Tuberculosis Treatment Shortening Trial

Tuberculosis (TB) is a major global health problem. TB is the current leading cause of death due to an identifiable infectious agent worldwide. One of the highest priorities for tuberculosis control programs is to shorten anti-TB treatment while maintaining its effectiveness. Current 6-month short course chemotherapy regimens are over 95% effective for the treatment of tuberculosis when fully administered. Six months is a long time, however, and patients frequently discontinue anti-TB treatment once their symptoms have improved. The duration of standard short course chemotherapy is one of the major obstacles to its successful application and poses substantial challenges to programs with respect to patient adherence, program resource needs, and logistical requirements for directly observed therapy. The primary objective of this study is to assess the efficacy of shortening anti-TB treatment to 4 months in human immunodeficiency virus (HIV)-non-infected adults with drug-susceptible, non-cavitary pulmonary tuberculosis who convert their sputum culture to negative after 2 months of treatment. Secondary objectives of this study include: comparing pre-treatment sputum bacillary load in patients with and without cavitary disease; compare time after inoculation of BACTEC or Mycobacteria growth indicator tube (MGIT) liquid culture media until positive with semi-quantitative sputum acid fast bacteria (AFB) smear and culture on solid media as measures of pre-treatment sputum bacillary load; and determining the influence of immunologic characteristics of subjects pre-treatment, during treatment and at the end of therapy on rate of bacillary clearance and risk for relapse. A total of 758 HIV-non-infected adults, male or female, 18-60 years of age, with newly diagnosed initial episodes of sputum AFB smear-positive or -negative, culture-positive, non-cavitary, drug-susceptible pulmonary TB who are sputum culture negative after 2 months of anti-TB treatment will be randomly assigned to complete a total of 4 or 6 months of anti-TB therapy. The experimental regimen will include a total of 4 months of anti-TB treatment [2 months of daily isoniazid (INH), rifampicin, pyrazinamide and ethambutol followed by 2 months of daily INH and rifampicin]. The comparative regimen will include a total of 6 months standard short course anti-TB chemotherapy (2 months of daily INH, rifampicin, pyrazinamide and ethambutol followed by 4 months of daily INH and rifampicin). Subjects will be involved in study related procedures for approximately 30 months after beginning the initial anti-TB treatment.

Inclusion criteria

-Adults, male or female, aged 18-60. -Newly diagnosed initial episodes of pulmonary tuberculosis. Sputum smear-positive and -negative patients are eligible for enrollment. The diagnosis of tuberculosis must be confirmed by culture. Acid fast bacteria (AFB) smear positive patients found later not to have tuberculosis (TB) (i.e. those with non-tuberculous mycobacterial disease) and those without culture confirmation [at least one culture on solid media growing > 10 colonies of Mycobacterium tuberculosis (MTB) or a positive BACTEC or Mycobacteria growth indicator tube (MGIT) enriched liquid culture growing MTB] will be removed from the study. -Chest X-ray and clinical findings consistent with tuberculosis. -Hemoglobin greater than or equal to 8 gm/dL (greater than or equal to 5.0 mmol/L). -Serum creatinine < 2 mg/dL (< 177 micro mol/L). -Serum aspartate aminotransferase (AST) < 1.5 times the upper limit of normal for the testing laboratory, and serum total bilirubin < 1.3 mg/dL (22.2 micro mol/L). -Random serum glucose less than or equal to 150 mg/dl (8.3 mmol/L). -Ambulatory. -Willing to provide informed consent for study participation, provide required specimens for examination, and to undergo and receive results of human immunodeficiency virus (HIV) testing. -Willing to receive supervised anti-TB treatment. -Completion of the required 112 doses of chemotherapy within 18 weeks of starting treatment.

Exclusion criteria

-Human immunodeficiency virus (HIV)-infected. -History of prior tuberculosis or history of previous tuberculosis treatment. -Pregnant or breastfeeding. -Cavitary tuberculosis on initial chest X-ray (taken within 14 days of study entry). -Exposure to person(s) with known drug resistant tuberculosis. -Patients receiving chronic steroids or other immunosuppressive medications. -Extra-pulmonary tuberculosis. -Patients with drug resistant tuberculosis (resistance to isoniazid (INH), rifampicin, pyrazinamide or ethambutol). -Professional sex worker, alcoholic and/or intravenous (IV) drug abuser. -Silicosis or other serious chronic medical problems including diabetes mellitus or chronic renal failure. Final determination of eligibility will be made after review of drug susceptibility testing results on an initial sputum isolate and results of all sputum cultures. Pregnant patients may not be enrolled in the study. Patients in the 4 month arm who become pregnant during months 5 and 6 of study participation will be dropped from the study and receive an additional 2 months of treatment with INH and rifampicin.