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In an unpublished opinion, a federal district court in New Jersey dismissed a class action lawsuit brought by 8 pet owners against Zoetis. 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

Zoetis' bedinvetmab injection 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 bedinvetmab injection, 2 field studies were conducted—1 in the US and 1 in the European Union—made up of client-owned dogs diagnosed with OA. Half of the dogs received bedinvetmab injection and half received a sterile saline injection every 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 assessment tool to measure the dog’s pain and the degree to which it interfered with the patient’s daily activities.2

Based on the evidence collected by both studies, it was demonstrated that the drug was effective at controlling OA pain in dogs when at least 2 doses were given 28 days apart. When announcing the approval, the FDA also listed the common adverse effects, which included the following2:

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

Bedinvetmab injection 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 bedinvetmab injection.4 The new list included ataxia, seizures, and 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 bedinvetmab injection based on postapproval 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 the product launches, with real-world experience data collected. The label update, according to Zoetis, included adding a client information sheet, a postapproval experience section, an 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 [bedinvetmab injection] 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 bedinvetmab injection was approved, it has generated more than 10,000 adverse event reports to the FDA, according to consumers. The plaintiffs in the lawsuit detailed similar experiences using the product, stating 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 (NJPLA), breach of express and implied warranties, negligence, fraud, negligent misrepresentation, and unjust enrichment, according to the release.1

Consumer protection claim

Consumers 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 plaintiff relied on or saw.

Although 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 bedinvetmab injection was safe in their generic assertion was deemed too conclusory to satisfy these requirements, and they failed to quantify the difference between the value received and the value promised.

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

NJPLA claim

The NJPLA claim, which includes failure-to-warn and design defect, was applied to the learned intermediary doctrine by the court. 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.

The court further noted that the NJPLA gave a rebuttable presumption that FDA-approved warnings are adequate, and plaintiffs must allege deliberate concealment or nondisclosure of postapproval risk information. In this case, the 2025 label change was referenced in 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 bedinvetmab injection was defectively designed because there are safer alternatives out there, but it would require speculation that an alternative received FDA approval, and the consumer would have used it.

The consumers also failed to identify any feasible alternative design or allege that bedinvetmab injection's risk outweighs the benefits, which are both necessary elements under the NJPLA; therefore, the NIPLA claim was dismissed.

The consumers were granted leave by the court 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. 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. FDA. 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. Crossley KC. Drug label is updated for pain management therapy. dvm360. 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). FDA. December 16, 2024. 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. February 4, 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