Multi-specific binding proteins that bind bcma, nkg2d and cd16, and methods of use

A protein comprising:

• (a) a first antigen-binding site comprising a single-chain variable fragment (scFv) that binds NKG2D and comprises the amino acid sequence of SEQ ID NO:190, the amino acid sequence of SEQ ID NO:96, the amino acid sequence of SEQ ID NO:191, the amino acid sequence of SEQ ID NO:99, the amino acid sequence of SEQ ID NO:100, and the amino acid sequences of SEQ ID NO:101;
• (b) a second antigen-binding site that binds B-cell maturation antigen (BCMA) and comprises the amino acid sequence of SEQ ID NO:149, the amino acid sequence of SEQ ID NO:150, the amino acid sequence of SEQ ID NO:151, the amino acid sequence of SEQ ID NO:153, the amino acid sequence of SEQ ID NO:154, and the amino acid sequences of SEQ ID NO:155;
• (c) an additional antigen-binding site that binds BCMA and comprises the amino acid sequence of SEQ ID NO:149, the amino acid sequence of SEQ ID NO:150, the amino acid sequence of SEQ ID NO:151, the amino acid sequence of SEQ ID NO:153, the amino acid sequence of SEQ ID NO:154, and the amino acid sequences of SEQ ID NO:155;
• and
• (d) an antibody Fc domain or a portion thereof sufficient to bind CD16.

A pharmaceutical composition comprising a protein and a pharmaceutically acceptable carrier, wherein the protein comprises:

• (a) a first antigen-binding site comprising a single-chain variable fragment (scFv) that binds NKG2D and comprises the amino acid sequence of SEQ ID NO:190, the amino acid sequence of SEQ ID NO:96, the amino acid sequence of SEQ ID NO:191, the amino acid sequence of SEQ ID NO:99, the amino acid sequence of SEQ ID NO:100, and the amino acid sequences of SEQ ID NO:101;
• (b) a second antigen-binding site that binds B-cell maturation antigen (BCMA) and comprises the amino acid sequence of SEQ ID NO:149, the amino acid sequence of SEQ ID NO:150, the amino acid sequence of SEQ ID NO:151, the amino acid sequence of SEQ ID NO:153, the amino acid sequence of SEQ ID NO:154, and the amino acid sequences of SEQ ID NO:155;
• (c) an additional antigen-binding site that binds BCMA and comprises the amino acid sequence of SEQ ID NO:149, the amino acid sequence of SEQ ID NO:150, the amino acid sequence of SEQ ID NO:151, the amino acid sequence of SEQ ID NO:153, the amino acid sequence of SEQ ID NO:154, and the amino acid sequences of SEQ ID NO:155;
• and
• (d) an antibody Fc domain or a portion thereof sufficient to bind CD16.

A nucleic acid encoding:

• (a) a polypeptide comprising the amino acid sequence of SEQ ID NO:162;
• (b) a polypeptide comprising the amino acid sequence of SEQ ID NO:163;
• or
• (c) a polypeptide comprising the amino acid sequence of SEQ ID NO:165.

A method of treating BCMA-expressing cancer comprising administering a therapeutically effective amount of a protein to a patient in need thereof, wherein the protein comprises:

• (a) a first antigen-binding site comprising a single-chain variable fragment (scFv) that binds NKG2D and comprises the amino acid sequence of SEQ ID NO:190, the amino acid sequence of SEQ ID NO:96, the amino acid sequence of SEQ ID NO:191, the amino acid sequence of SEQ ID NO:99, the amino acid sequence of SEQ ID NO:100, and the amino acid sequences of SEQ ID NO:101;
• (b) a second antigen-binding site that binds B-cell maturation antigen (BCMA) and comprises the amino acid sequence of SEQ ID NO:149, the amino acid sequence of SEQ ID NO:150, the amino acid sequence of SEQ ID NO:151, the amino acid sequence of SEQ ID NO:153, the amino acid sequence of SEQ ID NO:154, and the amino acid sequences of SEQ ID NO:155;
• (c) an additional antigen-binding site that binds BCMA and comprises the amino acid sequence of SEQ ID NO:149, the amino acid sequence of SEQ ID NO:150, the amino acid sequence of SEQ ID NO:151, the amino acid sequence of SEQ ID NO:153, the amino acid sequence of SEQ ID NO:154, and the amino acid sequences of SEQ ID NO:155;
• and
• (d) an antibody Fc domain or a portion thereof sufficient to bind CD16.