Coagulation factor VII (EC3.4.21.21, formerly known as proconvertin) is a protein involved in coagulation and, in humans, is encoded by geneF7. It is an enzyme of the serine protease class. Once bound to tissue factor released from damaged tissues, it is converted to factor VIIa (or blood-coagulation factor VIIa, activated blood coagulation factor VII), which in turn activates factor IX and factor X.
Using genetic recombination a recombinant factor VIIa (eptacog alfa) (trade names include NovoSeven) has been approved by the FDA for the control of bleeding in hemophilia.[5] It is sometimes used unlicensed in severe uncontrollable bleeding, although there have been safety concerns. A biosimilar form of recombinant activated factor VII (AryoSeven) is also available, but does not play any considerable role in the market.
In April 2020, the US FDA approved a new rFVIIa product, eptacog beta (SEVENFACT), the first bypassing agent (BPA) approved in more than 2 decades. As an rFVIIa product, eptacog beta works in a complex with tissue factor to activate factor X to Xa, thereby bypassing FVIII and FIX. The activation of Factor X to Xa initiates the coagulation cascade’s common pathway, leading to clot formation at the site of hemorrhage. Activated FVII binds to endothelial protein C receptor (EPCR), which enhances hemostasis.14 One study showed that eptacog beta binds to EPCR with 25% to 30% more affinity than eptacog alfa, displacing protein C from EPCR binding sites and downregulating activated protein C generation, contributing to its hemostatic effect.
Physiology
The main role of factor VII (FVII) is to initiate the process of coagulation in conjunction with tissue factor (TF/factor III). Tissue factor is found on the outside of blood vessels - normally not exposed to the bloodstream. Upon vessel injury, tissue factor is exposed to the blood and circulating factor VII. Once bound to TF, FVII is activated to FVIIa by different proteases, among which are thrombin (factor IIa), factor Xa, IXa, XIIa, and the FVIIa-TF complex itself. The complex of factor VIIa with TF catalyzes the conversion of factor IX and factor X into the active proteases, factor IXa and factor Xa, respectively.[6]
The action of the factor is impeded by tissue factor pathway inhibitor (TFPI), which is released almost immediately after initiation of coagulation. Factor VII, which was discovered around 1950, is vitamin K-dependent and produced in the liver. Use of warfarin or similar anticoagulants decreases hepatic synthesis of FVII.[citation needed]
A coagulation enzyme cascade may begin with a few molecules of factor XII and culminate in the activation of millions of times more fibrin molecules.[7]
Factor VII deficiency (congenital proconvertin deficiency) is rare and inherited recessively. It presents as a hemophilia-like bleeding disorder. It is treated with recombinant factor VIIa (NovoSeven or AryoSeven). Gene therapy approaches for treating FVII deficiency are very promising ([8])
Medical uses
Recombinant factor VIIa, marketed under the trade names AryoSeven and NovoSeven, is used for people with hemophilia (with Factor VIII or IX deficiency) who have developed antibodies against replacement coagulation factor.
It has also been used in the setting of uncontrollable hemorrhage,[9][10] but its role in this setting is controversial with insufficient evidence to support its use outside of clinical trials.[11] The first report of its use in hemorrhage was in an Israeli soldier with uncontrollable bleeding in 1999.[12] Risks of its use include an increase in arterial thrombosis.[11] However, animal studies have not shown complications as seen in humans, in fact same of the studies show a better prognosis. In the military settings it is used as an off label intervention in complications related to disseminated intravascular coagulation related haemorrhage caused by penetrating trauma.[13]
Recombinant human factor VII while initially looking promising in intracerebral hemorrhage failed to show benefit following further study and this is no longer recommended.[14][15]
^"Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
^"Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
^Biron-Andreani C, Schved JF (January 2019). "Eptacog beta: a novel recombinant human factor VIIa for the treatment of hemophilia A and B with inhibitors". Expert Review of Hematology. 12 (1): 21–28. doi:10.1080/17474086.2019.1560259. PMID30577721. S2CID58538425.
^Wajima T, Isbister GK, Duffull SB (September 2009). "A comprehensive model for the humoral coagulation network in humans". Clinical Pharmacology and Therapeutics. 86 (3): 290–298. doi:10.1038/clpt.2009.87. PMID19516255. S2CID205121835.
^ abSimpson E, Lin Y, Stanworth S, Birchall J, Doree C, Hyde C (March 2012). "Recombinant factor VIIa for the prevention and treatment of bleeding in patients without haemophilia". The Cochrane Database of Systematic Reviews. 3 (3): CD005011. doi:10.1002/14651858.CD005011.pub4. hdl:10871/13808. PMID22419303.
^Hodgetts TJ, Kirkman E, Mahoney PF, Russell R, Thomas R, Midwinter M (December 2007). "UK defence medical services guidance for the use of recombinant factor VIIa (rFVIIa) in the deployed military setting". Journal of the Royal Army Medical Corps. 153 (4): 307–309. doi:10.1136/jramc-153-04-18. PMID18619169. S2CID10776054.
^Mayer SA, Brun NC, Begtrup K, Broderick J, Davis S, Diringer MN, et al. (May 2008). "Efficacy and safety of recombinant activated factor VII for acute intracerebral hemorrhage". The New England Journal of Medicine. 358 (20): 2127–2137. doi:10.1056/NEJMoa0707534. hdl:10067/688040151162165141. PMID18480205.
