Growth hormone trial aims to boost muscle in Prader-Willi patients
NCT ID NCT04697381
First seen Jun 27, 2026 · Last updated Jun 27, 2026
Summary
This completed Phase 3 study tested somatropin, a synthetic growth hormone, in 33 Japanese children and adults with Prader-Willi syndrome. The goal was to see if it safely improves body composition by increasing lean body mass and reducing fat. Participants were divided into three groups based on age and prior growth hormone use, and changes were measured over 12 months.
What this could mean
Our plain-language read of the trial. This is informational only, not medical advice or a prediction.
- Active substance
- somatropin (a synthetic growth hormone)
- What this could lead to
- If successful, this could confirm somatropin as a safe and effective way to improve body composition (more lean muscle, less fat) in people with Prader-Willi syndrome.
- What could go wrong
- This is a small, open-label study (no placebo group) in Japanese participants only, so results may not apply broadly. Growth hormone therapy has known side effects like joint pain and swelling.
This is an AI summary of the original study and may miss details. Read our disclaimer.
Study facts
What this study's own registry entry says, in plain language.
- Phase
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Phase 3
Large-scale testing in a bigger group. Usually the last step before a treatment can be approved.
- Participants
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33 people
The number who actually took part.
- Started
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Feb 2021
- Finished
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Apr 2024
- Lead sponsor
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A company
The lead sponsor is a pharmaceutical, biotech, or medical-device company.
Who can take part
This study's own entry requirements. Only the study team can say for certain whether you qualify.
- Ages
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0 years and older
- Sex
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Anyone
- Healthy volunteers
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Not accepted
This study is not open to healthy volunteers. The entry requirements below say who it is open to.
Show the full entry requirements Hide the full entry requirements
Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.
Inclusion Criteria: 1. Male or female participants with documentation of genetically confirmed diagnosis of PWS. 2. No plan to initiate a new treatment that may affect the body composition, such as gonadal hormone replacement therapy. 3. Currently on appropriate diet and exercise programs and willing to continue throughout the study period at the discretion of the investigator. 4. Participants, and if required by local/site regulations their parent(s)/legal guardian(s) must be willing and able to comply with all scheduled visits, treatment plan, laboratory tests, lifestyle considerations, and other study procedures. 5. Evidence of a personally signed and dated ICD (and written assent where applicable based on age and country regulation) indicating that the participant or a legally acceptable representative/parent(s)/legal guardian has been informed of all pertinent aspects of the study. Refer to Appendix 1 for the detailed process of obtaining consent. For inclusion of GH naïve pediatric cohort, participants must meet criteria 6 to 8: 6. 18 years or younger. 7. Naïve to GH treatment. 8. Tanner stage 1 (for testes in males, for breasts in females). For inclusion of GH treated pediatric cohort, participants must meet criteria 9 and 10: 9. Continued GH treatment for at least 2 years with stable dose for the last 6 months and being on GH at time of inclusion. The recent dose should be higher than 0.084 mg/kg/week. 10. Participants who are about to complete GH treatment for his/her short stature (eg, due to meeting the treatment stopping criteria defined as a height SDS more than -2.5 for Japanese adult standards). For inclusion of adult cohort, participants must meet criteria 11 to 13: 11. 18 years of chronological age or older at Day 1 visit. 12. Off from GH treatment for at least 1 year. 13. Serum IGF-I level within +2 SDS, adjusted for age and sex. Exclusion Criteria: 1. Participants with uncontrolled diabetes at the discretion of the investigator. 2. Participants with malignant tumors. 3. Participants with severe obesity or serious respiratory impairment. 4. Other medical or psychiatric condition including recent (within the past year) or active suicidal ideation/behavior or laboratory abnormality that may increase the risk of study participation or, in the investigator's judgment, make the participant inappropriate for the study. 5. Previous administration with an investigational drug within 30 days (or as determined by the local requirement) or 5 half- lives preceding the first dose of study intervention used in this study (whichever is longer). 6. Investigator site staff or Pfizer employees directly involved in the conduct of the study, site staff otherwise supervised by the investigator, and their respective family members.
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Conditions
The condition(s) this trial relates to.
As listed by the trial registrant
The condition terms exactly as the trial's registrant entered them.
Contacts and locations
Locations
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Dokkyo Medical University Saitama Medical Center
Koshigaya, Saitama, 343-8555, Japan
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Hamamatsu University Hospital
Hamamatsu, Shizuoka, 431-3192, Japan
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Kanagawa Children's Medical Center
Yokohama, Kanagawa, 232-8555, Japan
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National Center for Child Health and Development
Setagaya-ku, Tokyo, 157-8535, Japan
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Osaka Women's and Children's Hospital
Izumi, Osaka, 594-1101, Japan
More trials for these conditions
Other studies related to the condition(s) this trial covers.
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- Can early parent coaching help infants with rare genetic disorders thrive?
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- New group therapy aims to tame meltdowns in Prader-Willi teens