Zoetis Inc. has expanded its companion animal pain management portfolio with the launch of Portela® (relfovetmab), the world’s first three-month monoclonal antibody treatment for osteoarthritis pain in cats.
Portela (Relfovetmab) Commercially Available
The product is now available across European Union member states and Canada, offering veterinarians and pet owners a longer-lasting option for managing one of the most common yet frequently overlooked diseases in ageing cats.
The launch, announced on July 22, 2026 marks another milestone in veterinary pain management by introducing a treatment that provides up to three months of pain relief from a single subcutaneous injection. Portela is designed to improve comfort and mobility in cats suffering from osteoarthritis while reducing the need for frequent veterinary visits or repeated monthly injections.
New Option for a Common but Underdiagnosed Disease
Osteoarthritis (OA) is one of the most widespread chronic conditions affecting older cats. Studies suggest that up to 40% of cats show signs of osteoarthritis, with the prevalence increasing significantly as they age. Despite its frequency, the condition often goes undiagnosed because cats naturally conceal pain and discomfort, making the disease difficult for owners to recognise in its early stages.
Unlike dogs, cats rarely limp noticeably when experiencing joint pain. Instead, subtle behavioural changes are often the first warning signs. These may include:
Reluctance to jump onto furniture
Reduced activity levels
Sleeping more than usual
Difficulty climbing stairs
Less grooming
Irritability when handled
Changes in social behaviour
Because these signs are often mistaken as “normal ageing,” many cats remain untreated for months or even years.
How Portela Works
Portela contains relfovetmab, a monoclonal antibody that targets Nerve Growth Factor (NGF), an important protein involved in transmitting pain signals associated with osteoarthritis. When joints become damaged by osteoarthritis, NGF levels increase around affected tissues, contributing to chronic pain.
By binding specifically to NGF, relfovetmab helps interrupt pain signalling before it reaches the nervous system, reducing discomfort without directly affecting the joint itself. Unlike traditional pain medicines that require daily administration, Portela is given as a single injection under the skin every three months, providing long-lasting pain control.
Longer Duration May Improve Treatment Compliance
One of the biggest challenges in feline medicine is administering medication consistently. Many cat owners struggle to give tablets or liquid medicines every day, while repeated veterinary visits for monthly injections may also be difficult for some households.
Portela aims to address these challenges by extending treatment duration from one month to three months.
The longer dosing interval may help improve treatment adherence while reducing stress for both cats and their owners. For veterinary clinics, fewer treatment visits may also make long-term osteoarthritis management more practical for clients.
Expanding Zoetis’ Feline Pain Management Portfolio
Portela joins Solensia®, Zoetis’ monthly anti-NGF monoclonal antibody injection for feline osteoarthritis. While Solensia has become widely adopted for monthly pain management, Portela introduces a new option for veterinarians seeking a longer-lasting treatment schedule.
Together, the two products strengthen Zoetis’ position in the rapidly growing market for biologic therapies in companion animal medicine. The availability of different treatment intervals allows veterinarians to tailor pain management plans according to the needs of individual patients and their owners.
Monoclonal Antibodies Are Changing Veterinary Medicine
Monoclonal antibody therapies represent one of the fastest-growing areas of veterinary pharmaceutical research. Unlike conventional drugs, monoclonal antibodies are highly targeted biological medicines designed to interact with specific molecules involved in disease processes.
Because they work selectively, they may offer effective symptom control while reducing exposure to some of the pathways affected by traditional medications. In recent years, monoclonal antibodies have been developed for conditions including:
Osteoarthritis pain
Allergic skin disease
Chronic pain conditions
Their growing use reflects a broader shift towards precision medicine in companion animal healthcare.
Why Early Diagnosis Matters
Veterinary specialists emphasise that recognising osteoarthritis early can significantly improve a cat’s quality of life. Persistent pain affects more than mobility. It can reduce appetite, limit physical activity, alter behaviour and interfere with normal grooming habits.
Early diagnosis allows veterinarians to introduce pain management strategies before severe mobility problems develop. Regular health checks, especially for cats older than seven years, can help identify subtle signs that owners may overlook at home.
Growing Focus on Healthy Ageing in Cats
As advances in veterinary medicine help pets live longer, age-related diseases such as osteoarthritis are becoming increasingly common. Managing chronic pain has therefore become an important part of improving both longevity and quality of life.
Long-acting therapies such as Portela may play an increasingly important role in comprehensive feline healthcare by making long-term treatment more convenient for both veterinarians and pet owners.
Market Impact
The launch of Portela further strengthens Zoetis’ leadership in companion animal therapeutics and reflects the company’s continued investment in biologic medicines for chronic diseases.
The introduction of a three-month treatment option may also influence future product development across the veterinary pharmaceutical industry, particularly in long-acting therapies designed to improve treatment compliance.
With increasing awareness of feline osteoarthritis and greater demand for convenient treatment options, the market for long-acting biologic therapies is expected to continue expanding over the coming years.
Key Takeaways
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Zoetis has launched Portela® (relfovetmab) in Canada and European Union member states
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Portela is the first monoclonal antibody treatment for cats that provides up to three months of osteoarthritis pain relief from a single injection
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The therapy targets Nerve Growth Factor (NGF), a key molecule involved in chronic osteoarthritis pain
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Osteoarthritis affects up to 40% of cats, but many cases remain undiagnosed because cats often hide signs of pain
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The three-month dosing schedule may improve treatment compliance and reduce the burden of frequent medication or monthly veterinary visits
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Portela expands Zoetis’ feline pain management portfolio alongside Solensia®, providing veterinarians with greater flexibility in managing chronic osteoarthritis pain
