In GCP, how are efficacy data distinguished from safety data?

• A. They are synonymous
• B. Efficacy data pertain to treatment effect
• C. Efficacy data relate to adverse effects and risks
• D. Safety data only relate to lab results

Answer: (B)

In GCP, data are distinguished by what they measure: efficacy data assess the treatment’s effect, while safety data focus on potential harms. Efficacy data come from endpoints that show whether the investigational product produces the intended therapeutic benefit—such as improvements in clinical outcomes, symptom relief, biomarker changes, or survival. Safety data, on the other hand, monitor adverse effects and risks associated with the product, including adverse events, serious adverse events, lab abnormalities, and other clinical observations that inform tolerability and risk. The statement that efficacy data pertain to treatment effect is the best description, while the other options mix up the roles of efficacy and safety or restrict safety to only lab results.