Abstract: The present invention relates to water soluble, camptothecin derivatives of formula (I). ##STR1## wherein A represents a moiety of the formula (IIA), (IIB) or (IIC): ##STR2## X is selected from the group consisting of alkyl, aryl, (CH.sub.2).sub.m OR.sup.1, (CH.sub.2).sub.m SR.sup.1 and (CH.sub.2).sub.m NR.sup.1 R.sup.2 wherein m is an integer of 0 to 6, and R.sup.1 and R.sup.2 are hydrogen, lower alkyl, aryl or together with the nitrogen form a 5-7 membered ring; q is an integer of 0 to 2; n represents the integer 1 or 2; p is an integer of 1 to 6; Y and W are selected from the group consisting of alkyl, aryl, alkoxy, aryloxy and amino, Q is oxygen or sulfur; P is phosphorus; J represents the atoms necessary to complete a 5 or 6 membered aromatic ring; and the pharmaceutically acceptable salts thereof; their use as topoisomerase inhibitors, their preparation; and their use in the treatment of cancer.