"Insertable Medical Device for Delivering Nano-Carriers of Mitomycin (And Its Analogues) to a Target Site, and Methods for Preparing and Using the Same" in Patent Application Approval Process
This patent application has not been assigned to a company or institution.
The following quote was obtained by the news editors from the background information supplied by the inventors: "Since the early stages of percutaneous vascular intervention, controlling restenosis has been an important measure of success, and a great deal of effort has gone into understanding its mechanisms. Restenosis is the result of a variety of mechanical and biological processes which, in balloon angioplasty procedures, typically begin immediately following balloon deployment, including acute vessel recoil, negative vascular remodeling and excessive neointimal proliferation.
"The most severe side effect of balloon angioplasty, i.e., abrupt vessel closure resulting from elastic recoil and plaque dissection, was effectively solved by the introduction of balloon-expandable stents. However, even with balloon-expandable stents, in-stent restenosis, caused by excessive neointimal proliferation, can still occur. Fortunately, drug-eluting stents (DES) have recently been developed which effectively reduce in-stent restenosis by eluting an antiproliferative drug and thereby reducing neointimal proliferation. As a result, drug-eluting stents (DES) have now become a mainstay in the treatment of coronary atherosclerotic disease.
"However, the demonstrated efficacy of drug-eluting stents (DES) in coronary intervention is still balanced by the small but real (and unpredictable) risk of very late stent thrombosis, which is believed to be due to delayed vascular healing as a result of (i) the initial antiproliferative effect (and associated late, incomplete stent apposition), or (ii) a hypersensitivity to the antiproliferative drug which is eluted by the stent to control excessive neointimal proliferation, or (iii) a hypersensitivity to the polymer coating which is added to the stent for carrying and releasing the antiproliferative drug, or (iv) combinations of the above.
"In recent years, drug-coated balloons (DCB) have emerged as a therapeutic alternative in the interventional field. With this technology, short-term transfer of antiproliferative drugs to the arterial wall is thought to be achieved, thus potentially reducing the negative effects associated with the longer-term drug release pattern commonly associated with polymer-based drug-eluting stent (DES) technologies. In small clinical trials, Paclitaxel-coated balloons (PCB) were shown to be safe and effective in reducing restenosis among patients with coronary in-stent restenosis and de novo peripheral vascular disease lesions. However, the long term safety and efficacy of these drug-coated balloon (DCB) and Paclitaxel-coated balloon (PCB) technologies, particularly with respect to integrating this technology with currently-approved technologies such as stents and atherectomy, and/or integrating these technologies into new clinical applications (e.g., small vessels, bifurcations, etc.), is still under investigation.
"The concept of delivering drugs into the vessel wall through a single-time dose application during an angioplasty procedure for the prevention of restenosis has been present for almost 20 years. However, despite extensive efforts to improve the efficiency of local arterial delivery, several studies have shown a marked variability in the site-specific uptake of the drugs and a rapid clearance of the delivered compounds, thus discouraging the widespread use of these technologies. In addition, the successful development of easy-to-use balloon-expandable stents has superseded the development of clinically functional local drug delivery technologies and the development of drugs offering an acceptable efficacy profile, thus heightening the general skepticism as to the potential commercialization of this technology.
"Several biological, technical and clinical aspects make balloon-based local drug delivery an attractive alternative to current drug-eluting stent (DES) technologies for the treatment of atherosclerotic vascular disease. First, in contrast to the clinical situation encountered by researchers and clinicians in the past, several antiproliferative agents with a successful record of clinical safety and efficacy are now clinically available. Second, the theoretical advantages which are associated with the homogeneous and uniform drug delivery that can be achieved using drug-coated balloons (DCB) may lead to greater therapeutic safety and efficacy. Third, the lack of an ongoing presence of both an antiproliferative drug and/or an irritating polymer coating on the stent (for carrying and releasing the antiproliferative drug) may lead to more rapid vascular healing, thus reducing any inflammation due to a hypersensitivity to those elements and resulting in a shorter time requirement for dual anti-platelet therapy.
"In order to avoid the side effects associated with the polymers used in polymer-based stent technologies, several non-polymeric approaches have also been cited in the literature. These non-polymeric approaches use microparticles or nanoparticles of the antiproliferative drugs deposited on the surface of the drug-coated balloons (DCBs). These antiproliferative drugs are then transferred from the drug-coated balloons (DCBs) to the vessel walls when the balloon is inflated. However, these non-polymeric approaches are generally based on modifying the surface of the balloons in order to provide depot effects for the antiproliferative drug. These surface modification approaches do not guarantee the uniform distribution of the microparticles or nanoparticles of the antiproliferative drugs across the treated area, thus negatively impacting the process of healing the treated area. Furthermore, such non-polymeric approaches have generally taken advantage of the chemical characteristics of highly lipophilic drugs such as Paclitaxel. In contrast, less lipophilic drugs such as Sirolimus and Mitomycin have not been successfully loaded onto the surfaces of medical devices unless controlled polymer-based delivery systems are used. Of course, such polymer-based delivering systems in turn introduce the hypersensitivity issues discussed above. As a result, it has heretofore been impractical to deliver less lipophilic drugs (e.g., Sirolimus and Mitomycin) using inflatable balloons.
