NCT05918211 · Mezzion Pharma Co. Ltd
Fontan Udenafil Exercise Longitudinal Assessment Trial - 2
(FUEL-2)
What this study is about
This study will evaluate the clinical effectiveness and safety of udenafil, an taken by mouth administered, potent and selective inhibitor of PDE5, versus placebo for the treatment of adolescent who have had the Fontan procedure.
View original scientific description
This study will evaluate the clinical efficacy and safety of udenafil, an orally administered, potent and selective inhibitor of PDE5, versus placebo for the treatment of adolescent who have had the Fontan procedure.
Interventions
DRUG
Udenafil
Active drug
DRUG
Placebo
Matching Placebo
Primary outcome measures
Change in Exercise Capacity
Time frame: Baseline to 26 Weeks
The change in exercise capacity (as measured by maximal VO2 at maximum exercise effort) from baseline to 26 weeks (or study completion)
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- Males and females with Fontan physiology who are 12 to less than 19 years of age at enrollment. 2. Participant consent or parental/guardian consent and participant assent. 3. Participant fluency in primary language of country in which study is being conducted. 4. Current antiplatelet or anticoagulant therapy.
Exclusion criteria
- Height \< 132 cm. 2. Weight \< 40 kg. 3. Hospitalization for acute decompensated heart failure within the last 12 months. 4. Current intravenous inotropic drugs. 5. Undergoing evaluation for heart transplantation or listed for transplantation. 6. Diagnosis of active protein losing enteropathy or plastic bronchitis within the last 3 years, or a history of liver cirrhosis. 7. Known Fontan baffle obstruction, branch pulmonary artery stenosis, or pulmonary vein stenosis resulting in a mean gradient of \> 4 mmHg between the regions proximal and distal to the obstruction as measured by either catheterization or echocardiography, obtained
Where
- Phoenix, Arizona
- Little Rock, Arkansas
- Los Angeles, California
- San Diego, California
- San Francisco, California
- Denver, Colorado
- New Haven, Connecticut
- Wilmington, Delaware
- Washington D.C., District of Columbia
- Gainesville, Florida
- Hollywood, Florida
- St. Petersburg, Florida
And 23 more locations — see the full list below.
Related conditions & keywords
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Oct 28, 2025 · Source of record for eligibility and locations