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With one company now pulling back from the race to develop bioresorbable vascular scaffolds (BVS), Abbott's competitors may be having second thoughts on the safety of this technology.

The company's Absorb product remains the sole BVS to have won FDA approval -- and it may remain so for a while, as even Abbott itself is beginning to lose interest in the idea of the much-hyped "disappearing stent."

Now that -- scrapping development of its everolimus-eluting Renuvia BVS in late July -- where do the other BVS players currently stand?

Boston Scientific

Why did Boston Scientific halt its BVS program? "First-generation bioresorbable stents, like Abbott's Absorb, have demonstrated poor acute performance and increased safety concerns, limiting their use in real-world clinical settings and ultimately resulting in a market that is developing more slowly than previously expected," a company spokesperson explained to 番茄社区app, adding that higher safety risks associated with Absorb have already resulted in a recent FDA warning to U.S. physicians, and severe use limitations in Europe, Japan, Australia and other countries.

"While our Renuvia Bioresorbable Scaffold is a second-generation technology designed to overcome many of the limitations of first-generation [BVS], pursuing commercialization of that product is not a primary focus for us at this time," according to the company.

Six-month results of a small study on Renuvia use in patients with "noncomplicated medical histories" will still be presented at the Transcatheter Cardiovascular Therapeutics meeting this fall, the Minneapolis Star Tribune .

Abbott

The main player in the BVS market also appears to be backing away from bioresorbable technology as it renews its focus on metallic drug-eluting stents (DES).

"Absorb has become very much a niche product. That's for sure. And I would have wished for it to be a lot bigger than that," admitted Abbott CEO Miles White during an earnings call on July 20. "But Xience remains the best-in-class stent. That's still true. Do we need a bioabsorbable coated stent? I'll tell you, I think the bigger issue is I think we need an even more deliverable stent."

"And we will launch early next year Sierra, next generation of Xience, which will address that. So, that's what I think is our single most important focus right now. Do I think long-term that there are still improvements and performance improvements and so forth to make in stents, whether it's coating or material or deliverability etc.? I do. I am not going to detail what that plan is from our standpoint, but our next focus in stents is primarily that deliverability with Sierra," Miles emphasized.

An Abbott spokeswoman told 番茄社区app that the company is still committed to developing BVS technology, but declined to give a timeline for launching a second-generation device.

The Race is Still On

Amaranth Medical is another firm with a BVS program. A company representative told 番茄社区app, "Yes, Amaranth remains committed to their pipeline of bioresorbable scaffolds."

The company's sirolimus-eluting Aptitude device showed no scaffold thrombosis in a small 9-month study presented at EuroPCR. It is slated to win European regulatory clearance later this year, the representative noted, while Magnitude, boasting struts less than 100 µm thick, is under evaluation.

Other BVS competitors presented positive data at EuroPCR, including Biotronik's 150-µm DREAMS-2G, Elixir Medical's DESolve Cx, Shanghai MicroPort Medical's Firesorb, Reva Medical's Fantom, and Meril Life Science's MeRes100.

But clinicians remain unenthusiastic about BVS, at least from what they have seen so far.

"[BVS] technology is not ready for prime time. Companies and some opinion leaders have pushed this technology a step too far," said Marco Valgimigli, MD, PhD, of Switzerland's Bern University Hospital in an email. "I never claimed to be an expert of this technology because every time I have been exposed myself to that in the setting of clinical studies or clinical use outside studies I have always felt it was not suitable, at this current stage of deployment, for clinical use."

"We are now in a phase where the results of percutaneous coronary intervention procedures are highly predictable and satisfactory so the bar for new developments to do even better is very high. [BVS] is simply not there," Valgimigli continued.

When asked about the future of BVS technology, he predicted that "it will become mainstream only if and when from an engineering standpoint bioresorbable stents can provide the same radial strength of metallic DES at the same strut thickness ... We need to wait for this leap forward, if possible, to happen before testing once more in patients."

"Right now, bioresorbable stent technologies have promise, but this promise is as yet unrealized," agreed Ajay J. Kirtane, MD, SM, of Columbia University Medical Center/New York-Presbyterian Hospital. "It is very difficult to justify the up-front potential risk of this device without any demonstrable late benefits, which is why Absorb usage is low (and in my opinion should remain so given the present data)."

Kirtane said that a good BVS would have to show late benefits and not have any upfront risks over conventional DES.

"As such, I do think that it is worth pursuing with new and improved devices," he continued. "It's unfortunately just a long road to pursue (with considerable time and expense), which was likely one of the major factors leading to [Boston Scientific's] decision."

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