Composition used in the treatment of herniated discs

Abstract

The present invention relates to a composition for use in the treatment of a herniated disc, said composition comprising lactic acid, said composition being administered to a disc space containing NPs of a herniated disc.

Description

Technical Field

[0001] The present invention relates to a composition for treating intervertebral disc herniation.

Background Art

[0002] Low back pain is thought to affect over 80% of people at some point in their lives and is one of the most prevalent medical conditions worldwide. Low back pain is not a specific disease with known pathophysiology, but rather a symptom caused by many factors. Low back pain is the main cause of disability in humans under 40 years old. The lifetime prevalence of low back pain is about 70 - 85%, and about 10 - 20% experience chronic low back pain, which basically imposes a significant burden on the medical, social, and economic aspects of all countries.

[0003] Many patients suffering from chronic lower back pain have a condition known as a herniated disc, or symptomatic bulging or herniated disc (IVD). The intervertebral disc is located between two adjacent vertebrae. Normally flexible, it allows movement between adjacent vertebrae. It is formed by a disc-shaped outer portion of connective tissue, primarily collagen, and a semi-liquid central portion containing, for example, collagen and proteoglycans. The outer portion is called the annulus fibrosus (AF), and the central portion is called the nucleus pulposus (NP). The NP is highly gelatinous, composed of 70-90% water, 25-60% proteoglycans (dry weight), and 10-20% collagen (dry weight). The function of the NP is to withstand prolonged compression during the day and to elastically re-expand at night, restoring the disc's height. The NP is held and surrounded by a cartilaginous AF layer. Together, the NP and AF act as an elastic cushion. In an upright posture, body weight constantly compresses the stack of cushions arranged alternately between a series of vertebrae. During this constant compression, the NPs in each intervertebral disc also function as reservoirs, slowly and constantly being squeezed and draining water through the endplates connected to the vertebrae. As a result, the height of the intervertebral discs decreases slightly during the day. During bed rest, the body does not compress the intervertebral discs. Therefore, due to the water absorption of the NPs, the water flows back from the vertebral vessels to the proteoglycan and collagen matrix. As a result, the height of the intervertebral discs is restored, ready to provide support and flexibility the following day.

[0004] A herniated disc can be defined as a deformation of the disc nucleus. Depending on the type and characteristics of the deformation, a herniated disc can be defined as disc bulging, disc protrusion, disc extrusion, or disc freeing. In the case of protrusion, the nucleus is located inside the outer annular fibers, but this is not the case in the case of extrusion. The latter is characterized by the neck of the herniation being narrower than the fornix, while in protrusion, its shape is closer to a triangle. Disc extrusion is often followed by freeing, where the freed disc material is found within the spinal canal. Extrusion can be treated with intradiscal injection, but freeing requires surgical removal.

[0005] Most herniated discs occur in people between the ages of 30 and 50, but they can also occur in teenagers and older adults. Approximately 30% of people in Western countries will experience sciatica, primarily due to a herniated disc, at some point in their lives. In Sweden, up to 2% of the population will undergo surgery for a herniated disc during their lifetime. Herniated discs primarily occur in the lower back, specifically in the intervertebral discs between the lumbar vertebrae L1 and L5. This type of IVD herniation is called a lumbar disc herniation (LDH). The two lowest lumbar discs account for 95% of all LDH cases. However, herniations can occur in other areas of the spine as well.

[0006] The annual incidence rate is 0.5–2% of all adults, and this disease is twice as common in men as in women. The prevalence rate fluctuates between 1% and 3%.

[0007] Many herniated discs resolve spontaneously and are therefore left untreated. First-line treatment is non-surgical, encompassing both pharmacological and non-pharmacological therapies. NSAIDs are the most commonly used drugs, but opioids are also frequently used. The use of antispasmodics, such as baclofen, is part of pharmacological treatment, and gabapentin and tricyclic antidepressants are also used occasionally, although their effectiveness is uncertain. Epidural steroid injections have been found to be effective for herniated discs. For a long time, physical therapy was considered effective, but recent data do not support this. Other non-pharmacological treatments include acupuncture and physical therapy, but the evidence for their effectiveness is weak.

[0008] Other treatment options are minimally invasive and include chemopulposus lysis or percutaneous nucleotomy.

[0009] In chemonucleolysis, enzymes, ethanol, or ozone / oxygen are injected into the intervertebral disc to dissolve NPs, thereby reducing the pressure that NPs exert on, for example, the spinal nerves. For this purpose, intradiscal injection of chymopapain was widely used until the turn of the year 2000. This treatment has proven effective, and its mechanism of action is the enzymatic degradation of the extracellular matrix, which reduces the volume of the intervertebral disc. Serious side effects, such as paraplegia (impairment of sensory and motor function in the lower extremities) and, in some cases, anaphylactic reactions which can be fatal, led to the subsequent withdrawal of the product from the market. Another drawback of chemonucleolysis is that the height of the treated intervertebral disc may become too small, leading to disc degeneration and subsequent back pain. Other enzymes, such as chondriase, have been tested / are under development, but they also have the potential to cause various serious side effects. Stem cells and platelet-rich plasma have also been evaluated and shown some promise, but there are few controlled trials to demonstrate their effectiveness.

[0010] An alternative to chemical nucleolysis is percutaneous nucleotomy, in which NPs are partially removed mechanically or by vacuum to reduce the volume of the IVD. However, the amount of NP removed cannot be precisely controlled, leading to unpredictable results and a low success rate.

[0011] Surgery (discectomy) is the gold standard for second-line treatment of herniated discs. Discectomy is very effective for symptoms, especially radiating pain in the lower extremities. Approximately 85% of patients who undergo surgery for a herniated disc are satisfied with the results. Nevertheless, discectomy carries a 15-25% risk of reoperation.

[0012] Numerous postoperative complications can occur after back surgery. The main ones are lumbar scarring and spinal instability. If scar tissue spreads and invades the laminectomy site and intervertebral foramina, it can lead to recurrent pain and subsequent surgery. In fact, reoperations are very common, reaching 10-20%. Unfortunately, the success rate of reoperations is often lower than that of the initial surgery, and in some cases, much lower. Reoperations lead to further scarring and resulting pain. Currently, it is recommended to avoid surgical intervention unless the pain and discomfort are completely unbearable. Even if the surgery is successful and long-term pain is reduced, isokinetic tests clearly show weakness compared to people who have not undergone surgery.

[0013] In consideration of these drawbacks, various minimally invasive surgical treatments for herniated discs have been developed. One such method is the introduction of various devices, such as those disclosed in U.S. Patent No. 5,800,550, International Publication No. 00 / 40159, International Publication No. 01 / 95818, and U.S. Patent Application Publication No. 2004 / 097927, which are designed to reinforce the intervertebral disc space and fix it in or near the IVD. However, such devices have the disadvantage of reducing the elastic cushioning, rotation, or mobility of the vertebrae and can lead to various postoperative complications.

[0014] Despite extensive research in the field that provides numerous methods for treating herniated discs, there remains a need for minimally invasive methods that are simple, have minimal or no side effects, and provide long-term efficacy. [Overview of the project]

[0015] The present invention aims to solve at least some of the problems of the prior art. To this end, the present invention provides a composition for use in the treatment of a herniated disc, the composition comprising lactic acid, which is administered into the intervertebral disc cavity containing NP of a herniated intervertebral disc.

[0016] In this application, the term "treatment" means the elimination of the causes and symptoms of a herniated disc, as well as the prevention of recurrence.

