Splicing modulator antibody-drug conjugates and methods of use

A compound of Formula (VI-A):

• or a pharmaceutically acceptable salt thereof, wherein:
• R1 and R9 are each independently chosen from absent, hydrogen, C1-C6 alkyl groups, C1-C6 alkylalkoxy groups, C1-C6 alkylamino groups, C1-C6 alkylcarboxylic acid groups, C1-C6 alkylhydroxy groups, C3-C8 cycloalkyl groups, benzyl groups, C3-C8 heterocyclyl groups, —O—C(=O)—(C1-C6 alkyl) groups, and —CD3;
• R3 is chosen from hydrogen, C1-C6 alkyl groups, C1-C6 alkylalkoxy groups, C1-C6 alkylamino groups, C1-C6 alkylcarboxylic acid groups, C1-C6 alkylhydroxy groups, C3-C8 cycloalkyl groups, benzyl groups, C3-C8 heterocyclyl groups, and —O—C(=O)—(C1-C6 alkyl) groups;
• R4, R5, and R8 are each independently chosen from hydrogen, hydroxyl, —O—(C1-C6 alkyl) groups, —O—C(=O)—(C1-C6 alkyl) groups, and C1-C6 alkyl groups;
• R6 and R7 are each independently chosen from hydrogen, —O—R17, —O—C(=O)—R17, —O—C(=O)—NR15R16, C1-C6 alkyl groups, and —NR15R16;
• R10 is chosen from hydrogen, C1-C6 alkyl groups, —C(=O)—(C1-C6 alkyl) groups, and —CD3;
• R15 and R16 are each independently chosen from hydrogen, R17, —C(=O)—R17, and —C(=O)—O—R17;
• R17 is chosen from hydrogen, C1-C6 alkyl groups, C3-C8 cycloalkyl groups, benzyl groups, and C3-C8 heterocyclyl groups;
• and
• a is 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10;
• wherein R1, R3, R4, R5, R6, R7, R8, R9, and R10 are each independently substituted with 0 to 3 groups independently chosen from halogens, hydroxyl, C1-C6alkyl groups, —O—(C1-C6 alkyl) groups, —NR15R16, C3-C8 cycloalkyl groups, C1-C6 alkylhydroxy groups, C1-C6 alkylalkoxy groups, benzyl groups, and C3-C8 heterocyclyl groups;
• wherein at least one of R6 and R7 is hydrogen;
• wherein R1 and R9 cannot both be absent;
• and
• L is a linker.