At least 255 patients will be randomized at 4 study sites in South East Asia, India and Africa. Each investigational site will enroll between 60 and 90 patients to yield approximately 65 "per protocol" patients in each treatment arm . Patients will be randomized to 1 of 3 dose groups. Patients will be administered RBx 11160 with matching placebo tablets as required to maintain the study blind.