Animal health company assures veterinarians that OA drugs are safe


This update comes after some pet owners publicly claim bedinvetmab injection (Librela) and frunevetmab injection (Solensia) have worsened their pets’ condition



This article was updated on April 22, 2024.

Zoetis is standing by its osteoarthritis (OA) therapies for dogs and cats in the wake of a published report questioning the safety of the company’s bedinvetmab injection (Librela) and frunevetmab injection (Solensia) products. In a Wall Street Journal article published on April 12, 2024, pet owners claimed their animals were sickened by these drugs rather than seeing the medications' intended improvement of the animals' conditions.1

In one case, according to the news article, a 12-year-old dog was reportedly euthanized within 2 months after an initial dose of bedinvetmab for treatment of a stiff hip. The dog demonstrated a decrease in mobility and appetite, became lethargic and lost kidney function before dying. Similar cases with another dog and a 16-year-old cat that used either bedinvetmab or frunevetmab, respectively, were also documented.1 Since publication, the report has received increased attention on social media platforms.

In an interview with dvm360®, representatives of Zoetis acknowledged adverse effects have been reported in a small number of patients using these drugs. However, they noted that an “overwhelming majority” of patients using bedinvetmab injection and frunevetmab injection have benefitted from them. “There are rare adverse events, like any other medication,” said Richard Goldstein, DVM, DACVIM, DECVIM-CA, global chief medical officer for Zoetis. “We are very confident in the safety and efficacy of Librela and Solensia. We are very confident with the fact that [Librela] is efficacious, that it's helping thousands of dogs worldwide. But [we are] also aware that a small percentage of cases, just like any other drug, have potential side effects.”

Bedinvetmab injection was approved by FDA officials in May 2023, becoming the first monoclonal antibody for dogs suffering from osteoarthritis pain. Bedinvetmab injection is only available by prescription from a licensed veterinarian to ensure the drug is given and monitored for safety and the treatment of any adverse effects.2 These adverse effects include blood urea nitrogen, urinary tract infection, dermatitis, erythema, pain at the injection site, vomiting, weight loss, etc. The drug works by binding to and inhibiting the biological activity of canine nerve growth factor (NGF).2

Officials with the FDA approved frunevetmab injection, the first monoclonal antibody drug for use in any animal species, in January 2022 to treat felines with OA. Frunevetmab injection, a cat-specific monoclonal antibody, also targets NGF, which is elevated in cats suffering from OA and involved in the regulation of pain. The drug works by binding to and inhibiting the biological activity of NGF. Adverse effects include diarrhea, vomiting, injection site pain, scabbing on the head and neck, dermatitis, and pruritus. At the time of the FDA approval, reports on the adverse effects were relatively mild and did not require stopping the injections.3

Duncan Lascelles, BSc, BVSc, PhD, FRCVS, CertVA, DSAS(ST), DECVS, DACVS, professor and director of the Comparative Pain Research and Education Centre, NC State College of Veterinary Medicine, and a Zoetis partner, said that from his perspective, cases of severe adverse reactions being shared on social media are “a small minority” of patient experiences with these drugs. “It's a few instances that, unfortunately, are really blown out of proportion. It doesn't represent this therapeutic, its value, its efficacy, its contribution to veterinary medicine, and certainly is not representative of the risks associated with it,” he said in the interview.

Nicole Martell-Moran, DVM, MPH, DABVP (Feline Practice),a feline specialist, said her practice has “given almost 1000 injections [of frunevetmab] since it was launched in the United States” and has had no reports of death. “Adverse reactions we have seen include face and body itching, loss of appetite for 24 hours post-injection, and self-limiting head tremors.All resolved without complications,” she continued.

