Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
  • A61L2/00—Disinfection or sterilisation of materials or objects, in general; Accessories therefor
  • A61L2/02—Disinfection or sterilisation of materials or objects, in general; Accessories therefor using physical processes
  • A61L2/04—Heat
• • C—CHEMISTRY; METALLURGY
  • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
  • C12N—MICROORGANISMS OR ENZYMES; COMPOSITIONS THEREOF; PROPAGATING, PRESERVING, OR MAINTAINING MICROORGANISMS; MUTATION OR GENETIC ENGINEERING; CULTURE MEDIA
  • C12N7/00—Viruses; Bacteriophages; Compositions thereof; Preparation or purification thereof
  • C12N7/04—Inactivation or attenuation; Producing viral sub-units
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
  • A61L2103/00—Materials or objects being the target of disinfection or sterilisation
  • A61L2103/05—Living organisms or biological materials

Definitions

• This invention relates to the field of sterilization of products derived from blood and other biological sources
• the invention involves heating biologically active products in the presence of trehalose for a time and under conditions sufficient to kill viruses, particularly parvovirus
• a wide variety of products with therapeutic utility are derived from biological sources such as plasma and cell lines Most of the plasma used for fractionation in the United States is obtained by plasmapheresis at collection centers distributed across the country The centers provide plasma to commercial fractionators in the United States and Europe About 9 million liters of plasma are collected per year from about 13 million donations The Red Cross adds approximately 800,000 liters to this number.
• Products from human plasma may be classified into several groups the albumin products, the immune globulins; the cold insoluble globulins, the coagulation products, and the protease inhibitors
• the albumin products also termed fraction V products, are used primarily to restore colloidal osmotic pressure in conditions of shock such as burn, or hemorrhagic shock where fluid loss is a principal problem
• the immune globulins are isolated from fraction II and contain a mixture of antibodies representative of the plasma pool source
• a number of hvperimmune globulins used for passive immunization are isolated from donor plasma with high levels of protective antibody
• the cold insoluble globulins include fibrinogen and von Willebrand's factor
• the coagulation products include the antihemophilic factor VI11 and factor IX complex used for replacement therapy in hemophilia A and B, respectively
• An activated form of factor IX complex called anti-inhibitor coagulant complex is prepared and used for treating patients with a factor VIII inhibitor
• the protease inhibitors include ⁇ l proteinase inhibitor, also known as ⁇ l anti-trypsin which is used to treat a congenital deficiency
• Antithrombin 111 is an inhibitor that is also congenitally deficient leading to thrombotic complications
• HSA human serum albumin
• the major blood-borne viruses of clinical concern include the hepatitis B and C viruses and the HIV and HTLV retroviruses With respect to blood derivatives, HTLVI and II and cytomegalovirus (CMB) appear to be cell- associated and thus do not present a risk in cell-free products
• the virus inactivation methods currently in use may also cause changes in the biological activity of the biological products obtained Immunogenicity of the products is especially of concern where sterilization treatment may induce protein unfolding and/or aggregation
• sterilization treatment may induce protein unfolding and/or aggregation
• factor VIII concentrates display evidence of FVIII activation, with higher one-stage than two- stage potencies, more rapid FXa generation, and increased lower molecular weight polypeptides
• Viral inactivation procedures may also induce changes in non-FVlll components and these may be partly responsible for the immunosuppressive activity of some of these concentrates Barrowcliffe ( 1993) I ' irological Safety Aspects of Plasma Derivatives Brown, ed Dev Biol Stand Basel, Karger, vol. 81, pp 125-135
• parvovirus Human parvovirus is a recently discovered agent that was given the code name B 19 Cossart et al (1975) Lancet 1.72-73 It is a very small (24 nm) single-stranded DNA virus with a very simple protein coat, but no lipid outer envelope It causes a transient viraemia of 1-2 weeks but can achieve extraordinarily high circulating virus titres of at least 10 " virus particles per ml
• parvovirus normally causes a relatively minor illness that is frequently not clinically apparent, producing a mild rubella-like rash known as fifth disease or erythema infectiosum, it can also cause more severe reactions Parvovirus infects bone marrow stem cells and this can cause a severe, life-threatening condition in patients with a preexisting, underlying anemia Aplastic crisis as a result of acute interruption of haemopoiesis may occur in patients with congenital haemolytic anaemias and immuno-deficiency states Parvovirus also causes hydrops fetalis in
• Heating in solution is commonly used for albumin products. This is otherwise known as pasteurization 17
• Viruses are inactivated by heating the liquid samples for at least 10 hours at 60°C in the presence of a small amount of stabilizer such as caprylate or tryptophanate This method is unsuitable for other products, however, as most proteins denature under these conditions Pasteurization has been shown to inactivate a wide spectrum of viruses including HIV, HBV, HCV, HAV, HSV, poliovirus CMV, mumps virus, measles virus and rubella virus Nowak et al (1993) I ' irological Safety Aspects of Plasma Derivatives, Brown, ed , Dev.