[0017] In this invention, the term "intervertebral disc" (IVD) refers to the element located between two adjacent vertebrae in the spine. Each intervertebral disc forms a cartilaginous joint that allows slight movement of the vertebrae and acts as a ligament to hold the vertebrae in place. An intervertebral disc consists of an outer AF surrounding an inner NP. The human spine contains 23 intervertebral discs: 6 in the neck (cervical region), 12 in the mid-back (thoracic region), and 5 in the lower back (lumbar region). In addition, intervertebral discs are also located between the coccyx. An intervertebral disc can also be called a disc.

[0018] The term "NP" refers to the jelly-like substance in the center of the intervertebral disc. NP contains chondrocyte-like cells, collagen fibrils, and aggrecan, a proteoglycan that aggregates via hyaluronic acid chains. Binding each aggrecan molecule are glycosaminoglycan (GAG) chains of chondroitin sulfate and keratan sulfate. NP acts as a shock absorber, keeping two adjacent vertebrae separated.

[0019] The term "AF" refers to the fibrous tissue and fibrocartilage layer (lamina) that forms around the periphery of the NP. The AF plays a role in evenly distributing pressure throughout the intervertebral disc.

[0020] The term "intervertebral disc space" refers to the space within the intervertebral disc that is filled by NPs and has an outer circumference defined by AFs.

[0021] The term "cranial endplate" refers to the surface of the intervertebral disc facing the skull. The cranial endplate is located on the opposite side of the intervertebral disc from the caudal endplate.

[0022] The term "caudal endplate" refers to the surface of the intervertebral disc facing the opposite side of the skull. The caudal endplate is located on the opposite side of the intervertebral disc from the cranial endplate.

[0023] The term "facet joint" (also known as the zygapophyseal joint) generally refers to a paired joint structure having joint surfaces covered with articular cartilage. The facet joints are typically enclosed by a capsule. The facet joints form a joint between the inferior articular processes of a vertebra and the superior articular processes of a vertebra. The facet joints are typically constructed to allow movement and provide mechanical support to the spinal column.

[0024] The term "transverse process" means a bony formation extending laterally from the vertebral arches on both sides. This is also called the costal process.

[0025] In this specification, the term "intervertebral disc herniation" means a deformation of the IVD such that the normal shape of the IVD changes. The intervertebral disc herniation may be a nuclear herniation (intervertebral disc bulge), an intervertebral disc protrusion, an intervertebral disc extrusion or a sequestration.

[0026] In this specification, the term "flexural rigidity" means a property representing the rigidity of an intervertebral disc disposed in a segment of the spinal column. The flexural rigidity can be determined by applying a force to a segment of the spinal column until it reaches a full lateral bending mode, and then measuring the distance between the transverse processes of two vertebrae opposing each other at the intervertebral disc. The full lateral bending mode is defined as a state where the intervertebral disc of the segment of the spinal column cannot be further pushed forward without breaking the segment of the spinal column. The unit of this property is millimeters. The flexural rigidity is a characteristic of the bending rigidity of a segment of the spinal column, more specifically, the bending rigidity of the intervertebral disc.

[0027] Bending rigidity is generally defined as the couple required to bend a non-rigid structure to a unit curvature. This is a measure of the rigidity of a structural member; it is the product of the modulus of elasticity and the moment of inertia divided by the length of the member. In other words, it is the ratio of stress to strain in the material when the elastic material is being bent.

[0028] The concept of the present invention is to provide a composition for treating IVD hernia in two steps. In the first step, the intervertebral disc in the hernia state is dehydrated by histological changes characterized by the melting of the extracellular matrix, and the volume of the intervertebral disc and the height of the intervertebral disc are reduced. The reduction in volume is accompanied by a decrease in pressure, which leads to a reduction in intervertebral disc deformation. Therefore, the protruding part of the intervertebral disc is minimized or eliminated, the pressure on the nerve surrounding the intervertebral disc is reduced, and the pain is alleviated. In the second step, the intervertebral disc in the hernia state treated with the composition of the present invention has accelerated tissue remodeling, thereby making the intervertebral disc rigid, for example, by conversion to a firm and dense connective tissue of the intervertebral disc. The conversion of the intervertebral disc to a firm and dense connective tissue stabilizes the intervertebral disc, and as a result, the risk of hernia recurrence is minimized. Furthermore, the intervertebral disc converted to a firm and dense connective tissue does not allow the fluid component that stimulates the nerve to leak out from the intervertebral disc cavity, for example, to the outer surface of the AF or to the spinal nerve root. Since the pain associated with intervertebral disc hernia is considered to result from a combination of nerve compression and leakage of compounds that stimulate the nerve, the factors causing these symptoms are reduced or eliminated by the treatment of IVD with the composition of the present invention.

[0029] The inventors have surprisingly found that lactic acid seems to succeed in treating intervertebral disc hernia. This finding is particularly surprising considering the prior art that has rather focused on reducing the amount of lactic acid in the intervertebral disc that causes pain. For example, US Patent Application No. 2012 / 0022425 discloses a method of reducing lactic acid in the intervertebral disc by injecting a lactic dehydrogenase inhibitor into the vertebral lamina to inhibit the production of lactic acid, thereby alleviating back pain caused by lactic acid stimulation. Furthermore, International Publication No. 2013 / 092753 discloses indole derivatives for inhibiting the production of lactic acid, for example, in the treatment of chronic back pain.

[0030] For example, considering International Publication 2015 / 140320, which describes the use of lactic acid or a pharmaceutically acceptable salt thereof to accelerate disc aging and reduce disc-related pain by making the disc rigid by converting it into firm, dense connective tissue, the intuitive conclusion is that the use of lactic acid in the treatment of herniated discs is contraindicated because the formation of connective tissue within the hernia makes it impossible to shrink the hernia and may make the hernia permanent. However, the inventors have surprisingly found that lactic acid is very suitable for use in the treatment of herniated discs and the prevention of re-herniation due to its stepwise and dual action, in which histological changes characterized by the thawing of the extracellular matrix accompanied by dehydration occur first, the deformation is corrected, and then the nuclear tissue is altered into a fibrous structure, making the intervertebral disc rigid and stable and preventing recurrence.

[0031] Lactic acid has the following chemical structure: [ka] It is a carboxylic acid having [a certain characteristic].

[0032] As seen in formula (I), lactic acid has a chiral center at C-2. Therefore, the two enantiomers of lactic acid are (S)-lactic acid (also known as L-(+)-lactic acid) and its mirror image is (R)-lactic acid (also known as D-(-)-lactic acid). An equimolar mixture of the two enantiomers is called DL-lactic acid or racemic lactic acid. In this invention, the term "lactic acid" means either of the above enantiomers or a mixture thereof. In other words, in this invention, "lactic acid" may be in an enantiomerally pure form or a racemic mixture.

[0033] Lactic acid may undergo deprotonation in aqueous solution, that is, it loses a proton from its carboxyl group to form the lactate ion CH3CH(OH)COO - It may be produced. The mole fraction of lactic acid and lactate ions is 1:1.

[0034] CH3CH(OH)COOH (aqueous solution) → CH3CH(OH)COO - +H + (I) Lactic acid and lactates are naturally present in the human body.

[0035] The concentration of lactate ions in the tissue fluid of IVDs in herniated patients has been measured to be between 1 mmol / L and approximately 12 mmol / L, and typically between 2 mmol / L and 6 mmol / L.

[0036] As shown in Table 1, the molecular weight of lactate ions is 89.07 g / mol. Therefore, the molar concentration of 1 mmol of lactate ions per liter of tissue fluid in the intervertebral disc corresponds to a mass concentration of 89.07 mg / L. Similarly, the molar concentration of 12 mmol of lactate ions per liter of tissue fluid in the intervertebral disc corresponds to a mass concentration of 1067 mg / L.

[0037] In humans, the volume of the intervertebral disc space in the lumbar intervertebral disc is estimated to be approximately 1.5 ml to 3.0 ml.

