Biotech Values

[DewDiligence]

Abbott Advances ‘Absorb’ Disappearing Stent

[Please see #msg-54238257, #msg-36292361, and #msg-32869939 for background.]

http://online.wsj.com/article/SB10001424052748704471904576230671702390088.html

›MARCH 30, 2011
By JON KAMP

Abbott Laboratories is betting heart patients will benefit from a new type of arterial stent that dissolves away when it is no longer needed.

Stents are scaffold-like devices used to prop open clogged heart arteries. Most stents are made of metal. But Abbott's new device, called Absorb, is made from a plastic-like material called polylactide that is commonly used in surgical sutures. The Absorb scaffold—Abbott doesn't call it a stent—is designed to completely fade away in two years and to cease supporting arteries at six months.

Abbott won European regulatory approval for Absorb this year [#msg-58615702], but the company plans only limited marketing there until it gathers more supporting medical evidence next year. [Approval of medical devices in the EU does not require clinical trials that demonstrate efficacy.] The company doesn't expect to file an application seeking U.S. regulatory approval until 2015.

"I think it's a pretty smart idea," said Nick Ruggiero, a cardiologist with the Jefferson Heart Institute in Philadelphia who has no financial connection to Abbott.

Abbott must still convince doctors, used to inserting permanent stents, to consider a dissolvable alternative. But if Abbott delivers evidence to bolster the concept, it will have unique technology and a years-long lead on competitors [no one else is even close in terms of timing].

Abbott expects to charge more for the Absorb device than the permanent, medicated stents currently available, which cost around $1,500 to $2,000.

The global drug-coated stent market is worth about $4 billion. Abbott's top competitors include Boston Scientific Corp. and Medtronic Inc.

Clinical-study data have shown low rates of complications with Absorb, although it has been tested in a limited number of patients thus far [#msg-43664045, #msg-54720842]. Abbott expects to release one-year data on 101 patients at a medical conference next month, and hopes to launch randomized trials this year.

Stents are inserted into arteries where they are expanded with balloons. Newer versions, including Absorb, use medication to slow tissue growth that could prompt additional procedures. Today's top-selling stents, including Abbott's market-leading Xience devices, are made of metal.

Arteries need only temporary support to relieve a plaque-based clog, Abbott says. But today's stents stick around for life, which raises challenges. Arteries with metal cages in them aren't flexible and don't expand during exercise, says Richard Rapoza, head of research and development for Abbot's Absorb program. Stents can also make future bypass surgery trickier, among other potential complications.

After six months with a stent in place, "you are just interfering with the healing process," Dr. Rapoza said.

Still, it isn't clear if the Absorb device offers a worthwhile trade-off, said Renu Virmani, president and medical director at the CVPath Institute in Maryland, which researches heart disease. Doctors will have to work harder to pick the right device size and implant it carefully with Absorb, compared with metal stents, she says.

They are also thicker than Xience stents at a time companies are touting slender profiles that may leave less surface exposed to passing blood cells that can clot.

Absorb hasn't shown clot-related issues thus far. But its thickness may mean patients can't quickly get off anticlotting drugs that can carry bleeding risks and complicate care, doctors say.‹