Finally, even if there is a flare the FDA is clearly willing to allow for protocols that try and eliminate this for purposes of progression adjudication.
I think there is some confusion here. Drugs like paclitaxel help some with bone mets but often cause an initial flare that then resolves at the next scan. So an initial flare is not considered evidence of progression.
For the EXEL drug, the question has been raided why there isn't a temporary flare if the lesions are in fact healing. I don't think anyone yet has a good answer to this - all we know for sure that there is no significant osteoblastic activity. There could still be osteolytic activity or there could be non-progression or even slow healing of the lesions.