A Multicenter, Randomized, Double-blind, Placebo-controlled Phase III Clinical Study to Evaluate the Efficacy and Safety of HRS9531 Injection in Subjects With Obstructive Sleep Apnea (OSA) and Obesity Who Are on Positive Airway Pressure Ventilation (PAP) Therapy

Prior treatment

• Prior/planned OSA-related major surgeries (e.g., tonsillectomy/adenoidectomy) that may affect breathing.
• Have used drugs or treatments that may cause significant weight gain or loss within 3 months
• Investigator-determined unsuitability/unwillingness to pause PAP therapy for at least 1 week pre-PSG (e.g., safety/occupational/personal considerations).

Other illness

• Endocrine disorders significantly affecting weight (e.g., Cushing's syndrome, hypo-/hyperthyroidism) or monogenic/hereditary obesity syndromes excluded.
• Diabetes mellitus (excluding gestational diabetes).
• Respiratory and neuromuscular diseases that could interfere with the results of the trial in the opinion of the investigator.
• Impaired gastric emptying (e.g., gastric bypass, pyloric stenosis)；Chronic use of GI motility-affecting drugs；Severe GI disorders (e.g., active PUD, IBD)；GI surgeries (except non-motility-affecting procedures)
• Pancreatic disorders (acute/chronic pancreatitis, pancreatic injury)；Acute cholecystitis history；Symptomatic/treated gallbladder disease

Other

• Have significant craniofacial abnormalities that may affect breathing at baseline
• Have diagnosis of Central or Mixed Sleep Apnea with % of mixed or central apneas/hypopneas ≥50%, or diagnosis of Cheyne Stokes Respiration

• Aged 18 -75 (inclusive), male or female Sex
• BMI ≥28.0 kg/m2；
• ≥3 months of diet/exercise control pre-screening with ≤5.0 kg weight fluctuation in prior 3 months.
• Confirmed OSA diagnosis with screening PSG showing AHI ≥15.0 events/h.
• ≥3 months of PAP therapy pre-screening with planned continuation; willingness to pause PAP ≥1 week before each PSG.
• Females/males of childbearing potential must use highly effective contraception from consent until 2 months post-treatment, with no pregnancy/donation plans. Females require negative pregnancy test ≤3 days pre-randomization and non-lactating.