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WO2008151193A1 - Compositions et procédés de traitement de la colonne vertébrale - Google Patents

Compositions et procédés de traitement de la colonne vertébrale Download PDF

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Publication number
WO2008151193A1
WO2008151193A1 PCT/US2008/065666 US2008065666W WO2008151193A1 WO 2008151193 A1 WO2008151193 A1 WO 2008151193A1 US 2008065666 W US2008065666 W US 2008065666W WO 2008151193 A1 WO2008151193 A1 WO 2008151193A1
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WO
WIPO (PCT)
Prior art keywords
pdgf
composition
vertebral body
vertebral
biocompatible matrix
Prior art date
Application number
PCT/US2008/065666
Other languages
English (en)
Inventor
Charles E. Hart
Samuel E. Lynch
Conan S. Young
Dan Perrien
Original Assignee
Biomimetic Therapeutics, Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Biomimetic Therapeutics, Inc. filed Critical Biomimetic Therapeutics, Inc.
Priority to CA2689986A priority Critical patent/CA2689986C/fr
Priority to CN200880101796A priority patent/CN101820895A/zh
Priority to AU2008259785A priority patent/AU2008259785B2/en
Publication of WO2008151193A1 publication Critical patent/WO2008151193A1/fr
Priority to US12/631,731 priority patent/US9161967B2/en
Priority to US14/853,901 priority patent/US11058801B2/en
Priority to US17/373,330 priority patent/US20220105246A1/en

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Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K38/00—Medicinal preparations containing peptides
    • A61K38/16—Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof
    • A61K38/17—Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof from animals; from humans
    • A61K38/18—Growth factors; Growth regulators
    • A61K38/1858—Platelet-derived growth factor [PDGF]
    • 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
    • A61L27/00—Materials for grafts or prostheses or for coating grafts or prostheses
    • A61L27/14—Macromolecular materials
    • A61L27/22—Polypeptides or derivatives thereof, e.g. degradation products
    • A61L27/227—Other specific proteins or polypeptides not covered by A61L27/222, A61L27/225 or A61L27/24
    • 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
    • A61L27/00—Materials for grafts or prostheses or for coating grafts or prostheses
    • A61L27/50—Materials characterised by their function or physical properties, e.g. injectable or lubricating compositions, shape-memory materials, surface modified materials
    • A61L27/54—Biologically active materials, e.g. therapeutic substances
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
    • A61P19/00—Drugs for skeletal disorders
    • A61P19/08—Drugs for skeletal disorders for bone diseases, e.g. rachitism, Paget's disease
    • 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
    • A61L2300/00—Biologically active materials used in bandages, wound dressings, absorbent pads or medical devices
    • A61L2300/40—Biologically active materials used in bandages, wound dressings, absorbent pads or medical devices characterised by a specific therapeutic activity or mode of action
    • A61L2300/412—Tissue-regenerating or healing or proliferative agents
    • A61L2300/414—Growth factors
    • 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
    • A61L2300/00—Biologically active materials used in bandages, wound dressings, absorbent pads or medical devices
    • A61L2300/40—Biologically active materials used in bandages, wound dressings, absorbent pads or medical devices characterised by a specific therapeutic activity or mode of action
    • A61L2300/44—Radioisotopes, radionuclides
    • 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
    • A61L2430/00—Materials or treatment for tissue regeneration
    • A61L2430/38—Materials or treatment for tissue regeneration for reconstruction of the spine, vertebrae or intervertebral discs

Definitions

  • the present invention relates to compositions and methods useful for treating structures of the vertebral column, including vertebral bodies.
  • VCFs Vertebral compression fractures
  • VCFs occur when there is a break in one or both of the vertebral body end plates, usually due to trauma, causing failure of the anterior column and weakening the vertebrae from supporting the body during activities of daily living.
  • Vertebral compression fractures caused by osteoporosis can cause debilitating back pain, spinal deformity, and height loss. Both symptomatic and asymptomatic vertebral fractures are associated with increased morbidity and mortality. With the number of aged people at risk for osteoporosis is expected to increase dramatically in the coming decades, accurate identification of VCFs and treatment intervention is necessary to reduce the enormous potential impact of this disease on patients and health care systems.
  • VCFs caused by osteoporosis have been treated with bed rest, narcotic analgesics, braces, and physical therapy.
  • Bed rest leads to accelerated bone loss and physical deconditioning, further aggravating the patient as well as contributing to the problem of osteoporosis.
  • narcotics can worsen the mood and mentation problem that may already be prevalent in the elderly.
  • brace wear is not well-tolerated by the elderly.
  • Vertebroplasty does not attempt to restore vertebral height and/or sagittal alignment.
  • vertebral filling is performed under less control with less viscous cement and, as a consequence, filler leaks are common.
  • Kyphoplasty is a minimally invasive surgical procedure with the goal of safety, improving vertebral height and stabilizing VCF. Guided by x-ray images, an inflatable bone tamp is inflated in the fractured vertebral body. This compacts the inner cancellous bone as it pushes the fractured cortices back toward their normal position. Fixation can then be done by filling the void with a biomaterial under volume control with a more viscous cement. Although kyphoplasty is considered a safe and effective treatment of vertebral compression fractures, biomechanical studies demonstrate that cement augmentation places additional stress on adjacent levels.
  • compositions and methods useful for treating structures of the vertebral column including vertebral bodies.
  • compositions are provided for promoting bone formation in a vertebral body.
  • compositions and methods are provided for preventing or decreasing the likelihood of vertebral compression fractures.
  • methods and compositions are provided for preventing or decreasing the likelihood of secondary vertebral compression fractures associated with vertebroplasty and/or kyphoplasty.
  • the present compositions and methods can be useful in treating vertebral bodies of compromised patients, such as those with osteoporosis, diabetes, or other diseases or conditions.
  • a composition for promoting bone formation in a vertebral body comprises a solution comprising platelet derived growth factor (PDGF) and biocompatible matrix, wherein the solution is disposed or incorporated in the biocompatible matrix.
  • PDGF platelet derived growth factor
  • the PDGF is absorbed by the biocompatible matrix.
  • the PDGF is adsorbed onto one or more surfaces of the biocompatible matrix.
  • the PDGF is absorbed by the biocompatible matrix and adsorbed onto one or more surfaces of the biocompatible matrix.
  • PDGF is present in the solution in a concentration ranging from about 0.01 mg/ml to about 10 mg/ml, from about 0.05 mg/ml to about 5 mg/ml, from about 0.1 mg/ml to about 1.0 mg/ml, or from about 0.2 mg/ml to about 0.4 mg/ml.
  • concentration of PDGF within the solution may be within any of the concentration ranges stated above.
  • PDGF comprises PDGF homodimers and heterodimers, including PDGF-AA, PDGF-BB, PDGF-AB, PDGF-CC, PDGF-DD, and mixtures and derivatives thereof.
  • PDGF comprises PDGF-BB.
  • PDGF comprises a recombinant human (rh) PDGF such as recombinant human PDGF-BB (rhPDGF-BB).
  • PDGF comprises PDGF fragments.
  • rhPDGF-B comprises the following fragments: amino acid sequences 1-31, 1- 32, 33-108, 33-109, and/or 1-108 of the entire B chain.
  • the complete amino acid sequence (1- 109) of the B chain of PDGF is provided in Figure 15 of U.S. Patent No. 5,516,896.
  • the rhPDGF compositions of the present invention may comprise a combination of intact rhPDGF-B (1-109) and fragments thereof.
  • Other fragments of PDGF may be employed such as those disclosed in U.S. Patent No. 5,516,896.
  • rhPDGF-BB comprises at least 65% of intact rhPDGF-B (1-109).
  • a biocompatible matrix comprises a bone substituting agent (also called a scaffolding material herein) and optionally a biocompatible binder.
  • Bone substituting agents comprise calcium phosphate including amorphous calcium phosphate, monocalcium phosphate monohydrate (MCPM), monocalcium phosphate anhydrous (MCPA), dicalcium phosphate dihydrate (DCPD), dicalcium phosphate anhydrous (DCPA), octacalcium phosphate (OCP), ⁇ -tricalcium phosphate, ⁇ -TCP, hydroxyapatite (OHAp), poorly crystalline hydroxapatite, tetracalcium phosphate (TTCP), heptacalcium decaphosphate, calcium metaphosphate, calcium pyrophosphate dihydrate, calcium pyrophosphate, carbonated calcium phosphate, hydroxyapatite, or derivatives or mixtures thereof.
  • bone substituting agents comprise calcium sulfate or demineralized bone such as dried cortical or cancellous bone.
  • the present invention provides a composition for promoting bone formation in a vertebral body comprising a PDGF solution disposed in a biocompatible matrix, wherein the biocompatible matrix comprises a bone scaffolding material and a biocompatible binder.
  • the PDGF solution may have a concentration of PDGF as described above.
  • a bone scaffolding material in some embodiments, comprises calcium phosphate.
  • calcium phosphate comprises ⁇ -TCP.
  • biocompatible matrices may include calcium phosphate particles with or without biocompatible binders or bone allograft such as demineralized freeze dried bone allograft (DFDBA), mineralized freeze dried bone allograft (FDBA), or particulate demineralized bone matrix (DBM).
  • DMDBA demineralized freeze dried bone allograft
  • FDBA mineralized freeze dried bone allograft
  • DBM particulate demineralized bone matrix
  • biocompatible matrices may include bone allograft such as DFDBA, DBM, or other bone allograft materials including cortical bone shapes, such as blocks, wedges, cylinders, or particles, or cancellous bone particles of various shapes and sizes.
  • bone allograft such as DFDBA, DBM, or other bone allograft materials
  • cortical bone shapes such as blocks, wedges, cylinders, or particles, or cancellous bone particles of various shapes and sizes.
  • a biocompatible binder comprises proteins, polysaccharides, nucleic acids, carbohydrates, synthetic polymers, or mixtures thereof.
  • a biocompatible binder comprises collagen.
  • a biocompatible binder comprises hyaluronic acid.
  • a composition for preventing or decreasing the likelihood of vertebral compression fractures comprises a solution comprising PDGF and a biocompatible matrix wherein the solution is disposed in the biocompatible matrix.
  • a composition for preventing or decreasing the likelihood of vertebral compression fractures comprises a PDGF solution disposed in a biocompatible matrix, wherein the biocompatible matrix comprises a bone scaffolding material and a biocompatible binder.
