 This report summarizes the proceedings for day two sessions one and three of the two-day public workshop entitled Regulatory Utility of Mechanistic Modeling to Support Alternative Bioequivalence Approaches, which was jointly sponsored by the U.S. Food and Drug Administration, FDA, and the Center for Research on Complex Generics, CRCG. Day two focused on the topic of oral PBPK as an alternative bioequivalence approach and its potential use in supporting risk assessments and bio waivers. Presentations included current status of oral PBPK, case examples, and challenges and opportunities in this area. Additionally, panel discussions on the utility of oral PBPK in both new drugs and generic drugs from regulatory and industry perspectives were summarized. This article is authored by Feng Wu, Yousef Musa, Kimberly Reigns, and others.