Compounds specific to granzyme b and uses thereof

A compound of formula (I):

• or a stereoisomer, tautomer, or a salt thereof,
• wherein:
• M is a radioactive moiety;
• A is a chelating moiety chelating the radioactive moiety;
• X is selected from the group consisting of —CH2C(NH)—, —CH2C(O)—, —CH2C(S)—, —NHC(NH)—, —NHC(O)—, —NHC(S)—, —OC(NH)—, —OC(O)—, and —OC(S)—, optionally wherein X is —CH2C(O)— or —NHC(S)—;
• Y is CH or N;
• Z is —CH2—, —CH2C(NH)—, —CH2C(O)—, —CH2C(S)—, —NHC(NH)—, —NHC(O)—, —NHC(S)—, —O(NH)—, —O—C(O)—, or —OC(S)—;
• optionally wherein Z is —CH2— or —CH2C(O)—;
• L is a peptide linker having 1-6 amino acid residues, inclusive;
• R1 is H or C1-6 alkyl, optionally wherein R1 is H or methyl;
• and
• R2 is C1-6 alkyl or C3-6 cycloalkyl.