The field of antibody-drug conjugates (ADCs) and bispecific antibody-drug conjugates (bsADCs) is rapidly expanding, offering new hope for the treatment of a range of solid tumors with high unmet medical need. Recent abstracts from the annual meeting of the American Association for Cancer Research (AACR), held April 17 – 22, 2026, in San Diego, CA, highlight several promising technological and therapeutic advances with Biocytogen’s RenLite® transgenic mouse platform and proprietary linker/payload technologies at the forefront.
A new era in cancer therapy
Bispecific antibody-drug conjugates (bsADCs) targeting dual tumor-associated antigens (TAAs) are ushering in a new era in cancer therapy. By engaging two different TAAs simultaneously, bsADCs can overcome drug resistance, increase tumor specificity, boost internalization for more effective tumor killing, and provide stronger, longer-lasting effects in heterogeneous tumors. The AACR 2026 Annual Meeting showcased significant advances in this field, with Biocytogen’s innovative RenLite® platform
RenLite-derived common light chain antibodies are highly developable and easy to assemble into bispecific antibodies (BsAbs) with a low mismatch rate and strong physiochemical properties. Coupled with a target gene knockout strategy, RenLite KO mice can produce antibodies with increased diversity, potentially recognizing novel epitopes and exhibiting cross-species reactivity.
Proprietary Linker/Payload System – BLD1102
- BLD1102 is Biocytogen’s independently developed ADC platform, built around BCPT02, a novel topoisomerase I inhibitor with broad-spectrum and potent tumor-killing activity.
- The cleavable linker design is highly hydrophilic, making BLD1102-ADCs as hydrophilic as monoclonal antibodies, which greatly enhances their physiochemical properties and plasma stability.
- BLD1102-ADCs have demonstrated more potent tumor-killing compared with standard vcMMAE-based ADCs and good tolerability in preclinical non-human primate studies.
Rapid Generation and Screening
The RenLite platform enables rapid assembly and high-throughput screening of high-quality BsAbs/BsADCs in both in vitro and in vivo systems. As part of Project Integrum, combinations of TAA-targeting antibodies generated from RenLite mice are systematically evaluated for pharmacologic efficacy and translational potential, using large-animal models to further prioritize candidates for clinical development.
Accelerating Fully Human BsAb and BsADC Discovery
RenLite transgenic mice enable the rapid generation of fully human antibody candidates with a common light chain, addressing key pain points in BsAb and BsADC development, such as heavy-light chain mismatch, poor toxicity control, and manufacturing complexity. This platform supports flexible pairing, rapid screening, and robust validation of target synergy, with a library covering over 200 tumor-associated antigens. [1]
Preclinical candidates developed using RenLite® include DM001 (anti-TROP2×EGFR) and DM005 (anti-EGFR×MET), both of which demonstrate potent tumor-suppressive activity and strong anti-tumor efficacy across multiple patient-derived xenograft (PDX) models. The RenLite® approach is accelerating the translation of BsAb and BsADC concepts from discovery to clinical development.[1]
BCG039: Nectin-4×TROP2 Bispecific ADC in Urothelial Carcinoma and Beyond
BCG039 is a bispecific ADC targeting Nectin-4 and TROP2, two clinically validated antigens in metastatic urothelial carcinoma (mUC). Developed using the RenLite® platform, BCG039 demonstrated superior tumor growth inhibition and anti-tumor efficacy in preclinical models compared to the respective single-target ADCs, with cooperative arm interactions enhancing internalization and cytotoxicity. BCG039 includes Biocytogen’s proprietary linker-payload, BLD1102 with an drug-to-antibody ratio of approximately 4. [2]
These findings suggest that BCG039 may not only improve efficacy but also reduce toxicity relative to single-targeting ADCs, making it a promising candidate now advancing through chemistry, manufacturing, and controls (CMC) development for further clinical studies.[2]
BCG015: First-in-Class ADC Targeting TM4SF5 for Hepatocellular Carcinoma
Hepatocellular carcinoma (HCC) remains a leading cause of cancer mortality, with limited effective therapies. BCG015, a novel ADC targeting TM4SF5—expressed in 70% of HCC samples but with limited expression in normal tissues—showed strong in vitro and in vivo tumor growth inhibition, with efficacy comparable or superior to ADCs targeting other HCC antigens.[3]
The anti-TM4SF5 antibody, generated with RenLite® mice, exhibited high affinity, specificity, and robust internalization, and BCG015 demonstrated good stability and physicochemical properties. Early safety studies are ongoing, with BCG015 representing a first-in-class, promising therapeutic option for HCC patients with TM4SF5 expression.[3]
BCG026: FAP×GPC1 Bispecific ADC for Stromal and Tumor Targeting in Pancreatic and Other Solid Tumors
Pancreatic adenocarcinoma (PAAD) is distinguished by its dense, fibrotic, and highly treatment-resistant stroma, which drives rapid disease progression and contributes to poor clinical outcomes. This stroma is primarily composed of cancer-associated fibroblasts (CAFs), which accumulate within tumors and secrete collagen and fibronectin, leading to extensive remodeling of the extracellular matrix.
