Guidance

Post-authorisation safety studies

Updated 8 June 2022

Applies to England, Scotland and Wales

1. What is a post-authorisation safety study (PASS)

A post authorisation safety study is any safety study carried out after a medicine has been authorised. The aim is to:

  • identify, characterise or quantify a safety hazard
  • confirm the safety profile of a medicine
  • measure the effectiveness of risk-management measures

These studies can take the form of non-interventional studies, in which a medicine is prescribed in the usual manner in accordance with the marketing authorisation.

2. Why is a PASS needed

Before authorisation, the number of animals exposed to the veterinary medicine is restricted, so experience of adverse events within any specific population of the target species may be limited. Post-authorisation, the number of animals exposed becomes greater, and can reveal other safety issues that were not apparent during the pre-authorisation stage.

An MAH may elect to carry out a PASS to investigate whether:

  • the concurrent use of a specific product with another specific product results in previously unknown adverse events
  • the use of a specific product in a particular breed of animal results in previously unknown adverse events
  • the incidence of a particular adverse event is dependent on the age of the animals treated with a specific product
  • the incidence of a particular adverse event is dependent on the existence of another underlying disorder
  • long term use of a product gives rise to an adverse event

There may be many reasons for the need for a PASS. The VMD may require an MAH to carry out such a study, if they determine that there may be evidence of something that needs further investigation.

3. How is a PASS carried out

Only animals treated with a particular medicine in the manner specified in the SPC can be included in a PASS. The MAH may recruit animals that fit the criteria for the study to be performed. Once recruited, the animal will be treated as it would normally be treated for the condition it has, but the vet providing that treatment will be required to monitor the animal more closely, throughout the treatment.

4. What happens after the study

At the end of the study, the MAH will provide the VMD with the findings, which will determine whether there is or is not evidence of any ill effect. As a result of this, the VMD may require the MAH to update the product literature to, for example:

  • exclude the use of the product in a particular age-range or group of animals
  • perform closer monitoring of animals in a particular age-range or group of animals
  • advise that the product is not used at the same time as another

5. What types of studies are not included

Clinical trials in which a medicine is used in a manner not authorised for the species in question.