Gilead Sciences has entered into a definitive agreement to acquire an oral IL-23R inhibitor program, including lead asset HCXT-2001, from PepStar Therapeutics, a privately held, clinical-stage biotechnology company.

HCXT-2001 is an investigational, clinical-stage, oral, macrocyclic peptide inhibitor of IL-23R with an extended half-life, offering a potentially differentiated approach to oral IL-23 pathway inhibition. IL-23R is a clinically validated target in immune-mediated inflammatory diseases, including Inflammatory Bowel Diseases (IBD), with potential applications in psoriasis.

The transaction provides Gilead with worldwide rights to the IL-23R inhibitor program, including HCXT-2001, and further strengthens Gilead’s growing inflammation and immunology portfolio, where the company is building depth and optionality in selected immune-mediated diseases through multiple complementary mechanisms and modalities.

Dietmar Berger, MD, PhD, Chief Medical Officer, Gilead, said, “HCXT-2001 adds a potentially differentiated oral approach to our growing inflammation pipeline, reflecting our commitment to addressing significant unmet patient needs. We see potential for HCXT-2001 alone or in combination, including with emvistegrast, as a daily oral treatment for people living with IBD.”

Under the terms of the agreement, Gilead will acquire an oral IL-23R inhibitor program, including lead asset HCXT-2001, from PepStar for USD 1.275 billion in upfront cash consideration, subject to customary adjustments, which is payable at closing. Closing of the transaction is subject to certain customary conditions. The transaction is expected to close in the fourth quarter of 2026.

Haibing Guo, Founder and CEO, PepStar, said, “We are excited for Gilead to take HCXT-2001 forward and believe their scientific expertise and global development capabilities can help realise the full potential of this novel oral IL-23R inhibitor. This transaction marks a major milestone for our company and underscores the strength of our proprietary oral peptide platform. I feel incredibly proud of what our team has accomplished in just 3 years and excited about what lies ahead as we continue bringing innovative medicines to patients around the world.”

This transaction is expected to reduce Gilead's Generally Accepted Accounting Principles (GAAP) and non-GAAP EPS by approximately USD 0.79 to USD 0.83 in the fourth quarter of 2026.