The FDA has approved pretomanid — the first tuberculosis drug developed by a non-profit organization — as part of a three-drug regimen for the treatment of extensively drug-resistant TB, or XDR-TB, and other resistant forms of the disease.
The combination of pretomanid, Sirturo (bedaquiline, Janssen Therapeutics) and Zyvox (linezolid, Pfizer) has been shown to treat XDR-TB and other highly resistant forms of TB in 6 months, cutting down the current treatment time by at least 12 months.
“In the United States, there are not too many patients that have XDR-TB, but there are some. Now, they will have an option of a 6-month, all-oral treatment with a very high success rate instead of six-plus drugs with a lot of bad side effects and 18 to 24 months of treatment,” Daniel E. Everitt, MD, vice president and senior medical officer at TB Alliance, the drug’s non-profit developer, told Infectious Disease News.
Current treatments for XDR-TB are not only complex, but they are often unsuccessful. In 2015, only about 34% of patients with XDR-TB were successfully treated, according to WHO.
Pretomanid has been studied in 20 clinical trials, both alone and in combination with other anti-TB drugs and has been administered to more than 1,200 people in 14 countries in clinical trial settings. Data from the Nix-TB trial showed that 89% of the first 107 study participants treated with the regimen had a favorable outcome after 6 months of treatment.
Everitt noted that roughly half of the patients in the trial were also HIV-positive and that these patients experienced the same high success rate, adding to the overall positive health impact of the drug.
The FDA accepted a new drug application for pretomanid in March — the first application for approval of the drug submitted in any country. A subsequent application filed with the European Medicines Agency is pending, and other applications are being prepared. In the U.S., it was approved under the Limited Population Pathway for Antibacterial and Antifungal Drugs for patients with XDR-TB or multidrug-resistant TB who are treatment intolerant or nonresponsive.
A member of a class of compounds known as nitroimidazooxazines, pretomanid is only the third new anti-TB drug approved by the FDA in more than 40 years, according to TB Alliance, which is partnering with Mylan to make the drug. Everitt said they will try various methods to keep the cost down.
“Early on, while countries take years to go through the approval process, we’re aiming to have mechanisms where patients won’t have to pay for it. It will be country-by-country how that works, hopefully with some donors covering the cost,” Everitt said. “What we do expect to happen, though, in high-burden countries, is for some other generic manufacturers [to] make a generic version, creating competition and driving down the costs fairly soon after approval.”
Everitt said the drug will have the biggest impact in high-burden, lower income countries like India, South Africa and some former Soviet Union countries, where there is more highly resistant TB. – by Caitlyn Stulpin
Disclosure: Everitt is employed by the TB Alliance.