Therapeutic Antibodies

Antibodies are complex proteins naturally generated by the immune system to neutralize foreign pathogens such as bacteria or viruses. B cells, a white blood cell type responsible for the generation of antibodies in response to pathogens, secrete billions of antibodies with different specificities into the bloodstream. Antibodies are structurally distinct Y-shaped proteins formed through the combination of two long proteins, called heavy chains, and two short proteins, called light chains. Each heavy and light chain pair forms a binding site where the antibody specifically binds its target, otherwise known as an antigen, at the Fab domain of the antibody molecule.

The specificity of each antibody to a target, and the potency of its binding strength to that target are defined by the amino acid sequences of heavy and light chains in the Fab domain of the antibody molecule. The other end of the antibody, called the Fc domain, is responsible for communication between the antibody and the rest of the immune system. Fc domains bind to various receptors and cause immune system effector responses.

Therapeutic antibodies are typically non-naturally occurring, or recombinant, antibodies specifically developed to treat human diseases by binding to certain proteins, and thereby modulating key biological processes. Therapeutic antibodies are injectable products that are typically dosed subcutaneously or intravenously.

Somatic Hypermutation

Our innovative platform is designed to replicate the natural process of somatic hypermutation (SHM) embedded within the human immune system to rapidly develop a diverse range of therapeutic-grade antibodies in vitro. SHM is a critical, endogenous process that generates the essential antibody diversity required to develop a natural immune response to pathogens. Our genomes encode a limited number of antibody genes, which are insufficient to generate antibodies against the wide variety of foreign pathogens encountered from the external environment. SHM enables our immune system to expand the limited diversity encoded within our genomes to the billions of antibody specificities required to defend ourselves against external pathogens.

The key enzyme required for SHM is called activation-induced cytidine deaminase, or AID. AID has been genetically conserved throughout mammalian biology and is required for the non-random mutagenesis pattern associated with SHM. AID is specifically expressed by B cells after contact with a foreign pathogen and modifies antibody sequences in a non-random fashion. Through SHM, B cells evolve antibodies with the potency and specificity required to clear the foreign pathogen. However, within the in vivo environment, SHM does not generally progress to the creation of high potency antibodies or develop antibodies against the body’s own proteins.

SHM Platform

By coupling in vitro SHM with our mammalian cell system that simultaneously displays and secretes antibodies, we believe our SHM platform is able to rapidly identify and mature antibodies with desired functional activity to high potency while simultaneously mitigating the risks associated with manufacturing. We introduce AID into mammalian cells to replicate the non-random mutagenesis SHM pattern observed within B cells in vivo. Starting with a library of either fully-human or humanized antibodies, our platform generates AID-based variants of the starting antibody library throughout the process. We have demonstrated that the pattern of mutagenesis we observe in vitro using our platform technology closely mimics the pattern observed among in vivo generated antibodies, thereby increasing confidence that antibodies generated by our platform will be tolerated when used as therapeutic drugs in humans.

By selecting antibodies based on their antigen binding from the broad antibody library population our SHM platform develops, we are able to evolve in an iterative fashion the binding potency and function of antibodies to levels that we believe will be required for therapeutic use. We believe this approach allows us to rapidly generate antibodies with high binding potency against a target. Through this approach, we have successfully generated therapeutic antibody product candidates to more than 25 targets, including targets that have been challenging for competing antibody technology platforms.

Each evolving antibody is expressed within the SHM-active mammalian cell to concurrently (i) display the evolved antibody on the cell surface to permit cell sorting selection for potency properties while (ii) the same antibody is secreted into the extracellular media at sufficient quantities to permit functional assays to be conducted. In this manner, the evolving antibodies expressed by each transfected cell are assessed in a high-throughput fashion for the desired functional activity relevant to the therapeutic mechanism.

To access scientific publications on this topic, please click here.

Key Advantages

We believe our SHM platform has the following advantages over competing approaches:

Diversity Against Difficult Targets
We are able to generate an unprecedented diversity of antibodies by applying SHM-based diversification outside of the constraints of an in vivo environment. This enables us to develop antibodies against human targets that we believe have not otherwise been accessible to prior technologies.

High Potency
Because our platform generates highly-potent antibodies, we are potentially able to modulate every extracellular target associated with human disease, and believe only small therapeutic doses may be required to mediate therapeutic effect in vivo.

Functional Activity Selection
Our mammalian cell system simultaneously displays and secretes antibodies during the antibody discovery process, allowing us to incorporate functional assays throughout the process and focus on producing product candidates that are optimized for the desired therapeutic activity.

Speed
Our platform technology enables us to generate therapeutic-grade antibodies and initiate subsequent preclinical manufacturing and toxicology studies.

Manufacturability
By utilizing our mammalian cell display system, we believe our approach increases the probability of success in manufacturing and commercialization by mitigating risks associated with antibody expression, formulation and stability.

