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U.S. Department of Health and Human Services

Animal & Veterinary

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CVM Approves First 4-Way Combination Drug

FDA Veterinarian Newsletter September/October 2004 Volume XIX, No V

The Center for Veterinary Medicine (CVM) recently approved the first four-way drug combination product under the Animal Drug Availability Act of 1996 (ADAA) that eased the requirements for combination -approvals.

Before ADAA, a drug sponsor had to prove the effectiveness of each drug in the combination drug. Under ADAA, the sponsor faces no additional requirements to prove effectiveness of combinations made up of previously approved drugs. The sponsor needs only to show that each drug brings an additional claim to the combination and the drug’s safety is not diminished.

ADAA, which CVM supported, changed several rules concerning animal drugs. It created the system of feed mill licensing, so that feed mills would no longer need separate approved applications for each medica-ted feed. ADAA also allowed CVM to create the category of Veterinary Feed Directive drugs. This category -allows certain drugs to be used in feed under the supervision or on the order of a veterinarian.

ADAA also required FDA to publish a final rule defining “adequate and well-controlled” for field studies. It amended the definition of “substantial evidence” of effectiveness in permitting more flexibility in studies to prove a drug’s effectiveness. It asked FDA to develop a report on changes that would help get drugs for minor species or minor uses approved, and changed the law so that sponsors were entitled to presubmission conferences.

For combination drugs, ADAA “streamlined the process” and -removed certain regulatory hurdles, according to Dr. Dan Benz, an animal scientist with the Ruminant Drugs Team at CVM. He pointed out that one of the drugs in the four-way combination, Optaflexx, was approved just a little over a year before the four-way combination product was approved.

The recently approved four-way combination product is an over-the-counter Type A medicated feed article approved for use in heifers fed in confinement for slaughter. The product is made up of four previously approved products—Optaflexx (ractopamine hydrochloride), Rumensin (monensin sodium), Tylan (tylosin phosphate) and MGA (melengestrol acetate). The sponsor is Elanco Animal Health.

The four-way combination product is approved for increased rate of weight gain, improved feed efficiency increased carcass leanness, the prevention and control of coccidiosis due to Eimeria bovis and E. zuernii, reduction of incidence of liver abscesses caused by Fusobacterium necrophorum and Actinomyces (Corynebacterium) pyogenes and suppression of estrus.