Gilead Sciences moved deeper into antibody-drug conjugates by agreeing to buy German ADC specialist Tubulis in a deal structured around a $3.15 billion upfront payment and up to $1.85 billion in milestones. Tubulis’ lead asset, TUB-040, is a NaPi2b-directed topoisomerase I inhibitor ADC in Phase Ib/II trials for platinum-resistant ovarian cancer and non-small cell lung cancer. The FDA granted fast track designation to TUB-040 in June 2024. The acquisition also adds TUB-030, a 5T4-targeted ADC in development for multiple solid tumors. Management framed the transaction as a continuation of Gilead’s recent oncology M&A streak and as an expansion of next-generation ADC capabilities, including technologies intended to reduce off-target toxicity. Tubulis will operate as a dedicated ADC research organization within Gilead after the transaction closes, expected in Q2 2026. Investors will now watch how quickly Gilead integrates Tubulis discovery, manufacturing, and clinical development resources—and whether TUB-040’s clinical readouts support a rapid path toward pivotal trials and broader label expansion.