Abstract: The present invention discloses a method for targeting maytansinoids to a selected cell population, the method comprising contacting a cell population or tissue suspected of containing the selected cell population with a cell-binding agent maytansinoid conjugate, wherein one or more maytansinoids is covalently linked to the cell-binding agent via a non-cleavable linker and the cell-binding agent binds to cells of the selected cell population.

Abstract: The present invention discloses a method for targeting maytansinoids to a selected cell population, the method comprising contacting a cell population or tissue suspected of containing the selected cell population with a cell-binding agent maytansinoid conjugate, wherein one or more maytansinoids is covalently linked to the cell-binding agent via a non-cleavable linker and the cell-binding agent binds to cells of the selected cell population.

Abstract: The present invention discloses a method for targeting maytansinoids to a selected cell population, the method comprising contacting a cell population or tissue suspected of containing the selected cell population with a cell-binding agent maytansinoid conjugate, wherein one or more maytansinoids is covalently linked to the cell-binding agent via a non-cleavable linker and the cell-binding agent binds to cells of the selected cell population.

Abstract: New thiol and disulfide-containing maytansinoids bearing a mono or di-alkyl substitution on the ?-carbon atom bearing the sulfur atom are disclosed. Also disclosed are methods for the synthesis of these new maytansinoids and methods for the linkage of these new maytansinoids to cell-binding agents. The maytansinoid-cell-binding agent conjugates are useful as therapeutic agents, which are delivered specifically to target cells and are cytotoxic. These conjugates display vastly improved therapeutic efficacy in animal tumor models compared to the previously described agents.

Abstract: New thiol and disulfide-containing maytansinoids bearing a mono or di-alkyl substitution on the ?-carbon atom bearing the sulfur atom are disclosed. Also disclosed are methods for the synthesis of these new maytansinoids and methods for the linkage of these new maytansinoids to cell-binding agents. The maytansinoid-cell-binding agent conjugates are useful as therapeutic agents, which are delivered specifically to target cells and are cytotoxic. These conjugates display vastly improved therapeutic efficacy in animal tumor models compared to the previously described agents.

Abstract: New thiol and disulfide-containing maytansinoids bearing a mono or di-alkyl substitution on the ?-carbon atom bearing the sulfur atom are disclosed. Also disclosed are methods for the synthesis of these new maytansinoids and methods for the linkage of these new maytansinoids to cell-binding agents. The maytansinoid-cell-binding agent conjugates are useful as therapeutic agents, which are delivered specifically to target cells and are cytotoxic. These conjugates display vastly improved therapeutic efficacy in animal tumor models compared to the previously described agents.

Abstract: The present invention describes the preparation of maytansinol by methods that minimize processing steps, and reduce solvent volumes, making the process more efficient, and scaleable. This process comprises a step of converting bridged acetals of maytansinol to maytansinol. The simplified processing also aids in lowering the potential for human exposure to chemicals. Also provided is an isolated C3 to C9 bridged acetal of maytansinol.

Abstract: Improved processes for the preparation and purification of maytansinoid esters, especially thiol and disulfide-containing maytansinoids are described. In one aspect the process comprises a process of making a maytansinoid ester comprising forming an anion of maytansinol or a maytansinoid bearing a free C-3 hydroxyl moiety and reacting the anion with an activated carboxyl compound to thereby produce the maytansinoid ester.

Abstract: A process of the large-scale fermentation of a highly productive ansamitocin-producing strains. A method for isolating crude ansamitocins. A method for purifying ansamitocins.