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Zoetis Receives Approval For Portela® (relfovetmab Injection) In Great Britain
2 days ago 
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Zoetis UK Ltd. announced that the UK’s Veterinary Medicines Directorate (VMD) has approved Portela®(relfovetmab injection) for the alleviation of pain associated with osteoarthritis (OA) in cats. Portela is the first long-acting anti-nerve growth factor (NGF) monoclonal antibody (mAb) therapy for cats, designed to alleviate pain associated with osteoarthritis for up to three months with a single subcutaneous injection. Backed by nearly a decade of science and research, Portela demonstrated effectiveness in alleviating OA pain in a pivotal nine-month European field study with improvements observed from as early as Day 3 after the first injection1.
Portela targets NGF, a recognised mediator of pain and inflammation. By binding to a novel site on NGF, Portela enables up to three months alleviation of pain associated with OA with a single injection. In clinical trials, Portela was found to be well tolerated and demonstrated effectiveness in alleviating OA pain.
“Cat owners often face real practical challenges when it comes to managing their pet’s chronic pain; from the difficulty of giving oral medication to the stress of veterinary visits for a species that finds travel particularly unsettling,” said Julia von Gablenz, Regional President Europe and Middle East at Zoetis. “Portela addresses these challenges directly by alleviating the pain associated with OA with a single injection once every three months, making it easier for both veterinary teams and cat owners to maintain consistent care.”
Significance of Osteoarthritis Pain
Osteoarthritis is a common, chronic and progressive joint disease characterised by the inflammation and breakdown of joints, leading to pain and mobility issues. Chronic pain can be difficult to recognise and assess in companion animals2. Up to 40% of all cats may be clinically affected by OA3,4, yet these signs are often overlooked by pet owners, and as a result only 18% of affected cats are diagnosed with OA pain by veterinary professionals5. Cats are naturally inclined to mask pain, and many owners interpret reduced activity or reluctance to jump as normal aging rather than signs of a manageable condition6. Additionally, administering regular oral medication to cats presents a well-known compliance challenge7,8, which results in many cats with OA going undertreated6.
Effective pain management can meaningfully improve quality of life for affected cats9. As cats live longer due to advances in veterinary care and nutrition, the number of senior cats is growing10,11. With age, conditions such as osteoarthritis become more common, highlighting the need for well tolerated, effective long-term pain management options. For millions of cat owners across the UK, the impact on their cats’ quality of life is impossible to ignore. Medications that are more convenient in delivering sustained pain control for this chronic disease fill an unmet need to achieve increased compliance with treatment.
Continued Innovation to Meet Medical Needs
Zoetis continues to advance care for animals around the globe with a robust pipeline fueled by lifecycle innovation, geographic expansion and new innovation. Building on its broad portfolio in osteoarthritis pain, Portela expands the company’s feline OA pain portfolio alongside Solensia®(frunevetmab), an anti-NGF monoclonal antibody indicated for monthly alleviation of OA pain in cats. Portela is designed to provide pain relief for a longer period of time by binding to a different site on NGF, offering the convenience of a single injection once every three months.
1 Zoetis Data on File. Portela GB Summary of Product Characteristics (SPC).
2 Lascelles BDX, Brown DC, Conzemius MG, Gill M, Oshinsky ML, Sharkey ML. Measurement of chronic pain in companion animals: discussions from the Pain in Animals Workshop (PAW) 2017. Vet J. 2019;250:71-78.
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.
4 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.
5 Solensia Veterinarian A&U MR (MARC 2025)
6 Bennett D, Zainal Ariffin SM bt, Johnston P. Osteoarthritis in the cat 1. How common is it and how easy to recognise? J Feline Med Surg. 2012;14:65-75. doi:10.1177/1098612X11432828
7 Odom TF, et al. Medication compliance by cat owners prescribed treatment for home administration. J Vet Intern Med. 2025;39(1):e17298. doi:10.1111/jvim.17298
8 Taylor S, Caney S, Bessant C, Gunn-Moore D. Online survey of owners’ experiences of medicating their cats at home. J Feline Med Surg. 2022;24(12):1283-1293. doi:10.1177/1098612X221083752
9 Gruen, M. E., Myers, J. A. E., Tena, J. S., Becskei, C., Cleaver, D. M., & Lascelles, B. D. X. (2021). Frunevetmab, a felinized anti-nerve growth factor monoclonal antibody, for the treatment of pain from osteoarthritis in cats. Journal of veterinary internal medicine, 35(6), 2752–2762. https://doi.org/10.1111/jvim.16291
10 Han, H. J. (2025). Toward a new era of companion animal longevity and well-being. Journal of Veterinary Science, 26(Suppl 1), S1–S4.
11 Oh, W. S., & Armstrong, P. J. (2025). Geroscience and aging interventions in dogs and cats: from mechanisms to clinical care. Journal of Veterinary Science, 26(Suppl 1), S157–S180.
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