Structure Therapeutics has touted the 16% weight loss—about 39 pounds—seen by aleniglipron as the best results yet for an oral GLP-1 drug, as the obesity biotech readies the candidate for phase 3.
The San Francisco-based company assessed daily aleniglipron against placebo in the phase 2 study, dubbed Access II, among 85 adults who are overweight or with obesity. Participants in the aleniglipron cohorts started on 5 mg of the GLP-1 drug and were titrated over four weeks up to doses of 120 mg, 180 mg or 240 mg.
At 44 weeks, Structure reported that these three dosing cohorts had achieved mean weight loss of 13.6%, 15.3% and 15%, respectively. Adjusted for placebo, that weight loss came in at 14.7%, 16.3% and 16%.
The biotech claimed these placebo-adjusted results showed that aleniglipron has the “highest efficacy among oral GLP-1 [receptor agonists] and comparable efficacy to injectable” GLP-1s. There was no evidence of weight loss plateauing by this point, the company added.
Novo Nordisk became the first—and, so far, the only—company to get an oral GLP-1 to market in the form of oral Wegovy, which launched at the start of the year. That 25-mg obesity pill demonstrated 16.6% weight loss over the longer period of 64 weeks in a phase 3 trial called Oasis 4.
Meanwhile, a 36-mg dose of Eli Lilly’s own oral GLP-1 orforglipron saw 12.4% weight loss at 72 weeks. Unveiling the data back in August 2025, Lilly’s chief scientific officer Daniel Skovronsky, M.D., Ph.D., argued that the result was “as good as it gets” for a GLP-1 monotherapy in the once-a-day small molecule arena.
Related
When it came to tolerability, Structure said today that aleniglipron had a profile “consistent” with other GLP-1s. As with other drugs in this class, the most common adverse events (AEs) were gastrointestinal, while the two most common AEs in the titration phase were nausea and vomiting, according to the biotech.
There was only one AE-related treatment discontinuation in the Access II study for participants receiving doses of 120 mg or higher from 28 to 44 weeks, the company noted.
Investors didn’t appear blown away by this morning’s readout—sending Structure’s stock up 4% to $56.10 per share as of 10 a.m. ET from a Friday closing price of $53.75. It’s a more subdued response than in December, when Structure’s share price doubled after the company tied the 120-mg dose of aleniglipron to 11.3% placebo-adjusted weight loss at 36 weeks in a separate study called Access.
About 10% of patients in that original Access trial had discontinued the study due to AEs, and Structure appeared to address this concern head-on in this mornings’ release. The company said it has been conducting a body composition study of 71 patients, which has suggested that kicking off dosing at 2.5 mg—as opposed to 5 mg—for the initial four weeks was resulting in “meaningful improvements in AE-related discontinuations.”
Meanwhile, an open-label extension of the original Access study has demonstrated continued weight loss of up to 16.2% for the 120-mg dose at 56 weeks, the company noted. For the extension study, an overall AE-related discontinuation rate of 2% has been reported for patients with a median follow-up of 20 weeks.
Related
Structure CEO Raymond Stevens, Ph.D., said in a statement that the “totality of efficacy and tolerability data” across both the Access and Access II studies “continue to demonstrate clear differentiation of aleniglipron, with the highest weight loss observed for an oral GLP-1RA to date and a safety profile appropriate for chronic use in a disease that impacts millions of people.”
“The consistent weight loss observed across multiple studies to date reaffirms aleniglipron’s potential to be a best-in-class oral GLP-1, with injectable-like efficacy that could become a backbone oral small molecule therapy for obesity,” Stevens added.
William Blair analysts offered two ways to view this morning’s readout. On the one hand, they suggested the latest data “offer another set of positive datasets for aleniglipron.”
However, the analysts argued that differences in trial design, such as adding higher doses to the Access II study, “complicates direct comparisons” to Lilly’s orforglipron.
“As such, it is our view that it is premature to label aleniglipron as differentiated against orforglipron or best-in-class,” the analysts concluded.
The plan for Structure is to meet with the FDA in the second quarter ahead of an anticipated phase 3 launch in the second half of the year.
Editor’s note: This story was updated at 12:40 p.m. ET on March 16 to include analyst commentary.