• stabilizer such as caprylate or tryptophanate
• Solvent/Detergent (SD) inactivation of viruses relies on the disruption of the membranes of viruses that have lipid envelopes The viruses are rendered non-infectious either by structural disruption or destruction of the cell receptor recognition site Although most human pathogenic viruses have a lipid envelope, parvovirus and HAV do not and are not inactivated by this method
• the SD method is in use in numerous countries Horowitz et al (1993) Vir ⁇ / ⁇ gicai Safety Aspects of Plasma Derivatives: Brown, ed Dev.
• Trehalose ( ⁇ -D-glucopyranosyl- ⁇ -D-glucopyranoside), is a naturally occurring, non-reducing disaccharide which was initially found to be associated with the prevention of desiccation damage in certain plants and animals which can dry out without damage and can revive when rehydrated Trehalose is available commercially in the dihydrate form.
• Trehalose has been shown to be useful in preventing denaturation of proteins, viruses and foodstuffs during desiccation See U.S Patent Nos 4,891,319; 5,149,653; 5,026,566; Blakeley et al (1990) Lancet 336:854-855; Roser (July 1991 ) Trends in Food Sci. and Tech. 166-169, Cola ⁇ o et al.
• Trehalose is found extensively in such diverse animal and plant species as bacteria, yeast, fungi, insects and invertebrates In many insects, it is the major blood sugar The only major source for man is dietary in foods such as mushrooms and yeast products Madsarovova-Nohejlova ( 1973) Gastroenterol 65 130-133
• Trehalose is described for use in a peritoneal dialysis system in U S Patent No 4,879,280 where it is mentioned as one of several disaccharides as a replacement for the prior art system which utilized glucose Trehalose is mentioned for use in the dialysis system as a disaccharide that will not be readily cleaved to glucose and thus avoid raising the blood glucose level
• Trehalose has also been described as suitable for use in parenteral formulations primarily because it can be sterilized by autoclaving without the browning associated with conventional parenteral formulations Japanese Patent No 6-70718
• Trehalose is a common component of the human diet and information is available on its metabolism Following oral ingestion, trehalose is not absorbed intact through the gastrointestinal tract, as only monosaccharides can pass throughout the intestinal epithelium Ravich and Bayless (1983) Clin. Gast 12 335-356 Trehalose is metabolized by the enzyme trehalase into two molecules of glucose Sacktor ( 1968) Proc. Natl. Acad. Sci. USA 60 1007- 1014 Trehalase is a normal constituent of most mammalian bodies, including humans, and has been identified in human serum, lymphocytes and the liver, but is principally located in the brush border of the intestinal tract and the renal proximal tubules Belfiore et al (1973) Clin. Chem.
