Judge drops class action lawsuit against Zoetis over Librela

In an unpublished opinion, a federal district court in New Jersey dismissed a class action lawsuit brought by 8 pet owners against Zoetis, Inc. The lawsuit was brought forward over allegations that Zoetis misrepresented the safety of its bedinvetmab injection (Librela; Zoetis), a monoclonal antibody treatment for osteoarthritis(OA) pain in canine patients. According to a release, the third amended complaint alleged that Zoetis failed to adequately warn veterinarians and clients about severe adverse events that are associated with Librela such as neurological injuries, musculoskeletal problems, hepatic and pancreatic damage, and even death.

Background

Librela received FDA approval for the control of pain associated with OA in canine patients on May 5, 2023, which made it the first monoclonal antibody approved by the FDA for use in dogs. To evaluate the effectiveness of Librela, 2 field studies were conducted, one in the US and one in the European Union made up of client-owned dogs diagnosed with OA. Half of the dogs received Librela and half received a sterile saline injection very 28 days for a total of 3 doses. Prior to the treatment and on different days throughout the study, owners used the Canine Brief Pain Inventory (CBPI) assessment tool to get a measurement of the dog’s pain and the degree to which that pain interfered with the patient’s daily activities.²

Based on the evidence collected by both studies, demonstrated the drug was effective at controlling OA pain in dogs when at least 2 doses are given 28 days apart. The FDA, when announcing the approval, also listed the common side effects to be²:

• Increased blood urea nitrogen
• Urinary tract infection
• Bacterial skin infection
• Skin irritation
• Rash
• Pain at injection site
• Emesis

• Anorexia

Librela was introduced to the marketplace in October 2023 after being determined as safe and effective for its use.³

Earlier this year, the FDA released a Dear Veterinarian Letter to notify veterinary professionals about adverse events that were reported in dogs being treated with Librela.⁴ The new list included ataxia, seizures, other neurologic signs, including but not limited to paresis, recumbency, urinary incontinence, polyuria, and polydipsia. The letter also stated that in some cases, death, including euthanasia, was reported as the outcome of these adverse events.

In February 2025, Zoetis announced that it had updated its US label for Librela based on post-approval experience with the drug in the US since its launch. Label updates are not uncommon for pharmaceutical products, and they tend to occur in the first few years after it launches and with real-world experience data is collected. The label update, according to Zoetis, included adding a client information sheet, post-approval experience section, information for dog owners section, and a statement in the dosage and administration section about the client information sheet, as well as potential adverse events.³

“Every medicine has potential benefits and risks, and it’s important for pet owners to work closely with their veterinarians to weigh those appropriately and maintain an open dialogue about their pets’ experiences…We stand firmly behind Librela, and the positive impact it is having on dogs that suffer from osteoarthritis pain,” Richard Goldstein, DVM, DACVIM (SAIM), DECVIM-CA, said in a Zoetis release.⁵

The lawsuit

Since Librela was approved, it has generated over 10,000 adverse event reports to the FDA, according to consumers. The plaintiffs in the lawsuit detailed similar experiences using the product, that they consented to the injections based on representations that the drug was safe, their dogs then subsequently developed serious health problems, and they incurred veterinary expenses and emotional distress. The consumers contended that adequate warnings should have prevented their consent and altered veterinarians’ prescribing decisions.¹

The complaints then asserted 12 causes of action, including violations of consumer protection statutes from New Jersey, California, Illinois, Missouri, Texas, and Virginia, as well as claims under the New Jersey Products Liability Act, breach of express and implied warranties, negligence, fraud, negligent misrepresentation, and unjust enrichment, according to the release.¹

Consumer protection claim

Consumer alleged violations of California, Missouri, Virginia, Texas, and Illinois consumer protection statutes, but the court found that the complaint failed to identify any specific affirmative misrepresentation that any plaintiffs relied upon or saw.

