A compound of Formula (Va), (Vb), (Vc), (Vd), (Ve), or (Vf): or a tautomer thereof, or a pharmaceutically acceptable salt of the compound or the tautomer, for use as a medicament; wherein R 3 is each of R 4 and R 4' independently is -Q 3 -T 3, in which each Q 3 independently is a bond or C 1 -C 6 alkylene, C 2 -C 6 alkenylene, or C 2 -C 6 alkynylene linker optionally substituted with one or more of halo, cyano, hydroxyl, amino, mono- or di- alkylamino, or C 1 -C 6 alkoxyl, and each T 3 independently is H, halo, cyano, OR 7, OR 8, C R 8, NR 7 R 8, C NR 7 R 8, NR 7 C R 8, C 6 -C 10 aryl, 5- to 10-membered heteroaryl, C 3 -C 12 cycloalkyl, or 4- to 12-membered heterocycloalkyl containing 1-4 heteroatoms selected from N, O, and S, and wherein the C 6 -C 10 aryl, 5- to 10-membered heteroaryl, C 3 -C 12 cycloalkyl or 4- to 12-membered heterocycloalkyl is optionally substituted with one or more of halo, hydroxyl, cyano, C 1 -C 6 haloalkyl, -SO 2 R 5, C 1 -C 6 alkoxyl or C 1 -C 6 alkyl optionally substituted with one or more of NR 5 R 6; each of R 5, R 6, and R 7, independently, is H or C 1 -C 6 alkyl optionally substituted with one or more of halo, cyano, hydroxyl, amino, mono- or di- alkylamino, or C 1 -C 6 alkoxyl; and R 8 is -Q 4 -T 4, in which Q 4 is a bond or C 1 -C 6 alkylene, C 2 -C 6 alkenylene, or C 2 -C 6 alkynylene linker optionally substituted with one or more of halo, cyano, hydroxyl, or C 1 -C 6 alkoxyl, and T 4 is H, halo, or R S3, in which R S3 is C 3 -C 12 cycloalkyl, C 6 -C 10 aryl, 4- to 12-membered heterocycloalkyl containing 1-4 heteroatoms selected from N, O and S, or a 5- to 10-membered heteroaryl, and R S3 is optionally substituted with one or more -Q 5 -T 5, wherein each Q 5 independently is a bond or C 1 -C 3 alkylene, C 2 -C 3 alkenylene, or C 2 -C 3 alkynylene linker each optionally substituted with one or more of halo, cyano, hydroxyl, or C 1 -C 6 alkoxy, and each T 5 independently is selected from the group consisting of H, halo, cyano, C 1 -C 6 alkyl, C 3 -C 12 cycloalkyl, C 6 -C 10 aryl, 4- to 7-membered heterocycloalkyl containing 1-4 heteroatoms selected from N, O, and S, 5- to 6-membered heteroaryl, OR c, C R c, NR c R d, C NR c R d, S 2 R c, and NR c C R d, each of R c and R d independently being H or C 1 -C 6 alkyl optionally substituted with one or more halo; or -Q 5 -T 5 is oxo. R 3 is each of R 4 and R 4' independently is -Q 3 -T 3, in which each Q 3 independently is a bond or C 1 -C 6 alkylene, C 2 -C 6 alkenylene, or C 2 -C 6 alkynylene linker optionally substituted with one or more of halo, cyano, hydroxyl, amino, mono- or di- alkylamino, or C 1 -C 6 alkoxyl, and each T 3 independently is H, halo, cyano, OR 7, OR 8, C R 8, NR 7 R 8, C NR 7 R 8, NR 7 C R 8, C 6 -C 10 aryl, 5- to 10-membered heteroaryl, C 3 -C 12 cycloalkyl, or 4- to 12-membered heterocycloalkyl containing 1-4 heteroatoms selected from N, O, and S, and wherein the C 6 -C 10 aryl, 5- to 10-membered heteroaryl, C 3 -C 12 cycloalkyl or 4- to 12-membered heterocycloalkyl is optionally substituted with one or more of halo, hydroxyl, cyano, C 1 -C 6 haloalkyl, -SO 2 R 5, C 1 -C 6 alkoxyl or C 1 -C 6 alkyl optionally substituted with one or more of NR 5 R 6; each of R 5, R 6, and R 7, independently, is H or C 1 -C 6 alkyl optionally substituted with one or more of halo, cyano, hydroxyl, amino, mono- or di- alkylamino, or C 1 -C 6 alkoxyl; and R 8 is -Q 4 -T 4, in which Q 4 is a bond or C 1 -C 6 alkylene, C 2 -C 6 alkenylene, or C 2 -C 6 alkynylene linker optionally substituted with one or more of halo, cyano, hydroxyl, or C 1 -C 6 alkoxyl, and T 4 is H, halo, or R S3, in which R S3 is C 3 -C 12 cycloalkyl, C 6 -C 10 aryl, 4- to 12-membered heterocycloalkyl containing 1-4 heteroatoms selected from N, O and S, or a 5- to 10-membered heteroaryl, and R S3 is optionally substituted with one or more -Q 5 -T 5, wherein each Q 5 independently is a bond or C 1 -C 3 alkylene, C 2 -C 3 alkenylene, or C 2 -C 3 alkynylene linker each optionally substituted with one or more of halo, cyano, hydroxyl, or C 1 -C 6 alkoxy, and each T 5 independently is selected from the group consisting of H, halo, cyano, C 1 -C 6 alkyl, C 3 -C 12 cycloalkyl, C 6 -C 10 aryl, 4- to 7-membered heterocycloalkyl containing 1-4 heteroatoms selected from N, O, and S, 5- to 6-membered heteroaryl, OR c, C R c, NR c R d, C NR c R d, S 2 R c, and NR c C R d, each of R c and R d independently being H or C 1 -C 6 alkyl optionally substituted with one or more halo; or -Q 5 -T 5 is oxo.