Disclosed is a use of a therapeutic amount of apaziquone for manufacturing a medicament for administration within about 6 hours following transurethral resection of bladder tumour (TUR-BT) for treating a bladder cancer. Apaziquone is also known as E09 or NSC-382459 and is 5-(aziridin-1-yl)-3-(hydroxymethyl)-2-[(1E)-3-hydroxyprop-1-enyl]-1-methyl-1H-indole-4,7-dione with the structural formula as depicted.