Oral edaravone demonstrated a favorable safety profile in patients with amyotrophic lateral sclerosis after 48 weeks of treatment.

INTRODUCTION/AIMS: An intravenous (IV) formulation of edaravone has been shown to slow the rate of physical functional decline in amyotrophic lateral sclerosis (ALS). An oral suspension formulation of edaravone was recently approved by the United States Food and Drug Administration for use in patients with ALS. This study assessed the safety and tolerability of oral edaravone. METHODS: This global, open-label, phase 3 study evaluated the long-term safety and tolerability of oral edaravone in adults with ALS who had a baseline forced vital capacity ≥70% of predicted and disease duration ≤3 y. The primary safety analysis was assessed at weeks 24 and 48. Patients received a 105-mg dose of oral edaravone in treatment cycles replicating the dosing of IV edaravone. RESULTS: The study enrolled 185 patients (64.3% male; mean age, 59.9 y; mean disease duration, 1.56 y). The most common treatment-emergent adverse events (TEAEs) at week 48 were fall (22.2%), muscular weakness (21.1%) and constipation (17.8%). Serious TEAEs were reported by 25.9% of patients; the most common were worsening ALS symptoms, dysphagia, dyspnea, and respiratory failure. Twelve TEAEs leading to death were reported. Forty-six (24.9%) patients reported TEAEs that were considered related to study drug; the most common were fatigue, dizziness, headache, and constipation. Sixteen (8.6%) patients discontinued study drug due to TEAEs. No serious TEAEs were related to study drug. DISCUSSION: This study indicated that oral edaravone was well tolerated during 48 wk of treatment, with no new safety concerns identified.

Oral Edaravone - Introducing a Flexible Treatment Option for Amyotrophic Lateral Sclerosis.

INTRODUCTION: Amyotrophic lateral sclerosis (ALS) is a progressive and incurable neurodegenerative disease. While pharmacotherapy options remain limited, the Food and Drug Administration (FDA) approved intravenous (IV) and oral edaravone for the treatment of ALS in 2017 and 2022, respectively. With the addition of oral edaravone, patients with ALS may exclusively use oral medications. AREAS COVERED: The authors performed a review of the published literature using the United States (US) National Library of Medicine's PubMed.gov resource to describe the pharmacokinetics, pharmacodynamics, safety, and efficacy of oral edaravone, as well as pertinent completed and ongoing clinical trials, including the oral edaravone clinical trial development program. The clinical profile of oral edaravone is also discussed. EXPERT OPINION: Edaravone has been shown to slow the rate of motor function deterioration experienced by patients with ALS. As the oral formulation has been approved, patients with ALS may use it alone or in combination with other approved therapeutics. Additional clinical trials and real-world evidence are ongoing to gain further understanding of the clinical profile of oral edaravone.

Cannabidiol modulates excitatory-inhibitory ratio to counter hippocampal hyperactivity.

Cannabidiol (CBD), a non-euphoric component of cannabis, reduces seizures in multiple forms of pediatric epilepsies, but the mechanism(s) of anti-seizure action remain unclear. In one leading model, CBD acts at glutamatergic axon terminals, blocking the pro-excitatory actions of an endogenous membrane phospholipid, lysophosphatidylinositol (LPI), at the G-protein-coupled receptor GPR55. However, the impact of LPI-GPR55 signaling at inhibitory synapses and in epileptogenesis remains underexplored. We found that LPI transiently increased hippocampal CA3-CA1 excitatory presynaptic release probability and evoked synaptic strength in WT mice, while attenuating inhibitory postsynaptic strength by decreasing GABAARγ2 and gephyrin puncta. LPI effects at excitatory and inhibitory synapses were eliminated by CBD pre-treatment and absent after GPR55 deletion. Acute pentylenetrazole-induced seizures elevated GPR55 and LPI levels, and chronic lithium-pilocarpine-induced epileptogenesis potentiated LPI's pro-excitatory effects. We propose that CBD exerts potential anti-seizure effects by blocking LPI's synaptic effects and dampening hyperexcitability.

Long-term open-label perampanel: Generalized tonic-clonic seizures in idiopathic generalized epilepsy.