CAFs also intensify the desmoplastic response, promoting early tumor invasion, high recurrence rates, and persistent resistance to conventional therapies. Fibroblast activation protein (FAP) is a highly specific marker of CAFs and is expressed in the majority of human epithelial cancers. Glypican-1 (GPC1), another critical factor, is aberrantly overexpressed in PAAD and is found at elevated levels in colorectal, prostate, and breast cancers. Together, these characteristics make CAFs and their associated proteins compelling therapeutic targets in PAAD and other solid tumors.
BCG026 is a bispecific antibody-drug conjugate (ADC) designed to simultaneously target FAP on CAFs and GPC1 on tumor cells—both highly expressed in PAAD and a variety of epithelial cancers. This dual-targeting bsADC demonstrates strong binding affinity for both antigens, efficient internalization, and a CAF-dependent bystander killing effect.
In preclinical studies, BCG026 exhibited robust antitumor activity and synergistic effects superior to those observed with single-target ADCs. By addressing both stromal and tumor cell compartments, this innovative strategy has the potential to overcome barriers posed by the tumor microenvironment and cellular heterogeneity, representing a promising new therapeutic approach for PAAD and other solid tumors. Ongoing studies continue to evaluate its efficacy and translational potential.[4]
Next steps
Emerging data presented at AACR 2026 highlight the transformative potential of bispecific ADCs. These abstracts underscore the rapid progress in bispecific and novel ADC development, with platforms like RenLite® enabling more efficient generation of fully human, developable candidates. Bispecific ADCs such as BCG039 and BCG026, as well as first-in-class agents like BCG015, are showing superior efficacy and promising safety profiles in preclinical models, paving the way for future clinical translation and the potential to address major unmet needs in cancer therapy.
References
[1] Hsu J, Zhang W, Du J, et al. RenLite® transgenic mice provide a high-quality platform for accelerating the development of fully human bispecific antibodies or ADCs worldwide. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl): Abstract nr 1681.
[2] An F, Yang L, Shang C, et al. Preclinical study of BCG039, a Nectin-4×TROP2 bispecific ADC, in urothelial carcinoma and other solid tumor models. Frank An, Liu Yang, Chengzhang Shang, Junlan Han, Yi Yang, Frank An. Preclinical study of BCG039, a Nectin-4×TROP2 bispecific ADC, in urothelial carcinoma and other solid tumor models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl): Abstract nr 1720.
[3] Wang G, Qi Z, Qi Y, et al. BCG015:A first-in-class antibody-drug conjugate targeting TM4SF5 for the treatment of hepatocellular carcinoma. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl): Abstract nr 1657.
[4] Wei H, Zhang N, Hao K, et al. BCG026: FAP × GPC1 bispecific ADC – A novel targeting approach for stromal and tumor cells in pancreatic cancer and other solid tumors. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl): Abstract 6938.
Featured image: Washington, DC – The AACR 2017 Annual Meeting. Photo courtesy © 2017 – 2026 AACR/Scott Morgan. Used with permission.
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