Librela in 2026. What have we learned?
Last year I wrote an update on Librela after a number of new studies, FDA reports and changes to the Librela product information had become available.
At the time, the most recent research was a May 2025 paper by Dr. Mike Farrell and colleagues looking at reports of musculoskeletal adverse events in dogs receiving Librela.
That study generated a lot of discussion.
Some researchers and clinicians felt the findings raised an important safety signal that needed further investigation. Others criticized the methods used and cautioned against interpreting adverse event reports as proof that Librela caused those problems.
So, what has happened since? Quite a bit.
We now have more research showing that Librela can reduce osteoarthritis pain and improve function. At the same time, additional papers have examined concerns about unusual and rapidly progressing changes in the joints of some dogs receiving Librela. In my daytoday practice I’ve noted a lot more caution with Librela from many owners and it appears that less vets are reaching to Librela as first line treatment.
As with my previous blogs, the goal isn't to tell you whether your dog should or shouldn't receive Librela. Rather, it's to help you understand what the research is telling us so you can have an informed conversation with your veterinarian.
A Quick Recap: Where We Left Off in 2025
Librela, or bedinvetmab, is a monoclonal antibody used to reduce pain associated with osteoarthritis in dogs. Dogs with osteoarthritis have more NGF (nerve growth factor) which increases pain signals being sent to the brain. Librela reduces the amount of NGF, thus reducing pain. What is important to remember is that NGF has many roles throughout the body including within the nervous and cardiac systems.
In 2025, the research was clear that Librela is effective at reducing osteoarthritis pain. It was also known that post-market surveillance had identified adverse events that had not necessarily been apparent in the original clinical trials. These included neurological signs, urinary changes and musculoskeletal problems.
The May 2025 Farrell paper raised another concern: musculoskeletal adverse events, including ligament/tendon injuries, fractures and unusual joint destruction, were being reported disproportionately in dogs receiving Librela compared with dogs receiving several other osteoarthritis medications. What hasn’t been proven is that Librela caused these problems.
Several commentaries were subsequently published debating the methods used in the Farrell study. Some supported the need for further investigation, while others—both from Zoetis researchers and independent authors—raised significant concerns about the statistical analysis, reporting bias, selection of cases and lack of an untreated comparison group.
This blog will review what has happened since May 2025.
August 29, 2025 – Could Rapidly Progressive Osteoarthritis Be Biologically Plausible?
Mobasheri and colleagues looked specifically at rapidly progressive osteoarthritis (RPOA) and anti-NGF medications. This was a commentary and not a research paper.
The authors asked whether the joint changes being reported in some dogs could plausibly be related to blocking NGF which results in increased joint use and subsequent damage from that use.
The authors suggested that using NSAIDs and anti-NGF medications together be closely monitored as this is known to cause RPOA in humans, however the same risk combination has not been established in dogs. They suggest vets be aware of signs of RPOA and report them as they occur in order to monitor for adverse events.
February 10, 2026 - Librela compared with Grapiprant
Researchers compared Librela (bedinvetmab) with grapiprant (Galliprant) in 32 dogs with osteoarthritis of the hips and/or knees. This study assessed change through owner questionnaires, force plate gait analysis and vet joint pain assessment.
Research Findings
68.8% of dogs receiving Librela and 56.3% of dogs receiving grapiprant met the study's definition of treatment success on force plate testing.
Librela met the study's predetermined criteria for being non-inferior to grapiprant (i.e. Librela effects on treating arthritis pain was no worse than grapiprant)
Owner-reported pain and function improved with both treatments.
Adverse events were consistent with what was already known for both LIbrela and Galliprant
This study showed that Librela and Galliprant are appropriate first line treatment options for arthritis in dogs. The use of a force plate gait analysis removes vet and owner biases. However, because the study was very short (2 months) conclusions about long-term safety cannot be made from this paper.
March 13 2026 – Librela With and Without "Physiotherapy"
This study was of particular interest to me as a physiotherapist. Unfortunately, what this study considered to be “physiotherapy” was very limited and did not include any hands-on therapy or exercise.
