Riluzole in Spinal Cord Injury Study (RISCIS)-Pharmacokinetic (PK) Sub-Study: An Analysis of Pharmacokinetics, Pharmacodynamics, and Impact on Axonal Degradation of Riluzole in Patients With Traumatic Cervical Spinal Cord Injury Enrolled in the RISCIS Phase III Randomized Controlled Trial.

To date, no drug therapy has shown significant efficacy in improving functional outcomes in patients with acute spinal cord injury (SCI). Riluzole is an approved benzothiazole sodium channel blocker to attenuate neurodegeneration in amyotrophic lateral sclerosis (ALS) and is of interest for neuroprotection in SCI. In a Phase I clinical trial (ClinicalTrials.gov Identifier: NCT00876889), riluzole was well tolerated with a 2-week treatment at the dose level approved for ALS and exhibited potential efficacy in patients with SCI. The acute and progressive nature of traumatic SCI and the complexity of secondary injury processes alter the pharmacokinetics (PK) of therapeutics. In the PK sub-study of the multi-center, randomized, placebo-controlled, double-blinded Riluzole in Spinal Cord Injury Study (RISCIS) Phase II/III trial (ClinicalTrials.gov Identifier: NCT01597518), a total of 32 SCI patients were enrolled, and most of our patients were middle-age Caucasian males with head and neck injuries. We studied the PK and pharmacodynamics (PD) of riluzole on motor recovery, measured by International Standards for Neurological Classification of SCI (ISNCSCI) Motor Score at injury and at 3-month and 6-month follow-ups, along with levels of the axonal injury biomarker phosphorylated neurofilament heavy chain (pNF-H), during the 2-week treatment. PK modeling, PK/PD correlations were developed to identify the potential effective exposure of riluzole for intended PD outcomes. The longitudinal impacts of SCI on the PK of riluzole are characterized. A time-varying population PK model of riluzole is established, incorporating time-varying clearance and volume of distribution from combined data of Phase I and Phase II/III trials. With the developed model, a rational, optimal dosing scheme can be designed with time-dependent modification to preserve the required therapeutic exposure of riluzole. The PD of riluzole and the relationship between PK and neurological outcomes of the treatment were established. The time course of efficacy in total motor score improvement (ΔTMS) and pNF-H were monitored. A three-dimensional (3D) PK/PD correlation was established for ΔTMS at 6 months with overall riluzole exposure area under the curve for Day 0-Day14 (AUCD0-D14) and baseline TMS for individual patients. Patients with baseline TMS between 1 and 36 benefited from the optimal exposure range of 16-48 mg*h/mL. The PD models of pNF-H revealed the riluzole efficacy, as treated subjects exhibited a diminished increase in progression of pNF-H, indicative of reduced axonal breakdown. The independent parameter of area between effective curves (ABEC) between the time profiles of pNF-H in placebo and treatment groups was statistically identified as a significant predictor for the treatment effect on the biomarker. A mechanistic clinical outcomes (CO)/PD (pNF-H) model was established, and the proposed structure demonstrated the feasibility of PK/PD/CO correlation model. No appreciable hepatic toxicity was observed with the current riluzole treatment regimen. The development of effective treatment for SCI is challenging. However, the future model-informed and PK-guided drug development and regimen modification can be rationally executed with the optimal dosing regimen design based on the developed 3D PK/PD model. The PK/PD/CO model can serve as a rational guide for future drug development, PKPD model refinement, and extension to other studies in SCI settings.

How good are the outcomes of instrumented debulking operations for symptomatic spinal metastases and how long do they stand? A subgroup analysis in the global spine tumor study group database.

