I was wondering where you got that 25-30% figure....interesting, and quite a variance from other articles I'm seeing.  Here's a paper that includeds a table that shows the success rate of Phase III to NDA being 65% for immunologic indications and 58% for all indications, and then 89% and 85% respectively for NDA to Approval.  

https://www.jacionline.org/article/S0091-6749(17)30753-4/pdf

I wonder if that 25-30% figure is for moving onto a further Phase 4 study instead of going to NDA.