Aromatase inhibitor, GH combination increases growth in boys with idiopathic short stature

BOSTON — In adolescent boys with idiopathic short stature, combination therapy with growth hormone and aromatase inhibitors was more effective in increasing adult height potential than growth hormone or aromatase inhibitors alone through 24 months.

A strong safety profile was found with the combination of GH and aromatase inhibitors, according to the researchers.

Nelly Mauras

Nelly Mauras, MD, chief of the division of endocrinology, diabetes and metabolism at Nemours Children’s Health System in Jacksonville, Florida, and colleagues evaluated 76 pubertal adolescent boys (mean age, 14.1 years) with significant short stature and no identifiable hormonal or other pathology to determine the efficacy and safety of aromatase inhibitors compared with GH alone and in combination for increasing adult height. Participants were randomly assigned to aromatase inhibitors alone (n = 25; Arimidex [anastrozole, AstraZeneca] or Femara [letrozole, Novartis]), GH alone (n = 25) or a combination (n = 26) for 24 months. A protocol extension through 36 months was offered to participants with residual adult height potential who wished to continue on treatment.

Overall, 72 participants completed 12 months, 65 completed 24 months, and 21 continued through 36 months; the remaining participants are still being followed to near-adult height.

At 24 months, adult height was increased more in the combination group (+18.8 cm) compared with the GH alone group (+17 cm) and aromatase inhibitor alone group (14.2 cm; P = .0002.).

The combination group had a greater change in predicted adult height at 24 months (+7.6 cm) compared with the GH alone group (+4.2 cm) and aromatase inhibitor alone group (+1.3 cm; P < .0001). The combination group had more growth in fat-free mass compared with the other two groups (P = .033).

Compared with participants who did not continue treatment through 36 months (n = 31), linear growth was greater in those who remained in the study for all three groups (combination group, P = .0001), GH alone (P < .0001) and aromatase inhibitor alone (P = .33).

“Treating the growth-retarded child in puberty presents significant challenges not easily overcome by the use of GH alone, as the presence of sex steroids significantly limits the time available for linear growth in that period,” Mauras said in a press release. “This work provides the longest treatment and follow-up reported using aromatase inhibitors in adolescent males, showing an excellent safety profile. [Aromatase inhibitors] may prolong the growth life of these children, allowing for taller height, without slowing down their progression through puberty.” – by Amber Cox

Reference:

Mauras N, et al. OR31-4. Presented at: The Endocrine Society Annual Meeting; April 1-4, 2016; Boston.

Disclosure: Mauras reports being a principal investigator for Astra Zeneca.