When a medicinal product is approved for marketing, demonstration of safety and efficacy are generally based on data from a limited number of patients, with many studied under the controlled conditions of randomized trials. Higher risk subgroups and patients with concomitant illnesses that require use of other drugs are often excluded from clinical trials, and long-term treatment data is limited. Moreover, patients in trials are closely monitored for evidence of adverse events.
In clinical practice, monitoring is less intensive, a broader range of patients are treated (age, co-morbidities, drugs, genetic abnormalities, and so on), and events too rare to occur in clinical trials (such as severe liver injury) may be observed. These factors underlie the need for continuing analysis of relevant safety, efficacy, and effectiveness information throughout the lifecycle of a medicinal product promptly and periodically, for an overall assessment of the accumulating data.
The PSUR provides a comprehensive picture of the safety of approved medicinal products, as the assessment of the risk of a medicinal product is most meaningful when considered in light of its benefits. The PBRER provides greater emphasis on benefits, particularly when risk estimates change, and places greater emphasis on the cumulative knowledge regarding a medicinal product, while retaining a focus on new information.