Elanco Launches Befrena, a New Anti-IL-31 Monoclonal Antibody for Canine Dermatology

Elanco (NYSE: ELAN) announced the phased U.S. launch of Befrena (tirnovetmab), a new anti-IL-31 monoclonal antibody injection for the treatment of canine allergic and atopic dermatitis.

The launch comes as veterinarians anticipate a longer and more intense allergy season across the United States. According to Elanco data, nearly two-thirds of itchy dogs experience worsening symptoms during allergy season.

By neutralizing IL-31 — a key cytokine involved in itch signaling — Befrena is designed to rapidly control pruritus while offering an extended dosing interval of 6 to 8 weeks. Elanco says the therapy begins controlling itch within 24 hours.

Key Features of Befrena

• Provides 6–8 weeks of itch relief

• Starts controlling itch within 24 hours

• Administered as an in-clinic injection by or under the supervision of a licensed veterinarian

• Targets IL-31, a major mediator of itch signaling in dogs

The U.S. Department of Agriculture approved Befrena in December 2025, making it Elanco’s second dermatology product launched in the past two years alongside Zenrelia (ilunocitinib tablets).

Elanco also noted it is now the only pet health company with two USDA-approved monoclonal antibody products:

• Befrena

• Trutect, indicated for canine parvovirus treatment

“The commercial launch of Befrena into the $1.3 billion U.S. canine dermatology market is another exciting milestone in our innovation journey,” said Bobby Modi, Executive Vice President, U.S. Pet Health and Global Digital Transformation at Elanco.

According to Modi, veterinarians participating in Elanco’s Early Experience Program have reported positive early results as the company continues scaling manufacturing capacity.

Early Clinical Experience

Veterinarians involved in the Early Experience Program have already begun using Befrena in practice settings.

One of the first dogs treated was Beaux, a 6-year-old Yorkshire Terrier from Austin, Texas, who had significant hair loss associated with chronic itching.

According to Dr. Matt Lane of Liberty Animal Hospital:

“Beaux is doing amazing, and his owner is excited to see his hair growing back. He stopped itching within 24 hours of receiving the injection.”

Additional early-use cases included Penelope and Zephyr at Gigi’s Animal Shelter in Columbus, Ohio, where both dogs were treated for seasonal allergic dermatitis.

“We want to get these dogs relief and make sure they have the most comfortable experience possible, and I think Befrena shows real promise for that,” said Meghan Herron, Senior Director of Behavior, Research, and Education at Gigi’s.

Veterinary dermatologists also shared positive preliminary impressions.

“I have been involved with two clinical trials and the Early Experience Program, which has shown Befrena to be a highly safe and effective product,” said Tom Lewis, founder of Dermatology for Animals.

Jason Pieper, associate professor of dermatology at Iowa State University College of Veterinary Medicine, added that several difficult atopic dermatitis cases have responded well during early use.

About Canine Allergic Dermatitis

Canine allergic and atopic dermatitis are among the most common reasons dogs visit veterinarians. Chronic itch can significantly impact quality of life for both dogs and owners and may lead to:

• Secondary skin infections

• Hair loss

• Excoriations

• Behavioral stress

• Chronic inflammation

Targeted biologic therapies such as anti-IL-31 monoclonal antibodies have become increasingly important alternatives to traditional long-term immunosuppressive therapy.

Safety Information

Zenrelia carries a boxed warning regarding inadequate immune response to vaccines. Dogs should be appropriately vaccinated before initiating therapy, and clinicians should monitor for infections during treatment.

The most commonly reported adverse effects include:

• Vomiting

• Diarrhea

• Lethargy

Zenrelia has not been evaluated in breeding, pregnant, or lactating dogs.