[0038] Considering the above, a person skilled in the art can easily calculate the amount of lactic acid in the intervertebral disc, expressed in moles or grams. An example is shown in Table 1.

[0039] [Table 1]

[0040] Naturally occurring lactic acid or lactate ions may adversely affect the function of intervertebral disc cells, particularly those that produce proteoglycans necessary to prevent disc aging. Disc aging begins primarily with a reduction in the supply of nutrients and oxygen due to diffusion from blood vessels in the adjacent endplate. This gradually induces the accumulation of metabolic waste products in the intervertebral disc, e.g., NP. One type of metabolic waste product that may be present is lactic acid or lactate. Lactic acid may contribute to several mechanisms that lead to cell death in the intervertebral disc.

[0041] Lactic acid triggers events that lead to the breakdown of large water-binding molecules, such as GAGs. Simultaneously, lactic acid stimulates the release of TGFβ, which in turn stimulates fibroblasts to produce collagen. This loss of water retention capacity (dehydration) of NP is followed by a reduction in volume.

[0042] Lactic acid may further release PGE2, leading to the formation of connective tissue that increases the rigidity of the intervertebral disc, which can be described as accelerated IVD aging.

[0043] Therefore, the administration of a lactic acid-containing composition into the intervertebral disc space increases the concentration of lactic acid in the intervertebral disc, which has a dual, stepwise effect on IVD. Histological changes characterized by the thawing of the extracellular matrix lead to dehydration of IVD, reducing the height, volume, and pressure of the intervertebral disc, followed by the conversion of NP into connective tissue.

[0044] As described above, the dehydration of the herniated IVD caused by the composition of the present invention reduces the volume of the herniated IVD, which reduces deformation and protrusion or extrusion of the herniated IVD. Facilitating subsequent controlled remodeling of the intervertebral disc, including the conversion of NP to connective tissue, makes the intervertebral disc rigid, thereby preventing recurrence of the herniated disc.

[0045] Normally, lactic acid levels can increase in herniated intervertebral discs, specifically in the intervertebral disc space, to dehydrate the IVD and subsequently promote fibrosis.

[0046] The inventors have found that a lactic acid-containing composition induces histological changes characterized by the thawing of the extracellular matrix, dehydrating the herniated intravertebral disc (IVD), causing a decrease in its volume and a significant conversion of the intervertebral disc to connective tissue, thereby making it rigid. The volume reduction reduces the height of the IVD, thus eliminating or minimizing the hernia. This significant conversion is interpreted as accelerated aging of the intervertebral disc due to the conversion of the NP to connective tissue. As a result, improvement in patients with intervertebral disc herniation is achieved when a lactic acid-containing composition is administered to the NP of the herniated intervertebral disc, increasing the concentration of lactic acid in the intervertebral disc cavity.

[0047] The advantages of the composition used for treating intervertebral disc herniation according to the present invention are that it is a safe and more efficient treatment of intervertebral disc herniation, and furthermore, it is less expensive and less invasive than most treatments known in the art. In addition, lactic acid is biocompatible. Since this compound is naturally present in the bodies of vertebrates, the bodies of vertebrates, such as humans, can process, for example, lactic acid.

[0048] The inventors suggest that when the composition used for treating intervertebral disc herniation according to the present invention is administered to the NP, a dual, stepwise effect is obtained, as described above. First, histological changes begin, characterized by the thawing of the extracellular matrix, at least partially dissolving the NP. Since the extracellular matrix is ​​composed of molecules that provide high osmotic pressure, the IVD is dehydrated, which reduces the volume and height of the IVD. This causes a pressure drop that is transmitted to the herniation. As a result, the herniation contracts, alleviating symptoms such as pain and limited range of motion. Finally, the NP in the intervertebral disc is transformed into firm, dense connective tissue, similar to the connective tissue of the AF. The increased rigidity is expected to result in the prevention of recurrence of intervertebral disc herniation and stabilization of the kinetic segment.

[0049] The composition used in the present invention may be administered in an amount effective to increase the concentration of lactate in the intervertebral disc space of a herniated IVD to a concentration higher than that of natural aging. The composition of the present invention is administered in an amount effective to increase the concentration of lactate in the intervertebral disc space to at least 20 mmol / L. The concentration of lactate in the intervertebral disc space after administration of the composition of the present invention may be 20-25 mmol / L. Furthermore, the concentration of lactate in the intervertebral disc space after administration of the composition of the present invention should be less than 1.3 mol / L.

[0050] The composition of the present invention may be administered in an amount effective in dehydrating a herniated disc. In this specification, the term “dehydrate” means reducing the water content in the NP. The water content may be reduced from 90% to 70%. As previously stated, dehydration of the NP may be accompanied by a reduction in the volume of the IVD. It should be noted that the reduction in IVD height in the experiments described later was similar to the results obtained during chemonucleolysis using chymopapain or chondriase. Typically, the disc height decreases by 5-20%, preferably 10-15%, as a result of administration of the composition of the present invention. It should be noted that the reduction in disc height due to natural aging, associated with symptoms such as pain and limited range of motion, is usually much higher, for example, 30-50%. Therefore, a controlled and limited reduction in disc height caused by the composition of the present invention, accompanied by the conversion of the NP of the disc to firm, dense connective tissue, is beneficial in the treatment of herniated discs. The composition of the present invention moderately reduces the height of the intervertebral disc, alleviating the discomfort and pain of a herniated disc without subsequently developing back pain.

[0051] Therefore, the composition of the present invention may be administered in an amount effective in reducing the height of the herniated intervertebral disc and initiating fibrosis of the herniated intervertebral disc.

[0052] The composition of the present invention may have a lactic acid concentration of at least 12 mmol / L, preferably 50 to 12,000 mmol / L, more preferably 100 to 10,000 mmol / L, even more preferably 500 to 5,000 mmol / L, and most preferably 800 to 2,000 mmol / L.

[0053] The composition of the present invention may be administered by local injection into the intervertebral disc space containing the NP of a herniated IVD. Local injection may usually be performed using a syringe under local or general anesthesia, or under local anesthesia combined with sedation.

[0054] According to one embodiment, the amount of lactic acid in a single-dose composition is 2 mg to 1000 mg, for example, 5 mg to 500 mg, preferably 10 to 300 mg, more preferably 20 to 200 mg, and more preferably 90 to 180 mg. The single dose corresponds to the amount of lactic acid administered per intervertebral disc space.

[0055] The composition of the present invention may be administered on a single occasion, or in a single dose on repeated occasions.

[0056] In this specification, the term "single occasion" means a single visit to a healthcare facility, such as visiting a doctor at a hospital. This visit may be within 24 hours, for example, 0.5 to 5 hours. This term usually means that a single dose is administered only once on a single occasion, but is not necessarily so. This term also covers cases where a single dose is administered multiple times on a single occasion, for example, 2 to 10 times on a single occasion, or 2 to 5 times on a single occasion.

[0057] In this specification, the term “repeated occasion” means two or more visits to a medical institution, i.e., multiple visits, such as visiting a doctor at a hospital two or more times. Each of these visits may be within 24 hours, for example, 0.5 to 5 hours. The term usually means that a single dose is infused only once per repeated occasion, but is not necessarily so. The term also covers cases where a single dose is infused multiple times in a repeated occasion, for example, 2 to 10 times in each of the repeated occasions, for example, 2 to 5 times in each of the repeated occasions.

[0058] The composition of the present invention may be an aqueous solution containing lactic acid at the above concentration.

[0059] The pH of the composition of the present invention may be less than 4.0, preferably less than 3.5, and more preferably less than 3.0. A low pH is beneficial because IVD has a buffering effect, which may counteract the mechanism of the composition of the present invention.

[0060] Compositions used to treat herniated discs are typically provided in formulations suitable for local injection in therapeutically effective doses.

