A Next-Generation Trispecific Nanobody Engager Targeting CLEC12A and FCGR3A for Advanced Cancer Immunotherapy

VHH-P666 is a trispecific humanized nanobody antibody engineered to target both C-type lectin domain family 12 member A (CLEC12A) and Fc gamma receptor IIIa (FCGR3A). Currently in the Biological Testing phase, VHH-P666 incorporates a modular architecture fusing camelid-derived single-domain antibodies to maximize affinity and specificity for these two clinically relevant antigens. This innovative platform is designed for the potential treatment of cancer, leveraging dual-targeting and immune cell engagement to enhance anti-tumor activity. By addressing both CLEC12A and FCGR3A, VHH-P666 stands to provide a differentiated approach in immuno-oncology drug development.

Licensing Opportunity

VHH-P666 is available for out-licensing and collaborative partnerships. We welcome inquiries from biopharmaceutical companies and research institutions seeking innovative immuno-oncology assets targeting CLEC12A and FCGR3A. Engage with us to advance VHH-P666 towards clinical and commercial success.

Development Phase

Modality

VHH-P666 utilizes a state-of-the-art trispecific construct composed of humanized camelid single-domain antibodies (VHH) that recognize CD16 and CLEC12A, fused via engineered peptide linkers to a human interleukin 15 fragment, all expressed in Expi293 cells. The unique nanobody format, characterized by its small molecular size and high stability, facilitates superior tumor tissue penetration and robust resistance to denaturation compared to conventional antibodies. This structure grants VHH-P666 the ability to simultaneously target cancer cells and potentiate immune cell responses. The modular design of VHH-P666 holds significant advantages for cancer therapy, offering precise targeting with improved safety and manufacturability.

Target

CLEC12A and FCGR3A are well-characterized cell surface proteins that have emerged as promising immunotherapeutic targets for cancer. CLEC12A is a transmembrane receptor mainly expressed on myeloid lineage cells, particularly in acute myeloid leukemia, while sparing most healthy hematopoietic cells. FCGR3A, an immunoglobulin Fc receptor, is predominantly found on natural killer (NK) cells and some myeloid cells, where it mediates antibody-dependent cytotoxicity. The dual targeting of CLEC12A and FCGR3A allows VHH-P666 to address malignant cells while simultaneously engaging and activating effector immune cells. Targeting CLEC12A disrupts cancer cell survival, and FCGR3A engagement mobilizes innate immune responses, providing a synergistic benefit. As a result, VHH-P666 holds strong strategic value for next-generation cancer immunotherapy pipelines focused on these validated antigens.

Mechanism of Action

VHH-P666 exerts its anti-cancer effects via trispecific engagement of key immune effector and malignant cell populations. By binding to CLEC12A on cancer cells and FCGR3A on NK cells, VHH-P666 functions as a potent cell engager, bringing immune cells into proximity with tumor targets and triggering cytotoxic activity through antibody-dependent cell-mediated cytotoxicity (ADCC) and subsequent signal transduction cascades. The inclusion of an interleukin 15 module aims to further enhance immune effector cell proliferation and persistence in the tumor microenvironment. This modular nanobody platform not only demonstrates the capacity for multi-specific engagement but also establishes a blueprint for further development into formats such as antibody-drug conjugates (ADC) or bispecific antibodies, leveraging the inherent flexibility and favorable manufacturability of nanobodies.

Cancer

Cancer remains one of the leading causes of morbidity and mortality worldwide, with millions of new cases diagnosed annually across all major organ systems. Despite advances in conventional therapies such as surgery, chemotherapy, radiation, and targeted agents, many patients face limited efficacy and significant adverse effects. Targeted immuno-oncology approaches, including immune checkpoint inhibitors and cell therapy, have ushered in a new era, yet significant obstacles such as tumor resistance, immune evasion, and restricted drug penetration persist. In particular, hematologic malignancies and solid tumors expressing CLEC12A or those susceptible to NK-cell-mediated killing present enduring treatment challenges. VHH-P666, by simultaneously engaging tumor cells and immune effector cells, is positioned to address these limitations with the potential for improved specificity, immune recruitment, and better safety profiles. The dual-targeting nanobody approach may provide a new therapeutic modality to overcome resistance mechanisms and expand effective treatment options for cancer patients.