Jelly - Most likely the blood brain barrier is disrupted by the tumor or it does not get past the BBB, and the positive results seen by nimo are the result of vegf properties.
They have tagged nimo with a radio and did scans so we do know that in some cases it is getting past the BBB. In all cases? YMI has these slides if you want to see them. The computer I had them on crashed so I no longer have access.