Elanco Launches Befrena™ (tirnovetmab), New Anti-IL-31 Monoclonal Antibody, a Breakthrough Addition to the $1.3 Billion U.S. Canine Dermatology Market

Elanco (NYSE: ELAN) launched Befrena (tirnovetmab), a new anti-IL-31 monoclonal antibody injection for canine allergic and atopic dermatitis in the $1.3 billion U.S. canine dermatology market.

Rhea-AI Summary

Elanco (NYSE: ELAN) launched Befrena (tirnovetmab), a new anti-IL-31 monoclonal antibody injection for canine allergic and atopic dermatitis in the $1.3 billion U.S. canine dermatology market. The phased U.S. launch begins via an Early Experience Program.

Befrena starts controlling itch within 24 hours, provides 6–8 weeks relief, has no age or weight restrictions, and is administered as an in-clinic injection. Approved by the USDA in December 2025, Befrena makes Elanco the only pet health company with two USDA-approved mAb products.

Positive

• Entry into $1.3 billion U.S. canine dermatology market with Befrena
• Befrena offers 6–8 weeks itch relief and onset within 24 hours
• No age or weight restrictions for Befrena-treated dogs
• USDA approval for Befrena received in December 2025
• Elanco now has two USDA-approved monoclonal antibody products
• Early Experience Program veterinarians report positive clinical outcomes

Negative

• None.

Argus May 18 session

+0.35% close to close Open Argus

Details

News Market Reaction – ELAN

On May 18, the day this news came out, ELAN closed 0.35% above the previous close.

Data tracked by StockTitan Argus for the May 18 session.

Key Figures

Canine dermatology market: $1.3 billion Befrena duration: 6 to 8 weeks Incumbent duration: 4 to 8 weeks +5 more

Canine dermatology market

$1.3 billion

Size of U.S. canine dermatology market mentioned in headline

Befrena duration

6 to 8 weeks

Duration of itch relief for dogs treated with Befrena

Incumbent duration

4 to 8 weeks

Duration range for current market incumbent lokivetmab

Onset of action

24 hours

Time for Befrena to start controlling itch

Befrena approval date

December 2025

USDA approval timing for Befrena

USDA-approved mAbs

2 products

Number of USDA approved monoclonal antibodies Elanco has in pet health

Prevalence of itchy dogs

Nearly 9 in 10 dogs

Owners reporting their dogs as "itchy" in Elanco’s report

Follow-up duration

Two weeks

Zephyr case description: status two weeks after receiving Befrena

Historical Context

5 past events · Latest: May 14

5 events

1. May 14

   Investor conferences update

   24h Move

   -0.7%

   Management announced participation in two upcoming investor conferences.

2. May 06

   Q1 2026 earnings

   24h Move

   +13.9%

   Strong revenue growth, higher EBITDA and EPS, and raised 2026 guidance.

3. Apr 27

   Emergency use authorization

   24h Move

   +0.3%

   FDA and EPA actions enabling use of screwworm treatments in livestock.

4. Apr 27

   Regulatory correction

   24h Move

   +0.3%

   Correction detailing emergency authorizations and timelines for products.

5. Apr 24

   Executive appointment (peer)

   24h Move

   +1.6%

   Former Elanco CFO named CFO at National Veterinary Associates.

24h Move is the share-price change in the day after each event; other market factors may also have contributed.

Key Terms

anti-il-31, monoclonal antibody, mab, canine atopic dermatitis, +2 more

6 terms

anti-il-31 medical

"Phased launch of new anti-IL-31 monoclonal antibody is now underway"

Anti-IL-31 are drugs, usually antibody-based, that block interleukin‑31, a signaling protein that drives itching and skin inflammation. Think of them as targeted roadblocks that stop a chemical messenger causing chronic itch; for investors they matter because success in clinical trials, approvals, and market adoption can create new revenue streams in dermatology and allergy markets and reshape competitive dynamics among drugmakers.

monoclonal antibody medical

"new anti-IL-31 monoclonal antibody (mAb) injection for treatment"

A monoclonal antibody is a laboratory-made protein designed to recognize and attach to a specific target in the body, such as a disease-causing substance or cell. It functions like a highly precise lock-and-key tool, helping to treat or detect illnesses. For investors, companies developing monoclonal antibodies can represent promising opportunities in the healthcare sector, especially as these treatments often address unmet medical needs.

mab medical

"a new anti-IL-31 monoclonal antibody (mAb) injection for treatment"

A mAb (monoclonal antibody) is a lab-made protein designed to recognize and bind a specific target on cells or pathogens, like a custom-made key that fits one lock. Investors care because mAbs are often developed as therapies or diagnostic tools whose clinical trial results, regulatory approvals, production capacity, and patent status can drive significant revenue swings and affect a company’s valuation and risk profile.

canine atopic dermatitis medical

"allergic dermatitis and canine atopic dermatitis with no age or weight"

