The purpose of this study is to assess dosing requirements and establish the efficacy of SR-hGH in idiopathic short stature patients (ISS). This phase II study is designed as multi-center, randomized, active comparator-controlled, parallel, open-label.

45 patients were randomized to three arms with 1:1:1 ratio, two arms of Sr-hGH and one of daily hGH. Two doses of Sr-hGH were administered, which are 0.5 and 0.7mg/kg/week. And the other arm received daily hGH at 0.37 mg/kg/week.

Patients in Sr-hGH groups injected on a specific day of the every week for 26 weeks. And patients randomized to daily hGH group injected for 6 days a week.

Patients visited study centers five times, firstly at screening (Visit 1), at randomization (Visit 2), after 13th dosing (Visit 3), after 26th dosing (Visit 4), and finally for follow-up (Visit5).

Criteria

• are older than or equal to age of 4
• are pre-pubertal (Tanner's stage I)
• are younger than bone age of 9 in female; of 11 in male
• have less than 3 years of a difference in bone and chronological age
• have confirmed idiopathic short stature