New, shorter tuberculosis treatments could advance control

The introduction of new, shorter treatments for tuberculosis could have a dramatic effect on global efforts to reduce the number of cases and deaths from tuberculosis, according to a new study published in PLoS Medicine.

The current recommended treatment for TB is to give four or more antibiotics for at least six months (this treatment is called "DOTS" or Directly Observed Therapy Short Course--but few patients would agree that taking drugs for 6 months is indeed a "short" course). New TB treatments are currently being tested, and it looks like some of them might be effective when taken for shorter periods. Joshua Salomon (Harvard School of Public Health) and colleagues used a mathematical model to predict what would happen if, instead of having to give a 6-month course, TB could be cured with just a 2-month course of antibiotics.

In Salomon and colleagues' model, a 2-month course led to a quicker fall in the number of new cases of TB each year compared with a 6-month course. Patients who fail to finish a course of treatment can infect others, and it is less likely for patients to drop out of a 2-month course than a 6-month course.

The researchers applied their model to South-East Asia, a region where DOTS is being scaled up and where one-third of all new TB cases occur. They found that even if DOTS is scaled up as planned, a 2-month drug course would still reduce new TB cases and deaths much quicker than a 6-month course.

If, for example, a 2-month drug treatment were introduced by 2012, it might prevent 13% of the new cases and 19% of the TB deaths that would otherwise occur in South-East Asia between 2012 and 2030.

These benefits might be even greater if the new, shorter course treatment freed up financial and human resources to improve efforts to detect new TB cases. On the other hand, delaying its implementation until 2022 would erase three-quarters of the predicted benefits.

Like all mathematical models, this new one makes many assumptions—including the assumption that the experimental TB drugs that are currently being tested can indeed cure TB in 2 months. Nevertheless, Salomon and colleagues' work suggests that the impact of DOTS could be improved by using shorter treatment courses.