Zoetis Receives European Commission Marketing Authorization for Portela® (relfovetmab) to Alleviate Pain Associated with Osteoarthritis in Cats
Zoetis Inc. today announced that the European Commission has granted the company marketing authorization for Portela® (relfovetmab), making it the first monoclonal antibody (mAb) therapy with a three-month dosing interval approved for the alleviation of pain associated with osteoarthritis (OA) in cats.
Designed to provide three months of OA pain relief with a single injection, Portela targets anti-nerve growth factor (NGF), which is a key mediator of OA pain and inflammation. In September of this year, the Committee for Veterinary Medicinal Products (CVMP) recommended granting marketing authorization based on a positive benefit-risk balance of the safety and efficacy data submitted. In a nine-month field trial in Europe, Portela demonstrated effectiveness in alleviating OA pain and was found to be well tolerated, including by cats identified with kidney disease at IRIS stage 1, 2 or 31.
"The European Commission's marketing authorization for Portela marks a pivotal advancement in feline pain management," said Rob Polzer, Ph.D., Executive Vice President and President, Research and Development at Zoetis. "Portela's long-acting antibody properties and its unique binding site to NGF now provide veterinarians and cat owners across the European Union with another innovative, approved option to manage osteoarthritis-related pain. This milestone reflects our continued commitment to advancing innovative therapies that enhance the health and well-being of companion animals."
OA as a Significant Unmet Medical Need
Osteoarthritis (OA) is a common, chronic and progressive joint disease characterized by the inflammation and breakdown of joints, leading to pain and mobility issues. Although the disease cannot be cured, much can be done to control the associated pain and improve quality of life. Though up to 40% of all cats have clinical signs of OA2, 3, these signs are often overlooked by pet owners, and as a result only 18% of affected cats are diagnosed with OA pain by veterinary professionals4. Identifying and treating OA pain is important because chronic pain has a negative impact on many aspects of a cat's health. In addition to gait and movement, chronic pain impacts sleep, relationships, and cognition5. Portela now provides a convenient, long-acting therapy to reduce OA pain - particularly beneficial for cats that are difficult to medicate regularly.
"Osteoarthritis in cats is often underestimated because they're so good at hiding pain. Behavioral changes are frequently seen as ‘just getting older' when they may in fact be signs of long-term discomfort. New therapies that provide lasting pain relief without daily administration are a real step forward - for cats, their owners, and veterinarians," said Dr. Marieke Knies, Dipl. ECVIM, internal medicine specialist in the Netherlands.
Building on a Legacy of Innovation
Portela expands the company's OA pain franchise and joins Solensia® (frunevetmab) – an anti-NGF monoclonal antibody indicated for monthly alleviation of OA pain in cats. Approved in more than 40 countries, Solensia has been demonstrated in clinical trials, as well as in over four years of real-world use by veterinarians, to relieve pain and thereby enhance quality of life for cats with OA pain. As with all medicines, there are potential side effects. For Solensia, the most common (may affect up to 1 in 10 cats) are hair loss, dermatitis and itching; rare (may affect up to 1 in 1,000 cats) side effects are injection site reactions and skin lesions; and, very rare (may affect up to 1 in 10,000 cats) side effects are anaphylaxis. For Portela, based on clinical trials, the most common side effect (may affect >1 cat / 10 cats treated) is immediate pain upon injection, followed by dermatitis (may affect up to 1 in 10 cats); uncommon side effects (may affect up to 10 in 1,000 cats) include pruritus, skin scabs, injection site swelling and injection site hair loss.
"Portela is a new, science-driven therapy designed to support long-term comfort and mobility for cats—with the added benefit that pet owners only need to bring their cats in for an injection once every three months. This is a testament to the value we place at Zoetis on meaningful innovation in feline medicine, solving for the unmet needs of our patients and their families," said Richard Goldstein, DVM, DACVIM, DECVIM-CA, Global Chief Medical Officer and Head of Medical Affairs at Zoetis. "We look forward to providing veterinarians with another innovative tool, adding to our wide feline portfolio, to help them improve the quality of life for the cats in their care."
Zoetis anticipates making Portela commercially available in the European Union in 2026.
About Zoetis
As the world's leading animal health company, Zoetis is driven by a singular purpose: to nurture our world and humankind by advancing care for animals. After innovating ways to predict, prevent, detect, and treat animal illness for more than 70 years, Zoetis continues to stand by those raising and caring for animals worldwide – from veterinarians and pet owners to livestock producers. The company's leading portfolio and pipeline of medicines, vaccines, diagnostics and technologies make a difference in over 100 countries. A Fortune 500 company, Zoetis generated revenue of $9.3 billion in 2024 with approximately 13,800 employees. For more information, visit www.zoetis.com.
DISCLOSURE NOTICES
Forward-Looking Statements: This press release contains forward-looking statements which reflect the current views of Zoetis with respect to: our business plans or prospects; expectations regarding products, product approvals or licenses, products under development; and other future events. These statements are not guarantees of future performance or actions. Forward-looking statements are subject to risks and uncertainties. If one or more of these risks or uncertainties materialize, or if management's underlying assumptions prove to be incorrect, actual results may differ materially from those contemplated by a forward-looking statement. Forward-looking statements speak only as of the date on which they are made. Zoetis expressly disclaims any obligation to update or revise any forward-looking statement, whether as a result of new information, future events or otherwise. A further list and description of risks, uncertainties and other matters can be found in our most recent Annual Report on Form 10-K, including in the sections thereof captioned "Forward-Looking Statements and Factors That May Affect Future Results" and "Item 1A. Risk Factors," in our Quarterly Reports on Form 10-Q and in our Current Reports on Form 8-K. These filings and subsequent filings are available online at www.sec.gov, www.zoetis.com, or on request from Zoetis.
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- IRIS stages of kidney disease. Accessed August 21, 2025. https://static1.squarespace.com/static/666b9ecb4064a156963b4162/t/66a6dbc90ca6986e1b5c06bd/1722211273243/2_IRIS_Staging_of_CKD_2023.pdf
- Enomoto M, Mantyh PW, Murrell J, Innes JF, Lascelles BDX. Anti-nerve growth factor monoclonal antibodies for the control of pain in dogs and cats. Vet Rec. 2019;184(1):23.
- L.I. Slingerland, H.A.W. Hazewinkel, B.P. Meij, Ph. Picavet, G. Voorhout, Cross-sectional study of the prevalence and clinical features of osteoarthritis in 100 cats. The Veterinary Journal, Volume 187, Issue 3, 2011, Pages 304-309.
- Solensia Veterinarian A&U MR (MARC 2025)
- Lascelles BDX, Brown DC, Conzemius MG, Gill M, Oshinsky ML, Sharkey M. Measurement of chronic pain in companion animals: discussions from the Pain in Animals Workshop (PAW) 2017. Vet J. 2019;250(8):71-78.
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