High-Dose Isoniazid Among Adult Patients With Different Genetic Variants of INH-Resistant Tuberculosis (TB)
- Registration Number
- NCT01936831
- Lead Sponsor
- Advancing Clinical Therapeutics Globally for HIV/AIDS and Other Infections
- Brief Summary
Isoniazid (INH) is a drug commonly used to treat tuberculosis (TB) worldwide. Sometimes, the bacteria that cause TB can become resistant to INH. Resistance means that bacteria have adapted to a drug and are able to live in the presence of the drug. When TB becomes resistant to INH, INH does not work as well at fighting the bacteria. This study treated people with INH-resistant TB with different doses of INH to see if INH can still fight the bacteria if the dose is increased. We evaluated how well the drug works at higher doses for participants who have resistant TB as well as how well the drug works at regular doses for participants who have TB that is not resistant. The study also evaluated the safety and tolerability of the different doses of INH. Tolerability is how well people can put up with the side effects of a drug. Using increased doses of INH to treat TB that is resistant to INH is experimental and has not been approved by regulatory authorities. While there is some evidence that this approach will work, this has not yet been proven.
- Detailed Description
A5312 was a two-stage, two-step, phase IIa, open-label, randomized clinical trial among adult participants with sputum smear positive pulmonary TB evaluating the early bacterial activity (EBA).
No study drug was administered under Step 1. Data collected in Step 1: (a) determined eligibility to Step 2, and (b) allowed characterization of INH MICs in three groups. Groups 1, 2, and 3 consist of participants infected with TB with inhA mutations, with drug susceptible TB (DS-TB), and with TB with katG resistance-conferring mutations, respectively.
Participants enrolled to Step 2 received the study drug, INH, which was given with vitamin B6 \>=25 mg daily, by mouth. During both stages, participants in Group 1 who met Step 2 entry criteria were randomized to receive 5, 10, or 15 mg/kg of INH daily for 7 days. During Stage 2, participants in Group 2 who met Step 2 entry criteria received 5 mg/kg of INH daily for 7 days. Under protocol version 3.0 during Stage 2, participants in Group 3 who met Step 2 entry criteria were randomized to receive 15 or 20 mg/kg of INH daily for 7 days. After completion of 7 days of INH alone, participants were referred to begin standard anti-TB chemotherapy according to local guidelines.
In Step 2, prior to initiation of treatment, sputum was collected for quantitative culture on solid medium (for colony forming units (CFU) for Groups 1 and 2 only) and liquid medium (for determination of time to positivity (TTP) for all groups). Sixteen-hour sputum collections were performed daily during INH treatment, as per standard early bacterial activity (EBA) methodology. Sampling for PK analysis was performed at steady state on Day 6 (±1). Safety and tolerability were monitored via clinical evaluations throughout the study and through scheduled laboratory evaluations.
The study consisted of two stages, as follows:
Stage 1-Pilot study to ensure feasibility:
The goal of Stage 1 was to demonstrate feasibility, not treatment efficacy.
Participants were recruited at a single clinical site. All eligible participants entered Step 1 of the study (determination of INH resistance, measurement of INH minimum inhibitory concentrations (MIC)). Among Group 1 participants who met the Step 2 entry criteria, 15 participants were randomized 1:1:1 to receive 5, 10, or 15 mg/kg daily of INH for 7 days with evaluations performed as described above.
Stage 1 completed March 26, 2015. A total of 15 Group 1, 44 Group 2, and 12 Group 3 participants were enrolled in Step 1 only during Stage 1. These participants did not receive study treatment. They provided sputum samples for MIC determination.
Stage 2-Main study:
During Stage 2, Group 1 participants who met Step 2 entry criteria were randomized 1:1:1 to receive 5, 10, or 15 mg/kg of INH daily for 7 days. Group 2 participants who met Step 2 entry criteria were enrolled and received INH at a dose of 5 mg/kg daily. Group 3 participants who met Step 2 entry criteria were enrolled and randomized 1:1 to receive INH at a dose of 15 or 20 mg/kg daily.
In Stage 1, Group 1 participants who did not meet Step 2 entry criteria, all Group 2 participants and all Group 3 participants were referred to a local TB program for treatment. In Stage 2, Group 1, 2 and 3 participants who did not meet Step 2 entry criteria, were referred to a local TB program for treatment.
Protocol Versions:
Key differences in protocol versions include the following:
* Study entry criteria were changed from protocol versions 1.0 to 2.0
* No longer excluded individuals for antiretroviral therapy use
* Exclusion of individuals with any MDR-TB treatment with second-line anti-TB drugs was relaxed to exclude only those with more than 7 cumulative days of use.
* Protocol version 2.0 allowed additional sites to enroll participants.
* Under protocol versions 1.0 and 2.0, eligible individuals in Group 1 and Group 2 could enroll in Step 1 and Step 2, and eligible individuals in Group 3 could be enrolled in Step 1 only. Under protocol version 3.0, eligible individuals in Group 3 could enroll in Step 1 and Step 2.
