Treatment with the aromatase inhibitor letrozole during adolescence increases near-final height in boys with constitutional delay of puberty

• Published in: Clinical endocrinology (Oxford) Vol. 64; no. 5; pp. 510 - 513
• Main Authors: Hero, Matti, Wickman, Sanna, Dunkel, Leo
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01-05-2006; Blackwell; Wiley Subscription Services, Inc
• Subjects: Adolescent; Aromatase Inhibitors - therapeutic use; Biological and medical sciences; Body Height - drug effects; Endocrinopathies; Estradiol - blood; Follicle Stimulating Hormone - blood; Fundamental and applied biological sciences. Psychology; Humans; Luteinizing Hormone - blood; Male; Medical sciences; Nitriles - therapeutic use; Prospective Studies; Puberty, Delayed - blood; Puberty, Delayed - drug therapy; Testosterone - blood; Time Factors; Triazoles - therapeutic use; Vertebrates: endocrinology; Endocrinopathy; Human; Aromatase inhibitor; Enzyme; Antiestrogen; Enzyme inhibitor; Male; Corporal biometry; Antihormone; Estrogen synthase; Treatment; Delayed puberty; Body size; Adolescent; Triazole derivatives; Height; Non steroid compound; Child; Endocrinology; Letrozole
• ISSN: 0300-0664; 1365-2265
• DOI: 10.1111/j.1365-2265.2006.02499.x

Summary
Objective  We investigated whether inhibition of oestrogen biosynthesis with the aromatase inhibitor, letrozole, during adolescence improves near‐final height in boys with constitutional delay of puberty.
Patients and methods  Seventeen boys with constitutional delay of puberty were randomized to receive testosterone (T) enanthate (1 mg/kg i.m.) every 4 weeks for 6 months in combination with placebo (Pl, n = 8), or the aromatase inhibitor letrozole (Lz, 2·5 mg/day orally) (n = 9), for 12 months. After treatment, patients were followed up until near‐final height. Height discrepancy was calculated as near‐final height minus mid‐parental target height.
Measurements  The primary end point was the difference in near‐final height between the groups treated either with T + Pl or T + Lz. Secondarily, height discrepancy and gain in height standard deviation score (SDS) were analysed in both groups.
Results  Boys treated with T + Lz reached a higher mean near‐final height than did boys on T + Pl (175·8 vs. 169·1 cm, respectively, P = 0·04). In T + Lz‐treated boys, mean near‐final height did not differ from their mid‐parental target height (175·8 vs. 177·1 cm, P = 0·38), whereas in T + Pl‐treated boys, mean near‐final height was lower than mid‐parental target height (169·1 vs. 173·9 cm, P = 0·007). T + Lz‐treated boys had a greater increment in height SDS over the pretreatment height SDS than T + Pl‐treated boys (+1·4 SDS vs.+0·8 SDS, P = 0·03).
Conclusions  Our findings indicate that in adolescent boys an increase in adult height can be attained by use of aromatase inhibitors.