Elanco Announces Expansion of Credelio Quattro™ (lotilaner, moxidectin, praziquantel, and pyrantel chewable tablets) and Credelio™ (lotilaner) Labels, Offering Protection Against Lyme Disease and an Emerging Tick Species

Rhea-AI Summary

Elanco (NYSE: ELAN) announced U.S. label expansions for Credelio Quattro and Credelio on Oct 27, 2025, adding prevention of Lyme disease via killing black-legged ticks (Ixodes scapularis) and treatment/control of the invasive longhorned tick (Haemaphysalis longicornis).

The labels reflect clinical evidence, including a peer-reviewed study showing 100% efficacy against longhorned tick at 48 hours and data supporting lotilaner’s rapid tick kill versus competing products. The announcements cite >422,000 canine Lyme cases recorded year-to-date and note longhorned ticks have been detected in 22 states.

Positive

• U.S. label expansion to include Lyme prevention
• Label adds treatment/control of longhorned tick
• Peer-reviewed study: 100% efficacy vs longhorned tick at 48 hours
• Cites >422,000 canine Lyme cases year-to-date
• Lotilaner reported to kill lone star tick faster than competitors

Negative

• None.

Insights

Regulatory and Commercial Analyst

FDA label expansions for Credelio Quattro and Credelio broaden tick-borne disease claims and coverage against an invasive tick species.

Both products now include prevention of Lyme disease via killing black-legged ticks and treatment/control of the longhorned tick, with the announcement dated Oct. 27, 2025. The expanded claims explicitly link lotilaner to killing vectors of Lyme disease and cite peer-reviewed data showing 100% efficacy versus the longhorned tick at 48 hours and maintained for a month. The release also cites more than 422,000 canine Lyme cases year-to-date and the longhorned tick’s presence in 22 states as supporting context.

This change directly affects regulatory positioning and product differentiation in the canine parasiticide market by adding disease-prevention language and an evidence-backed claim against an emerging invasive species. Key dependencies include label implementation logistics, veterinarian adoption, and how payers or clinics incorporate the new claims into prescribing guidance. Watch for updated product literature, timing of roll-out to clinics, any regulatory follow-ups that clarify the exact wording of the Lyme prevention claim, and real-world uptake over the next 1–2 seasons.

•  FDA approves expanded Credelio Quattro and Credelio labels to include prevention of Lyme disease as a result of killing black-legged ticks (lxodes scapularis) and protection against the longhorned tick (Haemaphysalis longicornis), which is rapidly spreading, now reaching 22 states.ⁱ
•  The Companion Animal and Parasite Council tracker shows more than 422,000 cases of Lyme disease in dogs so far this year,ⁱⁱ surpassing the total number of annual cases seen in all of 2019.ⁱⁱⁱ
•  Elanco continues to go beyond for veterinarians and pet owners, providing even more comprehensive protection against some of the most concerning ticks.

INDIANAPOLIS, Ind., Oct. 27, 2025 /PRNewswire/ -- Elanco Animal Health Incorporated (NYSE: ELAN) today announced label expansions for two of its leading canine prescription parasiticides, Credelio Quattro (lotilaner, moxidectin, praziquantel, and pyrantel chewable tablets) and Credelio (lotilaner), with both product labels updated to include:  

• Prevention of Lyme disease as a direct result of killing black-legged ticks (lxodes scapularis)
• Treatment and control of longhorned tick (Haemaphysalis longicornis) infestations

Given the rising threat of ticks and tick-borne disease, this expanded protection for dogs is timely. The Companion Animal and Parasite Council tracker shows more than 422,000 cases of Lyme disease in dogs so far this year,ⁱⁱ surpassing the total number of annual cases seen in all of 2019.ⁱⁱⁱ On the human side, the CDC reported that this May had the highest level of tick bites seen in human emergency room visits since 2019.^iv  Pets and people can encounter ticks in common areas like the backyard or simply walking around the neighborhood, so it is important for dogs to be protected with a flea and tick treatment year-round.

"This label expansion is a testament to Elanco's unwavering commitment to innovation and scientific excellence," said Dr. Ellen de Brabander, Executive Vice President, Innovation and Regulatory Affairs, at Elanco. "Our research and development teams are constantly working to anticipate and address emerging threats, ensuring and demonstrating that Credelio Quattro and Credelio continue to provide leading-edge protection for dogs against a complex and evolving parasitic landscape."

Lotilaner vs. Lyme Disease
The active ingredient lotilaner in both Credelio Quattro and Credelio has been found highly effective for killing the black-legged vector ticks (lxodes scapularis), which are the most common spreaders of Lyme disease.^v Both labels in the U.S. now include a claim for prevention of Lyme disease in dogs as a direct result of killing black-legged ticks.

