A Study to Optimize Growth Hormone Dosing in Children With Chronic Kidney Disease by Measuring IGF-1 Levels in Blood

The study will involve 30 children with chronic kidney disease and failure to grow. The study will last for 14 months. There will be a screening clinic visit if the child qualifies for the study, Week -8. Each clinic visit will include, getting a medical history, a physical exam, and a blood test. Also an x-ray of the wrist to calculate bone age. If abnormal blood values are found as a result of kidney failure then an attempt will be made to correct them over the next 2 months before enrollment in the study. Also children will be asked to keep track of all of the foods for 3 days every month during the study. A study nutritionist will call them once each month to go over the food diary. At study Week -4, children will come again for a clinic visit. Then at Week 0 of the study, a decision will be made randomly based on the level of kidney function to what dose of growth hormone a child will receive. This will be either a low dose of growth hormone or a high dose of growth hormone. At the Week 1 and Week 4 visits, children will come for a clinic visit. Children will take growth hormone (through a needle under the skin) every night for a full 7 days during each of the two weeks. In the mornings before the 1st and after the 7th dose both weeks, children will have their blood drawn to check IGF-1 levels. During Weeks 2 and 3, children will not take any growth hormone in order to allow the body to clear, or "wash-out", the medication from the system before Week 4. At Week 5, children will begin taking growth hormone each evening and continue to do so every day through Week 28. Then, for Weeks 29 and 30, children will have another "wash-out" period with no growth hormone treatment. At Week 31, blood will be drawn in the mornings before the 1st and after the 7th dose of growth hormone treatment. From Week 32 on, children will take growth hormone every evening and continue to do so through Week 56, the end of the study. Also at week 1, skin fold measurements to assess body fat will be done on all subjects. A DEXA scan, a test that measures body fat and muscle mass will be done on the older children in the study on an optional basis on Weeks 1, 28 and 56. Another wrist X-ray for bone age will be repeated at 56 weeks of the study.