Resumption of Growth after Methionyl-Free Human Growth Hormone Therapy in a Patient with Neutralizing Antibodies to Methionyl Human Growth Hormone

A 16-5/12 year-old male was diagnosed with classical growth hormone (GH) deficiency at the age of 8-6/12 years and was treated with recombinant methionyl human growth hormone (m-hGH). Height increased from 104.0 cm to 107.4 cm over the first 6 months. After that, for 1 year, he demonstrated poor growth velocity which was found to be secondary to a high titer of GH antibodies with GH binding capacity >2 mg/l. After a 7-month washout period during which no GH was given, at age 11 years he was placed on recombinant methionyl-free human growth hormone (met-free hGH). His height increased 14.9 cm in 11 months (annualized growth rate of 16.2 cm/year). This report illustrates that evaluation of growth failure during GH therapy should include measurement of anti-GH antibodies so that an appropriate alteration of GH therapy can be made if indicated.