Evaluating the Pharmacokinetics, Safety, and Tolerability of Bedaquiline in Infants, Children, and Adolescents With Multidrug-Resistant Tuberculosis, Living With or Without HIV

Inclusion Criteria:

1. Less than 18 years old.
2. Parent/legal guardian willing and able to provide written informed consent for study participation; in addition, when applicable per local Institutional Review Board (IRB)/Ethics Committee (EC) policies and procedures, participant is willing and able to provide written assent for study participation.

Age at enrollment:

1. Cohort 1: 6 years of age or older but younger than 18 years of age
2. Cohort 2: 2 years of age or older but younger than 6 years of age
3. Cohort 3: 0 months of age or older but younger than 2 years of age

Weight at enrollment:

1. Cohort 1: At least 15 kg
2. Cohort 2: Greater than 7 kg
3. Cohort 3: At least 3 kg
4. HIV status determined by testing requirements in the protocol.

Either bacteriologically confirmed intrathoracic RR-TB or probable RR-TB and/or extrathoracic TB as listed below:

1. Peripheral TB lymphadenitis
2. Pleural effusion or fibrotic pleural lesions
3. Stage 1 TBM or clinically stable Stage 2A TBM
4. Osteoarticular TB, including spinal TB
5. Other non-disseminated forms of TB disease
6. More information on this criterion can be found in the protocol.
7. Participant is on an RR-TB regimen as per local standard of care for at least seven days and not more than 12 weeks prior to entry, and tolerating the regimen well at entry, as determined by the site investigator based on available medical records.

Note: Participants may have received up to seven doses of non-study BDQ during the seven days prior to study enrollment. The date and dose amount of non-study BDQ doses must be available in medical records

1. For potential participants living with HIV: At least 14 days prior to entry, initiated an acceptable ART regimen defined as zidovudine/lamivudine/abacavir; NVP and two NRTIs; LPV/r and two NRTIs; an integrase class drug including dolutegravir or raltegravir with two NRTIs; or another regimen approved in advance by the Core Team.
2. At entry, the participant has the following laboratory test results according to the DAIDS Table for Grading the Severity of Adult and Pediatric Adverse Events (refer to the protocol for guidance on severity grading):
3. Absolute neutrophil count (normal or grade 1)
4. Creatinine (normal or grade 1)
5. Aspartate Amino Transferase (AST) (normal or grade 1)
6. Alanine Amino Transferase (ALT) (normal or grade 1)
7. Total bilirubin (normal or grade 1)
8. If male and engaging in sexual activity that could lead to pregnancy of the female partner: At entry, participant agrees to use a barrier method of contraception (i.e., male condom) throughout the first 28 weeks on study (i.e., until four weeks after discontinuation of bedaquiline [BDQ]).
9. If female and of reproductive potential, defined as having reached menarche and not having undergone a documented sterilization procedure (hysterectomy, bilateral oophorectomy, or salpingotomy): Negative pregnancy test at screening within five days prior to entry.
10. If female, of reproductive potential (defined in the protocol), and engaging in sexual activity that could lead to pregnancy: Agrees to avoid pregnancy and to use at least two of the following contraception methods throughout the entire period of study participation: condoms, diaphragm or cervical cap, intrauterine contraceptive device (IUCD), hormonal-based contraception. It is required that the method would have had to be initiated at the time of study entry.
11. Among Cohort 3 participants, no documentation that estimated gestational age at birth was less than 37 weeks. Note: Infants born to HIV-infected women will be eligible for enrollment in Cohort 3 regardless of feeding mode and receipt of antiretroviral drugs (ARVs) for prevention of perinatal transmissions.

Exclusion Criteria:

1. A clinically significant active medical condition or concomitant severe (Grade 3 or higher) illness or rapidly deteriorating health condition (excluding TB), including immune deficiency (excluding HIV infection), which, in the opinion of the site investigator, would be worsened by participation in the study or would prevent appropriate participation in the trial, or that would make implementation of the protocol or interpretation of the study results difficult, or otherwise make the participant a poor candidate for a clinical trial.
2. Known or presumed severe extrapulmonary manifestations of TB, including Stages 2B and 3 TBM as determined by the site investigator based on participant/parent/guardian report and/or available medical records.
3. Pregnant or lactating.
4. A significant cardiac arrhythmia that requires medication or a history of heart disease (heart failure, coronary artery disease) that increases the risk for Torsade de Pointes as determined by the site investigator based on participant/parent/guardian report and available medical records.
5. Mean QTcF interval of greater than 460 ms (mean value of QT interval, corrected using Fredericia correction, on electrocardiogram [ECG] performed in triplicate).
6. Clinically relevant ECG changes including but not limited to pathological Q-waves (defined as greater than 40 ms or depth greater than 0.4-0.5 mV); evidence of ventricular pre-excitation; evidence of complete or incomplete left bundle branch block or right bundle branch block; evidence of second or third degree heart block; intraventricular conduction delay with QRS duration greater than 120 ms; age-related bradycardia as defined by sinus rate less than lower limit as indicated in the protocol.
7. Known personal or family history of long QT syndrome.
8. Having participated in other clinical studies with investigational agents or devices, within eight weeks prior to enrollment.
9. Currently taking any of the disallowed medications specified in the protocol. If taking any disallowed medications, a "washout period" of three days or more prior to entry is required.