At a congressional hearing in Washington, DC on Tuesday, Janet Woodcock, director of the Center for Drug Evaluation and Research (CDER) at the US Food and Drug Administration (FDA), said that current incentives are not enough to overcome the challenges of developing new drugs to fight bacterial infections.
Antimicrobial resistance (AMR) is increasingly being recognized as a global threat to public health. In its 2014 Antimicrobial Resistance: Global Report on Surveillance, the World Health Organization called AMR "so serious that it threatens the achievements of modern healthcare."
More recently, after a Pennsylvania woman was diagnosed with a rare form of colistin-resistant E. coli, US Center for Disease Control and Prevention Director Tom Frieden said "the end of the road isn't very far away for antibiotics," cautioning that once simple-to-treat infections could soon be difficult or impossible to fight with current drugs.
In 2012, to help spur investment into new antibiotics, Congress passed the Generating Antibiotics Now Act (GAIN Act), which introduced the qualified infectious disease product (QIDP) designation for antibiotic and antifungal drugs that treat "serious or life-threatening" infections.
Products with QIDP designation automatically receive priority review from FDA and, if approved, can receive five additional years of marketing exclusivity.
Since the Act's passage, Woodcock said CDER has granted "107 qualified infectious disease product designations to 63 different molecules." Of those, five antibiotics and one antifungal have so far been approved by the agency. Despite this progress, Woodcock says that antibiotic development "needs further examination."
Challenges in Antibiotic Development
According to Woodcock, difficult science and poor return on investment have resulted in a lackluster pipeline for new antibiotic drugs.
"Drug development in this area remains fragile and weak. The incentives that have been put in place are apparently not enough to overcome the scientific challenges that the industry faces in finding new targets and developing these, and then actually making money on them," she said.
As with other drugs, bringing new antibiotics to market requires significant financial investment and time commitment. When asked about these investments, Woodcock cited figures that put the cost of developing new molecular entities from $1 to 2 billion dollars, and said it can take a decade to go from discovery to approval.
However, unlike other drugs, Woodcock said that antibiotics come with a Catch-22. "Once you get them on the market, what everyone will ask [companies] is 'Don't sell them,'" Woodcock said. Hinting at the need for stewardship of such drugs to preserve their effectiveness.
Another issue, according to Richard Hatchett, acting director of the Biomedical Advanced Research and Development Authority (BARDA), is that for antibiotics, "Innovation frequently occurs in small biotechnology companies and in academic laboratories with limited resources and expertise to move product candidates forward." To address this, BARDA announced in February it would launch a new program called the Combating Antibiotic Resistant Bacteria (CARB) Biopharmaceutical Accelerator, in collaboration with the National Institutes of Allergy and Infectious Disease, to "help progress candidate products from the proof-of-concept stage through pre-clinical development."
Furthermore, Woodcock said the basic science of identifying potential candidates for antibiotics is extremely difficult, and that testing those drugs in clinical trials can be logistically challenging.
Emphasizing the challenges, Woodcock raised a number of questions about studying antibiotics in a clinical trial: "How do you find these people who are infected, who are maybe scattered around, and then test a drug in them when they are critically ill and they need to be treated right away? So these clinical trials, even small clinical programs, are extremely challenging."
One solution, proposed in the Antibiotic Development to Advance Patient Treatment Act (ADAPT Act) that was included as part of the 21st Century Cures Act, would be to create a new "limited population" pathway for certain antibiotic and antifungal drugs.
While Woodcock said FDA is interested in such a pathway, she cautioned that drugs approved under it would have "a great deal more uncertainty," and should be reserved for "desperate situations."
According to Woodcock, rapid diagnostics hold great promise against AMR by allowing for less unnecessary antibiotic use and more targeted therapies.
"The technology is advancing…the Center for Devices [and Radiological Health (CDRD)] is seeing technologies come along in the development pipeline, so we expect over the next several years we will see more rapid diagnostic tests in a variety of settings. It's urgent that we try to find some that differentiate bacterial and virus infections," adding that this type of diagnostic could help reassure patients that they do not need antibiotics when they have a viral infection.
To encourage the development of these tests, Woodcock said FDA is working to develop new guidance to support "coordinated development" of diagnostics to go with newly approved antibiotics to help preserve the effectiveness of new antibiotics.