A double-blind, randomized trial of PY108-068 in acute ischemic cerebral infarction

Pre-clinical to Clinical Translational Failures and Current Status of Clinical Trials in Stroke Therapy: A Brief Review

In stroke (cerebral ischemia), despite continuous efforts both at the experimental and clinical level, the only approved pharmacological treatment has been restricted to tissue plasminogen activator (tPA). Stroke is the leading cause of functional disability and mortality throughout worldwide. Its pathophysiology starts with energy pump failure, followed by complex signaling cascade that ultimately ends in neuronal cell death. Ischemic cascade involves excessive glutamate release followed by raised intracellular sodium and calcium influx along with free radicals' generation, activation of inflammatory cytokines, NO synthases, lipases, endonucleases and other apoptotic pathways leading to cell edema and death. At the pre-clinical stage, several agents have been tried and proven as an effective neuroprotectant in animal models of ischemia. However, these agents failed to show convincing results in terms of efficacy and safety when the trials were conducted in humans following stroke. This article highlights the various agents which have been tried in the past but failed to translate into stroke therapy along with key points that are responsible for the lagging of experimental success to translational failure in stroke treatment.

Calcium antagonists for acute ischemic stroke

BACKGROUND

The sudden loss of blood supply in ischemic stroke is associated with an increase of calcium ions within neurons. Inhibiting this increase could protect neurons and might reduce neurological impairment, disability, and handicap after stroke.

OBJECTIVES

To assess the effects of calcium antagonists for reducing the risk of death or dependency after acute ischemic stroke. We investigated the influence of different drugs, dosages, routes of administration, time intervals after stroke, and trial design on the outcomes.

SEARCH METHODS

The evidence is current to 6 February 2018. We searched the Cochrane Stroke Group Trials Register (6 February 2018), Cochrane Central Register of Controlled Trials (CENTRAL; 2018, Issue 2), MEDLINE Ovid (1950 to 6 February 2018), Embase Ovid (1980 to 6 February 2018), and four Chinese databases (6 February 2018): Chinese Biological Medicine Database (CBM-disc), China National Knowledge Infrastructure (CNKI), Chinese Scientific Periodical Database of VIP information, and Wanfang Data. We also searched the following trials registers: ClinicalTrials.gov, EU Clinical Trials Register, Stroke Trials Registry, ISRCTN registry, WHO International Clinical Trials Registry Platform, and Chinese Clinical Trial Registry, and we contacted trialists and researchers.

SELECTION CRITERIA

Randomized controlled trials comparing a calcium antagonist versus control in people with acute ischemic stroke.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials, extracted data, assessed risk of bias, and applied the GRADE approach to assess the quality of the evidence. We used death or dependency at the end of long-term follow-up (at least three months) in activities of daily living as the primary outcome. We used standard Cochrane methodological procedures.

MAIN RESULTS

We included 34 trials involving 7731 participants. All the participants were in the acute stage of ischemic stroke, and their age ranged from 18 to 85 years, with the average age ranging from 52.3 to 74.6 years across different trials. There were more men than women in most trials. Twenty-six trials tested nimodipine, and three trials assessed flunarizine. One trial each used isradipine, nicardipine, PY108-608, fasudil, and lifarizine. More than half of these trials followed participants for at least three months. Calcium antagonists showed no effects on the primary outcome (risk ratio (RR) 1.05; 95% confidence interval (CI) 0.98 to 1.13; 22 trials; 22 studies; 6684 participants; moderate-quality evidence) or on death at the end of follow-up (RR 1.07, 95% CI 0.98 to 1.17; 31 trials; 7483 participants; moderate-quality evidence). Thirteen trials reported adverse events, finding no significant differences between groups. Most trials did not report the allocation process or how they managed missing data, so we considered these at high risk of selection and attrition bias. Most trials reported double-blind methods but did not state who was blinded, and none of the trial protocols were available.

AUTHORS' CONCLUSIONS

We found no evidence to support the use of calcium antagonists in people with acute ischemic stroke.

Interventions for deliberately altering blood pressure in acute stroke

BACKGROUND

It is unclear whether blood pressure should be altered actively during the acute phase of stroke. This is an update of a Cochrane review first published in 1997, and previously updated in 2001 and 2008.

OBJECTIVES

To assess the clinical effectiveness of altering blood pressure in people with acute stroke, and the effect of different vasoactive drugs on blood pressure in acute stroke.