The study looked at 30 dogs with hip osteoarthritis receiving either Librela alone or Librela combined with twice-weekly physiotherapy using photobiomodulation (laser) and PEMF (pulsed electromagnetic field) therapy.
Both groups improved over the 90-day study, with greater improvements in the physiotherapy group. What the study pointed out was that this was not a matter of picking one treatment over another, but rather that using a multipronged treatment approach will yield better outcomes. It also noted that the social and cognitive impact of physiotherapy sessions (due to the interactions with the practitioner) may also lead to better outcomes regardless of the treatments provided.
From my point of view as an animal physiotherapist, reducing pain will allow us to work on regaining strength and function and is an important first step in rehabilitation. At Pawsitively Fit, I advocate for a multipronged treatment.
April 25 2026 – Librela in Obese Dogs With Osteoarthritis
A randomized, double-blind, placebo-controlled study looked at 28 obese dogs with osteoarthritis. Most of the dogs in the study were toy and small breed dogs which the authors did note was a limitation and makes the results difficult to extrapolate to large breeds. Dogs in the study had a body condition score (BCS) of 6-9 out of 9
The dogs received either Librela or a placebo on Days 0 and 28 and were followed for 56 days total. Objective measures of activity was attained by having the dogs wear activity monitors.
Research Findings
Dogs receiving Librela:
increased their daily activity by approximately 25.6% by Day 56
had significant reductions in pain scores
maintained thigh muscle mass better than dogs receiving the placebo
showed reductions in estimated body fat percentage
had improved owner-reported quality of life
No adverse effects were reported during the study, but again, long-term risks are not known as the study was only 56 days.
This study shows that reducing pain increases mobility and improves body weight. This was achieved without any other specific weight loss strategies and allowed all of the dogs to maintain muscle mass.
May 5, 2026 - Review of safety data from 4 studies
The authors of this study sought to determine if Librela was safe compared to other interventions for arthritis. They reviewed 4 studies in total:
2 studies did not find an increase in adverse effects following 3 months of treatment with Librela compared to placebo treatment
1 study compared Librela and meloxicam over 2 months and found Librela to have less adverse events
1 study was a disproportionality analysis and showed that Librela had more musculoskeletal adverse events reported than other typical arthritis medications
Note: I have previously discussed all of these studies which can be found in the other Librela blogs
The conclusion? There is conflicting safety results but generally, Librela appears safe when used for less than 3 months
May 7 2026 - Review of proposed causes of Librela related adverse joint events
Scottish veterinary surgeon Andrew Armitage published a paper describing unusual joint changes observed in some dogs receiving bedinvetmab in his clinical practice.
This wasn't a controlled study. Instead, a veterinarian working in a musculoskeletal referral practice described a pattern of unusual X-ray findings he had been seeing in some dogs treated with Librela, particularly dogs receiving it for longer periods of time.
In addition to the rapidly progressive joint destruction discussed in other papers, he described dogs developing unusually large amounts of new bone and mineralized tissue around affected joints. Some of these changes extended well beyond what he considered typical for osteoarthritis.
Dr. Armitage raises the possibility that blocking nerve growth factor could play a role. Although NGF is involved in transmitting pain (which is why Librela targets it) it also has other functions within bone, cartilage and tissue repair. This is a hypothesis rather than a proven mechanism.
There are some important limitations that Dr. Armitage notes:
many of the dogs did not have X-rays taken before starting Librela, making it difficult to know exactly when the changes began or how quickly they progressed
there was also no comparison group of similar dogs with arthritis that had not received Librela.
This paper cannot state that Librela caused these changes or how frequently they occur. It only shows a relationship.
Dr. Armitage does urge monitoring when a dog is receiving Librela. If a dog that has been doing well on Librela begins becoming increasingly lame or painful again, particularly after months of treatment, it may be worth investigating why rather than simply assuming the medication is becoming less effective. Repeat examination and imaging may help determine whether the underlying joint itself has changed. Unfortunately, stopping Librela does not seem to undo the joint or soft tissue changes. Joints that were most commonly affected by these unwanted changes were the elbow, followed by the digits (ie. toes), capri (wrists), and hocks.
May/June 2026 – More Veterinary Specialists Raise Concerns About RPOA
Studies continue to be published focused on rapidly progressive joint changes.
