Tuberculosis (TB) is a serious and contagious infection that most commonly affects the lungs. Latent TB means the person has the infection but is not ill yet. Patients with latent TB are often given an antibiotic treatment to prevent active TB from developing. Treating latent TB has advantage of eliminating the infection before it makes the patient sick and before it becomes contagious. Unfortunately, the treatment is a long course of daily antibiotics over nine months. For many people a long course of antibiotic when you aren't experiencing symptoms can lead to low treatment completion rates (30%-64%). As with any antibiotic treatment, it is important for the entire treatment to be completed to eliminate the bacteria and decrease risk of developing antibiotic resistant strains of TB.

Researchers investigated the benefits of a shorter course of antibiotics with rifapentine and isoniazid compared to standard nine month treatment with isoniazid alone in patients with latent TB at high risk of progression of disease. The trial, published in the New England Journal of Medicine, found that the shorter combination therapy was as effective as long-term therapy at preventing development of TB.

About the Study

The randomized trial included 8,053 patients with latent TB. The patients were randomized to receive one of two treatment options:

  • Directly-observed administration of rifapentine 900 mg plus isoniazid 900 mg once weekly for three months (healthcare team watched patients take treatment)
  • Self-administered isoniazid 300 mg once daily for nine months

After 33 months, TB developed in

  • 0.19% with three month treatment vs. 0.43% with nine month treatment
  • 0.1% with three month treatment vs. 0.2% with nine month treatment in patients who completed all medicine doses

The three month treatment with the two drugs led to less need to stop medicines due to adverse events. It also made it more likely that the patients would complete the entire treatment.

How Does This Affect You?

This trial was a large randomized trial, which means the results are considered reliable. The Centers for Disease Control and Prevention (CDC) added a recommendation to their TB guidelines based on this trial. The CDC now recommends isoniazid plus rifapentine over three months with directly observed therapy as an alternative to isoniazid once daily for nine months in otherwise healthy patients who are 12 years of age or older with latent TB at risk for developing TB.

The shorter dose with combination of rifapentine and isoniazid appears as effective as nine month course of isoniazid. Decreasing the length of treatment may make it much easier to fully complete treatment, although the shorter dose requires observation by medical professionals. In this study, the combination of rifapentine and isoniazid was also related to fewer incidences of severe adverse events requiring treatment to be stopped. Latent TB may be found during a TB screening. If you are diagnosed with latent TB, talk to your doctor about your risk factors for developing active TB and which treatment options may be best for you.