Products in Development

Since the development of bare stents, there have been many significant improvements in design. Though many of these changes have been largely empirical, there has been steady progress in stent design and increases in efficacy. It is likely that drug eluting stent design will follow this same paradigm. Many different manufacturing techniques and structural designs are common in bare metal stent development and it is likely that these will carry over to drug eluting stents. In addition, drug eluting stents can employ many different drugs and delivery strategies and mechanisms. In the near future it will be common to see drug eluting stents of all conceivable materials, shapes, sizes, and functional agents.

In general, most corporations are reluctant to disclose specifics about products in development, but it is known that there many at this time. Many stents use drugs and drug delivery systems similar to products currently produced. Drug eluting stents that employ newer polymers and drugs are generally farther from the market.

Guidant Corporation has publicly announced the projected release of their CHAMPION Drug Eluting Stent System in 2005. This will follow the successful completion of the 975-patient FUTURE IV trial and, presumably, FDA approval. This stent differs from the current designs in that the drug it releases is everolimus, an immunosuppressant similar to sirolimus. Following the release of this stent, Guidant plans to use their everolimus eluting system on a new cobalt-chromium based scaffold in 2006 (MULTI-LINK VISION TM ).[1,2] Many other companies such as Medtronic Abbott, Quannam, Bio Compatibles, and BiodivYsio have products in clinical trials but are unwilling to speculate when they will come to the market.

There are a myriad of drugs currently employed in eluting stent designs in early clinical trials and in the pre-clinical trial phase. The following table shows all publicized drug eluting stent designs in development.[3]

Besides the drug and the frame, there are other components of the stent that are being revised. Patents have recently been approved by the United States Patent & Trademark Office (USPTO) for new uses of hydrogel as a hydrophobic macromer entrapping the therapeutic agent of a drug eluting stent [4]. Biodegradable polymer designs have also been patented to support and encapsulate drugs on stents.

One of the most recent patents approved for drug eluting stents may be of particular importance in the future design of these devices. This patent introduces a hydrophobic polymer that is covered with linked heparin as the outer layer of the structure. This is aimed at preventing thrombosis in addition to the anti-restenosis properties of the drug and stent itself [5]. A heparinized stent coating may also help to alleviate some of the early clotting problems encountered with the current drug eluting stents.

Although much of the information pertaining to new technologies is closely guarded, these disclosures paint a bright picture for the advancement of all facets of stent design and use.