Galapagos NV (NASDAQ: GLPG) announced it has entered into a binding agreement with Gilead Sciences Inc. related to Gilead's acquisition of Ouro Medicines LLC, a biotechnology company developing T cell engager therapies for autoimmune diseases.

The partnership centers on gamgertamig (OM336), a clinical-stage BCMAxCD3 T cell engager designed for plasma and B-cell depletion through subcutaneous treatment. The drug has received Fast Track and Orphan Drug Designation from the U.S. FDA for treating autoimmune hemolytic anemia and immune thrombocytopenia, with registrational studies expected to begin in 2027.

Under the framework agreement, Galapagos will pay 50% of Gilead's $1.675 billion upfront consideration for acquiring Ouro, plus 50% of up to $500 million in contingent milestone payments. The company will fund development costs prior to registrational studies, while later-stage development costs will be shared equally between the parties.

Galapagos will receive tiered royalties between 20-23% on net sales of gamgertamig upon commercialization. The company is also eligible for up to $100 million in milestone payments when Gilead initiates registrational trials for the drug in additional indications.

The agreement includes a waiver allowing Galapagos to deploy $500 million of available cash independently from Gilead, including up to $150 million for potential share buybacks. The company will also gain access to three additional preclinical autoimmune programs from Ouro.

As of December 31, 2025, Gilead owned 25.35% of Galapagos shares through a subsidiary. A committee of three independent board members reviewed the transaction under Belgian corporate law requirements and concluded the agreement would not result in disadvantages outweighing benefits to the company.

The framework agreement becomes effective upon completion of Gilead's acquisition of Ouro.