A May publication by von Pfeil, Armitage and Nelson described emerging observations of severe arthritic changes in dogs receiving Librela and cats receiving the equivalent feline anti-NGF medication, Solensia.
Then, in June, a larger group of veterinary specialists published a JAVMA paper discussing safety concerns associated with Librela, including RPOA, and calling for vigilant reporting of suspected adverse events.
These papers were not randomized control trials that prove Librela causes these changes. Rather they show there is a relationship between joint changes and Librela use. The calls for continued research, screening and reporting are growing more common.
August 2026 – The Largest Look Yet at the Unusual X-Ray Findings
In August, another important paper was published looking specifically at adverse musculoskeletal reports in dogs treated with Librela. Researchers accessed cases from the Zoetis Global Pharmacovigilance database reported between November 2020 and December 2025.
They identified 319 potential musculoskeletal adverse-event cases that contained enough information and imaging to be reviewed.
The researchers categorized the cases as:
insufficient information
changes consistent with normal progression of arthritis
another identifiable orthopedic condition
atypical findings
Of the 319 cases reviewed, 186 were considered to have atypical X-ray findings.
The most common finding was abnormal bone remodelling around the joint with the elbow and tarsus (ankle/hock) were most commonly involved. Some dogs had changes in more than one joint and some changes appeared to progress over time.
Of significant note were that 63% of these dogs were also receiving NSAIDs, and 25% had received Librela in a way considered off-label (e.g. dosing that did not follow than manufacturers instructions).
This paper still does not accurately say how common unwanted joint changes are because this only tells us what adverse events were reported and had further investigation.
So where are we in 2026?
The research is pointing to a relationship between Librela usage and rapidly progressing joint degeneration and mineralization of soft tissues around joints. The risk of these occurring appear to be higher in dogs also receiving NSAIDs at the same time. However, it cannot be concluded that Librela causes these changes. Correlation does not equal causation.
What we know for sure is that Librela can and does improve osteoarthritis pain and function and is safe in short time frames. However, there are still important questions about long-term use and safety.
In particular, we need better information about:
rapidly progressive osteoarthritis
unusual bone and mineral changes around joints
which dogs may be at greater risk
whether concurrent medications influence that risk
whether certain joints or stages of arthritis are more vulnerable
and what happens when dogs receive Librela continuously for years rather than weeks or months
Most importantly, we need studies that follow dogs before they start Librela and over time afterwards, ideally including baseline and follow-up X-rays.
The question remains: Are these unusual joint changes actually occurring more frequently in dogs receiving Librela than they would in similar dogs with osteoarthritis who don't receive it?
What Should Owners Do With This Information?
My concern with Librela from the start has been a lack of owner education prior to injection. While more possible risks have been highlighted since its release, many (even most) dogs who receive this medication do experience positive outcomes. I’m pleased to see more consideration given to the pros and cons of Librela than there was a few years ago.
Librela is a pain medication. Improving pain in dogs with arthritis is paramount. Once pain is reduced, mobility, strength and function is easier to address. Librela does not change the condition within the joint. There is still inflammation, cartilage degradation and progressing disease. Librela (or other pain meds) allow the opportunity to put other strategies in place to slow or stop disease progression.
If your dog receives Librela:
Pay attention to changes rather than just whether the injection worked to reduce pain.
Notice how your dog walks, rises, manages stairs, gets into the car, plays and recovers after activity.
If something suddenly changes, tell your veterinarian.
If a dog that initially did very well on Librela begins becoming increasingly lame or painful again, don't automatically assume that the medication has simply stopped working. A reassessment may be warranted to determine whether something else has changed.
My Thoughts on Librela in 2026
My thoughts on Librela haven’t changed a lot. Librela works very well in some dogs, and not at all in others. I still believe it is a tool or part of a more robust arthritis care plan.
My biggest fear and concern continues to be the “what if” as the most significant joint related adverse effects do not reverse when the drug is stopped. I think this is where a transparent conversation between vet and owner must occur. And it must occur BEFORE Librela is initiated.
I don't believe Librela is inherently "good" or "bad."
I believe it is another tool available to help manage osteoarthritis pain.
