Insofar as metastatic prostate cancer is terminal and a large proportion of the deaths come from skeletal events and their complications (such as VTE), the boundary between treating the cancer and treating/preventing the bone mets is not well defined, IMO.
It clearly doesn't sound like the boundary is well-defined. One of the callers tried to bridge the gap by asking the doctor if any of the previously approved disease modifying drugs for HRPC showed a correlation between an improvement in bone scans and survival. There was a bit of a pause but I believe the doctor indicated that the disease-modifying drugs have never shown improvements in bone scans.
The best I can gather from listening to the calls is that the company and investigator are indicating that a HRPC patient will most of the time die due to bone metastases. But, in the absence of bone metastases (presumably due to a bone-targeted drug like denosumab), the HRPC patient will still die from the soft tissue cancer. And EXEL is hoping that 184 will be effective in both instances.
I listened shortly after the call so my memory may be fading.
But I seem to recall the investigator saying that no agent up to now has shown activity in BOTH the soft tumors and the bone mets.
XL184 reduced pain (a critical problem) and appears (dramatic changes in the slides) to be reversing bone mets (skeletal failure is the main cause of death in fast moving PC).
The results were not semantics even if trial design was.
PC is the #2 cancer-killer of males (behind lung cancer). There are around 70K new cases per year of the fast moving variety. This is a big unmet medical need.