Sapropterin for a child with multisystem smooth muscle dysfunction syndrome
Official title: A Single Patient Study (SPS) of Sapropterin for Multisystem Smooth Muscle Dysfunction Syndrome (MSMDS).
Run by St. Justine's Hospital · NCT07574034 · Data updated 2026-11-12
This single-patient study in Canada tests whether sapropterin can help a child with MSMDS caused by an ACTA2 gene variant.
Quick facts
| Study type | Interventional |
|---|---|
| Ages | 1 Month to 18 Years |
| Sex | All |
| Enrollment | 1 (estimated) |
| Sponsor | St. Justine's Hospital Academic / other |
| Locations | 1 site (Montreal, Quebec) |
| Status | Recruiting |
| Started | July 15, 2026 |
| Main results expected | June 1, 2028 |
| Study ends | June 1, 2030 |
| Registry record updated | November 5, 2026 |
| Trial ID | NCT07574034 on ClinicalTrials.gov |
Is this trial a fit for you?
✓Likely a good fit
Ideal candidates are children aged 1 month to 18 years with the ACTA2 p.Arg179His variant and no prior Kuvan exposure or contraindications.
✕Probably not a fit
Patients with hypersensitivity to sapropterin, active nitric oxide–related medications, or conditions that increase risk or complicate participation may not benefit.
A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.
What this trial studies
This is a single-patient, interventional study in a child with multisystem smooth muscle dysfunction syndrome (MSMDS). Sapropterin (Kuvan) is repurposed for this use, given its role as a cofactor in metabolic pathways and prior animal model promise for MSMDS. The study aims to gather data on safety and signals of benefit to support potential future approval for this indication. Eligibility requires confirmed ACTA2 p.Arg179His and age 1 month to 18 years, with several exclusion criteria to minimize risk. The trial is conducted at CHU Sainte-Justine in Montreal under the lead sponsorship of Gregor Andelfinger.
Why it matters
Potential benefit: If successful, the patient could experience improved smooth muscle function and access to a therapy that targets the underlying mechanism of MSMDS.
How similar studies have gone: There have been animal-model signals and prior repurposing strategies for MSMDS, but this exact pediatric human study is novel and exploratory.
Who can join: the full rules
Show full inclusion / exclusion criteria
Inclusion Criteria: * Patients with the following molecularly confirmed genotype: ACTA2 c.536G\>A, p.Arg179His * Aged 1 month to 18 years Exclusion Criteria: * Previous exposure to Kuvan®, Biopten®, or any preparation of tetrahydrobiopterin for greater * Known hypersensitivity to Kuvan® or its excipients * Known hypersensitivity to other approved or non-approved formulations of tetrahydrobiopterin * Current use of medications that are known to affect nitric oxide synthesis, metabolism or action * Current use of experimental/other investigational or unregistered drugs that may affect the study outcomes * Inability to comply with study procedures * Concurrent disease or condition that would interfere with study participation or increase the risk for adverse events, including stroke, renal or hepatic failure * Other significant disease that in the Investigator's opinion would exclude the subject from the trial * Any condition that, in the view of the Principal Investigator renders the subject at high risk for failure to comply with treatment or to complete the study
Where it's running
-
CHU Sainte-Justine
Montreal, Quebec, Canada Recruiting
Similar studies
Other studies for the same condition or treatment. Recruiting studies are listed first.
-
Observing the natural history of genetic vasculopathies in patients with ACTA2 mutations
This study looks at how ACTA2 gene mutations affect people over time to better understand the condition and its progression.
-
Arm versus ankle mean arterial pressure during elective cesarean delivery
This study will see if a blood pressure cuff on the ankle gives similar mean arterial pressure readings to a standard arm cuff in pregnant people having a planned C-section under spinal anesthesia.
-
Using virtual reality to help with diagnostic hysteroscopy
This study tests whether immersive virtual reality or Hypno-VR can reduce pain and anxiety for adults undergoing diagnostic hysteroscopy.
-
Adjusting hydroxyurea dose using pharmacokinetics in children with sickle cell disease
This study tests whether using pharmacokinetic testing to guide hydroxyurea dosing helps kids with sickle cell disease reach the maximum tolerated dose faster than standard blood testing alone.
-
Mirdametinib plus vinblastine for newly diagnosed pediatric low-grade glioma with MAPK activation
This trial will test whether giving oral mirdametinib together with weekly vinblastine helps children and young adults (ages 2–25) with newly diagnosed low-grade glioma that shows MAPK pathway activation.
-
Smoking cessation for parents with health navigator support to tackle social needs
We’re testing a program that helps parents quit smoking and also addresses their social challenges to reduce kids’ exposure to secondhand smoke.
How to take part
- Review the eligibility criteria above with your treating physician.
- Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
- Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.