Osteoarthritis therapies widen for dogs and cats, but diagnoses lag

By Daniel Okafor

What is the diagnosis gap?

Only 18% of cats worldwide receive a veterinary diagnosis of osteoarthritic pain, and only about half of dogs with OA pain receive treatment.

Dr Richard Goldstein, Zoetis global chief medical officer and head of medical affairs, presented those figures at a meeting in Belgium at the end of October. Around 40% of dogs show OA pain, and a large proportion of cats have clinical signs. Dr Beatriz Monteiro, Zoetis veterinary operations and outcomes research director, later cited 23% as the canine diagnosis rate.

Those percentages came from company presentations, and the meeting report did not state a sample size, study design or follow-up period. "Pain can lead to more pain if left uncontrolled," Dr Goldstein said. "If we miss pain today, it can make tomorrow's pain worse."

Pain remains under-recognized and undertreated in both companion-animal species.

What do the new treatments target?

Dr Goldstein described nerve growth factor, or NGF, as a pain-amplifying signal that becomes elevated in OA joints and drives pain signaling. He said the therapeutic goal is to reduce pain sensitivity within the joint, and lowering NGF is one way to reduce OA pain.

Scott Knauer, Zoetis vice-president in global therapeutics, said the monoclonal antibodies used in the company's latest products were proving viable and successful for companion animals. He identified likely applications in atopic dermatitis, chronic kidney disease, cardiac diseases and oncology, although the meeting report included no comparative trial results for those uses.

The treatment strategy targets pain amplification, while the wider disease applications remain likely possibilities rather than reported clinical outcomes.

How should clinics identify pain?

Dr Monteiro said pain harms animal welfare and linked that principle to the five freedoms: freedom from hunger and thirst; discomfort; pain, injury or disease; normal behaviour; and fear and distress. She said clinicians should pursue five positive domains instead: nutrition, environment, mental state, health and behavioural interactions.

Dr Monteiro said chronic pain acts as a disease in itself, affecting pets from sleep to social relationships. She called effective pain management fundamental to OA treatment and described canine and feline OA as silent epidemics.

Dr Ignacio Calvo, head of surgery at the clinical veterinary hospital of Madrid University, said: "Not every treatment or medication works in every patient." Dr Louise Turley, director of Mulberry House Vets, which has two surgeries in Berkshire, said OA care also needs multimodal treatment, including acupuncture.

Turley said veterinarians and nurses are getting better at asking about pain. She advised using the annual health check for those questions and having clients complete a questionnaire beforehand.

Small changes in a pet's life can reveal pain, Turley said. Caregivers should never feel guilty for missing those clues, she said, because treatment should begin before a patient struggles and pain can also reduce the caregiver's quality of life.

Routine questions can expose pain before patients begin to struggle.

What changes for dogs and cats?

Dr Turley has begun using Lenivia (izenivetmab), a new monoclonal antibody therapy developed by Zoetis for pain associated with OA in dogs. It targets NGF and provides up to three months of relief with one injection.

Zoetis has launched Portela (relfovetmab) for cats, intended to provide up to three months of relief with a single injection. The meeting report specified no authorization status for either product under the FDA Center for Veterinary Medicine, European Medicines Agency or USDA.

Turley checks with clients about six weeks after an injection to see how the animal is faring. Dr Goldstein said the company wanted to encourage chronic treatment of chronic pain and urged owners to search proactively for pain signs. He said early recognition and early treatment improve quality of life for dogs and cats, and that veterinarians and owners should recognize pain so pets can have years free from it.

Dr Monteiro said she hoped every animal in every clinic would undergo pain assessment using validated tools. The products extend treatment intervals, but earlier recognition remains central to improving quality of life.

What does the manufacturing milestone mean?

The meeting also marked the 50th anniversary of a pharmaceutical manufacturing site in Louvain-la-Neuve, Belgium. Opened by Syntex in 1976, the site later became part of Pfizer and transferred to Zoetis in 2013.

The site produces 838 references of vaccines and biopharmaceutical injectables and supplies 116 countries with products for companion animals, cattle, pigs and equines. Last year, it produced 41.9 million vials, including single-dose and multidose presentations.

The operation connects global vaccine and biopharmaceutical production with distinct companion-animal and food-animal markets.

Which implications matter?

• Companion animals: Two monoclonal antibody options for OA pain provide up to three months of relief after one injection, alongside a continuing need for earlier diagnosis and follow-up.
• Food animals: The meeting presented no cattle, pig or equine treatment data; its food-animal contribution was manufacturing for those species.
• Public health: The report presented no zoonotic-disease, food-safety or antimicrobial-resistance findings.

The next measure of progress is whether routine screening and three-month pain control raise diagnosis rates and reduce untreated OA pain in dogs and cats.