The FDA has placed a full clinical hold on Aardvark Therapeutics’ IND for ARD-101, halting all ongoing clinical studies, including the Phase 3 HERO trial (AVK-101-301) and the Phase 3 open-label extension (AVK-101-302) in Prader-Willi syndrome (PWS).
The hold follows Aardvark’s earlier voluntary pause of a Phase 3 trial in March after a cardiac safety signal (QRS prolongation) was observed in a healthy volunteer study at twice the Phase 3 dose without titration.
As of February 27, 2026, 68 patients had been dosed in the randomized controlled HERO Phase 3 trial and 19 patients in the open-label extension study.
In response to the FDA hold and timing pressures on its development and financing plans, Aardvark will unblind accumulated data from both the HERO and OLE trials earlier than planned to evaluate the totality of available efficacy and safety data.
The company aims to use these unblinded data to determine next steps for the ARD-101 program and to support discussions with the FDA on resolving the clinical hold and defining a viable regulatory path forward.
Aardvark remains in active dialogue with the FDA and publicly reiterates its commitment to patient safety and to advancing ARD-101 as a potential treatment for hyperphagia in the underserved PWS population.
Prior clinical work suggested the approved Phase 3 dose of ARD-101 may be less likely to cause the QRS prolongation events seen at higher, non-titrated doses, but the FDA has nonetheless required a full hold pending further analysis.