• Proportion of patients who fail to complete therapy in each of the dosing groups
  

• 1. Rate of serious adverse events in each of the dosing groups
  
• 2. Rate of total adverse events in each of the groups
  
• 3. Rate of relapse in patients with positive sputum culture at 2 months, in each of the groups
  

Prospective, randomized, double-blinded, comparative study. Patients are randomized at the completion of induction phase therapy. Sample-size is 50 HIV-seronegative patients with culture-positive, drug susceptible TB in each treatment arm. The first 75 patients will be randomized 2:1 to 900 mg:600 mg rifapentine. The second 75 patients will be randomized 2:1 to 1200 mg:600 mg rifapentine. The DSMB will review tolerability and safety data on the first 21 patients enrolled (at the 900 mg and 600 mg doses) and approve proceeding to enrollment at the 1200 mg dose.

Inclusions:

1. Drug susceptible culture-positive tuberculosis
2. Adequate induction therapy
3. Age >18
4. Normal screening labs
5. Karnofsky >=60
6. Informed consent
7. Birth control if of child bearing potential

Exclusions:

1. SilicoTB
2. Skeletal or CNS TB
3. Pregnant or breastfeeding
4. Intolerance to INH or rifamycins
5. Over 70 days TB treatment just prior to enrollment