Aardvark Therapeutics halted dosing and enrollment in its Phase 3 HERO trial testing ARD‑101 for hyperphagia in Prader‑Willi syndrome after routine safety monitoring detected reversible cardiac observations in a separate healthy‑volunteer study at supra‑therapeutic doses. The company paused both the pivotal study and an open‑label extension while it reviews the findings. Management emphasized patient safety as the priority and said it will analyze the higher‑dose signals to inform optimal therapeutic dosing. The voluntary pause forced the company to abandon expectations of a near‑term topline readout and delayed its clinical timeline. The market reaction was immediate: Aardvark shares plunged more than 50% on the announcement. The pause also reverberates across the Prader‑Willi therapeutic landscape, where recent approvals (eg, Vykat) have underscored both unmet need and regulatory scrutiny for safety in this vulnerable population.