FDA places full clinical hold on Aardvark Prader-Willi

Aardvark Therapeutics said on May 14 that the U.S. Food and Drug Administration placed a full clinical hold on ARD-101, the company’s lead program for hyperphagia in Prader-Willi syndrome. The hold applies to all ongoing studies under the drug’s investigational new drug application, including the Phase 3 HERO trial and its open-label extension, the company said. The decision follows a voluntary pause Aardvark announced earlier this year after cardiac findings emerged in a separate healthy-volunteer study. Chief Executive Tien Lee said the company is in active discussions with the FDA and plans to unblind accumulated trial data to help determine a path forward. ### Which studies are now on hold? The May 14 hold covers the Phase 3 HERO trial, listed as AVK-101-301, and the Phase 3 open-label extension trial, AVK-101-302, Aardvark said. HERO was testing ARD-101 for hyperphagia in patients with Prader-Willi syndrome, a rare genetic disorder marked by chronic, intense hunger, according to the company and ClinicalTrials.gov. (financialcontent.com) ClinicalTrials.gov lists the open-label extension as suspended and says the study had an estimated enrollment of 90 patients across 30 U.S. locations, with estimated primary completion in March 2027. The federal registry says the pause was tied to reversible cardiac observations at above-target therapeutic doses in a healthy-volunteer study. (financialcontent.com) ### What did Aardvark say triggered the safety review? Aardvark had already paused enrollment and dosing in February after what it described as unexpected reversible cardiac observations in a separate healthy-volunteer study. The company said at the time that the findings were seen at above-target therapeutic doses and that it was reviewing the data before deciding next steps. (clinicaltrials.gov) Fierce Biotech reported that the earlier review centered on QRS prolongation, a change in cardiac conduction seen in healthy volunteers, and said the signal emerged in dosing above the regimen used in the Prader-Willi study. Reuters reported on May 14 that the FDA’s full hold halted all late-stage trials of the drug. (biospace.com) ### How far had the Prader-Willi program progressed? As of February 27, Aardvark said it had dosed 68 patients in the randomized HERO trial and 19 patients in the open-label extension. The company said those data will now be unblinded so it can review both efficacy and safety across the program. (fiercebiotech.com) Before the pause, Aardvark had expected topline data from the Phase 3 study in the third quarter of 2026, according to Fierce Biotech. That timetable is no longer in place while the hold remains active. ### What exactly is Aardvark doing next? Tien Lee said on May 14 that Aardvark is “continuing to work collaboratively” with the FDA to evaluate the data and determine the best path forward for ARD-101. (financialcontent.com) The company said it intends to unblind data from both HERO and the extension trial in parallel with its regulatory discussions. (fiercebiotech.com) MarketWatch reported that Aardvark said the unblinded review would help it assess efficacy and safety and decide the next steps for the program. Reuters said the company’s shares fell about 14% in after-hours trading after the announcement, while Fierce Biotech reported a 16% drop to $5.65 after hours. (financialcontent.com) ### What does this mean for Aardvark’s finances and timeline? Aardvark said on May 14 that it had $91.2 million in cash, cash equivalents and short-term investments as of March 31 and believes that is enough to fund operations into mid-2027. The company had said a week earlier that it expected to provide further guidance on ARD-101 in the second quarter of 2026. (marketwatch.com) The next concrete milestones are the company’s unblinded review of HERO and open-label extension data and its ongoing talks with the FDA over what information is needed to lift the hold. Aardvark has not given a date for either step, but said on May 14 that both are now underway. (financialcontent.com)