Biocytogen Launches RenNano® Mouse, a Fully Human Heavy Chain Antibody Platform to Accelerate Nanobody Drug Discovery

Biocytogen Pharmaceuticals (Beijing) Co., Ltd. ("Biocytogen", HKEX: 02315) officially launched its fully human heavy chain antibody platform, RenNano®. RenNano^® is the third member of the RenMice™ family, joining RenMab™ and RenLite^®. Together, Biocytogen’s three RenMice™ platforms allow for the streamlined discovery and development of fully human monoclonal antibodies, bispecific/multispecific antibodies and single-domain antibodies (sdAbs, or nanobodies) (Figure 1).

While humans and mice generate antibodies that require heavy and light chain pairing to be functional, camels and sharks generate heavy-chain-only antibodies (HCAb), meaning their variable domains (VHH or sdAb) can function without pairing with the light chain. Owing to their nanometer-level size and small molecular weight, sdAbs have superior permeability, and thus can cross the blood-brain barrier and infiltrate solid tumor tissues. In addition, the longer CDR3 region enables sdAbs to detect the otherwise hidden epitopes of GPCRs and other challenging targets. Since sdAbs have a simple structure, they are ideal building blocks for assembling bispecific/multispecific antibodies and CAR cell therapies.

While nanobodies have its unique advantages, animals that naturally produce HCAbs, such as camels, are difficult to be widely used for the preparation of monoclonal antibodies because they are large, having a long breeding cycle and generate few offspring. Meanwhile, humanization is required to develop camelid antibody sequences into drugs, which further increases the complexity and time of drug development.

To overcome these challenges, Biocytogen engineered the RenNano^® mouse by modifying the constant region of the fully human RenMab™ model to allow for HCAb production. Compared with other existing HCAb platforms, the in situ replacement of the mouse genes with the complete human heavy chain variable genes makes the RenNano^® mouse one of the most comprehensive fully human antibody platforms in the world. SdAb sequences generated from RenNano^® mice have the highest possible diversity, and do not require antibody humanization, which saves time and cost, and reduces risk of failure during later stages of drug development. Additionally, compared with camelids or other natural HCAb-producing species, mice are easier to breed and immunize. Immunization of RenNano^® mice can generate HCAbs with diverse CDR3 sequences that recognize a variety of epitopes. These HCAbs can recognize antigens with nM-level affinity independent of light chains. Moreover, antibodies derived from RenNano^® mice are capable of exerting biological functions both in vitro and in vivo. They are highly hydrophilic and have favorable developability characteristics.

The successful development of the RenNano^® platform expands Biocytogen’s capabilities for antibody discovery and broadens the applications of our antibody library. We welcome global partners to realize the full potential of our RenMice™ platforms and derive antibodies to generate novel therapeutics.

About RenMice

RenMice™, i.e., RenMab™, RenLite^® and RenNano^® mice, which have proprietary intellectual property rights, were developed by Biocytogen over the course of 5 years using size-unlimited, precise chromosome engineering technology (SUPCE). RenMice™ is one of the top 3 fully human antibody mice made by in situ replacement technology globally. All RenMice™ members contain full human heavy chain VDJ loci replaced in situ. Regarding antibody κ light chains, RenMab™ mouse contains full human VJ loci replaced in situ and RenLite^® mouse contains a single human VJ locus replaced in situ. RenNano^® mouse has modified heavy chain constant regions to generate functional heavy-chain-only antibodies (HCAbs).

RenMice™ can generate robust immune response and produce fully human antibodies with great diversity, specificity, affinity and druggability. Using RenMice™, Biocytogen has built 6 fully human antibody discovery platforms, covering various types of targets and modalities such as monoclonal antibody (RenMab™), bispecific antibody and bispecific ADC (RenLite^®), nanobody (RenNano^®), TCR-mimic antibody for intracellular targets (HLA/RenMice, humanized RenMice™), and antibody platform against GPCR and other challenging targets (RenMice™ knockouts).

RenMice™ has been recognized by top biopharmaceutical companies around the world, including Merck KGaA, Xencor, BeiGene, and Innovent.

About Biocytogen:

Biocytogen (HKEX: 02315) is a global biotechnology company that drives the research and development of novel antibody-based drugs with innovative technologies. Using its proprietary RenMab™/RenLite^®/RenNano^® mice platforms for fully human monoclonal antibody, bispecific/multispecific antibody and nanobody development, Biocytogen has integrated its in vivo drug efficacy screening platforms and strong clinical development expertise to streamline the entire drug development process. Biocytogen is undertaking a large-scale project to develop first-in-class and/or best-in-class antibody drugs for more than 1000 targets, known as Project Integrum. This project has resulted in 28 drug co-development agreements and 16 RenMice™ licensing agreements with companies around the world, including several partnerships with multinational pharmaceutical companies (MNCs). Biocytogen's pipeline includes 12 core products, among which two products are in phase II multi-regional clinical trials and two products are in phase I. Headquartered in Beijing, Biocytogen has branches in Haimen Jiangsu, Shanghai, Boston, USA and Heidelberg, Germany. For more information, please visit http://en.biocytogen.com.cn.

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Contact information

Biocytogen’s Contacts
Antibody platforms and antibody assets: BD-Licensing@biocytogen.com
Media: pr@bbctg.com.cn