With more than 422,000 cases of Lyme disease in dogs already recorded this year, northeast states including New York, Maine, New Hampshire, Vermont, Pennsylvania and Connecticut are a few of the states with the most positive cases.ⁱⁱ  And it's not just cases of Lyme disease in dogs that are on the rise. A 2021 estimate suggests that each year, approximately 476,000 Americans are diagnosed and treated for Lyme disease.^vi

"With this label expansion, pet owners and veterinarians now have more options to protect dogs from Lyme disease," said Dr. Casey Locklear, veterinarian and parasiticide lead for Elanco Animal Health. "With higher positive cases of canine Lyme disease already confirmed this year by the CAPC,^iv pet owners should ask their veterinarian for parasite protection that includes protection against Lyme disease, like Credelio Quattro or Credelio."   

Lotilaner vs. Longhorned Tick
The longhorned tick is an invasive tick species that is rapidly spreading and is now in 22 states around the country,ⁱ posing a significant threat to animal and human health. The ticks' ability to transmit canine pathogens, like Ehrlichia and Babesia species also highlights its potential risk for dogs as the population continues to spread across the country.^vii

"The unique biology of the longhorned tick is what makes it a potential public health challenge," said Dr. Locklear. "They can establish populations of thousands from a single female because they have the ability to reproduce without mates."

In a recent peer-reviewed and published study in Parasites and Vectors, both Credelio Quattro and Credelio demonstrated 100% efficacy against the longhorned tick at 48 hours after infestation and continuing throughout the month.^viii

Lotilaner vs. Lone Star Tick 
While both Credelio Quattro and Credelio were already approved to protect dogs from the lone star tick (Amblyomma americanum), the rise in tick infestations across the country reinforces the need for effective parasite control. This aggressive and expanding tick species is found across the country, is one of the hardest to kill, and is best known for its association with alpha-gal syndrome (red meat allergy) in humans. It can also transmit dangerous disease-causing pathogens to dogs.^iv The active ingredient lotilaner in both Credelio Quattro and Credelio kills the lone star tick faster* than sarolaner in Simparica Trio^® and afoxolaner in NexGard^®, protecting dogs against this pathogen-carrying tick. 

"It is critical that veterinarians talk with pet owners about year-round parasite protection," said Dr. Kathryn Reif, Bailey-Goodwin Endowed Associate Professor in Parasitology at Auburn University. "The rapid and sustained speed of tick kill of Credelio Quattro and Credelio helps protect dogs against pathogen-carrying ticks which can result in dangerous diseases."

"This expanded label for Credelio Quattro and Credelio is exciting for pet owners and veterinarians alike," said Bobby Modi, Executive Vice President, U.S. Pet Health and Digital Transformation at Elanco. "Our expanded label demonstrates even more comprehensive protection against some of the most concerning ticks, going beyond for both pet owners and veterinarians and helping dogs live healthier, happier, more active lives."

To learn more about Credelio Quattro and Credelio and how they protect against emerging parasite threats, please visit QuattroDogVet.com and https://my.elanco.com/us/credelio-dog.

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.

CREDELIO 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.

CREDELIO QUATTRO INDICATIONS
Credelio Quattro is indicated for the prevention of heartworm disease and the treatment and control of roundworm, hookworm, and tapeworm infections. Credelio Quattro kills adult fleas and is indicated for the treatment and prevention of flea infestations and the treatment and control of tick infestations for 1 month in dogs and puppies 8 weeks of age and older and weighing 3.3 pounds or greater. Credelio Quattro is indicated for the prevention of Lyme disease infections as a direct result of killing black-legged ticks.

CREDELIO QUATTRO IMPORTANT SAFETY INFORMATION
Lotilaner, an ingredient in Credelio Quattro, belongs to the isoxazoline class and has been associated with neurologic adverse reactions like tremors, incoordination, and seizures even in dogs without a history of seizures. Use with caution in dogs with a history of seizures or neurologic disorders. Dogs should be tested for existing heartworm infections before Credelio Quattro administration as it is not effective against adult heartworms. The safe use in breeding, pregnant, or lactating dogs has not been evaluated. The most frequently reported adverse reactions in clinical trials were vomiting and diarrhea. For complete safety information, please see the Credelio Quattro product label or ask your veterinarian.

NexGard is a registered trademark of Boehringer Ingelheim Animal Health USA Inc. Simparica TRIO is a registered trademark of Zoetis Services LLC.

