The US Food and Drug Administration has approved a drug regimen to treat an extreme form of multi-drug resistant tuberculosis (TB).

Nearly 90% of people infected with extensively drug-resistant (XDR) TB that took this treatment recovered in 6 months during clinical trials. The success rate for current drug regimens used to treat XDR TB is around 34%.

One drug in the combination — called pretomanid — is only the third new TB drug to be approved globally in nearly 50 years.

The therapy approved on 14 August, developed by the TB Alliance — a non-profit research group in New York City — consists of pretomanid, along with two other drugs, bedaquiline and linezolid.

Roughly half a million people worldwide are diagnosed with multi-drug resistant TB each year, and about 8.5% of those people have XDR TB, according to the World Health Organization (WHO). Common tuberculosis treatments don’t work on XDR TB, so people with this extreme form of the disease need to take a combination of around eight drugs for at least a year and a half. Even then, the WHO reports that up to two-thirds of people still die from XDR TB.