Synchron Halts Stentrode Brain Implant Trials Over Faulty Lead Cable

Synchron has paused enrollment in clinical trials of its wireless second-generation Stentrode brain implant after the device underperformed in its first participants, Wired reported on Thursday. The Brooklyn-based startup, valued at close to $1 billion, says the problem lies in the lead — the cable that carries signals from the Stentrode to the implanted electronics — and that the pause was voluntary, not ordered by the FDA.

The company told Wired it stopped enrollment "after identifying a performance issue involving the lead." In a statement, Synchron said: "The issue does not involve the Stentrode itself and no safety issues related to the device have been identified. The pause was a company decision, not an FDA-directed action." Rather than fix the cable alone, Synchron will upgrade the entire Stentrode system and resume enrollment only when the new hardware is ready. The takeaway: a component as small as a cable has stalled the whole trial program.

What do the trial registries show?

ClinicalTrials.gov records now confirm the halt across three studies:

• The 10-person US INTENT early feasibility study, listed as active but not recruiting as of a Nov. 5 update.
• The 10-person Australian FOCUS study, switched to the same status on Nov. 6.
• The Canadian FOCUS study at two Toronto hospitals, marked terminated for "insufficient recruitment" the same day, after enrolling just one participant.

INTENT began in May and planned to enroll about 10 people across five sites: Mayo Clinic in Jacksonville, the University at Buffalo, Mount Sinai in New York, UPMC in Pittsburgh and UT Southwestern in Dallas. Two of the five US sites confirmed to Wired that recruitment is on hold. These early studies are meant to lead to a larger pivotal trial, which the FDA requires before it can approve the device for sale.

Why the Stentrode design matters

The Stentrode is a stent-like mesh threaded up through the jugular vein to rest over the brain's motor cortex, so it requires no open brain surgery. Ten volunteers in the US and Australia received the first-generation version, which connected through a wire on the chest. They used it to text, email, shop and bank online, and to control an iPad, Apple Vision Pro and Amazon Alexa. The second-generation device carries fewer electrodes and connects wirelessly over Bluetooth.

Chief executive Tom Oxley said the company still has "strong confidence" the device could become a first-line therapy. Synchron has brought lead design and manufacturing in-house to address the failure.

What does the restructuring change?

Synchron is cutting jobs in New York and building a San Diego team, with about a dozen openings for electrical and mechanical engineers, chip designers and materials scientists. That team will build the upgraded lead and Stentrode, plus an unannounced device the company says will go "beyond the blood vessels altogether."

The funding race around brain-computer interfaces is intensifying. Synchron raised $200 million last fall at a valuation near $1 billion, with backing from Khosla Ventures and the venture arms of Bill Gates and Jeff Bezos. Neuralink, its chief rival, was reportedly valued as high as $42 billion in secondary trading this summer. Merge Labs, co-founded by OpenAI's Sam Altman, launched in January with $252 million.

Setbacks have hit competitors too. In 2024, threads in Neuralink's first patient implant retracted from the brain, and the company restored cursor control only by rewriting its recording software. For Synchron, the path forward now depends on how quickly the San Diego engineering team can deliver a lead that survives long-term implantation and clear the way to the pivotal trial.