"Since the 2012 passage of the FDA Safety and Innovation Act (FDASIA), FDA has also been able to use a fourth expedited program known as breakthrough product designation.
As defined by FDA, breakthrough product designation is intended for products that treat a serious condition based on preliminary clinical evidence that indicates the drug may demonstrate substantial improvement on clinically significant endpoints over available therapies.
In other words, no "me-too" drugs – the breakthrough designation is meant for first-in-class treatments or ones targeting diseases in ways that no other drug has before.
Unlike the other designations or pathways, breakthrough product designation isn't meant to expedite development based on shortened timelines or surrogate markers, but rather grant access to enhanced review tools such as all of the features of the fast track designation, as well as "intensive guidance" from FDA regarding the development of the product.
As with the other two types of designations, FDA may withdraw breakthrough status if the product no longer meets the qualifying criteria for the designation."
Pay particular attention to "no 'me too' drugs" - I would assume that means once we get AA, GSK's BTD is null and void?!?! Anyone know how this works? Would appreciate any thoughtful responses.
The BTD is a non-issue at this point. SRPT will likely file for AA by year-end 2013 (or early 2014 at the latest) and with priority review will have a decision by Q2 2014. Prosensa is not done with their Phase III trial until Q4 2013, so they won't be in a position to file until Q2 2014. As you pointed the benefit of BTD is better access to the FDA - with both programs being late in the game, it doesn't give them an edge at this stage. By year-end, all the warts of Prosensa's drug will be known - as a public company they will have to disclose all the dirty details about the safety issues and all the stats on dystrophin production. Assuming what we know now holds up - i.e. SRPT has a safer drug that is able to be delivered in higher doses in a more consistent fashion, likely leading to better dystrophin levels - then BTD will be meaningless. Even if by some fluke they get approval around the same time as SRPT, what parent is going to want to take a chance on Prosensa, when Eteplirsen has a spotless safety record?
Not correct. Recent guidance by FDA confirms that because AA drugs are subject to further ongoing evaluation they do not constititute an available therapy and do not disqualify breakthrough desination. See FDA June 2013 industry guidance.