A Phase 4 operational study to assess the effectiveness, feasibility, acceptability, and cost effectiveness of the GeneXpert MTB/XDR (Xpert XDR; Cepheid) assay for rapid triage-and-treatment of DR-TB-A multi-centre, multi-country prospective cohort study
The TriAD study is a multi-center, multi-country Prospective Pragmatic Cohort study assessing the effectiveness, feasibility, acceptability, and cost-effectiveness of implementing the Xpert MTB/XDR (Xpert XDR; Cepheid) assay for rapid triage-and-treatment with short, all- oral drug resistant tuberculosis (DR-TB) treatment. The proposed study aims to screen approximately 4800 GeneXpert MTB/RIF or Ultra MTB-positive (irrespective of rifampicin resistance status) patients from 9 study sites in South Africa, Nigeria and Ethiopia to enrol 880 rifampicin resistant (RR) and 400 isoniazid mono-resistant (HR) patients over a period of 12-18 months. The Xpert XDR assay, a rapid genotypic test, will be implemented as a reflex test to detect resistance to isoniazid, fluoroquinolones and second-line injectable agents to provide rapid genotypic susceptibility testing for DR-TB detection. Patients that test positive for Mycobacterium tuberculosis with rifampicin resistance will be enrolled in Cohort 1 (n=880). Patients that test positive for Mycobacterium tuberculosis that are rifampicin susceptible with isoniazid mono-resistance will be enrolled in Cohort 2 (n=400). Results from the Xpert XDR assay will be used to guide selection of appropriate, evidence-based, all-oral DR-TB treatment regimens of shortest possible duration. The tuberculosis molecular bacterial load assay (TB-MBLA) will be used as an adjunct to provide bacillary load monitoring over the course of treatment to assess real-time treatment response. Operational research will provide information about the feasibility, acceptability and cost-effectiveness to inform policies and guidelines for programmatic implementation of the triage-and-treat model.
Study Type
OBSERVATIONAL
Enrollment
786
The Xpert MTB/XDR Assay, performed on the GeneXpert Instrument Systems, is a nested real-time polymerase chain reaction(PCR) in vitro diagnostic test for the detection of extensively drug resistant (XDR) Mycobacterium tuberculosis (MTB) complex DNA in unprocessed sputum samples or concentrated sediments prepared from sputum. In specimens where MTB is detected, the Xpert MTB/XDR Assay can also detect isoniazid (INH) resistance associated mutations in the katG and fabG1 genes, oxyRahpC intergenic region and inhA promoter; ethionamide (ETH) resistance associated with inhA promoter mutations only; fluoroquinolone (FLQ) resistance associated mutations in the gyrA and gyrB quinolone resistance determining regions (QRDR); and second line injectable drug (SLID) associated mutations in the rrs gene and the eis promoter region.
Ethiopian Public Health Institute (EPHI)
Gulele, Addis Ababa, Ethiopia
Institute of Human Virology Nigeria
Yaba, Lagos, Nigeria
CAPRISA Springfield Research Clinic
Durban, KwaZulu-Natal, South Africa
Clinical HIV Research Unit (CHRU), WITS Health Consortium
Bethelsdorp, Port Elizabeth, South Africa
Time to initiation
Time to initiation of an appropriate all oral treatment regimen from date of first sputum collected
Time frame: 4 years
Proportion of patients with favorable treatment outcomes
Proportion of patients with favorable treatment outcomes at month 12 from diagnosis
Time frame: 4 years
Adverse Drug Reactions
Incidence of adverse drug reactions documented during all oral treatment
Time frame: 4 years
Mortality
All cause mortality documented during treatment and follow up
Time frame: 4 years
Time to culture Conversion
Time specific rates of culture conversion
Time frame: 4 years
HR TB Prevalence
Prevalence of HR TB (cohort 2)
Time frame: 4 years
XDR TB Prevalence
Prevalence of XDR TB (cohort 2)
Time frame: 4 years
Proportion of patients with Bedaquiline and linezolid resistance not eligible for short course treatment
Proportion of patients with Bedaquiline and linezolid resistance not eligible for short course treatment
Time frame: 4 years
Clinical utility of the Tuberculosis Molecular Bacterial Load Assay (TB-MBLA) compared to routine culture to monitor DR-TB treatment response
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Quantitative results from the TB-MBLA, a real-time quantitative PCR (RT-qPCR) assay, that detects and quantifies killing of 16S rRNA from both viable replicating and dormant M. tuberculosis in patient sputum during treatment, will be compared to routine culture in monitoring treatment response
Time frame: 4 years
Feasibility of Tuberculosis Molecular Bacterial Load Assay (TB-MBLA) will be compared to routine culture in bacteriological follow-up for people on DR-TB treatment
Feasibility of TB-MBLA Assessed by comparison to liquid culture with respect to accuracy, result turn-around time, failure rates.
Time frame: 4 years
Accuracy of Xpert XDR testing compared to WGS
The performance of Xpert XDR will be compared to Culture DST, LPA and Next Generation Sequencing.
Time frame: 4 years
Quality of Xpert XDR testing
Quality of Xpert XDR testing will be assessed using: 1. indeterminate rates measured by the number of Xpert XDR tests regarded as invalid divided by the total number of Xpert XDR tests performed 2. Contamination rates or frequency of DNA contamination: number of Xpert XDR tests flagging contamination divided by the total number of Xpert XDR tests performed or events 3. performance variation will be measured by performance in discrimination of (i) INH resistance compared to culture across study sites, (ii) aminoglycoside resistance compared to culture across study sites and (iii) fluroquinolone resistance compared to culture across study sites
Time frame: 4 years
Resistance profile of sputum samples for identification of drug resistance mutations as per pre-existing probes within the Xpert XDR assay
Cultured isolates from the same sputum sample will undergo WGS sequencing to identify additional resistance mutations to new and re-purposed drugs. The endpoints measured for this objective includes: 1. Frequency of detection of additional resistance conferring mutations by WGS not detected by Xpert XDR 2. Impact of these previously undetected mutation on conferring resistance to the new drugs in the bedaquiline, pretomanid and linezolid regimen
Time frame: 4 years
Cost effectiveness
Data for Costing studies will be collected through semi-structured interviews of key informants and document review. Methods will include a construction of incremental cost effectiveness ratios (ICER) and CE-model to estimate the costs and benefits from a societal perspective, generalizable to other settings. timely initiated on treatment
Time frame: 4 years
Operational Feasibility of patient triaging
The Operational Cost including Infrastructure and Human resource requirements for the study approach.
Time frame: 4 years