Abstract: Camptothecin analogues of Formula (I) and conjugates comprising the camptothecin analogues are described. The camptothecin analogues and conjugates may be used as therapeutic agents, particularly in the treatment of cancer, an autoimmune disease or a viral infection.

Abstract: Compounds having cytotoxic and/or anti-mitotic activity are disclosed. Methods associated with preparation and use of such compounds, as well as pharmaceutical compositions comprising such compounds, are also disclosed. Also disclosed are compositions having the structure: (T)-(L)-(D), wherein (T) is a targeting moiety, (L) is an optional linker, and (D) is a compound having cytotoxic and/or anti-mitotic activity.