Next-Generation Nanobody Fusion Targeting ALB and GPRC5D for Innovative Multiple Myeloma Therapy
VHH-P639 is a humanized nanobody fusion protein specifically designed to target two clinically relevant molecules: albumin (ALB) and G protein-coupled receptor class C group 5 member D (GPRC5D). Engineered and expressed in HEK293T cells, VHH-P639 incorporates the extracellular domain of human B-cell maturation antigen, a single-chain variable fragment recognizing GPRC5D, and an anti-albumin binding domain. Currently in the Biological Testing phase, VHH-P639 demonstrates strong potential for the treatment of multiple myeloma by addressing critical targets associated with disease progression and therapeutic delivery.
| Candidate | VHH-P639 |
| Target | albumin (ALB) G protein-coupled receptor class C group 5 member D (GPRC5D) |
| Modality | humanized bispecific VHH |
| Indication | Multiple Myeloma |
Licensing Opportunity
VHH-P639 is available for out-licensing and collaborative partnerships. We welcome inquiries from potential partners and investors interested in advancing innovative therapeutics for multiple myeloma.
Contact UsDevelopment Phase
| Program | Research | Preclinical | Phase 1 |
|---|---|---|---|
| VHH-P639 |
Modality
VHH-P639 is a modular fusion protein composed of a nanobody (single-domain antibody) architecture, granting it small molecular size, enhanced tissue penetration, and high stability under diverse conditions. It features the extracellular domain of a human B-cell maturation antigen, a single-chain variable region against GPRC5D, and an anti-albumin domain, which together enable dual targeting and improved pharmacokinetics. This sophisticated structure allows VHH-P639 not only to exploit deep tumor infiltration—essential for multiple myeloma located within the bone marrow—but also to potentially extend half-life in circulation and facilitate efficient drug delivery.
Target
ALB and GPRC5D are two pivotal molecular targets in the pathogenesis and treatment of multiple myeloma. ALB, a major serum protein, plays critical roles in drug transport and systemic distribution; targeting ALB with VHH-P639 may enhance drug half-life and systemic stability. GPRC5D, a cell surface receptor, is highly expressed on myeloma cells but shows limited presence in other adult tissues, making it an attractive target for selective anti-myeloma therapies. The dual targeting of ALB and GPRC5D leverages VHH-P639’s capacity to maximize tumor selectivity, optimize bioavailability, and reduce off-target effects, thus positioning it for strategic value in multiple myeloma therapeutics development.
Mechanism of Action
VHH-P639 exerts its effect by simultaneously engaging ALB and GPRC5D. Through its binding domains, the molecule attaches to ALB, leveraging endogenous albumin’s properties to prolong systemic presence and improve tumor accumulation. Meanwhile, the specific targeting of GPRC5D interferes with cellular signaling pathways implicated in multiple myeloma cell survival and proliferation. By functioning as a signal transduction modulator, VHH-P639 disrupts pro-tumorigenic processes. The versatile nanobody scaffold also enables future development into advanced formats, such as antibody-drug conjugates (ADCs) or bispecific molecules, broadening its potential as a platform for next-generation therapeutics.
Multiple Myeloma
Multiple myeloma is a hematologic malignancy characterized by the clonal proliferation of malignant plasma cells in the bone marrow, leading to bone lesions, anemia, renal dysfunction, and immune suppression. Accounting for a significant proportion of blood cancers worldwide, multiple myeloma predominantly affects older adults and remains incurable despite advances in treatment. Current approaches include chemotherapy, immunomodulatory agents, proteasome inhibitors, and monoclonal antibodies, often combined with stem cell transplantation. However, treatment resistance, relapse, and disease heterogeneity represent major clinical challenges. There is a pressing need for innovative therapies with novel mechanisms of action and improved selectivity. VHH-P639 was specifically developed to address these unmet needs by targeting GPRC5D, a restricted antigen on myeloma cells, and leveraging ALB for enhanced delivery, offering strong promise for next-generation multiple myeloma management.