PHST677

PHST677 is a bispecific antibody-drug conjugate (ADC) being developed by Pheast Therapeutics for the treatment of various solid tumors. The therapeutic candidate is designed to target both CDH1 (E-cadherin) and Nectin-4, antigens that are frequently co-expressed in cancers such as breast, bladder, colorectal, lung, and gastric tumors. PHST677 utilizes a dual mechanism of action: it leverages CDH1-mediated macrophage-driven tumor clearance to engage the innate immune system while simultaneously utilizing Nectin-4 for selective tumor targeting and delivery of a cytotoxic payload. This combination of immune-mediated clearance and direct cytotoxic cell killing is intended to enhance anti-tumor efficacy. Preclinical data presented at the PEGS Boston Summit 2026 demonstrated selective internalization and potent activity in xenograft models of breast and bladder cancer.