METHOD FOR PRODUCTION OF A C1 ESTERASE INHIBITOR (C1-INH)-CONTAINING COMPOSITION

Abstract: A method is described for production of a C1-INH esterase inhibitor (C1-INH)-containing composition, which includes the following steps: treating a C1-INH-containing starting material with an anion exchanger under acidic conditions and eluting the C1-INH from the anion exchanger, in which a C1-INH-containing composition is obtained.

Description: METHOD FOR PRODUCTION OF A Cl ESTERASE INHIBITOR (Cl-INH)-CONTAINING COMPOSITION FIELD OF THE INVENTION: The invention concerns a method for production of a C l esterase inhibitor (C l -INH)-containing composition, as well as improved compositions containing C l -INH and Cl -INH-containing combination preparations. BACKGROUND OF THE INVENTION: Cl-INH is a plasma protease inhibitor which plays a central role in regulating the activation of complement and the kinin generation system. Cl -INH is the only inhibitor of C lr and Cl s in plasma, and is responsible for roughly half the kallikrein-activating activity and most of the blood coagulation factor XII inactivation. Cl-INH also inhibits blood coagulation factor XIa. Cl-INH consists of a single polypeptide chain with 478 amino acids and is synthesized with a 22 amino acid signal sequence. Based on sequence homology to the serpins, Cl-INH has been assigned to the serpin "superfamily" of serine protease inhibitors. In contrast to other proteases, especially from this family, or other proteins in blood plasma, Cl-INH has an extremely high degree of glycosylation. About 50% of the total weight of Cl -INH (about 105 kd) is composed of carbohydrates; the molecular weight of the peptide chain is approx. 53 kd. The isoelectric point of Cl -INH lies near 2.7 to 2.8 in the α 2 electrophoretic mobility determination. C 1 -INH can be produced for example, from human plasma or by using recombinant techniques. It was found that Cl-INH variants with nonphysiological glycosylation patterns (perhaps without N-glycosylation; by expression in hepatoma cell lines in the presence of tunicamycin) retain inhibitory activity, especially against Cls. Amino-terminally truncated Cl-INH molecules also exhibit unaltered activity relative to Cls, even though the main portion of the glycosylation sites lie in the amino terminal region (see Davis "Structure and Function of Cl Inhibitor," Behring Inst. Mitt.. 84 (1989), 142-150). Cl-INH is used in human medicine mostly because of its known inhibitory activity in the complement system. Thus, Cl-INH can moderate undesired pharmacological side effects. The addition of Cl-INH is therefore useful when applying protein preparations, which can exhibit side effects because of undesired pharmacologically active substances, in order to moderate the side effects. In this case, Cl -INH can be administered right before administration of the potentially side-effect-burdened preparation to the patient or in combination with the active principle being administered from biological sources, especially with plasma proteins or plasma derivatives (EP-0 1 19 990 Bl). Another important area of application of C 1 -INH is the treatment of hereditary or acquired angioedemas. Hereditary angioedema (HAE) is a rare, autosomal-dominant inheritable gynecotropic disease, which is characterized by a C 1 -INH deficiency or by formation of defective C 1 -INH. Acute attacks triggered by stressful situations occur frequently in HAE patients, with edematous swelling in the skin (mostly on the face and extremities) and mucosa. Serious abdominal colic can occur in edemas of the gastrointestinal mucosa. often connected with vomiting and diarrhea. The greatest hazard in HAE, however, results from attacks to the upper respiratory tract. Life-threatening asphyxiation attacks can occur in such laryngeal edemas. The high mortality of HAE (about 20 to 30%) essentially is attributed to the occurrence of such laryngeal edemas. HAE is mostly treated with Cl-INH, in addition to treatment with adrenalin, cortisone, danazol and ε-aminocaproic acid (see Mohr et al., Anaesthesist 45 (1996), 626-630. as well as Davis, Immunodeficiency Reviews 1 (1989), 207-226). In cases where acquired angioedemas are treated with C 1 -INH. mostly those angioedemas occuπing from C 1 -INH deficiency in the scope of