Applications of personalized medicine are becoming increasingly prominent. A well-characterized companion diagnostic assay (CDx) is often desired for patient enrollment in device-drug pivotal clini- cal trial(s) so that FDA can ensure that appropriate clinical and analytical validation studies are planned and carried out for CDx. However, such a requirement may be difficult or impractical to accomplish. A clinical trial assay (CTA) instead of CDx may be used for full or partial patient enrollment in drug-device piv- otal clinical trial(s). A supplemental agreement study of CDx and CTA will be required to bridge the clinical results from CTA to CDx. In this paper, we will discuss statistical challenges in study design and data analysis for bridging study. Particularly, we aimed to provide statistical methods on how to estimate the drug efficacy in CDx intended use population using results from bridging study and CTA-drug pivotal clinical trial.