Unstimulated Luteinizing Hormone for Assessment of Suppression during Treatment of Central Precocious Puberty with 6-Month Subcutaneous Leuprolide Acetate: Correlations with Clinical Response.

INTRODUCTION: Phase 3 trial of 6-month subcutaneous leuprolide acetate (SC-LA) in children with central precocious puberty (CPP) demonstrated efficacy and safety. The aims of this secondary analysis were to evaluate unstimulated luteinizing hormone (LH) as efficacy measure, assess clinical suppression metrics, and present biochemical and clinical data for subgroups not achieving hormone suppression.

METHODS: Sixty-two children with treatment-naïve CPP received 2 doses of 45 mg SC-LA at 24-week intervals. Unstimulated and GnRH-stimulated LH, E2, and T concentrations were measured. Clinical measures included bone age (BA) and predicted adult height (PAH).

RESULTS: Eighty-four percentage and 86% of children achieved unstimulated LH <1 IU/L at weeks 24 and 48, respectively. Of 8 children not achieving unstimulated LH <1 IU/L at week 24 that completed the study, all showed a lack of pubertal stage progression and stable/decreased BA to chronological age ratio (BA/CA). Received operating characteristic (ROC) analyses suggested unstimulated LH is a good diagnostic predictor of GnRH-stimulated LH <4 IU/L at weeks 24 and 48 (AUC = 0.88). Across all children, mean BA/CA improved from 1.4 (screening) to 1.3 (week 48) and mean PAH increased by 3 cm. Of 7 girls not achieving stimulated LH <4 IU/L at week 24, all achieved E2 <10 pg/mL, showed a lack of pubertal stage progression, and had stable or decreased BA/CA by week 48. Additionally, 6/7 had increased PAH by week 48 and 4 had unstimulated LH <1 IU/L.

CONCLUSION: Unstimulated LH has value as an efficacy measure and concentrations <1 IU/L may be an adequate surrogate of treatment response in children with CPP. All children who completed the study had evidence of pubertal suppression.