Gilead will acquire antibody-drug conjugate (ADC) developer Tubulis in a deal worth up to $5bn, continuing the big pharma company’s recent string of high-profile M&A activity in 2026.
As per the agreement, Gilead will pay $3.15bn upfront and up to $1.85bn in milestones to buy the German biotech. Following the transaction’s close, set for Q2 2026, Tubulis will become an ADC research organisation within Gilead.
Tubulis’ catalogue of drugs is headed by TUB-040, a NaPi2b-directed topoisomerase-I inhibitor (TOPO1i) ADC that is currently in Phase Ib/II trials for platinum-resistant ovarian cancer and non-small cell lung cancer (NSCLC). The asset produced positive safety and efficacy results in the former indication in early data shared in October 2025. Gilead will also acquire TUB-030, a 5T4 targeted ADC for solid tumour treatment, as well as other assets that are being developed for undisclosed cancer indications.
Gilead’s CEO Daniel O’Day said: “The agreement to acquire Tubulis is a significant milestone in Gilead’s progress in oncology. The company brings a clinical-stage candidate that is a potential new treatment for ovarian cancer, as well as a next-generation ADC platform and a promising early pipeline.”
The acquisition brings an exit for the biotech that has been making a name for itself in the ADC arena. The biotech started working with Gilead in 2024, when the two companies began an option and license agreement worth up to $465m, allowing the US drugmaker access to Tubulis’ ADC platforms. Tubulis’ work had already attracted the interest of Bristol Myers Squibb (BMS), which paid $23m upfront and outlaid over $1bn in milestone payments for its own license agreement in 2023. Investors, too, have been impressed by Tubulis’ technology – a $361m Series C raise was completed in October 2025.
O’Day added: “Today’s agreement follows a two-year collaboration with Tubulis, which has given us strong conviction in their programmes and research capabilities.”
The Tubulis acquisition represents another major expansion into the ADC market made by Gilead in the past decade. In 2020, the company paid $21bn to acquire Immmunomedics. The deal saw Trodelvy (sacituzumab govitecan-hziy), an ADC approved for breast and urothelial cancer, start a new ownership journey under Gilead. Trodelvy’s global sales reached $1.4bn in 2025, up 6% from 2024.
ADCs are one of the fastest-growing modalities in cancer therapeutics. Constituting a monoclonal antibody (mAb) armed with a cytotoxic payload, they can target tumour cells without harming healthy tissue. A report from GlobalData forecasts that the ADC market size is growing at a CAGR of 25.16%, and is due to reach $65.2bn in sales in 2031. By this year, 11 ADC products are slated to have blockbuster status, as per the analysis.
GlobalData is the parent company of Pharmaceutical Technology.
Away from the ADC market, buying Tubulis marks the third M&A transaction completed by Gilead already this year. In February, the drugmaker bought immunotherapy specialist Arcellx for $7.8bn. This deal was swiftly followed a month later by a $2.2bn deal to take over T-cell engager developer Ouro Medicines for $2.2bn.
Gilead has also struck licensing agreements in 2026, including a $1.7bn deal with LEO Pharma and a $1.53bn transaction with China-based Genhouse Bio.
Reacting to the Tubulis deal, Citi analysts said in a research note: "We see this as an impactful expansion of Gilead's oncology portfolio, already anchored by Trodelvy's commercial momentum and the upcoming Arcellx cell therapy launch."
