The Bayesian early-phase seamless transformation (BEST) platform provides a fast, efficient, and powerful solution for early-phase drug development. It’s based on a framework of seamless dose findings, cohort expansion and proof-of-concept (POC) scheme. The entire platform offers a suite of innovative and efficient Bayesian adaptive designs for different objectives. Due to the novel Bayesian methods, the BEST platform can improve the overall study power in selecting the promising doses and indications for late-stage drug development and eliminate toxic or inefficacious doses quickly without wasting resources. This leads to increased probability of success for drug development as a whole, accelerated development process and reduced costs for sponsors.