  • a PDGF solution may have a concentration of PDGF as described above.
  • a bone scaffolding material in some embodiments, comprises calcium phosphate.
  • calcium phosphate comprises ⁇ -tricalcium phosphate.
  • a biocompatible binder according to some embodiments of the present invention, comprises proteins, polysaccharides, nucleic acids, carbohydrates, synthetic polymers, or mixtures thereof.
  • a biocompatible binder comprises collagen.
  • a biocompatible binder comprises collagen, such as bovine collagen.
  • compositions for promoting bone formation in vertebral bodies and compositions for preventing or reducing the likelihood of vertebral compression fractures further comprise at least one contrast agent.
  • Contrast agents are substances operable to at least partially provide differentiation of two or more bodily tissues when imaged.
  • Contrast agents according to some embodiments, comprise cationic contrast agents, anionic contrast agents, nonionic contrast agents, or mixtures thereof.
  • contrast agents comprise radiopaque contrast agents.
  • Radiopaque contrast agents comprise iodo-compounds including (S)-N,N'-bis[2-hydroxy-l-(hydroxymethyl)-ethyl]-2,4,6-triiodo-5-lactamidoisophthalamide (Iopamidol) and derivatives thereof.
  • the present invention provides a kit comprising a biocompatible matrix in a first package and a solution comprising PDGF in a second package.
  • the biocompatible matrix comprises a scaffolding material, a scaffolding material and a biocompatible binder, and/or bone allograft such as DFDBA or particulate DBM.
  • the scaffolding material comprises a calcium phosphate, such as ⁇ -TCP.
  • the solution comprises a predetermined concentration of PDGF. The concentration of the PDGF can be predetermined according to the surgical procedure being performed, such as promoting or accelerating bone growth in a vertebral body or preventing or decreasing the likelihood of secondary vertebral compression fractures.
  • the biocompatible matrix can be present in the kit in a predetermined amount.
  • the amount of biocompatible matrix provided by a kit can be dependent on the surgical procedure being performed.
  • the second package containing the PDGF solution comprises a syringe.
  • a syringe can facilitate disposition of the PDGF solution in the biocompatible matrix.
  • the present invention also provides methods of producing compositions for promoting bone formation in vertebral bodies and preventing or decreasing the likelihood of compression fractures of vertebral bodies, including secondary vertebral compression fractures.
  • a method for producing such compositions comprises providing a solution comprising PDGF, providing a biocompatible matrix, and disposing the solution in the biocompatible matrix.
  • a method of producing compositions for promoting bone formation in a vertebral body and preventing or decreasing the likelihood of compression fracture in a vertebral body further comprises providing a contrast agent and disposing the contrast agent in the biocompatible matrix.
  • the present invention provides methods for promoting or accelerating bone formation in a vertebral body comprising providing a composition comprising a PDGF solution disposed in a biocompatible matrix and applying an effective amount of the composition to at least one vertebral body. Applying the composition to at least one vertebral body, in some embodiments, comprises injecting the composition into the at least one vertebral body.
  • the present invention provides methods comprising preventing or decreasing the likelihood of vertebral compression fractures, including secondary vertebral compression fractures.
  • Preventing or decreasing the likelihood of vertebral compression fractures comprises providing a composition comprising a PDGF solution disposed in a biocompatible matrix and applying an effective amount of the composition to at least one vertebral body.
  • applying the composition to at least one vertebral body comprises injecting the composition into the at least one vertebral body.
  • the composition is applied to a second vertebral body, in some instances an adjacent vertebral body, subsequent to a vertebroplasty or kyphoplasty of a first vertebral body.
  • a composition comprising a PDGF solution disposed in a biocompatible matrix is applied to at least one high risk vertebral body.
  • High risk vertebral bodies refer to vertebral bodies of vertebrae T5 through T 12 as well as Ll through L4, which are at the greatest risk of undergoing secondary vertebral compression fracture.
  • the biocompatible matrix comprises a bone scaffolding material.
  • the biocompatible matrix comprises a bone scaffolding material and a biocompatible binder.
  • methods for promoting bone formation in vertebral bodies and preventing or decreasing the likelihood of compression fractures of vertebral bodies further comprise providing at least one pharmaceutical composition in addition to the composition comprising a PDGF solution disposed in a biocompatible matrix and administering the at least one pharmaceutical composition locally and/or systemically.
  • the at least one pharmaceutical composition in some embodiments, comprises vitamins, calcium supplements, or any osteoclast inhibitor known to one of skill in the art, including bisphosphonates.
  • the at least one pharmaceutical composition is administered locally.
  • the at least one pharmaceutical composition can be incorporated into the biocompatible matrix or otherwise disposed in and around a vertebral body.
  • the at least one pharmaceutical composition is administered systemically to a patient.
  • the at least one pharmaceutical composition is administered orally to a patient.
  • the at least one pharmaceutical composition is administered intravenously to a patient. Accordingly, it is an object of the present invention to provide a composition comprising
  • PDGF useful in promoting bone formation in vertebral bodies.
  • Another object of the present invention is to provide methods for promoting bone formation in vertebral bodies using compositions comprising PDGF.
  • a further object of the present invention is to provide methods of preventing or decreasing the likelihood of vertebral compression fractures, including secondary vertebral compression fractures, using compositions comprising PDGF.
  • Figure 1 illustrates a syringe and related apparatus penetrating tissue overlaying a vertebral body to deliver a composition of the present invention to the vertebral body according to an embodiment of the present invention.
  • Figure 2 is a radiograph illustrating injection of a composition into a vertebral body according to an embodiment of the present invention.
  • Figure 3 illustrates vertebrae receiving compositions of the present invention according to one embodiment of the present invention.
  • Figure 4 illustrates percent change in volumetric bone mineral density for vertebral bodies receiving a composition comprising 1.0 mg/ml of rhPDGF-BB disposed in a ⁇ -TCP/collagen matrix in comparison with vertebral bodies receiving a composition comprising 20 mM sodium acetate buffer disposed in a ⁇ -TCP/collagen matrix according to one embodiment of the present invention.
  • Figure 5 illustrates percent change in volumetric bone mineral density for vertebral bodies receiving a composition comprising 1.0 mg/ml of rhPDGF-BB disposed in a ⁇ -TCP/collagen matrix in comparison with vertebral bodies receiving a composition comprising 20 mM sodium acetate buffer disposed in a ⁇ -TCP/collagen matrix according to one embodiment of the present invention.
  • the present invention provides compositions and methods useful for treating structures of the vertebral column, including vertebral bodies. According to embodiments described herein, the present invention provides compositions for promoting bone formation in a vertebral body and compositions for preventing or decreasing the likelihood of vertebral compression fractures, including secondary vertebral compression fractures.
  • the compositions comprise a solution comprising PDGF and a biocompatible matrix, wherein the solution is disposed in the biocompatible matrix.
  • the compositions comprise a PDGF solution disposed in a biocompatible matrix, wherein the biocompatible matrix comprises a bone scaffolding material and a biocompatible binder.
  • biocompatible matrices include calcium phosphate particles with or without biocompatible binders or bone allograft such as DFDBA or particulate DBM.
  • biocompatible matrices may include DFDBA or DBM.
  • compositions of the present invention comprise a solution comprising PDGF.
  • PDGF plays an important role in regulating cell growth and migration.
  • PDGF as with other growth factors, binds with the extracellular domains of receptor tyrosine kinases.
  • the binding of PDGF to these transmembrane proteins activate the kinase activity of their catalytic domains located on the cytosolic side of the membrane.
  • the kinases induce a variety of cellular processes that include cell growth and extracellular matrix production.
  • a composition provided by the present invention comprises a solution comprising PDGF and a biocompatible matrix, wherein the solution is disposed or incorporated in the biocompatible matrix.
  • PDGF is present in the solution in a concentration ranging from about 0.01 mg/ml to about 10 mg/ml, from about 0.05 mg/ml to about 5 mg/ml, or from about 0.1 mg/ml to about 1.0 mg/ml.
  • PDGF may be present in the solution at any concentration within these stated ranges including the upper limit and lower limit of each range.
  • PDGF is present in the solution at any one of the following concentrations: about 0.05 mg/ml; about 0.1 mg/ml; about 0.15 mg/ml; about 0.2 mg/ml; about 0.25 mg/ml; about 0.3 mg/ml; about 0.35 mg/ml; about 0.4 mg/ml; about 0.45 mg/ml; about 0.5 mg/ml, about 0.55 mg/ml, about 0.6 mg/ml, about 0.65 mg/ml, about 0.7 mg/ml; about 0.75 mg/ml; about 0.8 mg/ml; about 0.85 mg/ml; about 0.9 mg/ml; about 0.95 mg/ml; or about 1.0 mg/ml.
  • PDGF is present in the solution in a concentration ranging from about 0.2 mg/ml to about 2 mg/ml, from about 0.3 mg/ml to about 3 mg/ml, from about 0.4 mg/ml to about 4 mg/ml, or from about 0.5 mg/ml to about 5 mg/ml. It is to be understood that these concentrations are simply examples of particular embodiments, and that the concentration of PDGF may be within any of the concentration ranges stated above including the upper limit and the lower limit of each range. Various amounts of PDGF may be used in the compositions of the present invention.
  • Amounts of PDGF that could be used include amounts in the following ranges: about 1 ⁇ g to about 50 mg, about 10 ⁇ g to about 25 mg, about 100 ⁇ g to about 10 mg, and about 250 ⁇ g to about 5 mg.
  • the concentration of PDGF or other growth factors in embodiments of the present invention can be determined by using an enzyme-linked immunoassay as described in U.S. Patent Nos. 6,221,625, 5,747,273, and 5,290,708, or any other assay known in the art for determining PDGF concentration.
  • the molar concentration of PDGF is determined based on the molecular weight (MW) of PDGF dimer (e.g., PDGF-BB; MW about 25 kDa).
  • PDGF comprises PDGF homodimers and heterodimers, including PDGF-AA, PDGF-BB, PDGF-AB, PDGF-CC, PDGF-DD, and mixtures and derivatives thereof.
  • PDGF comprises PDGF-BB.
  • PDGF comprises a recombinant human PDGF, such as rhPDGF-BB.
  • PDGF comprises mixtures of the various homodimers and/or heterodimers.
