The present invention is concerned with the finding that some the macrocyclic quinazoline derivative 4,6-ethanediylidenepyrimido[4,5-b][6,1,12]benzoxadiazacyclo-pentadecine, 17-bromo-8,9,10,11,12,13,14,19-octahydro-20-methoxy-13-methyl-, described as compound 22 in PCT publication W02004/105765, is useful in the manufacture of a medicament for the treatment or prevention of a primary brain cancer or brain metastasis. It accordingly provides methods for treating, preventing, delaying or mitigating brain cancer, or for preventing or slowing proliferation of cells of brain origin.