NCT05473520

Doxycycline Host-directed Therapy to Improve Lung Function and Decrease Tissue Destruction in Pulmonary Tuberculosis

Doxycycline Host-directed Therapy to Improve Lung Function and Decrease Tissue Destruction in Pulmonary Tuberculosis: A Phase III Randomized Control Trial (Doxy-TB)

• Status: Recruiting
• Phase: Phase 3
• Study type: Interventional
• Enrollment: 150 (estimated)
• Sponsor: National University Hospital, Singapore · Academic / Other
• Sex: All
• Age: 21 Years
• Healthy volunteers: Not accepted

Summary

Tuberculosis (TB) is a global pandemic that despite successful treatment and bacterial eradication can cause chronic ill health, such as pulmonary impairment after tuberculosis (PIAT) and cardiovascular disease (CVD). A recent Phase 2b double-blind randomised-controlled clinical trial shows that adjunctive doxycycline therapy is safe, accelerates resolution of inflammation, suppresses tissue damaging enzyme activity and decreases pulmonary cavity volume (1). We aim to determine if adjunctive doxycycline can reduce PIAT and improve cardiovascular outcomes in a fully powered Phase III trial of 8 weeks of adjunctive doxycycline alongside standard pulmonary TB (PTB) treatment. The investigators hypothesize that doxycycline inhibits tissue destruction in patients with PTB and thereby leads to improved lung function after treatment. Specific aims 1. To assess improvement in lung function as measured by forced expiratory volume (FEV1) predicted in PTB patients given doxycycline versus placebo. 2. To investigate whether doxycycline will hasten the resolution of pulmonary cavities measured by CT thorax 3. To investigate whether doxycycline can suppress inflammatory markers including matrix metalloproteinases 4. To investigate whether doxycycline can accelerate time to sputum conversion 5. To evaluate the effect of doxycycline on cardiovascular outcomes such as the incidence of acute coronary syndrome (ACS) and pulmonary hypertension 6. To investigate whether doxycycline improves TB drug concentrations in sputum and plasma. 7. To assess the safety profile of doxycycline with concurrent standard anti-tuberculous treatment.

Detailed description

In this Phase 3 double-blind randomised-controlled trial, doxycycline or placebo shall be given to 75 PTB patients in each arm for two months with a further follow-up of twenty-two months. Study sites are National University Hospital and TB Control Unit in Singapore and Luyang Health Clinic, Menggatal Health Clinic, and Inanam Health Clinic in Sabah, Malaysia. Lung function tests, non-contrast CT thorax, electrocardiograms and transthoracic echocardiograms will be performed at various time intervals. Induced sputum and plasma samples from all PTB patients shall be analysed for matrix metalloproteinases (MMPs), tissue inhibitors of metalloproteinases (TIMPs) and monitored for sputum mycobacteria culture conversion. Whole blood will be analysed by transcriptomics for bulk RNAseq while a subset of patients' blood will be analysed using single-cell RNAsequencing. Blood tests will also be taken for Troponin-I and N-terminal pro-B-type natriuretic peptide. Accomplishing these specific aims will determine if doxycycline decreases PIAT by improving lung function, reducing pulmonary cavities and accelerating sputum culture conversion. We will also be able to assess the effect of doxycycline on development of pulmonary hypertension and acute coronary syndrome. The results will positively impact clinical practice and international guidelines including the World Health Organisation that we collaborate with, for the treatment of pulmonary TB.

Conditions

• Tuberculosis
• Acute Coronary Syndrome
• Pulmonary Hypertension (Diagnosis)

Interventions

Type	Name	Description
DRUG	Doxycycline	A dose of 100 mg twice daily of doxycycline based on the recommended dose for adults which is commonly used for bacterial infections such as rickettsial infection, lyme disease and pelvic inflammatory disease.
DRUG	Placebo	Placebo + standard anti-tuberculous treatment

Timeline

• Start date: 2023-05-24
• Primary completion: 2030-01-31
• Completion: 2030-01-31
• First posted: 2022-07-26
• Last updated: 2025-09-09

Locations

6 sites across 2 countries: Malaysia, Singapore