Data Presented From InspireMD's MASTER and CARENET Trials

December 15, 2014—InspireMD, Inc. announced that results from two clinical trials were presented at the International Conference for Innovations in Cardiovascular Systems meeting in Tel Aviv, Israel. Principal investigator Gregg Stone, MD, presented results from the MASTER II trial of the company’s MGuard Prime coronary embolic protection system (EPS) device. Also, Piotr Musialek, MD, coprincipal investigator of the CARENET (Carotid Embolic Protection Study Using Micronet) trial, presented ipsilateral diffusion-weighted magnetic resonance imaging (DW-MRI) results for the CGuard EPS.

MGuard EPS and CGuard EPS are CE Mark approved. In the United States, the devices are not approved for sale by the US Food and Drug Administration (FDA).

According to InspireMD, the data presented by Dr. Stone included 30-day results on the 310 patients enrolled in MASTER II, as well as pooled data from MASTER II and the 433-patient MASTER I trial completed and published in 2012.

MASTER II was a global clinical trial conducted under an FDA investigational device exemption that is intended for United States registration of the MGuard Prime coronary EPS for use in patients presenting with ST-segment elevated myocardial infarction (STEMI). The trial was designed to show superiority of ST-segment resolution 60 to 90 minutes postprocedure, as well as noninferiority in all-cause death or recurrent target vessel myocardial infarction.

The MASTER II trial was suspended in October 2014 as a result of a corporate shift in strategy to a next-generation MGuard drug-eluting stent platform. The trial was halted well short of the planned enrollment of 1,114 patients. However, the company elected to unblind the data and present the results on behalf of the study investigators.

Although MASTER I achieved the primary endpoint of superiority in ST-segment resolution (57.8% vs 44.7%; P =.008), MASTER II did not show a difference in ST-segment resolution between MGuard and control stents (FDA-approved bare metal or drug-eluting stents) (56.9% vs 59.3%; P = .68). Pooled data between MASTER I and MASTER II for ST-segment resolution continued to favor MGuard compared with the control group (57.5% vs 50.7%; P = .07).

The company noted that 30-day mortality results for the MGuard in the MASTER II trial remained low (0.6% vs 1.9%; P = .62), consistent with all previous MGuard trials and registries, and the overall rate of major adverse cardiac events was favorable for MGuard (2.6% vs. 4.5%; P = .36). Pooled mortality data for MASTER I and II showed a statistically significant reduction in mortality with MGuard (0.3% vs 1.9%; P = .04). Infarct size showed a positive trend for MGuard in MASTER II (mean, 22.6% vs 27.48%; P = .16), as well as in the pooled analysis (mean, 18.8% vs 22.24%; P = .26).

In the company’s press release, Dr. Stone commented, “The data from MASTER II supports further clinical evaluation of the MGuard Prime EPS. While the number of patients enrolled in MASTER II were not powered for any endpoints, it was encouraging to see the significant difference in mortality with the pooled data, with other indicators of improved reperfusion success with the MGuard technology. We look forward to the development of a drug-eluting stent version of MGuard in the near future to continue a pivotal clinical evaluation of the MicroNet embolic protection system.”

As summarized by InspireMD, the CARENET trial recruited 30 patients and completed enrollment in July. In the data presented by Prof. Musialek, the CGuard demonstrated exceptional safety and efficacy with 0% major adverse cardiac or cerebrovascular events (death, stroke, or myocardial infarction) at 30 days. Additionally, the incidence of new ischemic ipsilateral lesions as assessed by DW-MRI after carotid artery stenting was 37%, a reduction of approximately 50% when compared to published historical control groups of nonmesh-covered carotid stents.

The CARENET trial also reported an average lesion volume per patient that was 10 times smaller than historical control groups. The reduction in both the incidence and volume of new ischemic lesions indicates therapeutic benefits of the MicroNet technology and that the benefits of using this device may extend beyond the acute procedural period, stated the company.