Growth Hormone Excess

Background:
For children with gigantism, too much growth hormone (GH) in the body causes abnormal growth and many other problems. Current treatments often don t work; no medical treatment is approved by FDA. Researchers want to see if the drug pegvisomant can help.
Objective:
To test the role of pegvisomant in children and adolescents with gigantism.
Eligibility:
People ages 2-18 with GH excess for whom usual treatments have not worked or who are not eliginle for them
Design:
Participants will be screened with a medical history.
The study will last 60 weeks and include at least 3 visits: baseline, 6-month, and 12-month visits. For the baseline visit, participants will stay a few nights for testing. They may stay overnight for the other visits.
All visits will include:
Medical history
Physical exam
Questionnaires
Heart and liver tests
Participants may be photographed in their underwear if they agree.
Blood tests: Participants will get a catheter: A small plastic tube will be placed in an arm vein. For some tests, the blood may be drawn every 30 minutes over 3 hours. For other tests, blood will be drawn every 20 minutes over 12 hours. Only clinically necessary tests will be done in each patient.
At the baseline visit, participants will have the study drug injected under the skin. They will learn to take the injection at home. They will take the injection daily during the study.
The baseline and 12-month visits will include:
MRI: Participants will have a dye injected into a vein. They will lie in a machine that takes pictures of the body.
Hand X-ray
Participants must get their height and weight at their local doctor s office monthly.
Participants must have blood and urine tests at their local lab monthly for the first 6 months then every 3 months until the study ends.
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