Compounds, linker units comprising the same, and uses thereof in treating diseases

Abstract

Provided herein is a compound having the structure of formula (I), wherein X1 is an acidic β-homo-amino acid or an acidic α-methyl-amino acid; X2 is valine (V) or leucine (L); X3 is citrulline, alanine (A) or lysine (K); A1, A2 and A3 are independently nil or a polyethylene glycol (PEG) moiety comprising 1 to 24 repeats of ethylene glycol (EG) unit; and A3 is nil when X3 is not lysine. Also provided herein are linker units including the present compound of formula (I) for linking effector elements, and antibody-drug conjugates (ADCs) including the present linker units.