tumors or autoimmune diseases are relevant (see Pschyrembel, "Klinisches Wόrterbuch," 257 th Edition, page 71). A number of methods have been proposed to produce Cl-INH-containing compositions from plasma, including, among others, affinity chromatography, ion exchange chromatography, gel filtration, precipitation, and hydrophobic interaction chromatography. It has been found, however, that C 1 -INH often cannot be adequately separated from its direct accompanying proteins with these methods (EP-0 101 935 Bl). Combinations of specific purification steps were therefore increasingly proposed in the prior art. A Cl-INH production method is described in EP-0 101 935 Bl. in which a Cl-INH-containing starting material is processed by a combination of precipitation steps and hydrophobic chromatography to produce a Cl-INH preparation, which was about 90% pure at a yield of about 20%. A combination of PEG precipitation and chromatography over jacalin-agarose and hydrophobic chromatography is proposed in US 5,030,578 A. A combination of ion exchange chromatography on DEAE groups, affinity chromatography using immobilized heparin, and treatment with a strong cation exchange gel was further proposed by Poulle et al. (Blood Coagulation and Fibrinolysis 5 (1994), 543-549; US 5,681,750 A). The Cl-INH preparation obtained with this method exhibits a specific activity of 6.5 ± 0.5 units/mg, but an antigen/activity ratio of only 1.7 to 2. In plasma, the antigen/activity ratio of 1 : 1. It was found according to the methods as described in the prior art, that either the accompanying proteins could not be separated efficiently enough from Cl-INH (mostly only albumin is insufficiently separable from Cl-INH with the described methods) or that satisfactory separation of these accompanying proteins at the expense of Cl-INH activity must be accepted, leading to an unsatisfactory specific activity or antigen/activity ratio in the obtained Cl-INH preparation. The provision of numerous chromatographic steps is also a shortcoming for the yield and activity of the obtained preparation, since both a loss of yield and a loss of activity must be tolerated with each chromatography step, for example, because of denaturation. SUMMARY OF THE INVENTION: The task of the present invention is therefore to prepare an improved method for production of a Cl-INH-containing composition, which permits simple and efficient separation of C 1 -INH-accompanying proteins, especially albumin, is applicable on an industrial scale, and can lead to improved C 1 -INH preparations in combination with already known process steps. This task is solved according to the invention by a method for production of a Cl-INH-containing composition that includes the following steps: -treating a C 1 -INH-containing starting material with an anion exchanger under acidic conditions, in which Cl-INH is bonded to the anion exchanger, and -treating Cl-INH from the anion exchanger, thereby determining a C 1 -INH-containing composition. The present invention is based on the surprising finding that treatment of Cl-INH-containing material with anion exchangers at an acid pH (i.e., below pH 7) leads to efficient separation of undesired accompanying proteins. Anion exchanger treatment has indeed long been known as a means of Cl-INH purification, but thus far adsorption of Cl-INH on an anion exchanger under acidic conditions has never been attempted. This circumstance is attributed to the fact that usual treatment with anion exchangers (not only for Cl-INH) is conducted at neutral or basic pH, since it is only in these ranges that anion exchange capacity is considered sufficient, primarily in purification methods on an industrial scale. However, it was found according to the invention that, precisely under acidic conditions, the bonding of C 1 -INH to the anion exchanger functions efficiently, and undesired accompanying proteins are not bonded and can be depleted. This is also surprisingly true for proteins, for example albumin, which like Cl-INH, have a low pi value. It turned out, surprisingly, that anion exchange chromatography can efficiently separate these proteins from Cl-INH, even at a pH that lies above the pi value of the proteins being eliminated. The Cl-INH-containing starting material is preferably treated with the anion