[0061] The composition of the present invention may further contain a contrast agent. The contrast agent may be an iodine-containing contrast agent, such as Visipaque®, Omnipaque® (iohexol), etc. The contrast agent may be required for fluoroscopic guidance to confirm the correct placement of the needle during injection and for post-treatment radiological examinations, such as computed tomography (CT). Post-treatment radiological examinations may be performed to ensure that no leakage of the composition administered to the IVD occurs.

[0062] In this invention, intervertebral disc herniation is selected from nuclear herniation (disc bulging), intervertebral disc protrusion, or intervertebral disc extrusion.

[0063] In some examples, the composition may further contain at least one agent selected from solubilizers, stabilizers, buffers, isotonic agents, bulking agents, thickeners, viscosity reducers, surfactants, chelating agents, preservatives, and adjuvants.

[0064] In another example, a derivative of lactic acid, such as ethyl lactate or a polymer of lactic acid, may be administered additionally or as a prodrug.

[0065] In humans, the amount of composition administered may be 0.05 mL to 5 mL, for example, 0.1 to 3 mL, or for example, 0.2 mL to 2 mL. These amounts more or less correspond to the volume of NP in humans. For lumbar intervertebral discs, the amount of composition administered may be about 1.5 mL to 3.0 mL. For cervical intervertebral discs, the amount of composition administered may be about 0.5 mL. For coccygeal intervertebral discs, the amount of composition administered may be about 0.2 mL.

[0066] According to the second aspect, a method for treating herniated discs is provided, which involves administering a therapeutically effective amount of lactate to the NP of the intervertebral disc of a patient who requires it. The effects and features of this second aspect of the present invention are similar to those described in relation to the first aspect of the present invention.

[0067] According to a third aspect, the use of lactic acid in the manufacture of a pharmaceutical for treating herniated discs is provided. The effects and features of this third aspect of the present invention are similar to those described in the preceding aspects of the present invention.

[0068] According to a fourth aspect, lactic acid for use in the treatment of herniated discs is provided. The effects and features of this fourth aspect of the present invention are similar to those described in the preceding aspects of the present invention.

[0069] Further features and advantages of the present invention will become apparent upon consideration of the claims and the following description. Those skilled in the art will recognize that different features of the present invention may be combined without departing from the scope of the present invention to create embodiments other than those described below.

[0070] These and other aspects of the present invention will be described in further detail in this specification with reference to the drawings illustrating embodiments of the invention. [Brief explanation of the drawing]

[0071] [Figure 1] Figure 1 shows a cross-section of the human spine. [Figure 2] Figure 2 shows a lateral view of two adjacent vertebrae in the human spine. [Figure 3] Figure 3 shows a lateral view of the lower portion of the human spine. [Figure 4] Figure 4 shows an IVD in a herniated state. [Figure 5] Figure 5 shows various types of hernias. [Figure 6] Figure 6 shows the appearance and measurements of porcine NP after treatment with the composition of the present invention. [Figure 7] Figure 7 shows the height of NP. [Figure 8] Figure 8 shows the width of NP. [Figure 9] Figure 9 shows the effects of the composition of the present invention on AF and NP; the appearance and measurements of porcine NP after treatment with the composition of the present invention. [Figure 10] Figure 10 shows the changes in T2-weighted MRI images after treatment with the composition of the present invention. [Figure 11] Figure 11 shows the changes in T2-weighted MRI images after treatment with the composition of the present invention. [Figure 12] Figure 12 shows a T2-weighted MRI image. [Modes for carrying out the invention]

[0072] Detailed description of the present invention The present invention is described below with reference to the drawings illustrating exemplary embodiments of the invention. However, the present invention may be embodied in many different forms and should not be construed as being limited to the embodiments of the invention expressed herein; rather, these embodiments of the invention are provided as examples so that this disclosure conveys the scope of the invention to those skilled in the art. In the drawings, the same reference numerals indicate the same or similar components having the same or similar function unless specifically noted otherwise.

[0073] The vertebral column of vertebrates contains vertebrae, which surround and protect the spinal cord. In humans, the vertebral column is located on the dorsal side of the torso. Intervertebral discs are placed between two adjacent vertebrae; that is, vertebrae and intervertebral discs alternate to form the vertebral column. The specific structure and further parts of the vertebral column are known to those skilled in the art.

[0074] Figure 1 schematically shows a cross-section of a human spine 100. Adjacent to the vertebral body 15 of the vertebra, an intervertebral disc containing AF10 and NP11 is located. NP11 fills the so-called intervertebral disc space. AF10 surrounds NP11 and defines the boundary between NP and the intervertebral disc space.

[0075] The spinal cord 17 is located in the center of the vertebral column and is adjacent to the intervertebral disc. The spinal nerves 16 and 16' extend from the spinal cord 17 to the opposite side of the intervertebral disc, approaching the disc.

[0076] The facet joints 14 and 14' are located between the inferior articular processes 13 and 13' and the superior articular processes 12 and 12'. The two facet joints 14 and 14' are located on the opposite side of the spinal cord 17. The facet joints 14 and 14' are located in approximately the same cross-sectional and planar plane.

[0077] Figure 2 schematically shows a segment of the vertebral column 200 including two adjacent vertebrae 20 and 22. The first vertebra 22 and the second vertebra 20 are located opposite the intervertebral disc 21. The first vertebra 22 is located relatively close to the rib cage, and the second vertebra 20 is located relatively close to the sacrum. The caudal endplate 23 of the first vertebra 22 and the cranial endplate 25 of the second vertebra 20 are shown in Figure 2. The cranial endplate 25 and the caudal endplate 23 face opposite the intervertebral disc 21.

[0078] Figure 2 schematically shows how the facet joint 24 is positioned between the inferior articular process of the first vertebra 22 and the superior articular process of the second vertebra 20. The transverse process 26 extends laterally from the vertebral arch.

[0079] Figure 3 schematically shows the lower part of the vertebral column 300. The coccygeal vertebra 36 of the vertebral column is located at the lower terminal end of the vertebral column 300. The sacrum 39 of the vertebral column is adjacent to the coccygeal vertebra 36 and is located closer to the rib cage than the coccygeal vertebra 36. The fifth lumbar vertebra 30, referred to in this specification as L5, is adjacent to the sacrum 39 and is located closer to the rib cage than the sacrum 39. In the direction from the sacrum 39 toward the rib cage, several vertebrae are arranged in a row, starting from L5, 30. Adjacent to the fifth lumbar vertebra 30, i.e. L5, the following vertebrae are arranged in order: the fourth lumbar vertebra 32, i.e. L4, the third lumbar vertebra, i.e. L3, the second lumbar vertebra, i.e. L2, and the first lumbar vertebra 38, i.e. L1; the first lumbar vertebra is located relatively closest to the rib cage. Between each pair of adjacent vertebrae, an intermediate intervertebral disc 31 is located. The intervertebral disc (not shown) also presses against the coccygeal vertebra 36.

[0080] Figure 4 shows an example of an IVD in a herniated state. Thus, during a herniation, the IVD deforms, allowing AF10 to rupture or weaken, and NP11 to protrude laterally from its normal boundary. This protrusion can compress spinal nerves, causing pain and limited range of motion. Figure 5 shows various types of intervertebral disc herniation. [Examples]

[0081] Example 1 Three series of in vivo experiments were conducted. While the focus of each series differed slightly, the methods were the same unless otherwise noted. Measurements did not completely overlap due to differing objectives, but the most important endpoint, NP curing, was measured using the same method in all studies. Therefore, merging data from different series was considered justifiable.

[0082] Where necessary, Student's unpaired two-sided t-test was used to compare the effect of LA with placebo treatment. The null hypothesis (no difference between LA and placebo) was rejected with p<0.05. The correlation between NP sizes measured from photographs and MR images was analyzed using Excel® from Office 365.

