Zoetis Inc. (NYSE: ZTS) has launched Portela (relfovetmab) in Canada and European Union member states, a monoclonal antibody therapy for cats with osteoarthritis pain.

Portela is administered as a single subcutaneous injection once every three months. The company claims it is the first long-acting anti-nerve growth factor monoclonal antibody therapy for cats. Zoetis says the drug demonstrated effectiveness in alleviating osteoarthritis pain in a nine-month European field study, with improvements observed from as early as three days after the first injection.

The drug works by binding to nerve growth factor, a mediator of pain and inflammation, at what the company describes as a novel binding site. Portela is not approved for use in cats with known hypersensitivity to relfovetmab, breeding, pregnant or lactating cats, or cats under 12 months of age. The most common side effect reported in the EU label is immediate pain upon injection, occurring in more than one in 10 cats treated. Dermatitis was reported in one to 10 cats per 100 treated.

Portela joins Zoetis's existing feline osteoarthritis product Solensia (frunevetmab), a monthly anti-nerve growth factor monoclonal antibody for cats. According to the press release, Portela binds to a different site on nerve growth factor than Solensia.

"Feline osteoarthritis remains one of the most underdiagnosed conditions in veterinary medicine, in part because cats instinctively hide signs of pain," said Jamie Brannan, Executive Vice President and Chief Commercial Officer of Zoetis.

According to data cited in the press release, up to 40% of cats may be clinically affected by osteoarthritis, yet only 18% of affected cats are diagnosed with osteoarthritis pain by veterinary professionals.