Innovative Bispecific Nanobody Targeting PDCD1 and TNFRSF9 for Advanced Colon Cancer Immunotherapy

VHH-P375 is an advanced, humanized nanobody-based therapeutic selectively targeting programmed cell death 1 (PDCD1) and TNF receptor superfamily member 9 (TNFRSF9). Currently in the Biological Testing stage, VHH-P375 has been engineered as a bispecific fusion antibody to enhance immune modulation against colon cancer. By engaging both PDCD1 and TNFRSF9, VHH-P375 offers a novel mechanism to potentially overcome resistance seen with current immunotherapies. Its design strategically leverages the unique roles of PDCD1 and TNFRSF9 in tumor-induced immune evasion, representing a promising direction for the treatment of colon cancer.

Licensing Opportunity

VHH-P375 is available for out-licensing and collaborative partnerships. We welcome inquiries from industry and academic partners interested in advancing this innovative immunotherapy program for colon cancer.

Development Phase

Modality

VHH-P375 is a conditionally-active, bispecific nanobody fusion construct comprised of two polypeptide chains. Each chain features a masking moiety that is cleavable by matrix metalloproteinase 9, unveiling an agonistic nanobody directed at 4-1BB. The fusion protein also includes a human IgG1 Fc domain with LALA mutations to minimize undesired effector function and a binding fragment specific for PDCD1. Expressed in mammalian host cells, the structure utilizes the small size and high solubility of nanobodies for superior tumor penetration and stability. These features are expected to maximize immune activation within the tumor microenvironment while reducing off-tumor effects, thus offering new opportunities to address the challenges in colon cancer therapy.

Target

VHH-P375 is designed to engage two critical immuno-oncology targets: PDCD1 and TNFRSF9. PDCD1 is an inhibitory receptor predominantly expressed on activated T cells, playing a central role in downregulating immune responses. TNFRSF9 is expressed on various immune subsets, notably activated T cells and natural killer cells, mediating costimulatory signaling that enhances immune cell proliferation and function. In the context of colon cancer, tumor cells exploit PDCD1 pathways to evade immune surveillance, while TNFRSF9-driven signaling can dramatically boost anti-tumor immunity. The dual targeting of PDCD1 and TNFRSF9 positions VHH-P375 as a powerful immunotherapeutic agent, offering strategic advantages over monospecific approaches and addressing key mechanisms of immune escape in colon cancer.

Mechanism of Action

VHH-P375 mediates its anti-tumor effects through simultaneous modulation of PDCD1 and TNFRSF9. By antagonizing PDCD1, it disrupts immune checkpoint-mediated inhibition of effector T cells, promoting robust anti-tumor responses. Concurrently, the agonistic engagement of TNFRSF9 delivers co-stimulatory signals critical for T cell activation, proliferation, and survival. This synergistic mechanism aims to enhance both the initiation and persistence of immune-mediated tumor cell killing. The conditional activation and bispecificity of VHH-P375 reflect the versatility of the nanobody platform, supporting potential applications in developing antibody-drug conjugates or multi-specific immunotherapies tailored for complex immuno-oncology challenges.

Colon Cancer

Colon cancer, a leading cause of cancer morbidity and mortality worldwide, is characterized by the malignant transformation of epithelial cells within the colon. Its incidence is increasing in many regions, placing a significant burden on healthcare systems. Mainstay treatments include surgical resection, chemotherapy, radiotherapy, and targeted therapies that modulate key oncogenic signaling pathways. Despite advancements, late-stage or metastatic disease remains difficult to treat, with limited durable responses and frequent relapse due to intrinsic and acquired resistance. Immunotherapy has reshaped the therapeutic landscape for some cancers, but only a fraction of colon cancer patients achieve lasting benefit from current immune checkpoint inhibitors. There remains a critical unmet need for therapies that can overcome immune evasion strategies and improve overall survival. By simultaneously targeting PDCD1 and TNFRSF9, VHH-P375 represents a promising new approach that could activate immune responses more effectively within the tumor microenvironment, positioning it as a potentially transformative option for colon cancer patients with limited treatment alternatives.