PANDA III: Distinct elution, absorption rates with bioresorbable DES offer comparable clinical outcomes

A uniquely-designed, sirolimus-eluting, bioresorbable stent was noninferior to an existing sirolimus-eluting stent for target lesion failure at 1 year, according to results from the PANDA III trial presented at the annual TCT Scientific Symposium.

In the prospective, randomized, multicenter trial, Bo Xu, MBBS, of Fu Wai Hospital, Beijing, and colleagues enrolled 2,348 patients with symptomatic CAD, silent ischemia or ACS from 46 centers. All patients were eligible for PCI.

The investigators randomized patients in a 1:1 ratio to treatment with a poly(lactic-co-glycolic acid) sirolimus-eluting stent (SES) incorporating an electro-grafting base layer (BuMA, SinoMed) or a polylactide SES (Excel, JWMS).

The primary endpoint was target lesion failure at 1 year, a composite endpoint consisting of cardiac death, target vessel MI or ischemia-driven target lesion revascularization. The study was powered for consecutive superiority and noninferiority analyses. Follow-up was conducted at 30 days, 6 months and 1 year.

At final follow-up, the primary endpoint was met in 6.4% of patients in theBuMA cohort and 6.4% of patients in the Excel cohort (difference, 0.06%; P for non-inferiority = .0003).

Comparable 1-year results were also observed with BuMA and Excel for each of the individual components of the target lesion failure endpoint:

Perspective from Aloke V. Finn, MD

cardiac death, 1.2% vs. 1.3%; difference, -0.1% (HR = 0.93; 95% CI, 0.45-1.93);
target vessel MI, 4.3% vs. 4.9%; difference, -0.6% (HR = 0.87; 95% CI, 0.60-1.27); and
ischemia-driven target lesion revascularization, 1.9% vs. 1.2%; difference, 0.7% (HR = 1.57; 95% CI, 0.80-3.07).

With BuMA compared with Excel, however, the rates of definite/probable stent thrombosis at 1 year were 0.5% vs. 1.3%, respectively (P = .047) in the intention-to-treat group and 0.4% vs. 1.3% (P = .01) in the per-treatment evaluable group.

“In the multicenter randomized trial, the BuMA SES was noninferior to the Excel SES for the primary endpoint of target lesion failure at 1 year,” Bo said. “The PGLA polymer-based BuMA SES was associated with a lower incidence of stent thrombosis compared to the PLA-polymer-based Excel SES, consistent with the previous findings of enhanced strut coverage with this device.” - by Jennifer Byrne

Disclosures: The researchers report no relevant disclosures.

Reference: Xu B, et al. PANDA III: A Prospective Randomized Trial of Two Sirolimus-Eluting Bioresorbable-Polymer-Based Metallic Stents With Varying Elution and Absorption Kinetics. Presented at: TCT Scientific Symposium; Oct. 11-15, 2015; San Francisco.

Perspective

Aloke V. Finn, MD

This study is very interesting because it is a strategy study. As we move forward in interventional cardiology, we’re moving toward erodible polymer systems, or disappearing polymers. But no one yet knows the optimal drug duration or optimal polymer duration for this type of system. How long should the drug elute for? How long until the polymer disappears? What’s the ideal situation?

This study essentially shows us that stent systems that elute drug within 30 days, and get rid of polymer within 3 months, are superior to systems where drug elution is longer and polymer elution is longer. Importantly, it also shows longer-duration drug and polymer encourages stent thrombosis, because the stent thrombosis rate was higher in the Excel arm than in the BuMA arm.

What we learn from this is that when we are designing new systems, we want them to have drug durations that are as short as possible, because we want to encourage healing.

Aloke V. Finn, MD

Assistant professor of medicine, department of cardiology

Emory University School of Medicine

Disclosures: Finn reports sponsored research agreements with Medtronic and Boston Scientific.