Cephalexin and Amoxicillin-Clavulanate for Treating Tuberculosis

Early Bactericidal Activity of Cephalexin and Amoxicillin-clavulanate for Susceptible Tuberculosis - BLAST 1 Trial

Phase 2 Interventional Western Sydney Local Health District · NCT05664568

This study is testing if a combination of two antibiotics, cephalexin and amoxicillin-clavulanate, can help adults with active tuberculosis get better faster than standard treatment.

Quick facts

PhasePhase 2
Study typeInterventional
Enrollment30 (estimated)
Ages18 Years and up
SexAll
SponsorWestern Sydney Local Health District Academic / other
Locations3 sites (Sydney and 2 other locations)
Trial IDNCT05664568 on ClinicalTrials.gov

What this trial studies

This randomized controlled trial aims to evaluate the early bactericidal activity of cephalexin combined with amoxicillin-clavulanate in adult patients with smear-positive pulmonary tuberculosis. Participants will be randomly assigned to receive either the combination treatment or standard TB care for two weeks. Throughout the trial, multiple sputum and saliva samples will be collected to assess bacterial load and drug concentrations. The primary outcome will be the reduction in bacterial load measured by the time to positive culture using the BACTEC MGIT system.

Who should consider this trial

Good fit: Ideal candidates are consenting adults aged 18 and older with smear-positive active tuberculosis.

Not a fit: Patients who are already on TB treatment for more than one day or have drug-resistant TB will not benefit from this study.

Why it matters

Potential benefit: If successful, this treatment could provide a more effective and well-tolerated option for patients with tuberculosis.

How similar studies have performed: While this approach is novel in the context of tuberculosis treatment, previous studies have shown the efficacy of these antibiotics against TB bacteria in vitro.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Consenting adults (≥18 years)
* ≥40 kg
* Smear-positive patients with active tuberculosis, confirmed by sputum smear, TB PCR and/or GeneXpert.

Exclusion Criteria:

* On TB treatment for \>1 day
* Condition affecting ability of an informed consent (i.e. dementia, delirium etc).
* Pregnancy or breast-feeding
* HIV
* Known allergy or sensitivity to any of the study drugs
* Drug-resistant TB (resistance to rifampicin and/or isoniazid)
* Poor general condition or severe infection such that, in the opinion of the investigator at screening, any delay in initiation of definitive TB treatment cannot be tolerated
* TB with concomitant central nervous system and/or cardiac involvement.
* Any condition as determined by physical examination, medical history, laboratory data, or chest x-ray which, in the opinion of the investigator, would interfere with safety or endpoint assessments in the study.
* Use of metformin, probenecid or allopurinol
* Known previous Clostridium difficile infection due to the risk of colitis. (In case no medical records are available, it should be suspected in elderly patients reporting severe gastrointestinal infections in relation to courses of antibiotics)

Where this trial is running

Sydney and 2 other locations

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Tuberculosis, PulmonaryRandomized controlled trialEarly bactericidal activitySmear-positive TBBetalactam antibioticsCephalosporinTime to positivity
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.