August 15, 2019

FDA on Wednesday approved a new antibiotic to treat highly drug-resistant strains of tuberculosis (TB). 

According to the Washington Post, health officials in recent years have raised alarms about the growing threat of drug-resistant bacteria, but few companies are investing in the costly and largely unprofitable undertaking of researching and developing the next generation of antibiotics.

TB is the deadliest infectious disease worldwide, and about 500,000 of the 1.6 million individuals who die annually from TB have a drug-resistant strain of the disease. The United Nations has estimated that infections involving drug-resistant bacteria, including drug-resistant TB, could result in more than 10 million deaths annually by 2050 if steps are not taken to address the rise in drug-resistant bacteria.

FDA approves new antibiotic to treat drug-resistant strains of TB

Given the public health implications, TB Alliance developed the new antibiotic, called pretomanid.

FDA approved pretomanid as part of a three-drug regimen that includes Johnson & Johnson's bedaquiline and linezolid. The regimen is designed to attack multidrug-resistant TB and extensively drug-resistant TB in multiple ways over a six-month period, the Los Angeles Times reports.

FDA noted that, in a clinical trial involving 107 participants with drug-resistant TB, 89% reported successful outcomes after six months of using the three-drug regimen. In comparison, the historical success rate for treating drug-resistant TB is 34%, the Post reports. Data from the clinical trial also showed the three-drug regimen was successful among patients with drug-resistant TB who also are infected with HIV, according to the Los Angeles Times.

TB Alliance expects the treatment to be available in the United States by the end of 2019. TB Alliance in April granted Mylan a license to manufacture and sell pretomanid in high-income markets, as well as a non-exclusive license to manufacture and sell the drug in low-income and middle-incomes countries, where there are a high number of TB cases.

Discussion

TB Alliance CEO Mel Spigelman said the best option for patients with drug-resistant TB until now had been a treatment regimen involving eight types of shots and pills. According to Spigelman, that regimen cured about two-thirds of patients and took about 18 to 30 months, which resulted in many patients dying during the course of treatment. Spigelman estimated that the new treatment regimen could help more than 75,000 patients annually, mostly in China, India, Indonesia, South Africa, and Nigeria.

Jamie Bay Nishi, director of the Global Health Technologies Coalition, in a statement said, "Amazingly, it's the first time that a treatment for [extensively drug-resistant TB] infections has been recognized for actually working—no other treatment has demonstrated any consistent effectiveness."

Matthew Kavanagh, a health policy expert at Georgetown University, said the new antibiotic "could be a major breakthrough" for the tens of thousands of individuals who become infected with drug-resistant strains of TB annually.

But some observers have raised concerns about FDA approving the drug based on limited evidence.

Lindsay McKenna, co-director of the TB project at the Treatment Action Group, in July said, "Pretomanid looks like a promising drug, but it's being rushed forward, and we don't want to see the FDA lower the bar for approval." The Treatment Action Group and other organizations had called on FDA to request more rigorous testing before making a decision on pretomanid.

A new model for drug development?

According to the Los Angeles Times, experts have called the drug's approval a milestone in showing how drugs can be developed without the pharmaceutical industry.

Kavanagh said, "For diseases like [extensively drug-resistant TB], where the market in rich countries is small, new models are especially needed." He said treatments could be less costly if nonprofits begin developing them," adding, "[M]any of the recent new drugs for hard-to-treat diseases are not" affordable for patients.

But Helen Boucher, a professor of medicine at Tufts Medical Center and director of the Tufts Center for Integrated Management of Antimicrobial Resistance, said, "TB is much more narrow and focused and has a precedent in the nonprofit world." She explained, "There isn't a market to sell [a TB drug] to make money, so it was imperative that a nonprofit take that on." In contrast, she noted, "Economists have told us and others that a nonprofit model would not be adequate to meet the needs for the robust and renewable pipeline we need in America" (Rummler, Axios, 8/14; Maddipatla, Reuters, 8/14; Abutaleb, Washington Post, 8/14; Los Angeles Times, 8/14; McNeil, New York Times, 8/14; FDA release, 8/14).

Topics