Gilead Sciences moved deeper into antibody-drug conjugates by agreeing to buy privately held German firm Tubulis in a deal worth up to $5 billion, including $3.15 billion upfront and as much as $1.85 billion in milestones. The acquisition is positioned to expand Gilead’s ADC depth beyond its anchor asset Trodelvy. Tubulis’ lead candidate, TUB-040, is a NaPi2b-directed topoisomerase I inhibitor ADC in Phase Ib/II testing (NAPISTAR1-01; NCT06303505) for platinum-resistant ovarian cancer and non-small cell lung cancer. A separate program, TUB-030, is a 5T4-targeting ADC aimed at multiple solid tumor types, with Tubulis’ linker and payload platforms designed to broaden therapeutic payload options. The transaction is expected to close in 2Q26, with Tubulis planned to operate as a dedicated ADC research organization within Gilead, centered in Munich. The messaging from both companies emphasizes platform value—rather than only near-term clinical assets—within Gilead’s oncology portfolio build-out.