Endologix (NSDQ:ELGX) moved to defend its AFX stent grafts after the FDA this week warned of the risk of endoleaks with the devices, which are used to treat abdominal aortic aneurysms.
The FDA added the Irvine, Calif.-based company’s The AFX with Duraply and AFX2 to last year’s warning about the AFX with Strata device, citing data showing a higher-than-expected risk of blood leakage called Type III endoleak.
The federal safety watchdog cited data from an abstract published in the Journal of the American College of Surgeons showing a 2.5% cumulative probability of additional procedures needed to treat Type III endoleaks at two years of follow-up for patients treated with AFX grafts.
The FDA acknowledged limitations in the data, given that there were 32 patients observed with AFX2, 197 with AFX with Duraply and 374 patients with AFX with Strata. The agency also noted Endologix’s ongoing Leopard trial, which is observing AAA patients randomly given either an AFX device with Duraply or an FDA-approved endovascular graft from other manufacturers. Recent data from that trial showed the cumulative probability of Type III endoleaks from AFX devices is 1%, compared to 0% from the other grafts, according to the FDA.
In an Oct. 30 letter to physicians, Endologix countered that there were no Type IIIb endoleaks reported in the Leopard trial in 111 patients implanted with the AFX2.
“[A]nd there is no clinically meaningful difference in the primary end point of aneurysm-related complications between the AFX group and the comparator grafts from Medtronic, Cook and Gore,” the company wrote.
Regarding the JACS abstract, “Our view is that 13 patients with 2-year follow-up implanted with AFX2 does not constitute an adequate sample size to draw clinically meaningful conclusions,” Endologix said, citing its own extensive data tracking operation.
“All the data sets we use are concordant and report, through the prospective analysis of nearly 65,000 patients with the AFX system, that our AFX Duraply and AFX2 Systems currently achieve patient outcomes equivalent to other contemporary commercialized endografts, when assessed on an encompassing spectrum of clinical complications. These data also support our conclusion that changes to the ePTFE manufacturing process from AFX Strata to AFX Duraply, along with the AFX IFU updates, are associated with a reduction in the occurrence of Type III endoleaks for the AFX system,” the company wrote in the letter. “As a result of our analysis of multiple data sets, including independent sources and data with active comparators, we remain confident that the AFX2 device is a safe, effective and highly competitive product when used as indicated. We will continue to work to understand and place into appropriate context results of data that become publicly available. However, we would stress that a holistic concept of safety and efficacy, which considers the strength of evidence, the sample size, data quality and an active comparator, is more appropriate when assessing endograft performance, rather than focusing on a single clinical performance outcome.”
ELGX shares are off -19.4% since the FDA announcement earlier this week, after rising 1.6% today in mid-morning trading to $2.49 apiece.