[0083] LA was purchased from Merck Emprove (Darmstadt, Germany), and iohexol was purchased from Sigma Aldrich (St. Louis, MO, USA).

[0084] Pigs were pre-administered intramuscularly at conventional doses of dexmedetomidine (Domitor® vet, Orion Pharma, Sollentuna, Sweden) and a commercially available mixture of zolazepam and tyrethamine (Zoletil® vet 100, Virbac, Carros, France). Anesthesia was maintained with intramuscular buprenorphine (Vetergesic® vet, Orion Pharma) at 0.03 mg / kg, intravenous carprofen (Rimadyl® vet, Orion Pharma) at 4 mg / kg, and isoflurane (Attane vet, VM Pharma AB, Stockholm, Sweden) using a Servo 900 ventilator (Siemens, Munich, Germany). Before recovery from anesthesia, atipamezole (Antisedan® vet, Orion Pharma) was administered intramuscularly. For the first three days after surgery, the pigs were orally administered 2 mg / kg of carprofen twice a day.

[0085] The pig was placed with its right side down. A 6 cm incision was made lateral to the lateral process, from the costal arch to the iliac crest. The lumbar IVD was accessed using retroperitoneal techniques. The L3 / 4 IVD was incised, and 0.2 mL of LA preparation (n=6) or placebo (n=2) was injected under fluoroscopic guidance. The LA preparation contained LA (120 mg / mL) and iohexol (180 mg / mL), while the placebo contained iohexol only. The concentration was determined based on a pilot study on the effect of LA on collagen secretion from human NP cells (described in International Publication No. 2017 / 046030). In this series of in vivo experiments, the pH of the placebo preparation was adjusted to the same level as the active preparation (approximately 1.5) using hydrochloric acid. Adjacent IVDs were not injected and were used as negative controls. The volume of the pig NP was approximately 1 mL, and 0.2 mL was estimated to be an appropriate injection volume. The height and width of the obtained NPs (Figure 6a) were measured in the anterior-posterior direction (short vertical double arrow) and the lateral direction (short horizontal double arrow), respectively, and expressed in relation to the height (long vertical double arrow) and width (long horizontal double arrow) of the IVDs. Note the reduction in NP size 28 days (Figure 6b) and 84 days (Figure 6c) after LA treatment compared to the obtained NPs (Figure 6a). Figure 7 shows the data for NP height as a percentage of the total IVD height for each group, and Figure 8 shows the corresponding data for NP width.

[0086] Series 1 The objective of the first pilot series was to determine whether LA could potentially harden (induce fibrosis of) IVDs.

[0087] A total of eight female pigs (Yorkshire, Hampshire, and Landrace mixed background) with an average weight of approximately 30 kg at the time of surgery were used according to the method described above.

[0088] The animals were sacrificed 28 days after treatment, and the vertebrae from L1 to S2 were removed. The vertebral arches from L1 to S1 were removed to prevent interference due to the flexibility of the intervertebral discs. The distance between the lateral processes of the vertebrae was measured using a caliper in full ipsilateral or contralateral flexion at the cranial and caudal ends of the injected IVD. The difference in these distances was used as a measure of flexural stiffness. These values ​​were also recorded for untreated IVDs adjacent to the injected IVD in each lumbar vertebra. "Full flexion" was defined as the degree of flexion at which stiffness significantly increased with moderate manual flexion. The strength of manual flexion was not measured, but since flexion was performed by two different people and the same results were obtained, it was considered reliable enough to demonstrate in advance that the observed anatomical and histological changes actually result in biomechanical changes.

[0089] Furthermore, the IVD was cut in half and photographed. The width from side to side and the height from front to back of the obtained NP were measured and shown in Figures 7 and 8 as ratios to the total width and total height of the IVD, respectively.

[0090] Since the methods used were identical, the results for NP size in Series 1 and 2 (see below) were merged.

[0091] Significant differences in flexural stiffness were observed between LA-injected IVDs and placebo-injected IVDs, and between LA-injected IVDs and 16 naive IVDs (Table 2). While placebo-injected IVDs did not appear to have any effect on flexural stiffness compared to untreated IVDs, the fact that only two pigs received the placebo hindered statistical verification.

[0092] [Table 2]

[0093] Series 2 The objective of the second series (including 16 pigs) was to evaluate the safety and efficacy of the treatment, which was part of the regulations required by the Swedish Medical Products Agency to initiate human trials. All methods were as described above, with the exceptions described below. The pH of the placebo formulation was not adjusted, and since it was necessary to evaluate three survival times (2, 28, and 84 days) for placebo and two doses of LA (120 or 240 mg / mL in 0.2 mL), the number of animals was kept within reasonable limits by injecting them into three matched IVDs in each pig. In one animal group, LA or placebo was applied (externally) to an IVD outside the spinal foramen to evaluate tissue damage resulting from leakage or accidental injection from the IVD. Spine flexion stiffness was not measured in this experiment. Another difference between the two series was that the exposed tissue was histologically evaluated in the second series, but not in the first series.

[0094] The animals were divided into groups as shown in Table 3.

[0095] [Table 3]

[0096] The lumbar vertebrae were removed en bloc, pathological changes were visually evaluated, and the extradiscal tissue to which LA was applied was photographed. Specimens of spinal nerve and muscle tissue were collected, fixed in 10% formalin, and processed for microscopic examination with hematoxylin / eosin staining. The injected IVDs were cut in half, visually examined, and photographed. IVD samples were collected and processed for microscopic examination with hematoxylin / eosin. These were found to contain AF but very little NP; therefore, to improve the appearance of the IVDs, IVDs with vertebral fusion were decalcified to allow for the preparation of axial sections of the entire IVD stained with Masson's trichrome.

[0097] Series 3 In subsequent clinical trials, the effect of LA on NP was planned to be evaluated using MRI; therefore, the third series focused on the effect of LA (0.2 mL, 60 mg / mL) on sclerosis as measured by T2-weighted MRI. In addition, the effect of LA on the expression of type I and type II collagen was examined by immunohistochemistry (IHC). The visual changes after administration of 60 mg / mL of LA were similar to those described above.

[0098] MR images were acquired using a 7T small animal MRI system (Bruker Biospec). A single 50mm volumetric coil array was used (Tx / Rx). From the dissected vertebrae, attached muscles, spinous processes, transverse processes, and the posterior parts of the facet joints were scraped off to fit into the MRI system. T2-weighted (TR: 2500~2834ms, TE: 33~35.84ms), 2D TurboRARE transverse and sagittal sequences were used. TR and TE required adjustment for different specimens, making it impossible to maintain the same values ​​for all sequences within the field of view, leading to an increase in the pixel matrix affecting TR and TE. For transverse sequences, a slice thickness of 500μm, interslice distance of 750μm, and in-plane resolution of 166×166μm were used. For sagittal sequences, a slice thickness of 750μm, interslice distance of 2000μm, and in-place resolution of 166×166μm were used. In a lateral sequence of a single pig, the in-place resolution was 174 × 166 μm due to increased field of view that could not compensate for a high matrix size that did not significantly affect TR.

[0099] Images were analyzed using the Sante DICOM Viewer (version 8.1.5, Santesoft, Athens, Greece). Treated IVD was evaluated in all animals, and IVD at one level above the treated IVD was scanned as a control.

[0100] The size of NPs was measured using MR images and photographs of IVDs (see Figure 6). The results of visual analysis and MR analysis were correlated.

