FDA denies NeuroOne's bid to extend brain-monitoring electrode use past 24 hours

When NeuroOne Medical Technologies racked up its second FDA clearance last fall for its stereoelectroencephalography (sEEG) electrode, the company said its immediate priority—even before beginning the commercial launch—was to persuade the FDA to expand its indication for the device.

Unfortunately, eight months later, that plan has yet to come to fruition, but not for lack of trying. NeuroOne announced this week that the agency recently sent a letter denying its request to extend the electrode’s wear period to a maximum of 30 days.

The Evo sEEG electrode is placed underneath the surface of the brain in a minimally invasive procedure. From there, it can record, monitor and stimulate brain signals in patients with neurological conditions like Parkinson’s disease and epilepsy.

In the May 13 letter, the FDA upheld its initial decision to limit the Evo sEEG system’s use to just 24 hours at a time, noting that the company’s supporting evidence failed to prove that the device was substantially equivalent to other electrodes that have been cleared for longer wear periods.

NeuroOne can try again, however. The FDA specifically asked that this time around, the company provides new evidence related to the device’s potential subacute toxicity; NeuroOne said it has already begun gathering that data.

The follow-up “special” 510(k) application will undergo a faster processing time: within 30 days, compared to the 90-day window for traditional 510(k) submissions. The Minnesota-based company said it’s aiming to turn in the new evidence to the FDA by August of this year.

“While the appeal decision is disappointing, we remain optimistic that the current product design and materials will successfully demonstrate substantial equivalence at the conclusion on the ongoing subacute toxicity test,” said CEO Dave Rosa. “Once completed, we intend to submit the new test data results to the FDA while referencing the previous 510(k) submission.”

In the meantime, Rosa said, “the company will immediately explore the opportunity to market the device through Zimmer Biomet for intraoperative use to gain product clinical experience while we progress with the re-submission to the FDA.”

NeuroOne already offers a longer-lasting electrode: the Evo cortical electrode, a thin, flexible strip that’s placed on the cortical surface of the brain to track neurological signals and stimulate nerves. It was cleared by the FDA in November 2019, complete with a 30-day indication.

Zimmer Biomet holds the exclusive global rights to distribute both Evo electrodes, thanks to a licensing agreement it struck with NeuroOne in mid-2020. They didn’t disclose the financial terms of the deal, but noted that NeuroOne would be eligible to earn milestone payouts on top of an upfront payment if it reached certain commercial goals, the first of which it reached in early 2021.