Health Canada approves novel therapy for managing feline OA

Health Canada has approved relfovetmab injection (Portela; Zoetis) for alleviating pain associated with feline osteoarthritis (OA). The therapy is designed to reduce OA pain for 3 months with a single injection.1

“Health Canada’s approval of [relfovetmab injection] marks a significant step forward in managing osteoarthritis-related pain in cats,” Rob Polzer, PhD, executive vice president and president, research and development for Zoetis, said in a news release.1

Zoetis is anticipating relfovetmab injection to be available on the commercial markets in both Canada and Europe in 2026. The therapy received marketing authorization from the European Commission in October 2025. 1,2

A monoclonal antibody (mAb), relfovetmab injection works by targeting anti-nerve growth factor (NGF), a mediator of OA pain and inflammation. “Thanks to [relfovetmab injection’s] long-lasting antibody and its unique binding site to NGF, veterinarians and cat owners in Canada now have a new, innovative way to address osteoarthritis pain,” Polzer said.1

Up to 40% of all cats and up to 90% of felines older than 12 years are clinically affected by OA, a common, chronic and progressive joint disease.3,4 OA leads to inflammation and breakdown of joints, with negative consequences to gait and movement, as well as sleep, relationships and cognition affected by OA-associated pain. Therapies can help reduce pain and mobility issues caused by the disease and improve quality of life for patients.1

“[Relfovetmab injection] is…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 3 months," Richard Goldstein, DVM, DACVIM, DECVIM-CA, global chief medical officer and head of medical affairs at Zoetis, said in a news release.1 "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."

In earlier 2025, Health Canada also approved Zoetis’ canine mAb therapy designed to reduce pain for 3 months: izenivetmab injection (Lenivia). Like relfovetmab injection, izenivetmab requires a single administration.5

Additionally, in November 2025, Zoetis received marketing authorization in Europe for izenivetmab.6 The authorization followed a positive opinion from the Committee for Veterinary Medicinal Products (CVMP) of the European Medicines Agency.5

A 9-month field trial in Europe demonstrated effectiveness for relfovetmab injection in alleviating OA pain. Published by the International Renal Interest Society, the study found the therapy to be well tolerated, including by cats identified with kidney disease at IRIS stage 1, 2 or 3.7

References

1. Zoetis receives Health Canada approval for Portela (relfovetmab injection) to alleviate pain associated with osteoarthritis in cats. News release. Zoetis. December 5, 2025. Accessed December 5, 2025. https://news.zoetis.com/press-releases/press-release-details/2025/Zoetis-Receives-Health-Canada-Approval-for-Portelarelfovetmab-injection-to-Alleviate-Pain-Associated-with-Osteoarthritis-in-Cats/default.aspx
2. Crossley KC. Long-acting therapy for relieving OA pain in cats receives European marketing authorization. dvm360. October 29, 2025. Accessed December 5, 2025. https://www.dvm360.com/view/long-acting-therapy-for-relieving-oa-pain-in-cats-receives-european-marketing-authorization
3. 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. doi:10.1136/vr.104590
4. Slingerland LI, Hazewinkel HAW, Meij BP, Ph. Picavet, G. Voorhout, Cross-sectional study of the prevalence and clinical features of osteoarthritis in 100 cats. Vet J. 2011;187(3):304-309. doi:10.1016/j.tvjl.2009.12.014
5. Crossley KC. Novel therapy for canine OA pain gains momentum in global markets. dvm360. October 16, 2025. Accessed December 5, 2025. https://www.dvm360.com/view/novel-therapy-for-managing-canine-oa-pain-gains-momentum-in-global-markets
6. Crossley KC. Long-acting drug for reducing canine OA pain receives European marketing authorization. dvm360. November 26, 2025. Accessed December 5, 2025. https://www.dvm360.com/view/long-acting-drug-for-relieving-canine-oa-pain-receives-european-marketing-authorization
7. International Renal Interest Society. IRS staging of CKD. International Renal Interest Society. 2023. Accessed December 5, 2025. https://static1.squarespace.com/static/666b9ecb4064a156963b4162/t/66a6dbc90ca6986e1b5c06bd/1722211273243/2_IRIS_Staging_of_CKD_2023.pdf