Chimeric clotting factors
The invention provides chimeric clotting factors comprising an activatable clotting factor and an enhancer moiety. The activatable clotting factor allows the chimeric clotting factor to be activated at the site of coagulation. The enhancer moiety can additionally improve procoagulation activities of the chimeric clotting factors. The chimeric clotting factors can further be improved by fusion to a half-life extender, which improves a pharmacokinetics property of the chimeric clotting factor. The invention also includes methods of making and methods of using these chimeric clotting factors.
1. A chimeric protein comprising two polypeptides,
wherein (A) the first polypeptide comprises (i) an activatable Factor VII (Ac) and (ii) a first Fc domain (Het1), wherein the activatable Factor VII comprises a Factor VII (FVII) zymogen comprising a heavy chain (HC), a light chain (LC), and a protease-cleavage site that is not naturally occurring in the FVII zymogen inserted between the HC and the LC;
wherein (B) the second polypeptide comprises (i) a soluble Tissue Factor (Em) and (ii) a second Fc domain (Het2); and
wherein the chimeric protein has a higher thrombin activity compared to a reference FVII protein comprising an activated FVII (FVIIa) alone or an FVIIaFc fusion protein, as measured by a thrombin generation assay.
2. The chimeric protein according to claim 1 , wherein the first polypeptide comprises a structure represented by formula Ac-L1-Het1, and wherein Ac comprises the activatable FVII, L1 comprises a first linker, and Het1 comprises the first Fc domain; wherein the second polypeptide comprises a structure represented by formula Em-L2-Het2, wherein Em comprises the soluble Tissue Factor, L2 comprises a second linker, and Het2 comprises the second Fc domain.
3. The chimeric protein according to claim 1 , further a self-immolative moiety inserted between the protease-cleavage site and the HC.
4. The chimeric protein according to claim 1 , wherein the protease-cleavage site is cleaved by a protease selected from the group consisting of thrombin (factor IIa), factor XIIa, kallikrein, factor VIIa, factor IXa, and factor Xa.
5. The chimeric protein according to claim 3 , wherein the self-immolative moiety comprises p-amino benzyl carbamate (PABC), a p-amino benzyl ether (PABE), or a p-amino benzyl carbonate.
6. The chimeric protein according to claim 2 , wherein the L2 is identical to the L1.
7. The chimeric protein according to claim 2 , wherein the L1 and/or L2 comprises a gly/ser peptide.
8. The chimeric protein according to claim 1 , wherein the protease-cleavage site is a thrombin cleavage site.
9. The chimeric protein according to claim 1 , wherein an intracellular processing site is inserted between the LC of the FVII zymogen and the protease-cleavage site.
10. A pharmaceutical composition comprising the chimeric protein of claim 1 and a pharmaceutically acceptable carrier.
11. The chimeric protein according to claim 1 , wherein the Het1 and the Het2 are the same.
12. The chimeric protein according to claim 1 , wherein the Het1 and the Het2 are different.
13. The chimeric protein according to claim 2 , wherein the L2 is different from the L1.
14. The chimeric protein according to claim 3 , wherein the self-immolative moiety is PABC.