Patent ID: 6878699

Claim:
A method of inhibiting the proliferation of a hyperproliferative mammalian cell having a multiple drug resistant phenotype, said method comprising contacting a hyperproliferative mammalian cell having a multiple drug resistant phenotype with an amount of a taccalonolide compound effective to disrupt the dynamic state of microtubule polymerization and depolymerization to arrest cell mitosis, thereby inhibiting the proliferation of the cell, wherein said taccalonolide has the structure: wherein: R 1 =hydroxy, lower alkoxy or acyloxy, R 2 =OH, or R 2 and R 3 cooperate to form an epoxide at C-2/C-3, R 3 =OH, or R 3 cooperates with R 2 to form an epoxide at C-2/C-3, R 6 =OH, or a carbonyl oxygen if R 6′ is not present, R 6′ , when present, is H, R 7 =hydroxy, lower alkoxy or acyloxy, R 8 =H, R 11 =H, hydroxy, lower alkoxy or acyloxy, R 12 =hydroxy, lower alkoxy or acyloxy, R 15 =hydroxy, tower alkoxy or acyloxy, R 16 =H, R 18 =H or lower alkyl, R 19 =lower alkyl, R 21 =lower alkyl, R 26 =hydroxy, lower alkoxy or acyloxy, R 26′ =lower alkyl, R 27 =carbonyl oxygen and R 27′ is not present, R 28 =H or lower alkyl; and X=O, and wherein the dashed lines between C2/C3, C6/C7, C11/C2 and C22/23 represent optional double bonds at each position.