Study protocol for the G-SPIRIT trial: a randomised, placebo-controlled, double-blinded phase III trial of granulocyte colony-stimulating factor-mediated neuroprotection for acute spinal cord injury

Clinical application and potential pluripotent effects of hepatocyte growth factor in spinal cord injury regeneration

INTRODUCTION

Spinal cord injury (SCI) is a condition in which the spinal cord parenchyma is damaged by various factors. The mammalian central nervous system has been considered unable to regenerate once damaged, but recent progress in basic research has gradually revealed that injured neural cells can indeed regenerate. Drug therapy using novel agents is being actively investigated as a new treatment for SCI. One notable treatment method is regeneration therapy using hepatocyte growth factors (HGF).

AREA COVERED

HGF has pluripotent neuroregenerative actions, as indicated by its neuroprotective and regenerative effects on the microenvironment and damaged cells, respectively. This review examines these effects in various phases of SCI, from basic research to clinical studies, and the application of this treatment to other diseases.

EXPERT OPINION

In regenerative medicine for SCI, drug therapies have tended to be more likely to be developed compared to cell replacement treatment. Nevertheless, there are still challenges to be addressed for these clinical applications due to a wide variety of pathology and animal experimental models of basic study, but HGF could be an effective treatment for SCI with expanded application.

Clinical Trials Targeting Secondary Damage after Traumatic Spinal Cord Injury

Spinal cord injury (SCI) often causes loss of sensory and motor function resulting in a significant reduction in quality of life for patients. Currently, no therapies are available that can repair spinal cord tissue. After the primary SCI, an acute inflammatory response induces further tissue damage in a process known as secondary injury. Targeting secondary injury to prevent additional tissue damage during the acute and subacute phases of SCI represents a promising strategy to improve patient outcomes. Here, we review clinical trials of neuroprotective therapeutics expected to mitigate secondary injury, focusing primarily on those in the last decade. The strategies discussed are broadly categorized as acute-phase procedural/surgical interventions, systemically delivered pharmacological agents, and cell-based therapies. In addition, we summarize the potential for combinatorial therapies and considerations.

The immune microenvironment and tissue engineering strategies for spinal cord regeneration

Regeneration of neural tissue is limited following spinal cord injury (SCI). Successful regeneration of injured nerves requires the intrinsic regenerative capability of the neurons and a suitable microenvironment. However, the local microenvironment is damaged, including insufficient intraneural vascularization, prolonged immune responses, overactive immune responses, dysregulated bioenergetic metabolism and terminated bioelectrical conduction. Among them, the immune microenvironment formed by immune cells and cytokines plays a dual role in inflammation and regeneration. Few studies have focused on the role of the immune microenvironment in spinal cord regeneration. Here, we summarize those findings involving various immune cells (neutrophils, monocytes, microglia and T lymphocytes) after SCI. The pathological changes that occur in the local microenvironment and the function of immune cells are described. We also summarize and discuss the current strategies for treating SCI with tissue-engineered biomaterials from the perspective of the immune microenvironment.

Human Umbilical Cord Mesenchymal Stem Cells to Treat Neuromyelitis Optica Spectrum Disorder (hUC-MSC-NMOSD): A Study Protocol for a Prospective, Multicenter, Randomized, Placebo-Controlled Clinical Trial

Background

Neuromyelitis Optica spectrum disorder (NMOSD) is severe relapsing and disabling autoimmune disease of the central nervous system. Its optimal first-line treatment to reduce relapse rate and ameliorate neurological disability remains unclear. We will conduct a prospective, multicenter, randomized, placebo-controlled clinical trial to study the safety and effectiveness of human umbilical cord mesenchymal stem cells (hUC-MSCs) in treating NMOSD.

Methods

The trial is planned to recruit 430 AQP4-IgG seropositive NMOSD patients. It consists of three consecutive stages. The first stage will be carried out in the leading center only and aims to evaluate the safety of hUC-MSCs. Patients will be treated with three different doses of hUC-MSCs: 1, 2, or 5 × 10⁶ MSC/kg·weight for the low-, medium-, and high-dose group, respectively. The second and third stages will be carried out in six centers. The second stage aims to find the optimal dosage. Patients will be 1:1:1:1 randomized into the low-, medium-, high-dose group and the controlled group. The third stage aims to evaluate the effectiveness. Patients will be 1:1 randomized into the optimal dose and the controlled group. The primary endpoint is the first recurrent time and secondary endpoints are the recurrent times, EDSS scores, MRI lesion numbers, OSIS scores, Hauser walking index, and SF-36 scores. Endpoint events and side effects will be evaluated every 3 months for 2 years.

