FDA put a full clinical hold on Aardvark Therapeutics’ ARD-101, freezing the Phase 3 HERO study for Prader-Willi syndrome hyperphagia and its open-label extension — all ongoing trials stopped.
The hold came Thursday after market close. Aardvark had already paused HERO in late February after detecting cardiac signals in a healthy volunteer study. Two patients dosed at 1,600 mg twice daily, double HERO’s therapeutic target, showed echocardiograph patterns indicative of lower heart efficiency. That dosing was part of a routine safety study to support a regulatory application for ARD-101. Aardvark’s stock crashed nearly 30% to $4.73 per share before Friday’s opening bell.
Stifel wrote in a March 1 note: “It’s hard for us to have any confidence here.” The deeper problem: even if lower doses prove safe, that could compromise or cap ARD-101’s efficacy. William Blair didn’t ease concerns in a May 5 note, writing that “the cardiac events could be mechanism-based and call into question the therapeutic window of ARD-101.”
ARD-201, Aardvark’s obesity candidate built on ARD-101’s design and mechanism, is also suspended. In mid-March, Aardvark paused Phase 2 POWER and STRENGTH. POWER tests whether ARD-201 can maintain weight loss in patients who had received GLP-1s; STRENGTH assesses ARD-201’s additive benefits when used alongside GLP-1s. Both are now on ice.
Aardvark’s Q1 report, released last week, confirmed the company is still in discussions with FDA over ARD-101’s future.
Sarah Chen