New antimicrobials: What took so long?
New antimicrobial drugs are needed, as are new policies to improve the regulatory drug approval process. In addition, new incentives are needed to stimulate drug manufacturers to fund antimicrobial clinical trials, which will hopefully lead to new drug products. This month’s column will discuss these new initiatives and several recently labeled antimicrobial drug products.
The FDA and drug approval
The FDA approves the labeling (ie, drug monograph, or package insert) of new drugs, and each year the FDA approves the labeling of more than 100 new drugs, often duplicate therapies of currently existing brand name or generic drug products. These therapies may differ only from currently available products by dose, dosing schedule/duration of action, onset of action, route of administration or other pharmaceutical differences.
Edward A. Bell
Some products, however, represent new chemical structures, and are termed new molecular entities (NME). In 2014, the FDA approved the labeling of 41 novel new drugs (NME or new therapeutic biologic) — the most in nearly 20 years — including four new antibiotics to be discussed below.
New FDA initiatives
Antimicrobial drug products are unique from an economic perspective, with respect to incentives to sponsor and develop new agents by the pharmaceutical industry. Certainly, drug manufacturers prefer to develop products that will be used long term by the patient, for years, or for the patient’s lifetime; for example, drugs for asthma, hypertension or diabetes.
While all drug products are intended to be used judiciously, antimicrobial agents are often specifically targeted for “judicious” use, as a means to limit development of further microbial resistance patterns. Since regulating antimicrobial drug product use equates to reduced profitability for manufacturers, in recent years the FDA has moved to initiate and develop new strategies for incentivizing new antimicrobial drug development and regulatory approval.
A major initiative recently was enacted with the Generating Antibiotics Incentives Now Act (GAIN). Newly developed antibacterial or antifungal agents for life-threatening infectious diseases can be designated as qualified infectious disease products (QIDPs) under GAIN, and in part, may be able to receive priority review and fast-track designation by the FDA. Priority review and fast-track designation are associated with increased and expedited regulatory attention and review of specific new drugs to treat serious, life-threatening disorders. In addition, drugs designated as QIDP may be eligible for an additional 5 years of market exclusivity, which pleases drug manufacturers. Among the six new antimicrobial drugs recently labeled for use, four have been designated as QIDPs.
New antimicrobial drugs
Six new antimicrobial drugs labeled for use in 2014 include: Orbactiv (oritavancin, The Medicines Co.), Sivextro (tedizolid, Cubist), Dalvance (dalbavancin, Durata Therapeutics), Zerbaxa (ceftolozane/tazobactam, Cubist), Rapivab (peramivir, BioCryst Pharmaceuticals), and Xtoro (finafloxacin, Alcon Laboratories). However, only the finafloxacin otic suspension is specifically pediatric-labeled for use in infants/children aged older than 6 months with otitis externa.
Three new antibacterial agents were labeled for use in 2014 to treat skin/skin structure infections in adults. Oritavancin is labeled for IV use in adults with bacterial skin/skin structure infections due to several gram-positive pathogens, including MRSA/MSSA, Streptococcus pyogenes, Enterococcus faecalis (vancomycin-susceptible strains only) and several other streptococcal species. Oritavancin is a lipoglycopeptide that inhibits cell wall synthesis, and, in controlled clinical trials, demonstrated comparable efficacy to vancomycin.
Tedizolid (intravenous and oral dosage forms) was similarly labeled for use in 2014 to treat bacterial skin/skin structure infections in adults.Tedizolid has activity toward MRSA/MSSA, E. faecalis, S. pyogenes and other streptococcal species. Tedizolid is an oxazolidinone antibacterial agent that inhibits bacterial protein synthesis. It was compared with linezolid in controlled clinical trials and was found to be noninferior.
Dalbavancin is the third agent labeled for use in adults for bacterial skin/skin structure infections in 2014. Available for IV administration only, dalbavancin was evaluated in controlled clinical trials and found to be as effective as vancomycin. Classified as a lipoglycopeptide, dalbavancin has demonstrated activity toward MRSA/MSSA, S. pyogenes and several additional streptococcal species.
Ceftolozane/tazobactam was labeled for use in 2014 for adults with complicated intra-abdominal infections and complicated urinary tract infections. In controlled clinical trials ceftolozane/tazobactam plus metronidazole demonstrated similar efficacy as meropenem for complicated intra-abdominal infections and comparable effectiveness as levofloxacin for complicated UTIs. Ceftolozane/tazobactam is a combination product of an anti-pseudomonal cephalosporin and a beta-lactamase inhibitor, and provides activity toward many gram-negative and some gram-positive pathogens, including some species producing extended-spectrum beta-lactamase enzymes.
Peramivir was labeled for use in adults to treat influenza infection in December 2014. Peramivir inhibits influenza viral neuraminidase, as does Tamiflu (oseltamivir, Roche) and Relenza (zanamivir, GlaxoSmithKline). Peramivir is available as an IV dosage form only, and is labeled for one dose, which is unique to the available neuraminidase-class agents. In controlled clinical trials, peramivir demonstrated greater efficacy than placebo and resulted in clinical improvement by approximately 1 day sooner (21 hours) as compared with placebo in individuals with uncomplicated influenza infection and illness.
Finafloxacin otic suspension is a fluoroquinolone topical antibiotic labeled for infants and children aged older than 6 months to treat otitis externa from Pseudomonas aeruginosa or Staphylococcus aureus. Compared with placebo in controlled clinical trials, finafloxacin demonstrated superior efficacy. The availability of finafloxacin increases the product list of agents to treat otitis externa in pediatrics, which includes two other fluoroquinolones (ciprofloxacin and ofloxacin), in addition to otic antibiotic products containing colistin/neomycin or neomycin/polymixin B.
Last year was a banner year for the approval of NMEs by the FDA (see table), the greatest since 1996. Many of the initiatives established by the FDA to improve drug development and approval have benefited clinicians and our patients. The FDA is striving to institute additional changes to improve antimicrobial and drug development that will hopefully improve communication and collaboration among researchers, pharmaceutical manufacturers and federal regulatory bodies.
Jenkins J. CDER Approved Many Innovative Drugs in 2014. FDA Voice. Jan. 14, 2015. http://blogs.fda.gov/fdavoice/index.php/2015/01/cder-approved-many-innovative-drugs-in-2014/
Woodcock J. 21st Century Cures: Examining Ways to Combat Antibiotic Resistance and Foster New Drug Development. Statement Before the Subcommittee on Health, Committee on Energy and Commerce, US House of Representatives. Sept. 19, 2014. http://docs.house.gov/meetings/IF/IF14/20140919/102692/HHRG-113-IF14-Wstate-WoodcockJ-20140919.pdf
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Edward A. Bell, PharmD, BCPS, is professor of pharmacy practice at Drake University College of Pharmacy and Health Sciences and Blank Children’s Hospital and Clinics, Des Moines, Iowa. He also is a member of the Infectious Diseases in Children Editorial Board. Bell can be reached at firstname.lastname@example.org.
Disclosure: Bell reports no relevant financial disclosures.