exchanger at a pH value of 3.0 to 6.9, preferably pH 4.5 to 6. At pH values of 7.0 and higher, the effects according to the invention, especially efficient separation of accompanying proteins with low pi values, no longer occur satisfactorily. At pH values less than 3.0, the invention can be performed in principle, but the risk of denaturation losses of acid-labile proteins or other materials used during purification must then be tolerated. An ionic strength of 30 mS (0.5M NaCl) or higher is preferably used during adsorption. Since the Cl-INH preparation obtained with the present invention is to be used mostly pharmaceutically, at least one additional step for inactivation of potentially present viruses is provided in the method according to the invention. This can occur before, during, or after the anion exchange step. Appropriate virus inactivation steps are generally known. They include chemical, chemical-physical, and physical methods. Methods using virucidal substances can also be employed during and after a chromatographic purification method. At least two measures are preferably provided that cause inactivation or depletion of human pathogenic infection producers, including viruses transmittable by blood, like HIV, HAV, HBV, HCV, HGV and parvo viruses, but also the infectious pathogens of BSE and CJD. Effective measures for inactivation of viruses include, for example, treatment with organic solvents and/or detergents (EP-0 131 740 A, EP-0 050 061 A, WO98/44941 A), treatment with chaotropic agents (WO90/15613 A), heat treatment methods, preferably in the lyophilized, dry, or moist state (EP-0 159 311 A), combination methods (EP-0 519 901 A), and physical methods. The latter cause viral inactivation, for example, by irradiation with light, perhaps in the presence of photosensitizers (EP-0 471 794 A and WO-97/3768 A). Depletion methods for human pathogens using ultrafilters, low-pass filters, and especially nanofilters, are particularly prefeπed according to the invention (WO97/40861 A, 4998/57672 A), but precipitation steps and other protein purification measures, like adsorption, also contribute, in principle, to depletion of any pathogens that might be present. The nanofiltration particularly preferred according to the invention is preferably conducted so that the Cl-INH-containing composition is diluted before the nanofiltration step. Problems that can occur from the relatively high molecular weight of Cl-INH, and can lead, for example, to clogging of the filter pores, are avoided from the outset on this account. Nanofiltration is preferably conducted within the scope of the method according to the invention after anion exchange chromatography, and preferably with filters that have a pore size from 10 to 40 nm. Any Cl-INH-containing material is suitable in principle as Cl-INH-containing material. However, plasma, cryosupematant, Cl-INH-containing Cohn fractions, Cl-INH-containing cell culture supernatants, transgenically produced Cl-INH-containing material, or a prepurified Cl-INH preparation are preferably used. The prepurified Cl-INH preparation can then be obtained by a method already described in the prior art before it is subjected, according to the invention, to the anion exchange step under acidic conditions. Even further improved purification results can be achieved according to the invention by repeating the anion exchange step under acidic conditions. The pH of the obtained solution is then optimally brought to an acid value again, but then brought in contact with an anion exchanger, in which Cl-INH is bonded again. As in the first anion exchange treatment, the adsorbed Cl-INH can also be subjected to one or more washing steps before being eluted again from the anion exchanger. The Cl-INH-containing composition obtained after elution can, in addition to the prefeπed retreatment with the anion exchange step according to the invention, also be purified further using other methods. The additional purification steps prefeπed according to the invention include those steps whose essential effectiveness has already been described in the prior art with respect to Cl-INH, like precipitation (with PEG, ammonium sulfate. etc.), hydrophobic chromatography. especially over phenylsepharose, affinity chromatography, especially over heparin