Since 2008 FDA guidance for T2DM drug development, CV safety outcome studies have been conducted for all newly developed T2DM drugs. The studies and development programs various with significant amount of statistical considerations including population selections, study designs, endpoint selections as well as method of statistical evaluation. Specifically, the new challenges in statistical methodology including statistical testing methodology and type I error control, and data analysis methodologies focusing on ITT analysis especially on general safety. Specifically, the testing procedures and data interpretation involving both non-inferiority and superiority for the primary and important secondary endpoints various from study to study. In addition, the data included and the method of general safety analysis in such a CV outcome study also post a challenge. An ITT principle based safeness evaluation is considered more appropriate than a traditional on treatment analysis based on pharmacology effect for safety data evaluation for CV outcome studies, in addition to the general ITT principle for primary CV outcome evaluation.