InVivo Therapeutics (NSDQ:NVIV) said today it is temporarily suspending enrollment in its Inspire trial of its neuro-spinal scaffold after its most recent patient, implanted last month, passed away suddenly following hospital discharge.

While the death was deemed to be unrelated to the neuro-spinal scaffold or the implantation procedure, the company said it was initiating a temporary enrollment halt while it discusses possible patient enrollment criteria changes with the FDA.

Due to the enrollment halt, Cambridge, Mass.-based InVivo said it expects it will complete enrollment for the trial during the 1st half of 2018, with a slated submission seeking humanitarian device exemption from the FDA during the 2nd half of 2018.

“Our thoughts and condolences are with the patient’s loved ones at this difficult time. We remain committed to monitoring carefully all aspects of the Inspire study to ensure the ongoing safety of subjects. Regarding the enrollment halt, we are working toward an expeditious resolution. Based on the compelling clinical results to date, particularly the 2 most recent AIS conversions, we hope to reopen enrollment as soon as possible,” CEO Mark Perrin said in a press release.

The company’s neuro-spinal scaffold is a novel, biodegradable device designed to be surgically implanted following acute spinal cord injuries to act as a physical substrate for nerve sprouting.

InVivo updated on patient conversions within the trial, saying that 1 patient had improved from a complete AIS A SCI to motor complete AIS C SCI at a 1 month visit, while a 2nd patient improved from a complete AIS A SCI to sensory incomplete AIS B SCI at their 6-month visit. A total of 6 of 11 patients in the trial have had an AIS grade improvement at the 6-month primary endpoint visit, the company said.

A patient who had shown to have initially converted from a complete AIS A SCI to sensory incomplete AIS B SCI at 2 months reverted back to AIS A at 3 months, but then was deemed to have converted from AIS A to AIS B at 6 months, the company said.

“This patient has demonstrated motor improvements from baseline assessments, and the conversion to AIS B at the 6-month visit is encouraging,” site principal investigator Dr. Travis Dumont of Banner – Univeristy Medical Center Tucson said in a prepared statement.

A separate patient was shown to have converted from AIS A SCI to motor incomplete AIS C SCI between their discharge from the hospital and 1-month visit. The company said that the patient was assessed to have a T6 neurological level of injury, and that they were the 2nd to have reached AIS C motor incomplete classification at the 1-month evaluation.

“A conversion to AIS C at one month for a patient with a T6 level of injury is rare. I look forward to continuing to track the patient’s progress and hope that the patient continues to show signs of neurological recovery,” site principal investigator Dr. Terrence Julien of Pittsburgh, Penn.’s Allegheny General Hospital said in a prepared statement.

Earlier this month, InVivo said it added Stanford Medicine as the 34th clinical site in the Inspire study of its neuro-spinal scaffold.