sepharose or jacalin-agarose, or cation exchange chromatography. All anion exchangers that have an affinity to C 1 -INH can be considered as anion exchangers in principle, like anion exchangers based on cellulose (Whatman' 1 ' DE52, QAE52, Express Ion ® Q and D, all from the Whatman company) with diethylaminoethyl groups (DEAE-Sephacel ® ), anion exchangers based on crosslinked dextran with diethylaminoethyl groups (DEAE-Sephadex ® ), anion exchangers based on agarose with diethylaminoethyl groups (DEAE-Sepharose CL6B ® , DEAE-Sepharose Fast Flow ® ), anion exchangers based on crosslinked dextran with diethyl[2-hydroxypropyl]aminoethyl groups (QAE-Sephadex ® ), anion exchangers based on agarose with CH 2 N + (CH ) 3 groups (Q-Sepharose Fast Flow ® , Q-Sepharose High Performance ® , Q-Sepharose Big Beads' ) (all from Pharmacia), spherical chromatography gels produced by copolymerization of N-acryloyl-2-amino-2-hydroxymethyl-l ,3-propanediol and an anionic acrylic derivative with diethylaminoethyl groups as functional anion exchangers (DEAE-Tris-Acryl ® ), noncompressible silica-dextran matrices, in which porous silica gel is embedded in a crosslinked dextran matrix, with reactive diethylaminoethyl anion exchanger groups (DEAE-Spherodex ® ), gels from rigid polystyrene particles, whose pores are filled with a hydrogel carrying quaternary amino groups with strong anion exchange effects (Q-Hyer-D H ) (all from Sepracor); rigid macroporous hydrophilic surfaces with N + (C 2 H 5 ) 2 or N + (CH 3 ) groups (Macroprep DEAE* , Macroprep Q ® ) (all from BioRad); anion exchangers with diethylamino-diethyl(2-hydroxypropyl)aminoethyl and CH 2 N + (CH 3 ) 3 groups (DEAE-Toyopearl ® , QAE-Toyopearl ® , Toyopearl SuperQ ® ) (all from Tosohaas); anion exchange resins, consisting of porous polymethacrylate/polyacrylate gel (Protein PAK DEAE ® from the Waters company); anion exchangers based on copolymers consisting of oligoethylene glycol dimethacrylate, glycidyl methacrylate and pentaerythritol dimethacrylate with a hydrophobic surface (Fractoge EMD-TMAE ® , Fractogel EMD-DEAE ® , Fractogel EMD-DMAE ® ), and anion exchangers based on silica with porous spherical pressure-stable chromatography particles (Licrospher 1000 TMAE ® , Licrospher 1000 DEAE ® and Licrospher 4000 DMAE ® ) (all from Merck). According to the invention, anion exchanger materials, like DEAE-Sephadex ® . QAE-Sephadex ® A50 or Toyopearl Super-Q ® 650C, as well as Whatman ® DE52, QAE52, Express Ion ® Q and D, are particularly preferred. The purified Cl-INH compositions obtained are preferably lyophilized and optionally subjected to (additional) virus-inactivation treatment. Heat treatment, especially in the temperature range between 60 and 100°C over a period from 10 to 80 h, is preferred here according to the invention. For use as pharmaceutical agents, the obtained Cl-INH composition (lyophilized or in solution) is prepared to a pharmaceutical preparation and packed in the coπesponding containers. Both stabilizers and other auxiliaries and/or other active components (to produce a combination preparation) can then be mixed with the Cl-INH-containing composition, as according to EP-0 480 906 A, where lys-plasminogen is administered, combined with Cl-INH. A particularly preferred variant of the method according to the invention is characterized by the sequence of the following steps: -treating a C 1 -INH-containing starting material with an anion exchanger under acidic conditions, in which Cl-INH is bonded to the anion exchanger, -optional washing of the adsorbed Cl-INH-containing material, -eluting the C 1 -INH from the anion exchanger, in which a C 1 -INH-containing eluate is recovered, -treating the Cl-INH-containing eluate with PEG, preferably with PEG 4000, especially in amounts of less than 15%, in which a precipitate and a C 1 -INH-containing supernatant are obtained, -treating the Cl-INH-containing supernatant with a detergent, in which any viruses present are inactivated, -treating the detergent-containing C 1 -INH-containing supernatant with an anion exchanger, in which Cl-INH is bonded again and the detergent and any contaminant still present are removed, -optional washing of the bonded Cl-INH-containing material, -eluting the Cl-INH from the anion exchanger, in which a virus-inactivated