  • Embodiments of the present invention contemplate any combination of PDGF-AA, PDGF-BB, PDGF-AB, PDGF-CC, and/or PDGF-DD.
  • PDGF in some embodiments, can be obtained from natural sources.
  • PDGF can be produced by recombinant DNA techniques.
  • PDGF or fragments thereof may be produced using peptide synthesis techniques known to one of ordinary skill in the art, such as solid phase peptide synthesis.
  • PDGF can be derived from biological fluids.
  • Biological fluids according to some embodiments, can comprise any treated or untreated fluid associated with living organisms including blood
  • Biological fluids in another embodiment, can also comprise blood components including platelet concentrate (PC), apheresed platelets, platelet-rich plasma (PRP), plasma, serum, fresh frozen plasma (FFP), and buffy coat (BC).
  • Biological fluids in a further embodiment, can comprise platelets separated from plasma and resuspended in a physiological fluid.
  • a DNA sequence encoding a single monomer e.g., PDGF B-chain or A-chain
  • a DNA sequence encoding a single monomer can be inserted into cultured prokaryotic or eukaryotic cells for expression to subsequently produce the homodimer (e.g. PDGF-BB or PDGF-AA).
  • a PDGF heterodimer can be generated by inserting DNA sequences encoding for both monomeric units of the heterodimer into cultured prokaryotic or eukaryotic cells and allowing the translated monomeric units to be processed by the cells to produce the heterodimer (e.g. PDGF-AB).
  • GMP recombinant PDGF-BB can be obtained commercially from Novartis Corporation (Emeryville, CA). Research grade rhPDGF-BB can be obtained from multiple sources including R&D Systems, Inc. (Minneapolis, MN), BD Biosciences (San Jose, CA), and Chemicon, International (Temecula, CA). In some embodiments, monomeric units can be produced in prokaryotic cells in a denatured form, wherein the denatured form is subsequently refolded into an active molecule.
  • PDGF comprises PDGF fragments.
  • rhPDGF-B comprises the following fragments: amino acid sequences 1-31, 1-32, 33-108, 33-109, and/or 1-108 of the entire B chain.
  • the complete amino acid sequence (1-109) of the B chain of PDGF is provided in Figure 15 of U.S. Patent No. 5,516,896.
  • the rhPDGF compositions of the present invention may comprise a combination of intact rhPDGF-B (1-109) and fragments thereof.
  • Other fragments of PDGF may be employed such as those disclosed in U.S. Patent No. 5,516,896.
  • the rhPDGF-BB comprises at least 60% of intact rhPDGF-B (1-109). In another embodiment, the rhPDGF-BB comprises at least 65%, 75%, 80%, 85%, 90%, 95%, or 99% of intact rhPDGF-B (1- 109).
  • PDGF can be purified.
  • Purified PDGF as used herein, comprises compositions having greater than about 95% by weight PDGF prior to incorporation in solutions of the present invention.
  • the solution may be any pharmaceutically acceptable solution.
  • the PDGF can be substantially purified.
  • Substantially purified PDGF as used herein, comprises compositions having about 5% to about 95% by weight PDGF prior to incorporation into solutions of the present invention.
  • substantially purified PDGF comprises compositions having about 65% to about 95% by weight PDGF prior to incorporation into solutions of the present invention.
  • substantially purified PDGF comprises compositions having about 70% to about 95%, about 75% to about 95%, about 80% to about 95%, about 85% to about 95%, or about 90% to about 95%, by weight PDGF, prior to incorporation into solutions of the present invention.
  • Purified PDGF and substantially purified PDGF may be incorporated into scaffolds and binders.
  • PDGF can be partially purified.
  • Partially purified PDGF comprises compositions having PDGF in the context of platelet rich plasma (PRP), fresh frozen plasma (FFP), or any other blood product that requires collection and separation to produce PDGF.
  • PRP platelet rich plasma
  • FFP fresh frozen plasma
  • Embodiments of the present invention contemplate that any of the PDGF isoforms provided herein, including homodimers and heterodimers, can be purified or partially purified.
  • Compositions of the present invention containing PDGF mixtures may contain PDGF isoforms or PDGF fragments in partially purified proportions.
  • Partially purified and purified PDGF in some embodiments, can be prepared as described in U.S. Patent Application Serial No.
  • solutions comprising PDGF are formed by solubilizing PDGF in one or more buffers.
  • Buffers suitable for use in PDGF solutions of the present invention can comprise, but are not limited to, carbonates, phosphates (e.g. phosphate buffered saline), histidine, acetates (e.g. sodium acetate), acidic buffers such as acetic acid and HCl, and organic buffers such as lysine, Tris buffers (e.g.
  • Buffers can be selected based on biocompatibility with PDGF and the buffer's ability to impede undesirable protein modification. Buffers can additionally be selected based on compatibility with host tissues. In one embodiment, sodium acetate buffer is used.
  • the buffers may be employed at different molarities, for example, about O.lmM to about 100 mM, about 1 mM to about 50 mM, about 5 mM to about 40 mM, about 10 mM to about 30 niM, or about 15 rnM to about 25 mM, or any molarity within these ranges.
  • an acetate buffer is employed at a molarity of about 20 mM.
  • solutions comprising PDGF are formed by solubilizing lyophilized PDGF in water, wherein prior to solubilization the PDGF is lyophilized from an appropriate buffer.
  • Solutions comprising PDGF can have a pH ranging from about 3.0 to about 8.0.
  • a solution comprising PDGF has a pH ranging from about 5.0 to about 8.0, from about 5.5 to about 7.0, or from about 5.5 to about 6.5, or any value within these ranges.
  • the pH of solutions comprising PDGF in some embodiments, can be compatible with the prolonged stability and efficacy of PDGF or any other desired biologically active agent.
  • PDGF is more stable in an acidic environment. Therefore, in accordance with one embodiment the present invention comprises an acidic storage formulation of a PDGF solution.
  • the PDGF solution preferably has a pH from about 3.0 to about 7.0 or from about 4.0 to about 6.5.
  • the biological activity of PDGF can be optimized in a solution having a neutral pH range. Therefore, in a further embodiment, the present invention comprises a neutral pH formulation of a PDGF solution.
  • the PDGF solution preferably has a pH from about 5.0 to about 8.0, from about 5.5 to about 7.0, or from about 5.5 to about 6.5.
  • an acidic PDGF solution is reformulated to a neutral pH composition, wherein such composition is then used to treat bone and promote bone growth and/or healing.
  • the PDGF utilized in the solutions is rh-PDGF-BB.
  • the pH of the PDGF containing solution may be altered to optimize the binding kinetics of PDGF to a matrix substrate or linker. If desired, the pH of the material equilibrates to adjacent material, the bound PDGF may become labile.
  • the pH of solutions comprising PDGF in some embodiments, can be controlled by the buffers recited herein.
  • Various proteins demonstrate different pH ranges in which they are stable. Protein stabilities are primarily reflected by isoelectric points and charges on the proteins. The pH range can affect the conformational structure of a protein and the susceptibility of a protein to proteolytic degradation, hydrolysis, oxidation, and other processes that can result in modification to the structure and/or biological activity of the protein.
  • solutions comprising PDGF can further comprise additional components, such as other biologically active agents.
  • solutions comprising PDGF can further comprise cell culture media, other stabilizing proteins such as albumin, antibacterial agents, protease inhibitors [e.g., ethylenediaminetetraacetic acid (EDTA), ethylene glycol-bis(beta-aminoethylether)-N, N,N',N'-tetraacetic acid (EGTA), aprotinin, ⁇ - aminocaproic acid (EACA), etc.] and/or other growth factors such as fibroblast growth factors (FGFs), epidermal growth factors (EGFs), transforming growth factors (TGFs), keratinocyte growth factors (KGFs), insulin-like growth factors (IGFs), hepatocyte growth factors (HGFs), bone morphogenetic proteins (BMPs), or other PDGFs including compositions of PDGF-AA, PDGF-BB, PDGF-AB,
  • EDTA ethylene
  • compositions of the present invention also comprise a biocompatible matrix in which to dispose the PDGF solutions and may also comprise a biocompatible binder either with or without addition of a biocompatible matrix.
  • a biocompatible matrix comprises a bone scaffolding material. It is to be understood that the terms bone scaffolding material and bone substituting agent are used interchangeably in the present application.
  • the bone scaffolding material provides the framework or scaffold for new bone and tissue growth to occur.
  • a bone scaffolding material has multidirectional and interconnected pores of varying diameters.
  • a bone scaffolding material comprises a plurality of pockets and non-interconnected pores in addition to the interconnected pores.
  • a bone scaffolding material in some embodiments, is one that can permanently or temporarily replace bone. Following implantation, the bone scaffolding material can be retained by the body or it can be resorbed by the body and replaced by bone.
  • a bone scaffolding material in some embodiments, comprises at least one calcium phosphate.
  • a bone scaffolding material can comprise a plurality of calcium phosphates.
  • Calcium phosphates suitable for use as a bone scaffolding material, in embodiments of the present invention have a calcium to phosphorus atomic ratio ranging from 0.5 to 2.0.
  • a bone scaffolding material comprises an allograft such as DFDBA, FDBA, or particulate DBM.
  • a bone scaffolding material comprises mineralized bone allograft, mineralized bone, mineralized deproteinized xenograft, or demineralized bone.
  • Non-limiting examples of calcium phosphates suitable for use as bone scaffolding materials comprise amorphous calcium phosphate, monocalcium phosphate monohydrate (MCPM), monocalcium phosphate anhydrous (MCPA), dicalcium phosphate dihydrate (DCPD), dicalcium phosphate anhydrous (DCPA), octacalcium phosphate (OCP), ⁇ -tricalcium phosphate, ⁇ -TCP, hydroxyapatite (OHAp), poorly crystalline hydroxapatite, tetracalcium phosphate (TTCP), heptacalcium decaphosphate, calcium metaphosphate, calcium pyrophosphate dihydrate, calcium pyrophosphate, carbonated calcium phosphate, hydroxyapatite, or derivatives or mixtures thereof.
  • MCPM monocalcium phosphate monohydrate
  • MCPA monocalcium phosphate anhydrous
  • DCPD dicalcium phosphate dihydrate
  • DCPA dicalcium phosphate anhydrous
  • OCP o
  • a bone scaffolding material comprises a polymeric material.
