Peer-reviewed publication advances understanding of Fontan-associated liver disease (FALD) and adds to the growing body of evidence supporting udenafil in Fontan circulation

FORT LEE, N.J., July 16, 2026 /PRNewswire/ -- Mezzion Pharmaceuticals today announced publication of "The FUEL FALD Study: Effects of Udenafil on Liver Stiffness and Fibrosis after Fontan" in the peer-reviewed journal Pediatric Cardiology. The publication reports findings from an exploratory substudy of the FUEL Open Label Extension (OLE) evaluating Fontan-associated liver disease (FALD) in adolescents and young adults who received 12 months of udenafil treatment.

As survival following the Fontan procedure has improved, FALD has emerged as one of the most important long-term complications affecting patients living with Fontan circulation. Driven by the unique Fontan physiology, FALD is characterized by progressive liver injury and fibrosis and remains an area of significant unmet medical need, with no approved therapies specifically indicated for this condition.

The publication highlights the substantial burden of liver disease in this population. At study entry, 95% of participants had elevated Enhanced Liver Fibrosis (ELF) scores, consistent with at least moderate fibrosis based on thresholds established in other liver diseases. Liver stiffness was also assessed using ultrasound shear wave elastography (SWE) and magnetic resonance elastography (MRE) .

Following 12 months of udenafil treatment, investigators observed a significant decrease in the ELF score, a non-invasive biomarker associated with fibrotic remodeling, with 84% of participants demonstrating a reduction over the study period. Although liver stiffness measurements did not significantly change, the authors concluded that the findings suggest the possibility that udenafil may alter the overall Fontan fibrotic milieu and warrant further study.

The publication adds to a growing body of peer-reviewed evidence from the FUEL clinical program examining udenafil across multiple dimensions of Fontan physiology, including exercise capacity, ventricular performance, cardiovascular safety, nitric oxide pathway biology, patient experience, and liver fibrosis biomarkers.

"As patients with Fontan circulation continue to live longer, understanding and addressing the long-term complications of Fontan physiology has become increasingly important," said Kurt Schumacher, M.D., Chief of Pediatric Cardiology at University of Michigan Health C.S. Mott Children's Hospital and lead author of the publication. "These findings contribute to our growing understanding of Fontan-associated liver disease and reinforce the importance of continuing to investigate therapies that may address this serious long-term complication."

"Fontan-associated liver disease is one of the most serious long-term complications of Fontan circulation, and patients and clinicians have very limited options to address it." said Ridwan Shabsigh, M.D., F.A.C.S, President and COO of Mezzion, "The FUEL FALD Study provides important new insight into the potential role of udenafil in the fibrotic process associated with Fontan physiology and supports continued investigation of this complex disease."

"The breadth of research emerging from the FUEL program is providing increasingly comprehensive view of Fontan physiology and the potential role of udenafil," said Dean Park, Chairman and CEO of Mezzion. " As we advance through the final phase of enrollment in the confirmatory Phase 3 FUEL-2 trial, we remain focused on developing the first therapy specifically indicated for patients living with Fontan circulation."

Mezzion gratefully acknowledges the patients and families who participated in the FUEL clinical program, the investigators and participating clinical sites, and the Pediatric Heart Network for their contributions to advancing research in Fontan circulation.

About the FUEL-2 Trial

FUEL-2 is Mezzion's global confirmatory Phase 3 trial evaluating udenafil in adolescents and young adults with Fontan circulation. The study is designed to evaluate exercise capacity and support potential regulatory approval of udenafil as the first therapy specifically developed for patients living with Fontan circulation. Learn more at www.FUEL2Study.com.

Publication

The full publication is available in Pediatric Cardiology: https://doi.org/10.1007/s00246-026-04334-9

About Mezzion Pharmaceuticals

Mezzion Pharmaceuticals is a clinical-stage biopharmaceutical company developing therapies for rare cardiovascular and renal diseases. Its lead investigational product, udenafil, is being evaluated in the global Phase 3 FUEL-2 trial for single ventricle congenital heart disease patients living with Fontan circulation. Mezzion Pharmaceuticals is the U.S. subsidiary of Mezzion Pharma Co., Ltd. (KOSDAQ: 140410). Learn more at www.mezzion.com.

Forward-Looking Statements

This press release contains forward-looking statements regarding the future development of Mezzion's investigational product candidates, including statements relating to the clinical development of udenafil, the FUEL-2 trial, regulatory interactions, potential regulatory approvals, future research, and anticipated clinical outcomes. These forward-looking statements are based on current expectations and assumptions and are subject to risks and uncertainties that could cause actual results to differ materially from those expressed or implied. Mezzion undertakes no obligation to update any forward-looking statements except as required by applicable law.

Media & Investor Contacts

John Presser
Executive Vice President & Chief Business Officer
john.presser@mezzion.com 

Sung-Il Noh
Chief Financial Officer
sung-il.noh@mezzion.com 

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SOURCE Mezzion Pharmaceuticals, Inc