The US Food and Drug Administration (FDA) announced that it was looking for projects to set time limits for a selection of medically important antimicrobial drugs on Monday [April 1].
The work is part of the ongoing implementation of Guidance for Industry 213, which took effect in January 2017, and established that all medically important antimicrobials fed or given to livestock in water have to be prescribed by a veterinarian, the FDA said.
All new animal drugs also have a defined period of use, however, some older products did not, the agency added.
The duration of use still needs to be established for some antimicrobials because no time limit was set when they were initially approved, an agency spokesperson said.
“The new animal drug applications with undefined regimens on product labeling were originally approved long ago, and the information used to support approval did not establish a specifically defined duration of use or minimum duration of use when effectiveness was evaluated,” she told FeedNavigator.
The agency will collect applications for studies designed to help “target and define durations of use” for a selection of antimicrobial drugs through June 3. “The number of awards is contingent upon FDA funding availability and the number of suitable applications,” the FDA added.
In September 2020, the FDA plans to release a draft strategy or draft guidance to explain “how to establish defined duration of use for the affected applications identified,” the agency said. “We expect this draft guidance will outline a proposed process, including time periods, sponsors can follow to revise the approved conditions of use accordingly.”
Addressing antimicrobial resistance
The goal of conducting the research projects will be to establish public data, which can be used by sponsors of select antimicrobial drugs used in livestock feed to update recommended “dosage regimes” and address when and for how long a specific drug may be fed, the FDA said.
A “key objective” of the FDA is improving the use of medically important antimicrobials, said the spokesperson.
“Using a dosage strategy that maximizes drug effectiveness, minimizes target animal toxicity, and has an appropriately targeted and defined duration of use,” is intended to reduce the development of bacteria that are resistant to antimicrobial drugs used in human medical care.
“Establishing defined durations of use for currently approved therapeutics will support FDA's efforts to foster stewardship of medically important antimicrobial drugs in food-producing animals and help preserve the effectiveness of these antimicrobials in animal and human medicine,” she said.
“To help with establishing more targeted durations of use for the list of affected products, FDA is seeking substantial evidence of effectiveness, meaning evidence consisting of one or more adequate and well-controlled studies demonstrating that the new animal drug is effective under the conditions of use stated in the approved labeling,” the spokesperson said. “For therapeutic indications, this evidence should be established at the lowest approved dose level (i.e., dose and regimen duration).”
Application process details
The fiscal year 2019 request for research projects is being funded through the FDA’s Center for Veterinary Medicine (CVM). Up to $1.5m has been set aside to support research projects and the process does not require cost sharing.
Multiple organizations have the ability to apply for research funding including public, private and state-based colleges or universities, nonprofits, some for-profit organizations, and some non-federal government agencies.
Research projects can receive up to $250,000 per individual awardee, the FDA said. However, depending on resource availability and the number of projects selected, it is possible that some researchers will be able to apply for a second year of funding in 2020 of up to $250,000.
The project is focused on the use of select antimicrobial drugs with major food-producing species including cattle, turkeys, swine and chickens, the spokesperson said.
Some of the antimicrobials of interest to the FDA include sulfaquinoxaline, oxytetracycline, tylosin, chlortetracycline and virginiamycin in their use as pioneer Type A medicated articles. The full list covers a range of antimicrobials and applications.