Weekly Somatrogon versus Daily Somatropin in Children with Small for Gestational Age or Idiopathic Short Stature

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What is this study about?

The study focuses on children who were born small for gestational age or who have idiopathic short stature, meaning they are shorter than expected and no clear medical reason has been found. The medication being tested is a weekly injection called Somatrogon, which is compared with the usual daily injection of the growth hormone Genotropin.

The purpose is to determine whether the weekly treatment works at least as well as the daily treatment in promoting growth.

Participants will be assigned to receive either the weekly Somatrogon or the daily Genotropin for about twelve months. Their height will be measured regularly, and the main outcome will be the change in growth speed over the year, referred to as annualized height velocity. No additional procedures beyond the injections and height checks are required.

1 enrollment and consent

after joining the study you sign a consent form that explains the purpose, procedures, possible risks and benefits of the trial.

2 baseline assessments

the study team records your medical history, measures your height and weight, and collects blood samples to establish a starting point for later comparisons.

3 randomization to treatment group

you are assigned by a computer system to receive either the weekly somatrogon injection or the daily genotropin injection. the assignment is made without influence from the study staff.

4 injection training

a study nurse shows you how to prepare and give the injection using the provided pen or syringe, and how to store the medication safely.

5 start of medication

if you are in the somatrogon group, you receive a 60 mg solution in a pre‑filled pen and inject it under the skin once each week for a total of 12 months.

if you are in the genotropin group, you reconstitute a 12 mg powder with the supplied solvent and inject the solution under the skin once each day for a total of 12 months.

6 regular follow‑up visits

you attend clinic visits approximately at month 1, month 3, month 6, month 9 and month 12. during each visit the staff checks your overall health, records any side effects, and measures your height.

the study team may also repeat blood tests to monitor safety.

7 growth monitoring

height measurements from each visit are used to calculate the annualized hv, which is the average increase in height per year. the primary goal of the trial is to compare this value after 12 months between the two treatment groups.

8 end of treatment and final evaluation

after completing 12 months of injections you have a final study visit. the final visit includes a comprehensive health assessment, final height measurement, and collection of any remaining study data.

9 study completion

all data are entered into the study database, and the trial is closed for each participant. no further study‑specific procedures are required.

Who Can Join the Study?

The child must have been diagnosed with Small for Gestational Age (SGA), which means they were born weighing and/or measuring at least 2 standard deviations (SD) below the average size for the week of pregnancy, according to national growth charts.
The child must have been diagnosed with Idiopathic Short Stature (ISS), which means their height is at least 2 SD below the average for their age and gender, and they do not have growth hormone deficiency (their highest growth‑hormone test result was greater than 10 ng/mL within the past 24 months).
If the child has SGA and is a girl, she must be pre‑pubertal (in Tanner stage 1 for breast development), be at least 4 years old in the EU (or at least 3 years old outside the EU), be younger than 9 years (up to 8 years 364 days) on the day the study paperwork is signed, and have a bone age that is not older than her actual age, measured within the last 8 weeks.
If the child has SGA and is a boy, he must be pre‑pubertal (in Tanner stage 1 for testicular development), be at least 4 years old in the EU (or at least 3 years old outside the EU), be younger than 11 years (up to 10 years 364 days) on the day the study paperwork is signed, and have a bone age that is not older than his actual age, measured within the last 8 weeks.
If the child has ISS and is a girl, she must be pre‑pubertal (in Tanner stage 1 for breast development), be at least 4 years old in the EU (or at least 3 years old outside the EU), be younger than 9 years (up to 8 years 364 days) on the day the study paperwork is signed, and have a bone age that is not older than her actual age and not more than 2 years younger than her actual age, measured within the last 8 weeks.
If the child has ISS and is a boy, he must be pre‑pubertal (in Tanner stage 1 for testicular development), be at least 4 years old in the EU (or at least 3 years old outside the EU), be younger than 11 years (up to 10 years 364 days) on the day the study paperwork is signed, and have a bone age that is not older than his actual age and not more than 2 years younger than his actual age, measured within the last 8 weeks.
The child (and their parent or legal guardian) must be able to give a signed informed consent (or assent from the child) and agree to follow all study requirements and restrictions.

Who Cannot Join the Study?

