I don't really think your points are valid. There is clearly no significant titration issue - no SAEs, and excellent across-the-board efficacy of 45% reduction in progression over placebo over 48 weeks.
FDA wants to see definitive dose dependent efficacy
Dose-dependent responses can be seen at lower dosages. It doesn't have to be 50mg for some. The genetic data will substantiate this fact for the FDA. This is the "precision medicine" aspect...