Mecasermin rinfabate.

Mecasermin rinfabate, a complex of equimolar amounts of insulin-like growth factor (IGF)-I and its binding protein IGFBP-3, has been approved by the U.S. Food and Drug Administration for treatment of severe primary IGF deficiency or for patients with growth hormone gene deletion who have developed neutralizing antibodies to growth hormone. It has been shown to increase growth velocity in children with either condition. In the past there have been adverse events, particularly hypoglycemia, reported with administration of unbound recombinant human IGF-I (rhIGF-I). In addition, the serum half-life of unbound rhIGF-I is shorter when administered to patients with growth hormone insensitivity syndrome, who have low serum concentrations of its binding proteins IGFBP-3 and acid-labile subunit, than when administered to healthy volunteers or to patients with an IGF-I gene deletion who have normal levels of IGFBP-3. Mecasermin rinfabate prolongs the half-life of rhIGF and should counteract acute adverse events, particularly hypoglycemia, associated with the administration of IGF-I.