Aardvark Therapeutics voluntarily paused dosing and enrollment in its Phase III HERO trial of ARD‑101 for hyperphagia in Prader‑Willi syndrome after routine safety monitoring in a healthy‑volunteer study revealed reversible cardiac observations at supra‑therapeutic doses. The company said it will review safety data and dose selection before deciding next steps. The pause forced Aardvark to withdraw planned topline timing and sparked a steep share decline, underscoring how safety signals in healthy‑volunteer studies can derail late‑stage rare‑disease programs. ARD‑101 is a gut‑restricted TAS2R pan‑agonist intended to trigger satiety hormones; the observation highlights the need to reconcile mechanism, exposure margins, and cardiac monitoring in appetite‑modulating drugs.