Treatment effects for which shift or binary analyses are advantageous in acute stroke trials

Delayed treatment with a novel neurotrophic compound reduces behavioral deficits in rabbit ischemic stroke

Acute ischemic stroke is a major risk for morbidity and mortality in our aging population. Currently only one drug, the thrombolytic tissue plasminogen activator, is approved by the US Food and Drug Administration to treat stroke. Therefore, there is a need to develop new drugs that promote neuronal survival following stroke. We have synthesized a novel neuroprotective molecule called CNB-001 (a pyrazole derivative of curcumin) that has neurotrophic activity, enhances memory, and blocks cell death in multiple toxicity assays related to ischemic stroke. In this study, we tested the efficacy of CNB-001 in a rigorous rabbit ischemic stroke model and determined the molecular basis of its in vivo activity. CNB-001 has substantial beneficial properties in an in vitro ischemia assay and improves the behavioral outcome of rabbit ischemic stroke even when administered 1 h after the insult, a therapeutic window in this model comparable to tissue plasminogen activator. In addition, we elucidated the protein kinase pathways involved in neuroprotection. CNB-001 maintains the calcium-calmodulin-dependent kinase signaling pathways associated with neurotrophic growth factors that are critical for the maintenance of neuronal function. On the basis of its in vivo efficacy and novel mode of action, we conclude that CNB-001 has a great potential for the treatment of ischemic stroke as well as other CNS pathologies.

Meta-analysis of randomized intra-arterial thrombolytic trials for the treatment of acute stroke due to middle cerebral artery occlusion

BACKGROUND

Randomized clinical trials supporting the use of intra-arterial administration of thrombolytics (IAT) for the treatment of stroke due to middle cerebral artery (MCA) occlusion have been positive on some, but not all, endpoints. A meta-analysis was performed to estimate with more precision the effect of IAT on several key clinical endpoints.

METHODS

All randomized trials of IAT in the treatment of MCA stroke were identified by PUBMED search and by hand search of potentially relevant references. Trial methodologies were assessed for compatibility in study protocols and statistical analysis. A meta-analysis was performed evaluating the effect of IAT on functional outcome at 90 days and symptomatic intracranial hemorrhage (SICH) within 24 h.

RESULTS

Three trials met the criteria for the meta-analysis. IAT treated patients were significantly more likely to have a modified Rankin scale (mRS) ≤ 1 (31% vs 20%, OR 2.0, 95% CI 1.2 to 3.4, p=0.01); mRS ≤ 2 (43% vs 31%, OR 1.9, 95% CI 1.2 to 3.0, p=0.01); and NIH Stroke Scale score 0 or 1 (23% vs 12%, OR 2.4, 95% CI 1.3 to 4.4, p=0.007) at the 90 day follow-up. There was no effect on mortality at 90 days (20% vs 19%, OR 0.84, 95% CI 0.5 to 1.5). The risk of SICH was significantly increased in the active treatment arms (11% vs 2%, OR 4.6, 95% CI 1.3 to 16, p=0.02).

CONCLUSIONS

Our meta-analysis demonstrates that all standard functional endpoints for stroke trials were substantially improved in the active treatment arms. Despite an increased risk of SICH, there was no effect on mortality. These results support endovascular treatment of acute ischemic stroke due to MCA occlusion with intra-arterial thrombolytics.

Taking a light approach to treating acute ischemic stroke patients: transcranial near-infrared laser therapy translational science

Transcranial near-infrared laser therapy (NILT) has been investigated as a novel neuroprotective treatment for acute ischemic stroke (AIS), for approximately 10 years. Two clinical trials, NeuroThera Effectiveness and Safety Trial (NEST)-1 and NEST-2, have evaluated the use of NILT to promote clinical recovery in patients with AIS. This review covers preclinical, translational, and clinical studies documented during the period 1997-2010. The primary aim of this article is to detail the development profile of NILT to treat AIS. Secondly, insight into possible mechanisms involved in light therapy will be presented. Lastly, possible new directions that should be considered to improve the efficacy profile of NILT in AIS patients will be discussed. The use of NILT was advanced to clinical trials based upon extensive translational research using multiple species. NILT, which may promote functional and behavioral recovery via a mitochondrial mechanism and by enhancing cerebral blood flow, may eventually be established as an Food and Drug Administration (FDA)-approved treatment for stroke. The NEST-3 trial, which is the pivotal trial for FDA approval, should incorporate hypotheses derived from translational studies to ensure efficacy in patients. Future NILT studies should consider administration of a thrombolytic to enhance cerebral reperfusion alongside NILT neuroprotection.

