CD123 binding proteins and related compositions and methods
The present disclosure relates to protein molecules that specifically bind to CD123, which may have at least one humanized or human CD123-binding domain. Such molecules are useful for the treatment of cancer. The protein molecule binding to CD123 may have a second binding domain that binds to another target. In one embodiment, multi-specific polypeptide molecules bind both CD123-expressing cells and the T-cell receptor complex on T-cells to induce target-dependent T-cell cytotoxicity, activation, and proliferation. The disclosure also provides pharmaceutical compositions comprising the CD123-binding polypeptide molecules, nucleic acid molecules encoding these polypeptides and methods of making these molecules.
1. A recombinant polypeptide comprising a CD123-binding domain and a CD3-binding domain,
wherein the CD123-binding domain comprises (i) an immunoglobulin light chain variable region comprising LCDR1, LCDR2, and LCDR3, and (ii) an immunoglobulin heavy chain variable region comprising HCDR1, HCDR2, and HCDR3, wherein the LCDR1 comprises the amino acid sequence set forth in SEQ ID NO:6; the LCDR2 comprises the amino acid sequence set forth in SEQ ID NO:8; the LCDR3 comprises the amino acid sequence set forth in SEQ ID NO:10, the HCDR1 comprises the amino acid sequence set forth in SEQ ID NO:12; the HCDR2 comprises the amino acid sequence set forth in SEQ ID NO:14; and the HCDR3 comprises the amino acid sequence set forth in SEQ ID NO: 16;
wherein the CD3-binding domain comprises: (i) an immunoglobulin light chain variable region comprising LCDR1, LCDR2, and LCDR3, and (ii) an immunoglobulin heavy chain variable region comprising HCDR1, HCDR2, and HCDR3, wherein
(a) the LCDR1, LCDR2 and LCDR3 of the CD3-binding domain comprise the amino acid sequences set forth in SEQ ID NO:162, SEQ ID NO:163, and SEQ ID NO:164, respectively, and the HCDR1, HCDR2, and HCDR3 of the CD3-binding domain comprise the amino acid sequences set forth in SEQ ID NO: 165, SEQ ID NO:166, and SEQ ID NO:167, respectively;
(b) the LCDR1, LCDR2 and LCDR3 of the CD3-binding domain comprise the amino acid sequences set forth in SEQ ID NO:168, SEQ ID NO:169, and SEQ ID NO:170, respectively, and the HCDR1, HCDR2, and HCDR3 of the CD3-binding domain comprise the amino acid sequences set forth in SEQ ID NO: 171, SEQ ID NO:172, and SEQ ID NO:173, respectively;
(c) the LCDR1, LCDR2 and LCDR3 of the CD3-binding domain comprise the amino acid sequences set forth in SEQ ID NO: 307, SEQ ID NO: 308 and SEQ ID NO:309, respectively, and the HCDR1, HCDR2, and HCDR3 of the CD3-binding domain comprise the amino acid sequences set forth in SEQ ID NO: 174, SEQ ID NO: 175 and SEQ ID NO:176, respectively;
(d) the LCDR1, LCDR2 and LCDR3 of the CD3-binding domain comprise the amino acid sequences set forth in SEQ ID NO: 310, SEQ ID NO: 177 and SEQ ID NO: 178, respectively, and the HCDR1, HCDR2, and HCDR3 of the CD3-binding domain comprise the amino acid sequences set forth in SEQ ID NO: 179, SEQ ID NO: 180 and SEQ ID NO: 181, respectively,
(e) the LCDR1, LCDR2 and LCDR3 of the CD3-binding domain comprise the amino acid sequences set forth in SEQ ID NO: 182, SEQ ID NO: 183 and SEQ ID NO: 184, respectively, and the HCDR1, HCDR2, and HCDR3 of the CD3-binding domain comprise the amino acid sequences set forth in SEQ ID NO: 185, SEQ ID NO: 186 and SEQ ID NO: 187, respectively; or
(f) the LCDR1, LCDR2 and LCDR3 of the CD3-binding domain comprise the amino acid sequences set forth in SEQ ID NO: 188, SEQ ID NO: 189 and SEQ ID NO: 190, respectively, and the HCDR1, HCDR2, and HCDR3 of the CD3-binding domain comprise the amino acid sequences set forth in SEQ ID NO: 191, SEQ ID NO: 192 and SEQ ID NO: 193, respectively.
2. The polypeptide of claim 1 , wherein the CD3-binding domain comprises an immunoglobulin light chain variable region and an immunoglobulin heavy chain variable region;
wherein the immunoglobulin light chain variable region of the CD3-binding domain comprises the amino acid sequence of SEQ ID NO:160; and
wherein the immunoglobulin heavy chain variable region of the CD3-binding domain comprises the amino acid sequence of SEQ ID NO:161.
3. The polypeptide of claim 1 , wherein the CD123-binding domain comprises:
(i) an immunoglobulin light chain variable region comprising the amino acid sequence of SEQ ID NO:2; and
(ii) an immunoglobulin heavy chain variable region comprising the amino acid sequence of SEQ ID NO:4.
4. The polypeptide of claim 1 , wherein the CD123-binding domain is a single chain variable fragment (scFv), and the CD3-binding domain is an scFv.
5. The polypeptide of claim 1 , comprising, in order from amino terminus to carboxyl terminus, (i) the CD123-binding domain, (ii) a hinge region, (iii) an immunoglobulin constant region, (iv) a carboxyl-terminus linker, and (v) the CD3-binding domain.
6. The polypeptide of claim 5 , wherein the carboxyl-terminus linker comprises an amino acid sequence comprising (Gly4Ser) n , wherein n=1-7 (SEQ ID NO:314).
7. The polypeptide of claim 6 , wherein n=3-5.
8. The polypeptide of claim 5 , wherein the carboxyl-terminus linker comprises SEQ ID NO:288.
9. The polypeptide of claim 5 , wherein the immunoglobulin constant region comprises immunoglobulin CH2 and CH3 domains of IgG1, IgG2, IgG3, IgG4, IgA1, IgA2 or IgD.
10. The polypeptide of claim 5 , wherein the immunoglobulin constant region comprises a human IgG1 CH2 domain comprising the substitutions L234A, L235A, G237A, and K322A, according to the EU numbering system.
11. A dimer comprising two identical polypeptides of claim 1 .
12. A pharmaceutical composition comprising the polypeptide of claim 1 and a pharmaceutically acceptable carrier, diluent, or excipient.
13. An isolated nucleic acid molecule encoding the recombinant polypeptide of claim 1 .
14. An expression vector comprising a nucleic acid segment encoding the polypeptide of claim 1 , wherein the nucleic acid segment is operatively linked to regulatory sequences suitable for expression of the nucleic acid segment in a host cell.
15. A recombinant host cell comprising the expression vector of claim 14 .