Abbott Dissolving Stent Granted Earlier-Than-Expected FDA Approval

Abbott today announced FDA approval of its Esprit BTK Everolimus Eluting Resorbable Scaffold System for the treatment of patients with chronic limb-threatening ischemia (CLTI) below-the-knee (BTK), the most severe form of peripheral artery disease (PAD). The Esprit BTK System, which saw approval earlier than analysts’ expectations of 2H24, is designed to keep arteries open and deliver Everolimus to support vessel healing through the minimally invasive insertion of a stent that dissolves over time.

“Just like a cast isn't needed after a broken bone heals, Esprit BTK System treats the diseased artery until it heals, then is resorbed into the body over time, leaving an open artery to restore blood flow to the leg and foot,” Jennifer Jones-McMeans, divisional vice president of global clinical affairs at Abbott’s vascular business, told MD+DI.

Standard of care for use below the knee has historically been balloon angioplasty — a small balloon delivered through a catheter to the blockage to compress it against the arterial wall, opening the vessel and restoring blood flow. However, this treatment modality has garnered poor short- and long-term results, many times resulting in the vessels becoming blocked again and needing further treatment.

“There hasn’t been innovation in this space since balloon angioplasty,” she said. “There is a significant need for new treatment options below-the-knee, as various other devices have failed to demonstrate improved outcomes due to the complex nature of the disease and difficulty in keeping arteries open in both the short- and long-term. Balloon angioplasty has been the interventional standard of care for treating people with CLTI but following the treatment, the vessel frequently becomes blocked again over time requiring additional treatment.

A first-of-its-kind dissolvable stent, the Esprit BTK System is made of material similar to that used in dissolving sutures and is implanted during a catheter-based minimally invasive procedure through a small incision in the leg. Esprit is indicated for improving luminal diameter in infrapopliteal lesions in patients with CLTI and a total scaffolding length up to 170 mm with a reference vessel diameter of > = 2.5 mm and < = 4.00 mm. Once placed and the blockage opened, the scaffold then helps heal the vessel and provide it support for about three years until strong enough to remain open on its own.

“Esprit BTK System is implanted through a catheter-based minimally invasive procedure to minimize risk for patients, reduce recovery time, and improve health outcomes,” Jones-McMeans said. “This procedure can be performed in both outpatient and inpatient settings. Implantation time varies based on the complexity of the patient's disease state and individually tailored treatment needs.”

Data from the company’s LIFE-BTK trial showed statistical superiority to angioplasty at one year on the primary efficacy endpoint of freedom from amputation above the ankle of the target limb, total occlusion of the target vessel, clinically driven target lesion revascularization (CD-TLR), and binary restenosis of the target lesion (74.5% vs 43.7%, P < 0.001).

On the primary safety endpoint, Esprit was shown to be non-inferior to percutaneous transluminal angioplasty (PTA), exhibiting “a composite of freedom from major adverse limb events (amputation above the ankle of the target limb and major reintervention) at 6 months and perioperative death (96.9% vs. 100%, P < 0.001 for non-inferiority),” BTIG’s Marie Thibault and Sam Eiber explained in their analysis of the approval.

Esprit also showed superiority in two secondary endpoints, including binary restenosis of the target lesion at one year, and freedom from amputation above the ankle of the target limb, occlusion of the target vessel, and clinically driven revascularization of the target lesion at one year.

The analysts said that when Esprit hits the market, she expects the system to have consistent use due to the limited treatments currently available. “Over time, we expect Esprit could enjoy consistent use given the difficult-to-treat patient population and limited effective alternative treatment options,” they said.

Additionally, according to the report, Abbott’s estimated ~29% market share in the BTK market is expected to rise in response to the approval.

“[Abbott] cites a ~$500M global BTK market, growing at a 9% CAGR, that includes an estimated $400M US market,” according to the BTIG report. “The US market consists of 230K BTK procedures; we anticipate this could expand with good treatment options given an under-diagnosed, under-treated patient population that has endured less than optimal clinical outcomes. Through atherectomy, balloons, guidewires, and other tools, [Abbott] estimates that it has a ~29% market share in the U.S. BTK market and expects to be able to keep accelerating growth.”

According to Jones-McMeans, the system will initially have a limited market release and then “we expect Esprit BTK System will be widely available by the fall.”