• the invention relates to methods of sterilizing products, particularly therapeutic products, derived from biological sources and the compositions obtained thereby
• the methods include drying the product in the presence of an amount of trehalose sufficient to render heat stability to the product and exposing the dried sample to heating conditions at a temperature and for a duration sufficient to substantially inactivate viruses
• the heating conditions are sufficient to inactivate non-lipid encapsulated viruses
• the drying methods are any known in the art including both ambient drying conditions, including spray and vacuum drying, and lyophilization
• the heating conditions cover a wide range of temperatures and heating time combinations
• compositions obtained by the methods contain stable biological products and do not contain detectable infectious virus, particularly parvovirus
• biologically active products that can benefit from the sterilization methods provided herein include, but are not limited to, recombinantly produced proteins, native isolated proteins, antibodies, enzymes, cytokines and growth factors, as well as pharmaceutically active molecules such as analgesics, anesthetics, anti-emetics, antibiotics, chemotherapeutic agents, hormones vitamins and steroids
• any substance that is to be aseptically introduced into an individual include, but are not limited to, drugs, antibiotics, imaging agents diagnostic reagents
• the product to be administered is labile, such as cephalosporins, therapeutic antibodies and erythropoietin
• the invention provides stable, dried, sterile compositions that can be rehydrated just prior to use Trehalose is well suited for injectable, infusible etc agents in that it breaks down to two molecules of glucose upon exposure to trehalase in the bloodstream The glucose may cause a minor, transient increase in blood sugar levels but this is of little clinical concern
• the present invention encompasses methods of terminal sterilization of products that need to be administered aseptically to an individual
• the steps of the method include obtaining a dried sample containing the product and an amount of ⁇ -D-glucopyranosyl- ⁇ -D-glucopyranoside (trehalose) sufficient to render substantial heat stability to the product, and heating the dried sample at a temperature and for a duration sufficient to substantially inactivate viruses, preferably under heating conditions that inactivate non-lipid encapsulated viruses
• the dried sample may further contain suitable buffers, adjuvants, etc. Preferably in an amount that yields a suitable concentration upon rehydration
• the product can be derived from a variety of sources.
• the products are derived from any known biological source, including, but not limited to, blood, plasma, serum, placenta, milk, urine, cell cultures, and cell culture supernatant
• the product can be derived synthetically, either by chemical or enzymatic syntheses or by the use of recombinant DNA techniques Methods of preparation of these sources and methods of isolation of the products are well known in the art.
• products isolated or derived from blood, plasma and serum include, but are not limited to, albumin products, immune globulins, coagulation products, and protease inhibitors.
• Albumin products include, but are not limited to, HSA, cold insoluble globulins and fibrinogen.
• Immune globulins include, but are not limited to.
• antibodies against tetanus, pertussis, hepatitis B, Rho (D), varicella zoster, and rabies Coagulation products include, but are not limited to, antihemophilic factor VIII, factor IX complex, and activated factor IX complex
• Protease inhibitors include, but are not limited to, ⁇ -1 protease inhibitor, ⁇ -1 antitrypsin and antithrombin III
• albumin can be obtained from placental sources
• the products include, but are not limited to, colony stimulating factors, monoclonal antibodies and derivatives thereof, and growth factors Typical growth factors include, but are not limited to, both naturally derived and recombinant erythropoietin, cytokines and interleukins
• the products include, but are not limited to, analgesics, anesthetics, chemotherapeutic agents, hormones and vaccines.
• Analgesics include, but are not limited to, morphine, benzocaine, pethidine, and Demerol
• anesthetics include, but are not limited to, bupivicaine, atracurium and vecuronium
• Chemotherapeutic agents include, but are not limited to, radioisotopes, vinca alkaloids such as the vinblastine, vincristine and vindesine sulfates, adriamycin, bleomycin sulfate, Carboplatin, cisplatin, cyclophosphamide, Cytarabine, dacarbazine, Dactinomycin, Duanorubicin hydrochloride, Doxorubicin hydrochloride, Etoposide, fluorouracil, mechlororethamine
• Suitable hormones include, but are not limited to estrogen, testosterone, progesterone and synthetic analogs thereof
• Typical vaccines include, both single and multiple antigen subunit vaccines as well as killed bacterial and viral preparations and cancer antigens
• Typical antibiotics include, but are not limited to, cephalosporins and aminoglycosides
• the method includes a first step of obtaining a dried sample
• a variety of methods may be utilized to dry the sample These include, but are not limited to, air drying, vacuum drying, spray drying and freeze drying These methods are exemplified in detail in the examples presented herein and are well known in the art See, e g U S Patent Nos 4,891,319, 5,026,566, and 5, 149,653
• the samples are typically prepared in solution or suspension and include the product, a sufficient amount of trehalose to render heat stability to the product, and any other typical additive such as suitable buffers, adjuvants, etc
• trehalose is present in an amount of 1-50% by weight of the solution
• the trehalose can be more dilute or concentrated If less dilute, drying times may be prohibitive, and, if more concentrated, the solution may become viscous
• concentration of product and trehalose is such that after drying less than about 30% loss of activity of the product occurs More preferably, there is less than 15% loss of activity and most preferably, there is less than 10% loss
• the optimal conditions are determined by spiking a test sample with either the virus to be inactivated or a virus having similar physical characteristics.