SEARCH METHODS

We searched the Cochrane Stroke Group Trials Register (last searched in February 2014), the Cochrane Database of Systematic reviews (CDSR) and the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2014, Issue 2), MEDLINE (Ovid) (1966 to May 2014), EMBASE (Ovid) (1974 to May 2014), Science Citation Index (ISI, Web of Science, 1981 to May 2014) and the Stroke Trials Registry (searched May 2014).

SELECTION CRITERIA

Randomised controlled trials of interventions that aimed to alter blood pressure compared with control in participants within one week of acute ischaemic or haemorrhagic stroke.

DATA COLLECTION AND ANALYSIS

Two review authors independently applied the inclusion criteria, assessed trial quality and extracted data. The review authors cross-checked data and resolved discrepancies by discussion to reach consensus. We obtained published and unpublished data where available.

MAIN RESULTS

We included 26 trials involving 17,011 participants (8497 participants were assigned active therapy and 8514 participants received placebo/control). Not all trials contributed to each outcome. Most data came from trials that had a wide time window for recruitment; four trials gave treatment within six hours and one trial within eight hours. The trials tested alpha-2 adrenergic agonists (A2AA), angiotensin converting enzyme inhibitors (ACEI), angiotensin receptor antagonists (ARA), calcium channel blockers (CCBs), nitric oxide (NO) donors, thiazide-like diuretics, and target-driven blood pressure lowering. One trial tested phenylephrine.At 24 hours after randomisation oral ACEIs reduced systolic blood pressure (SBP, mean difference (MD) -8 mmHg, 95% confidence interval (CI) -17 to 1) and diastolic blood pressure (DBP, MD -3 mmHg, 95% CI -9 to 2), sublingual ACEIs reduced SBP (MD -12.00 mm Hg, 95% CI -26 to 2) and DBP (MD -2, 95%CI -10 to 6), oral ARA reduced SBP (MD -1 mm Hg, 95% CI -3 to 2) and DBP (MD -1 mm Hg, 95% CI -3 to 1), oral beta blockers reduced SBP (MD -14 mm Hg; 95% CI -27 to -1) and DBP (MD -1 mm Hg, 95% CI -9 to 7), intravenous (iv) beta blockers reduced SBP (MD -5 mm Hg, 95% CI -18 to 8) and DBP (-5 mm Hg, 95% CI -13 to 3), oral CCBs reduced SBP (MD -13 mmHg, 95% CI -43 to 17) and DBP (MD -6 mmHg, 95% CI -14 to 2), iv CCBs reduced SBP (MD -32 mmHg, 95% CI -65 to 1) and DBP (MD -13, 95% CI -31 to 6), NO donors reduced SBP (MD -12 mmHg, 95% CI -19 to -5) and DBP (MD -3, 95% CI -4 to -2) while phenylephrine, non-significantly increased SBP (MD 21 mmHg, 95% CI -13 to 55) and DBP (MD 1 mmHg, 95% CI -15 to 16).Blood pressure lowering did not reduce death or dependency either by drug class (OR 0.98, 95% CI 0.92 to 1.05), stroke type (OR 0.98, 95% CI 0.92 to 1.05) or time to treatment (OR 0.98, 95% CI 0.92 to 1.05). Treatment within six hours of stroke appeared effective in reducing death or dependency (OR 0.86, 95% CI 0.76 to 0.99) but not death (OR 0.70, 95% CI 0.38 to 1.26) at the end of the trial. Although death or dependency did not differ between people who continued pre-stroke antihypertensive treatment versus those who stopped it temporarily (worse outcome with continuing treatment, OR 1.06, 95% CI 0.91 to 1.24), disability scores at the end of the trial were worse in participants randomised to continue treatment (Barthel Index, MD -3.2, 95% CI -5.8, -0.6).

AUTHORS' CONCLUSIONS

There is insufficient evidence that lowering blood pressure during the acute phase of stroke improves functional outcome. It is reasonable to withhold blood pressure-lowering drugs until patients are medically and neurologically stable, and have suitable oral or enteral access, after which drugs can than be reintroduced. In people with acute stroke, CCBs, ACEI, ARA, beta blockers and NO donors each lower blood pressure while phenylephrine probably increases blood pressure. Further trials are needed to identify which people are most likely to benefit from early treatment, in particular whether treatment started very early is beneficial.

Calcium antagonists for acute ischemic stroke

BACKGROUND

The sudden loss of blood supply in ischemic stroke is associated with the increase of calcium ions within neurons. Inhibiting this increase could protect neurons and hence might reduce neurological impairment, disability and handicap after stroke.

