Monday, March 26, 2007


The American College of Cardiology is currently meeting at New Orleans. Dr Greg Stone, initially of Taxus fame (principal investigator for all Taxus trials so far), presented the results from Spirit III. The Spirit trials are the trials of the new stent made by Abbott Vascular (XienceV). This DES is arguably a second generation DES, using a the Vision stent platform and coated with the drug, everolimus, which is a -limus compound which is essentially a cytostatic agent.

The Spirit III study compares the Xience V against the Taxus stent. You may remember that not so long ago, Boston Scientific (makers of the Taxus stent) acquired Guidant (makers of the Vision stent) when Guidant was very near the completion of the Xience V studies. For the Boston Scientific/Guidant merger, it would appear that Boston Sc did not have enough cash, so Boston Sc teamed up with Abbott Vascular to buy Guidant (remember that at that time, JnJ, a rival of Boston Sc was almost closing the deal for Guidant). That resulted in Abbott with rights to the Xience V stent. Abbott, at that time was also developing the Zomaxx DES stent. So Abbott Vascular, a late started in Interventional Cardiology, ended up (not by design) with two DES stents. Since then, they have stopped work on the Zomaxx DES as the results were poorer then the Xience V. So now, Abbott seemed to be concentrating on the Xience V. Interestingly, Boston Sc also has a limited rights to the Xience V. Looks like Xience V will be co-marketted (I am not sure if that is the right term), by Abbott Vascular and Boston Sc (they then called this DES by another name - Promuse). So JnJ loses Xience V, Abbott gets Xience V by "default" almost, and Boston Sc gets Xience V and call it "Promuse ". More importantly perhaps, Boston Sc gets the CRM division of Guidant, which presumably was the intended target of their Guidant purchase. So much for the gossip, now back to clinical trial data.

The Spirit III results has just been released at the New Orleans ACC 2007. The Xience V was comared to the Taxus of Boston Sc. in 1002 patients in 65 test sites in USA. This trial was obviously intended to get data for US FDA approval. The patients were studied after 8 months and the primary endpoints were in-stent and in-segment late loss. Interestingly, the Guidant/Abbott Vascular investigators had chosen the right target. You all may remember a very similar study, the Endeavor III by AVE Metronic when AVE Metronic, chose to compare the Endeavor DES (ABT 578 of AVE Metronic on the Driver platform), against the Cypher stent ( JnJ ), and loss. I have always felt that the -Limus drug on the stents (sirolimus on Cypher, and ABT578, now called Zitarolimus on the Endeavor) is better then the paclitexal (on the Taxus). When Endeavor went against Cypher (in Endeavor III) Endeavor lost, and so Endeavor is still awaiting FDA approval. So Guidant (now Abbott Vascular) wisely chose to compare Xience V against Taxus. Of course we all expected that Xience V will win (hands down), and sure they did. Dr Greg Stone just told the audience in New Orleans that Xience V was superior to Taxus in all the primary end points. How come I am not surprised. But you must remember that the current problem in DES use currently is late stent thrombosis, and this trial does not address that. Over 8 months followup in Spirit III, you cannot tell late stent thrombosis, so the FDA has an interesting decision to make. Is this DES safe? Anyway, welcome Xience V into this crowded ( and getting more so ) DES market. We have actually been asked to use this Xience V stent. I found it very easy to use. It moves well because the Vision platform ( cobalt chromium thin struts are great ) is very flexible and trackable. I expect that following due process, the Xience V and later the Promuse of Taxus ( same DES ), should get FDA approval. More from ACC 2007 later.

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