Avid Bioservices Inc (CDMO)

[BioBS2012]

In other words, OS might be extended from 6 months to 8 months, which might attain statistical significance, but is not a marketable difference in treatment.

Personally, I would be very interested to see how the OS data compares with the Nivolumab data versus Docetaxel.
http://www.nejm.org/doi/full/10.1056/NEJMoa1507643#t=abstract
Also of interest is the late-breaking abstract for Phase III data from Roche/Genetech's Atezolizumab versus docetaxel, which is being presented at ESMO a day earlier. For reference, here are the Phase II #'s
Overall survival in the intention-to-treat population was 12·6 months (95% CI 9·7–16·4) for atezolizumab versus 9·7 months (8·6–12·0) for docetaxel (hazard ratio [HR] 0·73 [95% CI 0·53–0·99]; p=0·04).
http://www.thelancet.com/pdfs/journals/lancet/PIIS0140-6736(16)00587-0.pdf

As far as a biomarker, is it something detectable by a blood test, or will it require biopy of the tumor during treatment?

Given that they mentioned having collected 1000's of samples from SUNRISE alone, one can surmise that this biomarker is detectable by a blood test. IMO.

Cheers.