Discussion

Although hUC-MSC has shown promising treatment effects of NMOSD in preclinical studies, there is still a lack of well-designed clinical trials to evaluate the safety and effectiveness of hUC-MSC among NMOSD patients. As far as we know, this trial will be the first one to systematically demonstrate the clinical safety and efficacy of hUC-MSC in treating NMOSD and might be able to determine the optimal dose of hUC-MSC for NMOSD patients.

Trial registration

The study was registered with the Chinese Clinical Trial Registry (CHICTR.org.cn) on 2 March 2016 (registration No. ChiCTR-INR-16008037), and the revised trial protocol (Protocol version 1.2.1) was released on 16 March 2020.

First-in-human clinical trial of transplantation of iPSC-derived NS/PCs in subacute complete spinal cord injury: Study protocol

Introduction

Our group has conducted extensive basic and preclinical studies of the use of human induced pluripotent cell (iPSC)-derived neural stem/progenitor cell (hiPSC-NS/PC) grafts in models of spinal cord injury (SCI). Evidence from animal experiments suggests this approach is safe and effective. We are preparing to initiate a first-in-human clinical study of hiPSC-NS/PC transplantation in subacute SCI.

Setting

NS/PCs were prepared at a Good Manufacturing Practice-grade cell processing facility at Osaka National Hospital using a clinical-grade integration-free hiPSC line established by the iPSC Stock Project organized by the Kyoto University Center for iPS Cell Research and Application. After performing all quality checks, the long-term safety and efficacy of cells were confirmed using immunodeficient mouse models.

Methods

The forthcoming clinical study uses an open-label, single-arm design. The initial follow-up period is 1 year. The primary objective is to assess the safety of hiPSC-NS/PC transplantation in patients with subacute SCI. The secondary objective is to obtain preliminary evidence of its impact on neurological function and quality-of-life outcomes. Four patients with C3/4-Th10 level, complete subacute (within 24 days post-injury) SCI will be recruited. After obtaining consent, cryopreserved cells will be thawed and prepared following a multi-step process including treatment with a γ-secretase inhibitor to promote cell differentiation. A total of 2 × 10⁶ cells will be transplanted into the injured spinal cord parenchyma 14–28 days post-injury. Patients will also receive transient immunosuppression. This study protocol has been reviewed and approved by the Certified Committee for Regenerative Medicine and the Japanese Ministry of Health, Labor and Welfare (University Hospital Medical Information Network Clinical Trials Registry [UMIN-CTR] number, UMIN000035074; Japan Registry of Clinical Trials [jRCT] number, jRCTa031190228).

Discussion/conclusion

We plan to start recruiting a patient as soon as the COVID-19 epidemic subsides. The primary focus of this clinical study is safety, and the number of transplanted cells may be too low to confirm efficacy. After confirming safety, a dose-escalation study is planned.

•

A first-in-human clinical study for spinal cord injury using iPSC-derived cells is about to begin.

•

The primary objective is to assess the safety of human iPSC-derived neural stem/progenitor cells.

•

Further clinical trials are expected to be conducted to statistically assess efficacy.

A review of emerging neuroprotective and neuroregenerative therapies in traumatic spinal cord injury

Traumatic spinal cord injuries (SCIs) have far-reaching physical, social, and financial consequences. While medical advancements have improved supportive therapeutic measures for SCI patients, no effective neuroregenerative therapeutic options exist to date. Instead, the paradigm of SCI therapy is inevitably directed towards damage control rather than the restoration of a state of functional independence. Facing a continuous increase in the prevalence of spinal cord injured patients, neuroprotective and neuroregenerative strategies have earned tremendous scientific interest. This review intends to provide a robust summary of the most promising neuroprotective and neuroregenerative therapies currently under investigation. While we highlight encouraging neuroprotective strategies as well, the focus of this review lies on neuroregenerative therapies, including neuropharmacological and cell-based approaches. We finally point to the exciting investigational areas of biomaterial scaffolds and neuromodulation therapies.

