Chemistry: natural resins or derivatives; peptides or proteins; – Proteins – i.e. – more than 100 amino acid residues – Blood proteins or globulins – e.g. – proteoglycans – platelet...
Reexamination Certificate
1999-05-20
2002-08-27
Brumback, Brenda (Department: 1642)
Chemistry: natural resins or derivatives; peptides or proteins;
Proteins, i.e., more than 100 amino acid residues
Blood proteins or globulins, e.g., proteoglycans, platelet...
Reexamination Certificate
active
06441144
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an integral, multi-step commercial process for the production of intravenously administrable immune globulin containing IgG (&ggr;-globulin) as the main ingredient.
Various processes are known for obtaining intravenously administrable &ggr;-globulin solutions from starting materials resulting from Cohn fractionation of human plasma. Certain of the Cohn fractions contain higher titres of &ggr;-globulin than others. Usual starting materials for a &ggr;-globulin solution are Cohn Fraction II or Cohn Fraction II+III.
Although prior art processors employ various separation and sterilization techniques, process modifications are constantly sought for improving final product purity and safety, and overall yield.
Many commercial processes employ either a solvent/detergent step for viral inactivation, or a heat treatment step for viral inactivation. To date, the art has not provided a multi-step process beginning with Cohn Fraction II paste or II+III paste including two different viral inactivation procedures as part of an efficient, high yield &ggr;-globulin manufacturing process.
U.S. Pat. No. 5,151,499 by Kameyama et al. is directed to a process for producing viral inactivated protein compositions in which a protein composition is subjected to a viral inactivation for envelope viruses in a solvent/detergent treatment of the protein composition and a viral inactivation for non-envelope viruses in a heat treatment of the protein composition. The '499 patent teaches that preferably the solvent/detergent step occurs first and in the presence of a protease inhibitor, followed by a heat treatment, which in most examples thereof is a dry heat treatment. Where the heat treatment is carried out in the liquid state, the protein is first recovered from the solvent/detergent by adsorption onto an ionic exchange column, prior to any heat treatment. The liquid heat treatment can be carried out in the presence of a sugar, sugar alcohol or amino acid stabilizer. Although the '499 patent lists many starting protein compositions including immunoglobulin, its production examples employ Factor VIII, Factor IX, thrombin, fibrinogen and fibronectin.
U.S. Pat. No. 5,371,196 by Uuki et al. is directed to purifying secretory immunoglobulin A. A liquid heat treatment or various combinations of liquid heat treatment and solvent treatment viral inactivation are described. A polyethylene glycol fractionation is employed following each step and always as a final step. This patent does not relate to immune serum globulin of high &ggr;-globulin titre.
Certain prior art processes for production of intravenously injectable &ggr;-globulin solutions describe the incorporation of a liquid heat treatment carried out in the presence of sorbitol heat stabilizer in a multi-step purification procedure beginning with Cohn Fraction II +III paste. In U.S. Pat. No. 4,845,199 by Hirao et al., Cohn Fraction II+III is subjected to polyethylene glycol (hereinafter “PEG”) fractionation (8% w/v PEG for precipitating impurities and aggregate followed by 12% w/v PEG for precipitating the &ggr;-globulin), then ion exchange chromatography (DEAE-SEPHADEX®, Pharmacia, anion exchanger) and removal of human blood group antibody prior to a liquid heat treatment in the presence of sorbitol as a protein stabilizer. On the other hand, Example 1 of U.S. Pat. No. 4,876,088 by Hirao et al. describes the preparation of intravenously injectable &ggr;-globulin solution from Cohn Fraction II+III paste in which the paste is suspended in water, its pH adjusted to 5.5 and centrifuged, with the supernatant then being heat treated for viral inactivation in the presence of 33% w/v of sorbitol, followed by PEG fractionation (6%/12%), and then by other purification steps including DEAE-Sephadex ion exchange chromatography.
SUMMARY OF THE INVENTION
An object of the present invention is to provide an integral, commercially useable process for producing a highly purified &ggr;-globulin solution from the Cohn fractionation process.
Another object of the present invention is to provide very pure intravenously administrable &ggr;-globulin solution free of both envelope and non-envelope viruses, including all heat sensitive viruses.
A further object of the present invention is to provide a commercial &ggr;-globulin process including two sequential viral inactivation steps without the need for recovery of &ggr;-globulin protein following the first viral inactivation step nor prior to the second viral inactivation step.
The above and other objects which will be apparent to the skilled artisan are provided by the present invention in which an alcoholic Cohn fraction, which may be partially purified, but is rich in &ggr;-globulin, is first subjected to PEG fractionation, and then to two viral inactivation treatments, one being a viral inactivation in the presence of a solvent, preferably a solvent-detergent mixture, for disruption of envelope viruses, and the other being a heat treatment viral inactivation, without recovery of &ggr;-globulin between the two viral inactivations. Then, any aggregate formed by the heat treatment is removed from the heat treated and solvent treated solution.
In a preferred embodiment of the present invention, sorbitol is the heat stabilizer and trialkyl phosphate is the solvent.
In another embodiment of the present invention, any particulates present are removed prior to the solvent-detergent treatment.
In another embodiment of the present invention, the &ggr;-globulin solution is subjected to PEG fractionation following the completion of viral inactivation.
In yet another embodiment of the present invention, the &ggr;-globulin solution is treated with a cationic exchange resin following the completion of viral inactivation.
In certain preferred embodiments of the present invention a single stage polyethylene glycol fractionation step is carried out without precipitation of the &ggr;-globulin.
In another preferred embodiment of the invention, solvent-detergent viral inactivation is carried out before the heat treatment viral inactivation.
In still another embodiment of the invention, there is provided a heat-sterilized and solvent-detergent sterilized &ggr;-globulin suitable for intravenous administration.
DETAILED DESCRIPTION OF THE INVENTION
A fraction containing immunoglobulin is used as the starting material. This fraction is not particularly limited in so far as it originates from human plasma and contains an immunoglobulin fraction. Specific examples of such an immunoglobulin-containing fraction include Fraction II+III and Fraction II obtainable by ethanol fractionation of Cohn, and paste of immunoglobulin-containing fractions equivalent thereto. Other starting materials are Fractions I+II+III, and Fraction II+IIIw. The starting material may contain impurities, such as human blood-group antibodies, plasminogen, plasmin, kallikrein, prekallikrein activator, IgM, IgA, IgG polymers (hereinafter and hereinbefore “aggregates”), etc.
The preferred starting materials are Cohn Fraction II or Cohn Fraction II+III. When Cohn Fraction II+III paste is used, it is recommended that it first be subjected to a preliminary washing procedure to form Fraction II+IIIw, which is thereafter used in the process of this invention. “Fraction II+IIIw” is a disodium phosphate solution-washed Cohn Fraction II+III precipitate.
Fraction II+IIIw can be obtained by suspending Fraction II+III precipitate in cold water for injection in a ratio of about 1 kilogram of II+III paste per about 20 volumes of water. A sodium phosphate solution is added to the final concentration of approximately 0.003M sodium phosphate for solubilizing lipids, lipoproteins and albumin. Cold ethanol is added to bring the final alcohol concentration to about 20%. During the alcohol addition, temperature is gradually lowered to −5±1° C. and pH is maintained or adjusted to 7.2±0.1, for example by using acetate buffer or di
Bagdasarian Andranik
Canaveral Gorgonio
Mamidi Raja R.
Takechi Kazuo
Alpha Therapeutic Corporation
Brumback Brenda
Sughrue Mion Zinn Macpeak & Seas, PLLC
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