argenx to acquire Unnatural Products in deal worth up to $1.15 billion

argenx announced on November 9, 2026 a definitive agreement to acquire Unnatural Products, Inc. (UNP), a move the company said would add a peptide discovery engine to broaden its immunology capabilities.¹ argenx already held a minority stake in UNP, and the new agreement covers the purchase of all remaining shares, in a transaction valuing UNP at up to approximately $1.15 billion across upfront and milestone payments.¹

Under the deal's financial terms, argenx will pay $550 million upfront in cash on hand, with up to $595 million more tied to development and regulatory milestones, for total potential consideration of roughly $1.15 billion.¹ Both companies' boards have signed off, and the acquisition is expected to close by the end of the year, subject to customary closing conditions.¹

Morgan Stanley is acting as argenx's financial advisor, with DLA Piper serving as its legal counsel, while Latham & Watkins is acting as legal counsel to UNP.¹

Based in Santa Cruz, California, UNP has built a platform aimed at macrocyclic peptide chemistry that pairs parallel experimentation with machine learning methods.¹ Following the deal's close, UNP's team and leadership are set to remain in Santa Cruz, continuing to lead its discovery work within a strategic framework agreed with argenx,¹ while argenx plans to contribute its clinical development and commercialization capabilities to advance those medicines toward patients.¹

argenx CEO Karen Massey said the company is investing with discipline as it builds its next chapter, aiming to be the leading immunology innovation company.¹ UNP co-founder and CEO Cameron Pye called the announcement a milestone reflecting the work of UNP's scientists, employees, collaborators and supporters.¹