Randomized trial of granulocyte colony-stimulating factor for spinal cord injury

Attenuation of the secondary injury of spinal cord injury (SCI) can suppress the spread of spinal cord tissue damage, possibly resulting in spinal cord sparing that can improve functional prognoses. Granulocyte colony-stimulating factor (G-CSF) is a haematological cytokine commonly used to treat neutropenia. Previous reports have shown that G-CSF promotes functional recovery in rodent models of SCI. Based on preclinical results, we conducted early phase clinical trials, showing safety/feasibility and suggestive efficacy. These lines of evidence demonstrate that G-CSF might have therapeutic benefits for acute SCI in humans. To confirm this efficacy and to obtain strong evidence for pharmaceutical approval of G-CSF therapy for SCI, we conducted a phase 3 clinical trial designed as a prospective, randomized, double-blinded and placebo-controlled comparative trial. The current trial included cervical SCI [severity of American Spinal Injury Association (ASIA) Impairment Scale (AIS) B or C] within 48 h after injury. Patients are randomly assigned to G-CSF and placebo groups. The G-CSF group was administered 400 μg/m²/day × 5 days of G-CSF in normal saline via intravenous infusion for five consecutive days. The placebo group was similarly administered a placebo. Allocation was concealed between blinded evaluators of efficacy/safety and those for laboratory data, as G-CSF markedly increases white blood cell counts that can reveal patient treatment. Efficacy and safety were evaluated by blinded observer. Our primary end point was changes in ASIA motor scores from baseline to 3 months after drug administration. Each group includes 44 patients (88 total patients). Our protocol was approved by the Pharmaceuticals and Medical Device Agency in Japan and this trial is funded by the Center for Clinical Trials, Japan Medical Association. There was no significant difference in the primary end point between the G-CSF and the placebo control groups. In contrast, one of the secondary end points showed that the ASIA motor score 6 months (P = 0.062) and 1 year (P = 0.073) after drug administration tend to be higher in the G-CSF group compared with the placebo control group. The present trial failed to show a significant effect of G-CSF in primary end point.

Serum C-reactive protein is an early, simple and inexpensive prognostic marker for the progression of intramedullary lesion on magnetic resonance imaging from acute to subacute stage in patients with spinal cord injury

STUDY DESIGN

Retrospective chart audit.

OBJECTIVES

This study aimed to identify conventional routine blood testing biomarkers associated with the progression of intramedullary injured area in patients with spinal cord injury (SCI).

SETTING

A spinal cord injury center in Hokkaido, Japan.

METHODS

We retrospectively reviewed 71 consecutive adults with acute SCI who were admitted within 24 h after injury and diagnosed as American Spinal Injury Association Impairment Scale Grade A or B at admission. Participants were divided into the progression (P group) and no progression group (NP group) based on the change of the hyperintense signal abnormality in the spinal cord on magnetic resonance imaging from the time of admission to 4 weeks after injury. Individual characteristics and blood testing data obtained in the first 4 weeks after injury were compared between groups.

RESULTS

The P and NP groups were comprised of 16 and 55 participants, respectively. In univariate analyses, white blood cell (WBC) count on day 3 was significantly higher in group P than group NP (P = 0.021), as was serum C-reactive protein (CRP) level on day 3 (P = 0.015) and day 7 (P = 0.047). Multivariable analysis identified serum CRP level on day 3 as a significant independent prognostic factor for the progression of secondary SCI (OR, 1.138; 95% confidence interval, 1.01-1.28; P = 0.034).

CONCLUSIONS

Serum CRP level on day 3 after injury was a good predictor for the progression of intramedullary signal intensity change on MRI from acute to subacute stage in patients with SCI.

Traumatic Spinal Cord Disorders: Current Topics and Future Directions

Traumatic spinal cord injury (tSCI) is a life-changing and potentially overwhelming event. The sudden disruption of the spinal cord's integrity necessitates rapid attention at a specialized medical center, and involves a multilateral collaboration between neurologists, spine surgeons, critical care physicians, and trauma specialists. Even with care under ideal conditions, many tSCI patients have significant disability that persists for the rest of their lives. However, recently, we have seen a proliferation in clinical and translational trials that offer the promise that new treatments may be available soon.

Pharmacological management of secondary spinal cord injury

Introduction: Secondary spinal cord injury (SCI) sets on immediately after trauma and, despite prompt treatment, may become chronic. SCI is a complex condition and presents numerous challenges to patients and physicians alike, also considering the lack of an approved pharmacological therapy.Areas covered: This review describes the pathophysiological mechanisms leading to secondary SCI to highlight possible targets for pharmacological therapy. Furthermore, an extensive search of the literature on different databases (PubMed, Google scholar, Embase, and Scopus) and of the current clinical trials (clinicaltrials.gov) was performed to investigate the current outlook for the pharmacological management of SCI. Only drugs with performed or ongoing clinical trials were considered.Expert opinion: Pharmacological therapy aims to improve motor and sensory function in patients. Overall, drugs are divided into neuroprotective compounds, which aim to limit the damage induced by the pro-inflammatory and pro-apoptotic milieu of SCI, and neuroregenerative drugs, which induce neuronal and axonal regrowth. While many compounds have been trialed with promising results, none has yet completed a stage III trial and has been approved for the pharmacological management of SCI.

