Nerve Growth Factor (NGF) Deficiency Syndrome, aka adverse effects of Librela
What happens when NGF is blocked in the body?
Nerve Growth Factor (NGF) was discovered in the 1950s, and science still does not fully understand all of its roles in the mammalian body. We are rapidly finding out what happens when certain species of animals do not have it, particularly felines and canines, who have been administered monoclonal antibodies that bind and inactivate NGF.
In December 16, 2024, the FDA sent a letter to veterinarians updating the adverse effects noted from Librela and amending the client information sheet.
I have personally seen over 50 cases of dogs post-Librela, enough to propose that the list of adverse effects from the client information sheet describes
“NGF deficiency syndrome”:
balance problems, ataxia, difficulty walking
weakness, trouble standing, with the addition of severe, acute muscle atrophy
paralysis
seizures
drinking more
urinating more
loss of bladder control, urinary incontinence
vomiting and diarrhea
These signs are unlike similar signs in other disease conditions. They do not follow the natural course of typical geriatric degenerative diseases like arthritis, degenerative myelopathy, kidney failure ( kidney values are often only mildly increased), or even endocrine diseases like Cushing's, which causes increased drinking and urination.
Rather, they come on suddenly and often have an up-and-down course, with good days followed by bad. The weakness and loss of muscle are extreme in many of them. And they do not respond to allopathic or holistic treatments, such as acupuncture, massage, or supplementation.
I am a trained, licensed veterinarian with post-doctoral training in traditional Chinese Veterinary Medicine (TCVM). TCVM looks for patterns of disease. The TCVM pattern that comes closest to this grouping of signs is Sinking Spleen Qi, “the rug being pulled out from under one.”
There is also a component that is interfering with the neuromuscular junction and neurodegeneration. It appears that patients who have any underlying neurological deficit that may not be expressed clinically, that deficit is becoming unmasked by the lack of NGF. Everything from seizures, degenerative myelopathy, vestibular syndrome, tremors, and even intervertebral disk disease has appeared acutely in some of these patients.
Musculoskeletal adverse events in dogs receiving bedinvetmab (Librela)
On May 8, 2025, Frontiers in Science published a landmark study titled “Musculoskeletal adverse events in dogs receiving bedinvetmab (Librela).” The study's authors were 18 independent veterinarians.
Its findings were horrific, although not surprising, given the results of the human clinical trials and the role of NGF in the body.
Here are some of the findings:
“Ligament/tendon injury, polyarthritis, fracture, musculoskeletal neoplasia (cancer), and septic arthritis were reported ~9-times more frequently in Librela-treated dogs than the combined total of dogs treated with the comparator drugs (Rimadyl®, Metacam®, Previcox®, Onsior®, Galliprant®, and Daxocox)”
“A review of 19 suspected musculoskeletal adverse events (MSAEs) by an 18-member expert panel unanimously concluded a strong suspicion of a causal association between bedinvetmab (Librela) and accelerated joint destruction.”
“NGF modulates bone and cartilage turnover, and its inhibition is linked to accelerated joint degeneration in humans . This was evidenced in 2012, when clinical trials of anti-NGF mAbs (aNGFmAbs) revealed rapidly progressive osteoarthritis (RPOA) , leading the FDA to impose a two-year clinical trial hold and mandate a risk evaluation and mitigation strategy (REMS) post-hold. However, even with stringent screening, low dosing, and NSAID prohibition after the REMS was implemented, RPOA risk persisted.”
They had this information BEFORE it was released for use on dogs and cats.
“Since its European release, Librela has accumulated 20 times more reports than the highest-ranking comparator drug (Rimadyl) and three times more than all comparator drugs combined over a 20-year period.”
“When viewed in context, bedinvetmab’s limited pre-marketing clinical trials raise serious concerns. Only 89 dogs received more than three doses, and crucially, no radiographic screening for accelerated joint degeneration was conducted.”
It well worth scrolling through the study to the radiographs and CT images pre- and post injection. As they say, a picture tells a 100 words.
The paper does a wonderful job at discussing bias inherent in the reporting system and makes comparisons to other drugs, such as NSAIDS and the opioid crisis that is well worth reading.
Final statement of the study:
“An FDA panelist involved in the adjudication of humanized aNGFmAbs eloquently summarised our current belief: “All parties agree that the use of aNGFmabs is effective, but they are associated with a unique, rapidly progressing form of OA…and we can only speculate as to its causes.” In animals, just as in humans, the goal of effective pain management is paramount. However, we must also ensure that our therapeutic interventions do not inadvertently exacerbate the underlying condition. To uphold the highest standard of care for companion animals, we hope to apply the same rigorous scrutiny to veterinary mAbs as was employed in human healthcare.”
Conclusion:
In many ways, Librela is veterinary medicine’s version of the COVID-19 mRNA vaccines. As citizens, we will all be confronted with the decision to take a new medication or gene product repeatedly in the future, whether we have a medical background or not.
It is obvious from the opioid crisis, COVID, and multiple other medications that pharmaceutical companies can release untested products to the general population, human or animal, with very few repercussions, and in many cases, legal protection.
It is also evident that many general practitioners, human and veterinary, are not being taught how to evaluate a new drug or pharmaceutical product regarding safety and efficacy. Drug company representatives cannot be relied upon to give accurate, thorough information. In veterinary medicine, the clinical trials they do in humans are performed on the general population of pets, that is, your dog or cat, within the first few years the drug is in use.
It is up to us, personally, to educate ourselves to discern whether we want to administer such products to ourselves or our loved ones, two-footed or four-footed.
I will continue to provide updates here, and hopefully, this product will be pulled from the market until more research can be done.
I will continue to see dogs and cats affected by these products and try various modalities to keep them comfortable and ease their way along the path.
Please share with fellow animal lovers, friends, and family so people can choose differently.
Holy cow! The images are very helpful impact-wise. "In many ways, Librela is veterinary medicine’s version of the COVID-19 mRNA vaccines." That's exactly what I was wondering as I read your fantastic article.
Dr Josie I found you via another site. My dog has had 4 shots. Her platelets and rbc have bottomed out... Liver kidneys enlarged... I'm so worried. What do I give her to counteract librela? Doctor is treating her with prednisone. She took her off adequan. Nothing else but waiting for her to succumb. Please help!