A chronic allergic skin condition in dogs that causes itching, redness and recurring rashes when their immune system overreacts to common things like pollen, dust mites or mold — think of it as canine eczema. It matters to investors because it drives ongoing veterinary visits and steady demand for treatments, diagnostics and specialty pet-care products, creating predictable market opportunities and potential value from new drugs or devices that reduce symptoms or prevent flare-ups.

cytokine medical

"By neutralizing IL-31, a key cytokine involved in sending itch signals"

Small proteins produced by cells that act as chemical messengers to coordinate immune and inflammatory responses, like text messages or traffic signals telling cells when to activate, calm down, or move. Investors care because cytokines are common drug targets and biomarkers; changes in cytokine activity can determine a therapy’s effectiveness, safety, regulatory approval, and market potential, so trial results or safety signals tied to cytokines often drive stock moves.

usda regulatory

"Elanco received approval of Befrena from the U.S. Department of Agriculture (USDA)"

The United States Department of Agriculture (USDA) is the federal agency that sets food and farming policy, enforces safety and inspection rules, and publishes regular data on crops, livestock and agricultural markets. Its reports and decisions act like a weather forecast for food and farm businesses—shaping crop prices, supply availability, subsidies and trade rules—so investors watch USDA announcements to gauge future commodity prices, company revenues and regulatory risks.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Phased launch of new anti-IL-31 monoclonal antibody is now underway, with product being used by select Early Experience Program veterinarians in clinics today

• Befrena is effective for the treatment of dogs against allergic dermatitis and canine atopic dermatitis with no age or weight restrictions, and lasts 6 to 8 weeks, compared to the 4 to 8 weeks of the current market incumbent, lokivetmab
• Starts controlling itch within 24 hours and is given as an in-clinic injection
• Select Early Experience Program veterinarians are already using Befrena in clinical practice and seeing positive outcomes
• Meet Beaux, Penelope and Zephyr, the first early experience patients to receive Befrena and follow their journeys to itch relief
• Befrena is Elanco's second monoclonal antibody to launch in the U.S. pet health market, joining Trutect™, the first and only approved therapeutic solution to treat canine parvovirus and has been shown to be effective for passive immunity

INDIANAPOLIS, May 18, 2026 /PRNewswire/ -- Elanco Animal Health Incorporated (NYSE: ELAN) today announced the phased launch of Befrena™ (tirnovetmab), a new anti-IL-31 monoclonal antibody (mAb) injection for treatment of canine allergic and atopic dermatitis. The launch comes at a key time, with a longer and more intense allergy season anticipated across the country this year.ⁱ With nearly 2 in 3 itchy dogs experiencing worse itch during allergy seasonⁱⁱ, Befrena expands Elanco's dermatology portfolio by offering a new treatment option that starts controlling allergic itch within 24 hours. By neutralizing IL-31, a key cytokine involved in sending itch signals to the brain, Befrena offers a differentiated 6 to 8 weeks dosing interval, providing veterinarians and pet owners with a new level of convenience and efficacy.

Benefits of Befrena:  

• Offers at least 6 to 8 weeks of itch relief, in contrast to the 4 to 8 weeks of the current market incumbent, lokivetmab
• Starts controlling itch within 24 hours
• Given as an in-clinic injection administered by, or under the supervision of, a licensed veterinarian

Elanco received approval of Befrena from the U.S. Department of Agriculture (USDA) in December 2025, making it the company's second dermatology product, alongside Zenrelia™ (ilunocitinib tablets), to be approved and launched in the past two years.

Elanco is also now the only pet health company with two USDA approved mAb products – Befrena and Trutect. Trutect is the first and only approved therapeutic solution to treat canine parvovirus.

"The commercial launch of Befrena into the $1.3 billion U.S. canine dermatology marketⁱⁱⁱ is another exciting milestone in our innovation journey," said Bobby Modi, Executive Vice President, U.S. Pet Health and Global Digital Transformation. "We are seeing positive results from our Early Experience Program veterinarians who have started using Befrena in their clinics and will continue to increase supply of this new monoclonal antibody, as we scale our bioreactors with the anticipated manufacturing ramp-up."

Make Best Friends Better – Meet the First Dogs Treated with Befrena

Nearly 9 in 10 dogs in the U.S. are "itchy dogs" according to their pet owners, having experienced symptoms of itch at any point throughout the yearⁱⁱ. Data in Elanco's America's Itchy Dogs Report also found that veterinarians say that itchy dog owners wait too long before bringing in their dog, resulting in raw and infected skin and an irritated dog owner who wants their dog to experience relief quickly.ⁱⁱ

As a part of the Befrena Early Experience Program, select veterinarians and veterinary dermatologists have already started using Befrena in their clinics and seen initial improvements in itchy dogs.

Beaux from Austin, TX was the first dog treated with Befrena after experiencing significant hair loss due to his constant itch.

According to Dr. Matt Lane at Liberty Animal Hospital at Beaux's 3-week checkup appointment, "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 and his owner and I are extremely pleased with the results."

Penelope and Zephyr were also treated with Befrena at Gigi's Animal Shelter in Columbus, OH. Both dogs experience seasonal allergies that impact their behavior and quality of life and after discussing with their veterinarian both owners chose Befrena to control their dogs' itch.

