a pharmaceutical combination comprising a compound of formula , or pharmaceutically acceptable salts thereof ; and one or more at least one compound targeting , decreasing or inhibiting the intrinsic atpase activity of hsp90 and / or degrading , targeting , decreasing or inhibiting the hsp90 client proteins via the ubiquitin proteosome pathway ; the uses of such combination in the treatment or prevention of proliferative diseases ; and methods of treating a subject suffering from a proliferative disease ; and methods of treating a subject suffering from a proliferative disease comprising administering a therapeutically effective amount of such combination .