Comparison of outcomes following thrombolytic therapy among patients with prior stroke and diabetes in the Virtual International Stroke Trials Archive (VISTA)

OBJECTIVE

The use of alteplase in patients who have had a prior stroke and concomitant diabetes is not approved in Europe. To examine the influence of diabetes and prior stroke on outcomes, we compared data on thrombolysed patients with nonthrombolysed comparators.

RESEARCH DESIGN AND METHODS

We selected patients with ischemic stroke on whom we had data on age, pretreatment baseline National Institutes of Health Stroke Scale (b-NIHSS), and 90-day outcome measures (functional modified Rankin score [mRS]) and neurological measures [NIHSS]) in the Virtual International Stroke Trials Archive. We compared outcomes between thrombolysed patients and nonthrombolysed comparators in those with and without diabetes, those who have had a prior stroke, or both and report findings using the Cochran-Mantel-Haenszel (CMH) test and proportional odds logistic regression analyses. We report an age-adjusted and b-NIHSS-adjusted CMH P value and odds ratio (OR).

RESULTS

Rankin data were available for 5,817 patients: 1,585 thrombolysed patients and 4,232 nonthrombolysed comparators. A total 1,334 (24.1%) patients had diabetes, 1,898 (33.7%) patients have had a prior stroke, and 491 (8%) patients had both. Diabetes and nondiabetes had equal b-NIHSS (median 13; P = 0.3), but patients who have had a prior stroke had higher b-NIHSS than patients who have not had a prior stroke (median 13 vs. 12; P < 0.0001). Functional outcomes were better for thrombolysed patients versus nonthrombolysed comparators among both nondiabetic (P < 0.0001; OR 1.4 [95% CI 1.3-1.6]) and diabetic (P = 0.1; 1.3 [1.05-1.6 ]) subjects. Similarly, outcomes were better for thrombolysed patients versus nonthrombolysed comparators among who have not had a prior stroke (P < 0.0001; 1.4 [1.2-1.6 ]) and those who have (P = 0.02; 1.3 [1.04-1.6 ]). There was no interaction of diabetes and prior stroke with treatment (P = 0.8). Neurological outcomes were consistent with the mRS.

CONCLUSIONS

Outcomes from thrombolysis are better among patients with diabetes and/or those who have had a prior stroke than in control subjects. Withholding thrombolytic treatment from otherwise-eligible patients may not be justified.

Thrombolysis in very elderly people: controlled comparison of SITS International Stroke Thrombolysis Registry and Virtual International Stroke Trials Archive

OBJECTIVE

To assess effect of age on response to alteplase in acute ischaemic stroke.

DESIGN

Adjusted controlled comparison of outcomes between non-randomised patients who did or did not undergo thrombolysis. Analysis used Cochran-Mantel-Haenszel test and proportional odds logistic regression analysis.

SETTING

Collaboration between International Stroke Thrombolysis Registry (SITS-ISTR) and Virtual International Stroke Trials Archive (VISTA).

PARTICIPANTS

23 334 patients from SITS-ISTR (December 2002 to November 2009) who underwent thrombolysis and 6166 from VISTA neuroprotection trials (1998-2007) who did not undergo thrombolysis (as controls). Of the 29 500 patients (3472 aged >80 ("elderly," mean 84.6), data on 272 patients were missing for baseline National Institutes of Health stroke severity score, leaving 29 228 patients for analysis adjusted for age and baseline severity.

MAIN OUTCOME MEASURES

Functional outcomes at 90 days measured by score on modified Rankin scale.

