What are 'endpoints' in the context of humane animal research?

• A. Predefined criteria for terminating the study to prevent or minimize pain or distress.
• B. A final data point in a study.
• C. A time-based milestone.
• D. The end of the grant funding period.

Answer: (A)

Endpoints are predefined criteria used to decide when to terminate an experiment or intervene to prevent or minimize pain or distress in the animals. They are set before the study begins and reflect signs of suffering or health decline that require action to protect welfare. When an endpoint is reached, the animal is typically humanely euthanized or given relief, ensuring the study respects animal well-being. This focus on stopping harm distinguishes endpoints from other concepts like a final data point, a simple time-based milestone, or the end of funding, which relate to data collection, scheduling, or administration rather than animal welfare.