FDA Approves Gene Hormone : Biosynthetic Product Aids Children’s Growth
WASHINGTON — The Food and Drug Administration on Friday approved the marketing of the first genetically engineered human growth hormone designed to help children with pituitary gland deficiencies achieve normal or near-normal height.
About 10,000 to 15,000 children in the United States are estimated to suffer from growth hormone deficiency, which can prevent them from growing more than four feet tall.
“Approval of this new biosynthetic product represents yet another success in this country’s newest genetic engineering technologies and fulfills a genuine need of many of our pediatric patients,” FDA Commissioner Frank E. Young said.
The FDA said that the new hormone is effective only when given to children before puberty because it cannot stimulate height after that stage. The agency also said that use of the hormone will not enable children to grow taller than their genetic potential.
The genetically engineered growth hormone was developed by Genentech Inc., a biotechnology firm in South San Francisco. Marketed under the trademark name Protropin, the hormone will be available immediately through pharmacies at hospitals where children with the disease are treated by pediatric specialists.
“This is a significant breakthrough because, for the first time, all the children who suffer from growth hormone deficiency will have sufficient product to fill the need,” Robert A. Swanson, chief executive officer of Genentech, said in an interview.
Protropin is the second genetically engineered pharmaceutical to be approved in the United States. The first was a human insulin also discovered by Genentech.
Appear Much Younger
Children with growth hormone deficiency are usually normal in size at birth but fall noticeably behind other children in their growth by the time they enter grade school. They also appear much younger than their age during childhood and adolescence.
Some medical experts believe that children should be checked for growth hormone deficiency if they grow less than two inches a year between the ages of 3 and 12 years.
Growth hormone deficiency is only one of several causes--including chromosomal or bone abnormalities--that can cause a person to be shorter than average height.
In the past, children suffering from growth hormone deficiency have been treated with a hormone derived from the human pituitary gland, situated at the base of the brain, which was removed from cadavers during autopsies.
Distribution Halted
Distribution of the hormone derived from human tissue was halted this spring after three children being treated with it died after contracting an extremely rare infection. Medical experts theorized that some of the material had contained a virus known to exist in the brain tissues of patients with the disease.
The new genetically engineered hormone is synthesized in a special laboratory strain that has been modified by the addition of the gene for human growth hormone production. As a result, the FDA said contamination with such viruses “is not believed to be possible.”
The agency said the new process will provide an adequate supply of the hormone available to treat children who have the deficiency.
