New Bioresorbable Scaffold, Magmaris, Delivers Positive Early Outcomes

PARIS, France—Relatively early results from a large registry of patients treated with the bioresorbable magnesium scaffold (Magmaris; Biotronik) suggests the device performs as well as second-generation drug-eluting stents and without the associated risk of adverse events, specifically scaffold thrombosis, according to investigators.

Presenting the results of the BIOSOLVE-IV registry at EuroPCR 2018, Stefan Verheye, MD, PhD (Antwerp Cardiovascular Center, Belgium), reported that the 12-month rate of target lesion failure was 4.6%, which was up from 2.5% at 6 months.

Among the 198 patients who received the Magmaris scaffold, there were no cardiac deaths, and only one reported case of definite/probable scaffold thrombosis, which occurred early. The thrombotic event, said Verheye, occurred in a “complicated” patient with a heavily calcified coronary artery who stopped dual antiplatelet therapy (DAPT) to undergo a minimally invasive direct coronary artery bypass surgery.

Biotronik initially planned to enroll 1,065 patients in the BIOSOLVE-IV registry but has since decided to increase enrollment by an additional 1,000 patients. “I think that’s important to take into account here because it underscores the fact the company does believe in Magmaris as a scaffold and as an alternative for these patients,” said Verheye.

The Magmaris Scaffold

Magmaris is a magnesium alloy-based bioresorbable scaffold that is still relatively thick at 150 µm, just like the now abandoned Absorb bioresorbable scaffold (BVS; Abbott Vascular). Unlike Absorb, however, the Magmaris scaffold breaks down faster, as it is completely resorbed by 1 year. Appearing to learn from the early mistakes of the ABSORB clinical research program, the Magmaris investigators stress adhering to good implantation techniques, specifically the 4P protocol: proper patient and lesion selection, proper scaffold sizing, predilatation for lesion preparation, and postdilatation.

Ron Waksman, MD (MedStar Heart & Vascular Institute, Washington, DC), one of the panelists during a session devoted to bioresorbable scaffolds, doesn’t believe the Magmaris scaffold poses the same risk of scaffold thrombosis seen with the Absorb BVS.

“Having said that, we have to take this very, very carefully not to repeat the mistakes made with Absorb,” said Waksman.

The Magmaris scaffold has CE Mark approval in Europe, but is not yet available in the United States. In September 2016, Waksman, along with Jean Fajadet, MD (Clinique Pasteur, Toulouse, France), and others, published preliminary recommendations on the use of Magmaris, suggesting the scaffold be used primarily in patients with stable angina and a long life expectancy. It’s not recommended in STEMI, cardiogenic shock, saphenous vein grafts, or in patients with poor medical compliance or contraindications to DAPT.    

Antonio Colombo, MD (San Raffaele Scientific Institute, Milan, Italy), said the BIOSOLVE-IV study suggests physicians can achieve “good clinical results even with a relatively short absorption time—we really don’t need to support the vessel very long.” Unlike the Absorb BVS, which is believed to take at least 3 years before it is completely resorbed, the Magmaris scaffold allows patients to avoid DAPT for extended periods of time.  

“It’s important because if we want to continue DAPT until full resorption—to help with the inflammatory reaction related to absorption—it means we don’t have to prolong DAPT for 2 or 3 years, which is a big burden,” said Colombo. Moreover, the faster absorption isn’t “penalizing” vessel mechanics for too long, he said.

Several other bioresorbable scaffolds are in development, including the DESolve novolimus-eluting scaffold (Elixir), and MeRes100 (Meril), Fantom (Reva Medical), and Fortitude, Magnitude, and Aptitude (Amaranth), all of which are sirolimus-eluting scaffolds. Strut thickness varies between the scaffolds, as does resorption time, with Magmaris being the fastest-dissolving device currently available.

At EuroPCR, Amaranth provided an early glimpse of data with their 98-µm scaffold, with investigators reporting a MACE rate of 6.3% at 9 months in 48 patients (two cases of periprocedural MIs). Reva Medical also presented data from the FANTOM II trial, reporting a 2-year MACE rate of 5.0% in 240 patients and a very late scaffold thrombosis rate of 0.4%.

Lessons Learned From ABSORB

In the bioresorbable scaffolds session, Gregg Stone, MD (NewYork-Presbyterian/Columbia University Irving Medical Center, New York, NY), highlighted important lessons learned from the ABSORB program, but also stressed the technology’s upside.  

“First of all, I think we have to keep our mind on the fact the bioresorbable scaffolds were designed to provide the mechanical support and drug delivery function of metallic drug-eluting stents within the first year and then completely resorb within 2 to 4 years, removing the nidus for very late adverse events,” said Stone. “This is a play to remove very late outcomes for our patients, but of course we need to be as safe as drug-eluting stents early.” 

Abbott Vascular stopped selling the Absorb BVS last year because of “low commercial sales” linked to the stent thrombosis rates being reported in clinical trials and postmarketing studies. At the time, the company said they were continuing to work on a next-generation bioresorbable device, but for the time being, the Xience metallic everolimus-eluting stent and the now FDA-approved Xience Sierra would form the “cornerstone” of its portfolio. 

During his presentation, Stone also highlighted the importance of the PSP implantation protocol, which included predilatation, appropriate sizing, and aggressive postdilatation. The implantation strategy was supposed to reduce the risk of target lesion failure/scaffold thrombosis associated with the Absorb BVS, but it was infrequently used in the trials. 

“We came in with a 157-µm device, where we didn’t use decent technique, and imaging was actually discouraged,” said Stone. “We’ve learned a tremendous amount, and I think with better technology, and with an appropriate scaffold-specific technique, we can get very close, if not equivalent, to metallic drug-eluting stents early. And then the promise comes after 3 years.”

Speaking to the future, Waksman questioned whether the second-generation bioresorbable scaffolds will need clinical trials showing superiority over current drug-eluting stents given the disappointment with the Absorb BVS. When a new metallic drug-eluting stent is introduced to the market, the device usually has to match the clinical outcomes of currently approved stents, such as Xience. Such superiority trials would be expensive and time-consuming, noted Waksman.

Chaim Lotan, MD (Hadassah Medical Center, Jerusalem, Israel), countered that bioresorbable scaffolds take longer to implant and are much more expensive than metallic drug-eluting stents. “If you bring in a new technology, it’s either the same—noninferior—or if you want to pay much more and have a complex procedure you have to show superiority,” said Lotan. The majority of patients receiving stents worldwide live in places that can’t afford these new bioresorbable scaffolds, he said.

For his part, Alexandre Abizaid, MD (Instituto Dante Pazzanese de Cardiologia, Sao Paulo, Brazil), thinks noninferiority at 1 year is sufficient, “but at some point down the line, maybe 3 to 5 years, we’re going to have to show some additional benefits.”