Developmental drug for feline pain takes a step forward in Europe

A developmental drug targeting pain associated with feline osteoarthritis (OA) has received a positive opinion from the European Medicines Agency (EMA) Committee for Veterinary Medicinal Products (CVMP). With this opinion, the CVMP is recommending marketing authorization for relfovetmab (Portela; Zoetis), a monoclonal antibody (mAb) therapy.¹

Relfovetmab is on track to be the first approved long-acting anti-nerve growth factor (NGF) mAb therapy for cats, according to Zoetis. The company is anticipating the drug to become commercially available in the European Union in 2026.¹

The single injection drug is designed to target NGF, a key mediator of OA pain, and provide 3 months of relief. The CVMP’s recommendation for marketing authorization is based on a positive benefit-risk balance of the safety and efficacy data submitted by Zoetis. Relfovetmab demonstrated effectiveness in alleviating OA pain, in clinical trials. The therapy was also found to be well tolerated, including in felines with kidney disease.¹

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“The CVMP’s positive opinion for Portela represents a significant step forward in advancing feline pain management,” Rob Polzer, PhD, executive vice president and president, research and development with Zoetis, said in a news release.¹ “The long-acting antibody properties of Portela and its unique binding site to NGF will soon offer veterinarians and cat owners in the European Union a new option to alleviate pain associated with osteoarthritis, thereby helping to improve the quality of life for affected cats.”

Although fewer than 20% of felines are diagnosed with OA, up to 40% of cats have clinical signs of the chronic and progressive joint disease.^1,2 According to Kristin Kirby Shaw, DVM, PhD, MS, DACVS-SA, CACVSMR, founder of Canine Arthritis Resources and Education (CARE), “The statistics show that about 60% of cats over the age of 6 have x-ray evidence of arthritis and 90% of cats over the age of 12 have radiographic [OA].²

“Arthritis is very common in cats. As they age, basically all cats are going to develop arthritis similar to how all humans...develop some degree of wear and tear and joint disease,” Kirby Shaw said, in a dvm360 interview.²

OA causes inflammation and breakdown of joints, which leads to pain and mobility issues.¹ “Cats are, importantly, meant to be vertical creatures; they want to jump up [and] get up high. And as their joint disease and their associated pain get worse, it gets harder and harder for them to get up onto those higher surfaces,” Kirkby Shaw said.³

The disease also affects sleep, relationships, and cognition, according to Zoetis.¹ “If they ache and are trying to protect themselves from threats, they might actually pull away from engaging with their family. They may not want to be held or may not want to sit on the couch next to the family,” Kirkby Shaw said.³

Quality of life can be improved with the management of pain associated with OA, and relfovetmab could join Zoetis’ frunevetmab (Solensia) therapy—an anti-NGF monoclonal antibody for monthly relief of pain associated with OA in cats—as another therapeutic option.¹

“If approved, Portela will be a new, science-driven solution 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," Richard Goldstein, DVM, DACVIM, DECVIM-CA, global chief medical officer and head of medical affairs with Zoetis, said in the release. "We look forward to providing veterinarians with another innovative tool to help them improve the quality of life for the animals in their care."

References

1. Zoetis receives positive opinion from CVMP for Portela (relfovetmab) to alleviate pain associate with osteoarthritis in cats. News release. Zoetis. September 12, 2025. Accessed September 12, 2025. https://investor.zoetis.com/news/news-details/2025/Zoetis-Receives-Positive-Opinion-from-CVMP-for-Portela-relfovetmab-to-Alleviate-Pain-Associated-with-Osteoarthritis-in-Cats/default.aspx
2. Kirby Shaw K, Bautista-Alejandre A. Feline arthritis remains underdiagnosed. dvm360. May 22, 2025. Accessed September 12, 2025. https://www.dvm360.com/view/feline-arthritis-remains-underdiagnosed
3. Kirby Shaw K, Bautista-Alejandre A. How osteoarthritis affects cats. dvm360. May 23, 2025. Accessed September 12, 2025. https://www.dvm360.com/view/how-osteoarthritis-affects-cats