US approves first bioresorbable stent for coronary artery disease with Abbott's Absorb GT1 system

Abbott announced Tuesday that the FDA approved its Absorb GT1 vascular scaffold system, making it the first fully dissolving heart stent available to treat coronary artery disease in the US. Bram Zuckerman, director of the division of cardiovascular devices at the FDA's Center for Devices and Radiological Health, said the approval "offers a new treatment option for individuals who are candidates for angioplasty, but would prefer an absorbable device rather than a permanent metallic coronary stent."

According to Abbott, the Absorb stent is made of a biodegradable polymer similar to materials used in other types of absorbable medical devices, such as sutures. The stent is gradually absorbed by the body and disappears completely in about three years after implantation, leaving four small platinum markers embedded in the artery walls that help cardiologists identify where it was originally placed. Abbott said it plans to offer the device to US hospitals, starting with interventional cardiology centres that participated in Absorb clinical trials.

The FDA said approval was based on a review of data from the ABSORB III trial comparing the rate of major adverse cardiac events between Absorb and Abbott's metallic drug-eluting Xience stent among 2008 patients with myocardial ischaemia who were undergoing percutaneous coronary intervention. Results after one year showed that the rates were comparable for the Absorb and Xience devices, at 7.8 percent and 6.1 percent, respectively. The agency also noted that the rate of blood clots forming within the devices after one year was 1.54 percent for the Absorb group and 0.74 percent for controls.

Gregg Stone, chairman of the ABSORB clinical trial programme, explained that "no metal means the treated artery can pulse and flex naturally as demands on the heart change with everyday activities [and] may also reduce the potential of future blockages that occur with permanent metallic stents, [as well as allow] easier access to other treatment options should they prove necessary." George Vetrovec, a member of the FDA advisory panel that backed the device in March, remarked "this is presumably a better technology going forward, at least that's the theory, but it will take years to prove."

Commenting on the news, Evercore ISI analyst Vijay Kumar said "the key for the stent market will be whether pricing returns to rational levels and the success of the new bio-absorbable stent platforms." He added that a "perfect storm of events," including safety concerns and the economic downturn, have pushed Abbott, as well as Medtronic and Boston Scientific, to lower prices in recent years. According to Evercore, stent sales declined approximately 30 percent to $4.1 billion in 2014, compared with 2006 levels.

Abbott, whose Absorb GT1 vascular scaffold system is available in more than 100 countries, stated that it does not disclose the price of its stents. 

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