The primary objective of original RFA-FD-14-011 (subtopic 2) is to develop pharmacometric modeling and simulation tools for generic drug substitutability evaluation and post marketing risk assessment. The goal is to develop pharmacometic approaches (including clinical trial simulation and clinical use/substitution simulation) that will aid OGD in the evaluation of post-market risk and the interpretation of post-market adverse event reports or product substitution complaints. The scope of the awarded study is being expanded to risk-based methodology on generic equivalents of the reference list drugs (RLDs) that may be most susceptible to â₏œwith causeâ₏ switching issues (e.g., modified release oral dosage formsâ₏ or â₏œpatient perceptionâ₏ of switching issues where differences in efficacy or safety can be readily perceived in clinical practice (e.g., anticoagulants). The risk-based methodology will be applied to predict which generic product is most likely to encounter switching issues, and least likely to demonstrate post-marketing bioinequivalence.