Sarepta has always had the "promise" of successful products - yet has historically had poor follow through on any confirmatory trials. The exon skipping products which supports the company's lavish lifestyle were approved with the promise of quickly following confirmatory trials. To my knowledge that still hasn't happened for the conditional approval of eteplirsen from 2016. Just googled it and this was the paragraph that came up "Eteplirsen, golodirsen, and viltolarsen were approved based on the demonstration of increases in truncated dystrophin protein the clinical benefit of these dystrophin changes are being evaluated in confirmatory studies."
This is from their current 10-Q under management discussion: "our ability to timely comply with FDA post-marketing requirements and commitments, including through successfully conducting additional studies that confirm clinical efficacy, effectiveness and safety of our products and acceptance of the same by the FDA and medical community since continued approval may be contingent upon verification of a clinical benefit in confirmatory trials, particularly in light of FDA's expanded expedited withdrawal procedures as set forth in FDORA"
Eteplirsen was approved in 2016.
The company has always been rich in promises.