Elanco's Credelio™ CAT (lotilaner) Receives First FDA Emergency Use Authorization (EUA) for Treatment of New World Screwworm (NWS) in Cats

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Nov 21, 2025, 13:35 ET

EUA to Treat Cats for NWS Issued Prior to Fly Being Detected in the U.S.; Action Prepares Veterinarians and Pet Owners with Treatment Options

First U.S. Food and Drug Administration Emergency Use Authorization (EUA) granted for New World screwworm in cats, reinforcing Elanco's leadership in feline innovation
Action reinforces the FDA's commitment to act swiftly against emerging animal health threats
Scientific studies showed Credelio CAT may be effective in treating New World screwworm in cats^i,ii
Preventing open wounds through effective flea and tick control is critical in protecting pets from NWS

INDIANAPOLIS, Nov. 21, 2025 /PRNewswire/ -- Elanco Animal Health Incorporated (NYSE: ELAN) today announced it has received Emergency Use Authorization (EUA) from the U.S. Food and Drug Administration (FDA) for Credelio™ CAT (lotilaner) to treat New World screwworm (NWS) infestations in cats. This authorization represents the first EUA granted by the FDA for New World screwworm treatment in felines.

With confirmed cases of New World screwworm detected as close as 70 miles south of the U.S.-Mexico border,ⁱⁱⁱ this EUA ensures veterinarians and pet owners have a ready-now treatment option for cats and kittens should the fly enter the U.S.

"The FDA's swift and thorough evaluation of the scientific evidence showing Credelio CAT's potential effectiveness against New World screwworm in cats is greatly appreciated," said Dr. Ellen de Brabander, Executive Vice President of Innovation and Regulatory Affairs at Elanco. "As a leader in feline health, Elanco is committed to ensuring cats receive complementary innovative solutions to those available to dogs. This historic EUA equips veterinarians and cat owners with a treatment solution and provides reassurance that they're prepared to act quickly if New World screwworm crosses into the U.S."

Elanco's commitment to feline innovation addresses an important gap in companion animal care. Cats have historically had fewer products and treatment options available compared to dogs, and research shows this disparity extends to veterinary visits—with over 90% of dog owners taking their pets to the veterinarian compared to only 40% of cat owners.^iv This EUA ensures that cats have a treatment option on par with their canine counterparts when facing this emerging health threat.

The Emergency Use Authorization was based on research evaluating the efficacy of Credelio CAT against Old World screwworm in cats as well as the efficacy of Credelio against New World screwworm in dogs.

Elanco's Credelio franchise has made significant strides in animal health. Last month, Credelio™ (lotilaner) received the first-ever FDA Emergency Use Authorization for treating NWS in dogs, which is the first time ever that the FDA has issued an EUA for an animal drug. Now, with this EUA for Credelio CAT, the franchise demonstrates its comprehensive approach for providing solutions for both dogs and cats for this emerging threat.

Before New World screwworm reaches the United States, veterinarians and pet owners can take proactive steps to prevent wounds that can create ideal conditions for New World screwworm infection. New World screwworm infestations begin when a female New World screwworm fly lays eggs on open wounds or other parts of the body in live, otherwise healthy, warm-blooded animals. According to the Centers for Disease Control, wounds as small as a tick bite may attract a female fly to feed and lay her eggs. One female can lay 200 – 300 eggs at a time and may lay up to 3,000 eggs during her 10- to 30-day lifespan.^v Unlike most fly species whose larvae may feed on dead and decaying tissue, New World screwworm larvae burrow into the flesh of living animals, causing severe tissue damage and even death if left untreated.

The U.S. Animal Plant Health and Inspection Service (APHIS) recommends that one way to prevent New World screwworm infestations is to protect pets and livestock from other wound-causing parasites such as flies and ticks.^vi

"Given New World screwworm's aggressive and invasive nature, any minor wounds from grooming, scratching, or outdoor activities can serve as an entry point for these parasites," said Dr. Casey Locklear, Texas-based veterinarian and parasiticide lead at Elanco. "It's essential to prevent or quickly address any wounds to keep cats safe from New World screwworm. Year-round flea and tick protection, like Credelio CAT, helps minimize self-inflicted scratching that could create vulnerable sites."

Learn more about Credelio CAT here.
To learn more about NWS, the following resources are available:

ABOUT ELANCO
Elanco Animal Health Incorporated (NYSE: ELAN) is a global leader in animal health dedicated to innovating and delivering products and services to prevent and treat disease in farm animals and pets, creating value for farmers, pet owners, veterinarians, stakeholders and society as a whole. With 70 years of animal health heritage, we are committed to breaking boundaries and going beyond to help our customers improve the health of animals in their care, while also making a meaningful impact on our local and global communities. At Elanco, we are driven by our vision of Food and Companionship Enriching Life and our purpose – all to Go Beyond for Animals, Customers, Society and Our People. Learn more at www.elanco.com.

