In clinical studies of 71 subjects with Primary IGFD treated for a mean duration of 3.9 years and representing 274 subject-years, no subjects withdrew from any clinical study because of adverse events. Hypoglycemia was reported by 30 subjects (42%) at least once during their course of therapy.

Almost half of these patients had hypoglycemia prior to IGF-1 treatment. Most cases were mild or moderate in severity. Five subjects had severe hypoglycemia (requiring assistance and treatment) on one or more occasion, and four subjects experienced hypoglycemic seizures/loss of consciousness on one or more occasion. Of the 30 subjects reporting hypoglycemia, 14 (47%) had a history of hypoglycemia prior to treatment. The frequency of hypoglycemia was highest in the first month of treatment, and episodes were more frequent in younger children.

Hypoglycemia was generally avoided when a meal or snack was consumed either shortly before or shortly after administration. Tonsillar hypertrophy was noted in 11 subjects (15%) in the first 1 to 2 years of therapy with lesser tonsillar growth in subsequent years.

Intracranial hypertension occurred in three subjects. In two subjects, the events resolved without interruption of Increlex treatment. Increlex treatment was discontinued in the third subject and resumed later at a lower dose without recurrence.