According to Martell-Moran, making a claim of injury is difficult with cats being treated for painful arthritis, most likely, at the end of their lives. “There are a lot of diseases processes that can occur suddenly that cause death or there may be many comorbidities that gradually progress, and the end result is death, especially in a senior cat,” she said, in an interview with dvm360. “As with any medication or intervention, there is the potential for side effects. We have to keep an open mind as this is a new drug and the more we administer it, the more experience we will have to report. I have seen it greatly improve the quality of life in my patients and will not stop recommending it but will continue to monitor reports of adverse events to help our clients make an informed decision.”

Educating pet owners can help, Goldstein said. “I think the first thing that’s important to understand is [pet owners] are hurt for a reason. It's very difficult to lose a pet, a family member, and people often want to find a reason to blame. ‘Ever since my dog fell down the stairs, it had this big tumor in his liver.’ And so, falling down the stairs caused him to have a tumor in their liver. People feel the need to find a reason for things that happen. I understand that piece of it…I understand their desire to find a reason for when bad things happen. But we’re treating dogs that have recurrent disease or older dogs, that there's a reasonable chance that something else will happen to that dog, unrelated to whatever treatment or medication we gave. That's hard sometimes to explain, but we need to explain that. And we need to arm the veterinarians who are in contact with the pet owners with the facts so they can help explain to the pet owner, what happened,” he added.

Both Goldstein and Lascelles said they stand by study findings that support the safety of bedinvetmab injection and frunevetmab injection. A clinical trial4 examined 287 dogs given bedinvetmab injection monthly and found that the animals experienced less pain from OA compared with dogs who received a placebo. By alleviating pain, the study found improved mobility and overall quality of life for those using bedinvetmab injection. Although the full effectiveness may not be noticeable until after the second dose of bedinvetmab, some dogs might feel less pain as soon as 7 days after the initial injection. The study also indicated that dogs treated with bedinvetmab injection consistently experienced relief from OA pain with monthly injections.4

According to Goldstein, Zoetis is continuing to investigate the safety and efficacy of these drugs. Continued study is not only required by the FDA, but he said, too, that Zoetis takes seriously its responsibility to patient safety. Goldstein also encouraged veterinarians to contact Zoetis with any questions or needed support. “Anything we could possibly do to make sure that we're all working together to alleviate pain,” he added.

Goldstein also encouraged veterinary professionals to report any patient adverse effects to Zoetis. “We will investigate, and we will do whatever we can to make sure that the drug is used appropriately. Pharmacovigilance is an ongoing, tremendous effort,” he said.

"The death of a pet is heartrending. I feel nothing but sympathy for the loss of these 2 pets. But unfounded accusations and fear mongering does nothing to help, and may hinder the ability of people with pets in pain from OA to seek treatment to attain a better quality-of-life," explained Michael Petty, DVM, exclusively to dvm360.

"As a practitioner who has been treating animals in pain for 44 years, and yes, before the advent of drugs like Rimadyl (carprofen) were introduced back in 1996, I saw many animals suffer needlessly as well as euthanized before their time due to lack of sufficient pain control," he continued.

For Zoetis product support, veterinarians in the US can contact the company’s Veterinary Medical Information Support Team at 1-888-963-8471.


  1. Calfas J. What killed their pets? Owners blame meds, but vets aren’t sure. Wall Street Journal. April 12, 2024. Accessed April 15, 2024.
  2. Coppock K. FDA approves first monoclonal antibody for dogs with osteoarthritis pain. News release. FDA. May 5, 2023. Accessed April 15, 2024.
  3. FDA Approves Novel Treatment to Control Pain in Cats with Osteoarthritis, First Monoclonal Antibody Drug for Use in Any Animal Species. News release. FDA. January 13, 2022. Accessed April 15, 2024.
  4. Corral MJ, Moyaert H, Fernandes T, et al. A prospective, randomized, blinded, placebo-controlled multisite clinical study of bedinvetmab, a canine monoclonal antibody targeting nerve growth factor, in dogs with osteoarthritis. Vet Anaesth Analg. 2021;48(6):943-955. doi:10.1016/j.vaa.2021.08.001
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