Granulocyte colony-stimulating factor in traumatic spinal cord injury

Granulocyte colony-stimulating factor (G-CSF) is a cytokine used in pharmaceutical preparations for the treatment of chemotherapy-induced neutropenia. Evidence from experimental studies indicates that G-CSF exerts relevant activities in the central nervous system (CNS) in particular after lesions. In acute, subacute, and chronic CNS lesions, G-CSF appears to have strong anti-inflammatory, antiapoptotic, antioxidative, myelin-protective, and axon-regenerative activities. Additional effects result in the stimulation of angiogenesis and neurogenesis as well as in bone marrow stem cell mobilization to the CNS. There are emerging preclinical and clinical data indicating that G-CSF is a safe and effective drug for the treatment of acute and chronic traumatic spinal cord injury (tSCI), which we summarize in this review.

Pharmacologic and Regenerative Cell Therapy for Spinal Cord Injury: WFNS Spine Committee Recommendations

This is a review article examining the pharmacologic and regenerative cell therapy for spinal cord injury. A literature search during last 10 years were conducted using key words. Case reports, experimental (nonhuman) studies, papers other than English language were excluded. Up-to-date information on the pharmacologic and regenerative cell therapy for spinal cord injury was reviewed and statements were produced to reach a consensus in 2 separate consensus meeting of WFNS Spine Committee. The statements were voted and reached a consensus using Delphi method. Pharmacologic and regenerative cell therapy for spinal cord injury have long been an interest of many experimental and clinical researches. Clinical studies with methylpredinisolone have not shown clear cut benefit. Other drugs such as Rho inhibitor, minocycline, riluzole, granulocyte colony-stimulating factor have also been tried without significant benefits. Regenerative cell therapy using different types of stem cells, different inoculation techniques, and scaffolds have undergone many trials highlighting the efficacies of cells and their limitations. This review article summarizes the current knowledge on pharmacologic and regenerative cell therapy for spinal cord injury. Unfortunately, there is a need for further experimental and human trials to recommend effective pharmacologic and regenerative cell therapy.

Repeated subarachnoid administrations of allogeneic human umbilical cord mesenchymal stem cells for spinal cord injury: a phase 1/2 pilot study

BACKGROUND AIMS

Stem cell transplantation is a potential treatment for intractable spinal cord injury (SCI), and allogeneic human umbilical cord mesenchymal stem cells (hUC-MSCs) are a promising candidate because of the advantages of immune privilege, paracrine effect, immunomodulatory function, convenient collection procedure and little ethical concern, and there is an urgent need to develop a safe and effective protocol regarding their clinical application.

METHODS

A prospective, single-center, single-arm study in which subjects received four subarachnoid transplantations of hUC-MSCs (1 × 10⁶ cells/kg) monthly and were seen in follow-up four times (1, 3, 6 and 12 months after final administration) was conducted. At each scheduled time point, safety and efficacy indicators were collected and analyzed accordingly. Adverse events (AEs) were used as a safety indicator. American Spinal Injury Association (ASIA) and SCI Functional Rating Scale of the International Association of Neurorestoratology (IANR-SCIFRS) total scores at the fourth follow-up were determined as primary efficacy outcomes, whereas these two indicators at the remaining time points as well as scores of pinprick, light touch, motor and sphincter, muscle spasticity and spasm, autonomic system, bladder and bowel functions, residual urine volume (RUV) and magnetic resonance imaging (MRI) were secondary efficacy outcomes. Subgroup analysis of primary efficacy indicators was also performed.

RESULTS

Safety and efficacy assessments were performed on 102 and 41 subjects, respectively. Mild AEs involving fever (14.1%), headache (4.2%), transient increase in muscle tension (1.6%) and dizziness (1.3%) were observed following hUC-MSC transplantation and resolved thoroughly after conservative treatments. There was no serious AE. ASIA and IANR-SCIFRS total scores revealed statistical increases when compared with the baselines at different time points during the study, mainly reflected in the improvement of pinprick, light touch, motor and sphincter scores. Moreover, subjects showed a continuous and remarkable decrease in muscle spasticity. Regarding muscle spasm, autonomic system, bladder and bowel functions, RUV and MRI, data/imaging at final follow-up showed significant improvements compared with those at first collection. Subgroup analysis found that hUC-MSC transplantation improved neurological functions regardless of injury characteristics, including level, severity and chronicity.

