FOI release

FOI2026/00195 – Librela drug data sheet

Published 20 March 2026

Your request

I am writing to request the following information regarding your updates on the Librela drug data sheet, Revised: January 2026 AN: 02281/2025 :-

Death is not recorded as a side effect on this update. The US FDA who are actively gathering information to protect people and their pets quote DEATHAS THE THIRD MOST COMMON SIDE EFFECT FROM LIBRELA.

1. The reason why the VMD refuse to add death as a side effect.

2. Why, when evidence shows that 6 dogs died during the field trials and deaths have been recorded by the VMD, do the VMD feel that pet owners do not need to know that the use of Librela could cause the death of their pets?

3. Does the VMD staff member with a spouse with shares in Zoetis have any influence on what information is released?

4. If this person does have any influence, what precautions have been taken to declare their interest and to have their work checked by an independent person ?

The update states the following:

Caution should be used when treating patients with the following pre-existing conditions: immune-mediated haemolytic anaemia, immune-mediated polyarthritis, immune-mediated thrombocytopenia. Caution should be used when treating patients with pre-existing seizure disorder

1. What research information was used which forms the basis of this statement?

2. As Librela is know to cause all the conditions listed above, please provide the research information the VMD holds to show that Librela should even be considered for dogs suffering from these conditions?

There are no safety data on the concurrent long-term use of NSAIDs and bedinvetmab in dogs. In clinical trials in humans, rapidly progressive osteoarthritis has been reported in patients receiving humanised anti-NGF monoclonal antibody therapy. The incidence of these events increased with high doses and in those human patients that received long-term (more than 90 days) non-steroidal anti-inflammatory drugs (NSAIDs) concomitantly with an anti-NGF monoclonal antibody. Dogs have no reported equivalent of human rapidly progressive osteoarthritis. No other laboratory studies on the safety of concomitant administration of this veterinary medicinal product with other veterinary medicinal products have been conducted. No interactions were observed in field studies where this veterinary medicinal product was administered concomitantly with veterinary medicinal products containing parasiticides, antimicrobials, topical antiseptics with or without corticosteroids, antihistamines and vaccines.

The field studies were not controlled, they were client owned dogs and there is zero data about what drugs were administered concomitantly with Librela, nor the resultant side effects.

1. Please explain why this very misleading paragraph has been included.

2. Please explain why no warning is mentioned that only a small number of dogs were in the field trials, 458 dogs, with a drop out rate of 1 in 8.

3. What evidence does the VMD hold to show that these 1 in 8 dogs removed before the end of the trials were not dogs suffering side effects from concomitant use of drugs and vaccines with Librela?

4. Please provide such proof.

Special warnings: This veterinary medicinal product may induce transient or persistent anti-drug antibodies. The induction of such antibodies is uncommon and may have no effect or may result in a decrease in efficacy in animals that responded to treatment previously.

1. With the information gathered from the recorded adverse effects and the information I and many others have given the VMD, namely research conducted by Professor Curtis Dewey, why are specific examples not listed as side effects?

2. Is there a member of the VMD staff suitably qualified to assess the research data and post release data especially bearing in mind that Librela is a new type of biologic drug?

3. If the answer to 2. is no, then what steps will the VMD be taking to ensure that totally independent advice is obtained in order to protect the public and their pets?

4. If the answer to 2 is yes, then please state the qualifications and experience of monoclonal antibody research that person holds.

The manufacturer has clearly stated that Librela has not been evaluated for safety with certain other medicines, including other monoclonal antibodies, vaccines, and NSAIDs, meaning interactions were not formally tested and evidence is not available.

1. Why is the VMD creating such misleading information?

2. Why, when I and many others, have given you sufficient information about this, does the VMD still persist in producing such statements?

If a vaccine(s) is to be administered at the same time as treatment with this veterinary medicinal product, the vaccine(s) should be administered at a different site to that of the veterinary medicinal products administration, to reduce any potential impact on immunogenicity of the vaccine.

What proof does the VMD hold which establishes the safety of vaccines administered at the same time or in fact any time during the use of Librela?

No interactions were observed in field studies where this veterinary medicinal product was administered concomitantly with veterinary medicinal products containing parasiticides There were no necropsy reports from the field trials in relation to assessing whether or not such an interaction would not have detrimental effects.

1. As most parasiticides are neurotoxins and Librela blocks NGF throughout the whole body, please provide the evidence the VMD has which establishes the concomitant use would not be harmful?

2. If the VMD has no such information, what action will the VMD be taking to ensure that vets and pet owners understand that the use of Librela and parasiticides is potentially dangerous?

There are no safety data on the concurrent long-term use of NSAIDs and bedinvetmab in dogs. In clinical trials in humans, rapidly progressive osteoarthritis has been reported in patients receiving humanised anti-NGF monoclonal antibody therapy. The incidence of these events increased with high doses and in those human patients that received long-term (more than 90 days) non-steroidal anti-inflammatory drugs (NSAIDs) concomitantly with an anti-NGF monoclonal antibody. Dogs have no reported equivalent of human rapidly progressive osteoarthritis.

