Fibroblast activation protein (FAP)—targeted antifibrotic therapy

A compound of formula (A) or (B):

• or a pharmaceutically acceptable salt thereof, wherein:
• Ia is
• wherein X is:
• wherein * denotes the point of attachment of X to Ia or L or Fa;
• and ** denotes the point of attachment of X to:
• L is
• x is an integer from 0 to 10;
• and
• y is an integer from 3 to 100;
• or
• L is:
• wherein:
• R18a, R18b, R19a, and R19b are independently H or C1-6alkyl;
• and
• R31 is H or C1-6alkyl;
• Fa is a fibroblast activation protein alpha (FAPα) targeting moiety having a structure represented by the following formula (X):
• wherein:
• wherein *** denotes the point of attachment to J;
• R1 is selected from the group consisting of —H, —CN, —B(OH)2, —C(O)alkyl, —C(O)aryl, —C═CC(O)aryl, —C═C—S(O)2aryl, —CO2H, —SO3H, —SO2NH2, —PO3H2, and 5-tetrazolyl,
• R2, R3a, R3b and R4 are each independently selected from the group consisting of —H, —OH, halogen, —C1-6alkyl, —O—C1-6alkyl, and —S—C1-6alkyl,
• R5 is —CH3,
• R6, R7, and R8 are each independently selected from the group consisting of —H, —OH, oxo, halogen, CF3, —C1-6alkyl, —O—C1-6alkyl, —S—C1-6alkyl, —NR9R10, —OR11, —Het2, and —Ar2;
• each of —C1-6alkyl being optionally substituted with from 1 to 3 substituents selected from —OH and halogen;
• R9, R10, and R11 are each independently selected from the group consisting of —H, —OH, oxo, halogen, CF3, —C1-6alkyl, —O—C1-6alkyl, —S—C1-6alkyl, and —Ar3,
• Ar2 and Ar3 are each independently a 5- or 6-membered aromatic monocycle optionally comprising 1 or 2 heteroatoms selected from O, N, and S;
• each of Ar2 and Ar3 being optionally and independently substituted with from 1 to 3 substituents selected from —NR12R13, —C1-6alkyl, —O—C1-6alkyl, and —S—C1-6alkyl,
• R12 and R13 are each independently selected from the group consisting of —H, —OH, CF3, —C1-6alkyl, —O—C1-6alkyl, and —S—C1-6alkyl,
• Het2 is a 5- or 6-membered non-aromatic monocycle optionally comprising 1 or 2 heteroatoms selected from O, N and S;
• Het2 being optionally substituted with from 1 to 3 substituents selected from —NR14R15, —C1-6alkyl, —O—C1-6alkyl, and —S—C1-6alkyl,
• R14 and R15 are each independently selected from the group consisting of —H, —OH, halogen, CF3, —C1-6alkyl, —O—C1-6alkyl, and —S—C1-6alkyl;
• J is selected from the group consisting of a bond, —C1-3alkyl, —C1-3alkyl-NH—, C═O, and —O;
• and the compound is not