  • a polymeric scaffold in some embodiments, comprises collagen, polylactic acid, poly(L-lactide), poly(D,L-lactide), polyglycolic acid, poly(L-lactide-co-glycolide), poly(L-lactide-co-D,L- lactide), polyacrylate, polymethacrylate, polymethylmethacrylate, chitosan, or combinations or derivatives thereof.
  • a bone scaffolding material comprises porous structure.
  • Porosity is a desirable characteristic as it facilitates cell migration and infiltration into the scaffolding material so that the infiltrating cells can secrete extracellular bone matrix.
  • Porosity also provides access for vascularization.
  • Porosity also provides a high surface area for enhanced resorption and release of active substances as well as increased cell-matrix interaction.
  • a bone scaffolding material in some embodiments, can be sized and shaped prior to use.
  • the bone scaffolding material can be provided in a shape suitable for implantation.
  • Porous bone scaffolding materials can comprise pores having diameters ranging from about 1 ⁇ m to about 1 mm.
  • a bone scaffolding material comprises macropores having diameters ranging from about 100 ⁇ m to about 1 mm or greater. In another embodiment, a bone scaffolding material comprises mesopores having diameters ranging from about 10 ⁇ m to about 100 ⁇ m. In a further embodiment, a bone scaffolding material comprises micropores having diameters less than about 10 ⁇ m. Embodiments of the present invention contemplate bone scaffolding materials comprising macropores, mesopores, and micropores or any combination thereof.
  • a porous bone scaffolding material in one embodiment, has a porosity greater than about 25% or greater than about 40%. In another embodiment, a porous bone scaffolding material has a porosity greater than about 50%, greater than about 60%, greater than about 65%, greater than about 70%, greater than about 80%, or greater than about 85%. In a further embodiment, a porous bone scaffolding material has a porosity greater than about 90%. In some embodiments, a porous bone scaffolding material comprises a porosity that facilitates cell migration into the scaffolding material. In some embodiments, a bone scaffolding material comprises a plurality of particles. A bone scaffolding material, for example, can comprise a plurality of calcium phosphate particles.
  • Particles of a bone scaffolding material in some embodiments, can individually demonstrate any of the pore diameters and porosities provided here for the bone scaffolding material. In other embodiments, particles of a bone scaffolding material can form an association to produce a matrix having any of the pore diameters or porosities provided herein for the bone scaffolding material.
  • Bone scaffolding particles may be mm, ⁇ m, or submicron (nm) in size. Bone scaffolding particles, in one embodiment, have an average diameter ranging from about 1 ⁇ m to about 5 mm. In other embodiments, particles have an average diameter ranging from about 1 mm to about 2 mm, from about 1 mm to about 3 mm, or from about 250 ⁇ m to about 750 ⁇ m. Bone scaffolding particles, in another embodiment, have an average diameter ranging from about 100 ⁇ m to about 300 ⁇ m. In a further embodiment, bone scaffolding particles have an average diameter ranging from about 75 ⁇ m to about 300 ⁇ m.
  • bone scaffolding particles have an average diameter less than about 25 ⁇ m, less than about 1 ⁇ m, or less than about 1 mm. In some embodiments, scaffolding particles have an average diameter ranging from about 100 ⁇ m to about 5 mm or from about 100 ⁇ m to about 3 mm. In other embodiments, bone scaffolding particles have an average diameter ranging from about 250 ⁇ m to about 2 mm, from about 250 ⁇ m to about 1 mm, or from about 200 ⁇ m to about 3 mm. Particles may also be in the range of about 1 nm to about 1 ⁇ m, less than about 500 nm, or less than about 250 nm.
  • Bone scaffolding materials can be provided in a shape suitable for implantation (e.g., a sphere, a cylinder, or a block).
  • bone scaffolding materials are moldable, extrudable and/or injectable. Moldable, extrudable, and injectable bone scaffolding materials can facilitate efficient placement of compositions of the present invention in and around vertebral bodies.
  • bone scaffolding materials are flowable. Flowable bone scaffolding materials, in some embodiments, can be applied vertebral bodies through a syringe and needle or cannula. In some embodiments, bone scaffolding materials harden in vivo.
  • bone scaffolding materials are bioresorbable.
  • a bone scaffolding material in one embodiment, can be at least 30%, 40%, 50%, 60%, 70%, 75%, or 90% resorbed within one year subsequent to in vivo implantation.
  • a bone scaffolding material can be resorbed at least 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 75%, or 90% within 1, 3, 6, 9, 12, or 18 months of in vivo implantation.
  • a bone scaffolding material is greater than 90% resorbed within 1, 3, 6, 9, 12, or 18 months of in vivo implantation.
  • Bioresorbability will be dependent on: (1) the nature of the matrix material (i.e., its chemical make up, physical structure and size); (2) the location within the body in which the matrix is placed; (3) the amount of matrix material that is used; (4) the metabolic state of the patient (diabetic/non-diabetic, osteoporotic, smoker, old age, steroid use, etc.); (5) the extent and/or type of injury treated; and (6) the use of other materials in addition to the matrix such as other bone anabolic, catabolic and anti-catabolic factors.
  • Bone Scaffolding Comprising ⁇ -Tricalcium Phosphate ( ⁇ -TCP)
  • ⁇ -TCP ⁇ -Tricalcium Phosphate
  • TCP can comprise a porous structure having multidirectional and interconnected pores of varying diameters.
  • ⁇ -TCP comprises a plurality of pockets and non-interconnected pores of various diameters in addition to the interconnected pores.
  • the porous structure of ⁇ -TCP in one embodiment, comprises macropores having diameters ranging from about 100 ⁇ m to about 1 mm or greater, mesopores having diameters ranging from about 10 ⁇ m to about 100 ⁇ m, and micropores having diameters less than about 10 ⁇ m.
  • Macropores and micropores of the ⁇ -TCP can facilitate osteoinduction and osteoconduction while macropores, mesopores and micropores can permit fluid communication and nutrient transport to support bone regrowth throughout the ⁇ -TCP biocompatible matrix.
  • ⁇ -TCP in some embodiments, can have a porosity greater than 25% or greater than about 40%.
  • ⁇ -TCP can have a porosity greater than 50%, greater than about 60%, greater than about 65%, greater than about 70%, greater than about 75%, greater than about 80%, or greater than about 85%.
  • ⁇ -TCP can have a porosity greater than 90%.
  • ⁇ -TCP can have a porosity that facilitates cell migration into the ⁇ -TCP.
  • a ⁇ -TCP bone scaffolding material comprises ⁇ -TCP particles, ⁇ - TCP particles, in some embodiments, can individually demonstrate any of the pore diameters, pore structures, and porosities provided herein for scaffolding materials.
  • ⁇ -TCP particles in one embodiment have an average diameter ranging from about 1 ⁇ m to about 5 mm.
  • ⁇ -TCP particles have an average diameter ranging from about 1 mm to about 2 mm, from about 1 mm to about 3 mm, from about 100 ⁇ m to about 5 mm, from about 100 ⁇ m to about 3 mm, from about 250 ⁇ m to about 2 mm, from about 250 ⁇ m to about 750 ⁇ m, from about 250 ⁇ m to about 1 mm, from about 250 ⁇ m to about 2 mm, or from about 200 ⁇ m to about 3 mm.
  • ⁇ -TCP particles have an average diameter ranging from about 100 ⁇ m to about 300 ⁇ m. In some embodiments, ⁇ -TCP particles have an average diameter ranging from about 75 ⁇ m to about 300 ⁇ m.
  • ⁇ -TCP particles have an average diameter of less than about 25 ⁇ m, less than about 1 ⁇ m, or less than about 1 mm. In some embodiments, ⁇ -TCP particles have an average diameter ranging from about 1 nm to about 1 ⁇ m. In a further embodiment, ⁇ -TCP particles have an average diameter less than about 500 nm or less than about 250 nm.
  • a biocompatible matrix comprising a ⁇ -TCP bone scaffolding material in some embodiments, can be provided in a shape suitable for implantation (e.g., a sphere, a cylinder, or a block).
  • a ⁇ -TCP bone scaffolding material can be moldable, extrudable, and/or flowable thereby facilitating application of the matrix to vertebral bodies.
  • Flowable matrices may be applied through syringes, tubes, cannulas, or spatulas.
  • a ⁇ -TCP bone scaffolding material is bioresorbable.
  • a ⁇ -TCP bone scaffolding material can be at least 30%, 40%, 50%, 60%, 65%, 70%, 75%, 80%, or 85% resorbed one year subsequent to in vivo implantation.
  • a ⁇ -TCP bone scaffolding material can be greater than 90% resorbed one year subsequent to in vivo implantation.
  • a biocompatible matrix comprises a bone scaffolding material and a biocompatible binder.
  • Bone scaffolding materials in embodiments of a biocompatible matrix further comprising a biocompatible binder are consistent with those provided hereinabove.
  • Biocompatible binders can comprise materials operable to promote cohesion between combined substances.
  • a biocompatible binder for example, can promote adhesion between particles of a bone scaffolding material in the formation of a biocompatible matrix.
  • the same material may serve as both a scaffolding material.
  • polymeric materials described herein such as collagen and chitosan may serve as both scaffolding material and a binder.
  • Biocompatible binders in some embodiments, can comprise collagen, polysaccharides, nucleic acids, carbohydrates, proteins, polypeptides, poly( ⁇ -hydroxy acids), poly(lactones), poly(amino acids), poly(anhydrides), polyurethanes, poly(orthoesters), poly(anhydride-co- imides), poly(orthocarbonates), poly( ⁇ -hydroxy alkanoates), poly(dioxanones), poly(phosphoesters), polylactic acid, poly(L-lactide) (PLLA), poly(D,L-lactide) (PDLLA), polyglycolide (PGA), poly(lactide-co-glycolide (PLGA), poly(L-lactide-co-D,L-lactide), poly(D,L-lactide-co-trimethylene carbonate), polyglycolic acid, polyhydroxybutyrate (PHB), poly( ⁇ -caprolactone), poly( ⁇ -valerolactone), poly( ⁇ -butyrolactone
  • Biocompatible binders in other embodiments, can comprise alginic acid, arabic gum, guar gum, xantham gum, gelatin, chitin, chitosan, chitosan acetate, chitosan lactate, chondroitin sulfate, N,O-carboxymethyl chitosan, a dextran (e.g., ⁇ -cyclodextrin, ⁇ -cyclodextrin, ⁇ - cyclodextrin, or sodium dextran sulfate), fibrin glue, lecithin, phosphatidylcholine derivatives, glycerol, hyaluronic acid, sodium hyaluronate, a cellulose (e.g., methylcellulose, carboxymethylcellulose, hydroxypropyl methylcellulose, or hydroxyethyl cellulose), a glucosamine, a proteoglycan, a starch (e.g., hydroxyethyl
  • a biocompatible binder is water-soluble.