"With advances in the use of nano-technology in the field of medicine, the development of nano-sized particles has gained importance in the field of local drug delivery. Generally, polymers are used to construct nano-sized particles containing the drugs and acting as local drug delivery agents. However, the use of a polymer as a drug delivery agent brings additional challenges to the various processes of drug transfer, drug release and long-term drug retention. In addition, these polymer-based nano-particles may induce inflammation in tissue due to the degradation process of the polymer at the treatment site. Furthermore, due to the degradation properties of the polymer, the antiproliferative drug may be delivered in an unpredictable manner, thus resulting in non-homogeneous healing ('edge effect and delayed healing'). In addition, drugs displaying different solubility profiles, such as Mitomycin, require further modification to enhance long term retention on, and absorption into, the arterial tissue.
"Thus there is a need in the art for improving the delivery and uptake of Mitomycin (and its analogues) and/or other antiproliferative drugs by preparing nano-carriers, utilizing an encapsulation matrix, so as to improve the lipophilic property of the Mitomycin (and its analogues) and/or other antiproliferative drugs. There is also a need in the art for an insertable medical device which can carry and deliver the Mitomycin (and its analogues) and/or other antiproliferative drugs (in the form of encapsulated nano-carriers) without requiring the physical surface of the insertable medical device to be modified. Alternatively, there is a need in the art for enhancing the release of the aforementioned drug nano-carriers by applying a release-promoting layer on the surface of the insertable medical device (e.g., on the surface of the balloons) so as to promote the release of the nano-carriers from the surface of the balloons. Additionally, there is a need in the art to facilitate the delivery and uptake of the Mitomycin (and its analogues) and/or other antiproliferative drugs without requiring the use of polymers."
In addition to the background information obtained for this patent application, NewsRx journalists also obtained the inventor's summary information for this patent application: "The present invention provides for the improved delivery and uptake of Mitomycin (and its analogues) and/or other antiproliferative drugs by preparing nano-carriers, utilizing an encapsulation matrix, so as to improve the lipophilic property of the Mitomycin (and its analogues) and/or other antiproliferative drugs. The present invention also provides an insertable medical device which can carry and deliver the Mitomycin (and its analogues) and/or other antiproliferative drugs (in the form of encapsulated nano-carriers) without requiring the physical surface of the insertable medical device to be modified. Alternatively, the present invention also provides for the enhanced release of the aforementioned drug nano-carriers by applying a release-promoting layer on the surface of the insertable medical device (e.g., on the surface of the balloons) so as to promote the release of the nano-carriers from the surface of the balloons. And the present invention provides novel methods and apparatus to facilitate the delivery and uptake of the Mitomycin (and its analogues) and/or other antiproliferative drugs without requiring the use of polymers.
"In one preferred form of the present invention, there is provided a nano-carrier comprising an antiproliferative drug encapsulated by a lipophilic enhancement agent.
"In another preferred form of the present invention, there is provided a method for forming nano-carriers, the method comprising:
"providing a solution of an antiproliferative drug and providing a solution of a lipophilic enhancement agent;
"combining the solution of the antiproliferative drug and the solution of the lipophilic enhancement agent so as to provide a solution of nano-carriers comprising the antiproliferative drug encapsulated by the lipophilic enhancement agent.
"In another preferred form of the present invention, there is provided apparatus for delivering nano-carriers to a patient, the apparatus comprising:
"an insertable medical device; and
"nano-carriers disposed on the outer surface of the insertable medical device;
"wherein the nano-carriers comprise an antiproliferative drug encapsulated by a lipophilic enhancement agent.
"In another preferred form of the present invention, there is provided a method for treating a patient, the method comprising:
"providing a nano-carrier comprising an antiproliferative drug encapsulated by a lipophilic enhancement agent; and
"administering the nano-carrier to the patient.
BRIEF DESCRIPTION OF THE DRAWINGS
"These and other objects and features of the present invention will be more fully disclosed or rendered obvious by the following detailed description of the preferred embodiments of the invention, which is to be considered together with the accompanying drawings wherein like numbers refer to like parts, and further wherein:
"FIG. 1 is a schematic view showing how encapsulated nano-carriers may be produced and mounted on an insertable medical device; and
"FIG. 2 is a schematic view showing the chemical structure of Mitomycin C."
URL and more information on this patent application, see:
Keywords for this news article include: Antineoplastics, Pharmaceuticals, Patents, Surgery, Therapy, Cardiology, Mitomycins, Paclitaxel, Restenosis, Inflammation, Nanoparticle, Heart Disease, Cardiovascular, Indolequinones, Nanotechnology, Catheterization, Hypersensitivity, Balloon Dilatation, Mitotic Inhibitors, Balloon Angioplasty, Surgical Technology.
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