RESULTS

Median severity at baseline was the same for patients who underwent thrombolysis and controls (median baseline stroke scale score: 12 for each group, P=0.14; n=29 228). The distribution of scores on the modified Rankin scale was better among all thrombolysis patients than controls (odds ratio 1.6, 95% confidence interval 1.5 to 1.7; Cochran-Mantel-Haenszel P<0.001). The association occurred independently among patients aged ≤80 (1.6, 1.5 to 1.7; P<0.001; n=25 789) and in those aged >80 (1.4, 1.3 to 1.6; P<0.001; n=3439). Odds ratios were consistent across all 10 year age ranges above 30, and benefit was significant from age 41 to 90; dichotomised outcomes (score on modified Rankin scale 0-1 v 2-6; 0-2 v 3-6; and 6 (death) v rest) were consistent with the results of the ordinal analysis.

CONCLUSIONS

Outcome in patients with acute ischaemic stroke is significantly better in those who undergo thrombolysis compared with those who do not. Increasing age is associated with poorer outcome but the association between thrombolysis treatment and improved outcome is maintained in very elderly people. Age alone should not be a barrier to treatment.

Years of optimum health lost due to complications after acute ischemic stroke: disability-adjusted life-years analysis

BACKGROUND AND PURPOSE

Complications after stroke increase disability or death. The disability-adjusted life-year (DALY) metric, developed by the World Health Organization to measure the global burden of disease, integrates both mortality and disability. Widely used in population-level data analyses, it has not been applied to individual patient-level data captured in outcome registries.

METHODS

We analyzed patient-level data from the outcome registry of 1254 consecutive patients with acute ischemic stroke enrolled between September 1, 2004, and August 31, 2005, in South Korea. For each subject, we calculated DALY lost due to the qualifying stroke and then analyzed additional DALY lost due to complications after stroke.

RESULTS

For 1233 patients with available 3-month outcomes, the average DALY lost due to the index stroke was 3.82 (95% CI, 3.68 to 3.96). Any complications, neurological complications, and medical complications occurred in 34.0%, 20.8%, and 24.0%, respectively. The additional DALYs lost associated with any, neurological, and medical complications were 2.11 (95% CI, 1.78 to 2.44), 2.15 (95% CI, 1.72 to 2.59), and 1.99 (95% CI, 1.59 to 2.40), respectively. Patients with 1 complication had 1.52 (95% CI, 1.15 to 1.89) additional DALY lost, and those with >or=2 complications had 2.69 (95% CI, 2.18 to 3.20) additional DALY lost.

CONCLUSIONS

Early poststroke complications deprive patients of approximately 2 years of optimum health. Greater numbers of complications are associated with greater loss of healthy life-years. DALY analysis quantifies the burden of poststroke complications with a uniform metric potentially useful for health system planners.

Repeated-measures analysis of the National Institute of Neurological Disorders and Stroke rt-PA stroke trial

Previous analyses, including the National Institute of Neurological Disorders and Stroke (NINDS) rt-PA Stoke Trial, have assessed the clinical treatment efficacy only at single study point, but did not assess efficacy using outcomes collected at multiple time points and incorporate within-patient correlation. The data from the NINDS rt-PA Stroke Trial was analyzed with repeated-measures analysis with generalized estimating equations (GEE) approach using dichotomized outcomes (modified Rankin Scale [mRS], National Institutes of Health Stroke Scale [NIHSS], Barthel Index [BI], and Glasgow Outcome Scale [GOS]). The results were compared with data from previous analyses. All of the outcome variables at different time points were significantly correlated. rt-PA was superior to placebo overall and at specific time points individually. The overall odds of having minimal or no disability (mRS score 0 or 1) for patients treated with rt-PA was higher than those treated with placebo (odds ratio [OR], 2.1; 95% confidence interval [CI], 1.5-3.0). The ORs were 2.3 (95% CI, 1.5-3.4) times higher at 3 months, 1.9 (95% CI, 1.3-2.8) times higher at 6 months, and 2.0 (95% CI, 1.3-2.9) times higher at 12 months. A similar treatment effect also was observed with the NIHSS, BI, and GOS. Compared with previous analyses, an augmented treatment effect with larger ORs and smaller P values were observed. Repeated-measures analysis provides an alternative method for assessing treatment effect, as demonstrated in the analysis of data from the NINDS rt-PA Stroke Trial. This method could be used in future stroke trials in which outcomes of interest are collected at multiple time points.

