Study of the Efficacy and Safety of Somatropin in Japanese Participants With PWS

December 23, 2025 updated by: Pfizer

A PHASE 3 MULTICENTER, OPEN LABEL, MULTI COHORT STUDY TO EVALUATE THE EFFICACY AND SAFETY OF SOMATROPIN IN JAPANESE PARTICIPANTS WITH PRADER-WILLI SYNDROME (PWS)

This is a multicenter, open label, multi cohort study to evaluate the efficacy and safety of somatropin in a cohort of Japanese participants with PWS.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
33

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 3

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Japan
    • Kanagawa
      • Yokohama, Kanagawa, Japan, 232-8555
        • Kanagawa Children's Medical Center
    • Osaka
      • Izumi, Osaka, Japan, 594-1101
        • Osaka Women's and Children's Hospital
    • Saitama
      • Koshigaya, Saitama, Japan, 343-8555
        • Dokkyo Medical University Saitama Medical Center
    • Shizuoka
      • Hamamatsu, Shizuoka, Japan, 431-3192
        • Hamamatsu University Hospital
    • Tokyo
      • Setagaya-ku, Tokyo, Japan, 157-8535
        • National Center for Child Health and Development

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

1 second and older (Child, Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

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.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Non-Randomized
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: somatropin - GH naïve pediatric cohort
All participants will receive somatropin.
Biological: somatropin - GH naïve pediatric cohort
somatropin 0.245 mg/kg/week
Experimental: somatropin - GH treated pediatric cohort
All participants will receive somatropin
Biological: somatropin - GH treated cohort
somatropin 0.084 mg/kg/week
Experimental: somatropin - adult cohort
All participants will receive somatropin
Biological: somatropin - adult cohort
somatropin 0.084 mg/kg/week

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Change From Baseline to Month 12 in Lean Body Mass Measured by DEXA: GH Naive Pediatric and GH Treated Pediatric Cohort
Time Frame: Baseline, Month 12
Lean body mass, a measurement of body composition, was assessed by DEXA scan, and calculated as lean body mass (%) = lean body mass (kg) / (lean body mass [kg] + fat mass [kg])*100.
Baseline, Month 12
Change From Baseline to Month 12 in Lean Body Mass Measured by Dual-Energy X-ray Absorptiometry (DEXA): Adult Cohort
Time Frame: Baseline, Month 12
Lean body mass, a measurement of body composition, was assessed by DEXA scan, and calculated as lean body mass (%) = lean body mass kilogram (kg) / (lean body mass [kg] + fat mass [kg]) *100.
Baseline, Month 12

