FDA Grants Conditional Approval for First Drug to Combat New World Screwworm in Cattle

The U.S. Food and Drug Administration (FDA) has granted conditional approval for the first drug specifically aimed at preventing and treating New World screwworm infestations in cattle. This development offers a new tool for American farmers and ranchers facing this significant animal health threat. The conditionally approved drug, Dectomax-CA1 (doramectin injection) injectable solution, is designed to prevent and treat larval infestations of the New World screwworm and offers protection against reinfestation for up to 21 days.

The conditional approval process signifies that the FDA has determined the drug to be safe and possesses a reasonable expectation of effectiveness. This designation is applied when a drug is intended for serious or life-threatening conditions, addresses an unmet medical need, and where demonstrating full effectiveness would involve complex or challenging studies. Dectomax-CA1 is the first drug to receive this type of approval in the United States for New World screwworm. While the sponsor gathers the necessary data for full approval, cattle producers can now access this treatment immediately.

Dectomax-CA1 contains the same active ingredient, doramectin injection, at the same dosage as Dectomax, a drug already fully approved by the FDA for treating and controlling certain nematode and arthropod parasites in cattle and swine. Because the original approval of Dectomax established adequate safety, manufacturing, and human food safety information, these aspects did not require new data for the conditional approval of Dectomax-CA1.

Cattle producers should be aware of specific withdrawal periods and warnings associated with Dectomax-CA1. The withdrawal period for cattle is 35 days, consistent with Dectomax. Important restrictions to prevent drug residues in meat include its prohibition for use in female dairy cattle aged 20 months or older. Additionally, a withdrawal period has not been established for preruminating calves, and the product should not be used in calves intended for veal processing. Dectomax-CA1 will be available in 250 mL and 500 mL bottles, with product labeling that includes indications for both Dectomax and Dectomax-CA1, although each will have a unique application number.

To mitigate the risk of antiparasitic resistance and maintain the effectiveness of drugs against other parasites, producers and veterinarians are advised to use antiparasitic medications like Dectomax-CA1 only when medically necessary. This includes adhering to product labeling and integrating such treatments into a comprehensive parasite management plan. Zoetis, based in Kalamazoo, Michigan, is the sponsor of Dectomax-CA1.

Article by Mel Anara, based upon information from the U.S. Food and Drug Administration.

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