Biotech Values

[iwfal]

that said low or absent incidence of flare in the exel data is more a curiosity rather than something that makes me question the treatment response since it is something that leads to false positives but not false negatives (i.e. some responders have worsening bone scans initially, but few non-responders have improving bone scans)

My overarching thesis is that the community hasn't really characterized bone scan data. And without that data it is impossible to know what the data means in a clinical sense.

As for the XL data being different from the limited data seen before - no flare seen - that seems worrisome to me because:

a) Different is generally bad in a clinical trial

b) It goes against what you'd expect for healing bone.

PS Agree that part of the problem with making any historical comparisons is the different protocols. E.g. different durations between bone scans. Or different interpretations of those scans.

PPS See figure 9 in the below cite for a case where they used CT Scan with a bone scan to try to differentiate whether the bone scan flare was due to healing or progression. At least in that case it appears it was healing. Many months after start of treatment. As you point out the flare phenomenon is actually pretty well documented and is a large part of the reason that I am suspicious that there is something else going on in the XL184 scans.

http://www.jcancer.org/v01p0080.htm