NorthWest Biotherapeutics Inc (NWBO)

[Umibe5690]

My views on PFS are quite simplistic. PFS is used as a surrogate for the gold standard, OS. Obviously long tail(and its composition) is the most important part of OS alongside milestone markers. When you have actual data, you do not need to rely upon the surrogate which is employed as a way to shorten the trial. However, in immunological approaches, PFS may not correlate well with OS.

Further, it is within the realm of possibility that although there may be earlier PFS eventing, this is not necessarily a bad thing. Due to the way immunological approaches may work, as the therapy begins to take hold in time, progression rates may be slowed and perhaps reduced to zero thus contributing to increased OS. What would be interesting to see is a comparison of the deltas between PFS and OS eventing. JMHO.