Existing Phase 3 Trial Halted and Clinical Hold Prolonged

Aardvark Therapeutics (AARD) has terminated its Phase 3 HERO trial and open-label extension (OLE) study for ARD-101, a treatment for hyperphagia associated with Prader-Willi Syndrome (PWS). The company clarified that it is not abandoning ARD-101 entirely but intends to analyze interim data in a blinded manner and collaborate with the FDA on a new development pathway. The FDA issued a full clinical hold on the ARD-101 clinical trial on May 14, 2026, escalating from a voluntary pause in dosing in February. With the pivotal trial discontinued, restarting will require additional safety testing or modifications to the dosage and protocol, increasing both the development timeline and financial burden.

Cardiac Signals Alter Risk-Benefit Profile

ARD-101 is an oral, small-molecule agonist of the TAS2R2 taste receptor, developed under a generic name, that stimulates TAS2R in the gut to activate satiety signals such as PYY and GLP-1. In a healthy volunteer cardiac safety study, two out of eight subjects in the 1,600mg twice-daily dose group exhibited a QRS interval increase of more than 25% compared to baseline, with an additional subject showing an increase of less than 25%. While similar cardiac signals were not observed in previous Phase 1 and 2 trials or non-clinical studies, the detection of conduction abnormalities in a formal cardiac assessment conducted to support the marketing application has heightened regulatory risks. The blinded data from the HERO (68 subjects) and OLE (19 subjects) studies will serve as critical evidence to determine whether the efficacy and safety at the therapeutic dose justify a new clinical design.

ARD-201 Development Suspended and Cost Structure Reduced

ARD-201, a fixed-dose combination of ARD-101 and a DPP-4 inhibitor, has also seen the suspension of Phase 2 development for obesity and weight regain in the POWER and STRENGTH trials. Addressing the cardiac safety concerns of the parent compound is a prerequisite for proceeding with the combination therapy, meaning that a single safety issue has impacted both the PWS and obesity pipelines. The company implemented a workforce reduction in June 2026, decreasing its staff from 40 employees and 35 consultants at the end of April to 28 employees and 27 consultants by the end of July. By reducing clinical operating expenses, the company has extended its cash runway to the second half of 2027; however, the reduction in late-stage clinical and regulatory personnel has increased the execution burden of redesigning the program.

Commercial Advantage of Approved Competing Drug Expands

Currently, the primary competing drug is Soleno Therapeutics' (SLNO) VYKAT XR (diazoxide choline extended-release), a sustained-release formulation that modulates ATP-sensitive potassium channels (KATP channels). The FDA approved VYKAT XR on March 26, 2025, for the treatment of hyperphagia in patients aged four years and older with PWS, with orphan drug exclusivity extending to March 2032. The product generated net sales of $190.4 million in 2025, following its launch in the second quarter of 2025, and the PWS treatment market was estimated at $682.6 million in 2025. While growth hormone and behavioral/dietary management are used to improve growth and body composition, they are not approved as direct treatments for hyperphagia, making the delay of ARD-101 further solidify VYKAT XR's first-mover advantage and patient conversion barrier.