Background

Based on 6-month data from the InVivo Study of Probable Benefit of the Neuro-Spinal Scaffold for Safety and Neurological Recovery in Patients with Complete Thoracic Spinal Cord Injury (INSPIRE) study (NCT02138110), acute implantation of an investigational bioresorbable polymer device (Neuro-Spinal Scaffold [NSS]) appeared to be safe in patients with complete thoracic spinal cord injury (SCI) and was associated with an ASIA Impairment Scale (AIS) conversion rate that exceeded historical controls.

Objective

To evaluate outcomes through 24 months postimplantation.

Methods

INSPIRE was a prospective, open-label, multicenter, single-arm study. Eligible patients had traumatic nonpenetrating SCI with a visible contusion on MRI, AIS A classification, neurological level of injury at T2-T12, and requirement for open spine surgery ≤96 hours postinjury.

Results

Nineteen patients underwent NSS implantation. Three patients had early death determined by investigators to be unrelated to the NSS or its implantation procedure. Seven of 16 evaluable patients (44%) had improvement of ≥1 AIS grade at 6 months (primary end point) to AIS B (n = 5) or AIS C (n = 2). Three patients with AIS B at 6 months had further neurological improvement to AIS C by 12 (n = 2) and 24 (n = 1) months, respectively; none have deteriorated per latest available follow-up. No unanticipated or serious adverse device effects were reported.

Conclusion

In this small group of patients with complete thoracic SCI, acute NSS implantation within the spinal cord appeared to be safe with no long-term neurological issues identified during the 24-month follow-up. Patients remain stable, with additional AIS conversions observed in some patients at 12 months and beyond. These data further support the safety and probable benefit of NSS implantation in this patient population.

Background and objectives

Traumatic spinal cord injury (SCI) remains a devastating condition with no proven effective treatment options available. In a prior single-arm study of patients with thoracic complete SCI (INSPIRE; ClinicalTrials.gov, NCT02138110), acute implantation of an investigational bioresorbable polymer scaffold (Neuro-Spinal Scaffold [NSS]) appeared to be safe through 24 months postimplantation and was associated with an American Spinal Injury Association Impairment Scale (AIS) conversion rate that exceeded historical controls. Here, we evaluated whether NSS implantation demonstrates probable benefit for safety and neurological recovery in patients with thoracic complete SCI vs standard-of-care spine surgery.

Methods

INSPIRE 2.0 was a randomized, controlled, parallel, multicenter study conducted at Level I trauma centers in the United States (ClinicalTrials.gov, NCT03762655; funded by InVivo Therapeutics Corporation). Patients with AIS grade A, thoracic (T2-T12), nonpenetrating SCI requiring spine surgery ≤7 days postinjury were randomized (1:1, computer-generated allocation) to undergo NSS implantation or spine surgery alone (control group). Patients and follow-up International Standards for Neurological Classification of SCI assessors were blinded. A predefined study success criterion required the proportion of patients with improvement of ≥1 AIS grade at 6 months postsurgery (primary endpoint) to be ≥20% higher in the NSS group than in the control group.

Results

Target enrollment was reached (N = 20) with 10 patients randomized and analyzed in each group. At 6 months postsurgery, an improvement in the AIS grade was reported in 2 NSS patients (20%; both to AIS C) and 3 control group patients (30%; to AIS B [n = 2] or AIS C [n = 1]). No serious or unanticipated adverse device effects were reported. The study was closed to further follow-up because of not meeting its primary endpoint.

Conclusion

In this small group of patients with thoracic complete (AIS A) SCI, implantation of an intraparenchymal bioresorbable scaffold did not produce probable clinical benefit. However, this study provides evidence that surgical intervention in an injured spinal cord parenchyma may be performed safely.