A new study shows that rifampin regimen is cheaper than isoniazid for latent tuberculosis

June 17, 2020

Source: MUHC. In a cost-comparison study published on June 16, 2020, in the Annals of Internal Medicine, a team of researchers led by Dr. Dick Menzies, a scientist at the McGill International TB Centre and at the Research Institute of the McGill University Health Centre, found that a four-month rifampin regimen was cheaper than a nine-month course of isoniazid, which is the standard of treatment in most countries for latent tuberculosis infection. This finding adds to previously published evidence that four months rifampin treatment is as effective, while also significantly safer and more likely to be completed, than six months or nine months isoniazid treatment. These findings have the potential to change the way latent tuberculosis is treated.

The team of researchers studied data from two multicenter randomized clinical trials conducted in adults and children with risk factors for developing tuberculosis. They compared health care use and associated costs of treatment with 4 months of rifampin and nine months of isoniazid in these studies. The analysis indicated that latent tuberculosis infection treatment with four months of rifampin resulted in less health service use and significantly lower costs than nine months of isoniazid for both adults and children. These trials included participants from diverse treatment settings in nine countries. According to the researchers, these findings suggest that tuberculosis programs in all countries should consider adoption of the four-month rifampin regimen as a first-line therapy for latent tuberculosis infection.

“In this study, we compared the costs of the two regimens from the perspective of the health system, because policymakers do not look only at regimen effectiveness when adopting new regimens, but also consider affordability,” says Dr. Menzies.

“A major barrier to use of Rifampin for TB prevention is the cost of rifampin pills, which is generally higher than isoniazid pills,” adds Mayara Bastos, the first author of the study. “However, we found that the pills’ costs were offset by reduced health care utilization (e.g., fewer visits and tests) with the shorter regimen – and this was true in low-income and middle-income countries.”

According to the World Health Organization, an estimated one quarter of the global population has latent tuberculosis infection. If left untreated, 10 percent of these 1.7 billion people will develop tuberculosis disease. Latent tuberculosis infection treatment is not new. Monotherapy with isoniazid for six to twelve months has been long proven to reduce the risk for developing active tuberculosis by up to 90 percent. However, the long treatment duration and the fear of serious, even fatal adverse events have limited acceptance and completion.

“There is no time to lose; the evidence base supporting rifampin is strong,” says Dr. Menzies. “We believe that it is time for policymakers and tuberculosis programmes to make four-months of rifampin available as a first-line treatment option for tuberculosis preventive therapy.”

About the study
The study Health System Costs of Treating Latent Tuberculosis Infection With Four Months of Rifampin Versus Nine Months of Isoniazid in Different Settings was conducted by Mayara Lisboa Bastos, MD, MSc, Jonathon R. Campbell, PhD, Olivia Oxlade, PhD, Menonli Adjobimey, MD, MPH, Anete Trajman, MD, PhD, Rovina Ruslami, MD, PhD, Hee Jin Kim, MD, Joseph Obeng Baah, MD, MPH, DThM, Brett G. Toelle, PhD, Richard Long, MD, Vernon Hoeppner, MD, Kevin Elwood, MD, Hamdan Al-Jahdali, MD, Lika Apriani, MD, PhD, Andrea Benedetti, PhD, Kevin Schwartzman, MD, MPH and Dick Menzies, MD, MSc. DOI: https://doi.org/10.7326/M19-3741