StemCells has enrolled its first subjects in cohort 2 of its phase II Pathway study. The study is designed to assess the efficacy of the company’s proprietary HuCNS-SC platform technology (purified human neural stem cells) for the treatment of cervical spinal cord injury. Cohort 2 will enrol 40 patients and forms the single-blinded controlled arm of the phase II study. The primary efficacy outcome being tested in cohort 2 is the change in motor strength of the various muscle groups in the upper extremities innervated by the cervical spinal cord.
The Pathway study is the first clinical trial designed to evaluate both the safety and efficacy of human neural stem cells transplanted into the spinal cord of patients with cervical spinal cord injury. The trial has three cohorts. The primary cohort is cohort 2 which is being conducted as a randomised, controlled, single-blind cohort with efficacy primarily measured by assessing motor function according to the International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI). The trial will follow the participants for one year and will enrol up to 52 subjects.
Cohort 1 of the Pathway study is an open-label, HuCNS-SC dose-escalation arm involving six patients. Safety data from all six subjects was reviewed by an independent data monitoring committee and approval was provided to commence with cohort 2. No safety or tolerability issues were seen at any of the dosing levels. The six-month outcome from cohort 1 will be disclosed as interim data later this year.
Cohort 3 is an optional open label cohort targeted to enrol six patients. This cohort is designed to assess safety and preliminary efficacy in patients with less severe injuries (AIS C).
“The initiation of Cohort 2 begins the next phase of our clinical efforts towards a potential breakthrough therapy for spinal cord injury,” said Stephen Huhn, vice president, Clinical Research and chief medical officer at StemCells. “This is the first blinded, controlled clinical trial to be conducted using human neural stem cells. The goal of this proof-of-concept study is to demonstrate the potential efficacy of our cells as a treatment for victims of spinal cord injury. We currently have seven sites enrolling patients and expect to reach a total of fourteen active North American sites by year end. Conducting a multicentre study on this scale should allow us to efficiently enrol the study.”
The company completed enrolment and dosing in its open-label phase I/II study in thoracic spinal cord injury in April 2014 and has reported top-line results. Sustained post-transplant gains in sensory function were demonstrated in seven of the twelve patients. Two patients in the phase I/II study converted from a complete injury (AIS A) to an incomplete injury (AIS B). The final results also continue to confirm the favourable safety profile of the cells and the surgical procedure.