Detailed Explanation
Database lock represents a critical milestone in clinical trial conduct, signifying that all protocol-required data have been collected and entered, all queries have been resolved, all data cleaning activities have been completed, and the data are ready for statistical analysis. After lock, the database becomes read-only and no further modifications are permitted without formal unlock procedures, ensuring that the data analyzed and reported are stable and verifiable. The locked database serves as the foundation for all efficacy and safety analyses and ultimately supports regulatory submissions.