Aromatase inhibitors
Inhibit the action of the aromatase enzyme, which has a role in oestrogen synthesis.[61]Hero M, Varimo T, Raivio T. Aromatase inhibitors in puberty. Curr Opin Endocr Metab Res. 2020 Oct;14:37-41.
https://www.sciencedirect.com/science/article/pii/S2451965020300351
Aromatase inhibitors are approved in some countries for the treatment of breast cancer and gynecomastia.[61]Hero M, Varimo T, Raivio T. Aromatase inhibitors in puberty. Curr Opin Endocr Metab Res. 2020 Oct;14:37-41.
https://www.sciencedirect.com/science/article/pii/S2451965020300351
Anastrozole and letrozole are third-generation aromatase inhibitors under investigation for delayed puberty and short stature.[61]Hero M, Varimo T, Raivio T. Aromatase inhibitors in puberty. Curr Opin Endocr Metab Res. 2020 Oct;14:37-41.
https://www.sciencedirect.com/science/article/pii/S2451965020300351
One small phase 3 study in boys ages ≥14 years with constitutional delay showed that testicular growth and levels of pituitary hormones were greater with letrozole than testosterone, with similar adverse events between treatment groups.[62]Varimo T, Huopio H, Kariola L, et al. Letrozole versus testosterone for promotion of endogenous puberty in boys with constitutional delay of growth and puberty: a randomised controlled phase 3 trial. Lancet Child Adolesc Health. 2019 Feb;3(2):109-120.
http://www.ncbi.nlm.nih.gov/pubmed/30612946?tool=bestpractice.com
Studies of anastrozole in males with short stature have shown that it increases height potential with an acceptable safety profile.[63]Mauras N, Gonzalez de Pijem L, Hsiang HY, et al. Anastrozole increases predicted adult height of short adolescent males treated with growth hormone: a randomized, placebo-controlled, multicenter trial for one to three years. J Clin Endocrinol Metab. 2008 Mar;93(3):823-31.
https://academic.oup.com/jcem/article/93/3/823/2598440?login=false
http://www.ncbi.nlm.nih.gov/pubmed/18165285?tool=bestpractice.com
[64]Mauras N, Ross JL, Gagliardi P, et al. Randomized trial of aromatase inhibitors, growth hormone, or combination in pubertal boys with idiopathic, short stature. J Clin Endocrinol Metab. 2016 Dec;101(12):4984-93.
https://academic.oup.com/jcem/article/101/12/4984/2765085?login=false
http://www.ncbi.nlm.nih.gov/pubmed/27710241?tool=bestpractice.com
Investigation of the efficacy and safety of both treatments remains ongoing.