BACKGROUND: The benefits of surgery for symptomatic spinal metastases have been demonstrated, largely based on series of patients undergoing debulking and instrumentation operations. However, as cancer treatments improve and overall survival lengths increase, the incidence of recurrent spinal cord compression after debulking may increase. The aim of the current paper is to document the postoperative evolution of neurological function, pain, and quality of life following debulking and instrumentation in the Global Spine Tumor Study Group (GSTSG) database. METHODS: The GSTSG database is a prospective multicenter data repository of consecutive patients that underwent surgery for a symptomatic spinal metastasis. For the present analysis, patients were selected from the database that underwent decompressive debulking surgery with instrumentation. Preoperative tumor type, Tomita and Tokuhashi scores, EQ-5D, Frankel, Karnofsky, and postoperative complications, survival, EQ-5D, Frankel, Karnofsky, and pain numeric rating scores (NRS) at 3, 6, 12, and 24 months were analyzed. RESULTS: A total of 914 patients underwent decompressive debulking surgery with instrumentation and had documented follow-up until death or until 2 years post surgery. Median preoperative Karnofsky performance index was 70. A total of 656 patients (71.8%) had visceral metastases and 490 (53.6%) had extraspinal bone metastases. Tomita scores were evenly distributed above (49.1%) and below or equal to 5 (50.9%), and Tokuhashi scores almost evenly distributed below or equal to 8 (46.3%) and above 8 (53.7%). Overall, 12-month survival after surgery was 56.3%. The surgery resulted in EQ-5D health status improvement and NRS pain reduction that was maintained throughout follow-up. Frankel scores improved at first follow-up in 25.0% of patients, but by 12 months neurological deterioration was observed in 18.8%. CONCLUSION: We found that palliative debulking and instrumentation surgeries were performed throughout all Tomita and Tokuhashi categories. These surgeries reduced pain scores and improved quality of life up to 2 years after surgery. After initial improvement, a proportion of patients experienced neurological deterioration by 1 year, but the majority of patients remained stable.

A novel risk calculator to predict outcome after surgery for symptomatic spinal metastases; use of a large prospective patient database to personalise surgical management.

AIM: Surgery for spinal metastases can improve symptoms, but sometimes complications can negate the benefits. Operations may have different indications, complexities and risks, and the choice for an individual is a tailor-made personalised decision. Previous prognostic scoring systems are becoming out of date and inaccurate. We designed a risk calculator to estimate survival after surgery, to inform clinicians and patients when making management decisions. METHODS: A prospective cohort study was performed, including 1430 patients with spinal metastases who underwent surgery. Of them, 1264 patients from 20 centres were used for model development using a Cox frailty model. Calibration slope, D-statistic and C-index were used for model validation based on 166 patients. Follow-up was to death or minimum of 2 years after surgery. Pre-operative indices (examination findings, pain, Karnofsky physical functioning score, and radiology) were assessed. RESULTS: An algorithm to predict survival was constructed including the tumour type, ambulatory status, analgesic use, American Society of Anesthesiologists score, number of spinal metastases, previous radiotherapy or chemotherapy, presence of visceral metastases, cervical or thoracic spine involvement, as predictors. An Internet-based risk calculator was developed based on this algorithm, with similar or improved accuracy compared to other validated prognostic scoring systems (C-index, 0.68; 95% confidence interval, 0.63--0.73, and calibration slope, 1.00; 95% confidence interval, 0.68--1.32). CONCLUSION: A large, prospective, surgical series of patients with symptomatic spinal metastases was used to create a validated risk calculator that can help clinicians to inform patients about the most appropriate treatment plan. The calculator is available at www.spinemet.com.

Loss of Local Tumor Control After Index Surgery for Spinal Metastases: A Prospective Cohort Study.

BACKGROUND: As survival after treatment for symptomatic spinal metastases increases, the incidence of local tumor recurrence also may increase. However, data regarding incidence and timing of recurrence or duration of survival after second surgeries are not readily available and may help to inform clinicians when to perform second surgeries. OBJECTIVE: To identify features associated with loss of local control (LLC) at a previously treated or new spinal level. METHODS: Clinical and surgical data were collected from a prospective cohort of 1421 patients who had surgery for symptomatic spinal metastases. Patients undergoing repeat spinal surgery for symptomatic LLC at the same or a different level were identified and analyzed. RESULTS: In total, 3.0% patients underwent repeat surgery for symptomatic LLC after a median interval of 184 days from the first surgery; median survival was 6.1 months after second surgery. Factors associated with second surgery for LLC were the primary tumor type, number of spinal levels, Tomita staging, Tokuhashi and Karnofsky scores, anterior surgical approach, more aggressive surgical resection, and postoperative radiotherapy. In total, 1.5% patients were admitted for surgery for a different spinal level than the index operation after median 338 days from the first operation. CONCLUSIONS: The likelihood for repeat surgery due to LLC cannot be accurately predicted at the time of initial presentation. Factors associated with second surgery for LLC relate to less aggressive tumor biology and better survival. Most patients had a reasonable duration of survival after second surgery.

Characteristics of Patients Who Survived < 3 Months or > 2 Years After Surgery for Spinal Metastases: Can We Avoid Inappropriate Patient Selection?

