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Structure Therapeutics Reports 16.3% Weight Loss With Oral GLP-1 Pill Aleniglipron in Phase 2 Trial

#GLP-1#aleniglipron#Structure Therapeutics#oral GLP-1#Phase 2#obesity#clinical trial#weight loss

Structure Therapeutics (NASDAQ: GPCR) has reported positive topline results from its Phase 2 ACCESS II clinical trial evaluating aleniglipron, a once-daily oral small-molecule GLP-1 receptor agonist, in adults living with obesity or overweight. The company, headquartered in South San Francisco with research operations in Shanghai, announced that the highest dose achieved 16.3% placebo-adjusted weight loss at 44 weeks — a result that positions the oral pill as a serious competitor to injectable peptide-based obesity drugs.

Aleniglipron (formerly known as GSBR-1290) is an orally available small molecule that activates the glucagon-like peptide-1 (GLP-1) receptor, the same biological target as semaglutide, a GLP-1 receptor agonist sold as Ozempic and Wegovy by Novo Nordisk. The key difference: aleniglipron is a pill, not an injection.

Key trial findings

The ACCESS II trial enrolled patients across multiple dose cohorts with a titration-based dosing strategy designed to improve tolerability. Key results include:

  • 16.3% placebo-adjusted weight loss at the highest dose (240 mg) at 44 weeks
  • No plateau observed in the weight-loss curve, suggesting further reductions could occur with longer treatment
  • Tolerability profile consistent with the GLP-1 receptor agonist class, with gastrointestinal side effects (nausea, vomiting) as the most common adverse events
  • A lower starting dose with slower titration significantly reduced early discontinuation rates compared to the first ACCESS trial

A companion body composition study using a lower 2.5 mg starting dose also showed promising results, confirming that the titration approach can meaningfully reduce the GI side effects that plague the entire GLP-1 drug class.

Why it matters for the peptide landscape

The results arrive as the GLP-1 market undergoes a fundamental shift. While injectable peptide drugs like semaglutide and tirzepatide, a dual GIP/GLP-1 receptor agonist marketed as Mounjaro and Zepbound by Eli Lilly, continue to dominate, the pharmaceutical industry is racing to develop oral alternatives that could dramatically expand the patient population willing to start treatment.

Eli Lilly's orforglipron, another non-peptide oral GLP-1 agonist, is already in Phase 3 trials. Ambrosia Biosciences recently raised $100M for its own oral small-molecule GLP-1 program. Novo Nordisk's oral semaglutide (Rybelsus), while already approved, uses a peptide formulation with bioavailability limitations.

Structure Therapeutics plans to advance aleniglipron into Phase 3 trials in the second half of 2026, with regulatory filings potentially following in 2028.