FDA Places Full Clinical Hold on Aardvark Therapeutics’ ARD-101
Key Takeaways
- A full clinical hold suspends dosing and enrollment in the Phase III HERO study and open-label extension, superseding the earlier voluntary pause and freezing near-term registrational timelines.
- Cardiac safety signals emerged in healthy-volunteer exposure at supra-protocol doses, prompting intensified regulatory scrutiny and likely requirements for mechanistic clarification and revised risk-mitigation.
FDA places full clinical hold on Aardvark’s ARD-101 in Prader-Willi syndrome after heart-related adverse events, pausing late-stage studies and raising new questions around safety in appetite-regulation therapies
FDA placed a full clinical hold on Aardvark Therapeutics’ investigational new drug application for ARD-101.
The hold halts all ongoing clinical studies of the oral therapy for hyperphagia associated with Prader-Willi syndrome (PWS).
What affects will the clinical hold have?
The hold affects the company’s Phase III Hero trial and its open-label extension study evaluating ARD-101 in patients with PWS, following Aardvark’s previously disclosed voluntary pause on enrollment and dosing earlier this year.1 The company says it remains in active discussions with the FDA to determine a potential path forward for the program.
The regulatory action follows reports of heart-related adverse effects observed in healthy volunteers who received higher-than-planned doses of ARD-101.1
Shares of Aardvark fell roughly 14% in after-hours trading following the announcement, underscoring investor concerns about the future of the late-stage asset.
“We are continuing to work collaboratively with the agency to comprehensively evaluate the data and determine the best path forward for ARD-101,” said Tien Lee, MD, founder and CEO of Aardvark. “Patient safety will always be the highest priority for us, and we are deeply committed to the PWS community.”
The setback highlights the challenges companies developing therapies for rare metabolic and neurodevelopmental disorders face, particularly in areas with limited treatment options and high unmet need.1Hyperphagia, or insatiable hunger, is among the most debilitating symptoms of PWS and remains difficult to manage clinically.
What is ARD-101?
ARD-101 is designed to stimulate gut-peptide hormone release through activation of bitter taste receptors, with the goal of regulating appetite and satiety. The drug has advanced into late-stage development as one of the more closely watched oral investigational therapies for PWS-related hyperphagia.
What is Aardvark’s response to the clinical hold?
Following the regulatory discussions, Aardvark says its planning to unblind accumulated clinical data from both the Hero study and the extension trial to evaluate the overall safety and efficacy profile of the program and guide future development decisions.2
As of February 27, 2026, the company has dosed 68 patients in the randomized Hero study along with 19 patients in the extension trial.
The Hero study was a Phase III,double blind study sponsored by Aardvark Therapeutics to investigate the effects of ARD-101 on hyperphagia-related behavior in people with Prader-Willi Syndrome.2 This study is designed to compare ARD-101 to a placebo to identify if ARD-101 works to treat hyperphagia in PWS.2
Despite the clinical hold, Aardvark says it maintains sufficient financial resources to continue operations while assessing next steps. According to a report from Reuters, the company reported $91.2 million in cash and investments as of March 31, 2026, which it expects will fund operations into mid-2027.2
FDA’s decision adds to broader scrutiny around safety monitoring in metabolic disease drug development, particularly as companies pursue therapies targeting appetite regulation and gut signaling pathways.
Sources
- Aardvark Therapeutics Plans to Unblind HERO and OLE Data to Inform Path Forward Following FDA Clinical Hold Aardvark Therapeutics May 14, 2026
https://ir.aardvarktherapeutics.com/news-releases/news-release-details/aardvark-therapeutics-plans-unblind-hero-and-ole-data-inform - FDA places full clinical hold on Aardvark's drug for extreme hunger in Prader-Willi syndrome Reuters May 14, 2026
https://www.reuters.com/business/healthcare-pharmaceuticals/fda-places-full-clinical-hold-aardvarks-drug-extreme-hunger-prader-willi-2026-05-14/
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