Non-GH Agents and Novel Therapeutics in the Management of Short Stature

Management of Short Stature: Use of Growth Hormone in GH-Deficient and non-GH-Deficient Conditions

Growth hormone (GH) is an important driver for somatic growth and increase in height in children. The development of recombinant human GH has greatly increased its availability, and hence the potential for its use and abuse. GH therapy should only be offered to patients with established and approved indications. Common pediatric indications for treatment include growth hormone deficiency, Turner syndrome, Prader-Willi syndrome, small for gestational age, chronic renal insufficiency, and idiopathic short stature. Before initiating treatment, the family should be counseled about the treatment goals, costs, and possible adverse effects from the treatment. It is important for patients to have realistic expectations from the treatment. The dose of GH should be individualized for the indication and will require titration in each patient based on response to the treatment and the adverse effects. Overall, GH has a good safety record. However, GH treatment has many potential and real adverse effects that need to be considered and monitored during treatment. Recently, safety concerns regarding the long-term effect of GH therapy on cardiovascular morbidity have come under scrutiny.

Should Skeletal Maturation Be Manipulated for Extra Height Gain?

Skeletal maturation can be delayed by reducing the exposure to estrogens, either by halting pubertal development through administering a GnRH analogue (GnRHa), or by blocking the conversion of androgens to estrogens through an aromatase inhibitor (AI). These agents have been investigated in children with growth disorders (off-label), either alone or in combination with recombinant human growth hormone (rhGH). GnRHa is effective in attaining a normal adult height (AH) in the treatment of children with central precocious puberty, but its effect in short children with normal timing of puberty is equivocal. If rhGH-treated children with growth hormone deficiency or those who were born small-for-gestational age are still short at pubertal onset, co-treatment with a GnRHa for 2-3 years increases AH. A similar effect was seen by adding rhGH to GnRHa treatment of children with central precocious puberty with a poor AH prediction and by adding rhGH plus GnRHa to children with congenital adrenal hyperplasia with a poor predicted adult height on conventional treatment with gluco- and mineralocorticoids. In girls with idiopathic short stature and relatively early puberty, rhGH plus GnRHa increases AH. Administration of letrozole to boys with constitutional delay of growth puberty may increase AH, and rhGH plus anastrozole may increase AH in boys with growth hormone deficiency or idiopathic short stature, but the lack of data on attained AH and potential selective loss-of-follow-up in several studies precludes firm conclusions. GnRHas appear to have a good overall safety profile, while for aromatase inhibitors conflicting data have been reported.