Hot off its first FDA approval, Day One Biopharmaceuticals added a new early-stage programme to its oncology pipeline on Tuesday, hopping into the much-hyped antibody-drug conjugate (ADC) space. For more analysis on deals involving the modality, see Vital Signs: Tracking the new converts to ADCs. The California-based biotech licensed ex-China rights to MTX-13, a PTK7-targeting ADC, from MabCare Therapeutics. Day One will rename the candidate DAY301 and plans to start a Phase I trial in solid tumours by the first quarter of 2025. The Chinese firm will receive $55 million upfront and is eligible for up to $1.15 billion in development, regulatory and commercial milestones, plus low-to-mid single-digit royalties.
Day One is betting on a less-well-known target for its first ADC. According to the company, PTK7 is a catalytically inactive transmembrane protein that is overexpressed in multiple solid tumours and underexpressed in healthy tissues. Samuel Blackman, Day One’s head of R&D, said that the company believes “the linker-payload technology embodied in DAY301 will overcome the limitations of earlier PTK7-targeted ADCs, giving us a potential first-in-class drug against a clinically-validated target.”