Tamoxifen treatment for precocious puberty in McCune-Albright syndrome: a multicenter trial.

Abstract Objective We undertook a 1-year multicenter trial of tamoxifen treatment for precocious puberty in girls with McCune-Albright syndrome (MAS). Study design Girls ≤10 years with classic or atypical MAS were recruited. Pretreatment history was collected for 6 months. Patients received 20 mg tamoxifen daily. Diaries were used to record bleeding. Evaluations included physical examination, bone age, pelvic ultrasound, hormone levels, and safety assessments. Results A total of 28 girls (2.9-10.9 years of age) were enrolled from 20 centers, of whom 25 completed 12 months of tamoxifen treatment. Compared with before the study, vaginal bleeding episodes decreased (3.42±3.36/year vs 1.17±1.41/year), growth velocity slowed (SDS 1.22±2.65 vs −0.59±3.06, P  = .005), and rate of bone maturation decreased (1.21±0.78 vs 0.72±0.36, P  = .02). Ovarian volumes were enlarged and asymmetric throughout the study, and uterine volumes were increased. No adverse events occurred. Conclusions Tamoxifen treatment of precocious puberty in MAS results in a reduction of vaginal bleeding and significant improvements in growth velocity and rate of skeletal maturation.