ABSTRACT - 598352 Disclosed herein is a poly(ADP-ribose)polymerase compound of formula (Ik), wherein the substituents R101, R102, R103, R104 & R105 are as defined within the specification. An example of a compound of formula (Ik) includes 4-(3-(1,4-diazepan-1-ylcarbonyl)-4-fluorobenzyl)-5,6,7,8-tetrahydrophthalazin-1(2H)-one. Further disclosed is a pharmaceutical composition comprising a compound of formula (Ik), and the use of a compound of formula (Ik) for treating cancer and reducing tumour volume.