Peptide conjugates of cytotoxins as therapeutics

A compound of Formula (I):

• R8-Q-R7 (I)
• or a pharmaceutically acceptable salt thereof, wherein:
• R7 is a peptide;
• R8 is:
• Q is:
• R1 and R3 together with the carbon atoms to which they are attached form a C3-14 cycloalkyl group or 4-14 membered heterocycloalkyl group, each optionally substituted with 1, 2, or 3 substituents independently selected from C1-4 alkyl, halo, CN, NO2, ORa1, SRa1, C(O)Rb1, C(O)NRc1Rd1, C(O)ORa1, OC(O)Rb1, OC(O)NRc1Rd1, NRc1Rd1, NRc1C(O)Rb1, NRc1C(O)ORa1, and NRc1C(O)NRc1Rd1,
• R2 and R4 are each independently selected from H, C1-4 alkyl, C1-4 alkenyl, C6-10 aryl, C3-10 cycloalkyl, 5-10 membered heteroaryl, 4-10 membered heterocycloalkyl, halo, CN, NO2, ORa1, SRa1, C(O)Rb1, C(O)NRc1NRd1, C(O)ORa1, OC(O)Rb1, OC(O)NRc1Rd1, NRc1Rd1, NRc1C(O)Rb1, NRc1C(O)ORa1, and NRc1C(O)NRc1Rd1, wherein said C1-4 alkyl, C1-4 alkenyl, C6-10 aryl, C3-10 cycloalkyl, 5-10 membered heteroaryl, and 4-10 membered heterocycloalkyl, are each optionally substituted with 1, 2, or 3 substituents independently selected from halo, CN, NO2, ORa1, SRa1, C(O)Rb1, C(O)NRc1Rd1, C(O)ORa1, OC(O)Rb1, OC(O)NRc1Rd1, NRc1Rd1, NRc1C(O)Rb1, NRc1C(O)ORa1, and NRc1C(O)NRc1Rd1;
• and
• Ra1, Rb1, Rc1, and Rd1 are each independently selected from H, C1-6 alkyl, C2-6 alkenyl, C2-6 alkynyl, C1-6 haloalkyl, OH, CN, NO2, and CO2CH3;
• wherein said C1-6 alkyl and C2-6 alkenyl are each optionally substituted with OH, CN, NO2, or CO2CH3.