Structure Therapeutics' Aleniglipron (GSBR-1290) Delivers 16% Weight Loss, Advancing to Phase 3
On March 16, 2026, Structure Therapeutics Inc. (NASDAQ: GPCR) announced positive topline results from its Phase 2 ACCESS II and ACCESS Open-Label Extension (OLE) clinical trials evaluating aleniglipron (GSBR-1290), once-daily oral non-peptide small-molecule GLP-1 receptor agonist. The data comprehensively support the drug's advancement into a Phase 3 clinical development program planned for the second half of 2026.
Aleniglipron belongs to the same chemical class as Eli Lilly's recently approved Eli Lilly's Foundayo (Orforglipron) Secures FDA Approval as First Food-Flexible Oral GLP-1, but its Phase 2 weight loss data are among the highest reported for an oral GLP-1 therapy, rivaling the efficacy of injectable formulations.
Key Phase 2 ACCESS II Efficacy Results (44 Weeks)
The 44-week ACCESS II study evaluated higher doses of aleniglipron (up to 240 mg once daily) in 85 adults with obesity or overweight.
- 180 mg Dose: Achieved a mean weight loss of 15.3% from baseline, resulting in a placebo-adjusted mean weight loss of 16.3% (39 lbs) (p<0.0001).
- 240 mg Dose: Achieved a mean weight loss of 15.0% from baseline, resulting in a placebo-adjusted mean weight loss of 16.0% (37 lbs) (p<0.0001).
- No Weight Loss Plateau: Weight loss trajectories in both the ACCESS II and OLE studies continued downward out to 44 and 56 weeks, respectively, with no evidence of flattening.
- Open-Label Extension (OLE): Patients transitioning to the OLE study achieved continued weight loss of up to 16.2% (40.5 lbs) with the 120 mg dose at 56 weeks.
Tolerability and the 2.5 mg Titration Strategy
A major challenge for oral small-molecule GLP-1 agonists has been gastrointestinal tolerability during the dose escalation phase. In previous studies starting at 5 mg, discontinuation rates due to adverse events (AEs) were higher.
- Structure's ongoing body composition and OLE studies evaluated a lower starting titration dose of 2.5 mg.
- This lower starting dose profoundly improved tolerability, resulting in overall AE-related discontinuation rates of just 2.0% in the OLE study and 3.4% in the body composition study after a median follow-up of 20 weeks.
- Importantly, across all studies involving over 625 participants, there were no cases of drug-induced liver injury, no persistent liver enzyme elevations, and no QTc prolongation.
Corporate Strategy and Financial Position
Structure Therapeutics is a clinical-stage biotechnology company with a market capitalization of $2.80 billion. The company reported a net loss of $76.2 million for the quarter ending March 31, 2026, as it scaled up R&D operations. It remains well-capitalized with $316.2 million in cash and only $5.8 million in total debt to fund its upcoming clinical trials.
The company has scheduled a Type B End-of-Phase 2 meeting with the FDA in Q2 2026 to finalize the Phase 3 design, which will utilize the 2.5 mg starting dose and evaluate doses up to 240 mg. Phase 3 trials are on track to initiate in the second half of 2026.