Consistency assessment with global and bridging development strategies in emerging markets

Global trial strategy with the participation of all major regions including countries from emerging markets surely increases new drug development efficiency. Nevertheless, there are circumstances in which some countries in emerging markets cannot join the original global trial. To evaluate the extrapolability of the original trial results to a new country, a bridging trial in the country has to be conducted. In this paper, we first evaluate the efficiency loss of the bridging trial strategy compared to that of the global trial strategy as a function of between-study variability from consistency assessment perspective. The provided evidence should encourage countries in emerging markets to make a greater effort to participate in the original global trial. We then discuss sample size requirement for desired assurance probability for consistency assessment based on various approaches for both global and bridging trial strategies. Examples are presented for numerical demonstration and comparisons.