A Single Patient Study of Sapropterin for Multisystem Smooth Muscle Dysfunction Syndrome

NCT07574034 | Not Yet Recruiting

• 1 other identifier: SPS-MSMDS
• Study Type: interventional
• Target: 1
• Locations: 1 country
• Sites: 1

Brief Summary

There is currently no approved treatment for multisystem smooth muscle dysfunction syndrome (MSMDS). This single-patient study is the first to be conducted in a child with MSMDS in Canada and was designed to provide the child with access to sapropterin treatment. The molecule we will be using, sapropterin (Kuvan), is already approved and available for other indications. This disease is caused by a genetic variant in the ACTA2 gene. This variant prevents the small units of actin fibers, which are the molecular motors of the smooth muscle cell, from assembling correctly. The goal is to gather data so that the drug can be approved for this indication and thus treat the patient.

Conditions

Multisystemic Smooth Muscle Dysfunction Syndrome

Keywords

multisystemic smooth muscle dysfunction syndrome; MSMDS; Sapropterine; Kuvan

Outcome Measures

Primary Outcomes (4)

• Crossing of percentile of growth

  2 years

• Increase of mean diastolic blood pressure by more than 8 mmHg

  2 years

• Absence of cerebral vascular complications

  2 years

• Absence of progression of cerebral vascular disease

  2 years

Study Arms (1)

Open label Intervention

EXPERIMENTAL

Participant will receive KUVAN® (sapropterin dihydrochloride) 100 mg Powder Packets once daily.

Drug: Kuvan (Sapropterine)

Interventions

Kuvan (Sapropterine) DRUG

Sapropterine is already approved in Canada for the treatment of phenylketonuria (PKU) and has shown promise as an agent against multisystem smooth muscle dysfunction syndrome (MSMS) in an animal model. No clinical trials are currently underway with sapropteride for MSMS.

Open label Intervention

Eligibility Criteria

• Age: 1 Month - 18 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Child (0-17), Adult (18-64)

You may qualify if:

• Patients with the following molecularly confirmed genotype: ACTA2 c.536G\>A, p.Arg179His
• Aged 1 month to 18 years

You may not qualify if:

• 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

Sponsors & Collaborators

• Gregor Andelfinger: lead

Study Sites (1)

CHU Sainte-Justine

Montreal, Quebec, H3T 1C5, Canada

Location

Related Publications (1)

• Krishnan V, Rahman A, Das S, Weil M, Altman S, Shamber C, Fong CT, Goldstein AM, Lindsay ME, Musolino P. A novel drug Sapropterin (Kuvan) ameliorates the disease phenotype in a mouse model of multisystem smooth muscle dysfunction syndrome. Child Neurology Society Meeting Vancouver. 2023.

  BACKGROUND

MeSH Terms

Interventions

sapropterin

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NA
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: SPONSOR INVESTIGATOR
• PI Title: Pediatric Cardiologist

Model Details: This is a single patient study (SPS)

Study Record Dates

• First Submitted: May 1, 2026
• First Posted: May 7, 2026
• Study Start (Estimated): June 1, 2026
• Primary Completion (Estimated): June 1, 2028
• Study Completion (Estimated): June 1, 2030
• Last Updated: May 7, 2026

Record last verified: 2026-03

Data Sharing

• IPD Sharing: Will not share

Locations

CA (1)