• a loss of four log,,, titre of the spiked virus is considered to be "inactivation" as a 4 log,,, drop in titre is loss is the regulatory authority requirement for viral inactivation/removal procedure
• the method results in substantial heat stability of the product Preferably, the method results in less than about a 30% loss in activity of the product More preferably, the method results in less than about 15% loss in activity of the product Most preferably, the method results in less than about 10% loss in activity of the product.
• the method provides dried samples of high stability and capable of being stored for long periods of time This storage stability is related to the residual moisture of the sterilized product
• the method produces a dried sample having a residual moisture content of less than about 4% More preferably, the residual moisture content is less than about 2% Most preferably, the residual moisture content is about 0 8-1 0%
• Residual moisture can be measured by a variety of methods, including, but not limited to, differential thermal analysis, thermogravimetric methods or Karl Fisher coulometric titration
• the range of heating temperature and times varies widely, the optimum time for a particular sample can be determined empirically given the knowledge in the field and the examples provided herein
• the results presented herein indicate that heating at about 80°C for about 72 hours is effective, as is heating at 90°C for about 20 hours Longer time periods and/or higher temperatures may be utilized with potential concomitant loss in product activity
• the method results in a four log, 0 fold reduction in infectivity of the contaminating viruses.
• lipid encapsulated viruses are less resistant to heat treatment than non-lipid encapsulated viruses, a determination ofthe loss of infectiousness of a non-lipid encapsulated virus indicates that all lipid encapsulated viruses have also been inactivated
• the non-lipid encapsulated viruses include, but are not limited to, hepatitis A virus and parvoviruses
• the non-lipid encapsulated virus is parvovirus.
• compositions obtained by the methods of the claimed invention are free of detectable infective viruses and are extremely storage stable
• reduced denaturation or chemical degradation of therapeutic products during processing results in a decrease in the incidence of immune reactions to recipients of the products
• compositions are preferably in single dosage form, especially for drugs such as analgesics and chemotherapeutics.
• Single dosage forms can be produced by aliquoting the initial solution or suspension into suitable containers and processing the containers separately Preferably, such aliquoting and processing is automated Alternatively, the material can be processed in batches of more than one dose and the dried product can be divided into single doses The invention thus encompasses single dose forms of the claimed composition
• the shelf temperature was initially set at 30°C while the vacuum was reduced in a stepwise fashion to 30 mTorr, when the shelf temperature was increased to 60°C and the drying carried out for a further 12-16 hrs
• the samples were frozen by reducing the shelf temperature to -40°C at 5°C per minute and the vials were allowed to freeze completely for 1 hour before the vacuum was reduced 10 mTorr and the samples dried at -40°C for 40 hours
• the shelf temperature was then raised to +20°C at 0 05°C per minute and samples dried at +20°C for 3 hours and finally the shelf temperature was raised to +40°C at 0 05°C per minute and samples dried at +40°C for a further 2 hours
• Vials were stoppered under vacuum and samples were kept at 4°C as dried controls
• vials were treated at 80°C for 72 hours or 90°C for 20 hours in an Heraeus drying oven Log , 0 reduction in parvovirus activity and % reduction in alkaline pho
• Parvovirus was assayed by titration on cell culture and the endpoint was determined by agglutination of porcine red blood cells. Briefly, dried samples were reconstituted in their original volume using sterile distilled water and a tenfold dilution series prepared in Eagles Minimum Essential Maintenance culture media (EMEM) A suspension of A72 cells in EMEM containing 5% fetal bovine serum was prepared by trypsinisation of a confluent flask of cells and a 1 ml of cell suspension containing 2-5x 10 cells/ml was aliquoted into the wells of a 24 well cell culture plate 100 ⁇ l of each dilution of viral sample was inoculated into four replicate wells ofthe cell culture plate and the plates incubated for 14 days at 37°C in an atmosphere of 5% CO 2
• EMEM Eagles Minimum Essential Maintenance culture media
• Alkaline phosphatase was assayed colorometrically, using the commercial reagent, Sigma fast alkaline phosphatase substrate assay Briefly, a doubling dilution series was prepared for the samples and a standard alkaline phosphatase preparation ( lmg / ml) and 100 Tl of substrate was added to 100 Tl of sample in an EIA plate and incubated in the dark for 30 minutes Color development was read at 405 nm using a titertek multiscan interfaced with a delta soft plate reader package and the activity of the samples was calculated from absorbance values corresponding to the linear section of the standard curve Dried controls were assigned 100% activity and % reduction in activity of the treated samples were calculated from these values.
