SomatoKine: is there a use in treating growth disorders?

Growth hormone (GH) has been used to treat GH deficiency since the late 1950s, and recombinant GH has been available since 1985. GH is also approved to treat non-GH-deficient short stature, such as that seen in Turner syndrome, chronic renal insufficiency, Prader-Willi syndrome, children who are small for gestational age, and idiopathic short stature. There has been interest in using recombinant insulin-like growth factor I (IGF-I) to treat short stature, either alone or in combination with its binding protein, IGF binding protein (IGFBP)-3 (SomatoKine). IGF-I increases growth velocity in children with IGF deficiency, either as a result of growth hormone insensitivity syndrome (GHIS) or IGF-I gene deletion. However, there have been adverse events, particularly hypoglycemia, reported with administration of unbound IGF-I. In addition, the serum half-life of unbound IGF-I is shorter when administered to patients with GHIS, who have low serum concentrations of its primary binding protein IGFBP-3 than when administered to healthy individuals or to patients with an IGF-I gene deletion (who have normal levels of IGFBP-3). SomatoKine was developed to prolong the half-life and to counteract acute adverse events (particularly hypoglycemia) associated with IGF-I administration. SomatoKine appears to have a longer half-life in patients with GHIS than unbound IGF-I and fewer adverse events (including hypoglycemia) have been reported when administered to patients with diabetes.