Patent ID: 8435528

Claim:
A method of treating a tumor comprising administering to a subject in need of treatment an effective amount of a maytansinoid-cell-binding agent conjugate or a pharmaceutically acceptable salt or solvate thereof, wherein the maytansinoid-cell-binding agent conjugate comprises at least one maytansinoid linked to the cell-binding agent, wherein the maytansinoid is represented by formula (II-L), (II-D) or (II-D, L): wherein: Y 1 represents (CR 7 R 8 ) l (CR 5 R 6 ) m (CR 3 R 4 ) n CR 1 R 2 S—, wherein: R 1 and R 2 are each independently linear alkyl or alkenyl having from 1 to 10 carbon atoms, branched or cyclic alkyl or alkenyl having from 3 to 10 carbon atoms, phenyl or substituted phenyl, and in addition R 2 can be H; R 3 , R 4 , R 5 , R 6 , R 7 and R 8 are each independently H, linear alkyl or alkenyl having from 1 to 10 carbon atoms, branched or cyclic alkyl or alkenyl having from 3 to 10 carbon atoms, phenyl or substituted phenyl; l, m and n are each independently an integer of from 1 to 5, and in addition n can be 0; and May represents a maytansinoid which bears the side chain at C-3, C-14 hydroxymethyl, C-15 hydroxy or C-20 desmethyl.