Aardvark Therapeutics said the FDA has placed a full clinical hold on all tests of its Prader-Willi syndrome program, halting activity after a cardiovascular safety signal emerged earlier in healthy-volunteer dosing at higher than intended exposures. The hold stops trials involving ARD-101, the company’s small-molecule metabolic therapy designed to address hyperphagia. Aardvark plans to unblind data from a Phase 3 trial and an open-label extension to help regulators evaluate the totality of efficacy and safety signals and determine next steps. The company reported it has dosed 68 participants in the placebo-controlled Phase 3 study and 19 in the open-label extension. The hold compounds a tight execution and financing timeline. With cash run-rate expectations previously mapped to mid-2027, unblinding and any FDA-agreed pathway will likely need to be completed quickly to preserve patient access and support fundraising. The affected regulatory decision also positions competitors around Vyktat (soleno Therapeutics) as the existing approved option for PWS hyperphagia, increasing scrutiny on whether ARD-101’s risk-benefit can be redesigned under FDA dosing expectations.