New TB drugs are more effective and may be less toxic. Why are they still unavailable?

The start of 2017 saw concern over a sharp increase in the rise of drug-resistant TB in South Africa. TB is killing millions each year. Last week, Médecins Sans Frontières published promising early data on the use of two new TB drugs, delamanid and bedaquiline, among patients living with drug-resistant TB in Khayelitsha, Cape Town. But availability remains the biggest concern.