  • a water-soluble binder can dissolve from the biocompatible matrix shortly after its implantation, thereby introducing macroporosity into the biocompatible matrix. Macroporosity, as discussed herein, can increase the osteoconductivity of the implant material by enhancing the access and, consequently, the remodeling activity of the osteoclasts and osteoblasts at the implant site.
  • a biocompatible binder can be present in a biocompatible matrix in an amount ranging from about 5 weight percent to about 50 weight percent of the matrix. In other embodiments, a biocompatible binder can be present in an amount ranging from about 10 weight percent to about 40 weight percent of the biocompatible matrix. In another embodiment, a biocompatible binder can be present in an amount ranging from about 15 weight percent to about 35 weight percent of the biocompatible matrix. In a further embodiment, a biocompatible binder can be present in an amount of about 20 weight percent of the biocompatible matrix. In another embodiment, a biocompatible binder can be present in a biocompatible matrix in an amount greater than about 50 weight percent or 60 weight percent of the matrix. In one embodiment, a biocompatible binder can be present in a biocompatible matrix in an amount up to about 99 weight percent of the matrix.
  • a biocompatible matrix comprising a bone scaffolding material and a biocompatible binder can be flowable, moldable, and/or extrudable.
  • a biocompatible matrix can be in the form of a paste or putty.
  • a biocompatible matrix in the form of a paste or putty in one embodiment, can comprise particles of a bone scaffolding material adhered to one another by a biocompatible binder.
  • a biocompatible matrix in paste or putty form can be molded into the desired implant shape or can be molded to the contours of the implantation site.
  • a biocompatible matrix in paste or putty form can be injected into an implantation site with a syringe or cannula.
  • a biocompatible matrix in paste or putty form does not harden and retains a flowable and moldable form subsequent to implantation.
  • a paste or putty can harden subsequent to implantation, thereby reducing matrix flowability and moldability.
  • a biocompatible matrix comprising a bone scaffolding material and a biocompatible binder in some embodiments, can also be provided in a predetermined shape including a block, sphere, or cylinder or any desired shape, for example a shape defined by a mold or a site of application.
  • a biocompatible matrix comprising a bone scaffolding material and a biocompatible binder in some embodiments, is bioresorbable.
  • a biocompatible matrix in such embodiments, can be resorbed within one year of in vivo implantation.
  • a biocompatible matrix comprising a bone scaffolding material and a biocompatible binder can be resorbed within 1, 3, 6, or 9 months of in vivo implantation.
  • a biocompatible matrix comprising a scaffolding material and a biocompatible binder can be resorbed within 1, 3, or six years of in vivo implantation.
  • Bioresorbablity will be dependent on: (1) the nature of the matrix material (i.e., its chemical make up, physical structure and size); (2) the location within the body in which the matrix is placed; (3) the amount of matrix material that is used; (4) the metabolic state of the patient (diabetic/non-diabetic, osteoporotic, smoker, old age, steroid use, etc.); (5) the extent and/or type of injury treated; and (6) the use of other materials in addition to the matrix such as other bone anabolic, catabolic and anti-catabolic factors.
  • a biocompatible matrix can comprise a ⁇ -TCP bone scaffolding material and a biocompatible collagen binder.
  • ⁇ -TCP bone scaffolding materials suitable for combination with a collagen binder are consistent with those provided hereinabove.
  • a collagen binder in some embodiments, can comprise any type of collagen, including Type I, Type II, and Type III collagens.
  • a collagen binder comprises a mixture of collagens, such as a mixture of Type I and Type II collagen.
  • a collagen binder is soluble under physiological conditions.
  • Other types of collagen present in bone or musculoskeletal tissues may be employed. Recombinant, synthetic and naturally occurring forms of collagen may be used in the present invention.
  • a biocompatible matrix can comprise a plurality of ⁇ - TCP particles adhered to one another with a collagen binder.
  • ⁇ -TCP particles for combination with a collagen binder have an average diameter ranging from about 1 ⁇ m to about 5 mm.
  • ⁇ -TCP particles have an average diameter ranging from about 1 mm to about 2 mm, from about 1 mm to about 3 mm, from about 100 ⁇ m to about 5 mm, from about 100 ⁇ m to about 3 mm, from about 250 ⁇ m to about 2 mm, from about 250 ⁇ m to about 750 ⁇ m, from about 250 ⁇ m to about 1 mm, from about 250 ⁇ m to about 2 mm, or from about 200 ⁇ m to about 3 mm.
  • ⁇ -TCP particles have an average diameter ranging from about 100 ⁇ m to about 300 ⁇ m. In some embodiments, ⁇ -TCP particles have an average diameter ranging from about 75 ⁇ m to about 300 ⁇ m.
  • ⁇ -TCP particles have an average diameter of less than about 25 ⁇ m, less than about 1 ⁇ m, or less than about 1 mm. In some embodiments, ⁇ -TCP particles have an average diameter ranging from about 1 nm to about 1 ⁇ m. In a further embodiment, ⁇ -TCP particles have an average diameter less than about 500 nm or less than about 250 nm.
  • ⁇ -TCP particles in some embodiments, can be adhered to one another by the collagen binder so as to produce a biocompatible matrix having a porous structure. In some embodiments, the porous structure of a biocompatible matrix comprising ⁇ -TCP particles and a collagen binder demonstrates multidirectional and interconnected pores of varying diameters. In some embodiments, a the biocompatible matrix comprises a plurality of pockets and non- interconnected pores of various diameters in addition to the interconnected pores.
  • a biocompatible matrix comprising ⁇ -TCP particles and a collagen binder can comprise pores having diameters ranging from about 1 ⁇ m to about 1 mm.
  • a biocompatible matrix comprising ⁇ -TCP particles and a collagen binder can comprise macropores having diameters ranging from about 100 ⁇ m to about 1 mm or greater, mesopores having diameters ranging from about 10 ⁇ m to 100 ⁇ m, and micropores having diameters less than about 10 ⁇ m.
  • a biocompatible matrix comprising ⁇ -TCP particles and a collagen binder can have a porosity greater than about 25% or greater than about 40%.
  • the biocompatible matrix can have a porosity greater than about 50%, greater than about 65%, greater than about 70%, greater than about 75%, greater than about 80%, or greater than about 85%. In a further embodiment, the biocompatible matrix can have a porosity greater than about 90%. In some embodiments, the biocompatible matrix can have a porosity that facilitates cell migration into the matrix.
  • the ⁇ -TCP particles can individually demonstrate any of the pore diameters, pore structures, and porosities provided herein for a biocompatible matrix comprising the ⁇ -TCP and collagen binder.
  • a biocompatible matrix comprising ⁇ -TCP particles can comprise a collagen binder in an amount ranging from about 5 weight percent to about 50 weight percent of the matrix.
  • a collagen binder can be present in an amount ranging from about 10 weight percent to about 40 weight percent of the biocompatible matrix.
  • a collagen binder can be present in an amount ranging from about 15 weight percent to about 35 weight percent of the biocompatible matrix.
  • a collagen binder can be present in an amount of about 20 weight percent of the biocompatible matrix.
  • a biocompatible matrix comprising ⁇ -TCP particles and a collagen binder can be flowable, moldable, and/or extrudable.
  • the biocompatible matrix can be in the form of a paste or putty.
  • a paste or putty can be molded into the desired implant shape or can be molded to the contours of the implantation site.
  • a biocompatible matrix in paste or putty form comprising ⁇ -TCP particles and a collagen binder can be injected into an implantation site with a syringe or cannula.
  • a biocompatible matrix in paste or putty form comprising ⁇ -TCP particles and a collagen binder can retain a flowable and moldable form when implanted.
  • the paste or putty can harden subsequent to implantation, thereby reducing matrix flowability and moldability.
  • a biocompatible matrix comprising ⁇ -TCP particles and a collagen binder in some embodiments, can be provided in a predetermined shape such as a block, sphere, or cylinder.
  • a biocompatible matrix comprising ⁇ -TCP particles and a collagen binder can be resorbable.
  • a biocompatible matrix comprising ⁇ -TCP particles and a collagen binder can be at least 75% resorbed one year subsequent to in vivo implantation.
  • a biocompatible matrix comprising ⁇ -TCP particles and a collagen binder can be greater than 90% resorbed one year subsequent to in vivo implantation.
  • a solution comprising PDGF can be disposed in a biocompatible matrix to produce a composition for treating structures of the vertebral column according to embodiments described herein.
  • compositions comprising a PDGF solution disposed in a biocompatible matrix for promoting bone formation in a vertebral body and preventing or reducing the likelihood of vertebral compression fractures, as described herein, further comprise at least one contrast agent.
  • Contrast agents comprise cationic contrast agents, anionic contrast agents, nonionic contrast agents or mixtures thereof.
  • contrast agents comprise radiopaque contrast agents.
  • Radiopaque contrast agents comprise iodo-compounds including (S)-N,N'-bis[2-hydroxy-l- (hydroxymethyl)-ethyl]-2,4,6-triiodo-5-lactamidoisophthalamide (Iopamidol) and derivatives thereof.
  • a method for producing such compositions comprises providing a solution comprising PDGF, providing a biocompatible matrix, and disposing the solution in the biocompatible matrix.
  • PDGF solutions and biocompatible matrices suitable for combination are consistent with those described hereinabove.
  • a PDGF solution can be disposed in a biocompatible matrix by soaking the biocompatible matrix in the PDGF solution.
  • a PDGF solution in another embodiment, can be disposed in a biocompatible matrix by injecting the biocompatible matrix with the PDGF solution.
  • injecting a PDGF solution can comprise disposing the PDGF solution in a syringe and expelling the PDGF solution into the biocompatible matrix to saturate the biocompatible matrix.
  • the PDGF is absorbed into the pores of the biocompatible matrix. In some embodiments, the PDGF is adsorbed onto one or more surfaces of the biocompatible matrix, including surfaces within pores of the biocompatible matrix.