OBJECTIVES

To determine whether calcium antagonists reduce the risk of death or dependency after acute ischemic stroke. To investigate the influence of different drugs, dosages, routes of administration, time intervals after stroke and trial design on the risk of a primary outcome.

SEARCH METHODS

We searched the Cochrane Stroke Group Trials Register (January 2012), MEDLINE (1950 to December 2011), EMBASE (1980 to December 2011), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, 2011 issue 4) and four Chinese databases (December 2011): Chinese Biological Medicine Database (CBM-disc), China National Knowledge Infrastructure (CNKI), Chinese scientific periodical database of VIP information and Wanfang Data. We also contacted trialists and researchers.

SELECTION CRITERIA

All truly randomized trials comparing a calcium antagonist with control in patients with acute ischemic stroke.

DATA COLLECTION AND ANALYSIS

Two authors assessed all trials and extracted the data. We used death or dependency at the end of long-term follow-up (at least three months) in activities of daily living as the primary outcome. Analyses were, if possible, intention-to-treat.

MAIN RESULTS

We included 34 trials including 7731 patients. There was no effect of calcium antagonists on the primary outcome (risk ratio (RR) 1.05; 95% confidence interval (CI) 0.98 to 1.13), or on death at the end of follow-up (RR 1.07, 95% CI 0.98 to 1.17). Comparisons of different doses of nimodipine suggested that the highest doses were associated with poorer outcome.

AUTHORS' CONCLUSIONS

No evidence is available using calcium antagonists in patients with acute ischemic stroke is effective.

Guidelines for the treatment of acute ischaemic stroke

INTRODUCTION

Update of Acute Ischaemic Stroke Treatment Guidelines of the Spanish Neurological Society based on a critical review of the literature. Recommendations are made based on levels of evidence from published data and studies.

DEVELOPMENT

Organized systems of care should be implemented to ensure access to the optimal management of all acute stroke patients in stroke units. Standard of care should include treatment of blood pressure (should only be treated if values are over 185/105 mmHg), treatment of hyperglycaemia over 155 mg/dl, and treatment of body temperature with antipyretic drugs if it rises above 37.5 °C. Neurological and systemic complications must be prevented and promptly treated. Decompressive hemicraniectomy should be considered in cases of malignant cerebral oedema. Intravenous thrombolysis with rtPA should be administered within 4.5 hours from symptom onset, except when there are contraindications. Intra-arterial pharmacological thrombolysis can be considered within 6 hours, and mechanical thrombectomy within 8 hours from onset, for anterior circulation strokes, while a wider window of opportunity up to 12-24 hours is feasible for posterior strokes. There is not enough evidence to recommend routine use of the so called neuroprotective drugs. Anticoagulation should be administered to patients with cerebral vein thrombosis. Rehabilitation should be started as early as possible.

CONCLUSION

Treatment of acute ischaemic stroke includes management of patients in stroke units. Systemic thrombolysis should be considered within 4.5 hours from symptom onset. Intra-arterial approaches with a wider window of opportunity can be an option in certain cases. Protective and restorative therapies are being investigated.

Vasoactive drugs for acute stroke

BACKGROUND

It is unclear whether blood pressure (BP) should be altered actively during the acute phase of stroke.

OBJECTIVES

To assess the effect of lowering or elevating BP in people with acute stroke, and the effect of different vasoactive drugs on BP in acute stroke.

SEARCH STRATEGY

We searched the Cochrane Stroke Group Trials Register (last searched June 2009), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 4, 2009), MEDLINE (1966 to October 2009), EMBASE (1980 to October 2009), and Science Citation Index (1981 to October 2009).

SELECTION CRITERIA

Randomised trials of interventions that would be expected, on pharmacological grounds, to alter BP in patients within one week of the onset of acute stroke.

DATA COLLECTION AND ANALYSIS

Two review authors independently applied the trial inclusion criteria, assessed trial quality, and extracted data.

