Argenx to acquire peptide drug developer Unnatural Products for up to $1.15 billion
The immunology company agrees to buy Santa Cruz-based Unnatural Products, adding a macrocyclic peptide discovery engine, for $550 million upfront and up to $595 million in milestones.
Argenx announced a definitive agreement to acquire Unnatural Products, Inc. for $550 million in cash upfront, with up to $595 million in additional contingent payments tied to development and regulatory milestones, for total potential consideration of approximately $1.15 billion. The acquisition is expected to close by year-end 2026, subject to customary closing conditions.
Unnatural Products, headquartered in Santa Cruz, California, has built a macrocyclic peptide discovery engine that combines parallel experimentation with machine learning for medicinal chemistry.
Argenx CEO Karen Massey said the platform is highly complementary to the company's antibody engineering and creates new possibilities for oral and long-acting medicines. Morgan Stanley & Co. LLC served as financial adviser and DLA Piper LLP as legal counsel to argenx; Latham & Watkins LLP advised Unnatural Products.
Deal facts
- Target
- Unnatural Products
- Business
- Santa Cruz, California-based biotechnology company with a macrocyclic peptide discovery platform combining parallel experimentation and machine learning
- Buyer
- argenx
- Deal type
- Strategic
- Headquarters
- Santa Cruz, CA
- Value
- up to $1.15 billion
- Advisers
- Morgan Stanley & Co. LLC financial adviser to argenx
- DLA Piper LLP legal counsel to argenx
- Latham & Watkins LLP legal counsel to Unnatural Products
- Status
- Announced
- Announced
- Monday, November 9, 2026
Sources
- argenxNov 9, 2026
Written by Buyout Desk from the sources above. Spotted an error? Email corrections@buyoutdesk.com.