  • the biocompatible matrix can be in a predetermined shape, such as a brick or cylinder, prior to receiving a PDGF solution. Subsequent to receiving a PDGF solution, the biocompatible matrix can have a paste or putty form that is flowable, extrudable, and/or injectable. In other embodiments, the biocompatible matrix can already demonstrate a flowable paste or putty form prior to receiving a solution comprising PDGF. Flowable, extrudable, and/or injectable forms of compositions comprising a PDGF solution disposed in a biocompatible matrix are advantageous for use in methods of the present application as they can applied to vertebral bodies with syringes and/or cannulas.
  • methods of producing compositions for promoting bone formation in vertebral bodies and preventing or decreasing the likelihood of compression fractures in vertebral bodies further comprise providing at least one contrast agent and disposing the at least one contrast agent in the biocompatible matrix.
  • disposing at least one contrast agent in a biocompatible matrix comprises combining the at least one contrast agent with a PDGF solution and injecting the biocompatible matrix with the PDGF/contrast agent solution.
  • disposing at least one contrast agent in a biocompatible matrix comprises combining the at least one contrast agent with a PDGF solution and soaking the biocompatible matrix in the PDGF/contrast agent solution.
  • a contrast agent is disposed in a biocompatible matrix independent of the PDGF solution.
  • Contrast agents facilitate placement or application of compositions of the present invention in and around vertebral bodies.
  • Contrast agents comprise cationic contrast agents, anionic contrast agents, nonionic contrast agents, or mixtures thereof.
  • contrast agents comprise radiopaque contrast agents.
  • Radiopaque contrast agents comprise iodo-compounds including (S)-N ,N'-bis[2-hydroxy-l-(hydroxymethyl)-ethyl]-2,4,6- triiodo-5-lactamidoisophthalamide (Iopamidol) and derivatives thereof.
  • compositions Further Comprising Biologically Active Agents
  • compositions of the present invention can further comprise one or more biologically active agents in addition to PDGF.
  • biologically active agents that can be incorporated into compositions of the present invention, in addition to PDGF can comprise organic molecules, inorganic materials, proteins, peptides, nucleic acids (e.g., genes, gene fragments, small interfering ribonucleic acids [si-RNAs], gene regulatory sequences, nuclear transcriptional factors, and antisense molecules), nucleoproteins, polysaccharides (e.g., heparin), glycoproteins, and lipoproteins.
  • nucleic acids e.g., genes, gene fragments, small interfering ribonucleic acids [si-RNAs], gene regulatory sequences, nuclear transcriptional factors, and antisense molecules
  • nucleoproteins e.g., genes, gene fragments, small interfering ribonucleic acids [si-RNAs], gene regulatory sequences, nuclear transcriptional factors, and antisense molecules
  • Non-limiting examples of biologically active compounds that can be incorporated into compositions of the present invention including, e.g., anti-cancer agents, antibiotics, analgesics, anti-inflammatory agents, immunosuppressants, enzyme inhibitors, antihistamines, hormones, muscle relaxants, prostaglandins, trophic factors, osteoinductive proteins, growth factors, and vaccines, are disclosed in U.S. Patent Application Serial No. 11/159,533 (Publication No: 20060084602).
  • biologically active compounds that can be incorporated into compositions of the present invention include osteostimulatory factors such as insulin-like growth factors, fibroblast growth factors, or other PDGFs.
  • biologically active compounds that can be incorporated into compositions of the present invention preferably include osteoinductive and osteostimulatory factors such as bone morphogenetic proteins (BMPs), BMP mimetics, calcitonin, or calcitonin mimetics, statins, statin derivatives, fibroblast growth factors, insulin-like growth factors, growth differentiating factors, small molecule or antibody blockers of Wnt antagonists (e.g. sclerostin, DKK, soluble Wnt receptors), and/or parathyroid hormone.
  • BMPs bone morphogenetic proteins
  • BMP mimetics such as bone morphogenetic proteins (BMPs), BMP mimetics, calcitonin, or calcitonin mimetics
  • statins such as bone morphogenetic proteins (BMPs), BMP mimetics, calcitonin, or calcitonin mimetics
  • statins such as statins, statin derivatives, fibroblast growth factors, insulin-like growth factors, growth
  • factors also include protease inhibitors, as well as osteoporotic treatments that decrease bone resorption including bisphosphonates, teriparadide, and antibodies to the activator receptor of the NF-kB ligand (RANK) ligand.
  • protease inhibitors as well as osteoporotic treatments that decrease bone resorption including bisphosphonates, teriparadide, and antibodies to the activator receptor of the NF-kB ligand (RANK) ligand.
  • RANK NF-kB ligand
  • Standard protocols and regimens for delivery of additional biologically active agents are known in the art. Additional biologically active agents can introduced into compositions of the present invention in amounts that allow delivery of an appropriate dosage of the agent to the implant site. In most cases, dosages are determined using guidelines known to practitioners and applicable to the particular agent in question.
  • the amount of an additional biologically active agent to be included in a composition of the present invention can depend on such variables as the type and extent of the condition, the overall health status of the particular patient, the formulation of the biologically active agent, release kinetics, and the bioresorbability of the biocompatible matrix. Standard clinical trials may be used to optimize the dose and dosing frequency for any particular additional biologically active agent.
  • a composition of the present invention can further comprise the addition of additional bone grafting materials with PDGF including autologous bone marrow, autologous platelet extracts, allografts, synthetic bone matrix materials, xenografts, and derivatives thereof.
  • additional bone grafting materials with PDGF including autologous bone marrow, autologous platelet extracts, allografts, synthetic bone matrix materials, xenografts, and derivatives thereof.
  • the present invention provides methods for promoting bone formation in a vertebral body comprising providing a composition comprising a PDGF solution disposed in a biocompatible matrix and applying the composition to at least one vertebral body.
  • the composition can be applied to a plurality of vertebral bodies. Applying the composition, in some embodiments, comprises injecting at least one vertebral body with the composition.
  • Compositions of the present invention are injected into the cancellous bone of a vertebral body.
  • Vertebral bodies in some embodiments, comprise thoracic vertebral bodies, lumbar vertebral bodies, or combinations thereof.
  • Vertebral bodies in some embodiments, comprise cervical vertebral bodies, coccygeal vertebral bodies, the sacrum, or combinations thereof.
  • the present invention provides methods for preventing or decreasing the likelihood of vertebral compression fractures, including secondary vertebral compression fractures by strengthening vertebrae.
  • Preventing or decreasing the likelihood of vertebral compression fractures comprises providing a composition comprising a PDGF solution disposed in a biocompatible matrix and applying the composition to at least one vertebral body.
  • applying the composition to at least one vertebral body comprises injecting the composition into the at least one vertebral body.
  • a composition of the present invention is applied to a second vertebral body subsequent to vertebroplasty or kyphoplasty of a first vertebral body.
  • the second vertebral body is adjacent to the first vertebral body.
  • the second vertebral body is not adjacent to the first vertebral body.
  • a composition of the present invention is applied to a third vertebral body subsequent to vertebroplasty or kyphoplasty of a first vertebral body.
  • the third vertebral body is adjacent to the first vertebral body.
  • the third vertebral body is not adjacent to the first vertebral body.
  • Embodiments of the present invention additionally contemplate application of compositions provided herein to a plurality of vertebral bodies, including high risk vertebral bodies, subsequent to vertebroplasty or kyphoplasty of a first vertebral body.
  • first, second, and third vertebral bodies do not refer to any specific position in the vertebral column as methods for inhibiting vertebral compression fractures, including secondary compression fractures, can be applied to all types of vertebral bodies including thoracic vertebral bodies, lumbar vertebral bodies, cervical vertebral bodies, coccygeal vertebral bodies, and the sacrum.
  • methods for promoting bone formation in vertebral bodies and preventing or decreasing the likelihood of compression fractures of vertebral bodies further comprise providing at least one pharmaceutical composition in addition to the composition comprising a PDGF solution disposed in a biocompatible matrix and administering the at least one pharmaceutical composition locally and/or systemically.
  • the at least one pharmaceutical composition in some embodiments, comprises vitamins, such as vitamin D3, calcium supplements, or any osteoclast inhibitor known to one of skill in the art, including bisphosphonates.
  • the at least one pharmaceutical composition is administered locally.
  • the at least one pharmaceutical composition can be incorporated into the biocompatible matrix or otherwise disposed in and around a vertebral body.
  • the at least one pharmaceutical composition is administered systemically to a patient.
  • the at least one pharmaceutical composition is administered orally to a patient.
  • the at least one pharmaceutical composition is administered intravenously to a patient.
  • a composition comprising a solution of PDGF and a biocompatible matrix was prepared according to the following procedure.
  • a pre-weighed block of biocompatible matrix comprising ⁇ -TCP and collagen was obtained.
  • the ⁇ -TCP comprised ⁇ -TCP particles having an average diameter ranging from about 100 ⁇ m to about 300 ⁇ m.
  • the ⁇ -TCP particles were formulated with about 20% weight percent soluble bovine type I collagen binder.
  • Such a ⁇ -TCP/collagen biocompatible matrix can be commercially obtained from Kensey Nash (Exton, Pennsylvania).
  • rhPDGF-BB is commercially available from Novartis Corporation at a stock concentration of 10 mg/ml (i.e., Lot # QA2217) in a sodium acetate buffer.
  • the rhPDGF-BB is produced in a yeast expression system by Chiron Corporation and is derived from the same production facility as the rhPDGF-BB that is utilized in the products REGRANEX, (Johnson & Johnson) and GEM 21 S (BioMimetic Therapeutics) which have been approved for human use by the United States Food and Drug Administration. This rhPDGF-BB is also approved for human use in the European Union and Canada.
  • the rhPDGF-BB solution was diluted to 0.3 mg/ml in the acetate buffer.
  • the rhPDGF-BB solution can be diluted to any desired concentration according to embodiments of the present invention, including 1.0 mg/ml.
  • a ratio of about 3 ml of rhPDGF-BB solution to about 1 g dry weight of the ⁇ - TCP/collagen biocompatible matrix was used to produce the composition.
  • the rhPDGF-BB solution was expelled on the biocompatible matrix with a syringe, and the resulting composition was blended into a paste for placement into a syringe for subsequent injection into a vertebral body.
