Tri-specific binding molecules that specifically bind to multiple cancer antigens

A multi-chain polypeptide-containing Tri-Specific Binding Molecule that immunospecifically binds to three different epitopes, comprising:

• (I) three different polypeptide chains covalently complexed together;
• (II) an Antigen-Binding Domain I that immunospecifically binds to an Epitope I present on a first antigen, an Antigen-Binding Domain II that immunospecifically binds to an Epitope II present on a second antigen, and an Antigen-Binding Domain III that immunospecifically binds to an Epitope III present on a third antigen;
• and
• (III) a Fc Domain;
• wherein:
• (A) one of Epitope I, Epitope II or Epitope III is an epitope of an Effector Cell Antigen, a second of Epitope I, Epitope II or Epitope III is an epitope of a first Cancer Antigen, and a third of Epitope I, Epitope II or Epitope III is an epitope of a second Cancer Antigen;
• (B) a first polypeptide chain comprises, in the N-terminus to C-terminus direction:
• (VLI Domain)-(Linker 1)-(VHII Domain)-(Linker 2)-(Heterodimer-Promoting Domain)-(Linker 3)-(CH2-CH3 Domain);
• or
• (Cysteine-Containing Domain)-(CH2-CH3 Domain)-(Linker 4)-(VLI Domain)-(Linker 1)-(VHII Domain)-(Linker 2)-(Heterodimer-Promoting Domain);
• (C) a second polypeptide chain comprises, in the N-terminus to C-terminus direction:
• (VLII Domain)-(Linker 1)-(VHI Domain)-(Linker 2)-(Heterodimer-Promoting Domain);
• (D) a third polypeptide chain comprises, in the N-terminus to C-terminus direction:
• (VLIII Domain)-(Flexible Linker)-(VHIII Domain)-(Cysteine-Containing Domain)-(CH2-CH3 Domain);
• or
• (CL Domain)-(VLIII Domain)-(Flexible Linker)-(VHIII Domain)-(CH1 Domain)-(Cysteine-Containing Domain)-(CH2-CH3 Domain);
• (E) the VLI Domain is a Light Chain Variable Domain of an immunoglobulin that binds to Epitope I, the VHI Domain is a Heavy Chain Variable Domain of an immunoglobulin that binds to Epitope I, the VLII Domain is a Light Chain Variable Domain of an immunoglobulin that binds to Epitope II, the VHII Domain is a Heavy Chain Variable Domain of an immunoglobulin that binds to Epitope II, the VLIII Domain is a Light Chain Variable Domain of an immunoglobulin that binds to Epitope III, and the VHIII Domain is a Heavy Chain Variable Domain of an immunoglobulin that binds to Epitope III;
• (F) the VLI Domain and the VHI Domain associate to form the Antigen-Binding Domain I, the VLII Domain and the VHII Domain associate to form the Antigen-Binding Domain II, the VLIII Domain and the VHIII Domain associate to form the Antigen-Binding Domain III, and the CH2-CH3 Domain of the first polypeptide chain and the CH2-CH3 Domain of the third polypeptide chain associate to form the Fc Domain;
• and
• (G) the Linker 1 comprises the sequence of SEQ ID NO:
• 33;
• the Linker 2 comprises the sequence of SEQ ID NO:
• 34 or 47;
• the Linker 3 comprises the sequence of SEQ ID NO:
• 46, 47, 48, 49, 50, 51, 152, or GCG or GGG;
• the Linker 4 comprises the sequence of SEQ ID NO:
• 50 or 152;
• the Heterodimer-Promoting Domain on the first polypeptide chain is an E-coil Domain and the Heterodimer-Promoting Domain on the second polypeptide chain is a K-coil Domain, or the Heterodimer-Promoting Domain on the first polypeptide chain is a K-coil Domain and the Heterodimer-Promoting Domain on the second polypeptide chain is an E-coil Domain, the E-coil Domain independently comprises the sequence of SEQ ID NO:
• 39 or 41, and the K-coil Domain independently comprises the sequence of SEQ ID NO:
• 40 or 42;
• the Cysteine-Containing Domain independently comprises the sequence of SEQ ID NO:
• 34, 36, 38, 48, 210 or 211;
• the CH1 Domain comprises the sequence of SEQ ID NO:
• 207 or 208;
• and
• the CL Domain comprises the sequence of SEQ ID NO:
• 210 or 211.