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

Zephyr's owner is also a licensed veterinary technician at Gigi's and helped administer Zephyr's injection. You can follow along their journey below.

https://elanco.wistia.com/medias/5nbmg3s2hk

"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 Dr. Tom Lewis, veterinary dermatologist and founder of Dermatology for Animals, a group of veterinary dermatology clinics committed to caring for pets with allergies. "This will become a very important treatment option for many allergic dogs and I am excited to use Befrena in my clinic."*

"I've used Befrena in a few patients so far and while it's still relatively early, I'm very optimistic and excited about what's going to happen with these cases," said Dr. Jason Pieper, veterinary dermatologist and tenured associate professor of dermatology at Iowa State University College of Veterinary Medicine. "I've had several patients respond very well including one unique case that has failed multiple other treatments for atopic dermatitis. And so far, two weeks after receiving Befrena, this dog's doing quite well, it's wonderful."*

Learn more about Befrena and sign up for future news and webinars at www.befrenaforvets.com.

*Drs. Pieper and Lewis are consultants for Elanco.

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.

INDICATIONS
Zenrelia is a prescription medication used to control itching and inflammation associated with skin allergies for dogs over 12 months of age.

IMPORTANT SAFETY INFORMATION
Read the package insert, including the Boxed Warning, before using this drug. For full prescribing information speak with your veterinarian, call 1 888 545 5973 or visit www.elancolabels.com/us/zenrelia.

WARNING: INADEQUATE IMMUNE RESPONSE TO VACCINES. Based on results of the vaccine response study, dogs receiving Zenrelia are at risk of an inadequate immune response to vaccines. Discontinue Zenrelia for at least 28 days to 3 months prior to vaccination and withhold Zenrelia for at least 28 days after vaccination. Dogs should be up to date on vaccinations prior to starting Zenrelia. Do not use in dogs less than 12 months old or dogs with a serious infection. Dogs should be monitored for infections because Zenrelia may increase the chances of developing an infection. Neoplastic conditions (benign and malignant) were observed during clinical studies. The most common side effects were vomiting, diarrhea and tiredness. Zenrelia has not been tested in dogs used for breeding, pregnant, or lactating dogs and has not been evaluated in combination with glucocorticoids, cyclosporine, or other immune suppressive drugs.

Befrena, Zenrelia, Trutect, Elanco and the diagonal bar logo are trademarks of Elanco or its affiliates. © 2026 Elanco or its affiliates

PM-US-26-0849

ⁱ Asthma and Allergy Foundation of America, (2026). 2026 Allergy Capitals. Retrieved from allergycapitals.org.
ⁱⁱ Elanco Animal Health. Data on File. REF-28442
ⁱⁱⁱ Elanco Animal Health. Data on File. REF-29772

Investor Contact: Tiffany Kanaga (765) 740-0314 tiffany.kanaga@elancoah.com
Media Contact: Season Solorio (765) 316-0233 season.solorio@elancoah.com  

View original content to download multimedia:https://www.prnewswire.com/news-releases/elanco-launches-befrena-tirnovetmab-new-anti-il-31-monoclonal-antibody-a-breakthrough-addition-to-the-1-3-billion-us-canine-dermatology-market-302774316.html

SOURCE Elanco Animal Health

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What is Elanco (NYSE: ELAN) Befrena and what conditions does it treat?

Befrena is an anti-IL-31 monoclonal antibody injection for dogs with allergic dermatitis and canine atopic dermatitis. According to Elanco, it targets IL-31, a cytokine involved in itch signaling, to help reduce itching and improve comfort in affected dogs.

How quickly does Befrena (tirnovetmab) control itch in dogs and how long does it last?

Befrena starts controlling allergic itch within 24 hours of injection. According to Elanco, a single dose provides at least 6 to 8 weeks of relief, offering a differentiated dosing interval versus the current market incumbent lokivetmab.

When was Befrena approved and launched in the U.S. by Elanco (ELAN)?

Befrena received USDA approval in December 2025 and is now in a phased U.S. launch. According to Elanco, select veterinarians are already using it through an Early Experience Program, with broader supply expected as bioreactor manufacturing ramps up.

How is Befrena administered to dogs and are there age or weight limits?

Befrena is given as an in-clinic injection by or under a licensed veterinarian’s supervision. According to Elanco, it has no age or weight restrictions, enabling use across a wide range of canine patients with allergic or atopic dermatitis.

What makes Befrena important for the U.S. canine dermatology market and Elanco shareholders?

Befrena adds a new biologic option in the $1.3 billion U.S. canine dermatology market. According to Elanco, it expands the company’s dermatology portfolio and makes Elanco the only pet health company with two USDA-approved monoclonal antibody products.

How are veterinarians and early patients responding to Befrena treatment so far?

Early Experience Program veterinarians report positive outcomes and rapid itch reduction in dogs like Beaux, Penelope and Zephyr. According to Elanco, clinicians observed improvements within 24 hours and multi-week relief, and several dermatologists describe the product as highly safe and effective in early use.