Found in translation: The rationale behind the early development of glibenclamide in large hemispheric infarction.

Many reasons have been put forth to explain the inability to translate neuroprotection in animal stroke models to humans. Following our determination that glibenclamide is an anti-edema drug, not a neuroprotective drug, and the revelation that the "gold standard" middle cerebral artery occlusion used for animal studies models large hemispheric infarction, a subpopulation of ischemic stroke that develops clinically relevant edema that contributes significantly to poor outcomes, we designed an innovative approach to studying the drug in patients with large hemispheric infarction. The approach included careful selection of the relevant patient population, which gave us a high degree of confidence to move forward into humans. Initial human studies showed drug effects consistent with the animal studies. The considerations leading to the development plan are described.

Safety and efficacy of intravenous glyburide on brain swelling after large hemispheric infarction (GAMES-RP): a randomised, double-blind, placebo-controlled phase 2 trial.

BACKGROUND: Preclinical models of stroke have shown that intravenous glyburide reduces brain swelling and improves survival. We assessed whether intravenous glyburide (RP-1127; glibenclamide) would safely reduce brain swelling, decrease the need for decompressive craniectomy, and improve clinical outcomes in patients presenting with a large hemispheric infarction. METHODS: For this double-blind, randomised, placebo-controlled phase 2 trial, we enrolled patients (aged 18-80 years) with a clinical diagnosis of large anterior circulation hemispheric infarction for less than 10 h and baseline diffusion-weighted MRI image lesion volume of 82-300 cm(3) on MRI at 18 hospitals in the USA. We used web-based randomisation (1:1) to allocate patients to the placebo or intravenous glyburide group. Intravenous glyburide was given as a 0·13 mg bolus intravenous injection for the first 2 min, followed by an infusion of 0·16 mg/h for the first 6 h and then 0·11 mg/h for the remaining 66 h. The primary efficacy outcome was the proportion of patients who achieved a modified Rankin Scale (mRS) score of 0-4 at 90 days without undergoing decompressive craniectomy. Analysis was by per protocol. Safety analysis included all randomly assigned patients who received the study drug. This trial is registered with ClinicalTrials.gov, number NCT01794182. FINDINGS: Between May 3, 2013, and April 30, 2015, 86 patients were randomly assigned but enrolment was stopped because of funding reasons. The funder, principal investigators, site investigators, patients, imaging core, and outcomes personnel were masked to treatment. The per-protocol study population was 41 participants who received intravenous glyburide and 36 participants who received placebo. 17 (41%) patients in the intravenous glyburide group and 14 (39%) in the placebo group had an mRS score of 0-4 at 90 days without decompressive craniectomy (adjusted odds ratio 0·87, 95% CI 0·32-2·32; p=0·77). Ten (23%) of 44 participants in the intravenous glyburide group and ten (26%) of 39 participants in the placebo group had cardiac events (p=0·76), and four of 20 had serious adverse events (two in the intravenous glyburide group and two in the placebo group, p=1·00). One cardiac death occurred in each group (p=1·00). INTERPRETATION: Intravenous glyburide was well tolerated in patients with large hemispheric stroke at risk for cerebral oedema. There was no difference in the composite primary outcome. Further study is warranted to assess the potential clinical benefit of a reduction in swelling by intravenous glyburide. FUNDING: Remedy Pharmaceuticals.

Exploratory analysis of glyburide as a novel therapy for preventing brain swelling.

BACKGROUND: Malignant infarction is characterized by the formation of cerebral edema, and medical treatment is limited. Preclinical data suggest that glyburide, an inhibitor of SUR1-TRPM4, is effective in preventing edema. We previously reported feasibility of the GAMES-Pilot study, a two-center prospective, open label, phase IIa trial of 10 subjects at high risk for malignant infarction based on diffusion weighted imaging (DWI) threshold of 82 cm(3) treated with RP-1127 (glyburide for injection). In this secondary analysis, we tested the hypothesis that RP-1127 may be efficacious in preventing poor outcome when compared to controls. METHODS: Controls suffering large hemispheric infarction were obtained from the EPITHET and MMI-MRI studies. We first screened subjects for controls with the same DWI threshold used for enrollment into GAMES-Pilot, 82 cm(3). Next, to address imbalances, we applied a weighted Euclidean matching. Ninety day mRS 0-4, rate of decompressive craniectomy, and mortality were the primary clinical outcomes of interest. RESULTS: The mean age of the GAMES cohort was 51 years and initial DWI volume was 102 ± 23 cm(3). After Euclidean matching, GAMES subjects showed similar NIHSS, higher DWI volume, younger age and had mRS 0-4-90% versus 50% in controls p = 0.049; with a similar trend in mRS 0-3 (40 vs. 25%; p = 0.43) and trend toward lower mortality (10 vs. 35%; p = 0.21). CONCLUSIONS: In this pilot study, RP-1127-treated subjects showed better clinical outcomes when compared to historical controls. An adequately powered and randomized phase II trial of patients at risk for malignant infarction is needed to evaluate the potential efficacy of RP-1127.

Pilot study of intravenous glyburide in patients with a large ischemic stroke.

