Before I go out for the day, I wanted to be clear on what I was speculating about with regard to OS and AA. First, I referenced Dr. G's continued stressing of the role OS should play in any AA consideration. In a past cc, he even mentioned that it is often the case that an outcome observed with a surrogate doesn't translate into the clinical benefit being sought (i.e. PFS may not translate into OS, and I seem to recall that I read that was fairly evident with TNBC, but I don't have time to search for that now.)
Second, I observed that the maturing OS data in the first stage of the phII could offer valuable input with regard to how PFS correlates with OS, and that may be exactly what is needed to satisfy the FDA that the SPA granted for the ph3 is grounded in good science, AND, to satisfy a partner that the confirmatory trial using PFS as the primary endpoint will pan out. Finally, it may strengthen the AA filing since any observed clinical benefit supports the use of the surrogate if, in fact, the surrogate correlates positively with that benefit. And don't forget, the OS data for the first cohort should be quite mature by the proposed filing for AA, which was stated to be mid-2017. This is all different than stating that OS will be used as the primary endpoint in the ph2. Maybe you misinterpreted my point.
I also copied and pasted snippets from various FDA guidance documents, one of which makes it evident that an SPA isn't necessarily an irrevocable contract. The other goes into the importance of establishing a correlation between the surrogate and clinical benefit.
Much of the information I employ in offering some degree of support to what I have admitted to be utter conjecture, comes from years of conversations about this stuff with the company, including more recent discussions with Chau on such subjects as the Simon Two-Stage Analysis, endpoints, and such. I may have even introduced this board to some of these things, including the requirement of a surrogate or intermediate endpoint in pursuit of AA.
Your response, Li, takes one part of one statement that Dr G voiced in a conference call, which I referenced in the post at issue, and stated that with regard to the discussion, it had "gone off in the wrong direction." What I was trying to do was speculate on Dr G's fixation on OS with regard to an AA filing. I hope the above clarifies my point.
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