[0101] Immunohistochemical analysis of type I and type II collagen The tissue was dehydrated with an ethanol series and embedded in paraffin. Sections were microtome-cut, dewaxed, and incubated with polyclonal primary antibodies against type I (Abcam34710) or type II (Abcam34712) collagen. The antibodies were diluted 250-fold (type I) or 200-fold (type II) with phosphate-buffered saline containing 1% bovine serum albumin. Incubation was performed at room temperature for 60 minutes. The sections were then incubated with horseradish peroxidase-conjugated secondary antibody (Mach 2 Uni HRP, Biocare Medical) at room temperature for 30 minutes, and the immunoreaction was visualized using diaminobenzidine (Biocare Medical).

[0102] Figure 9 shows the effects of LA on AF (A, B) and NP (C-J). LA or placebo (0.2 mL) was injected into the IVD of anesthetized pigs. Animals were sacrificed 4 or 12 weeks after injection, and the IVD was cut in half. After fixation in 10% formalin, decalcification, and paraffin embedding, sections were cut to 5 μm and stained with hematoxylin and eosin (A, B) or Masson's trichrome (C-J). Fibrocartilaginous cells were observed in the AF of untreated IVDs (arrow in A), and multicellular chondrons appeared frequently after LA injection (240 mg / mL, 12-week survival; arrow in B). NP in untreated (extradiscal injection) IVDs (C) consisted of islands of notochord cells (asterisks) embedded in a faintly stained extracellular matrix. Collagen fibers are visible in NPs treated with LA (asterisk in D; 120 mg / mL LA, 4-week survival, and asterisk in E; 120 mg / mL LA, 12-week survival). Occasionally, dense connective tissue with chondrocyte-like cells replaces the normal NP structure (F; 240 mg / mL LA, 12-week survival). Newly formed blood vessels (venules; arrows in F) and osteoid islets (asterisks in F) can be observed in the connective tissue. The framed area in F is shown at high magnification in G, and newly formed blood vessels (arterioles, arrows) are shown in H. Cyst-like structures of various sizes, likely reflecting the "vacuum phenomenon," can be observed 4 weeks (I; 240 mg / mL) and 12 weeks (J, 120 mg / mL) after LA injection. Occasionally, small hemorrhages occur (arrows in I). The scale bar in all micrographs is 100 μm.

[0103] Because the central region of IVD was included, and because fibrous tissue is more clearly visualized with Masson's stain than with hematoxylin and eosin staining, most histological analyses were performed on the entire IVD section stained with Masson's trichrome.

[0104] During the two-day follow-up period, changes in bleeding and inflammation were occasionally clearly observed in animals injected intravertebral discs (not shown). Compared to animals injected with vehicle, the difference was not significantly pronounced in animals treated with LA, suggesting that these changes are related to the experimental method rather than a specific LA effect. Similar results were observed in spinal nerves and skeletal muscle exposed to LA outside the spinal cord (not shown).

[0105] As shown in Figures 9K (control) and 9L (LA injection), significant histological changes were observed two days after LA injection, characterized by the thawing of the extracellular matrix (blue region) and the lysis of notochord cells (white region with dark nuclei). Thus, both the cells and the matrix were in a state of thawing and degradation.

[0106] On day 28 of the follow-up, a clear difference was observed between the LA-treated sites and the placebo-injected sites. Animals injected with LA showed high-density bundles of fibrous tissue (Figure 9D). Similar to visual analysis, no differences were observed based on LA concentration. No fibrous changes were observed at the extradiscal injection sites. In addition, residual bleeding and cystic structures (Figure 9I) were observed 28 days after LA injection. The characteristics of the latter are unclear, but they may represent the "vacuum phenomenon" observed in Series 3 results.

[0107] At day 84 of the follow-up, a clear difference was observed between IVDs treated with placebo and those treated with LA. Histological changes were more pronounced from day 84 onward compared to day 28. In IVDs injected with LA, the following changes were observed in the NP: sclerosis (Figure 9D-J), cystic degeneration (Figure 9J), chondrometaplasia (Figure 9F, 9G), islets of osteoid (Figure 9F, 9G), and reduction of extracellular matrix. On day 84, blood vessels appeared in the fibrous tissue (Figure 9H). There was no clear difference in the degree of change between IVDs treated with high-dose or low-dose LA. Since multicellular chondrons were observed in AF (Figure 9B), changes after LA treatment were not limited to the NP.

[0108] Visual changes after administration of 60 mg / mL of LA were similar to those described above. These were reproduced on T2-weighted MRI, and as expected, the intensity of the hardened NPs was much lower (Figure 9B). The lamellar structure of the newly formed connective tissue was also visualized on MRI. There was a close correlation (correlation coefficient = 0.97) between the degree of hardening estimated from photographs and the degree of hardening estimated from the analysis of MR images. Dark, nearly circular areas were observed in four of the five IVDs injected with LA. These were prominent in two IVDs and distant in the other two (Figure 9B). These areas almost certainly reflect a vacuum phenomenon and may be related to the large cystic structures observed under a microscope.

[0109] Analysis of disc height and width between treated and control IVDs showed a very significant reduction in the height of treated IVDs, but not in width, as seen in Table 4. Relative disc height was expressed as the ratio of the height of treated IVDs to the height of untreated (control) IVDs. Similarly, relative disc width was expressed as the ratio of the width of treated IVDs to the width of untreated (control) IVDs.

[0110] [Table 4]

[0111] This effect is also confirmed in the MR images in Figure 12, where arrow A represents an untreated control IVD and arrow B represents an IVD that received 60 mg / ml of LA 30 days prior. As is clear from Figure 12, a significant reduction in the height of the treated IVD is observed.

[0112] In untreated IVD, immune responses to type I collagen were sparse in NP and high in AF. In contrast, immune responses to type II collagen were observed in both NP and AF. There was no clear difference in immune responses to type II collagen between treated and untreated IVD, but type I collagen was strongly induced in NP after LA treatment.

[0113] Example 2 This study was a randomized, double-blind, placebo-controlled, single-dose dose-escalation study primarily aimed to evaluate the safety and tolerability of intradiscal injection of placebo (Omnipaque®) or Omnipaque® combined with LA in 15 patients with chronic low back pain caused by intervertebral disc problems. A secondary objective was to evaluate the effects on NP and disc height using T2-weighted MRI.

[0114] Visual Analog Scale (VAS) scores for back pain and leg pain, as well as the Oswestry Disability Index (ODI), were used for exploratory purposes. While the sample size was not based on power calculations, it was considered appropriate for a single-dose dose-escalation study to provide initial safety data for three different doses of the LA formulation. The study is registered on the ClinicalTrials.gov website and in the EU Clinical Trials Registry. It was approved by the Stockholm Regional Ethics Committee (Approval No. 2016-2323-31 / 4) and the Swedish Healthcare Products Agency (Approval No. 5.1-2016-86227).

[0115] Patients were recruited at the Stockholm Spine Centre (Upplands Vasby, Sweden) between April 2017 and August 2018.

[0116] Fifteen patients were randomized to one of three dose groups. In each group, two patients were randomized to receive placebo, and three patients were randomized to receive LA at doses of 45 mg, 90 mg, and 180 mg (1.5 mL of 30 mg / mL, 60 mg / mL, and 120 mg / mL). The first two patients in each dose group were randomized to receive either LA or placebo. If no safety or tolerability concerns were identified within one week after administration (up to the third visit) (confirmed by a safety review committee consisting of two medical professionals and a non-voting chairperson), the remaining three patients were treated or given placebo (2:1). Before dose escalation, the safety review committee evaluated all safety data up to the third visit (one week after treatment). If safety or tolerability concerns were identified, the medication could be discontinued or the planned dose reduced.

