Abbott Tests Bioresorbable Scaffold in Hope of FDA Approval

First there were stents. Then came drug-eluting stents. Now the latest battleground in the cardiovascular intervention field is in bioresorbable scaffolds.

Abbott's Vascular division was first to debut their product, the Absorb, which, having done its job, dissolves harmlessly in about two years. Absorb was granted CE Mark approval in 2011, but has yet to get the nod from FDA.

However, Absorb is no longer alone in the marketplace. Tiny Elixir Medical Corp. (Sunnyvale, CA) has also garnered the CE Mark for its DESolve fully bioresorbable DESolve scaffold for coronary artery disease, and in January announced the device's first commercial implant. Significantly, perhaps, Elixir says its offering dissolves in one year versus the two-year lifespan of Abbott's product.

Meanwhile, Abbott has concluded enrollment for its Absorb III 2000-patient trial, data from which the company hopes will be sufficient to convince FDA to give its approval. The company has also completed enrollments in similar studies in China and Japan. Abbott says it has an eye towards commercial launches in the three countries that account for more than half the stents implanted worldwide.

Abbott explains that Absorb works by opening a blocked vessel and restoring blood flow to the heart similar to a metallic stent. However, unlike a metallic stent, Absorb dissolves over time, potentially leaving behind a more flexible vessel because it is free from a permanent metallic stent which cages the vessel.

Absorb is referred to as a scaffold to indicate that it is a temporary structure, unlike a metallic stent, which is a permanent implant. Absorb is made of polylactide, a naturally dissolvable material that is commonly used in medical implants such as dissolving sutures.

Abbott's Absorb III randomized clinical trial will evaluate the potential benefits of Absorb in people with coronary artery disease, a narrowing of one or more arteries that supply blood to the heart. The primary endpoint of Absorb III is the rate of target lesion failure (TLF) at one year. TLF has been defined as cardiac death, target-vessel myocardial infarction, or ischemia-driven target-lesion revascularization. TLF rates are a combined measure of the safety and effectiveness of Absorb, which Abbott intends to compare with the company's Xience family of drug-eluting stents.

"The rapid completion of enrollment in the Absorb randomized trials is a testament to the interest among doctors and patients in advancing new options to treat heart disease," said Gregg Stone, MD, director, cardiovascular research and education, Center for Interventional Vascular Therapy, Columbia University Medical Center, in Abbott's press release announcing the completion of enrollment. "Absorb represents an entirely new approach to helping people with heart disease by doing the job of a metallic stent, but then disappearing after its work is done, giving people the opportunity to live their lives free of a permanent metallic device implanted in their arteries."

Stephen Levy is a contributor to Qmed and MPMN.