Structure Therapeutics reports first clinical data for oral amylin drug ACCG-2671

Structure Therapeutics reported the first clinical data for an oral small-molecule amylin receptor agonist, ACCG-2671, on September 8, 2026, alongside 72-week weight-loss results for a second experimental pill, aleniglipron ^[1]. Both drugs are in clinical testing and neither is approved for sale ^[1].

What the ACCG-2671 data showed

In a Phase 1/2a single-dose trial, 31 healthy adults without obesity received one 1, 2, 5 or 10 mg dose of ACCG-2671 or a placebo ^[1]. The drug's half-life was about six days, which the company said supports further testing of weekly dosing, and the study reported no serious adverse events and no cases of drug-induced liver injury ^[1].

Exploratory results showed a single 10 mg dose (six participants) was associated with a mean 3.3% reduction in body weight at Day 24, and CTX-1, a biomarker of bone resorption, fell about 60% on Day 2 across the active dose groups ^[1]. No nausea or vomiting was reported in the placebo, 1 mg or 2 mg groups; gastrointestinal events emerged at 5 mg, with nausea in 4 of 5 participants and vomiting in 3 of 5, and all 6 participants at 10 mg had gastrointestinal events ^[1]. The company said these findings shaped the starting doses and titration plan now being used in the multiple-dose portion of the trial ^[1].

That portion is enrolling participants living with obesity for 84 days across five cohorts, testing daily and weekly regimens and including one cohort already taking a stable dose of an injectable GLP-1 receptor agonist ^[1]. Topline results are expected in the first half of 2027 ^[1].

What the aleniglipron data showed

The 72-week results come from an open-label extension of the Phase 2b ACCESS trial, in which 87% of eligible participants who finished the initial 36-week double-blind period continued treatment ^[1]. Participants originally assigned to the 45 mg, 90 mg and 120 mg arms who went on to dose up to 180 mg lost 11.6%, 14.4% and 16.2% of body weight respectively, with no sign of a plateau in the two highest-dose groups ^[1]. More than one-third of participants in the 90 mg and 120 mg groups lost more than 20% of body weight, with mean absolute losses of 35.9 and 40.5 pounds ^[1].

Participants who had been on placebo and crossed over started at a lower 2.5 mg dose and lost 9.0%, or 22.7 pounds, after 36 weeks ^[1]. Fewer than 5% of participants discontinued because of adverse events, no cases of drug-induced liver injury were reported, and liver enzyme elevations all resolved without stopping treatment ^[1]. Because participants reached the top 180 mg dose only around Week 60, exposure to that dose by Week 72 was limited, and the extension was open-label, meaning treatment assignments were known to participants and investigators ^[1].

Why it matters for patients

Both candidates are pills taken by mouth, which the company says could combine convenience with manufacturing that is scalable and cost-effective and could broaden access and choice for people living with obesity ^[1]. Neither drug is approved, and no information on price, insurance coverage, or how either compares with currently available treatments has been disclosed ^[1].

The ACCG-2671 weight finding comes from a single dose in six healthy participants without obesity, so it does not show how the drug performs in people with obesity; the aleniglipron figures come from an open-label extension with no placebo comparison at 72 weeks ^[1]. Whether either drug's weight loss holds up in larger randomized trials, and how it compares with the approved GLP-1 and GIP/GLP-1 medicines on the market, has not been reported ^[1].

What happens next

Structure Therapeutics began the Phase 3 ACCOMPLISH program in August 2026 ^[1]. ACCOMPLISH-1 (NCT07654361) is enrolling up to 3,600 adults with obesity or overweight plus at least one weight-related condition, and ACCOMPLISH-2 (NCT07654374) is enrolling up to 1,100 adults with obesity or overweight and type 2 diabetes ^[1]. Topline results from both are expected in the second half of 2028, and topline ACCG-2671 multiple-dose data are expected in the first half of 2027 ^[1].