Findings
PRO instruments must demonstrate content validity through patient input and qualitative research, ensuring the instrument measures concepts relevant to the population and condition being studied.
Sponsors must confirm the reliability, construct validity, and ability to detect change for the PRO instrument before use in confirmatory clinical trials.
Statistical analysis plans should address multiplicity, handling of missing data, and cumulative distribution function comparisons to interpret clinical trial results.
Modifications to PRO instruments (e.g., format changes, population adaptations) require evidence that measurement properties are preserved.
Electronic PRO systems must comply with regulatory requirements for data integrity, security, and investigator access.

Recommendations
Develop and validate PRO instruments early in the clinical development process, ensuring alignment with the clinical trial’s endpoint model.
Document all stages of instrument development, including qualitative input from patients, pilot testing, and cognitive interviews.
Use clear and consistent administration procedures, whether paper-based or electronic, to minimize variability and missing data.
Define responder thresholds using anchor-based methods and consider presenting cumulative distribution functions to interpret treatment benefits.
Address cultural and linguistic adaptation of PRO instruments by ensuring equivalent content validity and measurement properties across versions.

Regulatory Considerations
Include detailed descriptions of the PRO instrument, its conceptual framework, and scoring algorithms in regulatory submissions.
Ensure PRO instruments used in clinical trials comply with FDA requirements for record-keeping, data security, and source data accessibility.
Plan for the FDA to review all modifications to PRO instruments, including changes in administration mode or population.
Address missing data in clinical trial protocols and statistical analysis plans, ensuring prespecified handling rules.
Provide evidence that PRO instruments reliably measure the intended concepts across all study populations and data collection methods.