Biotech Values

[DewDiligence]

>>DNDN -- Q for Dew or Others<<

I read all the posts you cited. They lay out the arguments pretty well, so there’s no need to say much here.

However, I think the posts in question missed one important point about the value of the TTP endpoint, or lack thereof.

In disease settings where patients can be expected to live a long time, TTP (and its analog endpoints of PFS and DFS) is an endpoint with considerable value in its own right. In these situation, overall survival takes an eternity to measure and it is therefore subject to considerable variation from factors other than the therapy being tested.

On the other hand, in cases where most patients can be expected to die within a few years, TTP has much less usefulness as an endpoint. When overall survival is itself measurable in these situations, TTP becomes close to meaningless as it is merely a surrogate for something (overall survival) that no longer needs a proxy.

The above two paragraphs can be considered the two poles for the relevance of TTP. The case of DNDN’s Provenge is much closer to the second pole than the first one, and hence I think TTP has little standalone importance in the 9901 and 9902a trials.

That said, the FDA could take a hard-nosed position and say that, hey, TTP was the primary endpoint when this trial was designed and it stays the primary endpoint… sorry. This is why my thesis for owning DNDN has been that the 9902b trial might still be needed to support a BLA. I am less convinced than other longs that 9901+9902a will suffice for a BLA, although I think the probability is about 65% that they will.