Compositions and methods for conjugating activatable antibodies

摘要

The invention relates generally to compositions and methods for conjugating antibodies and activatable antibodies, and methods of partially reducing antibodies and/or activatable antibodies prior to conjugation, e.g., thiol-based conjugation, with an agent, e.g., a therapeutic and/or diagnostic agent.

主权项

1. A method of partially reducing and conjugating an agent to an activatable antibody resulting in selectivity in the placement of the agent, the method comprising
partially reducing at least one disulfide bond in the activatable antibody with a reducing agent without disturbing any intrachain disulfide bonds in the activatable antibody, wherein the reducing agent is tris(2-carboxyethyl)phosphine (TCEP), and conjugating the agent to at least one thiol, wherein the activatable antibody comprises an antibody or an antigen binding fragment thereof (AB) that specifically binds to epidermal growth factor receptor (EGFR), wherein the AB comprises a heavy chain comprising an amino acid sequence selected from the group consisting of SEQ ID NOS: 2, 239, and 241, and a light chain comprising an amino acid sequence of SEQ ID NO: 16, a masking moiety (MM) comprising an amino acid sequence selected from the group consisting of SEQ ID NOS: 29 to 63 that inhibits the binding of the AB of the activatable antibody in an uncleaved state to the target, and a cleavable moiety (CM) comprising an amino acid sequence selected from the group consisting of SEQ ID NOS: 183-202 and 298-318 coupled to the AB, wherein the CM is a polypeptide that functions as a substrate for a protease.