Impact of exposure accrual on sequential postmarket evaluations: a simulation study

Area of Science:

• Pharmacovigilance and Drug Safety
• Biostatistics
• Health Outcomes Research

Background:

• Sequential database surveillance (SDS) is crucial for postmarket drug safety.
• Understanding challenges like exposure accrual is vital for effective SDS implementation.
• The US Food and Drug Administration's Sentinel System relies on robust surveillance methods.

Purpose of the Study:

• To analyze challenges in sequential database surveillance (SDS) studies.
• To illustrate exposure accrual using simulation techniques.
• To inform the planning of postmarket surveillance strategies for regulatory authorities.

Main Methods:

• Utilized US Medicaid data for new molecular entities approved in 2005-2006.
• Traced exposure accrual to assess person-time.
• Simulated risk estimates by varying health outcome of interest (HOI) event rates.

Main Results:

• SDS can narrow risk estimates within 2 years for common HOIs (≥1/100 person-years).
• Exposure accrual is insufficient for detecting risks with infrequent HOIs (<1/1000 person-years).
• Most products are viable SDS candidates for detecting incremental risk differences.

Conclusions:

• SDS performance varies based on regulatory goals: narrowing risk estimates versus confirming/ruling out excess risk.
• Viability of SDS depends on desired endpoints, available exposures, and HOI rates.
• A decision-analytic framework can aid regulatory planning for postmarket surveillance.