News Column

"Bioabsorbable Medical Devices and Methods of Use Thereof" in Patent Application Approval Process

July 18, 2014



By a News Reporter-Staff News Editor at Drug Week -- A patent application by the inventors Milner, Keith R. (West Lafayette, IN); Carlson, James M. (Lafayette, IN); Charlebois, Steven (West Lafayette, IN); Gearhart, Krista N. (Lafayette, IN); Swift, Richard A. (South Bend, IN), filed on March 7, 2013, was made available online on July 3, 2014, according to news reporting originating from Washington, D.C., by NewsRx correspondents (see also Patents).

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: "It has become common to treat a variety of medical conditions by introducing an implantable medical device partly or completely into the esophagus, trachea, colon, biliary tract, urinary tract, vascular system or other location within a human or veterinary patient. For example, many treatments of the vascular system entail the introduction of a device such as a stent, catheter, balloon, wire guide, cannula, or the like. However, when such a device is introduced into and manipulated through the vascular system, the blood vessel walls can be disturbed or injured. Clot formation or thrombosis often results at the injured site, causing stenosis or occlusion of the blood vessel. Moreover, if the medical device is left within the patient for an extended period of time, a thrombus often forms on the device itself, again causing stenosis or occlusion. As a result, the patient is placed at risk of a variety of complications, including heart attack, pulmonary embolism and stroke. Thus, the use of such a medical device can entail the risk of precisely the problems that its use was intended to ameliorate.

"A device such as an intravascular stent can be a useful adjunct to percutaneous transluminal angioplasty (PTA), particularly in the case of either acute or threatened closure after angioplasty. The stent is placed in the dilated segment of the artery to mechanically prevent abrupt closure and restenosis. Unfortunately, even when the implantation of the stent is accompanied by aggressive and precise antiplatelet and anticoagulation therapy (typically by systemic administration), the incidence of thrombotic vessel closure or other thrombotic complication remains significant, and the prevention of restenosis is not as successful as desired. Furthermore, an undesirable side effect of the systemic antiplatelet and anticoagulation therapy is an increased incidence of bleeding complications, most often at the percutaneous entry site.

"Stents coated with a bioactive material such a paclitaxel, sirolimus or a sirolimus derivative have offered a means of overcoming such problems. Such devices deliver the bioactive material directly into a body portion during or following a medical procedure, so as to treat or prevent such conditions and diseases, for example, to prevent abrupt closure and/or restenosis of a body portion such as a passage, lumen or blood vessel. However, the use of drug-eluting stents presents some potential drawbacks. Such stents are typically formed from metal and may cause a number of complications. These include a predisposition to late stent thrombosis, prevention of vessel remodeling, inhibition of surgical revascularization and impairment of later medical imaging.

"Bioabsorbable stents offer a means of overcoming some of these problems. These stents are typically formed of a bioabsorbable metal or polymer and degrade over time once implanted, thus eliminating the long-term use of antiplatelet therapy, without increasing the risk of stent thrombosis. In addition, bioabsorbable stents do not interfere with subsequent diagnostic imaging evaluations. However, the use of such stents may introduce additional problems, such as premature absorption of the stent structure resulting in stent collapse and blockage of the vessel."

In addition to the background information obtained for this patent application, NewsRx journalists also obtained the inventors' summary information for this patent application: "One aspect of the present invention provides an implantable medical device including a bioabsorbable base material and a coating layer on at least a portion of the surface of the base material. The coating layer provides for a controlled absorption of the base material when the device is implanted. In certain embodiments, the bioabsorbable base material is a bioabsorbable metal, a bioabsorbable polymer or a mixture of these materials. In another embodiment, the structure is encapsulated (i.e. completely covered) by the coating layer.

"In certain embodiments, the coating layer includes a bioactive, either alone or in combination with other material. In one embodiment, the bioactive controls the absorption of the base material when the device is implanted. The bioactive can be paclitaxel and can include dihydrate paclitaxel. In various embodiments, the coating layer reduces the absorption of the base material when the structure is implanted by at least 10% or 20% or 30%.

"Another aspect of the present invention provides a method of locally delivering a bioactive agent within a body vessel. The method includes inserting an implantable device as described into the vascular system of a patient and radially expanding the medical device within the body vessel to bring tissue in contact with the device, delivering the bioactive agent to the tissue. In one embodiment, the expandable medical device is a vascular stent. In another embodiment, the coating layer includes dihydrate paclitaxel, which provides for a controlled absorption of the base material.

BRIEF DESCRIPTION OF THE DRAWINGS

"FIG. 1 shows a coated endoluminal medical device.

"FIGS. 2A-C show cross sectional views of embodiments of a portion of the medical device of FIG. 1. FIG. 2A shows an embodiment having a coating on the luminal, abluminal and side walls of the device. FIG. 2B shows an embodiment having a coating on the abluminal and side walls of the device. FIG. 2C shows an embodiment having a coating surrounding the abluminal and luminal walls of the device."

URL and more information on this patent application, see: Milner, Keith R.; Carlson, James M.; Charlebois, Steven; Gearhart, Krista N.; Swift, Richard A. Bioabsorbable Medical Devices and Methods of Use Thereof. Filed March 7, 2013 and posted July 3, 2014. Patent URL: http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=%2Fnetahtml%2FPTO%2Fsearch-adv.html&r=1640&p=33&f=G&l=50&d=PG01&S1=20140626.PD.&OS=PD/20140626&RS=PD/20140626

Keywords for this news article include: Antineoplastics, Drugs, Patents, Taxoids, Therapy, Terpenes, Paclitaxel, Hydrocarbons, Cycloparaffins, Organic Chemicals, Mitotic Inhibitors.

Our reports deliver fact-based news of research and discoveries from around the world. Copyright 2014, NewsRx LLC


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Source: Drug Week


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