spd-502 and Status-Epilepticus

Topics: Acetamides; Animals; Anticonvulsants; Carbamates; Disease Models, Animal; Fructose; Humans; Lacosamide; Pyrroles; Pyrrolidinones; Rats; Receptors, AMPA; Status Epilepticus; Tetrahydroisoquinolines; Topiramate; Treatment Outcome

Refractory status epilepticus (RSE) is a life-threatening condition that requires immediate and aggressive treatment. Unfortunately, sometimes standard antiepileptic treatment is insufficient. Furthermore, alternative therapeutic options are limited by low evidence of efficacy. The primary objective of this study was to evaluate the effects of the novel drug candidate, NS1209 versus third-line standard treatment (phenytoin/valproate) for RSE. Having not reached the study end-points, the purpose of this paper is to discuss the challenges that are encountered in conducting a controlled study of RSE. This was a phase II, prospective, multicentre, single-blinded, randomized clinical trial and included patients to two separate protocols for convulsive and non-convulsive RSE (NS1209-006 and NS1209-007). In total, 28 patients were included and 14 patients were exposed to NS1209. At study conclusion, the study was insufficiently powered to detect any statistically significant difference between the two treatment groups. This was especially true for the convulsive RSE protocol. We conclude that high-quality studies in RSE are difficult to conduct owing to a number of ethical and practical problems associated with this critical illness. Challenges for further studies are discussed.

Topics: Adult; Aged; Aged, 80 and over; Anticonvulsants; Clinical Trials, Phase II as Topic; Drug Resistance; Endpoint Determination; Female; Humans; Male; Middle Aged; Prospective Studies; Pyrroles; Randomized Controlled Trials as Topic; Receptors, AMPA; Research Design; Status Epilepticus; Tetrahydroisoquinolines; Treatment Outcome

The current first line treatment of status epilepticus (SE) is based on the use of compounds that enhance GABAergic transmission or block sodium channels. These treatments discontinue SE in only two-thirds of patients, and therefore new therapeutic approaches are needed. We investigated whether a novel water-soluble AMPA antagonist, NS1209, discontinues SE in adult rats. SE was induced by electrical stimulation of the amygdala or subcutaneous administration of kainic acid. Animals were monitored continuously with video-electroencephalography during SE and drug treatment. We found that NS1209 could be safely administered to rats undergoing electrically induced SE at doses up to 50mg/kg followed by intravenous infusion of 5mg/kg for up to 24h. NS1209 administered as a bolus dose of 10-50mg/kg (i.p. or i.v.) followed by infusion of 4 or 5mg/kg h (i.v.) for 2-24h effectively discontinued electrically induced SE in all animals within 30-60 min, and there was no recurrence of SE after a 24-h infusion. Kainate-induced SE was similarly blocked by 10 or 30 mg/kg NS1209 (i.v.). To compare the efficacy and neuroprotective effects of NS1209 with those of diazepam (DZP), one group of rats received DZP (20mg/kg, i.p. and another dose of 10 mg/kg 6h later). By using the administration protocols described, the anticonvulsant effect of NS1209 was faster and more complete than that of DZP. NS1209 treatment (20 mg/kg bolus followed by 5mg/kg h infusion for 24 h) was neuroprotective against SE-induced hippocampal neurodegeneration, but to a lesser extent than DZP. These findings suggest that AMPA receptor blockade by NS1209 provides a novel and mechanistically complimentary addition to the armamentarium of drugs used to treat SE in humans.

Topics: Amygdala; Animals; Anticonvulsants; Diazepam; Disease Models, Animal; Dose-Response Relationship, Drug; Electric Stimulation; Electroencephalography; Hippocampus; Kainic Acid; Male; Pyrroles; Rats; Rats, Sprague-Dawley; Receptors, AMPA; Status Epilepticus; Tetrahydroisoquinolines; Video Recording