Letrozole Treatment of Precocious Puberty in Girls with the McCune-Albright Syndrome: A Pilot Study

Context: Girls with McCune-Albright syndrome (MAS) and related disorders have gonadotropin-independent precocious puberty due to estrogen secretion from ovarian cysts. Their puberty does not respond to GnRH agonist therapy, and short-acting aromatase inhibitors have had limited effectiveness. Objective: Our objective was to assess the effectiveness of the potent, third-generation aromatase inhibitor letrozole in decreasing pubertal progression in girls with MAS and to assess the response of indices of bone turnover associated with the patients’ polyostotic fibrous dysplasia. Design: Subjects were evaluated at baseline and every 6 months for 12–36 months while on treatment with letrozole 1.5–2.0 mg/m2·d. Setting: This was an open-label therapeutic trial at a single clinical center. Patients: Patients included nine girls aged 3–8 yr with MAS and/or gonadotropin-independent puberty. Main Outcome Measures: Measures included rates of linear growth, bone age advance, mean ovarian volume, estradiol, episodes of ...