As part of the ongoing efforts within the Rapid Research in Diagnostics Development for TB Network (R2D2 TB Network) study, the Candidate Clinical Correlate as Prognostic Outcome for TB (C3PO) study serves as a supplement aimed at evaluating predictors and novel biomarkers of recurrent TB among TB survivors. Current tools for predicting TB recurrence risk are suboptimal, limiting the ability to assess new TB treatment regimens effectively. Identifying accurate sputum- or blood-based biomarkers for recurrence risk could significantly improve the efficiency and informativeness of Phase 2 and 3 clinical trials.

The Candidate Clinical Correlate as Prognostic Outcome for TB Study (C3PO) supplements the ongoing Rapid Research in Diagnostics Development for TB Network (R2D2 TB Network) study by identifying and accelerating novel TB diagnostics at various stages of development and across different use cases. There is an urgent need for treatments that can cure all forms of TB more quickly. However, the development of new, shorter, and more effective antibiotic regimens is hindered by the limitations of current methods used to assess treatment effectiveness in TB drug trials. The standard pharmacodynamic (PD) marker-sputum culture-does not predict clinical outcomes well, fails to detect residual Mycobacterium tuberculosis that causes relapse, and takes 6-8 weeks to provide results. New PD markers that more accurately predict clinical outcomes would help de-risk clinical trials and ensure that only the most effective new regimens move forward. C3PO aims to evaluate non-culture PD markers in predicting recurrent TB among patients who have completed the global standard HRZE regimen for drug-susceptible pulmonary TB under routine programmatic settings.

Inclusion Criteria:

1. . individuals age ≥ 12 years;
2. . have completed treatment for drug-susceptible tuberculosis with the standard 6-month regimen of isoniazid, rifampin, pyrazinamide, and ethambutol (HRZE).

Exclusion Criteria:

1. completed treatment for drug-susceptible tuberculosis >14 days prior to screening/enrollment;
2. routinely taking any medication with anti-mycobacterial activity (including fluoroquinolones) for any reason not related to tuberculosis treatment within the last 14 days;
3. unwilling to provide informed consent or return for study follow-up visits.

The study population consists of individuals receiving programmatic treatment for drug-sensitive tuberculosis (TB) at participating outpatient TB clinics in Uganda and Vietnam. Eligible participants will be selected from among TB patients actively receiving care at these clinical sites.