A four arm-polyethylene glycol-7-ethyl-10- hydroxy camptothecin conjugate, such as,is disclosed. Methods of making the conjugates and methods of treating mammals using the same are also disclosed.本發明揭露一種4臂聚乙二醇-7-乙基-10-羥喜樹鹼共軛物,例如,。本發明也揭露製造共軛物的方法以及利用共軛物治療哺乳動物的方法。