FDA: Adverse events in dogs reported with monoclonal antibody drug

The Food and Drug Administration (FDA) has issued a “Dear Veterinarian Letter” regarding reports of adverse events in dogs treated with Librela (bedinvetmab injection). The monoclonal antibody drug is used for the control of pain associated with osteoarthritis in dogs.

Librela was approved by the FDA on May 5, 2023, and introduced to the market later that year. The drug is administered as a monthly subcutaneous injection and was deemed safe and effective for its intended use based on preapproval studies. However, since its release, veterinarians and pet owners have reported adverse events, prompting the FDA to conduct an evaluation.

Adverse events identified and reviewed for Librela include neurological signs, such as ataxia, seizures, paresis, and recumbency. Other clinical signs include urinary incontinence, excessive thirst, and urination. In some cases, death, including euthanasia, was reported as an outcome.

As of April 18, 2024, the FDA Center for Veterinary Medicine’s database included 3,674 reports associated with Librela. Summaries of these reports are available through the FDA CVM’s FOIA Electronic Reading Room.

Two-thirds of the adverse event reports indicated clinical signs occurring within the first week after administration; 30% of these signs occurring within the first day, according to the FDA’s findings. Signs were observed after the initial dose of Librela in 70% of the reported cases. Approximately 30% of the cases reported showed no concurrent use of other products.

Veterinarians are encouraged to report adverse events observed in dogs receiving any drug. Reports associated with Librela can be submitted directly to Zoetis, the drug’s manufacturer, by calling 1-888‑963-8471, or to the FDA through its online reporting system. To assist with investigations, veterinarians are encouraged to provide detailed medical histories, the number of doses administered, and especially the lot number of the product used.

The FDA emphasized its ongoing efforts to monitor the safety of veterinary drugs once they are available on the market. While preapproval testing assesses safety and efficacy, widespread use can sometimes reveal issues that were not previously identified. Drug manufacturers are required to report adverse events to the FDA, which evaluates these reports and may recommend updates to labeling, additional studies, or more frequent monitoring. However, the FDA currently lacks the authority to mandate safety-related labeling changes.