Gonadotropin releasing hormone agonists (GnRHa) are standard of care for central precocious puberty (CPP). A 6-month subcutaneous injection has recently been approved by Food and Drug Administration.Determine efficacy, pharmacokinetics and safety of 6-month 45 mg subcutaneous leuprolide acetate for CPP.Phase 3 multicenter, open-label, single-arm study.25 sites in 6 countries.64 GnRHa naive children with CPP (age: 7.5±0.1 years) received study drug: 59 completed the study.2 doses of 45 mg subcutaneous leuprolide acetate (0.375 mL) at 0 and 24 weeks, children followed for 48 weeks.Percentage of children with serum luteinizing hormone (LH) <4 IU/L 30 minutes following GnRHa stimulation at week 24.54/62 (87%) children achieved post-stimulation LH <4 IU/L at week 24. 49/56 (88%) girls and 1/2 boys maintained peak LH <4 IU/L at week 48. Mean growth velocity decreased from 8.9 cm/year at week 4 to 6.0 cm/year at week 48. Mean bone age was advanced 3.0 years beyond chronological age at screening and 2.7 years at week 48. Breast pubertal stage regressed or was stable in 97% of girls and external genitalia development regressed in both boys. Adverse events were mild and did not cause treatment discontinuation.A small volume of 45 mg subcutaneous leuprolide acetate administered at a 6-month interval effectively suppressed pubertal hormones and stopped or caused regression of pubertal progression. This long-acting GnRHa preparation of leuprolide acetate is a new effective and well-tolerated therapy for children with CPP.