This is a Phase IIa, open-label, randomized study in treatment-naïve, sputum smear-positive patients with drug-sensitive pulmonary TB to assess the early bactericidal activity of telacebec (Q203).

Inclusion Criteria:

1. A new episode of pulmonary TB determined by testing at the study appointed laboratory: Mycobacterium tuberculosis positive and rifampicin and isoniazid sensitive on a rapid molecular test
2. A chest X-ray taken no more than 14 days before Screening which in the opinion of the Investigator is consistent with TB
3. Sputum smear positive on direct microscopy for acid-fast bacilli on at least 1 pre-treatment sputum sample
4. Ability to produce an adequate volume of sputum as determined by an approximately 16-hour overnight sample collection
5. Be of non-childbearing potential or using effective methods of birth control, as defined in the protocol

Exclusion Criteria:

1. The patient is mentally or legally incapacitated at Screening
2. Any condition or circumstance, in the opinion of the Investigator, which may make the patient unlikely to complete the study or comply with study procedures and requirements, or may pose a risk to the patient's safety
3. Clinically significant evidence of extra-thoracic TB (miliary TB, abdominal TB, urogenital TB, osteoarthritic TB, TB meningitis), as judged by the Investigator
4. The patient has been infected with hepatitis B or C virus as confirmed by tests for hepatitis B core antibodies, hepatitis B surface antigens, and the hepatitis C virus antibodies
5. The patient with history of allergic reaction to isoniazid, rifampicin, pyrazinamide, ethambutol or related substances (eg, tosylate), as confirmed by the clinical judgement of the Investigator