First drug for screwworm treatment, prevention receives conditional approval
The Food and Drug Administration (FDA) has conditionally approved the first drug for the prevention and treatment of New World screwworm (NWS) in cattle.
The FDA granted conditional approval to Dectomax-CA1, a doramectin injection, for treating infestations caused by larvae of Cochliomyia hominivorax, and prevention of reinfestation for 21 days in cattle, according to a September 30 press release.
"We understand the urgency with which America’s farmers and ranchers are asking for tools to fight New World screwworm," FDA Commissioner Martin Makary said in the press release.
Dectomax-CA1 is an over-the-counter injectable solution that is available in 250 mL and 500 mL multi-dose vials. The dosage is 1 mL (10 mg doramectin) per 110 lbs of body weight (200 mcg/kg) administered by subcutaneous or intramuscular injection in the neck region.
Dectomax-CA1 contains the same active ingredient, doramectin, at the same dose as Dectomax. Dectomax is fully approved for treatment and control of certain nematode and arthropod parasites in cattle and swine. The withdrawal period for cattle treated with Dectomax-CA1 is 35 days, the same as for Dectomax.
To prevent drug residues, it is not for use in dairy cattle aged 20 months or older or veal calves.
Timothy Schell, acting director of the FDA Center for Veterinary Medicine (CVM), said the FDA has determined the drug is safe with "a reasonable expectation of effectiveness," and will be available immediately while drug sponsor Zoetis collects data for a full approval.
"The FDA will continue to expedite review of animal drugs to help the U.S. fight this devastating threat to our nation's livestock and the livelihoods of the farmers and ranchers who care for them," he said.
The conditional approval comes after a human case of travel-associated NWS was reported in August, and in late September, the flesh-eating parasite was detected fewer than 70 miles south of the U.S.-Mexico border, prompting calls for veterinary vigilance.
"We continue to work tirelessly to complete review of other NWS products to protect multiple animal species in the U.S.," Makary said.
Notice of the conditional approval is posted on the FDA’s website. The FDA CVM has also provided information on other drugs veterinarians may consider using extralabel for cattle and other species, including dogs and cats.
The Food and Drug Administration Center for Veterinary Medicine offers information on New World screwworm (NWS) for veterinarians.
The AVMA also provides a resource page on NWS, including information about its changing geographic distribution, how NWS infestation is treated, and ways to prevent its spread.