Aardvark Therapeutics’ Prader-Willi syndrome program hit a roadblock as the FDA placed a full clinical hold on ARD-101. The hold escalates an earlier trial pause after a cardiovascular safety signal emerged in a healthy-volunteer study at higher doses than those used in the company’s other trials. Aardvark said it will unblind data from its Phase 3 trial and associated open-label extension to help regulators determine whether a path forward exists for dosing, study design, and the overall risk-benefit profile. The company reported it has dosed 68 patients in the randomized Phase 3 study and 19 in the open-label extension before the pause and subsequent hold. The hold also introduces a financing timing risk for the company, which previously anticipated key readouts as part of efforts to fund the program through late 2026 and beyond. Regulatory clearance in rare metabolic disorders often hinges on clarity around cardiovascular risk and whether mitigation strategies can preserve efficacy; the unblinding step is now central to any next FDA discussion.