First-in-human phase I Oncology studies have used the following two approaches for dose escalation widely; A modified continual reassessment method (mCRM) and Accelerated Titration Method (ATM). There was consensus on the need of making informed decision for the dose escalation. For mCRM, specifically, two-parameter Bayesian logistic regression model with escalation with over dose control principle was considered to incorporate the pre-clinical data and knowledge of very low chance of DLT at the starting dose. For ATM, the criteria to trigger the “3+3” phase was lower than standard ones since the biologically effective dose is expected to be lower than a MTD. The familiarity and simplicity of implementation of ATM and the accuracy and flexibility of mCRM were discussed during the study development with the disadvantage of each approach; under-estimation of MTD and rigidity of ATM and added operational complexity as well as up-front statistical planning and extensive simulation of mCRM. The pros and cons of each design as well as the concerns of both clinical and statistical perspective during the study development will be discussed.