You have a history of cancer or have received treatments such as radiation therapy or chemotherapy.
Your short height is caused mainly by emotional or social factors, known as psychosocial short stature.
You have or may have a chromosome problem (called a chromosomal abnormality) such as Turner syndrome, Laron syndrome, Noonan syndrome, Prader‑Willi syndrome, Russell‑Silver syndrome, or SHOX gene changes.
The growth plates at the ends of your bones (called epiphyses) are already closed.

intracranial tumour

intracranial cyst

You are currently very ill with serious complications after major surgery (like heart or abdominal surgery), severe injury, or acute breathing failure.
You have high pressure inside the skull (benign intracranial hypertension) that is causing swelling of the optic nerve head (papilledema).

untreated hormonal deficiency

You have conditions such as type 2 diabetes, cancer, long‑lasting infections, or other known reasons that can cause poor growth.
Your blood level of a growth‑related protein called IGF‑1 is more than two standard scores above normal (written as IGF‑1 > 2 SDS).

growth hormone deficiency (GHD)

microcephaly

skeletal dysplasia

Where you can join this trial?

Verified and Recommended Sites

No sites found in this category

Verified Sites

Site Name	City	Country
Uniwersytecki Szpital Kliniczny Im Jana Mikulicza Radeckiego We Wroclawiu	Wroclaw	Poland
Pomeranian Medical University	Szczecin	Poland
Kliniczny Szpital Wojewodzki Nr 2 Im. Sw. Jadwigi Krolowej W Rzeszowie	Rzeszow	Poland
Hopital Necker Enfants Malades	Paris	France

Other Sites

Site Name	City	Country
Athens General Children’s Hospital Panagioti And Aglaia Kyriakou	Athens	Greece
University General Hospital Of Thessaloniki Ahepa	Thessaloniki	Greece
University Hospital Ostrava	Ostrava	Czechia
Fakultni Nemocnice Brno	Brno	Czechia
Ippokratio General Hospital Of Thessaloniki	Thessaloniki	Greece
University General Hospital Attikon General Hospital Of West Attica H Agia Varvara	Chaidari	Greece
Instytut Centrum Zdrowia Matki Polki	Lodz	Poland
Uniwersytecki Szpital Dzieciecy W Krakowie	Cracow	Poland
Centre Hospitalier Lyon Sud	Pierre Benite	France
Hopital Beaujon	Clichy	France
Fhscnctl nhytanatv Mmgud a Hbhgjxd	Prague	Czechia
Akrpdvzskb Pawyjesj Hghppbat Db Mhapxyksr	Marseille	France
Crxnmo Hufepacotqm Rbmroahx Dkidtzrgenbovz	Angers	France

Trial status

Country	Status	Recruitment Start
Czechia	Not yet recruiting	01.04.2026
France	Not yet recruiting	01.04.2026
Greece	Not yet recruiting	01.04.2026
Poland	Not yet recruiting	01.04.2026

Trial locations

Investigated drugs:

Somatropin

Genotropin is a daily injectable growth hormone used to help children who are born small for their gestational age or have idiopathic short stature grow taller. In this study, it serves as the standard treatment (comparator) against which the new weekly medication is measured. Participants receive a dose each day, and the researchers track how well it supports growth compared with the weekly option.

Somatrogon is a newer growth hormone designed to be given once a week instead of every day. In the trial, it is the test medication being evaluated to see if it works at least as well as the daily Genotropin. Children receive the weekly injection, and the study examines whether this less‑frequent dosing can provide similar growth benefits while possibly being more convenient.

Investigated diseases:

Short stature

Small for gestational age – A baby who is smaller than the usual weight for the number of weeks of pregnancy. The condition is identified at birth when the infant’s weight falls below the 10th percentile for gestational age. Growth may continue at a slower rate compared with peers during early childhood. Some children gradually catch up in size, while others remain smaller over time. The pattern of growth often reflects the underlying cause of the reduced size in utero.

Idiopathic short stature – A condition where a child’s height is significantly below the average for their age and sex, and no specific medical reason can be identified. Growth typically follows a steady but reduced trajectory compared with normal growth curves. The short stature persists throughout childhood and adolescence unless an underlying cause is later discovered. Height measurements remain consistently lower than expected for the child’s genetic potential. The condition is recognized by its persistent pattern of limited growth.

Trial ID:

2025-523832-38-00

Protocol code:

RCRC000035

NCT ID:

NCT07226089

Trial Phase:

Therapeutic confirmatory (Phase III)

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Weekly Somatrogon versus Daily Somatropin in Children with Small for Gestational Age or Idiopathic Short Stature

What is this study about?

Who Can Join the Study?

Who Cannot Join the Study?