I think it may be that Azixa has that strange property of collecting in the brain at 14 times the level in the body, while the other doesn't. Pedrorojo on the mygn message board suggested that Azixa may not have a powerful effect in the body. Maybe EPC2407 does?
Needless to say, this is just conjecture. Hope it helps. If you find out anything more substantive, let us know!
Incidentally, this property plus its dual mode of action and low side effect profile make Azixa very promising for many types of brain cancer. More promising than the epc2407 I would guess since more is known about it. Collecting in the brain like that is very unusual, maybe unique for a cancer drug.