Beijing-based Huahui Health has initiated a first-in-human trial of HH160, a potential first-in-class trispecific antibody engineered to block PD-1, CTLA-4, and VEGF-A within a single molecule. The trial's relevance lies in whether simultaneous triple blockade — combining dual checkpoint inhibition with anti-angiogenic activity in one construct — can improve on the toxicity and efficacy profile of combining three separate agents, a question that has grown more pressing as PD-1/CTLA-4 combinations become standard of care in several tumor types. BeOne Medicines (Nasdaq: ONC), which agreed in April 2026 to pay USD 20 million upfront for a global exclusive option to license HH160 in a deal valued at up to approximately USD 2.02 billion, is listed as a collaborator and study director.
The Phase I study (NCT07623369) follows a two-part sequential design, with Part 1 consisting of dose escalation across patients with advanced solid tumors to establish the maximum tolerated dose, and Part 2 a safety expansion cohort in selected tumor types. The specific tumor types include non-small cell lung cancer (NSCLC), hepatocellular carcinoma, colorectal cancer, and additional indications to be determined by emerging data. HH160 is administered by intravenous infusion every three weeks. The trial is open-label and non-randomized, according to the trial record.
Enrollment is planned for approximately 56 participants with eligible tumor types spanning a broad range of solid malignancies, including gastroesophageal adenocarcinoma, head and neck squamous cell carcinoma, renal cell carcinoma, endometrial carcinoma, cervical cancer, ovarian cancer, small cell lung cancer, triple-negative breast cancer, and urothelial carcinoma. Patients with active leptomeningeal disease, uncontrolled brain metastases, or significant bleeding risk are excluded. Primary completion is expected by August 2028.
HH160's hexavalent architecture with silent Fc
HH160 was constructed by fusing anti-PD-1 and anti-CTLA-4 nanobodies to the N- and C-termini of the heavy chain of an anti-VEGF-A human IgG1 antibody, forming a symmetrical hexavalent molecule with two binding sites per target, according to a preclinical abstract presented at the AACR Annual Meeting (Cancer Research, 2025). The Fc region is silenced — attenuating effector functions — a design choice that in the checkpoint inhibitor field is generally employed to prevent Fc-mediated depletion of PD-1- or CTLA-4-expressing T cells.
The use of nanobody-based domains for the checkpoint arms is mechanistically notable. Nanobodies, derived from single-domain camelid antibody fragments, are substantially smaller than conventional Fab regions, enabling a more compact and potentially more manufacturable multi-specific architecture. The anti-VEGF-A conventional IgG1 backbone provides the structural scaffold. Huahui Health developed HH160 on its proprietary PolyBoost multispecific antibody platform, which the company describes as enabling this type of multi-arm construction.