Joe has given previously stated why they didn't pursue an SPA for the anemia indication in one of the CC's. I would have to review the details, but I think your on the right tract. It came down to a risk vs benefit decision.
BTW, I am not being particularly critical of RPRX (just questioning). And I do kind of follow dewo's view on the drug proper (I believe he is very honest wrt the value of a drug that delivers the clinical benifit Prol. is looking at).
I just sometimes get tired of the happy face stuff.