[0117] The total duration of the patient trials was up to 14 months. Each patient underwent a screening visit within 60 days of their scheduled treatment date. An independent biostatistician at LINK Medical Research AB (Uppsala, Sweden) prepared the list of randomization numbers. Randomization was performed using the eCRF system (Viedoc®) at least 5 business days prior to the scheduled treatment date, taking into account the time required for the preparation of the investigational drug (IMP). The trial IMP and the reference IMP were identical in appearance. The kits were labeled with the randomization number but did not contain any information regarding the attributes of the formulation. This ensured that all staff and patients at the medical institution were blinded to the treatment code. An envelope containing the treatment code was provided to each randomized patient. The code envelopes were stored in a secure location with restricted access. In the event of an emergency where it was important for the principal investigator or other physicians to know whether a patient had received the active drug or placebo, the code envelopes were to be opened. However, no such emergency occurred, and the treatment code envelopes were not opened.

[0118] The test material in this study contained the active ingredient (S)-LA, which was provided on-site as a sterile solution in disposable syringes. The administered doses of LA were 45 mg, 90 mg, and 180 mg per 1.5 mL, corresponding to LA concentrations of 30 mg / mL, 60 mg / mL, and 120 mg / mL. The preparation for administration consisted of the contrast agent iohexol (Omnipaque®) and sterile water for injection, and was prepared on-site. The final concentration of iohexol in the injection solution was 388 mg / mL. Small amounts of tromethamine, calcium disodium edetate, and hydrochloric acid were also present. The solution was clear, colorless, or slightly colored.

[0119] LA (Batch C16077AA) was manufactured, packaged in vials, and labeled at Recipharm, Stockholm, Sweden. The other components of IMP (Omnipaque® [Batch No. 13407744] and Water for Injection) were purchased from Recipharm, Sweden. All components of IMP were shipped to the field pharmaceutical laboratory as one kit per patient, containing one vial of LA, one vial of Omnipaque®, and one vial of Water for Injection (active and placebo), along with instructions and patient-specific labels prepared by Recipharm. The final solution for injection was prepared sterile at the field pharmaceutical laboratory (Apoteket AB Hospital Pharmacy, Uppsala, Sweden), packaged in patient-specific syringes, and labeled with a "blinded" label for each patient. Syringes pre-filled and labeled with IMP for each patient were sent to the healthcare facility. If two injections are planned, two separate syringes are prepared (i.e., one syringe per IMP injection).

[0120] A placebo solution identical in appearance to the test sample was used as a reference treatment. The solution for administration was prepared in situ and contained iohexol contrast agent (Omnipaque®, batch number 13407744) diluted with water to a final iohexol concentration of 388 mg / mL, along with small amounts of tromethamine, calcium disodium edetate, and hydrochloric acid. The same volume (1.5 mL) as the test sample was injected.

[0121] This study was too small to statistically evaluate the effects of LA on NP, IVD height, VAS, and T2-weighted intensity of ODI; therefore, only descriptive statistics were performed. All statistical analyses were performed using SAS® version 9.4 (SAS Institute Inc., Cary, NC, USA). Results are presented by treatment group and, where necessary, as a total.

[0122] Descriptive statistics were used to summarize continuous data, and the following parameters were reported: the number of patients with evaluable observations and the number of patients with missing observations, the arithmetic mean and standard deviation, the median, the first and third quartiles, and the minimum and maximum values. Categorical data were presented as absolute and relative frequencies. Percentages were not provided when the absolute frequency was zero. Unless otherwise noted, the denominator in percentage calculations was the total number of patients in the applicable analyte population, including those with missing data. For variables with missing values, the number and percentage of patients with missing values ​​were shown.

[0123] On the day of treatment, a sedative or anxiolytic and an antibiotic were administered intravenously to the patient approximately 15 minutes before intradiscal injection. The patient was placed in the right lateral decubitus position, and the injection was performed using a two-needle technique under fluoroscopic guidance. After confirming that the intradiscal needle puncture was performed accurately, a small amount (approximately 0.5 mL) of the preparation was first injected slowly (30 seconds) to confirm that the distribution of the injection fluid was limited to the intervertebral disc and that there was no leakage. If no leakage occurred within 30 seconds, this procedure was repeated twice until the entire volume (1.5 mL) was injected. If leakage from the intervertebral disc occurred during the injection of the small or full volume (1.5 mL), the injection was stopped. Immediately after treatment, the patient was asked to remain in the prone (or lateral or supine) position for as long as possible (at least 4 hours after the final injection). All patients stayed overnight at the medical facility for observation and safety assessment after the injection. After leaving the medical facility, the patient was scheduled to be treated with analgesics and / or other means according to standard clinical trials. The patient was advised to limit physical activity for the first week.

[0124] Physical examination, blood pressure, heart rate, electrocardiogram (ECG), clinical chemistry, and hematology were assessed using standard methods. Pain during infusion and within 15 minutes thereafter was measured using a VAS scale (0-100 mm), and patients reported whether the pain was typical of their usual experience, based on its location and type. The distribution of Omnipaque® within the IVD was recorded according to the Dallas discogram scale. Local reactions to the infusion were recorded, and adverse events (AEs) were graded based on severity, intensity, and causal relationship with the treatment. Standard adverse events (SAEs) were defined according to the International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use (IMMED) guideline E2A.

[0125] All MRI studies were performed using the same scanner (Siemens 1.5T Avanto), with the following exceptions: In one placebo-treated patient and two high-dose patients, baseline MRI was acquired using a Siemens Symphony 1.5T scanner, while all other scans were performed using a Siemens 1.5T Avanto scanner. In addition, in two placebo-treated patients and one high-dose patient, baseline and 3-month MRI were performed using a Symphony scanner, while all other scans were performed using an Avanto scanner. T1 and T2-weighted sagittal, coronal, and transverse sections were acquired at 4 mm before and after gadolinium contrast injection.

[0126] Intervertebral disc height, measured as the maximum distance between two adjacent endplates, and the Pfirrmann grade were recorded at screening and tracked throughout the study period. Because the Pfirrmann criteria are not sensitive enough to detect small changes in intervertebral disc hydration, changes in NP intensity on T2-weighted MRI were scored by four evaluators who were unaware of the patient group assignments. Evaluators were instructed to score a clear decrease in intensity as "1" and no change as "0," regardless of the time elapsed since treatment.

[0127] Patients reported their levels of lower back and leg pain at the time points shown in Table 5 using a Visual Analog Scale (VAS) ranging from 0 to 100 mm. Physical impairment was assessed using the Oral Disease Inventory (ODI).

[0128] [Table 5]

[0129] The intensity of pain during injection was higher in the 45mg LA group compared to all other groups, but 15 minutes after injection, the pain levels were the same in all groups.

[0130] In this trial, a total of 24 adverse events (AEs) were reported from 11 patients (Table 6). All AEs were mild to moderate in severity. The most common AEs were injection site pain (reported by all groups) and back pain (reported by all groups except the 60 mg / mL LA group). Of the 24 AEs, 16 were potentially or likely to be treatment-related, 13 of which involved pain during or immediately after injection. All AEs resolved within the 3-month follow-up period. There were no sustained adverse events (SAEs), and none of the AEs led to patient withdrawal. During the extension phase, 6 AEs were reported by 4 patients, but they were mild in severity and not considered to be treatment-related.

[0131] [Table 6]

[0132] Post-treatment dehydration showed a dose-response trend (Table 7). Two representative examples of changes in NP strength after LA treatment are shown in Figures 10 and 11. Figure 10 is from patients treated with 60 mg / mL of LA (L4 / 5 and L5 / S1), and Figure 11 is from patients infused with 120 mg / mL of LA (L4 / 5). Images were obtained at screening, 3 months, 6 months, and 12 months (left to right). Similar to the results from porcine IVD, the loss of NP strength, which almost certainly reflects sclerosis, occurred in the periphery in most cases.

[0133] [Table 7]

[0134] Changes in NP intensity in T2-weighted MR imaging were scored as [1: clear reduction, 0: no change]. Scoring was performed by four evaluators who were unaware of the patient group assignments. A reduction in intervertebral disc height was observed during the study period (Table 8).

