Open-Label, Extension Study to 810P202

Inclusion Criteria: 1. Successful completion of the 810P202 study. 2. Continues to be medically healthy and with clinically normal laboratory profiles, vital signs, and electrocardiograms (ECGs). 3. Weight of at least 20kg. 4. Able and willing to swallow tablets whole and not chewed, cut or crushed. 5. Written informed consent/assent obtained from the subject's parent or legally-authorized representative (LAR), and written informed assent obtained from the subject if required. Exclusion Criteria: 1. Body Mass Index (BMI) in 97th percentile or above. 2. Clinically significant change in health status that, in the opinion of the Investigator, would prevent the subject from participating in this study or successfully completing this study. 3. Pregnancy or refusal to practice contraception during the study (for female subjects of childbearing potential). 4. Any reason which, in the opinion of the Investigator, would prevent the subject from participating in the study or complying with the study procedures.