Last month, we shared that Aardvark Therapeutics announced a voluntary pause in enrollment and dosing for the Phase 3 HERO clinical trial evaluating ARD-101 for hyperphagia in individuals with Prader-Willi syndrome (PWS).
In a new update, Aardvark has provided additional details to help explain this decision and outline next steps.
According to the announcement shared on March 23, 2026, the pause followed observations in a separate healthy volunteer study (not involving individuals with PWS) that was conducted as part of routine cardiac safety testing. In this study, some participants experienced changes in a heart measurement known as QRS duration at higher dose levels.
Importantly, Aardvark shared that:
– These observations were not seen in prior Phase 1 or Phase 2 trials involving individuals with PWS
– The findings were not associated with serious symptoms
– The changes were reversible after stopping the medication and did not require medical intervention
The company is continuing a comprehensive review of the data and is working closely with the U.S. Food and Drug Administration to determine the most appropriate path forward.
“Patient safety will always be our highest priority, and we are actively engaging with the FDA with urgency to determine the best path forward for our programs. As we evaluate next steps, we want to thank the Prader-Willi Syndrome community for its collaboration throughout this process. The community’s strength and tenacity continue to inspire our work. With positive clinical data, an encouraging safety profile from previous trials and our recently developed understanding of the clear blood plasma exposure-response relationship with reversible cardiac QRS prolongation, we have confidence in ARD-101. We strongly believe that ARD-101 retains its potential as a differentiated therapeutic option for hyperphagia in individuals living with PWS. We hope to resume the PWS development program in a timely manner and expect to provide further guidance on each of our programs in the second quarter of 2026.”
At this time, the HERO trial remains paused while Aardvark continues its evaluation and discussions with regulators. The company has expressed its intention to provide additional updates in the second quarter of 2026.
As always, PWSA | USA is committed to keeping our community informed and supported. We will continue to share updates as more information becomes available.
Read Aardvark’s full press release at the button below.
Perry A. Zirkel has written more than 1,500 publications on various aspects of school law, with an emphasis on legal issues in special education. He writes a regular column for NAESP’s Principal magazine and NASP’s Communiqué newsletter, and he did so previously for Phi Delta Kappan and Teaching Exceptional Children.
Jennifer Bolander has been serving as a Special Education Specialist for PWSA (USA) since October of 2015. She is a graduate of John Carroll University and lives in Ohio with her husband Brad and daughters Kate (17), and Sophia (13) who was born with PWS.
Dr. Amy McTighe is the PWS Program Manager and Inpatient Teacher at the Center for Prader-Willi Syndrome at the Children’s Institute of Pittsburgh. She graduated from Duquesne University receiving her Bachelor’s and Master’s degree in Education with a focus on elementary education, special education, and language arts.
Evan has worked with the Prader-Willi Syndrome Association (USA) since 2007 primarily as a Crisis Intervention and Family Support Counselor. Evans works with parents and schools to foster strong collaborative relationships and appropriate educational environments for students with PWS.
Staci Zimmerman works for Prader-Willi Syndrome Association of Colorado as an Individualized Education Program (IEP) consultant. Staci collaborates with the PWS multi-disciplinary clinic at the Children’s Hospital in Denver supporting families and school districts around the United States with their child’s Individual Educational Plan.
Founded in 2001, SDLC is a non-profit legal services organization dedicated to protecting and advancing the legal rights of people with disabilities throughout the South. It partners with the Southern Poverty Law Center, Protection and Advocacy (P&A) programs, Legal Services Corporations (LSC) and disability organizations on major, systemic disability rights issues involving the Individuals with Disabilities Education Act (IDEA), Americans with Disabilities Act (ADA), and the federal Medicaid Act. Recently in November 2014, Jim retired.