you may also like

    BLD1102: Novel Linker–Payload System for Potent, Highly Stable Bispecific ADCs

    BLD1102: Novel Linker–Payload System for Potent, Highly Stable Bispecific ADCs

    December 10, 2025
    Share on:

    Antibody–drug conjugates (ADCs) are a leading cancer therapy, delivering cytotoxic payloads with improved tumor specificity, yet off-target effects and resistance—particularly in solid tumors—continue to limit efficacy. Bispecific ADCs (BsADCs) help address these challenges through dual-epitope or dual-target engagement, improving tumor selectivity, internalization, and potency. With 10+ candidates now in clinical development, BsADCs are advancing rapidly, but optimal performance still depends on coordinated co-optimization of the antibody, linker, and payload (Fu et al. 2023).

     

    Antibody–Drug Conjugates (ADCs)'s 3D Structure

    ADC Structure, Key Features, and Core Mechanism of Action

    ADC Structure, Key Features, and Core Mechanism of Action (Fu et al. 2023)

     

     

     

    Biocytogen’s Bispecific ADC Platform

    Our BsADC platform brings these elements together by combining the RenLite®  fully human common light chain platform with the BLD1102 novel linker–payload system, empowering high-diversity antibody discovery, efficient bispecific assembly, and superior ADC performance.

    Biocytogen’s BsADC Platform

    ▷ Key Advantages of Biocytogen’s BsADC Platform

    • Fully human common light chain antibodies assemble efficiently into bispecifics with low mismatch rates and favorable physicochemical properties.
    • RenLite KO mice expand antibody diversity, enabling recognition of novel or conserved epitopes and broad cross-species reactivity.
    • BLD1102 novel linker–payload system provides high hydrophilicity, optimized enzymatic cleavage, and potent DNA-damaging activity.
    • High-throughput in vitro and in vivo screening accelerates the generation and selection of high-quality bsAbs and bsADCs. 

     

    ▷ BLD1102: Biocytogen’s Proprietary Novel Linker–Payload System

    • BCPT02 payload: A novel topoisomerase I inhibitor with broad, potent antitumor activity.
    • Cleavable linker with excellent hydrophilicity: Enhances ADC stability and physicochemical properties, making ADCs as hydrophilic as monoclonal antibodies.
    • BLD1102-ADCs demonstrated stronger antitumor efficacy than vcMMAE and excellent stability in plasma.
    • BLD1102-ADCs demonstrated good tolerability in non-human primate studies.
    • Independently developed and fully owned by Biocytogen.

     

     

    Discovery of Novel BsADCs

    As part of Project Integrum, tumor-associated antigen (TAA)–targeting antibodies derived from RenLite® or RenLite KO mice are assembled into fully human common light chain bispecifics. BsADC candidates conjugated with BLD1102 undergo rigorous in vitro functional and developability assessments, followed by in vivo efficacy, PK/PD, and toxicity studies. Our large-animal translational platform further identifies bsADC candidates with optimal clinical potential.

    Preclinical-Stage ADC Assets (Partial List)

     

    Ready to accelerate your next-generation bispecific ADC development? Connect with our team to explore co-development, licensing, or custom discovery partnerships powered by RenLite® and BLD1102!
     
     

    Case Study: Fully Human Common Light Chain DLL3 × B7-H3 BsADC

    DLL3 is highly restricted to SCLC, neuroendocrine tumors, and glioblastoma, with minimal or no expression in normal tissues. B7-H3 is overexpressed across multiple tumor types, including SCLC. Both are well-validated therapeutic targets for SCLC.

    Biocytogen generated DLL3 × B7-H3 BsADCs using a fully human common light chain bispecific format, paired with the highly hydrophilic, enzyme-cleavable BLD1102 linker and a novel TOP1 inhibitor payload capable of delivering a potent bystander effect.

    In vitro and in vivo characterization (DLL3 × B7-H3 BsADC Poster)

    • High affinity for human DLL3 and B7-H3 (~100 pM)
    • Superior internalization compared to benchmark antibodies
    • Strong antitumor efficacy in vitro and in vivo
    • Excellent developability under stress conditions

     

    Frequently Asked Questions (FAQs)

    1: What makes bispecific ADCs different from traditional ADCs?

    BsADCs target two epitopes or antigens instead of one, improving tumor selectivity, internalization, and antitumor potency. This dual-target design helps address challenges such as off-target toxicity and tumor resistance seen with traditional ADCs.

    2: How does the BLD1102 linker–payload system improve ADC performance?

    BLD1102 pairs a novel TOP1 inhibitor with a hydrophilic, cleavable linker to enhance ADC stability, solubility, and controlled payload release. Preclinical data show stronger efficacy than vcMMAE and good tolerability, improving overall ADC performance.

    3: What are the advantages of using RenLite® mice for bispecific antibody discovery?

    RenLite® mice generate fully human common light chain antibodies, enabling efficient bispecific assembly with low mismatch rates. Combined with RenLite KO, the platform expands diversity and supports discovery of novel or conserved epitopes for high-quality BsADCs.

     

    Reference:

    Fu, Zhiwen, et al. "Antibody drug conjugate: the “biological missile” for targeted cancer therapy." Signal transduction and targeted therapy 7.1 (2022): 93.