Synchron has paused enrollment in clinical trials of its second-generation brain implant after the device did not perform as expected in initial participants, WIRED has learned. The Brooklyn-based startup, a competitor to Elon Musk's Neuralink, is also restructuring, cutting jobs and reducing its presence in New York while expanding a team in San Diego to develop an entirely new device.
The company's Stentrode is a stent-like mesh tube inserted into the jugular vein at the base of the neck and guided by catheter to rest atop the brain's motor cortex, an approach Synchron has promoted as minimally invasive because the device does not sit in the brain or require brain surgery. Ten volunteers in the US and Australia received the first-generation device, which connected through an external wire on the user's chest, and used it to send emails, text, browse the internet, and handle online shopping and banking, as well as to control an Amazon Alexa, Apple's iPad and the Vision Pro. The second-generation version has fewer electrodes and is fully wireless, connecting via Bluetooth.
Synchron launched a multisite trial of the newer Stentrode in the US earlier this spring, with sister sites in Australia and Canada, and some participants have already received implants. Those sites recently stopped enrolling because the device is not working as intended, according to sources familiar with the trials who asked not to be named. In a statement, Synchron said it voluntarily paused enrollment after identifying a performance issue involving the lead, the cable that carries signals from the Stentrode to the implanted electronics, and that no safety issues related to the device had been identified. The company said the pause was its own decision and not an FDA-directed action, and that it has moved lead design and manufacturing in-house.
Rather than repair the lead alone, Synchron said it is upgrading the entire Stentrode system and will resume enrollment once the hardware upgrades are finished. The company said it will continue supporting participants with Stentrode devices for their lifetime. Two of the five US trial sites WIRED reached confirmed recruitment is on hold; a coordinator at one site said the pause was not safety-related and stemmed from Synchron reviewing the device to confirm it is getting the readouts it seeks. The trials are key to advancing the Stentrode into a larger pivotal trial needed for FDA marketing approval. CEO Tom Oxley said the company retains strong confidence that the device could become a first-line therapy.
Synchron's website and LinkedIn page list about a dozen openings in San Diego, including electrical and mechanical engineers, microchip designers and materials scientists. That team will design and manufacture the upgraded lead and Stentrode along with a separate, unrevealed device that the company says will go beyond the blood vessels altogether; Oxley previously told WIRED the company planned a device reaching multiple brain regions at once, which could enable more complex and natural functions than moving a cursor or clicking a mouse.
Synchron was estimated at a valuation of nearly $1 billion after closing a $200 million funding round last fall, backed by Khosla Ventures and the venture firms of Bill Gates and Jeff Bezos. Neuralink was reportedly valued as high as $42 billion in secondary market transactions as of this summer, and in 2024 several of the wires on its implant came out of the brain of its first volunteer, Noland Arbaugh, causing a loss of cursor control that the company restored by modifying its recording algorithm. Merge Labs, cofounded by OpenAI CEO Sam Altman, emerged from stealth in January with $252 million in funding, some from OpenAI, and the two companies are collaborating on AI models. Synchron's setback shows how far the field must go before these experimental systems are commercially available to patients.
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