FDA Approves Abbott’s Dissolving Stent System for Chronic Limb-Threatening Ischemia in Arteries Below the Knee

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Abbott announced that the FDA has approved the Espirit BTK Everolimus Eluting Resorbable Scaffold System, a dissolving stent that treats chronic limb-threatening ischemia (CLTI) in arteries below the knee. According to the company, the treatment is the first of its kind, designed to keep arteries open and deliver Everolimus as a part of vessel healing before dissolving completely. The system is made from materials similar to dissolving sutures, fully dissolving in three years’ time.¹

"At Abbott, we've recognized the significant burden of disease and limited treatment options available for people living with the most severe form of (peripheral artery disease [PAD]). That's why we're revolutionizing treatments with resorbable scaffold technology below the knee," said Julie Tyler, senior vice president of Abbott's vascular business. "Our resorbable program is focused on meeting unmet needs in the peripheral anatomy to help people live better and fuller lives."

According to data from the LIFE-BTK trial, which was published in the New England Journal of Medicine, 135 out of 173 patients treated with the dissolvable scaffold therapy avoided amputation above the ankle of the target limb, meeting the primary efficacy endpoint of freedom from this event after a year. Additionally, 88 patients were treated as part of the comparator angioplasty arm of the study, with only 48 of the group achieving the primary outcome.²

“The primary efficacy end point was observed (i.e., no events occurred) in 135 of 173 patients in the scaffold group and 48 of 88 patients in the angioplasty group (Kaplan-Meier estimate, 74% vs. 44%; absolute difference, 30 percentage points; 95% confidence interval [CI], 15 to 46; one-sided P<0.001 for superiority),” the study authors wrote. “The primary safety end point was observed in 165 of 170 patients in the scaffold group and 90 of 90 patients in the angioplasty group (absolute difference, -3 percentage points; 95% CI, -6 to 0; one-sided P<0.001 for noninferiority). Serious adverse events related to the index procedure occurred in 2% of the patients in the scaffold group and 3% of those in the angioplasty group.”

The Journal of Vascular Surgery defines CLTI as limb pain that occurs at rest, or impending limb loss that is caused by severe compromise of blood flow to the affected extremity. It is also considered the last stage of PAD as a result of inadequate blood flow being supplied to vital oxygen demanded by the limb. This results from critical limb ischemia (CLI), which eventually leads to CTLI.³

“…any patient with chronic ischemic rest pain, ulcers, or gangrene attributable to objectively proven arterial occlusive disease,” reports the Journal of Vascular Surgery. “CLI is not to be confused with acute occlusion of the distal arterial tree, but rather a disease process that occurs in a chronic setting of months to years and, if left untreated, ultimately leads to limb loss secondary to lack of adequate blood flow and oxygenation through the distal extremities. Given that CLI is a severe manifestation of PAD, these patients would be classified in the more severe ends of the Fontaine classification (stage III-IV) or the Rutherford classification.”

References

1. ABBOTT'S BREAKTHROUGH DISSOLVING STENT RECEIVES FDA APPROVAL FOR ARTERIES BELOW THE KNEE. Abbott. April 29, 2024. Accessed April 30, 2024. https://abbott.mediaroom.com/2024-04-29-Abbotts-Breakthrough-Dissolving-Stent-Receives-FDA-Approval-for-Arteries-Below-the-Knee

2. Varcoe RL, DeRubertis BG, Kolluri R, et al. Drug-Eluting Resorbable Scaffold versus Angioplasty for Infrapopliteal Artery Disease. N Engl J Med. 2024;390(1):9-19. doi:10.1056/NEJMoa2305637

3. Critical limb ischemia. JVS. January 2010. Accessed April 30, 2024. https://www.jvascsurg.org/article/S0741-5214(09)01783-2/fulltext