15 years of FDA and antibiotics

Geni Wren Consumer media seems to like to point fingers at the FDA for what they believe is inaction on the use of antibiotics in food animals. But Rich Carnevale, VMD, Animal Health Institute, says the FDA has taken many actions regarding food animal antimicrobials in the last 15 years.

“Antimicrobial use in food animals has been debated for 40 years,” Carnevale told participants at the National Institute for Animal Agriculture 2012 Antibiotic Symposium in Columbus, Ohio. “There are mountains of literature. Regulatory policy has been shaped over this time, leading to a relatively restrictive regulatory environment.” One example is Guidance No. 152.

Carnevale offered this timeline of regulatory action in the arena of food animal antimicrobials:

1988 -- FDA requires that all new antibiotics must be approved only as prescription drugs, no more over-the-counter labeling

1995 – Veterinary Feed Directive (VFD) was instituted for animal antimicrobials used in feed.

1996 – National Antimicrobial Resistance Monitoring System implemented to track resistance

1997 -- FDA publishes the “no Extralabel Drug Use” (ELDU) list

2003 – Guidance #152 is released that discusses a qualitative “risk assessment” that all new products must go through

2008 – Guidance #209 is released that would phase out “medically important” antibiotics

2011 – Cephalosporins are added to the ELDU

2012 – Guidance #213 would phase out growth promotion and move those “medically important “antibiotics to the VFD

2012 -- Changes to the VFD regulation are proposed

Recent developments in food animal antibiotics over the past several years include:

• All antibiotics that have been recently approved are for short duration, prescription only or for use under the VFD
• No products have been approved for herd/flock administration
• Two products have been withdrawn (fluoroquinolones in poultry)
• One product has been rejected by an FDA advisory committee (cefquinone)
• Two classes have been restricted for ELDU (fluoroquinolones & cephalosporins)

New antibiotics in the last 15 years
There have been a few antibiotics approved for food animals in the last 15 years, and those products  are highly targeted and for very specific uses, Carnevale noted. These include:

• Enrofloxacin, approved for beef cattle and swine for BRD and SRD
• Florfenicol, approved for beef cattle, swine and fish, for BRD, SRD, enteric disease
• Danofloxacin, approved for beef cattle for BRD
• Tulathromcin, approved for cattle and swine for BRD, foot rot, IBK, DRK
• Gamithromycin, approved for beef cattle for BRD
• Tildipirosin, approved for cattle for BRD
• Tylavalosin, approved for pigs for ileitis, PPE

Future of antibiotics in food animals
“What we are seeing now with regulatory actions we’ll see in the near future,” Carnevale said. “There is a clear regulatory roadmap. There will be more restrictions on current approvals, limited development of new antimicrobials,  and increasing cost and time for development. He did highlight a need for development of new avian antibiotic products.. “Developing newer technologies will be important as greater restrictions on conventional antibiotics are enforced, Carnevale said.

Carnevale said likely candidates for future antimicrobial approvals based on current FDA policy for food animals would include:

• Antimicrobials with non-human use to minimize resistance
• Prescription-only or VFD antimicrobials but no OTC uses
• Administration via injection to individual animals for less than 6 days, or for selected pens or groups for targeted treatment and limited dosing.

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