Results of a Second Year of Therapy with the 12-Month Histrelin Implant for the Treatment of Central Precocious Puberty

Abstract

<p/> <p><it>Background</it>. Gonadotropin releasing hormone analogs (GnRHas) are standard of care for central precocious puberty (CPP). The histrelin subcutaneous implant is safe and effective in the treatment of CPP for one year. <it>Objective</it>. The study evaluates a second year of therapy in children with CPP who received a new implant after one year of treatment. <it>Methods</it>. A prospective one-year study following an initial 12-month treatment period was conducted. <it>Results</it>. Thirty-one patients (29 girls) aged <inline-formula><graphic file="1687-9856-2009-812517-i1.gif"/></inline-formula> years received a second implant. Eighteen were naïve to GnRHa therapy at first implantation. Peak LH declined from <inline-formula><graphic file="1687-9856-2009-812517-i2.gif"/></inline-formula> mIU/mL at 12 months to <inline-formula><graphic file="1687-9856-2009-812517-i3.gif"/></inline-formula> mIU/mL at 24 months (<inline-formula><graphic file="1687-9856-2009-812517-i4.gif"/></inline-formula>< .0001) in naïve subjects, and from <inline-formula><graphic file="1687-9856-2009-812517-i5.gif"/></inline-formula> mIU/mL at 12 months to <inline-formula><graphic file="1687-9856-2009-812517-i6.gif"/></inline-formula> mIU/mL at 24 months (<inline-formula><graphic file="1687-9856-2009-812517-i7.gif"/></inline-formula>) in previously treated subjects. Predicted adult height increased by 5.1 cm at 24 months (<inline-formula><graphic file="1687-9856-2009-812517-i8.gif"/></inline-formula>). Minor implant site reactions occurred in 61%, while minor difficulties with explantation occurred in 32.2% of subjects. <it>Conclusion</it>. The histrelin implant demonstrates profound hypothalamic-pituitary-gonadal axis suppression when a new implant is placed for a second year of treatment. Prospective follow-up of this therapeutic modality for the treatment of CPP is needed.</p>