Publications

Technology Platform

Coupling mammalian cell surface display with somatic hypermutation for the discovery and maturation of human antibodies

Bowers et al. Proc Natl Acad Sci U S A. 2011 Dec 20;108(51):20455-60. doi:10.1073/pnas.1114010108

Mammalian cell display for the discovery and optimization of antibody therapeutics

Bowers et al. Methods. 2014 Jan 1;65(1):44-56. doi:10.1016/j.ymeth.2013.06.010

The Biochemistry of Somatic Hypermutation

Peled et al. Annu Rev Immunol. J Exp Med. 2005 May 2;201(9):1467-78. doi:10.1146/annurev.immunol.26.021607.090236

Intricate targeting of immunoglobulin somatic hypermutation maximizes the efficiency of affinity maturation

Zheng et al. J Exp Med. 2005 May 2;201(9):1467-78. doi:10.1084/jem.20042483

Generation and iterative affinity maturation of antibodies in vitro using hypermutating B-cell lines

Cumbers et al. Nat Biotechnol. 2002 Nov;20(11):1129-34. doi:10.1038/nbt752

ANB020

Proof-of-Concept Phase-2a Clinical Trial of ANB020 (Anti-IL-33 Antibody) in the Treatment of Moderate-to-Severe Adult Atopic Dermatitis

Ogg et al. 2018 May. Presented at the 2018 European Academy of Allergy and Clinical Immunology (EAACI) Congress.

Proof-of-Concept Phase-2a Clinical Trial of ANB020 (Anti-IL-33 Antibody) in the Treatment of Moderate-to-Severe Adult Atopic Dermatitis

Ogg et al. 2018 Feb. Presented at the 2018 American Academy of Dermatology (AAD) Annual Meeting.

A Phase 1 Study of ANB020, an Anti-IL-33 Monoclonal Antibody, in Healthy Volunteers

Kenney et al. 2017 Mar. Presented at the 2017 American Academy of Dermatology (AAD) Annual Meeting and the American Academy of Allergy, Asthma and Immunology (AAAAI) 2017 Annual Meeting.

Peanut Allergy Translational Research Study

Garabatos et al. 2017 Mar. Presented by the Benaroya Research Institute at the American Academy of Allergy, Asthma and Immunology (AAAAI) 2017 Annual Meeting.

A rare IL33 loss-of-function mutation reduces blood eosinophil counts and protects from asthma

Smith et al. PLoS Genet. 2017 Mar 8;13(3):e1006659. doi: 10.1371/journal.pgen.1006659

IL-33: an alarmin cytokine with crucial roles in innate immunity, inflammation and allergy

Cayrol et al. Curr Opin Immunol. 2014 Dec;31:31-7. doi:10.1016/j.coi.2014.09.004

Resolution of Allergic Inflammation and Airway Hyperreactivity Is Dependent upon Disruption of the T1/ST2–IL-33 Pathway

Kearley et al. Am J Respir Crit Care Med. 2009 May 1;179(9):772-81. doi:10.1164/rccm.200805-666OC

Anti-IL-33 antibody treatment inhibits airway inflammation in a murine model of allergic asthma

Liu et al. Biochem Biophys Res Commun. 2009 Aug 14;386(1):181-5. doi:10.1016/j.bbrc.2009.06.008

Decoding asthma: Translating genetic variation in IL33 and IL1RL1 into disease pathophysiology

Grotenboer et al. J Allergy Clin Immunol. 2013 Mar;131(3):856-65. doi:10.1016/j.jaci.2012.11.028

Functional analysis of protective IL1RL1 variants associated with asthma risk

Ramirez-Carrozzi et al. J Allergy Clin Immunol. 2015 Apr;135(4):1080-3.e3. doi:10.1016/j.jaci.2014.10.028

ANB019

A Phase 1 Study of ANB019, an Anti-Interleukin-36-Receptor (IL-36R) Monoclonal Antibody, in Healthy Volunteers

Khanskaya et al. 2018 May. Poster presented at the 2018 European Academy of Allergy and Clinical Immunology (EAACI) Congress.

IL-36 in psoriasis

Towne et al. Curr Opin Pharmacol. 2012 Aug;12(4):486-90. doi:10.1016/j.coph.2012.02.009

IL-36: a potential psoriasis target?

Raison et al. Expert Rev Dermatol. 2012 7(6):503-505. doi:10.1586/EDM.12.65

Interleukin-36–Receptor Antagonist Deficiency and Generalized Pustular Psoriasis

Marrakchi et al. N Engl J Med. 2011 Aug 18;365(7):620-8. doi:10.1056/NEJMoa1013068

Mutations in IL36RN/IL1F5 Are Associated with the Severe Episodic Inflammatory Skin Disease Known as Generalized Pustular Psoriasis

Onoufriadis et al. Am J Hum Genet. 2011 Sep 9;89(3):432-7. doi:10.1016/j.ajhg.2011.07.022

Opposing activities of two novel members of the IL-1 ligand family regulate skin inflammation

Blumberg et al. J Exp Med. 2007 Oct 29;204(11):2603-14. doi:10.1084/jem.20070157

Immuno-Oncology

Identification and characterization of TSR-042, a novel anti-PD-1 therapeutic antibody

Laken et al. Poster presented at EORTC-NCI-AACR Symposium on Molecular Targets and Cancer Therapeutics 2016.

Discovery of TSR-022, a novel, potent anti-TIM-3 therapeutic antibody

Laken et al. Poster presented at EORTC-NCI-AACR Symposium on Molecular Targets and Cancer Therapeutics 2016.

Targeting PD-1, TIM-3 and LAG-3 in Combination for Improved Immunotherapy Combinations

Kehry et al. Poster presented at AACR Annual Meeting 2015.

Generation of anti-LAG-3 monoclonal antibodies for use in immunotherapy combinations

Jun et al. Poster presented at Keystone Symposium on Antibodies as Drugs 2015.

Identification and Characterization of a Potent Anti-Human Tim-3 Antagonist

Correia et al. Poster presented at AACR Special Conference on Tumor Immunology and Immunotherapy 2014.