The FDA placed a full clinical hold on Aardvark Therapeutics’ Prader-Willi syndrome program, halting all tests of its small-molecule candidate ARD-101. The hold escalated a trial stoppage that began after a cardiovascular safety signal emerged in a healthy-volunteer study. Aardvark said it plans to unblind data to help regulators and investigators determine next steps. The company has already dosed participants in a Phase 3 placebo-controlled trial and an open-label extension, and it previously estimated topline data timing that now faces compression. For rare-disease sponsors, the decision highlights how volunteer safety findings can propagate into broader clinical pauses—and how quickly funding runway planning becomes central to next-step discussions with FDA.