CONCLUSIONS

The authors' present protocol demonstrates that intrathecal administration of' allogeneic hUC-MSCs at a dose of 10⁶ cells/kg once a month for 4 months is safe and effective and leads to significant improvement in neurological dysfunction and recovery of quality of life.

Human umbilical cord mesenchymal stem cells to treat spinal cord injury in the early chronic phase: study protocol for a prospective, multicenter, randomized, placebo-controlled, single-blinded clinical trial

Human umbilical cord mesenchymal stem cells (hUC-MSCs) support revascularization, inhibition of inflammation, regulation of apoptosis, and promotion of the release of beneficial factors. Thus, they are regarded as a promising candidate for the treatment of intractable spinal cord injury (SCI). Clinical studies on patients with early chronic SCI (from 2 months to 1 year post-injury), which is clinically common, are rare; therefore, we will conduct a prospective, multicenter, randomized, placebo-controlled, single-blinded clinical trial at the Third Affiliated Hospital of Sun Yat-sen University, West China Hospital of Sichuan University, and Shanghai East Hospital, Tongji University School of Medicine, China. The trial plans to recruit 66 early chronic SCI patients. Eligible patients will undergo randomization at a 2:1 ratio to two arms: the observation group and the control group. Subjects in the observation group will receive four intrathecal transplantations of stem cells, with a dosage of 1 × 10⁶/kg, at one calendar month intervals. Subjects in the control group will receive intrathecal administrations of 10 mL sterile normal saline in place of the stem cell transplantations. Clinical safety will be assessed by the analysis of adverse events and laboratory tests. The American Spinal Injury Association (ASIA) total score will be the primary efficacy endpoint, and the secondary efficacy outcomes will be the following: ASIA impairment scale, International Association of Neural Restoration-Spinal Cord Injury Functional Rating Scale, muscle tension, electromyogram, cortical motor and cortical sensory evoked potentials, residual urine volume, magnetic resonance imaging-diffusion tensor imaging, T cell subtypes in serum, neurotrophic factors and inflammatory factors in both serum and cerebrospinal fluid. All evaluations will be performed at 1, 3, 6, and 12 months following the final intrathecal administration. During the entire study procedure, all adverse events will be reported as soon as they are noted. This trial is designed to evaluate the clinical safety and efficacy of subarachnoid transplantation of hUC-MSCs to treat early chronic SCI. Moreover, it will establish whether cytotherapy can ameliorate local hostile microenvironments, promote tracking fiber regeneration, and strengthen spinal conduction ability, thus improving overall motor, sensory, and micturition/defecation function in patients with early chronic SCI. This study was approved by the Stem Cell Research Ethics Committee of the Third Affiliated Hospital of Sun Yat-sen University, China (approval No. [2018]-02) on March 30, 2018, and was registered with ClinicalTrials.gov (registration No. NCT03521323) on April 12, 2018. The revised trial protocol (protocol version 4.0) was approved by the Stem Cell Research Ethics Committee of the Third Affiliated Hospital of Sun Yat-sen University, China (approval No. [2019]-10) on February 25, 2019, and released on ClinicalTrials.gov on April 29, 2019.

Application of Hepatocyte Growth Factor for Acute Spinal Cord Injury: The Road from Basic Studies to Human Treatment

Hepatocyte growth factor (HGF) was first identified as a potent mitogen for mature hepatocytes, and has also gained attention as a strong neurotrophic factor in the central nervous system. We found that during the acute phase of spinal cord injury (SCI) in rats, c-Met, the specific receptor for HGF, increases sharply, while the endogenous HGF up-regulation is relatively weak. Introducing exogenous HGF into the spinal cord by injecting an HGF-expressing viral vector significantly increased the neuron and oligodendrocyte survival, angiogenesis, and axonal regeneration, to reduce the area of damage and to promote functional recovery in rats after SCI. Other recent studies in rodents have shown that exogenously administered HGF during the acute phase of SCI reduces astrocyte activation to decrease glial scar formation, and exerts anti-inflammatory effects to reduce leukocyte infiltration. We also reported that the intrathecal infusion of recombinant human HGF (intrathecal rhHGF) improves neurological hand function after cervical contusive SCI in the common marmoset, a non-human primate. Based on these collective results, we conducted a phase I/II clinical trial of intrathecal rhHGF for patients with acute cervical SCI who showed a modified Frankel grade of A/B1/B2 72 h after injury onset, from June 2014 to May 2018.