Study finds that common antibiotics can help in curing tuberculosis

A clinical trial of 30 patients led by researchers at the Yang Loo Lin School of Medicine showed that doxycycline, combined with tuberculosis treatment, reduced lung cavity size and increased other markers of recovery.

The findings were published in the Journal of Clinical Investigation

Globally, an estimated 10 million people develop tuberculosis (TB) each year, and the disease remains the leading cause of death from a single infectious source. Standard short-course anti-TB treatment still requires at least six months of antimicrobial therapy, and drug-resistant TB is a growing public health threat.

Even when traces of TB are eliminated, patients often suffer severe sequelae, such as scarring of the lungs. The mortality rate among TB survivors is approximately three to four times that of the local population.

Tuberculosis is the most common form of active TB, and Mycobacterium tuberculosis causes the formation of sites of high bacterial load, known as cavities. TB drugs have difficulty penetrating these cavities.

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After TB treatment is completed, tissue damage may occur in the lungs, leading to further lung problems such as permanent respiratory dysfunction leading to difficulty breathing, lung stiffness, and bronchiectasis that can lead to coughing up blood.

In a phase 2 double-blind trial conducted at the National University Hospital and the Tuberculosis Control Center, the treatment was found to be safe, with side effects similar to those in patients taking placebo pills. The study shows promise in providing a new standard of care with the potential to prevent long-term complications, and the research team is seeking funding for a comprehensive, larger Phase 3 trial to validate these findings.

“Patients with TB tend to suffer lung damage after TB, which is associated with mortality and poorer quality of life. Doxycycline, a cheap and widely available antibiotic, can reduce lung damage and potentially improve quality of life in these patients,” said Assistant Professor Catherine Ong, the study’s lead researcher and a member of the Translational Research Program (TRP) in Infectious Diseases at the National University of Singapore’s Faculty of Medicine.

Professor Paul Tambyah, Deputy Director of Infectious Diseases at TRP, who was involved in the study, commented: “While we have successfully treated the majority of TB cases over the past few decades, we have seen many people suffer complications from lung damage as a result of the original TB infection. If doxycycline, a common drug, can help prevent the complications of ‘long-term TB’ (the current popular term), this will really help many patients in Singapore and around the world.”

The Infectious Diseases TRP aims to provide a holistic, patient-centred approach to infectious diseases relevant to Singapore and the region. The program focuses on programmatic research areas including pathogen evolution and transmission, host-microbe interactions, and vaccine and therapeutic development.