PURPOSE: Survival after metastatic cancer has improved at the cost of increased presentation with metastatic spinal disease. For patients with pathologic spinal fractures and/or spinal cord compression, surgical intervention may relieve pain and improve quality of life. Surgery is generally considered to be inappropriate if anticipated survival is < 3 months. The aim of this international multicenter study was to analyze data from patients who died within 3 months or 2 years after surgery, to identify preoperative factors associated with poor or good survival, and to avoid inappropriate selection of patients for surgery in the future. PATIENTS AND METHODS: A total of 1,266 patients underwent surgery for impending pathologic fractures and/or neurologic deficits and were prospectively observed. Data collected included tumor characteristics, preoperative fitness (American Society of Anesthesiologists advisory [ASA]), neurologic status (Frankel scale), performance (Karnofsky performance score [KPS]), and quality of life (EuroQol five-dimensions questionnaire [EQ-5D]). Outcomes were survival at 3 months and 2 years postsurgery. Univariable and multivariable logistic regression analyses were used to find preoperative factors associated with short-term and long-term survival. RESULTS: In univariable analysis, age, emergency surgery, KPS, EQ-5D, ASA, Frankel, and Tokuhashi/Tomita scores were significantly associated with short survival. In multivariable analysis, KPS and age were significantly associated with short survival (odds ratio [OR], 1.36; 95% CI, 1.15 to 1.62; and OR, 1.14; 95% CI, 1.02 to 1.27, respectively). Associated with longer survival in univariable analysis were age, number of levels included in surgery, KPS, EQ-5D, Frankel, and Tokuhashi/Tomita scores. In multivariable analysis, the number of levels included in surgery (OR, 1.21; 95% CI, 1.06 to 1.38) and primary tumor type were significantly associated with longer survival. CONCLUSION: Poor performance status at presentation is the strongest indicator of poor short-term survival, whereas low disease load and favorable tumor histology are associated with longer-term survival.

Rapid improvements in pain and quality of life are sustained after surgery for spinal metastases in a large prospective cohort.

Introduction Metastatic spinal cancer is a common condition that may lead to spinal instability, pain and paralysis. In the 1980s, surgery was discouraged because results showed worse neurological outcomes and pain compared with radiotherapy alone. However, with the advent of modern imaging and spinal stabilisation techniques, the role of surgery has regained centre stage, though few studies have assessed quality of life and functional outcomes after surgery. Objective We investigated whether surgery provides sustained improvement in quality of life and pain relief for patients with symptomatic spinal metastases by analysing the largest reported surgical series of patients with epidural spinal metastases. Methods A prospective cohort study of 922 consecutive patients with spinal metastases who underwent surgery, from the Global Spine Tumour Study Group database. Pre- and post-operative EQ-5D quality of life, visual analogue pain score, Karnofsky physical functioning score, complication rates and survival were recorded. Results Quality of life (EQ-5D), VAS pain score and Karnofsky physical functioning score improved rapidly after surgery and these improvements were sustained in those patients who survived up to 2 years after surgery. In specialised spine centres, the technical intra-operative complication rate of surgery was low, however almost a quarter of patients experienced post-operative systemic adverse events. Conclusion Surgical treatment for spinal metastases produces rapid pain relief, maintains ambulation and improves good quality of life. However, as a group, patients with cancer are vulnerable to post-operative systemic complications, hence the importance of appropriate patient selection.

Absence of localized grey matter volume changes in the motor cortex following spinal cord injury.

The consequences of spinal cord injury (SCI) have considerable effects on motor function, typically resulting in functional impairment. Pathological changes have been studied at the site of trauma, rostrocaudally within the cord, and in the periphery. Few studies, however, have investigated the consequences of SCI at the cortical level. Magnetic resonance imaging (MRI) was used to explore the morphological changes in the grey and white matter within the primary motor (M1) cortex of individuals with cervical SCI. The "precentral knob," a landmark of M1 cortex dedicated to hand function, was selected for regionally specific measurements of change. Thirty-one hemispheres of SCI subjects and 28 hemispheres of control subjects were compared using a manual measurement after the images were segmented into grey matter, white matter, and cerebral spinal fluid (CSF). No significant differences in grey matter area measured at the precentral knob were found with the manual approach. An automated voxel-based morphometric analysis was also performed and demonstrated no significant differences in grey or white matter volume within an M1 region of interest. These data suggest that there is no gross anatomical change within M1 following cervical SCI. Our previously reported findings of reorganization of cortical motor output maps following SCI therefore likely result from changes in functional organization rather than anatomical changes.