As interest in vulnerable plaque heats up, medical device companies hope to capitalize on their earl y lead. But as vulnerable plaque shifts therapies from structural to biological, that lead many not last long. The second of a two-part series.

The big news out of this year's TCT meeting in September wasn't really news at all. The final results of the SIRIUS clinical trial, assessing restenosis rates and other clinical measures of the sirolimus-coated drug-eluting stent (now being marketed in Europe by Cordis Corp., a Johnson & Johnson operating company and soon to be available in the US) weren't all that different from the preliminary data previewed in May at the Paris Course on Revascularization.

ImaRx Therapeutics Inc. aims to use a diagnostic contrast agent as a vehicle for drug and gene delivery. The company will encapsulate a therapeutic payload in a synthetic microbubble, inject it into the body, then apply ultrasound across the skin to rupture the microbubble at the targeted site. Shockwaves from the rupture are thought to permeate capillary walls and drive the drug or gene instantaneously into the targeted tissue.

Innovative device companies have always had to contend with the Sword of Damocles of unexpected technological obsolescence, but for would-be developers of interventional devices for the prevention of restenosis, the sword is dangling perilously close. In the RAVEL trial, a 238-patient clinical trial on a drug eluting stent, treated patients experienced 0% restenosis compared to 26% in the control group. Now, device developers with alternatives to stents reposition themselves to sustain businesses in the face of potentially shrinking target markets. Many argue that they will serve certain applications better than stents; others hope to work with drug-coated stents to enhance performance, many believe that economics will leave room for alternative approaches, and still others are getting out of the coronary business entirely.