Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Implant or insert
Reexamination Certificate
2002-03-14
2003-07-29
Azpuru, Carlos A. (Department: 1615)
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Implant or insert
Reexamination Certificate
active
06599520
ABSTRACT:
BACKGROUND OF INVENTION
This invention relates to methods for the treatment of porous bone, e.g., osteoporotic bone. The expression “porous bone” is intended herein to identify a condition of porosity and/or decreased bone mineral density that distinguishes the morphology of bone exhibiting a pathological condition from healthy bone. A common type of porous bone pathology is osteoporosis.
Osteoporosis is a pathologic state or disease involving some symptom or risk due to quantitative bone reduction exceeding a certain degree. Major symptoms are spinal kyphosis, fractures of dorsolumbar bones, vertebral centra, femoral necks, lower ends of radius, ribs, upper end of humerus, and others. In normal bone tissue, bone breakdown occurs constantly, but there is good balance between formation and resorption; osteoblasts and osteoclasts play key roles in bone formation and bone resorption, respectively. Upon deterioration of this balance, bone resorption surpasses bone formation, resulting in quantitative bone reduction.
Osteoporosis results in bone fractures in about 50% of postmenopausal women and is a leading cause of disability in an aging population. The decrease in bone mineral density and changes in architecture that accompany postmenopausal osteoporosis predisposes elderly women to fractures, particularly of the vertebral bodies. It is not elderly persons alone who suffer from this painful condition. Other individuals, such as transplant recipients, suffer fractures as a result of chronic steroid use. Current therapies include an adequate calcium and vitamin D intake as well as specific treatment with compounds such as estrogens, calcitonin and the bisphosphonates. However, each of these treatments has either troubling side effects or limited efficacy. Women fear the small increase in potential risk of breast cancer due to estrogens despite the dramatic reduction in myocardial infarctions and reduction in bone resorption. Calcitonin has a limited effect and is a protein and therefore needs to be injected or inhaled which is inconvenient. The new bisphosphonates such as alendronate have had encouraging results with an increase in bone density and decrease in fractures, however, some upper gastrointestinal irritation has been reported (Abraham et al., 1999, Mod. Pathol. Dec 12(12): 1152-1157). Current research for new compounds has concentrated on the systemic administration of bone anabolic compounds such as parathyroid hormone (PTH) or fragments of PTH or locally acting cytokines or bone growth factors such as bone morphogenic proteins. When these therapies are unable to prevent fractures of porous bone, the victims of such fractures suffer from persistent, often excruciating pain, which significantly impairs mobility and quality of life. External bracing, analgesics, and observation may be all that is necessary for pain control in some patients, but in others, a constant requirement for narcotics can be as life altering as the fracture itself.
Vertebroplasty has been described in the literature as a method of injecting materials into vertebral bodies via a pedicle approach. Patients with various problems including osteoporosis, tumor or trauma have deficiencies of the vertebral body leading to pain or other complications. By injecting methylmethacrylate (bone cement) into these areas interventional radiologists or other physicians are able to avoid further subsidence of the vertebrae and alleviate pain. This procedure can be done on an outpatient basis, but currently is reserved for patients with major problems. The current methods of vertebroplasty are directed toward treatment once a fracture occurs. Therefore, a prophylactic treatment directed toward reducing the tendency for porous vertebrae to fracture would be highly desirable
This invention describes the use of a flowable bone graft composition to induce bone growth at porous bone sites. A suitable bone graft for this indication would have the properties of flowability. i.e., allowing for injection through a 2-6 mm or larger trocar, and ability to support formation of new bone at the porous bone site. An ideal material would be flowable DBM (with or without enhancing substances such as BMP) such as that disclosed in U.S. Pat. Nos. 5,073,373, 5,236,456, 5,314,476, 5,405,390, 5,484,601 and 5,510,396 and commonly assigned PCT/US00/28462, filed Oct. 13, 2000, the contents of all of which are incorporated herein by reference.
BRIEF SUMMARY OF THE INVENTION
It is an object of the invention to provide a method of treating a vertebrate animal having increased bone porosity and/or decreased bone mineral density.
It is a further object of the invention to provide a method for treating osteoporotic patients at risk for fracture of the vertebra or other sites.
It is a further object of the invention to provide a method for increasing the bone mineral density and/or decreasing bone porosity thereby decreasing the risk for future fracture.
It is a further object of the invention to provide a method of treating at risk vertebrae adjacent to a fractured vertebra.
The stated objects of the invention are not intended to be limiting in any way. Of course, further objects of the invention herein will be obvious to those skilled in the art in view of the above stated objects and the foregoing specification.
In keeping with these and related objects of the invention, there is provided a method of treating a condition in a vertebrate animal, the condition characterized by bone having increased porosity and/or decreased bone mineral density, which comprises injecting the porous bone with an effective amount of a flowable bone composition. The foregoing method applied to a site of increased bone porosity and/or decreased bone mineral density, e.g., one resulting from disease, malignancy or developmental malformation, leads to rapid new bone ingrowth by one or more mechanisms such as osteogenesis, osteoconduction and osteoinduction. The method of this invention is relatively simple, e.g., it can be performed on an outpatient basis, and relatively inexpensive, and avoids the major complications caused by vertebral fracture.
DETAILED DESCRIPTION OF THE INVENTION
The method described herein is performed on individuals identified as being at risk for bone fracture due to increased bone porosity and/or decreased bone mineral density. Such individuals are identified using methods well known in the art, e.g., bone density scans, radiographic imaging, medical history. The conditions leading to decrease in bone density can include, e.g., osteoporosis, osteomalacia, osteotis fibrosa, Paget's disease, bone deficiency, primary or secondary hyperparathyroidism, chronic inflammatory conditions, metastatic bone disease and osteolytic bone disease. When the condition is osteoporosis, the osteoporosis can be due to a number of conditions, e.g., age-related osteoporosis, post-menopausal osteoporosis, juvenile osteoporosis, Cushing's syndrome osteoporosis, multiple myeloma osteoporosis, leukemia osteoporosis, Turner's syndrome osteoporosis, alcohol osteoporosis, chronic liver disease osteoporosis, glucocorticoid-induced osteoporosis, chronic inflammatory disease induced osteoporosis and disuse osteoporosis. The site of decreased bone density can be trabecular bone, cortical bone, etc. When the bone site is trabecular bone the bone can include, e.g., vertebrae, rib, clavicle, sternum, femoral neck, hip, wrist and the distal ends of the long bones.
Once the site of decreased bone density is located utilizing methods well known in the art, e.g., bone density scans, radiographic imaging, medical history, a suitable amount of a flowable bone composition is injected into the bone site utilizing methods well known in the art, e.g., through a needle or cannula, e.g., a Jamshidi®11 gauge bone marrow biopsy/aspiration needle. In a preferred embodiment of the invention, a percutaneous vertebroplasty technique as described by Jensen et al.
Diagnostic Imaging
, pp. 68-72, September 1997, the contents of which are incorporated herein by reference, is used to in
Russell James
Scarborough Nelson L.
Azpuru Carlos A.
Dilworth & Barrese LLP
Osteotech Inc.
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