 This trial will be performed in 2 segments. In Segment 1, subjects will be randomized to receive either CF101 1.0 mg, or matching placebo, given orally every 12 hours for 16 weeks. Segment 1 will enroll approximately 44 subjects, randomized in a 3:1 ratio to CF101 1.0 mg or to placebo. At the conclusion of Segment 1, a Data Review Committee DRC will review safety and efficacy data and advise on progression of the trial to Segment 2. Segment 2 will enroll up to approximately 44 subjects randomized in a 3:1 ratio to CF101 2.0 mg 3:1 ratio to receive with CF101 2.0 mg, or matching placebo, given orally every 12 hours for 16 weeks. 