NorthWest Biotherapeutics Inc (NWBO)

[Dan88]

There are numerous examples of p4 confirmation trials. Just google it you will see some at least. Basically, when a company gets AA or the like, it has to run a successful p4 confirmation trial in order to get full approval. Nonetheless, since the company can market and sell the approved product (AA), it is usually the case that most of such companies would be reluctant to start and complete a p4 confirmation trial required for full approval. One other problem is that because the product is an approved commercial product, it is difficult for the company to get enrolment done. Of course there are about 15% approved products statistically get pulled out from market after a failed p4 trial.

So it seems that FDA nowadays is more inclined to allow a trail to serve the purpose of both AA and confirmation, kind of combining "two trials" into one integrated trial.

That's why a company has to be very careful not to compromise in anyway of the existing pivotal trial in the event of a stop for efficacy recommendation from DMC based on IA. So there are certainly uncertainties, secrecy and confusions coming with it.