MAIN RESULTS

We identified 131 trials involving in excess of 18,000 patients; a further 13 trials are ongoing. We obtained data for 43 trials (7649 patients). Among BP-lowering trials, beta receptor antagonists lowered BP (early systolic BP (SBP) mean difference (MD) -6.1 mmHg, 95% CI -11.4 to -0.9; late SBP MD -4.9 mmHg, 95% CI -10.2 to 0.4; late diastolic BP (DBP) MD -4.5 mmHg, 95% CI -7.8 to -1.2). Oral calcium channel blockers (CCB) lowered BP (late SBP MD -3.2 mmHg, 95% CI -5.4 to -1.1; early DBP MD -2.5, 95% CI -5.6 to 0.7; late DBP MD -2.1, 95% CI -3.5 to -0.7). Nitric oxide donors lowered BP (early SBP MD -10.3 mmHg, 95% CI -17.6 to -3.0). Prostacyclin lowered BP (late SBP MD, -7.7 mmHg, 95% CI -15.6 to 0.2; late DBP MD -3.9 mmHg, 95% CI -8.1 to 0.4). Among BP-increasing trials, diaspirin cross-linked haemoglobin (DCLHb) increased BP (early SBP MD 15.3 mmHg, 95% CI 4.0 to 26.6; late SBP MD 15.9 mmHg, 95% CI 1.8 to 30.0). None of the drug classes significantly altered outcome apart from DCLHb which increased combined death or dependency (odds ratio (OR) 5.41, 95% CI 1.87 to 15.64).

AUTHORS' CONCLUSIONS

There is not enough evidence to evaluate reliably the effect of altering BP on outcome after acute stroke. However, treatment with DCLHb was associated with poor clinical outcomes. Beta receptor antagonists, CCBs, nitric oxide, and prostacyclin each lowered BP during the acute phase of stroke. In contrast, DCLHb increased BP.

Vasoactive drugs for acute stroke

BACKGROUND

It is unclear whether blood pressure should be managed after acute stroke and if so whether it is best to reduce or increase blood pressure.

OBJECTIVES

The objective of this review was to assess the effect of lowering or elevating blood pressure in people with acute stroke, and the effect of different vasoactive drugs on blood pressure in acute stroke.

SEARCH STRATEGY

We searched the Cochrane Library (1999 Issue 1) using the CDSR and the CCTR databases, MEDLINE (from 1966), EMBASE (from 1980), BIDS ISI (Science Citation Index from 1981), and existing review articles. We contacted researchers in the field and pharmaceutical companies.

SELECTION CRITERIA

Randomised trials of interventions that would be expected, on pharmacological grounds, to alter blood pressure in patients within two weeks of the onset of acute ischaemic or haemorrhagic stroke.

DATA COLLECTION AND ANALYSIS

Two reviewers independently applied the trial inclusion criteria, assessed trial quality, and extracted the data.

MAIN RESULTS

Sixty five trials were identified involving in excess of 11,500 patients; a further 5 trials are ongoing. Data were obtained for 32 trials (5,368 patients). Significant imbalances in baseline blood pressure were present across trials of intravenous calcium channel blockers and prostacyclin. Major imbalances in baseline blood pressure between treatment and control groups have made the interpretation of these results difficult. Intravenous calcium channel blockers (CCBs) and oral CCBs significantly lowered late blood pressure as compared to controls. (systolic/diastolic BP): iv CCBs -8.2/-6.7 mm Hg (95% CI -12.6 to -3.8)/ (95% CI -9.2 to -4.3); oral CCBs -3.2/-2.1 mm Hg (95% CI -5.0 to -1.3)/ (95% CI -3.0 to -1.0). Beta blockers significantly lowered late diastolic blood pressure but not significantly late systolic blood pressure; -5.0/-4.5 mm Hg (95% CI -10.2 to 0.4)/(95% CI -7.8 to -1.15). Angiotensin converting enzyme inhibitors and prostacyclin non-significantly reduced late BP as compared to the controls by -5.4/-3.0 mm Hg (95% CI -16.5 to 5.8)/(95% CI -11.1 to 5.0) and -7.4/-3.9 mmHg (95% CI -15.6 to 0.2)/(95% CI -8.1 to 0.4) respectively. Magnesium, naftidrofuryl and piracetam had no significant effect on blood pressure. Oral CCBs and beta blockers each significantly reduced late heart rate (beats per minute (bpm)): CCBs -2.8 bpm (95%CI -3.9 to -1.7); beta blockers -9.3 bpm (95% CI -12.0 to -6.6). Prostacyclin significantly increased late heart rate by +5.6 bpm (95% CI 0.8 to 10.4). None of the drug classes significantly altered outcome apart from beta blockers and streptokinase which increased early case fatality (odds ratio 1.77, 95%CI, 1.05 to 3.00) and 2.27 (95% CI 1.4 to 3.67).