• Example 2 Terminal sterilization to eliminate parvovirus infectivity without loss of biological activity by vacuum drying in trehalose, effect of temperature and time
• Table 2 depicts the log !0 reduction in parvovirus titre and % reduction in alkaline phosphatase activity following terminal sterilization at 80°C for 72 hours or 90°C for 144 hours
• * stands for log
• 0 TCID 50 / ml parvovirus in dried control 6
• > stands for below the detection limit of the assay
• Example 2 the same formulations as in Example 1 were spiked with three different virus preparations: poliovirus; parvovirus (non-enveloped RNA and DNA containing viruses respectively), and measles virus (enveloped RNA virus)
• poliovirus parvovirus
• parvovirus non-enveloped RNA and DNA containing viruses respectively
• measles virus enveloped RNA virus
• Logio reduction in virus titre and % reduction in alkaline phosphatase activity were evaluated as described previously or below Poliovirus was assayed using a cell cytopathic assay Briefly, dried samples were reconstituted in their original volume using sterile distilled water and a tenfold dilution series prepared in EMEM and 100 ⁇ l dilutions were inoculated into five replicate wells of a 96 well cell culture plate containing a confluent monolayer of Vero cells The plates were incubated for 7 days and virus induced cytopathic effect scored by inspection of the wells using light
• Measles virus infectivity was determined using a plaque assay Briefly, dried samples were reconstituted in their original volume using sterile distilled water and a tenfold dilution series prepared in EMEM 200 ⁇ l of each dilution was inoculated into duplicate wells of a 6 well plate containing a confluent monolayer of Vero cells After virus adsorption to the cells for 1 hour at 37°C, 2 ml of overlay medium (EMEM containing 1% carboxymethyl cellulose and 5% foetal bovine serum) was added to each well The plates were then incubated for /GB97/01317
• Example 4 Terminal sterilization to eliminate parvovirus from blood product without loss of biological activity by drying in trehalose
• Fibrinogen (Fraction 1, Type 1 -S, Sigma Chemical company) was dissolved in 10% and 25% solutions of either trehalose or sucrose containing 10% sodium citrate and 15% sodium chloride and the solutions centrifuged to remove any insoluble material and the protein concentrations adjusted to a final fibrinogen concentration of 5 mg/ml.
• the stock fibrinogen solutions were was spiked with 10 6 5 TCID 50 / ml canine parvovirus and 12 ml aliquots of the fibrinogen solution were dispensed into 5 ml Wheaton pharmaceutical glass vials and the samples vacuum dried in an FTS drier or freeze dried in a Labconco freeze-drier.
• the drier shelves were pre-cooled to 10°C and vacuum reduced to 30,000 mTorr.
• the shelf temperature was then raised to 40 °C and the vacuum reduced to 30,000 ,Torr for 2 minutes, 20,000 mTorr for 2 minutes and 10,000 mTorr for 20 minutes
• the vacuum was then raised to 30,000 mTorr for 5 minutes and then reduced to 30 mTorr and the samples dried overnight at a shelf temperature of 60°C
• the samples were frozen at 5 °C /min to -40 °C, held at -40 °C for 16 hours and then the shelf temperature was raised to -35 °C and the samples dried at a vacuum of 10 mTorr for 80 hours
• the shelf temperature was raised to 25 °C and the samples dried at a vacuum of 10 mTorr for a further 5 hours All the vials were sealed under vacuum and samples to be terminally sterilized were heat sterilized by heating in a Heraeus oven at 90°C for 20 or 48 hours
• the clotting assay for fibrinogen was a modification of the National Institute of Biological Standards thrombin clotting assay Briefly, fibrinogen samples and standards were clotted by addition of thrombin to the fibrinogen solution and the protein concentration in the clot measured by solubilisation of the clot in 7M urea and quantitating the absorbance at 280 nm

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