The study design of the Extension study includes 4 clinic visits over a maximum of 24 weeks. Subject eligibility will be established at Visit 1 during the crossover day from the Parent study to the extension study (Day 0). Follow-up visits will be conducted every 6 weeks up to 24 weeks (Visit 4). At Visit 4, subjects will have a final evaluation conducted 24 weeks following study entry (48 weeks from Parent study randomization).