* Early bactericidal activity was described using both solid culture CFU and liquid culture TTP under protocol versions 1.0 and 2.0. Under protocol version 3.0, early bactericidal activity was measured by liquid culture TTP only.
* There were technical difficulties with measuring the isoniazid minimum inhibitory concentration using 1% agar solution for participants enrolled under protocols versions 1.0 and 2.0. For protocol version 3.0, the Thermo Fisher MYCOTB Sensititre plate was substituted to overcome the technical difficulties.
Recruitment & Eligibility
- Status
- COMPLETED
- Sex
- All
- Target Recruitment
- 282
Not provided
Not provided
Study & Design
- Study Type
- INTERVENTIONAL
- Study Design
- PARALLEL
- Arm && Interventions
Group Intervention Description Group 1: 5mg Cohort Isoniazid Group 1 participants had an M. tuberculosis strain with an inhA mutation only. 5 mg cohort received Isoniazid 5 mg/kg daily plus vitamin B6 \>=25 mg daily for 7 days Group 1: 5mg Cohort Vitamin B6 Group 1 participants had an M. tuberculosis strain with an inhA mutation only. 5 mg cohort received Isoniazid 5 mg/kg daily plus vitamin B6 \>=25 mg daily for 7 days Group 1: 10mg Cohort Isoniazid Group 1 participants had an M. tuberculosis strain with an inhA mutation only. 10 mg cohort received Isoniazid 10 mg/kg daily plus vitamin B6 \>=25 mg daily for 7 days Group 1: 10mg Cohort Vitamin B6 Group 1 participants had an M. tuberculosis strain with an inhA mutation only. 10 mg cohort received Isoniazid 10 mg/kg daily plus vitamin B6 \>=25 mg daily for 7 days Group 1: 15mg Cohort Vitamin B6 Group 1 participants had an M. tuberculosis strain with an inhA mutation only. 15 mg cohort received Isoniazid 15 mg/kg daily plus vitamin B6 \>=25 mg daily for 7 days Group 1: 15mg Cohort Isoniazid Group 1 participants had an M. tuberculosis strain with an inhA mutation only. 15 mg cohort received Isoniazid 15 mg/kg daily plus vitamin B6 \>=25 mg daily for 7 days Group 2: 5mg Cohort Vitamin B6 Group 2 participants had an M. tuberculosis strain with neither inhA nor katG mutations. All Group 2 participants received Isoniazid 5 mg/kg daily plus vitamin B6 \>=25 mg daily for 7 days Group 3: 15mg Cohort Vitamin B6 Group 3 participants had an M. tuberculosis strain with a katG mutation with or without an inhA mutation. 15mg cohort received Isoniazid 15 mg/kg daily plus vitamin B6 \>=25 mg daily for 7 days Group 3: 20mg Cohort Vitamin B6 Group 3 participants had an M. tuberculosis strain with a katG mutation with or without an inhA mutation. 20mg cohort received Isoniazid 20 mg/kg daily plus vitamin B6 \>=25 mg daily for 7 days Group 2: 5mg Cohort Isoniazid Group 2 participants had an M. tuberculosis strain with neither inhA nor katG mutations. All Group 2 participants received Isoniazid 5 mg/kg daily plus vitamin B6 \>=25 mg daily for 7 days Group 3: 15mg Cohort Isoniazid Group 3 participants had an M. tuberculosis strain with a katG mutation with or without an inhA mutation. 15mg cohort received Isoniazid 15 mg/kg daily plus vitamin B6 \>=25 mg daily for 7 days Group 3: 20mg Cohort Isoniazid Group 3 participants had an M. tuberculosis strain with a katG mutation with or without an inhA mutation. 20mg cohort received Isoniazid 20 mg/kg daily plus vitamin B6 \>=25 mg daily for 7 days
- Primary Outcome Measures
Name Time Method Daily Change in log10 Colony-forming Unit (CFU) Measured at baseline and Day 7 Negative daily change in log10 CFU indicate decreases in bacterial burden over the 7 day period. Defined as EBA0-7(CFU) = \[Day 7 log10 CFU per mL - baseline log10 CFU per mL\]/7. The baseline measure is the mean of the pre-entry visit and entry visit sputum colony counts.
Daily Change in Time to Positivity (TTP) Measured at baseline and Day 7 The time to positivity (TTP) measures growth of mycobacterium tuberculosis using MGIT assay in hours. Higher values of daily change in TTP indicate greater decrease in bacterial burden over the 7 day period and is therefore better.
Daily change is defined as EBA0-7(TTP) = \[Day 7 TTP - Baseline TTP\]/7. Baseline is the mean of the pre-entry visit and entry visit TTPs.INH PK Parameter Area Under the Concentration Time Curve (AUC 0-24 Hours) Intensive INH PK samples collected on Day 6 of INH initiation at sample times pre-dose, 0.5h, 1h, 2h, 4h, 6h, 8h, 12h and 24h post-dose. AUC 0-24h defines area under the concentration-time curve over the period of 24 hours post-dose, estimated through non-compartmental methods using the linear trapezoidal rule.
