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Trial Investigating the Efficacy and Safety of Weekly Lonapegsomatropin Compared to Daily Somatropin in Children and Adolescents With Short Stature or Growth Failure Due to Growth Hormone Sufficient Disorders

A Pivotal, Parallel-Arm, Phase 3, Open-Label, Active-controlled, Global, Multicenter, Randomized Basket Trial Investigating the Efficacy and Safety of Once-weekly Lonapegsomatropin Compared to Daily Somatropin in Prepubertal Children and Adolescents With Growth Failure or Short Stature Due to Growth Hormone Sufficient Disorders - Turner Syndrome, SHOX Deficiency, Small for Gestational Age, and Idiopathic Short Stature

Status
Recruiting
Phases
Phase 3
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT07221851
Enrollment
186
Registered
2025-10-28
Start date
2025-12-12
Completion date
2029-03-01
Last updated
2026-09-02

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Idiopathic Short Stature, Short Stature Homeobox Gene Mutation, Small for Gestational Age at Delivery, Turner Syndrome

Keywords

Turner Syndrome, Noonan Syndrome, Growth Hormone, Short Stature, Growth Failure, Sex Chromosome Disorders, Chromosome Disorders, Endocrine System Diseases, Pituitary Hormones, Anterior, Pituitary Hormones, Hormones, Hormone Substitutes, Human Growth Hormone, Lonapegsomatropin, Sex Chromosome Disorders of Sex Development, Impaired Growth, somatropin, Growth Hormone Sufficiency, Short Stature Homeobox Gene Mutation, Short Stature Children Born Small for Gestational Age, Idiopathic Short Stature

Brief summary

This basket trial will enroll prepubertal children and adolescents with clinically diagnosed and genetically confirmed (if applicable) TS, SHOX-D, SGA, or ISS between ages of ≥2 and \<18 years with open growth plates. The purpose of the study is to see how well treatment with once-weekly lonapegsomatropin works compared to treatment with daily somatropin. Approximately 186 participants will be distributed equally (1:1), to receive either lonapegsomatropin for 2 years or somatropin for 1 year followed by lonapegsomatropin for 1 year. This trial will be conducted in the United States, France, Germany, Italy, Romania, Spain and South Korea.

Interventions

COMBINATION_PRODUCTLonapegsomatropin [SKYTROFA®]

Subcutaneous injection once weekly

COMBINATION_PRODUCTSomatropin Pen Injector

Subcutaneous injection once daily

Sponsors

Ascendis Pharma A/S
Lead SponsorINDUSTRY

Study design

Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
NONE

Intervention model description

Phase 3, parallel-arm, open-label, active-controlled, global, multicenter, randomized basket trial investigating the efficacy and safety of lonapegsomatropin compared to somatropin in prepubertal children and adolescents with growth failure or short stature due to growth hormone (GH) sufficient disorders - TS, SHOX-D, SGA, or ISS.

Eligibility

Sex/Gender
ALL
Age
2 Years to 17 Years
Healthy volunteers
No

Inclusion criteria

1. Chronological age between ≥2 and \<18 years, at start of screening. 2. Naïve to growth hormone and growth hormone promoting therapies. 3. Prepubertal. 4. Able to stand without assistance. 5. Diagnosis of TS, SHOX-D, SGA, or ISS with impaired growth or short stature, according to the following disease-specific criteria: TS or SHOX-D (Léri-Weill dyschondrosteosis): 1. Diagnosis confirmed by a genetic test. NOTE: Historical test results are acceptable for proof of diagnosis. For karyotypes, a minimum of 20 cells must be counted. 2. Impaired growth or short stature defined as: (i.) AHV \<25th percentile over a time span of 6-16 months prior to screening utilizing a historical height properly documented in a health care setting (self-measurement record is not accepted) OR (ii.) Height \<5th percentile for sex and age according to the Centers for Disease Control Growth Charts for the United States SGA without catch-up growth: c. Birth weight and/or birth length \< -2.0 SDS for gestational age according to the 2006 World Health Organization Child Growth Standards. For infants born premature, the Fenton Preterm Infant Growth Chart (Fenton 2013) should be used. d. Impaired growth or short stature defined as: (i.) AHV \<25th percentile over a time span of 6-16 months prior to screening properly documented in a health care setting (self-measurement record is not accepted) OR (ii.) Height \< -2.0 SDS for age and sex according to the 2000 Centers for Disease Control Growth Charts for the United States for children ≥ 3 years or height \< -2.5 SDS for age and sex according to the for children ≥ 2 years and \< 3 years ISS: e. Height \< -2.25 SDS for sex and age according to the Centers for Disease Control Growth Charts for the United States with no identifiable cause for short stature. f. Documented normal GH-IGF-1 axis, defined as either: (i.)IGF-1 SDS \>0 at screening based on central laboratory OR (ii.)Historical documentation of normal peak GH upon stimulation test (as defined by local institution) g. 46,XX chromosome as determined by karyotype or microarray if female. For karyotypes, a minimum of 30 cells must be counted. 6. If on hormone replacement therapies for any hormone deficiencies other than growth hormone (e.g., adrenal, thyroid), must be on adequate and stable doses for ≥4 weeks prior to and throughout screening. 7. Written, signed informed consent provided by parent(s) or legal guardian(s) of the participant. Assent should be signed by participant as required by IRB/HREC/IEC.

