Phase 2 results OGXI reported at ASCO this year for OGX-427
I think they are likely much too late to the party as monotherapy. For combo therapy in patients refractory to Xtandi/Zytiga (where the expense would be a real issue), I suppose it might be interesting, but so would other combinations (like a PI3k inhibitor).
For that matter the Exelixis drug shows pretty decent activity in patients that have failed Xtandi/Zytiga.