation antibody therapeutics that are designed to address a wide range of human diseases.

DiversImmune® Antibody Discovery Platform

Our DiversImmune® platform was built to address a key bottleneck in the antibody therapeutics industry: the ability to rapidly generate high affinity and high specificity antibodies against virtually any target of interest. The DiversImmune® platform comprises three key steps, all focused on generating a diverse collection of high quality antibodies:

  1. Immunization. We have developed an integrated collection of immunization methods, termed Raptor, which includes purified proteins, engineered cells, viral-like particles, and DNA. These methods all work in concert with the goal to elicit a strong and diverse immune response.
  2. Diversification. We have developed hyperimmune mouse, along with a variety of co-stimulation methods, to optimize the immune response to each target and yield a diverse collection of antibodies that recognize different epitopes, or binding regions, on the same target protein. This is a critical component of our discovery process as we believe it greatly increases the probability of identifying antibodies with the desired functional properties necessary for therapeutic development.
  3. Optimization. We have streamlined the processes of humanization and optimization so that we can rapidly advance antibodies with the desired functional properties to fully developed building blocks. These building blocks can then be assembled into novel therapeutic product candidates using our MultiMabTM.

MultiMab Antibody Engineering Platform

Our MultiMabTM platform enables us to build a diverse array of bi- and multi-specific antibody formats, allowing us to optimize the format of our product candidates. Because biology is diverse and complex, there is no “one size fits all” solution to engineering multi-specific antibodies. Instead, different problems call for different solutions. We draw from a suite of different antibody formats to choose the one that we believe best suits the disease and mechanism we are targeting. Despite having multiple formats from which to choose, our formats typically contain two key features:

 

  • Bivalent binding. Bivalent binding, or binding with two points of contact, takes advantage of the concept of avidity, specifically that multipoint connections are much stronger than single point connections. In order to maximize efficacy, we build bivalent binding into our therapeutic product candidates where increased strength of binding is desirable. For example, ABP-102 features two identical binding sites for HER2, rather than one. This enables the molecule to bind tightly to HER2+ tumor cells, forming a strong immunological synapse, or cell-to-cell interaction, between the tumor cell and the cytotoxic T cell. We believe this is critical to generating a strong and sustained immune response and differentiates ABP-102 from other T-cell engaging bispecific antibodies that only feature a single binding site for the tumor-specific antigen.

 

  • Fc region. The Fc region of an antibody interacts with various receptors on immune cells to control both the immune response to antibody binding and the circulating half-life of an antibody. To take advantage of these natural functions, we build Fc regions into all our therapeutic product candidates. For example, ABP-102 features a human IgG1 Fc region that promotes a long circulating half-life, and has been further engineered to reduce or eliminate antibody-dependent cell-mediated cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC) to reduce potentially harmful side-effects associated with inflammation and cytokine release. Similarly, ABP-201 features an Fc region that results in greater stability and, due to its size, a longer ocular half-life, potentially enabling more convenient dosing for patients.

TetraBi Antibody Format for T-cell Engagement

We are building a pipeline of T-cell engagers based on a tetravalent bispecific (TetraBi) format. The TetraBi format of our ABP-102 candidate offers several significant advantages over other bispecific antibody formats and other approaches to T cell-based therapy.

We believe the TetraBi antibody format of our ABP-102 candidate offers several significant competitive advantages over other bispecific antibody formats and other approaches to T-cell-based therapy:

  • Enhanced potential potency through bivalent binding. By including two binding sites for the tumor antigen, our antibodies are designed to form a much stronger connection to tumor cells than competitor molecules that feature only a single binding site.
  • Potentially better dosing through inclusion of an Fc region. By including an Fc region, our TetraBi antibodies are designed to have long circulating half-lives, enabling potentially more convenient dosing for patients.
  • Controlled immune effector function through Fc engineering. By introducing defined mutations into the Fc region, we are potentially able to diminish or eliminate Fc-mediated interactions that can contribute to unwanted side effects such as CRS.
  • Lower immunogenicity. By closely resembling human antibodies with natural amino acid sequences, our TetraBi antibodies may have a reduced risk of being immunogenic, or capable of producing an undesirable immune response, which could otherwise lead to decreased efficacy.
  • Streamlined manufacturing. By building symmetrical molecules with two identical heavy chains and two identical light chains, our molecules are designed to eliminate complications arising from potential chain mispairing.
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