sentence: Hopefully , the demonstration of the safety of rAAV administration into the human brain ( Kaplitt et al ., 2007 ; Marks et al ., 2008 ; LeWitt et al ., 2011 ; Leone et al ., 2012 ; Bartus et al ., 2013 ; Tardieu et al ., 2014 ; Warren Olanow et al ., 2015 ) will pave the way for new trials enrolling less advanced patients .