Book excerpt: WHO estimates that up to half a million new cases of multidrug-resistant tuberculosis (MDR-TB) occur worldwide, each year. Current treatment regimens for MDR-TB present many challenges: treatment lasts 20 months or more, requiring daily administration of drugs that are more toxic, less effective, and far more expensive than those used to treat drug-susceptible TB. Globally, less than half of all patients who start MDR-TB therapy are treated successfully. For the first time in over 40 years, a new TB drug with a novel mechanism of action - bedaquiline- is available, and was granted accelerated approval by the United States Food and Drug Administration in December 2012. There is considerable interest in the potential of this drug to treat MDR-TB. However, information about this new drug remains limited. It has only been through two Phase IIb trials for safety and efficacy. The World Health Organization (WHO) is therefore issuing "interim policy guidance". This interim guidance provides advice on the inclusion of bedaquiline in the combination therapy of MDR-TB in accordance with the existing WHO Guidelines for the Programmatic Management of Drug-resistant TB (2011 Update).