Treatment with depot leuprolide acetate in girls with idiopathic precocious puberty: What is the best parameter to decide the initial dose?
Doses of GnRH analogues used to treat idiopathic central precocious puberty(iCPP) may vary with clinician preference. Aim of this study is to evaluate the efficacy of a monthly 3.75mg dose of leuprolide acetate(LA) to suppress the hypothalamo-pituitary-gonadal(HPG) axis in girls with iCPP and to determine factors that may have an impact on the supressing dose.
A total of 220 girls receiving LA for iCPP were included. LA is started at a dose of 3.75mg/28 days, and suppression is examined using GnRH test at the 3rd month. Clinical signs and symptoms of puberty were also evaluated to determine whether pubertal suppression was achieved clinically. Dose of LA is increased to 7.5mg/28 days in those who have a peak LH≥2IU/L and in whom adequate suppression of pubertal signs was not achieved. ROC curves were used to determine thresholds for clinical and hormonal factors with an impact on the suppressing dose of LA.We analyzed whether thresholds differentiate two populations using LA either at a dose of 3.75mg or 7.5mg, with logistic regression analyses.
Peak stimulated LH in 88.6% of the patients was <2IU/L under treatment with 3.75 mg. Best threshold values that differentiate the two doses were 36.2kg for body weight(BW), 1.64 for BMI-SDS(p<0.001). Multiple logistic regressions showed BW, and BMI-SDS above thresholds indicated requirement of LA at a dose of 7.5mg/28 days(p<0.001).
3.75 mg monthly injections of LA is an effective treatment in majority of girls with iCPP, however higher initial dose may be preferred in patients with a BW≥36kg or BMI-SDS≥1.6 for effective suppression of HPG axis.