Disclosed is a compound for formula 37 as depicted which is also known as 8-(1,3-dihydro-isoindol-2-ylmethyl)-2,9-dihydro-1,2, 7 ,9-tetraaza-phenalen-3-one. Also disclosed is a pharmaceutical composition comprising a compound of formula 37 and the use of a compound of formula 37 for the manufacture of a medicament for use is chemosensitizing or radiosensitizing cancer cells or for treating a cancer characterized by having a defect in the homologous recombination (HR) pathway of double stranded DNA repair.
