Published On Sep 15, 2015
Superbugs in Their Sights
The Cures Act wants to put more tools in the hands of those who fight drug-resistant bacteria. Can this war be won?
Superbugs—harmful bacteria that are drug-resistant to a dangerous and even deadly degree—are high on the legislative agenda this year. It’s doubtful that a single bill could address every aspect of this complex problem. But this past July, the House of Representatives passed the 21st Century Cures Act, a wide-ranging piece of legislation that aims, among other things, to speed up the pace of drug development and treatment for drug-resistant bacterial infections.
Superbugs have become a growing threat, which may explain the bill’s broad bipartisan support. Each year in the United States, at least 2 million people become infected with antibiotic-resistant bacteria, according to a 2013 report from the Centers for Disease Control and Prevention. At least 23,000 people die as a direct result of these infections.
The CDC report pointed to a family of bacteria that presents one of the most urgent threats to public health: carbapenem-resistant Enterobacteriaceae (CRE), a category of superbug that lives in the gut and has become resistant to last-resort antibiotics called carbapenems. CRE alone now cause more than 9,000 infections in U.S. health care settings each year, and these infections may contribute to death in 50% of patients who get them. Just five years ago, one of the most devious of these CRE was found in the United States for the first time: NDM-1, for New Delhi metallo-beta-lactamase, which is thought to have originated on the Indian subcontinent. NDM-1 is not a bacterium, but an enzyme that allows the bacteria hosting it to break down carbapenems and therefore develop resistance to them. What is most frightening about NDM-1 is that the gene that codes for it can easily hop from one kind of bacteria to another, conferring drug resistance on its new host. That gene sits not on a chromosome, but on what is called a plasmid, a small DNA molecule that can replicate independently. While some NDM-1 varieties can be treated with antibiotics that were more widely used in the 1940s, before the advent of less toxic and more effective drugs, others can’t be treated at all.
So how would the 21st Century Cures Act address something like NDM-1? One provision would allow companies to conduct smaller clinical trials, given that the populations of people with specific drug-resistant bacterial infections are generally still too small to meet requirements that normally call for tens of thousands of patients. It would also require Medicaid to pay for these new, and potentially expensive, drugs when there is no cheaper alternative in a life-threatening situation.
The Cures Act would also increase funding for the National Institutes of Health— which often funds the basic breakthrough science that is later picked up by drug development companies—by about $8.75 billion over the next five years. It would also establish an NIH Innovation Fund and provide more generous loan repayment for young emerging scientists engaging in research.
Not everyone is singing the bill’s praises. Some have criticized the streamlining of any drug’s FDA approval process. And some worry that the bill provides financial incentives to hospitals to prescribe these new antibiotics, which could contribute to overuse—part of what leads to resistance in the first place. Antibiotics are the most commonly prescribed drugs used in human medicine, but up to 50% of all antibiotics prescribed are not needed or are not optimally effective as prescribed.
The Cures Act still has a way to go. The Senate must take up its version of the bill, the Path Act, which differs in many details. But most public health officials agree that something must be done soon. Bacteria evolve quickly, and development of resistance to drugs is a natural part of their evolution. “We’ve seen that throughout history since the 1940s,” says Stephen Calderwood, chief of the Division of Infectious Diseases at Massachusetts General Hospital. “So the only way to address that is to try to stay one step ahead of the evolution of bacterial resistance.”