^Zhang E, St Charles R, Tulinsky A (February 1999). "Structure of extracellular tissue factor complexed with factor VIIa inhibited with a BPTI mutant". Journal of Molecular Biology. 285 (5): 2089–2104. doi:10.1006/jmbi.1998.2452. PMID9925787.
Versteeg HH, Peppelenbosch MP, Spek CA (December 2001). "The pleiotropic effects of tissue factor: a possible role for factor VIIa-induced intracellular signalling?". Thrombosis and Haemostasis. 86 (6): 1353–1359. doi:10.1055/s-0037-1616734. PMID11776298. S2CID10976556.
1bf9: N-TERMINAL EGF-LIKE DOMAIN FROM HUMAN FACTOR VII, NMR, 23 STRUCTURES
1cvw: CRYSTAL STRUCTURE OF ACTIVE SITE-INHIBITED HUMAN COAGULATION FACTOR VIIA (DES-GLA)
1dan: COMPLEX OF ACTIVE SITE INHIBITED HUMAN BLOOD COAGULATION FACTOR VIIA WITH HUMAN RECOMBINANT SOLUBLE TISSUE FACTOR
1dva: Crystal Structure of the Complex Between the Peptide Exosite Inhibitor E-76 and Coagulation Factor VIIA
1f7e: THE FIRST EGF-LIKE DOMAIN FROM HUMAN BLOOD COAGULATION FVII, NMR, 20 STRUCTURES
1f7m: THE FIRST EGF-LIKE DOMAIN FROM HUMAN BLOOD COAGULATION FVII, NMR, MINIMIZED AVERAGE STRUCTURE
1fak: HUMAN TISSUE FACTOR COMPLEXED WITH COAGULATION FACTOR VIIA INHIBITED WITH A BPTI-MUTANT
1ff7: THE FIRST EGF-LIKE DOMAIN FROM HUMAN BLOOD COAGULATION FVII (FUCOSYLATED AT SER-60), NMR, 20 STRUCTURES
1ffm: THE FIRST EGF-LIKE DOMAIN FROM HUMAN BLOOD COAGULATION FVII (FUCOSYLATED AT SER-60), NMR, MINIMIZED AVERAGE STRUCTURE
1j9c: Crystal Structure of tissue factor-factor VIIa complex
1jbu: Coagulation Factor VII Zymogen (EGF2/Protease) in Complex with Inhibitory Exosite Peptide A-183
1kli: Cofactor-and substrate-assisted activation of factor VIIa
1klj: Crystal structure of uninhibited factor VIIa
1o5d: Dissecting and Designing Inhibitor Selectivity Determinants at the S1 site Using an Artificial Ala190 Protease (Ala190 uPA)
1qfk: STRUCTURE OF HUMAN FACTOR VIIA AND ITS IMPLICATIONS FOR THE TRIGGERING OF BLOOD COAGULATION
1w0y: TF7A_3771 COMPLEX
1w2k: TF7A_4380 COMPLEX
1w7x: FACTOR7- 413 COMPLEX
1w8b: FACTOR7 - 413 COMPLEX
1wqv: Human Factor Viia-Tissue Factor Complexed with propylsulfonamide-D-Thr-Met-p-aminobenzamidine
1wss: Human Factor Viia-Tissue Factor in Complex with peprid mimetic inhibitor that has two charge groups in P2 and P4
1wtg: Human Factor Viia-Tissue Factor Complexed with ethylsulfonamide-D-biphenylalanine-Gln-p-aminobenzamidine
1wun: Human Factor Viia-Tissue Factor Complexed with ethylsulfonamide-D-Trp-Gln-p-aminobenzamidine
1wv7: Human Factor Viia-Tissue Factor Complexed with ethylsulfonamide-D-5-propoxy-Trp-Gln-p-aminobenzamidine
1ygc: Short Factor VIIa with a small molecule inhibitor
1z6j: Crystal Structure of a ternary complex of Factor VIIa/Tissue Factor/Pyrazinone Inhibitor
2a2q: Complex of Active-site Inhibited Human Coagulation Factor VIIa with Human Soluble Tissue Factor in the Presence of Ca2+, Mg2+, Na+, and Zn2+
2aei: Crystal structure of a ternary complex of factor VIIa/tissue factor and 2-[[6-[3-(aminoiminomethyl)phenoxy]-3,5-difluro-4-[(1-methyl-3-phenylpropyl)amino]-2-pyridinyl]oxy]-benzoic acid
2aer: Crystal Structure of Benzamidine-Factor VIIa/Soluble Tissue Factor complex.
2b7d: Factor VIIa Inhibitors: Chemical Optimization, Preclinical Pharmacokinetics, Pharmacodynamics, and Efficacy in a Baboon Thrombosis Model
2b8o: Crystal Structure of Glu-Gly-Arg-Chloromethyl Ketone-Factor VIIa/Soluble Tissue Factor Complex
2bz6: ORALLY AVAILABLE FACTOR7A INHIBITOR
2c4f: CRYSTAL STRUCTURE OF FACTOR VII.STF COMPLEXED WITH PD0297121
2f9b: Discovery of Novel Heterocyclic Factor VIIa Inhibitors
2fir: Crystal structure of DFPR-VIIa/sTF
2flb: Discovery of a Novel Hydroxy Pyrazole Based Factor IXa Inhibitor
2flr: Novel 5-Azaindole Factor VIIa Inhibitors
2puq: Crystal structure of active site inhibited coagulation factor VIIA in complex with soluble tissue factor