TBTC Study 23A: Pharmacokinetics of Intermittent Isoniazid and Rifabutin in HIV-TB

TBTC Study 23A: Pharmacokinetics of Intermittent Isoniazid and Rifabutin in USPHS Study 23: Treatment of HIV-Related Tuberculosis Using a Rifabutin-Based Regimen

Status

Completed

Phases

Phase 2Phase 3

Study type

Interventional

Source

ClinicalTrials.gov

Registry ID

NCT00023348

Enrollment

150

Registered

2001-09-10

Start date

1999-07-31

Completion date

2002-11-30

Last updated

2005-09-13

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

HIV Infections, Tuberculosis

Keywords

Tuberculosis, TB

Brief summary

Primary Objectives: 1\) To determine the proportion of patients with HIV-related tuberculosis who have abnormal pharmacokinetic parameters for isoniazid and rifabutin. Secondary Objectives: 1. To determine risk factors for abnormal pharmacokinetic parameters for isoniazid and rifabutin. 2. To evaluate the correlation between pharmacokinetic parameters of isoniazid and rifabutin and the occurrence of toxicity attributed to antituberculous therapy. 3. To evaluate the correlation between pharmacokinetic parameters of isoniazid and rifabutin and the efficacy of TB therapy. 4. To define and correlate phenotypic INH acetylator status with the results of genotypic acetylator data obtained in the parent trial.

Detailed description

This study will seek to enroll every eligible patient enrolled in TBTC Study 23. Consenting patients will be asked to undergo measurements of isoniazid (if receiving), rifabutin and 25-OH desacetyl rifabutin levels at a time point in the study when steady state rifabutin levels are expected to have been achieved (at least two weeks following the start of rifabutin).

Interventions

DRUGIsoniazid

DRUGRifabutin

Study design

Allocation

NON_RANDOMIZED

Intervention model

SINGLE_GROUP

Primary purpose

TREATMENT

Masking

NONE

Eligibility

Sex/Gender

ALL

Age

18 Years to No maximum

Healthy volunteers

Inclusion criteria

Inclusion: 1. Patient enrolled in TBTC Study 23 2. Informed consent Exclusion: 1\. Severe anemia (Hct \<25%)

Design outcomes

Primary

Measure	Time frame
To determine the proportion of patients with HIV-related tuberculosis who have abnormal pharmacokinetics of isoniazid and rifabutin.	—

Secondary

Measure	Time frame
1) To determine risk factors for abnormal pharmacokinetics of isoniazid and rifabutin	—
2) To evaluate the correlation between pharmacokinetic parameters of isoniazid and rifabutin and the occurrence of toxicity attributed to antituberculous therapy.	—
3) To evaluate the correlation between pharmacokinetic parameters of isoniazid and rifabutin and the efficacy of TB therapy.	—
4) To define and correlate phenotypic INH acetylator status with the results of genotypic acetylator data obtained in the parent trial.	—

Countries

Canada, United States

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026