Ethnic Factors and Bridging Requirements

Historically, methods of clinical testing differed in various regions, resulting in lengthy delays in global drug approval. Various populations suffered from significant lags (primarily Japan), which pushed global health organizations to integrate a new method of extrapolation from region to region. In an effort to minimize the duplication of data and expedite global drug development, the trend toward Ethnic Bridging began.

In 1998, ICH E5 established efficacy guidelines to characterize the requirements for Ethnic Bridging, which they defined as: “A study performed in the new region to provide pharmacodynamic or clinical data on efficacy, safety, dosage and dose regimen in the new region that will allow extrapolation of the foreign clinical data to the population in the new region.”

Additionally, ICH E5 suggested a thorough 3-step process for evaluating the acceptability of foreign clinical data. This begins with a primary assessment of the completeness of the clinical data package, and a determination as to whether or not the initial drug properties have been accurately assessed.

Next, there is an assessment of the product’s sensitivity to ethnic factors. This includes analysis of: PK/PD factors (safety, tolerance, efficacy, dose responses), extrinsic factors such as food, climate, and other cultural or behavioral aspects, and intrinsic factors such as genetics.

In the final step, having extensively evaluated whether or not extrinsic factors can affect the drug’s safety, a determination is made as to whether Ethnic Bridging is necessary, and whether data can be extrapolated to the desired region. In some instances, if the drug is not ethnically sensitive, or if two populations possess intrinsic similarities backed by previous clinical data, bridging is not necessary.

Once these steps have been performed and bridging is deemed necessary, WCCT works directly with the Sponsor to create a tailored development plan based on the specific drug’s properties and the trial objectives. In the next Ethnic Bridging post, we’ll explore additional factors that help WCCT collaborate with developers to implement bridging studies that help expedite drug development worldwide.