ESPE Abstracts

Objectives: Estrogen is a key hormone to promote epiphyseal closure. So the inhibition of estrogen production can prolong the growth time of adolescent children. Therefore, aromatase inhibitors can be applied to adolescent children who has older bone age. In addition to reduction of the estrogen levels, it can promote linear growth. This study analyzed the safety and efficacy of letrozole in children for clinical reference.

Methods: We collect the data of changes of indicators and adverse events during the treatment of letrozole in adolescent boys with older bone age and short stature in Beijing Children 's Hospital from August 2017 to February 2023. And they return visit in the outpatient every three months to monitor relative indexs and adverse events.

Results: A total of 65 children were enrolled, with an average age of (13.53±1.02) years, an average bone age of (14.46±0.83) years, and an average course of treatment of (11.74±6.19) months. The group got final adult height whose mean value was (170.59±4.58), and the target height was (168.96±4.90) cm. There was no significant difference between the two groups(P =0.22). Compared with the baseline height data of children before treatment, the average value of final adult height was (170.59±4.58) cm, the height SDS was (-0.15±0.81), the average value of baseline height was (156.91±7.01) cm, and the height SDS was (-0.55±1.35). The difference was statistically significant(P <0.05). Some children did not reach final adult height. Compared with the baseline height data before treatment, the average height of the last follow-up was (168.22±5.29) cm, and the average height SDS was (-0.42±1.20). The average baseline height before treatment was (157.32±6.66) cm, and the baseline height SDS was (-0.09±0.93). The difference was also statistically significant (P <0.01). The main adverse reactions during the follow-up were acne, lower limb pain, alopecia, lethargy, irritability, excitement. Regular monitoring of laboratory indicators, the increasing of uric acid, insulin, creatine kinase is the most common. All of the children had no serious adverse reactions.

Conclusion: Letrozole combined with recombinant human growth hormone is effective and feasible in the treatment of adolescent male children with older bone age and short stature. And the safety is satisfactory. because it certainly belongs to off-labeled indications, regular follow-up is necessary.