Positive data from Abbott Laboratories' Absorb bioresorbable scaffold have at least one researcher predicting that within five years they will be more widely used than permanent metal stents for the treatment of coronary artery disease.
But while Absorb is currently the leading bioresorbable scaffold, it could eventually be displaced by next-generation products, said Professor Patrick Serruys of Imperial College London. He pointed to Absorb’s fairly thick strut size, at 150 microns; thicker struts have been linked with recurrence of the vessel blockage.
“27 companies are working on this, and there’s not a day that I don’t see an improvement in the technology,” he said. Others in the space include Elixir Medical – which like Abbott has a CE marked device – Biotronik and Boston Scientific, which in July started clinical trials with its FAST scaffold.
Professor Serruys presented the positive Absorb data at the European Society of Cardiology meeting today, and the company also celebrated a victory in its Japanese trial of the device.
But these companies are some way behind Abbott, which has already filed for US and Japan approval for Absorb and obtained a CE mark. And now the group has replicated data from the Absorb II trial, which reported last year that the device was non-inferior to its best-selling Xience V drug-eluting stent at 12 months (Abbott moves to soak up more stent sales with Asborb data, September 15, 2014).
Two studies with Absorb were presented at the ESC today: Absorb Japan, designed to support Japanese approval and comparing the device with Xience Prime/Xpedition in patients undergoing percutaneous coronary intervention; and Absorb Stemi Trofi II, in which the scaffold went up against Xience in patients with the more serious form of heart attack known as ST-segment elevation myocardial infarction (STEMI).
Both showed non-inferiority versus the older, metal-framed drug-eluting stent.
The primary endpoint of the 400-patient Absorb Japan study was target lesion failure at 12 months – a composite of cardiac death, heart attack caused by a re-blockage of the vessel and need for a repeat procedure – which occurred in 4.2% of Absorb-treated patients and 3.8% of the Xience group.
The 191-patient Absorb Stemi Trofi II trial, meanwhile, looked at vessel healing at six months, measured by the intravascular imaging technique optical coherence tomography. The healing score was similar between treatment groups, at 1.74 in the Absorb arm and 2.80 in the Xience group.
When asked why doctors would choose to use resorbable devices rather than older – and cheaper – DESs with the outcomes being so similar, Professor Serruys said he expected the benefit with the former to be seen in two to three years, once the scaffold dissolved and the blood vessel returned to a more natural state.
This assumption will obviously need to be borne out in longer-term studies.
Next stop US and China
The next milestones for Absorb will be one-year results from the pivotal US Absorb III and Absorb China studies, which will both be presented at the Transcatheter Cardiovascular Therapeutics conference in October, along with two-year Absorb II data.
Absorb III is the big one – if positive it should support FDA premarket approval, expected in early 2016. The 2,000-patient study is comparing Absorb with Xience and aims to show non-inferiority on target lesion failure, the same primary endpoint as Absorb Japan.
The FDA green light should give Absorb the boost it needs, as sales in Europe have been sluggish. Credit Suisse analysts estimate that Absorb could bring in $825m in 2020, up from $142m in 2014.
Even if Absorb does get the nod in the US, Abbott will need to make its first-mover advantage count, with new and potentially improved devices not too far behind it.
|Absorb Stemi Trofi II||NCT01986803|