  • This prospective, randomized, controlled, single-center clinical trial is to evaluate the efficacy of compositions comprising a PDGF solution disposed in a tricalcium phosphate matrix for inhibiting secondary compression fractures in high risk vertebral bodies (HVBs) at the time of kyphoplasty of vertebral compression fractures. Comparisons are made between vertebral bodies treated with a ⁇ -tricalcium phosphate + rhPDGF-BB composition and untreated vertebral bodies. The present study is a pilot, clinical trial to support the proof-or-principle of ⁇ -TCP + rh-PDGF- BB to prevent or decrease the likelihood of secondary vertebral compression fractures by increased bone formation in HVBs.
  • the study is performed on up to a total of 10 patients requiring prophylactic treatment of
  • HVBs at the time of kyphoplasty. Potential patients are screened to determine if they meet the inclusion and exclusion criteria If all entry criteria are achieved, the potential patients are invited to participate in the clinical trial. All patients considered for entry into the study are documented on the Screening Log and reasons for exclusion are recorded.
  • a total of 10 patients are enrolled and treated in the present study.
  • a first vertebral body adjacent to the kyphoplasty of each patient is injected with 3.0 ml of a composition of ⁇ -TCP +
  • the second vertebral body adjacent to the kyphoplasty remains untreated and serves as a control.
  • the treated vertebral body may be either cranial or caudal to the kyphoplasty and is determined randomly.
  • QCT quantitative computed tomography
  • the primary endpoint is the bone density at 12 weeks post-operatively measured by QCT scans. Secondary endpoints include subject pain and quality of life assessments.
  • the investigator identifies and qualifies the two levels to be treated with prophylactic bone augmentation. If two (2) qualified vertebral bodies are not available for treatment, as determined at the time of surgery, the patient is considered a screen failure and not enrolled into the study.
  • the investigator Upon identification of the two HVBs, the investigator requests that the randomization code be opened to determine the study treatment administered.
  • the randomization code specifies treatment with the ⁇ -TCP + rhPDGF composition either proximally or distally in relation to the level treated with kyphoplasty.
  • the other HVB remains untreated.
  • the ⁇ -TCP + rhPDGF composition is mixed according to the procedure provided in Example 1. Once mixed, the paste is loaded into a syringe for injection using aseptic technique. Once the ⁇ -TCP +rhPDGF composition is mixed, the clinician waits about 10 minutes prior to implantation. A new sterile mixing device (spatula) is used for each mix. The investigator directs the assistant who performs the mixing to record the cumulative amount of implanted composition, as well as the residual amount of composition not implanted. The amount of composition is calculated and documented using qualitative relative measurements (1/3, 2/3, All).
  • JAMSHID I® needle available from Cardinal Health of Dublin, Ohio is inserted through an extrapedicular approach into the vertebral bodies requiring prophylactic treatment.
  • the wire is passed through the JAMSHIDI® needle and the JAMSHIDI® needle through the stylet over the wire.
  • the appropriate mixed preparation is injected into the subject vertebral body. Care should be taken to minimize leakage of the paste outside of the vertebral body.
  • Contrast agents can assist in identifying the leakage of the paste outside the vertebral body.
  • Figure 1 illustrates a syringe and related apparatus penetrating tissue overlaying a vertebral body to deliver a composition of the present invention to the vertebral body.
  • Figure 2 is a radiograph illustrating injection of a composition of the present invention into the vertebral body of the L3 vertebra according to one embodiment.
  • the instrumentation is removed. Thorough irrigation and standard wound closure techniques are employed.
  • QCT Quantitative Computed Tomography
  • Vertebral bodies injected with a ⁇ -TCP + rhPDGF composition are expected to display increased bone mineral density (BMD) in comparison to untreated vertebral bodies.
  • BMD bone mineral density
  • Increased bone mineral density in a vertebral body can render the vertebral body less susceptible to fractures including secondary fractures induced by kyphoplasty/vertebroplasty operations.
  • EXAMPLE 3 Method of Inhibiting Vertebral Compression Fractures in Osteoporotic Individuals
  • a method of inhibiting vertebral compression fractures in osteoporotic individuals comprises promoting bone formation in vertebral bodies through treatment with compositions comprising a PDGF solution disposed in a biocompatible matrix such as ⁇ -tricalcium phosphate.
  • compositions of the present invention are mixed in accordance with that provided in
  • Example 1 The concentration of PDGF in the PDGF solutions ranges from 0.3 mg/ml to 1.0 mg/ml. Once mixed, the composition is loaded into a syringe for injection using aseptic technique. The surgeon waits about 10 minutes prior to implantation. A new sterile mixing device (spatula) is used for each mix.
  • spatula sterile mixing device
  • the JAMSHIDI® needle is inserted through an extrapedicular approach into the vertebral bodies requiring prophylactic treatment.
  • Vertebral bodies requiring prophylactic treatment comprise high risk vertebral bodies including vertebral bodies T5 through T 12 and Ll through L4.
  • the wire is passed through the JAMSHIDI® needle and the JAMSHIDI® needle through the stylet over the wire
  • the mixed composition is injected into the subject vertebral body. Care is taken to minimize leakage of the paste outside of the vertebral body.
  • a plurality of vertebral bodies are treated according to the present example. Osteoporotic patients receiving this treatment have a lower incidence of vertebral compression fractures than untreated osteoporotic patients.
  • This study evaluated the safety of implanting injectable rhPDGF-BB/collagen/D-TCP material in a paravertebral intramuscular site adjacent to the spine of rabbits.
  • the animals were observed for signs of neurotoxicity, and the implant sites with adjacent vertebral bodies and spinal cord were examined histologically to document tissue-specific responses to the material.
  • the study protocol and animal care was approved by the local IACUC and conducted according to AAALAC guidelines. Twelve (12) na ⁇ ve, female, albino New Zealand rabbits weighing >2.5 kg were assigned to one of 4 groups: 0.3 mg/ml PDGF; 1.0 mg/ml PDGF; rubber; or acetate buffer. PDGF treated rabbits received 0.2 cc implants of appropriately concentrated rhPDGF-BB in matrix injected into a 1 cm pocket in the right paravertebral muscle adjacent to the L4-L5 vertebral bodies while high density polyethylene (HDPE) was implanted in a similar incision in the left paravertebral muscles near L2-L3 of the same animals.
  • HDPE high density polyethylene
  • Rabbits in the sodium acetate buffer group received sodium acetate buffer in place of the PDGF+matrix implant, while those in the rubber group received only rubber in the right paravertebral muscle.
  • One rabbit in each group was sacrificed at 29, 90, and 180 days post-surgery. Body weights were measured prior to surgery and biweekly following surgery for the duration of the study. Radiographs were taken prior to surgery, immediately following surgery, and immediately prior to sacrifice. Digital photography of the surgical sites was performed during surgery and at the study end points. Weekly clinical observations of the implant sites were recorded for signs of erythema, edema, and inflammation and for signs of neurotoxicity, such as ambulatory changes. At necropsy, each implant site along with the adjacent vertebral body and spinal cord were harvested en bloc, fixed in formalin, and prepared for decalcified, paraffin embedded histopathological analysis.
  • rhPDGF-BB dosages of rhPDGF-BB tested in this study included 0.3 mg/ml and 1.0 mg/ml in 20 mM sodium acetate buffer, pH 6.0 +/- 0.5.
  • the matrix material consisted of 20% lyophilized bovine type I collagen and 80% D-TCP with a particle size of 100-300 Dm (Kensey Nash Corporation).
  • Negative control material consisted of high-density polyethylene (HDPE) and positive control material consisted of black rubber.
  • HDPE high-density polyethylene
  • control material consisted of black rubber.
  • the rhPDGF- BB and control solutions were mixed with matrix material in a 3 : 1 liquid to mass ratio.
  • the PDGF solution was allowed to saturate the material for about 2 minutes then was manually mixed for about 3 minutes to generate a paste-like consistency.
  • the homogeneous distribution of rhPDGF-BB throughout the mixed material using this mixing technique was confirmed by eluting the PDGF from samples of similar mass and then quantifying the PDGF by ELISA (R&D Systems).
  • NC Negative Control
  • MGC multinucleated giant cells
  • the animals were imaged and analyzed using radiography, quantitative computed tomography (QCT), magnetic resonance imaging (MRI) techniques, terminal histology and non-GLP microcomputed tomography (microCT).
  • QCT quantitative computed tomography
  • MRI magnetic resonance imaging
  • microCT non-GLP microcomputed tomography
  • Each animal of Group I received an injection of about 0.5 cc of a 1.0 mg/ml rhPDGF-BB + collagen/ ⁇ -TCP (matrix) composition into each of the T12, L2 and L4 vertebral bodies.
  • the 1.0 mg/ml rhPDGF- BB + collagen/ ⁇ -TCP (matrix) compositions were prepared as set forth in Example 1 hereinabove.
  • Each animal of Group II received an injection of about 0.5 cc of a sodium acetate buffer + collagen/ ⁇ -TCP (matrix) composition into each of the T12, L2, and L4 vertebral bodies.
  • Animals were assigned to one of two surgery days (Day I or Day II). For each animal, a coin flip determined assignment into the Day I group or the Day II group. This process was continued until each of the days was filled with three animals. The animal numbers, their dosing group assignments, and surgery days were recorded.
  • the animal treatment groups were known to the study monitors and study director. The radiologists and histopathologist were blind to the treatment groups.
  • Body weights were measured at the initial health check, prior to surgery, and prior to follow up radiographs. Food was withheld prior to sedation and subsequent body weight measurements. Food Consumption
  • Non-GLP digital photographs were taken of the injection sites pre-operatively, immediately post-operatively, and at 1, 3, 6, and 9 months post-operative Iy.
  • Anteroposterior and lateral radiographs were taken pretreatment and immediately following surgery as well as at about 1, 3, 6, and 9 months post-operatively.
  • the animals were placed on their backs in supine position with their legs supported.
  • For lateral radiographs the animals were positioned lying on their left sides with arms and legs supported. Energy (kV) and intensity (mA) settings for each position and animal were recorded.
  • Non-GLP fluorographs were captured intraoperatively before, during, and after injection of the test and control articles into the vertebrae of the animals. Fluorographs were not assessed as an outcome of this study, but enable the surgeon to accurately insert the introduction needle into the vertebral bodies during surgery.
  • Magnetic resonance imaging was performed to image the spine of each animal pre- operatively and within 4 to 10 days post-operatively. MRI was additionally performed to image the spine of each animal at about 1, 3, 6, and 9 months post-operatively. MRI sessions consisted of Tl and T2 -weighted scans.