While each state's statute differs in detail, the court noted that all generally require the plaintiff to allege deceptive or unlawful conduct, actual reliance or causation, and ascertainable loss in some form. The consumers' statement that they believed Librela was safe in their generic assertion was deemed too conclusory to satisfy these requirements, plus they failed to quantify the difference between the value received and the value promised.

It was also acknowledged by the court that the New Jersey Supreme Court explained claims alleging inadequate warnings must typically be brought under the New Jersey Products Liability Act (NJPLA) instead of consumer fraud statutes, unless plaintiffs plead affirmative misrepresentation distinct from failure-to-warn theories. The court, however, permitted the consumers in the alternative to reassert consumer protection claims if they satisfied each state’s pleading requirements.¹

New Jersey Products Liability Act claim

The New Jersey Products Liability Act (NJPLA) claim, which includes failure-to-warn and design defect, the court applied the learned-intermediary doctrine. Under this, a drug manufacturer satisfies its duty to warn by providing sufficient warnings to the professionals prescribing medications, who then convey risks to clients. The court found that the complaint was deficient because it did not allege veterinarians relied on any specific Zoetis materials nor did it identify any advertisement consumers saw.

It was further noted by the court that the NJPLA gave a rebuttable presumption that FDA-approved warnings are adequate, and plaintiffs must allege deliberate concealment or nondisclosure of post-approval risk information. In this case, the 2025 label change was referenced by the complaint, and it alleged that no facts showed that Zoetis was withholding newly discovered risks.

In regard to design defect theory, the court found potential preemption issues because once approved by the FDA, federal laws prohibit unilateral changes to drug formulation. The consumers alleged that Librela was defectively designed because there are safer alternatives out there, but it would require speculation that an alternative receive FDA approval, and the consumer would have used it.

The consumers also failed to identify any feasible alternative design, or allege that Librela’s risk outweighs the benefits, which is both necessary elements under the NJPLA, therefore the NIPLA claim was dismissed.

The consumers were granted by the court leave to amend and file a fourth amended complaint addressing the deficiencies identified in the court’s opinion.

References

1. Biddle W. VETERINARY DRUGS—D.N.J.: Pet owners' class action against Zoetis over Librela arthritis drug dismissed, (Oct 20, 2025). October 20, 2025. Accessed October 22, 2025. https://www.vitallaw.com/news/veterinary-drugs-d-n-j-pet-owners-class-action-against-zoetis-over-librela-arthritis-drug-dismissed/hld014265ab6fa5714a898ec56bb5b3dc7559?refURL=https%3A%2F%2Fwww.google.com%2F#.
2. FDA Approves First Monoclonal Antibody for Dogs with Osteoarthritis Pain. News release. US Food and Drug Administration. May 5, 2023. Accessed October 22, 2025. https://www.fda.gov/animal-veterinary/cvm-updates/fda-approves-first-monoclonal-antibody-dogs-osteoarthritis-pain?utm_medium=email&utm_source=govdelivery
3. K Crossley. Drug label is updated for pain management therapy. February 4, 2025. Accessed October 22, 2025. https://www.dvm360.com/view/drug-label-is-updated-for-pain-management-therapy
4. Dear Veterinarian Letter notifying veterinarians about adverse events reported in dogs treated with Librela (bedinvetmab injection). News release. US Food and Drug Administration. Accessed October 22, 2025. https://www.fda.gov/animal-veterinary/product-safety-information/dear-veterinarian-letter-notifying-veterinarians-about-adverse-events-reported-dogs-treated-librela
5. Zoetis Announces U.S. Label Update for Librela® (bedinvetmab injection), a Treatment to Control Canine Osteoarthritis (OA) Pain. News release. Zoetis, LLC. February 2, 2025. Accessed October 22, 2025. https://investor.zoetis.com/news/news-details/2025/Zoetis-Announces-U.S.-Label-Update-for-Librela-bedinvetmab-injection-a-Treatment-to-Control-Canine-Osteoarthritis-OA-Pain-2025-iu22I1cCqp/default.aspx