Patients will return to the study site at Weeks 4, 8, 12, and 16 for efficacy and safety assessments. After the Week 16 assessments have been performed, patients will receive active treatment in an open-label manner starting the next day through the end of the study (EOS) at Week 32. That is, patients who were receiving active treatment will continue to receive active treatment, and patients who were receiving placebo will switch to active treatment for the remaining 16 weeks of the study. Patients will receive only one dose of study treatment on the Week 16 visit day. Patients will return to the study site at Week 24 and Week 32 (EOS) for efficacy and safety assessments. An Early Termination visit will occur if the patient is discontinued from the study prematurely. Patients will have a follow-up visit approximately 14 days after the Early Termination visit or the Week 32 (EOS) visit.