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Associate Professor
Nesri Padayatchi

South Africa

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Project Title

Improving retreatment success of tuberculosis

Project Objectives

To determine if a moxifloxacin-containing regimen [isoniazid (H), rifampin (R), pyrazinamide (Z), moxifloxacin (M)] of 24 weeks duration is superior to a control regimen [isoniazid (H), rifampicin(R), pyrazinamide(Z), ethambutol(E)] of 32 weeks duration in improving treatment outcomes in patients with recurrent TB

Host Organisation

Department Institution Country
University of KwaZulu-Natal (UKZN) South Africa

EDCTP Project

TA.2011.40200.044

EDCTP Program

EDCTP1

EDCTP Project Call

Senior Fellowship (SF)

Study Design

Randomised controlled trial

Sites

Project Title

The Individualized Multi-/Extensively Drug-Resistant Tuberculosis Treatment Strategy Study (InDEX)

Project Objectives

Primary Objective To determine whether a gene-derived individualized treatment approach improves culture-negative survival at 6 months post-treatment initiation in patients with drug-resistant TB. Secondary Objectives · Develop and refine a protocol for extracting Mycobacterium tuberculosis (MTB) DNA directly from sputum for WGS. · Compare resistance mutations detected by WGS with conventional diagnostic methods (e.g., GeneXpert, Line Probe Assay). · Design and evaluate a clinical decision-making algorithm for interpreting and acting on resistance mutation data.

Results & Outcomes

value="value="value="value="value="value="value="value="value="value="value="value="value="value="value="value="value="value="value="value="value="WGS Implementation · Median time to WGS-informed treatment: 74 days (IQR: 60–107 days) · WGS data were available for 100 participants · Of these, 66% required changes to their initial regimen: o 60% had ≥1 drug added o 40% had ≥1 drug removed Clinical Outcome · Culture-negative survival at 6 months: o WGS arm: 91% (93/102; 95% CI: 83–96%) o SOC arm: 92% (95/103; 95% CI: 85–96%) o p = 0.8 No statistically significant difference. """""" "While WGS did not improve 6-month culture-negative survival compared to standard care, it enabled meaningful regimen optimization in the majority of cases, particularly for patients with more complex drug resistance: · 74% of MDR-TB and 77% of XDR-TB regimens were informed by WGS. · These findings highlight the limited utility of pDST in the era of genomic-guided treatment. The delayed availability of culture-based WGS results likely limited its impact. Future research should explore direct sputum sequencing to shorten turnaround times and increase clinical utility. "The InDEX study has had wide-reaching impacts beyond clinical outcomes: · Strengthened South Africa’s research infrastructure, including sample biobanking, data management, and ethics compliance. · Promoted collaborative research culture across clinical and laboratory teams. · Contributed to policy translation, with WGS findings informing TB control strategies. National Uptake · In late 2024, based on growing evidence, the South African Department of Health began integrating WGS into national TB guidelines. · King Dinuzulu Hospital in Durban is partnering with the National TB Programme, under Dr. Norbert Ndjeka, to pilot WGS-informed TB care in programmatic settings."""""""""""""""

Host Organisation

Department Institution Country
Centre for the Aids Programme of Research in South Africa (CAPRISA) ZA

EDCTP Project

TMA2018SF-2467

EDCTP Program

EDCTP2

EDCTP Project Call

Senior Fellowship (SF)

Study Design

Randomized control trial

Project Summary

Drug-resistant tuberculosis (DR-TB) remains a major global health challenge, undermining the goal of eliminating TB as a public health threat by 2035. Over the past 15 years, the global incidence of multidrug- and extensively drug-resistant TB (M/XDR-TB) has more than doubled. In South Africa, this crisis is exacerbated by its convergence with the HIV/AIDS epidemic. The current gold standard for determining drug resistance, phenotypic drug susceptibility testing (pDST), has long turnaround times, which results in delayed treatment decisions. In practice, patients are often started on sub-optimal empiric regimens that may be ineffective and associated with unnecessary adverse effects. The InDEX Study aimed to address this gap by evaluating whether a whole genome sequencing (WGS)-based approach could improve clinical outcomes through earlier, individualized treatment adjustments based on drug resistance mutations. A randomized controlled clinical trial was conducted between May 2017 and December 2022, enrolling 205 participants with confirmed M(X)DR-TB: · 103 participants were assigned to the Standard of Care (SOC) arm. · 102 participants were assigned to the WGS-guided intervention arm. Participant Characteristics · Median age: 35 years · 41% female · 71% HIV-positive, of whom 62% were on ART at TB diagnosis All experimental activities, including sample collection, WGS, and treatment modifications based on WGS findings, were completed within the project period. The study significantly advanced local scientific capacity and contributed to global TB research expertise: · Training Outputs: o 2 Master’s students o 1 PhD candidate o 1 postdoctoral fellow o 1 early-career scientist · Dissemination: o 13 peer-reviewed publications o 11 scientific conference presentations o Ongoing mentoring and manuscript development · Cross-project collaboration within CAPRISA and with other EDCTP-supported scientists facilitated co-supervision and knowledge transfer. I also fostered collaboration between scientists at the National Institute of Communicable Diseases, and the Lung Institute at the University of Cape Town.