FDA approves pain-management game-changer for cats

The US Food and Drug Administration (FDA) on Thursday approved Zoetis’ Solensia for the control of pain associated with osteoarthritis (OA) in cats. It’s the first monoclonal antibody new animal drug approved by the FDA for use in any animal species.

And it’s likely to be a game-changer.

“The approval of Solensia is a landmark as the first treatment for the control of pain associated with OA in cats,” Margaret Gruen, DVM, MVPH, PhD, DACVB, co-chair of the 2022 AAHA Pain Management Guidelines (coming Spring 2022), told NEWStat. Gruen noted that OA is highly prevalent in cats and is the most common chronic disease they face—it’s estimated that 90% of cats over age 10 are affected by the disease.

Up until now, there haven’t been many options to treat the pain.

Gruen, an assistant professor of behavioral medicine at the North Carolina State College of Veterinary Medicine, said the availability of Solensia would simplify care for feline patients: “As a once-monthly injection, Solensia streamlines care for both the veterinarians and their clients. Veterinarians can feel confident that cats are receiving a treatment that controls their OA pain, while clients won’t have to keep track of, or struggle with, a daily oral administration.”

Over time, OA breaks down the normal cartilage cushion in the joints which leads to the bones in the joint rubbing against each other. This causes pain, less freedom of movement, and potentially, changes in and around the joint that might include bone spurs.

The active ingredient in Solensia is frunevetmab, a synthetic, cat-specific, monoclonal antibody (a type of protein) that recognizes and attaches to nerve growth factor (NGF), another protein which is involved in the regulation of pain. Frunevetmab binds to NGF and prevents the pain signal caused by OA from reaching the brain.

Solensia is administered via an injection under the skin once a month.

Assessing chronic pain levels in cats is notoriously difficult. To determine the effectiveness of Solensia, the FDA used data from two randomized, controlled field studies that measured different aspects of pain associated with OA in cats.

The cats’ veterinarians assessed the cats based on orthopedic examinations before and after treatment. Researchers began with baseline scores provided by owners that included measurements of how easily their cats could perform certain activities such as accessing furniture, grooming, and using the litter box.

Results showed cats in the treatment group faring better than cats in the control group. Side effects in the treatment group were relatively mild and did not require cessation of treatment. These included vomiting, diarrhea, injection site pain, scabbing on the head and neck, dermatitis and pruritus (itchy skin).

Zoetis has been waiting for FDA approval of Solensia for a while—the medication has been commercially available in Europe since May of last year. The company’s research into monoclonal antibody drugs has already proven fruitful in the US: Zoetis’s Cytopoint (which was USDA-approved and used to treat allergies) is another example of a monoclonal antibody product. 

From a clinician’s perspective, this is big news. 

“It's pretty easy to get excited about something that could help us relieve arthritis pain in cats without making them sick, and we just don’t have that many options available right now,” Katie Berlin, DVM, told NEWStat, calling it “a massive development. Cats hate taking pills and owners hate giving them. This is a subcutaneous injection once a month and that’s usually a lot easier to get into a cat than a daily medication.”

Summing it all up—and echoing what’s sure to be the reaction of both veterinarians and cat owners everywhere—AAHA 2022 Pain Management Guidelines Co-chair Gruen said, “It's an exciting day for cats!”

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