Penumbra 3D Stent Retriever Plus Aspiration Trial Meets Primary Endpoints

July 27, 2016—Penumbra, Inc. announced that its 3D stent retriever revascularization device used in conjunction with Penumbra aspiration devices demonstrated noninferior safety and efficacy compared to using Penumbra system aspiration devices alone, meeting the primary endpoints set in the Penumbra 3D trial. The data were presented in the late-breaking abstract session at the Society of NeuroInterventional Surgery (SNIS) 13th annual meeting in Boston, Massachusetts, by Donald Frei, MD. 

The Penumbra 3D trial was a prospective, randomized controlled noninferiority evaulation of endovascular therapies for acute ischemic stroke due to large vessel occlusion. Dr. Frei noted that although the benefits of endovascular revascularization in patients with large vessel occlusion have been established, there has not previously been detailed analysis and comparison of treatment effects using different devices. 

The trial compared the safety and efficacy of the Penumbra 3D stent retriever used in conjunction with a Penumbra aspiration device to results from a cohort using the aspiration approach alone, which Dr. Frei noted represents the first class I evidence of this kind. The primary endpoints of the trial included core lab–adjudicated angiographic revascularization and safety. A total of 198 patients were randomized at 25 centers in the United States. 

The results presented at SNIS showed noninferior revascularization rates according to the US Food and Drug Administration-defined primary effectiveness measure of thrombolysis in cerebral infarction (TICI) 2–3 in the Penumbra 3D-plus-aspiration arm compared to the aspiration-only arm (88.5% vs 85.9%). In addition, the more strictly defined revascularization measure, TICI 2b/3, showed noninferiority between the Penumbra 3D-plus-aspiration arm and the aspiration-only arm (83.9% vs 74.1%). The primary safety endpoints—device-related and procedure-related serious adverse events—were not statistically different between the two arms (P = 1.0 and P = .492, respectively).

Patients in both arms experienced similar rates of return to functional independence (modified Rankin Score = 2 at 90 days): 41.6% in the 3D-plus-aspiration arm and 48.8% in the aspiration-only arm (P = .426). The clinical outcomes were obtained without the benefit of selecting patients using imaging techniques designed to detect viable brain tissue.

"The results of the Penumbra 3D trial speak positively on the use of Penumbra’s 3D revascularization device in combination with the Penumbra system aspiration devices, as well as on the use of Penumbra system aspiration devices alone," commented Dr. Frei in the company's announcement. “The data also suggest that the revascularization rate in the Penumbra 3D-plus-aspiration-device arm and the aspiration device-only arm—83.9% and 74.1% percent, respectively—compare favorably to the 71% revascularization rate published in the HERMES meta-analysis of five major randomized controlled trials in acute ischemic stroke." Dr. Frei is the Director of NeuroInterventional Surgery at Radiology Imaging Associates/Swedish Medical Center in Englewood, Colorado, and President of SNIS.