I summarised a scientific article released in August that discusses how VX809 helps F508del, how the folding can be improved further and other mutations that were helped by VX809 in this study:
http://sixtyfiverosesblog.wordpress.com/2013/10/18/how-does-vx809-help-f508del-part-2/
http://sixtyfiverosesblog.wordpress.com/2013/10/18/how-does-vx809-help-f508del-part-2/