"Improved Factor Viii Preparations Suitable for Therapeutic Use and Processes to Obtain These" in Patent Application Approval Process (USPTO 20170209546)
By a News Reporter-Staff News Editor at Obesity, Fitness & Wellness Week A patent application by the inventors SCHMIDBAUER, Stefan (Lahntal, DE); METZNER, Hubert (Marburg, DE); ROBBEL, Lars (Wetter, DE), filed on July 24, 2015, was made available online on August 3, 2017, according to news reporting originating from Washington, D.C., by NewsRx correspondents (see also Pharmaceutical Companies).
This patent application is assigned to Csl Behring Gmbh.
The following quote was obtained by the news editors from the background information supplied by the inventors: "There are various bleeding disorders caused by deficiencies of blood coagulation factors. Some of the most common bleeding disorders are hemophilia A and B, resulting from deficiencies of blood coagulation Factor VIII and IX, respectively.
"Classic hemophilia or hemophilia A is an inherited bleeding disorder. It results from a chromosome X-linked deficiency of blood coagulation Factor VIII, and affects almost exclusively males with an incidence of between one and two individuals per 10.000. The X-chromosome defect is transmitted by female carriers who are not themselves hemophiliacs. The clinical manifestation of hemophilia A is an increased bleeding tendency. Before treatment with Factor VIII concentrates was introduced the mean life span for a person with severe hemophilia was less than 20 years. The use of concentrates of Factor VIII from plasma has considerably improved the situation for the hemophilia A patients increasing the mean life span extensively, giving most of them the possibility to live a more or less normal life. However, there have been certain problems with the plasma derived concentrates and their use, the most serious of which have been the transmission of viruses. So far, viruses causing hepatitis B, non-A non-B hepatitis and AIDS have hit the population seriously. Since then different virus inactivation methods and new highly purified Factor VIII concentrates have been developed which established a very high safety standard also for plasma derived Factor VIII.
"The cloning of the cDNA for Factor VIII (Wood et al. 1984. Nature 312:330-336; Vehar et al. 1984. Nature 312:337-342) made it possible to express Factor VIII recombinantly leading to the development of several recombinant Factor VIII products, which were approved by the regulatory authorities between 1992 and 2003. The fact that the central B domain of the Factor VIII polypeptide chain residing between amino acids Arg-740 and Glu-1649 does not seem to be necessary for full biological activity has also led to the development of B domain deleted Factor VIII products.
"The mature wild-type Factor VIII molecule consists of 2332 amino acids which can be grouped into three homologous A domains, two homologous C domains and a B Domain which are arranged in the order: A1-A2-B-A3-C1-C2. The complete amino acid sequence of mature human Factor VIII is shown in SEQ ID NO:2. The A domains also comprise acidic regions highlighted as a1, a2, and a3 (FIG. 1). During its secretion into plasma Factor VIII is processed intracellularly into a series of heterodimers of different length which are associated by metal-ions as single chain Factor VIII is cleaved at the B-A3 boundary and at different sites within the B-domain. This processing leads to heterogeneous heavy chain molecules consisting of the A1, the A2 and various parts of the B-domain which have a molecular size ranging from 90 kDa to 200 kDa and to light chain molecules which have a molecular size of about 80 kDa. One heavy chain is bound non-covalently via a metal ion bridge to one light chain, which consist of the A3, the C1 and the C2 domain (Saenko et al. 2002. Vox Sang. 83:89-96). In plasma this heterodimeric Factor VIII binds with high affinity to von Willebrand Factor, which protects it from premature catabolism. The half-life of non-activated Factor VIII bound to vWF is about 12 hours in plasma.
"Coagulation Factor VIII is activated via proteolytic cleavage by FXa and thrombin at amino acids Arg372 and Arg740 within the heavy chain and at Arg1689 within the light chain resulting in the release of von Willebrand Factor and generating the activated Factor VIII heterotrimer which will form the tenase complex on phospholipid surfaces with FIXa and FX provided that Ca.sup.2+ is present. The heterotrimer consists of the A1 domain, a 50 kDa fragment, the A2 domain, a 43 kDa fragment and the light chain (A3-C1-C2), which is a fragment of about 80 kDa. Thus the active form of Factor VIII (Factor Villa) consists of an A1-subunit associated through the divalent metal ion linkage to a thrombin-cleaved A3-C1-C2 light chain and a free A2 subunit relatively loosely associated with the A1 and the A3 domain.
"Due to the introduction of virus inactivation and elimination steps in the production processes of plasma derived and recombinant Factor VIII concentrates the virus safety of these products is very high. Therefore, the most serious side effect of Factor VIII treatment nowadays is the development of inhibitory antibodies to Factor VIII. This may result in the neutralization of the administered Factor VIII concentrate leading sometimes to life-threatening bleeding episodes. It has been described that in the treatment of hemophilia A the risk of the patient to develop an inhibitor throughout its life is in the range of about 25-30%.
