AMSTERDAM, the Netherlands, Nov. 9, 2026 — argenx (Euronext & Nasdaq: ARGX), the immunology innovation company, announced a definitive agreement to acquire Unnatural Products (UNP), adding a macrocyclic peptide discovery engine to its immunology innovation capabilities. argenx, which already holds a minority stake in UNP, will acquire all remaining shares in a transaction valuing UNP at up to approximately $1.15 billion across upfront and milestone payments.
The acquisition expands the ways argenx can pursue novel biology and develop oral or long-acting medicines for people living with serious immune-mediated diseases. Karen Massey, CEO of argenx, said UNP's macrocyclic peptide capabilities are highly complementary to the company's antibody engineering and create new possibilities for oral and long-acting medicines, adding that after more than two years of collaboration, argenx will preserve UNP's science-first, entrepreneurial and patient-focused way of working.
Under the terms, argenx will pay an upfront payment of $550 million in cash on hand and up to $595 million in payments contingent on specified development and regulatory milestones, for total potential consideration of up to approximately $1.15 billion. The boards of both companies have approved the transaction, which is expected to close by the end of the year subject to customary closing conditions.
Following closing, UNP's team and leadership will continue to operate from its Santa Cruz, California site, which will serve as argenx's home for peptide discovery, and UNP will continue to lead its discovery work within a strategic framework agreed with argenx. UNP's platform addresses the medicinal chemistry complexities of macrocyclic peptides through parallel experimentation and machine learning, developing therapeutic macrocycles against high-value, traditionally difficult-to-drug targets.

Source: https://kessler-prod.reta52d8.eas.morningstar.com/news/globe-newswire/1001302467/argenx-to-acquire-unnatural-products-inc-adding-peptide-discovery-engine-to-broaden-immunology-capabilities