Cl-INH-containing eluate is obtained, -nano filtrating of this eluate, -lyophilizing of the nanofiltered Cl-INH solution, and -heat treating of the lyophilized Cl-INH-containing composition. Elution from the anion exchanger preferably occurs with a buffer having a salt concentration higher than the salt concentration in the adsorption step, the best results being achieved with salt concentrations that lie at least 3 times higher than that of the adsorption solution. The washing step of the adsorbed Cl-INH is preferably conducted with the adsorption buffer, or a buffer that coπesponds roughly to the adsorption buffer, especially in terms of conductivity. The salt concentration of the washing buffer preferably lies no more than 10 to 100% above that of the adsorption solution. According to another aspect, the present invention concerns Cl-INH-containing compositions characterized by the fact that they have a specific activity of 2.0 units/mg of protein or more at an antigen/activity ratio of less than 1.5. As also demonstrated in the examples, the method according to the invention can lead to highly purified preparations in this way. In the prior art, Cl-INH-containing compositions have already been obtained with a specific activity of higher than 2 units/mg of protein or with an antigen/activity ratio of less than 1.5, but the combination of this degree of purification could never previously be achieved, since as already described, the increased specific activity always occuπed at the expense of the antigen/activity ratio, or an improved antigen/activity ratio could never be achieved with such high specific activities. Compositions with a specific activity of 4 to 8, especially 5 to 7, units/mg of protein are attainable without difficulty according to the invention. Antigen/activity ratios from 1 to 1.4, especially 1.1 to 1.3, are attainable simultaneously. The preparations according to the invention are preferably present as pharmaceutical preparations in packaged form and are optionally virus-inactivated. According to another aspect, the present invention concerns combination preparations that include a C 1 -INH-containing composition according to the invention with at least one additional pharmaceutically active substance (similar to the drugs described in EP-0 119 990 Bl and EP-0 480 906 A). The invention is further explained by means of the following example: EXAMPLE: 2.5 g of dry QAE-Sephadex A50 ® is equilibrated with a Cl-INH solution (1000 IU Cl-INH (one international unit (IU) or unit (U) of Cl-INH coπesponds to the Cl-INH activity in 1 mL of fresh plasma), 100 mM sodium acetate, 50 mM sodium chloride, pH 5.5) and the pH set at 5.5. Adsorption is carried out for 2 h at 4°C. The gel with the adsorbed Cl-INH is then washed with: a) 100 mM sodium acetate and 50 mM sodium chloride, pH 5.5, and b) 20 mM Tris and 200 mM sodium chloride, pH 7.5. It is eluted with 20 mM Tris and 750 mM sodium chloride, pH 7.5. The obtained Cl-INH solution is brought back to a pH of 5.5, and PEG 4000 is added to a final concentration of 12% (w/w). It is precipitated for 1 h at 4°C and then centrifuged, in which the precipitate is discarded. 12.5% Tween 80 ® (w/w) is added to the supernatant and agitated for 4 h at 35°C. This Tween 80 ® -containing solution or suspension is equilibrated with 10 mM sodium acetate and 50 mM sodium chloride, pH 5.5, in which about 20 IU Cl-INH per mL of gel is adsorbed. The adsorbed gel is then washed with a) 10 mM sodium acetate and 50 mM sodium chloride, pH 5.5, b) 154 mM NaPO 4 buffer at pH 5.5, and c) 10 mM Tris and 100 mM sodium chloride at pH 7.0. Elution is conducted with a solution containing 10 mM Tris and 250 mM sodium chloride at pH 7.0. The obtained eluate is nanofiltered with an Asahi Planova 15N filter; the nanofiltered solution is then ultra/diafiltered. The obtained solution is standardized at the desired concentration (50, 100 or 200 international units per mL). 1 g/L sodium citrate, 1 g/L trehalose, and 9 g/L sodium chloride are provided in the buffer. This preparation is lyophilized to a moisture content of less than 1.5% and heated in the final containers to at least 80°C for at least 72 h. The results are shown in the following table: Table The end product so obtained has an antigen/activity ratio of 1.15: 1.

