The possibility of a safe, durable intervention with minimal risk of having to undergo a repeat procedure and no greater risk of late stent thrombosis is attractive for both patient and physician. It is with this ideal in mind that DISA Vascular has made substantial investments in a DES program over the past six years. The objective is to develop a truly safer DES that further enhances the inherently low restenosis risk of the company’s bare stent design philosophy. The design elements of the DES comprise a very low anti-proliferative drug and a benign, non-permanent polymer carrier.
Early work by the company – published in various international peer reviewed journals – demonstrated the potential to achieve this goal using an extremely low dose of paclitaxel (up to 1/15th of early generation PES). However, a late death at 13 months post PCI of one of the patients in the Stellium I first-in-man trial produced conclusive and sobering evidence that even this low dose produced signs of residual tissue toxicity at this late stage. Hence the company has recently shifted its development focus to the use of a limus drug, while retaining the erodible polymer and thin-strut stent platform concept. There is increasing evidence that limus drugs provide a wider therapeutic window while avoiding localised toxic effects, when compared to paclitaxel.
DISA Vascular is currently undertaking preclinical testing in a comprehensive dose-finding study in collaboration with Renu Vermani’s group in Washington DC, and is on track to finalise the clinical formulation for the new stent by the 4th quarter of 2010.