rGBM is a tough nut to crack. Not many will invest in VB-111 because of this, and short sellers will sell based on this statistic. The odds are HEAVILY stacked against VB-111 being successful (in extending OS). If prior drugs have had success against rGBM then I think you'd see the stock at around $10-15 based on potential.
If VB-111 is effective, it'll be the first one to claim that it can improve survival.
Even avastin cannot claim this - "Currently, no data have shown whether or not Avastin improves disease-related symptoms or survival in people with rGBM."
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