Question to the Home Office:

To ask the Secretary of State for the Home Department, what plans she has for the lethal dose 50 test.

The UK continues to lead the way in seeking the adoption internationally of improved testing methods that replace, reduce or refine the use of animals in scientific procedures.

Some authorised medicines in the UK include quality control tests which require the use of animals, conducted to ensure the quality, safety, and efficacy of specific medicines. These tests account for the LD50 cases still conducted.

UK regulators follow the principles of the 3Rs – to replace, reduce and refine the use of animals in tests. Significant progress has been made on validating alternative methods which do not use animals, including the possibility of replacing mice by in vitro suitable cell cultures in LD50-type testing methods, and the relevant regulatory quality standards and testing requirements have been revised accordingly for these specific medicines.

The implementation of new tests for existing products must be a process that protects and prioritises human safety, often requiring extensive validation. It is not presently possible to replace all of the existing animal tests with in vitro non-animal replacements.