Structure Therapeutics reports 16.2% weight loss at 72 weeks for oral aleniglipron

Structure Therapeutics reported on Sept. 8, 2026 that its experimental once-daily oral pill aleniglipron produced up to 16.2% average weight loss at 72 weeks in an open-label extension study, with fewer than 5% of participants across all dose groups stopping treatment because of side effects ^[1]. Aleniglipron is a small-molecule GLP-1 receptor agonist in development for obesity and is not approved by the FDA ^[2].

Analysts at BMO Capital Markets called the 72-week result "in line" with Novo Nordisk's oral Wegovy (semaglutide), which showed 16.6% weight reduction at 64 weeks in the Phase 3 OASIS-4 trial, and said it "best" Eli Lilly's recently launched Foundayo (orforglipron), which produced 12.4% weight loss at 72 weeks at a 36 mg dose in the Phase 3 ATTAIN-1 trial ^[1]. The company said participants were still losing weight at 72 weeks, "with no evidence of a plateau" ^[1]. Leerink Partners wrote that the data "support potential best-in-class efficacy" ^[1].

Those comparisons come from separate trials with different designs, dose levels, treatment durations and populations. None of the studies tested the drugs against each other, so the percentages do not establish that one medicine works better than another.

The two sources describe the dose behind the 16.2% figure differently. BioSpace attributes the result to the 180 mg dose ^[1], while Structure's June 5, 2026 announcement of the same extension reported weight loss of 13.3%, 16.2% and 15.3% in participants coming from the 45 mg, 90 mg and 120 mg arms of the earlier double-blind treatment period ^[2]. The sources do not reconcile the dose labeling, and the exact dosing schedule used in the extension has not been explained.

Discontinuation numbers also differ depending on which part of the program is measured. Structure said fewer than 5% of participants in the extension across all dose groups stopped treatment because of adverse events ^[1]. The company's June announcement reported a 10.4% overall discontinuation rate in the Phase 2b ACCESS trial, which preceded the extension ^[2]. Gastrointestinal side effects were described as similar to those seen with approved GLP-1 medicines — generally mild to moderate and less frequent over time — and most discontinuations happened during the initial dose increases ^[2].

Structure also reported early data for a second pill, ACCG-2671, an oral dual amylin and calcitonin receptor agonist ^[1]. In a Phase 1/2a single-dose study in healthy participants without obesity, the drug showed a half-life of about 6 days, which the company said supports weekly dosing. A single 10 mg dose produced a 3.3% mean reduction in body weight; the 1 mg and 5 mg doses produced 0.9% and 1.2%, and participants who received 2 mg gained 0.1% ^[1]. The company also reported a decrease in CTX-1, which it described as a biomarker of bone breakdown relevant to bone health ^[1]. Leerink noted high rates of gastrointestinal side effects: nausea and vomiting occurred in 60% to 100% of participants at the 5 mg and 10 mg doses, and the study did not use step-up dosing ^[1]. CEO Raymond Stevens said the compound represents "the first reported clinical data for an oral small molecule amylin receptor agonist" ^[1].

Why it matters for patients

Both compounds are experimental. Aleniglipron and ACCG-2671 are not FDA-approved, and the sources do not describe any way for patients to obtain them outside a clinical trial ^[1][2].

For people who dislike injections, the appeal of these candidates is partly about form: both are oral, with aleniglipron taken once daily and ACCG-2671 dosed once weekly in early testing ^[1][2]. Tolerability matters just as much, because a drug only helps if people can stay on it. The extension reported a discontinuation rate below 5% for aleniglipron ^[1], while the earlier ACCESS trial reported 10.4% overall ^[2]. It has not been reported how many extension participants took each dose, how the 72-week numbers compare with a placebo, or whether the results will hold up in larger randomized trials.

The extension was open-label, meaning participants and investigators knew who was receiving treatment, and its purpose was to follow participants after the main trial rather than to compare the drug against a placebo ^[1][2]. That limits how directly the 72-week figure can be weighed against results from the controlled trials cited for oral Wegovy and Foundayo ^[1].

What happens next

The Phase 3 ACCOMPLISH program for aleniglipron began in August 2026, with top-line data expected in the second half of 2028, according to Leerink ^[1]. Structure said in June that Phase 3 would start with a 2.5 mg starting dose, chosen after a meeting with the FDA, and that it intended to evaluate multiple doses ^[2]. Dates for the next ACCG-2671 trials have not been reported ^[1]. Whether either drug will be submitted to the FDA for approval, and when, has not been disclosed ^[1][2].