Treating Latent Tuberculosis

Approximately one-quarter of the people in the world have latent tuberculosis infection, with the risk of activation, which can threaten the health of the individual and close contacts. For latent TB infection, 9-months of treatment with isoniazid can prevent active disease. But because of hepatotoxicity and poor completion rates, an equally-effective but shorter and safer treatment protocol is needed. An international, open-label, randomized, Phase 2 – 3 clinical trial was conducted in nearly 7,000 adults with latent TB infection. The trial assessed the non-inferiority of 4-months of oral rifampin to 9-months of oral isoniazid to prevent active TB In the 28-month followup, the 4-month rifampin group had 4 confirmed and 4 clinically-diagnosed active TB cases, and the 9-month isoniazid group had 4 confirmed and 5 clinically-diagnosed active TB cases— a statistically non-significant difference. The 4-month rifampin group had a significantly higher rate of treatment completion than the 9-month isoniazid group. Overall, less than 6% of patients had adverse events, and the 4-month rifampin group had significantly lower rates of Grade 3-5 adverse events, including hepatotoxicity, than the 9-month isoniazid group. The authors conclude that for treatment of adults with latent TB infection, 4-months of rifampin was non-inferior in efficacy to 9-months of isoniazid, with the benefits of improved medication completion and fewer serious adverse events. Full trial results are available at