Number of Participants With Grade 2 or Higher Drug-related Adverse Clinical or Laboratory Events Measured from entry through Day 21 Post-entry, all new diagnoses, signs/symptoms and laboratory events of ≥Grade 2 that were assessed by the site as drug related. The DAIDS AE Grading Table (V1.0) and EAE Manual (V2.0) were used.
- Secondary Outcome Measures
Name Time Method INH PK Parameter Minimum Plasma Concentration (Cmin) Intensive INH PK samples collected on Day 6 of INH initiation at sample times pre-dose, 0.5h, 1h, 2h, 4h, 6h, 8h, 12h and 24h post-dose. Cmin defines minimum concentration observed over the 24 hours of the INH dosing interval.
INH PK Parameter Maximum Plasma Concentration (Cmax) Intensive INH PK samples collected on Day 6 of INH initiation at sample times pre-dose, 0.5h, 1h, 2h, 4h, 6h, 8h, 12h and 24h post-dose. Cmax defines maximum concentration observed over the 24 hours of the INH dosing interval.
INH Minimum Inhibitory Concentration (MIC) Against M. Tuberculosis Isolates Day 0 MIC are determined by phenotypic drug susceptibility testing (DST) based on spot sputum collected at Step 1 Day 0. For group 3 participants shown, MIC was tested using Thermofisher Sensititre MYCOTB plates.
Proportions of Participants Estimated to Have a Drop in log10 CFU/mL at or Above 0.65 log10 CFU/mL. From baseline through day 7 Proportions of participants obtained through simulation using the estimated model who have a drop in log10 CFU/mL at or above the threshold of 0.65 log10 CFU/mL; 0.65 is half the drop in log10 CFU/mL observed in participants with DS-TB (Group 2) on day 7. A total of 10000 simulated pseudo-participants per arm were used based on data from the study participants. The NAT2 genotype distribution was based only on Group 1 and 2 participants since NAT2 genotype data was not available for Group 3. The simulations were run repeatedly. The point estimate of the proportion was based on the median proportion of the pseudo-individuals across the repeated simulations and the 90% confidence interval used the 5th and 95th percentiles of the proportion across the repeated simulations.
Daily Change in log10 CFU Measured by Early- (EBA0-2) and Late-phase (EBA2-7) Individual-based Parameter Estimates From Nonlinear Models At baseline, day 2, and day 7 Negative daily change in log10 CFU indicate decreases in bacterial burden over the time period. The mean CFU are estimated using all values by fitting a biphasic regression models for each participant. The daily change for the first two days of treatment was calculated as EBA0-2 (CFU)= \[Day 2 log10 CFU per mL - baseline log10 CFU per mL\]/2. The daily change from day 2 to day 7 was calculated as EBA2-7 (CFU)= \[Day 7 log10 CFU per mL - Day 2 log10 CFU per mL\]/5. Baseline is the average of pre-entry and entry visits.
Daily Change in TTP Measured by Early- (EBA0-2) and Late-phase (EBA2-7) Individual-based Parameter Estimates From Nonlinear Models At baseline, day 2, and day 7 The time to positivity (TTP) measures growth of mycobacterium tuberculosis using MGIT assay in hours. Higher values of daily change in TTP indicate greater decrease in bacterial burden over the time period and is therefore better. The mean log transformed TTP are estimated using all values by fitting a biphasic regression models for each participant. The daily change over the first two days of treatment is calculated as EBA0-2 (TTP)= \[Day 2 TTP - baseline TTP\]/2. The daily change from Day 2 to Day 7 is calculated as EBA2-7 (TTP)= \[Day 7 TTP - Day 2 TTP\]/5. Baseline is the average of pre-evaluation and entry visits.
EBA Measured by Individual-based Parameter Estimates From Linear or Nonlinear Models When the Number of Phases Differs Between Every Dosing Cohort From baseline through day 7 Both TTPs and log10 CFU from the pre-evaluation and entry visits averaged and treated as the baseline TTP and log10 CFU for each participant. This outcome was included for analysis if the number of phases differed between every dosing cohort. Since the number of phases did not differ between dosing cohorts, this outcome was not measured.
Mean EBA Measured by Ratio of the Following Areas: Numerator = AUC of Observed log10 CFU Over 7 Days and Denominator = Baseline log10 CFU for Every Dosing Cohort in Groups 1 and 2 From baseline through day 7 This approach utilizes the area between baseline CFU per mL and the CFU curve for each participant, as measured using the trapezoidal rule. This outcome was included for analysis if the number of phases differed between every dosing cohort. Since the number of phases did not differ between dosing cohorts, this outcome was not measured.
Trial Locations
- Locations (2)
GHESKIO Institute of Infectious Diseases and Reproductive Health (GHESKIO - IMIS) CRS (31730)
🇭🇹Port Au Prince, Haiti
TASK Applied Science CRS (31718)
🇿🇦Bellville, South Africa