Sidley Represents PepStar Therapeutics in US$1.275 Billion Sale of IL-23R Inhibitor Program to Gilead Sciences

Sidley represented PepStar Therapeutics Limited, a privately held, clinical-stage biotechnology company, in its definitive agreement to sell its investigational oral IL-23 receptor (IL-23R) inhibitor program, including lead asset HCXT-2001, to Gilead Sciences, Inc. (Nasdaq: GILD) for US$1.275 billion in upfront cash consideration, subject to customary adjustments. HCXT-2001 is a clinical-stage oral macrocyclic peptide inhibitor of IL-23R with potential applications in inflammatory bowel disease and other immune-mediated inflammatory conditions. The transaction is expected to close in the fourth quarter of 2026.

More information about the transaction is available here.

The Sidley team was led by Lila Hope (Technology and Life Sciences Transactions) and Geoffrey Levin (Private Equity), and included Jiqiang Lin, Jennifer Raab, and Yuhan Wu (Technology and Life Sciences Transactions); Elina Sigal (Private Equity); Mayan Katz and Steven Przesmicki (Emerging Companies and Venture Capital); Leila Malek, Joel Sontag, and Jason Nelson (M&A); Cole Rianda (Privacy and Cybersecurity); Arif Noorani (Food, Drug and Medical Device); James Mendenhall and Alessandra Moroni (Global Arbitration, Trade and Advocacy); Vadim Brusser and Miriam Silvestri (Antitrust and Competition); and Christian Brause (Tax).