Gilead to buy PepStar's oral IL-23R peptide program

Gilead Sciences has agreed to buy an oral peptide program aimed at the IL-23 receptor from PepStar Therapeutics, a privately held company that Fierce Biotech describes as based in Shanghai. In a release dated Oct 22, 2026, Gilead said it signed a definitive agreement for the program, including its lead asset, HCXT-2001, and will gain worldwide rights.

Gilead will pay $1.275 billion in upfront cash, subject to customary adjustments, when the deal closes. The release does not mention milestone payments or royalties. Gilead expects closing in the fourth quarter of 2026, subject to customary conditions, and estimates the deal will cut its GAAP and non-GAAP earnings per share for that quarter by about $0.79 to $0.83.

What Gilead is buying

Gilead describes HCXT-2001 as an investigational oral macrocyclic peptide that inhibits the IL-23 receptor and has an extended half-life. It is in Phase 1 trials. “Its safety and efficacy have not been established, and it has not been approved by any regulatory authority,” the company said.

IL-23 is a signaling protein that drives inflammation in several immune-mediated diseases. Gilead is aiming the drug at inflammatory bowel disease (IBD), the group of conditions that includes Crohn’s disease and ulcerative colitis, and says the target also has potential uses in psoriasis.

Dietmar Berger, Gilead’s chief medical officer, said the company sees potential for HCXT-2001 “alone or in combination, including with emvistegrast, as a daily oral treatment for people living with IBD.” Emvistegrast is Gilead’s experimental oral inhibitor of the alpha-4 beta-7 integrin pathway. Reuters reported that the deal followed positive mid-stage results for emvistegrast announced earlier that week.

PepStar founder and CEO Haibing Guo said the deal “underscores the strength of our proprietary oral peptide platform.”

An early bet with no published data

The program is at an early stage. Citi analyst Geoffrey Meacham told Reuters the size of the upfront payment was notable because HCXT-2001 is still in early testing and has no published clinical data.

Fierce Biotech reported that two HCXT-2001 studies registered in China this year are enrolling healthy volunteers and looking at how food affects the drug, and that a third trial is enrolling healthy adults in New Zealand. Analysts at BMO Capital Markets called the deal “a logical complement to emvistegrast that sets up a potential all-oral combination,” the outlet said.

The Icotyde comparison

Oral peptides are unusual because most peptide drugs are broken down in the gut and must be injected. Johnson & Johnson’s Icotyde, which the UK regulator approved this month after a US approval in March, is also an oral peptide that blocks the IL-23 receptor. J&J calls it the first and only targeted oral peptide of its kind, and it is approved for plaque psoriasis. Fierce Biotech framed HCXT-2001 as a potential challenger to Icotyde, noting that PepStar extended its half-life. No study has compared the two drugs.

Gilead plans to report its third-quarter results on Oct 29, according to a company announcement.

What is not known

• Whether HCXT-2001 works or is safe. No clinical results have been published, and Gilead says safety and efficacy have not been established.
• The full deal terms. Gilead disclosed the upfront payment only; it has not said whether any later payments are owed.
• The development plan. Gilead has not said when IBD or psoriasis trials in patients will start.

We will update this story when the deal closes or Gilead releases clinical data.