Improving the reliability of stroke disability grading in clinical trials and clinical practice: the Rankin Focused Assessment (RFA)

BACKGROUND AND PURPOSE

The modified Rankin Scale rates global disability after stroke and is the most comprehensive and widely used primary outcome measure in acute stroke trials. However, substantial interobserver variability in modified Rankin Scale scoring has been reported. This study sought to develop and validate a short, practicable structured assessment that would enhance interrater reliability.

METHODS

The Rankin Focused Assessment was developed by selecting and refining elements from prior instruments. The Rankin Focused Assessment takes 3 to 5 minutes to apply and provides clear, operationalized criteria to distinguish the 7 assignable global disability levels. The Rankin Focused Assessment was prospectively validated 3 months poststroke among 50 consecutive patients enrolled in the Phase 3 National Institutes of Health Field Administration of Stroke Therapy-Magnesium (FAST-MAG) Trial.

RESULTS

Among the 50 patients, mean age was 71.5 years (range, 43 to 93 years), 48% were female, and stroke subtype was hemorrhagic in 24%. At Day 90, 43 patients were alive and 7 had died. The modified Rankin Scale median was 2.0 and mean was 2.8. When pairs of 14 raters assessed all enrolled patients, the percent agreement was 94%, the weighted kappa was 0.99 (95% CI, 0.99 to 1.0), and the unweighted kappa was 0.93 (95% CI, 0.85 to 1.00). Among the 43 surviving patients, the percent agreement was 93%, the weighted kappa was 0.99 (0.98 to 1.0), and the unweighted kappa was 0.91 (0.82 to 1.00).

CONCLUSIONS

The Rankin Focused Assessment yields high interrater reliability in the grading of final global disability among consecutive patients with stroke participating in a randomized clinical trial. The Rankin Focused Assessment is brief and practical for use in multicenter clinical trials and quality improvement activities.

A simulation study evaluating approaches to the analysis of ordinal outcome data in randomized controlled trials in traumatic brain injury: results from the IMPACT Project

BACKGROUND

Clinical trials in traumatic brain injury have a disappointing track record, with a long history of 'negative' Phase III trials. One contributor to this lack of success is almost certainly the low efficiency of the conventional approach to the analysis, which discards information by dichotomizing an ordinal outcome scale.

PURPOSE

Our goal was to evaluate the potential efficiency gains, which can be achieved by using techniques, which extract additional information from ordinal outcome data - the proportional odds model and the sliding dichotomy. In addition, we evaluated the additional efficiency gains, which can be achieved through covariate adjustment.

METHODS

The study was based on simulations, which were built around a database of patient-level data extracted from eight Phase III trials and three observational studies in traumatic brain injury. Two different putative treatment effects were explored, one which followed the proportional odds model, and the other which assumed that the effect of the intervention was to reduce the risk of death without changing the distribution of outcomes within survivors. The results are expressed as efficiency gains, reported as the percentage reduction in sample size that can be used with the ordinal analyses without loss of statistical power relative to the conventional binary analysis.

RESULTS

The simulation results show substantial efficiency gains. Use of the sliding dichotomy allows sample sizes to be reduced by up to 40% without loss of statistical power. The proportional odds model gives modest additional gains over and above the gains achieved by use of the sliding dichotomy.

LIMITATIONS

As with any simulation study, it is difficult to know how far the findings may be extrapolated beyond the actual situations that were modeled.

CONCLUSIONS

Both ordinal techniques offer substantial efficiency gains relative to the conventional binary analysis. The choice between the two techniques involves subtle value judgments. In the situations examined, the proportional odds model gave efficiency gains over and above the sliding dichotomy, but arguably, the sliding dichotomy is more intuitive and clinically appealing.