Bridging studies

Bridging studies

According to ICH E5 guidelines, a bridging study on a medicine can be defined as an additional study executed in a new geographical region to "build a bridge" with foreign clinical data on safety, efficacy, and dose response. This ‘bridging’ of clinical studies is usually made by extrapolating the foreign clinical trial data to the population in the new region. 

In other words, a bridging study is a supplementary study on a particular medicine that is performed in the new region. It is carried out in order to relate the information available from previously completed tests and any questions from the regulatory authority on account of ethnic factors. Bridging studies, conducted to assess the efficacy of new drugs, could provide additional drug response data in the population of the new region (

In principle, this definition means that essential pivotal phase III studies organized by a non-European company must be repeated in a Caucasian population if the original studies have been done with non-Caucasian subjects only. The pharmacokinetic phase I studies on very well-known molecules from European Pharmacopeia may be accepted by regulatory agencies. In all other cases, proof of efficacy, safety and dose must be shown through a bioequivalence phase III bridging study. In more specific terms the bridging study usually has around 30 - 40% of the original patients from the pivotal study, which in generic products means about 200 – 300 subjects. In original studies this number is necessarily higher and reflects specific indications. The average duration of an entire generic bridging study is around 12 – 14 months from protocol preparation to the completion of the final report.

Accord Research has extensive experience of organising and executing these types of bridging studies for Asian pharmaceutical companies (Japan, South Korea, China).

Accord Research organises these bridging studies mainly in the region of Central and Eastern Europe, which ensures a competitive cost implications and the swift enrolment of the required number of patients.