Claims: What is claimed is: I . A method for production of a C 1 -INH esterase inhibitor (C 1 -INH)-containing composition, including the following steps: - treating a Cl-INH-containing starting material with an anion exchanger under acidic conditions and - eluting the Cl-INH from the anion exchanger, in which a Cl-INH-containing composition is obtained. 2. The method according to claim 1 , wherein the treatment of the starting material with the anion exchanger is conducted at a pH from 3.0 to 6.9. 3. The method according to claim 2, wherein the anion exchange is contacted at a pH from 4.5 to 6. 4. The method according to claim 1. wherein at least one additional step for inactivation of potentially present viruses is conducted. 5. The method according to claim 1, wherein plasma, cryosupernatant, Cl-INH-containing Cohn fractions, Cl-INH-containing cell culture supernatants, transgenically produced Cl-INH-containing material, or a prepurified Cl-INH preparation is used as starting material. 6. The method according to claim 1 , wherein the composition obtained after elution is brought in contact with an anion exchanger again, in which the Cl-INH is bonded, the bonded Cl-INH is optionally subjected to at least one washing step, and eluted again. 7. The method according to claim 1, wherein the composition obtained after elution is subjected to at least one additional purification step. 8. The method according to claim 7, wherein the purification step is PEG precipitation, hydrophobic chromatography, affinity chromatography or cation exchange chromatography. 9. The method according to claim 1 additionally comprising the step of lyophilizing said C 1 -INH-containing composition. 10. The method according to claim 9, wherein the lyophilized composition is subjected to heat treatment. I I . The method according to claimlO, wherein the heat treatment is in a temperature range between 60°C and 100°C over a period from 10 to 80 h. 12. The method according to claim 1, wherein the obtained composition is prepared as a pharmaceutical preparation. 13. The method for production of a Cl -INH-containing composition comprising the following steps: -treating a C 1 -INH-containing starting material with an anion exchanger under acidic conditions, in which Cl-INH is bonded to the anion exchanger, -eluting the C l-INH from the anion exchanger, in which a Cl-INH-containing eluate is recovered, -treating the Cl-INH-containing eluate with PEG, especially in an amount of less than 15%, in which a precipitate and a Cl-INH-containing supernatant are obtained, -treating the C 1 -INH-containing supernatant with a detergent, in which any viruses present are inactivated, -treating the detergent-containing C 1 -INH-containing supernatant with an anion exchanger, in which Cl-INH is bonded again, and the detergent and any contaminants still present are removed, -optional washing of the bonded Cl-INH-containing material, -eluting of the Cl-INH from the anion exchanger, in which a virus-inactivated C 1 -INH-containing eluate is obtained, -nanofiltrating of this eluate, -lyophilizing the nanofiltered Cl-INH solution, and -heat treating of the lyophilized Cl-INH-containing composition. 14. The method according to claim 13, wherein the Cl-INH containing material adsorbed to the anion exchanger is washed. 15. A Cl-INH-containing composition having a specific activity of 2.0 U/mg of protein or more at an antigen/activity ratio of less than 1.5. 16. The Cl-INH-containing composition according to claim 15 having a specific activity of 4 to 8 U/mg of protein. 17. The Cl-INH containing composition according to claim 15 having a specific activity of 5 to 7 U/mg of protein. 18. The Cl-INH-containing composition according to claim 15 having an antigen/activity ratio of 1 to 1.4. 19. The Cl-INH containing composition according to claim 15 having an antigen/activity ratio of 1.1 to 1.3. 20. The Cl-INH-containing composition obtained by the method of claim 1 , wherein said composition is present as a pharmaceutical preparation. 21. A Cl-INH-containing composition obtained by the method of claim 4. 22. A combination preparation according to claim 15, and at least one additional pharmaceutically active substance, selected from the group consisting of plasma protein or plasma derivative.

Inventors: LINNAU YENDRA, SCHOENHOFER WOLFGANG, SCHWARZ HANS-PETER, ZOECHLING OLIVER, LINNAU, YENDRA, SCHOENHOFER, WOLFGANG, SCHWARZ, HANS-PETER, ZOECHLING, OLIVER
Applicants: BAXTER AG, BAXTER AKTIENGESELLSCHAFT
Application year: 2000
Main classification: C07K1
IPC codes: A61K38, C07K14