Fda guidance for DMD drugs

https://www.fda.gov/media/92233/download

This is the current FDA guidance on Duchennes drugs

Some key points

* MRI is acceptable as a biomarker

* some toxicity is acceptable due to the high morbidity associated with DMD

* randomised controlled trials are ideal however comparison with historical controls are acceptable for approval provided a large effect size is seen in treatment group ( this what the Rome cohort analysis is targeting)
* efficacy results for 3 months are sufficient, safety results for 1 year are also sufficient for approval generally, less safety data is required if strong efficacy is shown

* data from a small subgroup can support approval for a large indication

Basically the FDA is pretty lax when approving DMD drugs and any hint of reasonable efficacy and safety will allow an expedited approval.