[0135] [Table 8]

[0136] Thus, a clear reduction in the height of the intervertebral disc is achieved by administering the composition of the present invention.

[0137] The composition of the present invention clearly reduces intervertebral disc height in a dose-dependent manner (Table 9). Although the number of patients in this study was small, dehydration of NPs is expected to be accompanied by intervertebral disc atrophy. The reduction in intervertebral disc height was similar to that observed after chemical nucleolysis (Table 9). There was no change in IVD width (not shown), demonstrating a reduction in IVD volume.

[0138] [Table 9]

[0139] It should be noted that the reduction in intervertebral disc height, even at the highest dose of LA, is comparable to that achieved with relatively low doses of chondriase.

[0140] Finally, changes in exploratory endpoints after treatment were evaluated. At baseline, no lower limb pain was reported in the 45 mg group. The mean lower limb pain at screening was 3 mm in the 90 mg group, 14 mm in the 180 mg group, and 26 mm in the placebo group. Overall, lower limb pain remained very low throughout the study period with no significant changes (data not shown).

[0141] The mean baseline back pain was 19 mm in the 45 mg group, 44 mm in the 90 mg group, 52 mm in the 180 mg group, and 50 mm in the placebo group.

[0142] At the time of screening, all treatment groups had moderate impairment in daily activities based on mean ODI values. No specific trends were observed in changes over time (see below).

[0143] [Table 10]

[0144] [Table 11]

[0145] Two days after injecting LA into pigs' IVD, thawing of the extracellular matrix accompanied by cell death and its disappearance was observed. These changes are the same as those observed after injection of typical chemonucleolytic agents, such as chymopapain. Therefore, LA can be classified as a novel chemonucleolytic agent, alongside known chemonucleolytic agents such as chymopapain, chondriase, ozone, and ethanol.

[0146] This study, supported by visual and MRI results, demonstrates that LA converts porcine NPs into connective tissue within one month. The rapid initiation of NP lysis, followed by slow, progressive fibrosis, is a typical effect of the characterized chemonucleolytic agent. Therefore, LA is, by definition, a newly identified chemonucleolytic agent.

[0147] LA injection caused a significant reduction in lateral flexibility, and we confirmed that the newly formed connective tissue stabilized the motor segment. In the hardened IVD, there was a high level of immune response to type I collagen, which may have contributed to the increased stability of the IVD. Since hardening continued and progressed even further after 3 months, it is reasonable to assume that the increase in rigidity persisted throughout the study period. Chondrocyte metaplasia was observed in AF, suggesting that AF remodeling may also have contributed to the reduction in flexibility.

[0148] Histologically, the appearance of cartilage tissue became evident after 3 months, and osteoid islets were observed in some IVDs. Such tissue transformation suggests that the reduction in lumbar vertebral flexibility may progress over a relatively long period. Another result was that angiogenesis occurred in fibrous tissue 3 months after LA administration. It has been suggested that angiogenesis is accompanied by new nerve innervation that can cause pain. However, a clear distinction between vascular-modulating afferent nerves and nociceptive afferent nerves has been rarely made. Moreover, angiogenesis and nerve sprouting in degenerated human IVDs appear to be induced by fissures in the AF. Since such fissures were not observed after LA injection, the mechanisms of nerve and vascular invasion, and the composition of nerve fibers (if sprouting actually occurs), may differ from those that occur spontaneously. Although there are similarities, it is important to recognize that the rapid hardening of IVDs caused by LA does not replicate the pathologically degenerated IVDs of patients suffering from low back pain. The most important difference in this regard is the absence of some features of pathological IVD degeneration, such as annular fissures and lamellar division, in studies using pigs.

[0149] The pig study involved a limited number of replicate experiments in some groups, so this limitation is unlikely to affect the conclusions.

[0150] LA has been shown to convert NPs into connective tissue in pigs, and MRI suggests that this also occurs in patients.

[0151] IVD hardening stabilizes it and reduces the range of motion, potentially decreasing the likelihood of hernia recurrence. Another effect of LA-induced hardening is the prevention of leakage of pain-causing molecules and sprouting of nociceptive nerves.

[0152] The treatment was safe and well-tolerated. A few patients reported relatively short-term lower back pain (cLBP) after the injection, but this was also observed in the placebo group. And, although limited by the small number of patients, the VAS and ODI results suggest that this treatment does not exacerbate cLBP.

[0153] MRI results showed that LA induced a reduction in the signal intensity of NPs. This may be due to increased degradation of glycosaminoglycans, which contribute to NP hydration and subsequent connective tissue proliferation. Similar to the case in pigs, the loss of signal intensity in patients was mostly observed in the periphery of the NP. In patients, there was a tendency for the height of the IVD to decrease after treatment. This effect was more pronounced than in the IVDs of pigs injected with LA, but the width of the IVD did not change in either humans or pigs. This indirectly but convincingly demonstrates that the volume of the IVD must have decreased. Since a reduction in IVD volume leads to a decrease in IVD pressure, which in turn reduces the size of the hernia and leads to symptom resolution or remission, reducing IVD volume is the goal of all chemopulosolytic therapy.

[0154] The test results demonstrate the concept that the composition of the present invention effectively reduces the height of the intervertebral disc and converts the intervertebral disc space into connective tissue.

[0155] Embodiments of this application demonstrate that the administration of lactic acid reduces the volume and height of the intervertebral disc, alters the tissue composition of the intervertebral disc, and changes the flexural stiffness of the treated IVD.

[0156] The present invention has been described in the drawings and the preceding description, but this description should be considered illustrative or illustrative and not limiting; the present invention is not limited to the embodiments disclosed. Other forms of the disclosed embodiments can be understood and achieved by a person skilled in the art practicing the claimed invention by examining the drawings, disclosure and claims. In the claims, the term “including” does not exclude other elements or processes, and the indefinite article “a” or “an” does not exclude plurals. The mere fact that certain means are described in different dependent claims does not mean that combinations of these means cannot be used advantageously. Reference numerals in the claims should also not be construed as limiting their scope.

Claims

1. A composition for use in the treatment of intervertebral disc (IVD) herniation, wherein the composition contains lactic acid and is administered to the intervertebral disc cavity containing the nucleus pulposus (NP) of the herniated intervertebral disc.

2. The composition according to claim 1, wherein the composition is administered in an amount effective to increase the concentration of lactic acid in the intervertebral disc space to at least 20 mmol / L.

3. The composition according to claim 1 or 2, wherein the composition is administered in an amount effective for dehydrating the herniated IVD.

4. The composition according to any one of claims 1 to 3, wherein the composition is administered in an amount effective in reducing the height of the IVD in the hernia condition.

5. The composition according to any one of claims 1 to 4, wherein the composition is administered in an amount effective in initiating fibrosis of the herniated IVD.

6. The composition according to any one of claims 1 to 5, wherein the concentration of lactic acid in the composition is at least 12 mmol / L.

7. The composition according to any one of claims 1 to 6, wherein the lactic acid is administered by local injection into the intervertebral disc space containing the NP of the herniated IVD.

8. The composition according to any one of claims 1 to 7, wherein the lactic acid is administered in a single dose of 2 mg to 1000 mg.

9. The composition according to claim 8, wherein the lactic acid is administered in a single dose on a single occasion.

10. The composition according to any one of claims 1 to 9, wherein the composition is an aqueous solution containing lactic acid.

11. The composition according to any one of claims 1 to 10, wherein the pH of the composition is less than 4.

0.

12. The composition according to any one of claims 1 to 11, further comprising a contrast agent.

13. The composition according to claim 12, wherein the contrast agent is an iodine-containing contrast agent, for example, iohexol.

Images