**4.2 DDI evaluation**

Based on the results of the P450 inhibition/induction assays and the screening DDI studies, specific P450 isoforms are further investigated *in vitro* for the DDI potential instead of a general cocktail approach as employed in the Lead Optimization stage. If an *in vitro* DDI is observed, an *in vivo* study is warranted to confirm if the DDI persists.