Credelio, Credelio Quattro, Elanco and the diagonal bar logo are trademarks of Elanco or its affiliates. Other company and product names are trademarks of their respective owners. © 2025 Elanco or its affiliates

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ⁱ Triltsch, O. (2025, August 28). Tiny invaders: The rise of the Asian longhorned tick. Michigan United Conservation Clubs: Join Us Today! https://www.mucc.org/tiny-invaders-the-rise-of-the-asian-longhorned-tick

ⁱⁱ Companion Animal Parasite Council. Parasite Prevalence Maps – Lyme Disease in Dogs, United States, 2025 (All Year). Accessed September 24, 2025. https://capcvet.org/maps/#/2025/all-year/lyme-disease/dog/united-states

ⁱⁱⁱ Companion Animal Parasite Council. Parasite Prevalence Maps – Lyme Disease in Dogs, United States, 2019 (All Year). Accessed September 24, 2025. https://capcvet.org/maps/#/2019/all-year/lyme-disease/dog/united-states

^iv Centers for Disease Control and Prevention. (n.d.). Where Ticks Live. Centers for Disease Control and Prevention. Retrieved August 8, 2024, from https://www.cdc.gov/ticks/about/where-ticks-live.html 

^v Murphy M, Garcia R, Karadzovska D, Cavalleri D, Snyder D, Seewald W, Real T, Drake J, Wiseman S, Nanchen S. Laboratory evaluations of the immediate and sustained efficacy of lotilaner (Credelio™) against four common species of ticks affecting dogs in North America. Parasit Vectors. 2017 Nov 1;10(1):523. doi: 10.1186/s13071-017-2476-y. PMID: 29089057; PMCID: PMC5664823.

^vi Kugeler, K. J., Schwartz, A. M., Delorey, M. J., Mead, P. S., & Hinckley, A. F. (2021). Estimating the Frequency of Lyme Disease Diagnoses, United States, 2010–2018. Emerging Infectious Diseases, 27(2), 616-619. https://doi.org/10.3201/eid2702.202731.

^vii Dye-Braumuller KC, Gual-Gonzalez L, Abiodun T, Rustin LP, Evans CL, Meyer MM, Zellars K, Neault MJ, Nolan MS. Invasive Haemaphysalis longicornis (Acari: Ixodidae) investigation in South Carolina: new records of establishment, pathogen prevalence, and blood meal analyses. J Med Entomol. 2023 Nov 14;60(6):1398-1405. doi: 10.1093/jme/tjad119. PMID: 37658780; PMCID: PMC10645392.

^viii Wiseman, S., Savadelis, M.D., Maree, R. et al. Efficacy of Credelio Quattro^™ (lotilaner, moxidectin, pyrantel, praziquantel) and Credelio^™ (lotilaner) against longhorned tick, Haemaphysalis longicornis,-induced infestations on dogs. Parasites Vectors 18, 344 (2025). https://doi.org/10.1186/s13071-025-06965-y

* Based on time to statistical significance vs control in a head-to-head study. The study compared Credelio™ (lotilaner)—not Credelio Quattro™, which contains lotilaner as well as moxidectin, praziquantel, and pyrantel—to the active ingredients in Simparica Trio™ (sarolaner, moxidectin, and pyrantel) and NexGard™ (afoxolaner)

Investor Contact: Tiffany Kanaga (765) 740-0314 tiffany.kanaga@elancoah.com

Media Contact: Season Solorio (765) 316-0233 season.solorio@elancoah.com 

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SOURCE Elanco Animal Health

FAQ

What did Elanco (ELAN) announce about Credelio and Credelio Quattro on October 27, 2025?

Elanco announced U.S. label expansions adding Lyme disease prevention via killing black-legged ticks and treatment/control of longhorned tick.

How do the new Credelio labels claim to prevent Lyme disease in dogs (ELAN)?

The labels state prevention of Lyme disease is a direct result of killing black-legged ticks (Ixodes scapularis).

What evidence supports Credelio Quattro and Credelio protection against the longhorned tick?

A peer-reviewed study reported 100% efficacy at 48 hours against Haemaphysalis longicornis sustained through the month.

How widespread is the longhorned tick according to Elanco's Oct 27, 2025 announcement?

Elanco noted the longhorned tick is now reported in 22 states.

What canine Lyme disease data did Elanco cite in the label expansion news?

Elanco cited the Companion Animal and Parasite Council tracker showing more than 422,000 canine Lyme cases so far this year.

Will the Credelio label expansions change veterinarian recommendations for parasite protection?

Elanco and its veterinarians say the expanded labels give pet owners and vets more options to choose products that include Lyme protection, such as Credelio Quattro or Credelio.