A lipophilic preparation of 7-ethyl-10-hydroxycamptothecin (SN-38) with potential antineoplastic activity. Tenifatecan is an oil-in-water emulsion of tocopherol covalently linked, via a succinate linker, to SN-38, an active metabolite of the camptothecin derivative irinotecan. After the succinate linker is hydrolyzed in vivo, the active moiety SN-38 is released and selectively stabilizes topoisomerase I-DNA covalent complexes, thereby inhibiting religation of topoisomerase I-mediated single-stranded DNA breaks and inducing lethal double-stranded DNA breaks; DNA replication is inhibited and apoptosis is triggered. This agent may provide greater delivery and exposure of SN-38 to the tumor than can be achieved with irinotecan.