Fresh data from the CERUS study—the first multicentre clinical trial evaluating safety and effectiveness outcomes with the Contour neurovascular system (Cerus Endovascular)—have indicated “encouraging results” in the treatment of unruptured intracranial bifurcation aneurysms.
Reporting these results in the journal Neurosurgery, Thomas Liebig, head of the Department of Diagnostic and Interventional Neuroradiology at the Ludwig Maximilian University of Munich in Munich, Germany, and colleagues, also note that the latest Contour findings compare favourably to existing studies on intrasaccular devices—especially those involving conventional therapies for wide-neck bifurcation aneurysms (WNBAs).
The authors begin by noting that endovascular procedures have become the standard of care in certain anatomic locations and geometries, with the Contour device recently joining the Woven EndoBridge (WEB; Microvention) and LUNA-AED (Medtronic) technologies on the list of intrasaccular flow disruptors used in these procedures. However, they add, an important distinction here is that Contour is a planar braid entirely positioned at the neck of the aneurysm, while WEB and LUNA have spherical braids that fill the aneurysm dome.
The CERUS study is a single-arm, prospective, multicentre clinical trial designed to evaluate the procedural, short-term and midterm safety and effectiveness of Contour in unruptured saccular bifurcation aneurysms. In light of positive six-month follow-up results from the study, which were presented at the 2020 ABC-WIN seminar (13–17 January; Val-d’Isère, France), the device was granted European CE-mark approval in 2020.
The study was conducted at six European sites in Austria, Denmark and Germany. Inclusion criteria were as follows: untreated; 18–80 years of age; aneurysm unruptured; 2–8mm neck; and no adjunctive devices (except bailout). Primary endpoints of the CERUS study included technical success, occlusion at six months, and death or disabling stroke within 30 days and at six months, while occlusion at 12 months, instrumentation time, number of deployment attempts, and retreatment rate, were among its secondary endpoints.
Liebig and colleagues report that procedures in the study were performed under general anaesthesia on biplane angiosuites through a transfemoral approach, with a total of 34 patients (Mean age=58 years; 19 males [55.9%]) being recruited for treatment with Contour between October 2018 and July 2019.
Recapping initial procedural data, they state that technical success was achieved in 32 of these patients (94%)—while two patients in the study’s intention-to-treat group were not implanted with the Contour device and excluded from follow-up after 30 days. In 21 patients (66%), the device was implanted and detached at the first attempt and, in 11 patients (34%), it was deliberately retrieved and redeployed or replaced with a different size. Instrumentation time ranged from five to 67 minutes (mean time=19.8 minutes), they add.
The primary safety endpoint of death or disabling stroke within 30 days/at six months was met in two patients in the study’s intention-to-treat group, and in one patient in the per-protocol group. At 12 months, 30 of 32 patients in the per-protocol analysis had a modified Rankin Scale (mRS) score of zero. One patient entered into the study with an mRS score of two, and remained stable throughout, and another patient with an mRS score of zero at six months had no entry for the 12-month follow-up, Liebig and colleagues report.
Discussing these findings further, the authors note two procedural serious adverse events in the study, both of which were unrelated to Contour but instead attributed to the general risk of treatment. They also observed two treatment-related minor strokes for which symptoms were resolved at the next follow-up visit. As such, Liebig and colleagues write: “Overall, the safety profile of the Contour is acceptable and most likely comparable with other endovascular treatment options.”
Regarding efficacy outcomes, complete occlusion was seen in 14 of 32 patients (44%) at six months and 22 of 32 (69%) at 12 months. Adequate occlusion, measured as one or two on Raymond-Roy occlusion classification, was reached in 84% of patients at the last available follow-up. The authors note that these results are “comparable with multicentre trials on WEB and thus superior to those of conventional therapies for WNBAs”. In the CERUS study, one patient from the intention-to-treat group and one from the per-protocol group received additional treatment during follow-up, they add.
Liebig and colleagues also provide a number of key pieces of context in their report, including the fact that 30 patients were imaged at six months, compared to 21 at 12 months, with patients who were unavailable to perform the 12-month follow-up having their six-month occlusion status carried forward. In addition, they note that completeness of follow-up was interfered with by the COVID-19 pandemic, as some 12-month follow-up visits fell within the first lockdown period and could only be performed by remote interview.
The authors report that there was no lead-in phase for the trial—meaning none of the operators had previously used the Contour device in a patient—and patient selection was performed without interference from Cerus Endovascular. “This has to be kept in mind, especially when comparing the results with those of other studies,” they add.
The main limitations of the CERUS study, Liebig and colleagues write, are its small sample size, non-randomised nature, and the fact patients were not excluded because of poor pretreatment clinical status or partial aneurysm thrombosis. However, there was also no case selection process in place, according to the authors, which they suggest represents a more realistic scenario and might make the results reproducible outside of a study setting.
“Further systematic evaluation is warranted in light of possible future iterations of the study device [Contour] and to better understand its full potential,” they conclude.