For some dogs, particularly those who cannot tolerate other medications or whose pain isn't adequately controlled, it can make a substantial difference in quality of life.
But arthritis management shouldn't begin and end with an injection.
Pain management works best alongside appropriate exercise, maintaining muscle strength, keeping dogs at a healthy body weight, adapting their environment and regularly reassessing how they're moving and functioning.
And as the Librela research continues to evolve, I think owners deserve to know both sides of the story:
There is good evidence that Librela can help arthritis pain.
There are also legitimate unanswered questions about uncommon adverse events and long-term joint health.
Those two things can be true at the same time.
The goal shouldn't be to scare owners away from a potentially useful medication—or to dismiss concerns when something doesn't seem right.
The goal should be to make informed decisions, monitor our dogs carefully and continue adjusting their arthritis plan based on the dog in front of us.
Video: Learn how to provide better care for your arthritic dog
References:
Farrell, Mike, et al. “Musculoskeletal Adverse Events in Dogs Receiving Bedinvetmab (Librela).” Frontiers in Veterinary Science, vol. 12, 2025, article 1581490. https://doi.org/10.3389/fvets.2025.1581490.
Mobasheri, Ali, et al. “Rapidly Progressive Osteoarthritis (RPOA) in Companion Animals Treated with Bedinvetmab (Librela™): An Expected Pathophysiological Phenomenon or a Cause for Concern?” Frontiers in Veterinary Science, vol. 12, 2025, article 1640217. https://doi.org/10.3389/fvets.2025.1640217.
Enomoto, Masataka, et al. “A Noninferiority Trial Evaluating the Efficacy of Bedinvetmab Compared to Grapiprant for Osteoarthritis-Pain in Dogs Using Force Plate Gait Analysis.” Scientific Reports, 2026. https://doi.org/10.1038/s41598-026-37626-4.
Cidral, Letícia Orthey, et al. “Bedinvetmab, Alone or in Combination with Photobiomodulation and Pulsed Electromagnetic Field Therapy, on Pain and Quality of Life in Dogs with Hip Osteoarthritis.” Veterinary Research Communications, vol. 50, no. 3, 2026, article 198. https://doi.org/10.1007/s11259-026-11133-3.
Phongphuwanan, Aujchariyaporn, et al. “Efficacy of Bedinvetmab on Pain, Activity, and Body Composition in Obese Dogs with Osteoarthritis: A Randomized Double-Blind Placebo-Controlled Trial.” Veterinary World, vol. 19, no. 4, 2026, pp. 1595–1610. https://doi.org/10.14202/vetworld.2026.1595-1610.
Yang, X., and P. Macarthur. “A Critical Appraisal of the Safety of Bedinvetmab (Beransa), a Canine Antinerve Growth Factor Monoclonal Antibody.” Australian Veterinary Journal, vol. 104, no. 8, 2026, pp. 549–556. https://doi.org/10.1111/avj.70088.
Armitage, Andrew. “Identification and Possible Pathogenesis of Bedinvetmab-Associated Adverse Joint Events.” Companion Animal, 2026. https://doi.org/10.12968/coan.2026.0009.
von Pfeil, Dirsko J. F., Andrew Armitage, and Nathan C. Nelson. “Emerging Signs of Rapidly Progressive Arthritic Changes in Dogs and Cats Receiving Bedinvetmab and Frunevetmab.” Veterinary and Comparative Orthopaedics and Traumatology, vol. 39, no. 3, 2026, pp. 157–161. https://doi.org/10.1055/a-2846-8347.
von Pfeil, Dirsko J. F., et al. “Bedinvetmab (Librela/Beransa) in Dogs Raises Safety Concerns, Including Rapidly Progressive Osteoarthritis, and Warrants Vigilant Adverse Event Reporting.” Journal of the American Veterinary Medical Association, 2026, pp. 1–11. https://doi.org/10.2460/javma.26.03.0170.
Budsberg, Steven C., et al. “Atypical Radiographic Changes Seen in Dogs Treated with Bedinvetmab (Librela).” Journal of the American Veterinary Medical Association, 2026, pp. 1–9. https://doi.org/10.2460/javma.26.05.0379.
