Bedinvetmab safety debate sharpens around joint injury reports

A new JAVMA report is intensifying questions around bedinvetmab, the canine anti-nerve growth factor monoclonal antibody marketed as Librela and Beransa, by warning that the drug may be associated with serious safety concerns in dogs, including rapidly progressive osteoarthritis, and by urging vigilant adverse event reporting. That warning adds to a growing body of postmarketing concern around a product that has been widely adopted for canine osteoarthritis pain management. (fda.gov)

Librela entered the U.S. market with considerable clinical interest after FDA approved it on May 5, 2023, as the first monoclonal antibody approved for use in dogs. The product offered a non-NSAID option for osteoarthritis pain control through monthly subcutaneous dosing, and FDA’s original approval materials described common adverse effects seen in studies such as increased blood urea nitrogen, urinary tract infection, bacterial skin infection, dermatitis, vomiting, and weight loss. (fda.gov)

The safety conversation changed materially in late 2024. In a Dear Veterinarian letter dated December 16, 2024, FDA said it had completed an evaluation of adverse events reported in dogs treated with Librela and highlighted neurologic and urinary signs including ataxia, seizures, paresis, recumbency, urinary incontinence, polyuria, and polydipsia. FDA also said some reports listed death, including euthanasia, as an outcome, and noted that it is posting Librela adverse event reports on a rolling basis through its FOIA electronic reading room. (fda.gov)

What’s different in the newer literature is the emphasis on possible musculoskeletal injury, not only symptom control. A 2025 Frontiers in Veterinary Science paper examined musculoskeletal adverse event reports associated with bedinvetmab and explicitly discussed signals involving rapidly progressive osteoarthritis and accelerated joint destruction. Separately, a case report in Veterinary Anaesthesia and Analgesia described a dog with severe and rapidly progressing radiographic changes during bedinvetmab treatment, with the authors concluding that rapidly progressive osteoarthritis was a potential cause after other explanations were ruled out. More recently, a 2026 review in Companion Animal proposed two possible adverse joint patterns linked to bedinvetmab: one resembling rapidly progressive osteoarthritis and another involving more gradual periarticular mineralization and exostotic change. (frontiersin.org)

Industry and scientific reaction has been mixed. Zoetis said in a 2025 announcement about a U.S. label update that, with nearly 25 million doses distributed globally, no individual adverse event signal had been reported above the EMA’s “rare” threshold, and it pointed to updated labeling as part of ongoing pharmacovigilance. At the same time, commentary published in response to the Frontiers musculoskeletal paper argued that the underlying analysis had important methodological limitations, underscoring that the current debate is not settled and that signal detection from spontaneous reports remains inherently imperfect. (news.zoetis.com)

Why it matters: For veterinary professionals, the practical takeaway is not simply whether bedinvetmab is “safe” or “unsafe,” but that case selection, monitoring, and documentation may need to become more disciplined. The U.K. Veterinary Medicines Directorate’s current safety information, updated in January 2026, highlights several points directly relevant to practice: dogs should return to exercise gradually after pain relief improves mobility, there are no long-term safety data for concurrent NSAID use with bedinvetmab, and human anti-NGF programs have reported rapidly progressive osteoarthritis, especially at higher doses and with prolonged NSAID coadministration. While dogs do not have a formally recognized equivalent syndrome in the same way humans do, those warnings suggest clinicians should think carefully about multimodal plans, follow-up timing, and whether worsening lameness after initial improvement could reflect more than background osteoarthritis progression. (gov.uk)

The JAVMA framing around vigilant adverse event reporting also matters because postapproval safety signals depend heavily on what clinicians submit. FDA specifically asks for a full medical history, treatment chronology, number of Librela doses, and vial lot number when reporting suspected events. That level of detail may be especially important in cases involving sudden functional decline, new neurologic signs, unexpectedly rapid radiographic change, or dogs receiving concurrent NSAIDs or other osteoarthritis therapies. (fda.gov)

What to watch: The next phase is likely to center on whether regulators or the sponsor translate these accumulating reports into further label revisions, stronger prescribing cautions, or prospective studies designed to clarify incidence, risk factors, and causality. For clinics, the near-term watchpoints are straightforward: better informed consent discussions with pet parents, closer follow-up after early doses, and lower thresholds for filing detailed adverse event reports when a dog’s course looks atypical. (fda.gov)