Emergency Use Authorization for Credelio CAT (lotilaner) for New World Screwworm (NWS)
The U.S. Food and Drug Administration (FDA) has issued an Emergency Use Authorization (EUA) for the emergency use of the approved product Credelio CAT (lotilaner) for the treatment of infestations caused by NWS (Cochliomyia hominivorax) larvae (myiasis) in cats and kittens. Credelio CAT is not approved for this use.

Credelio CAT is approved for other uses.

For additional information on the EUA, please refer to the Credelio Cat NWS Fact Sheet.

Limitations of Authorized Use
Credelio CAT (lotilaner) is authorized for this use only for the duration of the declaration that circumstances exist justifying the authorization of the emergency use of Credelio CAT (lotilaner) under section 564(b)(1) of the Federal Food, Drug, and Cosmetic Act (FD&C Act), 21 U.S.C. § 360bbb-3(b)(1), unless the authorization is terminated or revoked sooner.

CREDELIO CAT APPROVED INDICATIONS
Credelio CAT kills adult fleas and is indicated for the treatment and prevention of flea infestations for one month in cats and kittens 8 weeks of age and older and weighing 2 pounds or greater.

Credelio CAT is also indicated for treatment and control of black-legged tick infestations for one month in cats and kittens 6 months of age and older and weighing 2 pounds or greater.

CREDELIO CAT IMPORTANT SAFETY INFORMATION
Lotilaner is a member of the isoxazoline class of drugs. This class has been associated with neurologic adverse reactions including tremors, incoordination and seizures. Neurologic adverse reactions have been reported in cats receiving isoxazoline class drugs, even in cats without a history of neurologic disorders. Use with caution in cats with a history of neurologic disorders. The safety of Credelio CAT has not been established in breeding, pregnant and lactating cats. The effectiveness of Credelio CAT against black-legged ticks in kittens less than 6 months of age has not been evaluated. The most frequently reported adverse reactions are weight loss, rapid breathing and vomiting. For complete safety information, please see Credelio CAT product label or ask your veterinarian.

Emergency Use Authorization for Credelio (lotilaner) for New World screwworm (NWS)

The U.S. Food and Drug Administration (FDA) has issued an Emergency Use Authorization (EUA) for the emergency use of the approved product Credelio (lotilaner) for the treatment of infestations caused by NWS (Cochliomyia hominivorax) larvae (myiasis) in dogs and puppies. However, Credelio is not approved for this use.

Credelio is approved for other uses.

For additional information on the EUA, please refer to the Credelio NWS Fact Sheet.

Limitations of Authorized Use

Credelio (lotilaner) is authorized only for the duration of the declaration that circumstances exist justifying the authorization of the emergency use of Credelio (lotilaner) under section 564(b)(1) of the Federal Food, Drug, and Cosmetic Act (FD&C Act), 21 U.S.C. § 360bbb-3(b)(1), unless the authorization is terminated or revoked sooner.

CREDELIO APPROVED INDICATIONS
Credelio kills adult fleas and is indicated for the treatment and prevention of flea infestations and treatment and control of tick infestations (lone star tick, American dog tick, black-legged tick, brown dog tick, and longhorned tick) for one month in dogs and puppies 8 weeks and older and 4.4 pounds or greater. Credelio is indicated for the prevention of Lyme disease infections as a direct result of killing black-legged ticks.

CREDELIO IMPORTANT SAFETY INFORMATION
Lotilaner is a member of the isoxazoline class of drugs. This class has been associated with neurologic adverse reactions including tremors, incoordination, and seizures. Seizures have been reported in dogs receiving this class of drugs, even in dogs without a history of seizures. Use with caution in dogs with a history of seizures or neurologic disorders. The safe use of Credelio in breeding, pregnant or lactating dogs has not been evaluated. The most frequently reported adverse reactions are weight loss, elevated blood urea nitrogen, increased urination, and diarrhea. For complete safety information, please see Credelio product label or ask your veterinarian.

PM-US-25-2228

ⁱ Han, HS, Yasmin, L (2020). Chrysomya bezziana (Diptera: Calliphoridae) infestation in two Malaysian cats treated with oral lotilaner. Vet Dermatol, 31:335-e87
ⁱⁱ do Vale, T.L., Costa, A.R., Miranda, L.M. et al. Efficacy of lotilaner against myiasis caused by Cochliomyia hominivorax (Diptera: Calliphoridae) in naturally infested dogs. Parasites Vectors 16, 86 (2023). https://doi.org/10.1186/s13071-023-05661-zⁱⁱⁱ Mexico Confirms Case of New World Screwworm in Nuevo Leon | Animal and Plant Health Inspection Service
^iv Familiarity and Use of Veterinary Services by US Resident Dog and Cat Owners - PMC
^v About New World Screwworm Myiasis | Myiasis | CDC
^vi APHIS, New World Screwworm