Drug-eluting stents (DES) slowly release paclitaxel or similar meds to prevent restenosis of coronary arteries. In recent years they’ve become the standard, replacing plain metal stents. MIT’s Technology Review has the story on corporate jockeying between three companies — Johnson & Johnson, Boston Scientific, and Angiotech — in the race to create and dominate the field.
Taxus was arguably the most successful new medical product in history, netting more than $1.4 billion in sales in its first nine months in the U.S. alone. And that’s despite the divergent business models of the companies that created it…
…creating the Taxus stent was not easy. A critical technical hurdle was the development of a coating for the stent that would release the paclitaxel slowly for about six months after surgery, after which the scarring response dampens. Angiotech had already tackled the problem, but Boston Scientific preferred to develop its own technology.
That left Angiotech on the sidelines as Boston Scientific methodically designed and developed its new stent. The biggest questions were about drug dosage and rate of release. Barry started with a large dose just to show that the drug-coated stent would indeed work in pig arteries. Satisfied that it had the desired effect, he performed a series of follow-up studies, each time halving the drug dose until he found a minimum effective dose.
The next step was to tinker with the polymer to find the optimum rate of release. Restenosis is essentially a case of the healing process getting carried away, with smooth-muscle cells migrating to the site of the injury with such exuberance that the artery is once again blocked. Paclitaxel inhibits that process, but Barry didn’t want to shut it down completely. He used trial and error to find a polymer with a drug release rate that would allow just enough cell migration to promote healing yet prevent it from going overboard.
Each study took three to six months to complete. Some of them could be done concurrently, but other studies had to be done consecutively, and the development dragged out.
It’s an intriguing tale of science and business — ultimately, Boston Scientific’s slow, methodical approach won the day, but that had more to do with luck: J&J’s DES came out first but suffered distribution problems, giving cardiologists a reason to change horses.
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