The Food and Drug Administration placed a clinical hold on new patient implants in Neuralink's PRIME study following complications reported in connection with the second participant, according to two people familiar with the matter.
The second participant's implant is believed to have shifted position in the weeks following surgery, a complication referred to as device migration, which reduced the device's effectiveness significantly. Neuralink had not publicly disclosed the second participant's outcomes, and when asked directly about the FDA hold, the company neither confirmed nor denied it.
Device migration is a recognized risk in implantable neural devices. The first participant in the PRIME study reported consistent neural signal and expanding use of the device. The divergence in outcomes between the two participants raised questions, according to people familiar with the FDA's review, about whether migration represents an isolated event or a systemic design issue.
A clinical hold prevents Neuralink from implanting new participants until the FDA lifts the restriction. The hold does not affect participants already enrolled, who may continue to use their devices.
Neuralink declined to confirm or deny the clinical hold when contacted and did not respond to specific questions about the second participant's reported complications.