Disclosed herein is a method of treating breast cancer that has metastasized to the brain in a mammal by administration of 4-quinazolinamines and pharmaceutical compositions containing the same. In particular, the method relates to methods of treating breast cancer brain metastases which overexpress erbB2 by administration of N-{3-chloro-4-[(3-fluorobenzyl)oxy]phenyl}-6-[5-({[2-(methanesulphonyl)ethyl]amino}methyl)-2-furyl]-4-quinazolinamine and salts and solvates thereof.