Visit 3: After two weeks at a dose of 4 grams/m2/day, the subject will fast after 8 PM, and will come to the PCTRC the following morning to have an IV placed and blood draws. If the subject's blood work from the previous visit shows that there is no concern, the subject's dose will be increased to 6 grams/m2/day. The subject will receive the first dose at this level in the PCTRC with breakfast, and blood samples will be collected from the IV every 2 hours for the next 8 hours. The subject will continue on this dose for two weeks.