Day One inks $1.2B biobucks pact for MabCare’s solid tumor ADC

Day One Biopharmaceuticals is offering MabCare Therapeutics up to $1.2 billion for exclusive licensing rights to an antibody drug conjugate (ADC) taking aim at solid tumors in both adults and kids.

Day One has paid out $55 million upfront for development and commercialization rights to DAY301—originally known as MTX-13—excluding the Greater China area, where MabCare is based.

In turn, MabCare has the chance to bank an additional $1.15 billion in development and commercial milestones, plus single-digit royalties.

DAY301 is an ADC targeting protein-tyrosine kinase 7 (PTK7), which is overexpressed in esophageal, ovarian, lung and endometrial cancers among adults, as well as in neuroblastoma, rhabdomyosarcoma and osteosarcoma in children.  

The ADC nabbed investigational new drug clearance from the FDA in April, which allows for in-human testing. California-based Day One anticipates phase 1 dosing for the first patient to begin in the last quarter of this year or the first quarter of 2025.

“We believe 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,” Samuel Blackman, M.D., Ph.D., Day One co-founder and head of R&D, said in a June 18 release.

A priority for the biopharma this year is to grow its pipeline by in-licensing clinical-stage cancer candidates for patients of all ages, Day One CEO Jeremy Bender, Ph.D., said in the release.