Shorter TB preventive regimens are safe and effective, study finds

A phase 4 randomized trial in Brazil of 500 people without HIV found one- and three-month isoniazid–rifapentine preventive regimens had high completion rates and mostly mild or moderate adverse reactions.

A phase 4 randomized trial reported in PLOS Medicine evaluated one- and three-month preventive regimens for tuberculosis. The study enrolled people without HIV who had household or occupational exposure to confirmed TB in Rio de Janeiro and Manaus. Both regimens combine isoniazid and rifapentine and are substantially shorter than the traditional six- to nine-month isoniazid course, which has had low uptake and completion historically. The trial focused on treatment completion and safety to address remaining evidence gaps. Key facts: - The trial randomized 500 people aged 15 and older to receive either one month (1HP) or three months (3HP) of isoniazid plus rifapentine. - Primary outcomes were completion of more than 90% of medication and safety events. - Completion rates were 89.6% for 1HP and 84.1% for 3HP. - Adverse reactions were mostly mild or moderate; targeted safety events or treatment discontinuation due to side effects occurred in 16.1% of 1HP recipients and 10.4% of 3HP recipients. - Study authors reported no clear superiority between the two regimens and said the data can inform choices by clinicians and public health officials. Summary: The trial found both 1HP and 3HP achieved high completion and had mostly mild or moderate adverse reactions, with no regimen clearly superior. Undetermined at this time.