The VMD have confirmed at least 17 reported cases of rapidly progressing osteoarthritis relating to LIbrela. The peer reviewed Farrell report highlights this.

1. Why is the VMD ignoring such important information from such a highly respected source?

2. What steps have the VMD taken to amend records/ adverse event reporting forms to include RPOA on the list of side effects?

3. If the VMD have not taken steps to include RPOA as a side effect, what is the reason for this.

No adverse reactions, except mild reactions at the injection site, were observed in a laboratory overdose study when the veterinary medicinal product was administered for 7 consecutive monthly doses at 10 times the maximum recommended dose.

1. Why does the VMD specify this in view of it being a very misleading statement in relation to the Librela target market, i.e., older dogs with osteoarthritis?

2. The necropsy reports on the 32 lab trial Beagles (18 months old at time of necropsy) after 6 monthly Librela injections AT THE NORMAL DOSE show some horrific findings such as mononeuclear infiltrate in brain, tongue, thyroid, oesophagus, liver, salivary glands, kidneys + rectum, focal gliosis on spinal cord, proteoglycan depletion, cartilage necrosis. plaque in spleen, misshapen spleen, pituitary + vaginal cyst + much, much more.

In view of such findings, on what basis did the VMD form this statement?

In case of adverse clinical signs after an overdose the dog should be treated symptomatically

1. Please explain how dogs are expected to be safely treated when Librela has not been tested with any other drugs?

2. Exactly what drugs does the VMD suggest using? Please validate this statement.

3. This vague ‘information’ is leaving pet owners and vets at a huge disadvantage. Why does the VMD think this is acceptable?

The importance of nerve growth factor (NGF) in ensuring normal foetal nervous system development is well-established and laboratory studies conducted on nonhuman primates with human anti-NGF antibodies have shown evidence of reproductive and developmental toxicity. Pregnant women, women trying to conceive and breastfeeding women should take extreme care to avoid accidental self-injection.

This study also exposed that Librela reduced the size and number of postganglionic cells. Once the number of postganglionic cells is reduced, they are unlikely to increase. This can lead to loss of neurons in the autonomic nervous system - the system that controls automatic body functions which has an effect on most of the body, brain, bones, heart, respiratory system, eyes, gastrointestinal system, bladder, bladder control, blood pressure etc, NOT ONLY THE REPRODUCTIVE ORGANS + EFFECTON THE FOETUS.

1. What action is the VMD taking to establish links between the side effects being recorded are not a result of reduced numbers of postganglionic cells as well as the effects of Librela blocking NGF?

2. When the VMD is quoting such things, do they investigate the information and check for accuracy and verification from trial information?

It is very obvious that UK veterinarians are not recognising all the many side effects of Librela. This has been brought to the attention of the VMD on many occasions.

1. Why have the VMD failed to compose a comprehensive list of side effects as the US FDA has?

2. In view of Librela being a new type of biologic drug, why does the VMD feel it isn’t necessary to provide detailed information to vets and the public?

3. Where does the VMD expect vets to get such information from?

4. Does the VMD expect every vet in the UK to submit a FOI request in order to gain knowledge of the side effects from Librela?

Our reply

Your request includes a significant number of individual questions covering a wide range of topics. To assist you, we have provided general information about our regulatory role, the authorisation process, and where relevant, links to material that is already publicly available.

If there are specific pieces of recorded information you would like us to consider, please let us know and we will be happy to assist you in refining your request. This helps ensure that we can respond proportionately and provide meaningful information.

For questions relating to the approval process and supporting documentation:

Librela was originally authorised via the European Centralised procedure which is a unified authorisation route overseen by the European Medicines Agency (EMA). It results in a single Marketing Authorisation (MA) valid across all EU Member States and EEA countries. See also Authorisation of medicines European Medicines Agency (EMA).

We do not hold a recorded explanation setting out the detailed reasoning for these specific decisions because at the time decisions of this nature were taken in line with established regulatory processes rather than documented individual rationales.

When the UK left the EU, Northern Ireland remained in the EU regime and Great Britain transitioned to the national Veterinary Medicines Regulations. In January 2021, the VMD automatically converted existing marketing authorisations for Centralised products to GB authorisations.

For questions relating to post-authorisation monitoring:

Once a product is on the market there is a process of surveillance in place to monitor its continued positive benefit/risk balance; this is known as pharmacovigilance. This activity is undertaken, independently, by both the VMD and the Marketing Authorisation Holder (MAH).

In response to a previous request, FOI2025/00333, we have explained many of the questions you pose. This is not yet published so for convenience we have attached a copy of that response.

Advice and assistance:

If you consider that specific recorded information has not been provided, you may submit a new request clearly identifying the documents, records or categories of information you believe are held by the VMD and have not been addressed.

Clearly defining the recorded information sought will enable us to assess whether it is held and to consider the request in accordance with our obligations under the Freedom of Information Act.

FOI2025/00333 response