Data to be collected during the Main Study include demographic, baseline disease information and medical history including all prior disease-directed therapy. In addition, vital signs, laboratory values and adverse events information will be collected and recorded. Urine samples will be obtained and measured for orotic acid and orotidine levels. Systemic levels of uridine will be evaluated from plasma samples collected at set timepoints.
Upon successful completion of the Main Study and entry into the Treatment Extension, physical exams and vital signs will be performed every six (6) months. Additionally, plasma samples to measure systemic levels of uridine and urine samples to measure levels of orotic acid and orotidine will be collected every (6) six months.