Eli Lilly (LLY.US) shares opened lower and extended losses on Tuesday, falling more than 4% to $948.76 at the time of writing. The decline follows news that Structure Therapeutics (GPCR.US) announced positive results for its experimental weight-loss drug, aleniglipron. Data showed that patients lost approximately 15% of their body weight after 44 weeks of treatment. BMO Capital Markets analyst Evan Seigerman noted that the drug's efficacy "appears highly competitive" and may even surpass similar oral medications from Novo Nordisk (NVO.US) and Eli Lilly. Structure Therapeutics plans to initiate late-stage studies in the second half of 2026, using a "low and slow" dose titration approach to mitigate gastrointestinal side effects.