"There is, therefore, an unmatched clinical need to provide Factor VIII products, i.e. recombinant Factor VIII products with a reduced immunogenicity.
"It has been described, that the risk of inhibitor generation in previously untreated patients with Haemophilia A is higher when treated with recombinant Factor VIII products, and it has been speculated that the binding of vWF to different epitopes in the FVIII-LC (A3 and C2 domains) shields these epitopes and might therefore have an beneficial effect in reducing immunogenicity (C. Escuriola Ettinghausen, W. Kreuz; Haemophilia (2006), 12, (Suppl. 6), 102-106). Unshielded epitopes of Factor VIII appears to pose a risk of triggering the generation of inhibitors. In addition, the interaction of the FVIII-HC and the FVIII-LC in the two-chain FVIII complex is assumed to also have a shielding effect on otherwise freely accessible epitopes in the FVIII-HC and the FVIII-LC.
"The isolation of Factor VIII from human plasma (pdFVIII) or the recombinant production of Factor VIII (rFVIII) nowadays are well-known procedures to provide Haemophilia A patients with the corresponding concentrates for treatment. However, during manufacturing these Factor VIII products are subjected to unphysiologic conditions which may result in damage and partial inactivation. This may be caused by proteolytic inactivation or by chemical or structural modification. Such structural modifications as e.g. the disruption of the interaction of the different domains may be triggered by loss of stabilizing metal ions or by contact to foreign surfaces. In WO 97/33178 it has been described that proteolytic Factor VIII fragments in a molecular weight range between 20 and 50 kDa in a pharmaceutical Factor VIII preparation may be critical for giving rise to inhibitor formation and a process was described using size exclusion chromatography (SEC) where Factor VIII fractions containing such fragments are separated to obtain a Factor VIII product with a lower content of these fragments and thus lower immunogenicity. However, WO 97/33178 did not mention the separation of the Factor VIII preparation from Factor VIII fragments larger than 50 kDa. U.S. Pat. No. 4,675,385, EP0321835, EP0399321 and EP0410207 describe the use of size exclusion chromatography for the preparation of Factor VIII but none of these patents describes the presence nor the specific removal of non-associated Factor VIII heavy chains (FVIII-HCs) or of non-associated Factor VIII light chains (Factor VIII-LCs). Native SEC was also used to analyze various commercially available Factor VIII preparations (Jankowski et al., Haemophilia (2007), 13, 30-37) but it was not recognized that non-associated FVIII-HCs or non-associated FVIII-LCs were present in these preparations.
"It has now surprisingly been found that all tested commercially obtainable pharmaceutical two-chain Factor VIII preparations do comprise some amount of non-associated FVIII-LCs. As in intact Factor VIII molecules the FVIII-HCs are associated with FVIII-LCs in a metal-dependent association these non-associated FVIII-LCs do expose epitopes which are normally shielded in the metal-dependent association with FVIII-HCs and their presence in a pharmaceutical Factor VIII preparation does thus increase the risk that such Factor FVIII preparations are immunogenic. Probably in these tc-FVIII preparations also more or less FVIII-HCs which are non-associated with FVIII-LC are present and do then also pose a risk of being immunogenic. In pharmaceutical single-chain Factor VIII preparations as described in WO 2004/067566 such non-associated FVIII-HCs and FVIII-LCs will be presentif at allin a much lower amount as there is a covalent linkage between the FVIII-HC and the FVIII-LC. However also in single-chain Factor VIII preparations there is a minority of molecules which are cleaved between the FVIII-HC and the FVIII-LC and thus this minority of tc-FVIII molecules may become partly separated into non-associated FVIII-HCs and non-associated FVIII-LCs. The invention is thus directed to pharmaceutical two-chain Factor VIII preparations with low amounts of non-associated FVIII-HCs and/or low amounts of non-associated-FVIII-LCs, methods to test the suitability of therapeutic Factor VIII preparations and to methods to reduce the amount of non-associated FVIII-HCs and/or non-associated FVIII-LCs in pharmaceutical Factor VIII preparations."
In addition to the background information obtained for this patent application, NewsRx journalists also obtained the inventors' summary information for this patent application: "The invention is directed to pharmaceutical preparations comprising two-chain Factor VIII (tc-FVIII) that are essentially free of Factor VIII Light Chains (FVIII-LCs) which are non-associated with Factor VIII Heavy Chains (FVIII-HCs).
"One embodiment of the invention are pharmaceutical preparations comprising a tc-FVIII wherein less than 0.9% of all FVIII-LCs within said preparation are non-associated with FVIII-HCs.