Exclusion criteria

1. Advanced bone age X-ray by central reading defined as \>20% above chronological age in months (Greulich 1959). 2. Closed epiphyses as defined as bone age of ≥14.0 years in females or ≥16.0 years in males. 3. Current clinical diagnosis of diabetic retinopathy 4. Any diagnosis or presence at screening of the following: 1. Untreated moderate or severe sleep apnea as determined by formal (local) read of an inpatient or at-home sleep study. 2. Prader Willi syndrome with severe obesity, history of severe upper airway obstruction, or severe respiratory impairment. 5. Signs/symptoms of intracranial hypertension, active proliferative retinopathy. 6. Uncontrolled hypo- or hyperthyroidism. 7. Uncontrolled diabetes mellitus (defined as: HbA1c \>7.5% from central laboratory at screening). 8. Known history or diagnosis of any gastrointestinal inflammatory condition, HIV, radiation exposure, other skeletal dysplasias, growth hormone deficiency, and/or cardio-thoracic surgery due to their independent effects on growth. 9. Any significant hepatic or renal abnormality, such as abnormal renal function (defined as eGFR \<60 mL/min/1.73m2). 10. Undiagnosed or uncontrolled hypertension. 11. Receiving treatment with any agent that might influence growth or interfere with GH secretion or action including any sex steroids and stimulants for attention-deficit/hyperactivity disorder (ADHD). 12. High dose inhaled glucocorticoid for more than 28 consecutive days total over the course of 12 months. 13. Female who is pregnant, plans to be pregnant, or breastfeeding. 14. Participation in another interventional clinical trial involving an investigational compound within 90 days prior to screening or in parallel to this trial. 15. Any disease or condition that, in the judgement of the investigator, may make the participant unlikely to comply with the requirements of the protocol or any condition that presents undue risk from the investigational product or trial procedures. 16.

Design outcomes

Primary

MeasureTime frameDescription
Annualized Height Velocity (AHV) (cm/year)52 WeeksTo evaluate the efficacy of lonapegsomatropin as compared to somatropin in children and adolescents with TS, SHOX-D, SGA, or ISS

Secondary

MeasureTime frameDescription
Annualized Height Velocity (AHV) (cm/year)104 WeeksTo evaluate lonapegsomatropin as compared to somatropin on additional measures of efficacy in children and adolescents with TS, SHOX-D, SGA, or ISS
Change from baseline in height standard deviation score (SDS)52 Weeks and 104 WeeksTo evaluate lonapegsomatropin as compared to somatropin on additional measures of efficacy in children and adolescents with TS, SHOX-D, SGA, or ISS
Change from baseline in Bone Age (years)52 Weeks and 104 WeeksTo evaluate the safety and tolerability of lonapegsomatropin in children and adolescents with TS, SHOX-D, SGA, or ISS via Central Reader
Change from baseline in ratio of Bone Age/chronological age52 Weeks and 104 WeeksTo evaluate the safety and tolerability of lonapegsomatropin in children and adolescents with TS, SHOX-D, SGA, or ISS via Central Reader
Number of participants with treatment-related adverse events (AEs)52 Weeks and 104 WeeksTo evaluate the safety and tolerability of lonapegsomatropin in children and adolescents with TS, SHOX-D, SGA, or ISS

Countries

France, Germany, Italy, Romania, South Korea, Spain, United States

Contacts

CONTACTAscendis Registry Inquiries
asnd_registryinquiries@ascendispharma.com+4561161658
STUDY_DIRECTORMedical Director, MD

Ascendis Pharma A/S

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Sep 3, 2026