乌鸦传媒

SAN FRANCISCO -- A slew of studies in the ABSORB clinical series -- ABSORB II, ABSORB III, and ABSORB-China -- were reported at TCT 2015 today and once again the everolimus-eluting bioresorbable scaffold was non-inferior to an everolimus-eluting metal stent (Xience).

But by every measure the "disappearing" stent was numerically not quite as good as the comparator: for example, at 2 years, the device-oriented composite endpoint (cardiac death, target-vessel myocardial infarction, and clinically-driven target-lesion revascularization) was 7.0% versus 3.0% for the Xience stent (P =0.07).

Or, consider the results from ABSORB III -- the pivotal trial that will be presented to the FDA -- target lesion failure at 1 year was 7.8% in the Absorb arm versus 6.1% for Xience, a difference of 1.7%, which was well within the pre-specified 4.5% noninferiority margin, P=0.007 for noninferiority versus P=0.16 for superiority.

And ABSORB China, which addressed the issue of late lumen loss with 1-year angiographic data -- 0.19 mm ±0.38 mm for the bioresorbable stent versus 0.13 mm ± 0.38 mm for cobalt-chromium control -- yielded a difference that did meet the pre-specified limit for non-inferiority and closely mirrored results from ABSORB Japan reported last month at the European Society of Cardiology meeting.

In addition to being reported among late-breakers here, ABSORB III was simultaneously published in The and ABSORB China was published in the Journal of the American College of Cardiology.

All the ABSORB studies continue to confirm the bioresorbable stent as non-inferior to Xience, which is considered a best-in-class drug-eluting stent, yet in each comparison Absorb fell numerically short of the performance of Xience, although never so much as to be statistically significant.

Asked if those less than stellar numbers could be problematic for either approval or for eventual uptake, especially since Absorb is likely to be more expensive than metal drug-eluting stents, , from the Linder Research Center in Cincinnati, said it "was not my job to set the price."

Moreover, Kereiakes, who presented the ABSORB III results at a press conference, said the design concept of the Absorb scaffold -- reopening an artery without permanently implanting metal in an artery -- was so appealing that it would gain acceptance on that basis even without demonstrating superiority.

He added that the true benefit of Absorb is unlikely to be apparent "at 1 or 2 years" because it takes at least 3 to 4 years for the scaffold to be fully absorbed and the vessel to be "uncaged."

Press conference discussant of University Hospitals in Cleveland, said, "We do 13,000 procedure in six angio hospitals each year and we are going to face the same questions ... why are you paying more?"

Simon agreed that it is too early for observable clinical benefits, but "there is going to need to be some patient-centered outcome benefit."

That said, Simon noted that hospital systems may offer bioresorbable technology in response to patient demand: "We will pay a little more for a device that patients are asking for because they are concerned about rigid cages."

But from Lukaskrankenhaus Neuss in Germany, who was on the panel at the press conference, disagreed based on the experience in Germany, where Absorb is currently available. He told 乌鸦传媒 that it will be "8 to 10 years before Absorb will be able to demonstrate superiority and superiority is what will be needed to convince the insurers to pay for it."

The "story" -- a device that "disappears" leaving only a naturally functioning vessel in its wake -- is "not enough to impress payers," Haude said.

Currently, Absorb scaffolds are implanted in about 10% to 15% of cases in Germany and outcome data from those are collected in registry. Thus far, the registry has accumulated 3 to 5 years of data, and "we are seeing no difference," Haude said.

Absorb costs about $1,340 in Germany versus only about $170 for a Xience stent, which is why cost is becoming more of an issue. "We are going to need to show superiority."

ABSORB III randomized 2,008 patients with stable or unstable angina in a 2:1 ratio to receive Absorb (n=1,322) or Xience (n=686). The primary endpoint was target lesion failure (cardiac death, target-vessel myocardial infarction, or ischemia-driven target lesion revascularization) at 1 year.

The second study, ABSORB China, assigned 480 eligible patients with one or two de novo native coronary artery lesions to Absorb (n=241) or Xience (n=239). The primary endpoint was angiographic in-segment late loss, defined as the change in minimal lumen diameter from post-procedure to 1 year, and powered for non-inferiority with a margin of 0.15 mm.

And ABSORB II was a randomized, single blind, active-controlled trial that randomized 335 patients to Absorb and 166 to Xience. At 2 years, the all-cause mortality rate was 1.2% for Absorb versus 0.6 with Xience; MI rate was 5.8% versus 2.4%; and definite or probable stent thrombosis rate was 1.54% versus 0.0%.

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