Open-Label Extension Study of Diazoxide Choline in Patients With Prader-Willi Syndrome


The purpose of this is study is to evaluate the long term safety of DCCR (diazoxide choline controlled release tablets) in children and adults with Prader-Willi syndrome. After completion of 1 year in this study, subjects will have the option to continue treatment for up to 2 additional years.

Full Title of Study: “An Open-Label, Long-Term Safety Evaluation of Diazoxide Choline Controlled-Release Tablet in Patients With Prader-Willi Syndrome”

Study Type

  • Study Type: Interventional
  • Study Design
    • Allocation: N/A
    • Intervention Model: Single Group Assignment
    • Primary Purpose: Treatment
    • Masking: None (Open Label)
  • Study Primary Completion Date: April 2021


  • Drug: DCCR
    • Once daily oral administration

Arms, Groups and Cohorts

  • Experimental: DCCR
    • 75 – 450 mg DCCR

Clinical Trial Outcome Measures

Primary Measures

  • Assess the safety of DCCR by evaluating the incidence and severity of adverse events reported
    • Time Frame: Baseline to Week 54 or until resolution of certain adverse events at the discretion of the Investigator and Sponsor
    • Safety analyses will be conducted in all subjects who receive at least one dose of DCCR. Adverse events will be described by type and level of severity.

Secondary Measures

  • Hyperphagia Score
    • Time Frame: Baseline to Week 52
    • Hyperphagia-related behaviors will be assessed by the hyperphagia questionnaire for clinical trials (HQ-CT), an instrument designed to measure symptoms of food related preoccupations and behaviors. The HQ-CT consists of nine items with responses ranging from 0-4 (best to worst). Scores from 9 items will be summed for a possible total score range of 0-36.
  • Body fat mass (DXA)
    • Time Frame: Baseline at Week 52
    • Change in Body Fat Mass from Baseline to Week 52
  • Clinical Global Impression of Improvement (CGI-I)
    • Time Frame: at Week 52
    • CGI-I is a single statement designed to assess the Investigator’s overall perception of change in the subject’s condition across the course of the clinical trial. The Investigator provides a response to “Compared to the subject’s condition at enrollment, the subject’s condition is:” by rating the subject’s behavior using a 7-point response scale (best to worst).
  • Caregiver Global Impression of Change (Caregiver GI-C)
    • Time Frame: at Week 52
    • The Caregiver GI-C is a single statement designed to assess the caregiver’s overall perception of change in the subject across the course of the clinical trial. The caregiver provides a response to “Please choose the response below that best describes the overall change in the person’s PWS since they started taking the study medication” using a 7-point graded response scale (best to worst).

Participating in This Clinical Trial

Key Inclusion Criteria:

  • Successful completion of clinical study C601
  • Provide voluntary, written informed consent (parent(s) / legal guardian(s) of patient); provide voluntary, written assent (subjects, as appropriate)

Key Exclusion Criteria:

  • Positive urine pregnancy test (in females of child-bearing potential) or females who are pregnant or breastfeeding, and/or plan to become pregnant or to breast-feed during or within 90 days after study participation
  • Any new disease, condition, or circumstance which would prevent, in the opinion of the Investigator, the patient from completing all study visits and assessments required by the protocol (e.g., an anticipated change of care setting)

Gender Eligibility: All

Minimum Age: 4 Years

Maximum Age: N/A

Are Healthy Volunteers Accepted: No

Investigator Details

  • Lead Sponsor
    • Soleno Therapeutics, Inc.
  • Provider of Information About this Clinical Study
    • Sponsor

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