Well...this is such a unique trial type. We see the safety endpoints being met, and we see what appears to be an increased rate of decline in first post surgical year for nonresponders. This, if it is real, would create need for further review as the existence of increased rate of decline may have to be assessed outside of the monitoring window of time given for the trial. It would be a serious safety concern - just one that didn't emerge to be adequately measured during the life of the trial. The FDA will require this risk proven or disproven. And - if company can prove tight quantitative criteria measurement of responder pool, thus eliminating such risk (if it truly exists) to nonresponder - the FDA unlikely to halt. Still, there is this question of an unanticipated longer term risk that needs to be addressed and quantified. I imagine many investors have their investment $ on the sidelines as they wait for the full trial write up to explain this surprising grey area.