David Happel of Sagimet talks about what denifanstat must prove in the U.S. | 2026 Fall Clinical Derm

Sagimet Biosciences has begun screening patients for a U.S. phase 3 trial of denifanstat, an investigational once-daily oral acne pill, and the company's CEO said results similar to those seen in China should be enough to win over dermatologists and payers.

In this interview with Managed Healthcare Executive, David Happel, CEO of Sagimet, discusses what the U.S. trial needs to show and what long-term data suggest about denifanstat as a chronic therapy. Happel said U.S. results that match the efficacy and safety seen in China should lead the dermatology and payer communities to embrace the drug. Because acne develops the same way regardless of a patient's background, he said, the company expects the results to carry over.

Happel also pointed to 52-week data from a phase 3 open-label extension in China, presented at the 2026 Fall Clinical Dermatology Conference. By week 52, 55.6% of patients who switched from placebo and 57.8% of those on denifanstat throughout reached treatment success, defined as clear or almost-clear skin with at least a 2-point improvement on the Investigator's Global Assessment (IGA). Inflammatory lesions fell 75.8% and 78.1%, respectively.

“I think the IGA getting to about 55%, 57% shows remarkable improvement over time. Meaning that the longer the patients take it, the better they become," Happel said.

He also noted that former placebo patients caught up to those treated from the start within about 12 weeks. Some long-term acne studies show results leveling off after 12 or 13 weeks, he said, sometimes because of poor adherence, side effects or the need to stop antibiotics to prevent resistance.

That long-term picture matters for a condition that often lasts a decade or more, Happel said. Patients with moderate to severe acne frequently cycle through oral antibiotics three months on and three months off. Acne on the chest and back is also harder to treat, and topicals there often require a caregiver to apply them, leaving room for an oral option.

Denifanstat, which blocks an enzyme that drives the skin's oil production, does not permanently change the disease, Happel said. Enzyme levels return to baseline four to six weeks after stopping, and acne can begin returning around the four-week mark. That gives dermatologists flexibility to keep patients on the drug long term or restart treatment as needed, he said.