TABLE 1.

Limits of Existing Methods of Post-Marketing Surveillance

Long-Term Extensions of Clinical Trials	Passive Adverse Event Surveillancea	Single-Product Phase IV Registries
Small sample size	Limited or incomplete clinical information	Challenging recruitment leads to inability to reach enrollment targets
Restrictive eligibility requirements	Underreporting and other reporting biases	Retention issues lead to small numbers of exposed patients by the end of study
Excludes patients with comorbidities	No method to determine total number of exposed patients	Multiple competing JIA patient registries unsustainable
Randomized withdrawal clinical trial design	Comparator group information is often unobtainable
Limit placebo exposure (no comparator group)
Selection bias: eliminates nonresponder patients and patients with adverse events

^aThe FDA Sentinel System has been implemented to augment the passive surveillance systems by actively querying multiple data systems, such as public and private payers and pharmacy databases.