Gilead Sciences has agreed to acquire German-based Tubulis for up to $5 billion, the companies said today, in a deal designed to expand the buyer’s antibody–drug conjugate (ADC) capabilities with a focus on fighting cancer.
Headquartered in Munich, privately held Tubulis has developed next-generation ADC candidates based on its own conjugation, linker and payload technologies intended to more selectively deliver diverse payloads to tumors deemed to be of high unmet need. The companies said Tubulis’ programs and platforms have broad potential across multiple tumor types, complementing Gilead’s development and commercialization expertise in oncology.
“We like the strategic fit and deal terms of the Tubulis (private) acquisition,” Daina M. Graybosch, PhD, senior managing director, immuno-oncology and a senior research analyst at Leerink Partners, wrote this morning in a research note. “This is more than an oncology bolt-on; we see real platform value in application of Tubulis’ ADC technologies to other therapeutic areas, namely virology.”
Tubulis’ lead pipeline candidate, TUB-040, is a sodium-dependent phosphate transport protein 2B (NaPi2b)-targeting topoisomerase-I inhibitor (TOPO1i) ADC that is now under study in the Phase Ib/II NAPISTAR1-01 trial (NCT06303505) assessing its safety, pharmacokinetics, and preliminary efficacy as a treatment for platinum-resistant ovarian cancer and non-small cell lung cancer (NSCLC).
In October at the European Society for Medical Oncology (ESMO), Graybosch noted, Tubulis presented data for TUB-040 showing a confirmed 50% overall response rate (ORR) and a 60% unconfirmed ORR across dose levels and irrespective of target antigen—results that were competitive with more mature datasets from leading TOPO1i ADCs.
“Though the dataset was early, and our primary outgoing question was how durability would mature, we suspect that Gilead saw durability maturing positively in their diligence,” Graybosch added. “If TUB-040 proves active in NSCLC, the program could complement their Trodelvy and IO [immune-oncology] lung programs. We wonder if Gilead saw early clinical NSCLC data in their diligence and if excitement around the emerging signal drove some of Tubulis’ valuation.”
Another Tubulis pipeline candidate, TUB-030, is a 5T4-targeting ADC that according to the companies has shown promising initial clinical data across various solid tumor types. TUB-030 is currently under study in the Phase I/IIa 5-STAR 1-01 trial (NCT06657222), a first-in-human study which aims to evaluate the safety, tolerability, pharmacokinetics, and efficacy of TUB-030 as a monotherapy in patients with advanced solid tumors. Tubulis has said it is developing TUB-030 for up to 13 undisclosed solid tumor indications.
Partners since 2024
The acquisition deal follows a two-year, up-to-$465 million collaboration with Tubulis launched in December 2024. Gilead gained access to Tubulis’ Tubutecan and Alco5 platforms after signing an exclusive option and license agreement to discover and develop an ADC against a solid tumor target.
At the time, Gilead agreed to pay Tubulis $20 million upfront, received an option that if exercised would have given Tubulis an additional $30 million—plus up to $415 million in payments tied to achieving development and commercialization milestones, as well as mid-single to low double-digit tiered royalties on sales of marketed products resulting from the collaboration.
“Today’s agreement follows a two-year collaboration with Tubulis, which has given us strong conviction in their programs and research capabilities,” Gilead Chairman and CEO Daniel O’Day said in a statement. “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.”
“Bringing this potential into Gilead would further expand what is already the strongest and most diverse pipeline in our company’s history,” O’Day declared.
Investors appeared less enthusiastic about the acquisition, as shares of Gilead dipped 1.7% in early Tuesday trading to $137.80 as of 12:01 p.m. ET.
Tubulis is Gilead’s third announced acquisition this year. The biotech giant announced plans in March to buy Ouro Medicines for up to $2.18 billion, and in February agreed to acquire Arcellx for up to $7.8 billion—for which it agreed last week to extend its tender offer until 5 p.m. ET on April 24.
Under the acquisition deal, Gilead agreed to acquire all of the outstanding equity of Tubulis for $3.15 billion in upfront cash payable at closing, and up to $1.85 billion in payments tied to milestones.
The transaction is expected to close in the second quarter subject to expiration or termination of specified regulatory filings and other customary conditions.
Upon closing of the deal, Tubulis will operate as a dedicated ADC research organization within Gilead, with the Munich site serving as a hub for ADC innovation, building on its integrated discovery, manufacturing, and clinical capabilities to advance next generation ADCs.
Gilead said it plans to finance the transaction with a combination of cash on hand and senior unsecured notes. Gilead finished 2025 with $10.605 billion of cash, cash equivalents and marketable debt securities, up from $9.991 billion as of December 31, 2024.
