Aardvark Therapeutics wins FDA lift of ARD-101 clinical hold

The FDA has cleared Aardvark's IND for ARD-101 in Prader-Willi Syndrome after cardiac safety studies found no events at therapeutic doses.

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Aardvark Therapeutics has confirmed that the US Food and Drug Administration has lifted the clinical hold on its investigational new drug application for ARD-101, an oral small-molecule candidate being developed to treat hyperphagia in Prader-Willi Syndrome (PWS). The San Diego-based company said clinical development may now resume, pending further alignment with the FDA on a revised Phase 3 trial design.

The hold originated after Aardvark voluntarily paused dosing in its Phase 3 HERO trial and an associated open-label extension (OLE) in February 2026, following reversible electrocardiogram changes spotted during routine safety monitoring in healthy volunteers enrolled in a separate study. The FDA formally placed the hold in May 2026. To satisfy the agency's requirements, Aardvark completed a dedicated ECG study in additional healthy volunteers and an in vitro cardiac sodium channel (NaV1.5) assay. No cardiac events were observed at ARD-101 doses of 200 mg and 400 mg twice daily in the new ECG work.

Mechanism and background

ARD-101 is designed to stimulate gut-peptide hormone release through activation of bitter taste receptors, a pathway distinct from the appetite-reward circuitry targeted by GLP-1 receptor agonists. Aardvark frames this as addressing hunger, defined as the discomfort arising from food deprivation, rather than the reward-seeking component of eating behaviour. PWS is a rare genetic disorder characterised by insatiable hunger that can lead to life-threatening obesity, and currently has no approved pharmacological treatment specifically targeting hyperphagia.

The HERO trial was terminated early, and Aardvark has since unblinded the accumulated efficacy and safety data from both the HERO and OLE studies. The company plans to host an investor webcast on 23 October 2026 to review that dataset. The company's own disclosures note that neither trial was powered to assess efficacy, so any efficacy signals from the unblinded data should be treated as exploratory. A redesigned Phase 3 programme will require further FDA agreement before it can commence.

Market and competitive context

The PWS space has attracted growing interest from developers targeting central and peripheral hunger pathways. Several companies have explored melanocortin receptor agonists and oxytocin analogues in the indication, with mixed results, underlining the difficulty of the biology. The recent commercial success of GLP-1 agonists in broader obesity has raised the profile of hunger-targeting programmes, though PWS represents a distinct and more complex regulatory challenge given the rarity of the condition, the vulnerability of the patient population, and the heightened safety scrutiny that regulators typically apply.

Aardvark's resolution of the cardiac safety question through dedicated electrophysiology work is a meaningful step, but the path to a pivotal trial remains contingent on agreeing a new study design with the FDA. Founder and chief executive Tien Lee said the company had completed "the work necessary to allow for the resumption of clinical studies" and looked forward to continuing to advance ARD-101. Investors will focus on the webcast data review and the timeline for formal FDA feedback on Phase 3 design as the next key catalysts for the programme.

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