BACKGROUND AND PURPOSE: Preclinical and retrospective clinical data indicate that glyburide, a selective inhibitor of sulfonylurea receptor 1-transient receptor potential melastatin 4, is effective in preventing edema and improving outcome after focal ischemia. We assessed the feasibility of recruiting and treating patients with severe stroke while obtaining preliminary information on the safety and tolerability of RP-1127 (glyburide for injection). METHODS: We studied 10 patients with acute ischemic stroke, with baseline diffusion-weighted imaging lesion volumes of 82 to 210 cm3, whether treated with intravenous recombinant tissue-type plasminogen activator, age 18 to 80 years, and time to RP-1127≤10 hours. RESULTS: Recruitment was completed within 10 months. The mean age was 50.5 years, and baseline diffusion-weighted image lesion volume was 102±23 cm3. There were no serious adverse events related to drug and no symptomatic hypoglycemia. The increase in ipsilateral hemisphere volume was 50±33 cm3. The proportion of 90-day modified Rankin Scale≤4 was 90% (40% modified Rankin Scale, ≤3). CONCLUSIONS: RP-1127 at a dose of 3 mg/d was well tolerated and did not require any dose reductions. A clinical trial of RP-1127 is feasible. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT01268683.

Glibenclamide in cerebral ischemia and stroke.

The sulfonylurea receptor 1 (Sur1)-transient receptor potential 4 (Trpm4) channel is an important molecular element in focal cerebral ischemia. The channel is upregulated in all cells of the neurovascular unit following ischemia, and is linked to microvascular dysfunction that manifests as edema formation and secondary hemorrhage, which cause brain swelling. Activation of the channel is a major molecular mechanism of cytotoxic edema and "accidental necrotic cell death." Blockade of Sur1 using glibenclamide has been studied in different types of rat models of stroke: (i) in conventional non-lethal models (thromboembolic, 1-2 h temporary, or permanent middle cerebral artery occlusion), glibenclamide reduces brain swelling and infarct volume and improves neurological function; (ii) in lethal models of malignant cerebral edema, glibenclamide reduces edema, brain swelling, and mortality; (iii) in models with rtPA, glibenclamide reduces swelling, hemorrhagic transformation, and death. Retrospective studies of diabetic patients who present with stroke have shown that those whose diabetes is managed with a sulfonylurea drug and who are maintained on the sulfonylurea drug during hospitalization for stroke have better outcomes at discharge and are less likely to suffer hemorrhagic transformation. Here, we provide a comprehensive review of the basic science, preclinical experiments, and retrospective clinical studies on glibenclamide in focal cerebral ischemia and stroke. We also compare the preclinical work in stroke models to the updated recommendations of the Stroke Therapy Academic Industry Roundtable (STAIR). The findings reviewed here provide a strong foundation for a translational research program to study glibenclamide in patients with ischemic stroke.

Validating imaging biomarkers of cerebral edema in patients with severe ischemic stroke.

BACKGROUND: There is no validated neuroimaging marker for quantifying brain edema. We sought to test whether magnetic resonance imaging (MRI)-based metrics would reliably change during the early subacute period in a manner consistent with edema and whether they would correlate with relevant clinical endpoints. METHODS: Serial MRI studies from patients in the Echoplanar Imaging Thrombolytic Evaluation Trial with initial diffusion-weighted imaging (DWI) lesion volume >82 cm(3) were analyzed. Two independent readers outlined the hemisphere and lateral ventricle on the involved side and calculated respective volumes at baseline and days 3 to 5. We assessed interrater agreement, volume change between scans, and the association of volume change with early neurologic deterioration (National Institutes of Health Stroke Scale score worsening of ≥ 4 points), a 90-day modified Rankin scale (mRS) score of 0 to 4, and mortality. RESULTS: Of 12 patients who met study criteria, average baseline and follow-up DWI lesion size was 138 cm(3) and 234 cm(3), respectively. The mean time to follow-up MRI was 62 hours. Concordance correlation coefficients between readers were >0.90 for both hemisphere and ventricle volume assessment. Mean percent hemisphere volume increase was 16.2 ± 8.3% (P < .0001), and the mean percent ventricle volume decrease was 45.6 ± 16.9% (P < .001). Percent hemisphere growth predicted early neurologic deterioration (area under the curve [AUC] 0.92; P = .0005) and 90-day mRS 0 to 4 (AUC 0.80; P = .02). CONCLUSIONS: In this exploratory analysis of severe ischemic stroke patients, statistically significant changes in hemisphere and ventricular volumes within the first week are consistent with expected changes of cerebral edema. MRI-based analysis of hemisphere growth appears to be a suitable biomarker for edema formation.

A comparative evaluation of lingual retainer failure bonded with or without liquid resin.

OBJECTIVE: To prospectively evaluate and compare the effect of liquid resin on lingual retainer failure after a 2-year follow-up. MATERIALS AND METHODS: Fifty-two patients (26 males, 26 females) with a mean age of 18.3 ± 1.3 years at follow-up, were randomized into two groups: the resin group and the nonresin group. The lingual retainers in the resin group were bonded to the enamel surfaces with two-step bonding resin, Optibond FL, and Tetric EvoFlow. The nonresin group followed the same procedure of bonding retainers but without applying the Optibond FL. Retainer failure, calculus accumulation, and discoloration of composite pads adjacent to the retainers during the 2-year observation period were registered, compared, and statistically analyzed with a Fisher's exact test and chi-square test. RESULTS: In the resin group, the incidence of retainer failure was 4% and occurred at the composite-wire interface; in the nonresin group, the incidence was 27% and occurred at the enamel-composite interface. The difference between the groups was statistically significant (P  =  .049). The incidences of calculus accumulation and discoloration adjacent to the composite pads were 27% and 69% (P  =  .003 and P < .001) higher in the nonresin group, respectively. CONCLUSION: Application of resin in bonding of lingual retainers appears to reduce the incidence of retainer failure as well as the incidence of calculus accumulation and discoloration adjacent to the composite pads.