A Study Extension Period of PEG-somatropin (Pegylated-somatropin) in the Treatment of Children With Idiopathic Short Stature

Study Overview
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Brief Summary
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After the first stage (52 weeks) of Phase II clinical trial, Pegylated recombinant human growth hormone (PEG-rhGH) injection of appropriate dose in compliance with ISS clinical treatment strategy is used to treat children with ISS (Idiopathic Short Stature). The long-term efficacy and safety of the investigational product are evaluated, which can provide more scientific and reliable medication guidance information for clinical diagnosis and treatment.

Official Title
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A Phase 2 Study Extension Period of Pegylated Somatropin (PEG-somatropin) in the Treatment of Children With Idiopathic Short Stature: An Open, Non-controlled Observational Study.

Conditions
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Dwarfism

Intervention / Treatment
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* Drug: PEG-somatropin


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: All subjects who have completed the first stage (52 weeks) of Phase II clinical trial (including negative controls) with completed follow-up records may be enrolled in the extension period study. Before the extension period study, the investigator shall fully inform the subjects and their guardians of all the information about the extension period study, including detailed follow-up procedure, treatment plan, laboratory examination items during follow-ups and possible benefits and risks. The extension period study shall only be initiated after the subjects and their guardians are well informed, and agree to cooperate and complete the treatment, follow-ups and examinations during the study, and sign the written informed consent. Exclusion Criteria: Subjects who have taken the following medications within 2 months before entering the extension period study: Aromatase inhibitors (which include but are not limited to Lelrozol and Anastrozole), with continuous medication ≥1 month; Gonadotropin releasing hormone analogues (which include but are not limited to Triptorelin, Leuprorelin and Goserelin),, with continuous medication ≥1 month; Sex steroids (which include but are not limited to any type of estrogen, progestin and androgen) , with continuous medication ≥1 month; Protein anabolic drugs (which include but are not limited to Oxandrolone, Danazol and Strombafort), with continuous medication ≥1 month; Glucocorticoids via oral/intravenous administration for more than 1 month..

Ages Eligible for Study
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Minimum Age: 4 Years
Maximum Age: 9 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: PEG-somatropin<br>After the first stage (52 weeks) of Phase II clinical trial, the initial medication dose of this extension period is 0.2 mg/kg weight/week of PEG-rhGH for the high dose group, low dose group and negative control group, and it is adjusted in accordance with yearly height velocity (HV) and IGF-1 SDS of each visit. The maximum dose shall not exceed 0.4 mg/kg weight/week. | Drug: PEG-somatropin<br>* After the first stage (52 weeks) of Phase II clinical trial, the initial medication dose of this extension period is 0.2 mg/kg weight/week of PEG-rhGH for high dose group, low dose group and negative control group, and it is adjusted in accordance with yearly height velocity (HV) and IGF-1 SDS of each visit. The maximum dose shall not exceed 0.4 mg/kg weight/week.<br>* Other names: Polyethylene Glycol Recombinant Human Somatropin Injection;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change of yearly height velocity (ΔHV) | Change of yearly height velocity before and after treatment. Yearly Height Velocity=12×(Height Yx - Height at Baseline)/(Date of Yx - Date of Baseline)(Yx refers to the height value at particular timepoint x) | Baseline，the end of 3-year addendum | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Standard deviation score of height at the actual age (ΔHT SDS) | Standard deviation score of height at the actual age. | Baseline，every 3 months，the end of 3-year addendum | 
| Change fo Bone maturation | Change fo Bone maturation before and after treatement (bone age/chronological age) | Baseline，every 3 months，the end of 3-year addendum | 
| Change of IGF-1 SDS (ΔIGF-1 SDS) | Change of IGF-1 SDS before and after treatement | Baseline，every 3 months，the end of 3-year addendum | 
| Changes of standard deviation scores of body mass index (ΔBMI SDS) | Changes of standard deviation scores of body mass index | Baseline，every 3 months，the end of 3-year addendum | 
| The yearly average dose of PEG-rhGH injection |  | Baseline，every 3 months，the end of 3-year addendum | 
| Final height (FH) | Final height | Baseline，every 3 months，the end of 3-year addendum | 
| The improvement of FH compared with the baseline predicted adult height (PAH) |  | Baseline，every 3 months，the end of 3-year addendum | 
| Improvement of NAH (near adult height) | For subjects who reach NAH with treatment but fail to follow-ups before reaching FH, the improvement of NAH in comparison with the baseline PAH (predicted adult height) shall be evaluated | Baseline，every 3 months，the end of 3-year addendum | 
| the improvement of PAH | For subjects who fail to reach NAH with treatment and fail to follow-ups before reaching FH, the improvement of PAH in comparison with the baseline PAH shall be evaluated | Baseline，every 3 months，the end of 3-year addendum | 
| The changes of the scores evaluated by the Quality of Life Scale |  | Baseline，every 3 months，the end of 3-year addendum | 
| The changes of lean body mass (LBM) (optional) |  | Baseline，every 3 months，the end of 3-year addendum | 
| The changes of fat mass (torso) (FM) (optional) |  | Baseline，every 3 months，the end of 3-year addendum | 
| The changes of the percentage of body fat (optional) |  | Baseline，every 3 months，the end of 3-year addendum | 
| The changes of bone mineral density (BMD) (optional) |  | Baseline，every 3 months，the end of 3-year addendum |