REVIEWER'S CONCLUSIONS

There is not enough evidence reliably to evaluate the effect of altering blood pressure on outcome after acute stroke. CCBs, beta blockers, and probably ACE-inhibitors, prostacyclin and nitric oxide, each lowered BP during the acute phase of stroke. In contrast, magnesium, naftidrofuryl and piracetam had little or no effect on BP.

Calcium antagonists for acute ischemic stroke

BACKGROUND

The sudden loss of blood supply in ischemic stroke is associated with increased levels of calcium ions within neurones. Inhibiting this increase could protect neurones and is thought to reduce neurological impairment, disability and handicap after stroke.

OBJECTIVES

The aim of this review is to determine whether calcium antagonists reduce the risk of death or dependency after acute ischemic stroke. The influence of different drugs, dosages, routes of administration, time intervals after stroke and trial design on the risk of poor outcome was investigated.

SEARCH STRATEGY

Relevant trials were identified in the Specialised Register of Controlled Trials (last searched: March 1999).

SELECTION CRITERIA

All truly randomised trials comparing a calcium antagonist with control in patients with acute ischaemic stroke were included.

DATA COLLECTION AND ANALYSIS

Two authors assessed all trials and extracted the data. Poor outcome, defined as death or dependency in activities of daily living, was used as the main outcome. Analyses were, if possible, "intention-to-treat".

MAIN RESULTS

46 trials were identified of which 28 were included (7521 patients). No effect of calcium antagonists on poor outcome at the end of follow-up (OR 1.07, 95% CI 0.97/1.18), or on death at end of follow-up (OR 1.10, 95% CI 0.98/1.24) was found. Intravenous administration (i.v.) of calcium antagonists was associated with an increase in the number of patients with poor outcome compared to oral administration (indirect comparisons). Comparisons of different doses of nimodipine suggested that the highest doses were associated with poorer outcome. Administration within 12 hours of onset was associated with an increase in the proportion of patients with poor outcome, but this effect was largely due to the poor results associated with i.v. administration. A subgroup analysis on nimodipine (oral, 120 mg/day) started within 12 hours of stroke onset, did not show a beneficial effect.

REVIEWER'S CONCLUSIONS

No evidence is available to justify the use of calcium antagonists in patients with acute ischaemic stroke.

Ethical considerations in neuroclinical trials

Ethical decision making in clinical trials has become increasingly emphasized at many levels of the review process. Ethical concepts applicable to Neuroclinical Trials (NCT) are reviewed. The discussion is directed towards ethical concerns that investigators must consider and justify prior to Institutional Review Board (IRB) submission. Risk-benefit analysis, methodology (randomization: placebo; design) and consent (informed; deferred; waived) are reviewed and Office for Protection from Research Risk (OPRR) guidelines are described. Our conclusions: Investigators proposing NCT face increasing ethical scrutiny by IRBs. Attention to ethical issues early in trial planning process is recommended.

Attenuation of ischemic and postischemic damage to brain metabolism and circulation by a novel Ca2+ channel antagonist, NC-1100, in spontaneously hypertensive rats

We investigated the effect of a newly synthesized Ca2+ channel antagonist, NC-1100, on cerebral blood flow (CBF) and metabolism in spontaneously hypertensive rats. The rats received a bolus injection of 0.2 or 1.0 mg/kg NC-1100 i.v. and 1-h cerebral ischemia was then induced by bilateral carotid artery occlusion (group 1). The rats in group 2 were continuously infused with NC-1100 0.03 or 0.1 mg/kg per min, starting immediately after bilateral carotid artery occlusion, for the 1 h of ischemia and following 3-h recirculation. Group 1: during ischemia, CBF in all rats decreased to 6-8% of the resting values. At 1 h cerebral ischemia, brain tissue lactate increased 11.5-, 10.1- and 9.8-fold of the normal control given vehicle or NC-1100, 0.2 and 1.0 mg/kg, respectively. The ATP levels were better preserved by NC-1100 administration; 0.61 +/- 0.04 (mean +/- S.E.M.), 0.80 +/- 0.09 and 0.97 +/- 0.14 mmol/kg (P < 0.05 vs. vehicle), respectively. Group 2: during recirculation, CBF in NC-1100-treated rats returned to 83-90% of the resting values, but to only 65% in the vehicle group. Postischemic brain lactate at 3 h was less well preserved and ATP was dose dependently better preserved in NC-1100- than vehicle-treated rats. It is considered that pre- as well as postischemic administration of a Ca2+ channel antagonist, NC-1100, is beneficial to attenuate and also ameliorate the metabolic and circulatory derangement in the ischemic brain.