  • Quantitative computed tomography imaging was performed to image the spine of each animal pre-operatively and within 4 to 10 days post-operatively.
  • QCT was additionally performed to image the spine of each animal at about 1, 3, 6, and 9 months post-operatively.
  • Scans consisted of a series of contiguous cross-sectional slices of the torso from the caudal endplate of the 11 th thoracic vertebrae to the cranial endplate of the sacrum.
  • the evaluation software created a z-stack of the individual slices and ROFs before extracting the volumetric ROI and calculating volumetric density in arbitrary units derived from the gray-scale intensity in the images and a percent change from the baseline scans was calculated.
  • One-way repeated measures ANOVA with Tukey's post-hoc test was used to determine the presence of any statistically significant changes in vBMD for animals of Group I and Group II from pre-surgical or 1 wk post- surgical to the conclusion of the study.
  • the radiographs, MRI, and QCT images were evaluated by one board certified clinical radiologist and one qualified associate to provide a consensus assessment of the neuropathological, osteopathological and surrounding soft tissue pathological outcomes resulting from the treatments of the vertebrae.
  • the evaluation consisted of a qualitative examination of each image for abnormalities of the bone and of the neural tissues and adjacent surrounding soft tissues.
  • the radiologist followed the Radiology Assessment Protocol to evaluate the radiology data.
  • a complete necropsy is conducted under the supervision of the study pathologist on the sacrificed animals in a moribund or diseased condition during the study to determine the cause and/or nature of the moribund or diseased condition.
  • a standard necropsy includes an examination of external surfaces and orifices, extremities, body cavities, and internal organ/tissues. All of the treated vertebrae are collected and are examined for abnormalities. A brief morphologic description of all macroscopic abnormalities is recorded on individual necropsy forms.
  • tissue and organs are obtained at sacrifice and are preserved in 10% neutral-buffered formalin (except for the eyes, which were preserved in Bouin's Solution for optimum fixation). Each tissue or organ specimen is then embedded in paraffin for preservation purposes and is archived at a sponsor-approved site or used to help determine the cause of death.
  • T12 thru L6 treated and adjacent untreated vertebrae (T12 thru L6) are individually harvested en bloc including the spinal cord and spinal canal and are appropriately identified as to the treatment received.
  • the T 12 vertebral body is identified by leaving a minimum of 2 cm of the ribs attached to the bone. All bone specimens are placed in formalin fixative in preparation for plastic embedding.
  • Vertebral bodies injected with a composition comprising a rhPDGF-BB solution disposed in a ⁇ -TCP/collagen matrix displayed the formation of normal bone with no adverse neurotoxic effects.
  • soft tissues adjacent to vertebral bodies receiving a composition comprising a rhPDGF-BB solution disposed in a ⁇ -TCP/collagen matrix did not demonstrate abnormalities resulting from the administration of the rh-PDGF/matrix composition.
  • FIG. 4 illustrates percent change in volumetric bone mineral density (vBMD) for vertebral bodies of animals of Group I and Group II.
  • vBMD volumetric bone mineral density
  • Each data point in Figure 4 represents an average of all vertebral bodies treated within each group.
  • the first data point in Figure 4 for Group I is the average of nine vertebral body measurements (T12, L2, and L4 for each of three animals in Group I) taken after injection of the rhPDGF-BB matrix composition into the vertebral bodies.
  • the first data point in Figure 4 for Group 2 is the average of nine vertebral body measurements (T 12, L2 and L4 for each of three animals in Group II) taken after injection of a collagen/B-TCP matrix into the vertebral bodies.
  • vBMD continued to increase through the sixth month of the study before reaching a plateau at the ninth month.
  • Vertebral bodies treated with a composition comprising 20 mM sodium acetate buffer disposed in the ⁇ -TCP/collagen matrix did not demonstrate significant increases in vBMD over the course of the study.
  • Figure 5 illustrates percent change in vBMD for vertebral bodies of animals of Group I and Group II wherein the injected ⁇ -TCP/collagen matrix is subtracted from the volumetric bone mineral density analysis.
  • each data point in Figure 5 represents an average of all vertebral bodies treated within each group.
  • vertebral bodies treated with a rhPDGF-BB matrix composition demonstrated increases in vBMD.
  • the subtraction of the ⁇ -TCP/collagen matrix from the volumetric bone mineral density analysis provided a clear indication that vBMD increased throughout all regions of the vertebral bodies of Group I as opposed to regions local to the injection site of the rhPDGF-BB matrix composition.

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Abstract

La présente invention concerne des compositions et des procédés utiles pour le traitement de structures de la colonne vertébrale, y compris les corps vertébraux. Dans un mode de réalisation, l'invention a pour objet un procédé pour favoriser la formation osseuse dans un corps vertébral en fournissant une composition qui renferme une solution de PDGF et une matrice biocompatible et en appliquant la composition sur au moins un corps vertébral. Favoriser la formation osseuse dans un corps vertébral, selon certains modes de réalisation, peut augmenter le volume, la masse et/ou la densité de l'os menant à une augmentation de la force mécanique du corps vertébral traité avec une composition de la présente invention.
PCT/US2008/065666 2006-06-30 2008-06-03 Compositions et procédés de traitement de la colonne vertébrale WO2008151193A1 (fr)

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CA2689986A CA2689986C (fr) 2007-06-04 2008-06-03 Compositions et procedes de traitement de la colonne vertebrale
CN200880101796A CN101820895A (zh) 2007-06-04 2008-06-03 用于治疗脊柱的组合物和方法
AU2008259785A AU2008259785B2 (en) 2007-06-04 2008-06-03 Compositions and methods for treating the vertebral column
US12/631,731 US9161967B2 (en) 2006-06-30 2009-12-04 Compositions and methods for treating the vertebral column
US14/853,901 US11058801B2 (en) 2006-06-30 2015-09-14 Compositions and methods for treating the vertebral column
US17/373,330 US20220105246A1 (en) 2006-06-30 2021-07-12 Compositions and methods for treating the vertebral column

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US7943573B2 (en) 2008-02-07 2011-05-17 Biomimetic Therapeutics, Inc. Methods for treatment of distraction osteogenesis using PDGF
US8106008B2 (en) 2006-11-03 2012-01-31 Biomimetic Therapeutics, Inc. Compositions and methods for arthrodetic procedures
US8114841B2 (en) 2004-10-14 2012-02-14 Biomimetic Therapeutics, Inc. Maxillofacial bone augmentation using rhPDGF-BB and a biocompatible matrix
JP2013545584A (ja) * 2010-12-13 2013-12-26 バイオミメティック セラピューティクス，リミテッド ライアビリティ カンパニー 脊椎固定術用の組成物および方法
US9161967B2 (en) 2006-06-30 2015-10-20 Biomimetic Therapeutics, Llc Compositions and methods for treating the vertebral column
US9545377B2 (en) 2004-10-14 2017-01-17 Biomimetic Therapeutics, Llc Platelet-derived growth factor compositions and methods of use thereof
US9642891B2 (en) 2006-06-30 2017-05-09 Biomimetic Therapeutics, Llc Compositions and methods for treating rotator cuff injuries
US10071182B2 (en) 2014-10-14 2018-09-11 Samuel E. Lynch Methods for treating wounds
US10258566B2 (en) 2004-10-14 2019-04-16 Biomimetic Therapeutics, Llc Compositions and methods for treating bone

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WO2004071543A1 (fr) * 2003-02-13 2004-08-26 Synthes Ag Chur Melange injectable de remplacement d'os
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Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10258566B2 (en) 2004-10-14 2019-04-16 Biomimetic Therapeutics, Llc Compositions and methods for treating bone
US9545377B2 (en) 2004-10-14 2017-01-17 Biomimetic Therapeutics, Llc Platelet-derived growth factor compositions and methods of use thereof
US8114841B2 (en) 2004-10-14 2012-02-14 Biomimetic Therapeutics, Inc. Maxillofacial bone augmentation using rhPDGF-BB and a biocompatible matrix
US11571497B2 (en) 2004-10-14 2023-02-07 Biomimetic Therapeutics, Llc Platelet-derived growth factor compositions and methods of use thereof
US11364325B2 (en) 2004-10-14 2022-06-21 Biomimetic Therapeutics, Llc Platelet-derived growth factor compositions and methods of use thereof
US11318230B2 (en) 2004-10-14 2022-05-03 Biomimetic Therapeutics, Llc Platelet-derived growth factor compositions and methods of use thereof
US10456450B2 (en) 2006-06-30 2019-10-29 Biomimetic Therapeutics, Llc Compositions and methods for treating rotator cuff injuries
US9642891B2 (en) 2006-06-30 2017-05-09 Biomimetic Therapeutics, Llc Compositions and methods for treating rotator cuff injuries
US9161967B2 (en) 2006-06-30 2015-10-20 Biomimetic Therapeutics, Llc Compositions and methods for treating the vertebral column
US11058801B2 (en) 2006-06-30 2021-07-13 Biomimetic Therapeutics, Llc Compositions and methods for treating the vertebral column
US8106008B2 (en) 2006-11-03 2012-01-31 Biomimetic Therapeutics, Inc. Compositions and methods for arthrodetic procedures
US8399409B2 (en) 2006-11-03 2013-03-19 Biomimetic Therapeutics Inc. Compositions and methods for arthrodetic procedures
US7943573B2 (en) 2008-02-07 2011-05-17 Biomimetic Therapeutics, Inc. Methods for treatment of distraction osteogenesis using PDGF
US8349796B2 (en) 2008-02-07 2013-01-08 Biomimetic Therapeutics Inc. Methods for treatment of distraction osteogenesis using PDGF
EP2651319A4 (fr) * 2010-12-13 2016-08-17 Biomimetic Therapeutics Llc Compositions et méthodes pour des interventions de type fusion spinale
JP2017018710A (ja) * 2010-12-13 2017-01-26 バイオミメティック セラピューティクス，リミテッド ライアビリティ カンパニー 脊椎固定術用の組成物および方法
JP2013545584A (ja) * 2010-12-13 2013-12-26 バイオミメティック セラピューティクス，リミテッド ライアビリティ カンパニー 脊椎固定術用の組成物および方法
US10071182B2 (en) 2014-10-14 2018-09-11 Samuel E. Lynch Methods for treating wounds

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