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Change From Baseline to Month 12 in Lean Body Mass Measured by Bioelectrical Impedance Analysis (BIA)-Adult Cohort
Time Frame: Baseline, Month 12
Lean body mass, a measurement of body composition, was assessed by DEXA scan, and calculated as lean body mass (%) = lean body mass (kg) / (lean body mass [kg] + fat mass [kg])*100.
Baseline, Month 12
Change From Baseline to Month 12 in Lean Body Mass Measured by BIA-GH Naive Pediatric and GH Treated Pediatric Cohort
Time Frame: Baseline, Month 12
Lean body mass, a measurement of body composition, was assessed by DEXA scan, and calculated as lean body mass (%) = lean body mass (kg) / (lean body mass [kg] + fat mass [kg])*100.
Baseline, Month 12
Change From Baseline to Month 12 in Body Fat (Percentage) Measured by DEXA: Adult Cohort
Time Frame: Baseline, Month 12
Body fat was assessed by DEXA scan. and calculated as body fat (%) = body fat (kg) / [lean body mass (kg) + body fat (kg)]*100.
Baseline, Month 12
Change From Baseline to Month 12 in Body Fat (Percentage) Measured by DEXA: GH Naive Pediatric and GH Treated Pediatric Cohort
Time Frame: Baseline, Month 12
Body fat was assessed by DEXA scan. and calculated as body fat (%) = body fat (kg) / [lean body mass (kg) + body fat (kg)]*100.
Baseline, Month 12
Change From Baseline to Month 12 in Adipose Tissue Distribution Measured by Abdominal Computed Tomography (CT)
Time Frame: Baseline, Month 12
Adipose tissue distribution was measured by abdominal CT. Areas of subcutaneous adipose tissue (SAT) (centimeter square [cm^2]), visceral adipose tissue (VAT) (cm^2) were measured at the level of the umbilicus by abdominal CT.
Baseline, Month 12
Change From Baseline to Month 6 in Lean Body Mass Measured by DEXA: Adult Cohort Only
Time Frame: Baseline, Month 6
Lean body mass, a measurement of body composition, was assessed by DEXA scan, and calculated as lean body mass (%) = lean body mass (kg) / (lean body mass [kg] + fat mass [kg])*100.
Baseline, Month 6
Bone Maturation
Time Frame: 12 months
Bone maturation is the process whereby the tissue undergoes changes from the embryonic rudiment of bone to the adult form. Bone maturation was calculated as bone age divided by chronological age. Participants with bone maturation value greater than 1 is presented in this outcome measure.
12 months
Number of Participants With Treatment Emergent Adverse Events and Serious Adverse Events
Time Frame: From day 1 up to 28 days after end of study treatment (maximum duration up to 38 months)
An adverse event was any untoward medical occurrence in administered medicinal product, event need not necessarily have a causal relationship with product treatment or usage. A serious adverse event was any untoward medical occurrence in a participant administered a medicinal or nutritional product (including pediatric formulas) at any dose that: resulted in death; was life-threatening; required inpatient hospitalization or prolongation of hospitalization; resulted in persistent or significant disability/incapacity (substantial disruption of the ability to conduct normal life functions); resulted in congenital anomaly/birth defect. Treatment emergent AEs were events emerged during treatment period and were absent before treatment or that worsened relative to pretreatment state. TEAEs consist of SAEs and non-SAEs
From day 1 up to 28 days after end of study treatment (maximum duration up to 38 months)
Number of Participants With Laboratory Test Abnormalities
Time Frame: From Day 1 up to 28 days after end of study treatment (maximum duration up to 38 months)
Criteria for abnormal laboratory values for chemistry parameters: alanine aminotransferase, alkaline phosphatase greater than (>) 3.0*upper limit of normal (ULN), albumin > 1.2*ULN, urea nitrogen millimoles per liter (mmol/L) > 1.3*ULN, HDL cholesterol mmol/L less than (<) 0.8* lower limit of normal (LLN), LDL cholesterol mmol/L >1.2*ULN, triglycerides mmol/L > 1.3*ULN, thyrotropin milliunits per liter (mU/L) <0.8*LLN and >1.2*ULN, glucose (mmol/L) >1.5*ULN, hemoglobin A1C liter of cells per liter of blood (L/L) >1.3*ULN.
From Day 1 up to 28 days after end of study treatment (maximum duration up to 38 months)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Pfizer

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Study Director: Pfizer CT.gov Call Center, Pfizer

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
February 9, 2021

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
December 6, 2022

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
April 15, 2024

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
January 4, 2021

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
January 4, 2021

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
January 6, 2021

Study Record Updates

Last Update Posted (Estimated)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
January 14, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
December 23, 2025

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
December 1, 2025

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • A6281323
  • 2024-000101-32 (Registry Identifier: EudraCT)
  • NCT04697381 (Registry Identifier: ClinicalTrials.gov)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

Pfizer will provide access to individual de-identified participant data and related study documents (e.g. protocol, Statistical Analysis Plan (SAP), Clinical Study Report (CSR)) upon request from qualified researchers, and subject to certain criteria, conditions, and exceptions. Further details on Pfizer's data sharing criteria and process for requesting access can be found at: https://www.pfizer.com/science/clinical_trials/trial_data_and_results/data_requests.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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