"In one embodiment of the invention the tc-FVIII is a full-length Factor VIII, which may be of plasmatic or of recombinant origin.
"In specific embodiments of full-length FVIII molecules the molecular weight of the non-associated FVIII-LCs is about 70 to 125 kDa, preferably about 80 kDa.
"In another embodiment the tc-FVIII is a B-domain truncated Factor VIII.
"In specific embodiments of B-domain truncated FVIII molecules the molecular weight of the non-associated FVIII-LC is about 70 to 125 kDa, preferably about 80 kDa.
"Other embodiments of the invention are directed to pharmaceutical preparations of tc-FVIII wherein the pharmaceutical preparations are less immunogenic as compared to pharmaceutical preparations comprising tc-FVIII wherein 0.9% or more of all FVIII-LCs within said preparation are non-associated with FVIII-HCs.
"Certain embodiments of the invention relate to the use of the above preparations in medicine, preferably to the use in the treatment of hemophilia A.
"The invention also relates to a method for testing the suitability of a preparation comprising Factor VIII for therapeutic use comprising a step of determining the amount of i) FVIII-HCs which are non-associated with FVIII-LCs and/or ii) FVIII-LCs which are non-associated with FVIII-HCs.
"Preferably preparations comprising Factor VIII comprising i) more than a predefined maximal amount of all FVIII-HCs which are non-associated with FVIII-LCs and/or ii) more than a predefined maximal amount of all FVIII-LCs which are non-associated with FVIII-HCs
"are subjected to a further purification step, preferably by SEC, decreasing the amount of non-associated FVIII-HCs and/or non-associated FVIII-LCs.
"The predefined maximal amount may be defined as i) more than 0.1% of all FVIII-HCs within said preparation are non-associated with FVIII-LCs and/or ii) more than 0.1% of all FVIII-LCs within said preparation are non-associated with FVIII-HCs.
"The invention also relates to a method for preparing a pharmaceutical preparation of Factor VIII comprising i) starting from a composition comprising Factor VIII and which comprises FVIII-HCs within said starting composition which are non-associated with FVIII-LCs and then reducing the amount of FVIII-HCs which are non-associated with FVIII-LCs to an amount of less than 50% of the amount in the starting composition and/or ii) starting from a composition comprising Factor VIII and which comprises FVIII-LCs within said starting composition which are non-associated with FVIII-HCs and then reducing the amount of FVIII-LCs which are non-associated with FVIII-HCs to an amount of less than 50% of the amount in the starting composition.
"The invention also relates to a method for preparing a pharmaceutical preparation of Factor VIII comprising i) starting from a composition comprising Factor VIII wherein at least 0.1% of all FVIII-HCs within said starting composition are non-associated with FVIII-LCs and then reducing the amount of FVIII-HCs which are non-associated with FVIII-LCs to an amount of less than 50% of the amount in the starting composition and/or ii) starting from a composition comprising Factor VIII wherein at least 0.1% of all FVIII-LCs within said starting composition are non-associated with FVIII-HCs and then reducing the amount of FVIII-LCs which are non-associated with FVIII-HCs to an amount of less than 50% of the amount in the starting composition.
"The invention also relates to a method for preparing a pharmaceutical preparation of Factor VIII comprising i) starting from a composition comprising Factor VIII wherein at least 0.9% of all FVIII-HCs within said starting composition are non-associated with FVIII-LCs and then reducing the amount of FVIII-HCs which are non-associated with FVIII-LCs to an amount of less than 50% of the amount in the starting composition and/or ii) starting from a composition comprising Factor VIII wherein at least 0.9% all FVIII-LCs within said starting composition are non-associated with FVIII-HCs and then reducing the amount of FVIII-LCs which are non-associated with FVIII-HCs to an amount of less than 50% of the amount in the starting composition.
"In one embodiment the method for preparing a pharmaceutical preparation of tc-FVIII involves SEC."
URL and more information on this patent application, see: SCHMIDBAUER, Stefan; METZNER, Hubert; ROBBEL, Lars. Improved Factor Viii Preparations Suitable for Therapeutic Use and Processes to Obtain These. Filed July 24, 2015 and posted August 3, 2017. Patent URL: http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220170209546%22.PGNR.&OS=DN/20170209546&RS=DN/20170209546
Keywords for this news article include: Antigens, Pharmaceutical Companies, Plasma, Epitopes, Genetics, Peptides, Hepatitis, Hematology, Immunology, Amino Acids, Factor VIII, Hemophilia A, Therapeutics, Blood Proteins, Csl Behring Gmbh, Gastroenterology, Biological Factors, Virus Inactivation, Risk and Prevention, Von Willebrand Disease, Blood Coagulation Factors.
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