OBJECTIVE: Assess the longer-term efficacy and safety of adjunctive perampanel (up to 12 mg/day) in patients aged ≥12 years with generalized tonic-clonic (GTC) seizures from the Open-label Extension (OLEx) Phase of Study 332 to determine whether responses obtained during the Core Study are maintained during long-term treatment. METHODS: Patients with GTC seizures previously enrolled in a randomized placebo-controlled trial of perampanel could enter an OLEx Phase comprising 6-week blinded conversion (during which patients previously randomized to placebo-switched to perampanel) and up to 136-week maintenance periods (maximum perampanel dose of 12 mg/day). A 4-week follow-up period was completed by all patients after the last on-treatment visit during the OLEx. We assessed seizure frequency outcomes from preperampanel baseline and the Core Study Pre-randomization Phase, retention rates, doses selected, and treatment-emergent adverse events (TEAEs). RESULTS: Overall, 138 patients entered the OLEx. Median percent reductions in GTC seizures per 28 days from preperampanel were 77% (Weeks 1-13) and 90% (Weeks 40-52). Retention rates were 88% (6 months) and 75% (12 months). Seizure-freedom rates were maintained for at least 2 years regardless of prior treatment received during the Core Study. Most common modal daily dose was >4-8 mg/day (n = 93). Across the Core and OLEx Phases, 120 (87%) patients experienced TEAEs; the most common was dizziness. SIGNIFICANCE: Perampanel was generally well-tolerated, and the TEAEs reported here are consistent with the known safety profile of perampanel. Perampanel offers a long-term treatment option for patients (aged ≥12 years) with GTC seizures.

PROVE: Retrospective, non-interventional, Phase IV study of perampanel in real-world clinical care of patients with epilepsy.

OBJECTIVE: To assess retention, dosing, efficacy, and safety of perampanel in a large cohort of patients with epilepsy during routine clinical care. METHODS: PROVE was a retrospective, non-interventional Phase IV study (NCT03208660). Data were obtained retrospectively from the medical records of patients in the United States initiating perampanel after January 1, 2014, according to treating clinicians' recommendation. Retention rate was the primary efficacy endpoint. Secondary efficacy endpoints included median percent changes in seizure frequency per 28 days from baseline, seizure-freedom rate, and overall investigator impression of seizure effect. Safety endpoints included incidence of treatment-emergent adverse events (TEAEs). Efficacy and safety were also assessed according to baseline use of enzyme-inducing antiseizure medications (EIASMs). RESULTS: Overall, 1703 patients were enrolled and included in the Safety Analysis Set (SAS; ≥1 baseline EIASMs, n = 358 [21.0%]; no baseline EIASMs, n = 1345 [79.0%]). Mean (standard deviation [SD]) cumulative duration of exposure to perampanel was 17.4 (15.7) months; mean (SD) daily perampanel dose was 5.6 (2.7) mg. The most frequent perampanel titration intervals were weekly (23.4%) and every 2 weeks (24.7%). Across the SAS, 24-month retention rate was 48.1% (n = 501/1042). Based on overall investigator impression at the end of treatment, 51.9%, 35.8%, and 12.3% of patients in the SAS experienced improvement, no change, or worsening of seizures, respectively. TEAEs occurred in 704 (41.3%) patients; 79 (4.6%) had serious TEAEs. The most common TEAE was dizziness (7.3%). There was some variation in efficacy according to EIASM use, while retention rates and safety were generally consistent. SIGNIFICANCE: In this final analysis of >1700 patients with epilepsy receiving perampanel in routine clinical care, favorable retention and sustained efficacy were demonstrated for ≥12 months.

Effects of subtype-selective group I mGluR antagonists on synchronous activity induced by 4-aminopyridine/CGP 55845 in adult guinea pig hippocampal slices.

Co-application of the convulsant 4-aminopyridine (4-AP) and the GABA(B) receptor antagonist CGP 55845 to adult guinea pig hippocampal slices elicits giant GABA-mediated postsynaptic potentials (GPSPs) and epileptiform discharges. Here we tested the effects of the group I metabotropic glutamate receptor (mGluR) subtype-selective antagonists LY 367385 (mGlu1, 100 microM), MPEP (mGlu5, 10 microM), and MTEP (mGlu5, 500 nM) on this synchronous activity. Electrophysiological field recordings were performed in the CA3 region of hippocampal slices from adult guinea pigs. The mGlu5 receptor antagonists increased GPSP rate, but the mGlu1 receptor antagonist did not. This ability of mGlu5 receptor antagonists to increase the rate of GPSPs indicates that enough endogenous glutamate is released under these conditions to activate group I mGluR; nevertheless, co-application of a mGlu1 receptor antagonist (LY 367385 or JNJ 16259685) and MPEP did not decrease pre-existing epileptiform activity. Furthermore, co-application of LY 367,385 and MPEP did not prevent the emergence of epileptiform activity. When ionotropic glutamate receptor (iGluR) antagonists were present, neither MPEP nor the group I mGluR agonist DHPG changed GPSP rate, suggesting that pyramidal cell-to-interneuron iGluR-mediated synaptic connections are involved in the rate change mechanism. In contrast to the lack of effect of group I mGluR antagonists on epileptiform activity in the 4-AP/CGP 55845 model, group I mGluR antagonists blocked the emergence of longer epileptiform events and decreased the overall amount of synchronous activity in the GABA(A) antagonist/4-AP model. In conclusion, in the 4-AP/CGP 55845 model, enough glutamate was released to activate group I mGluRs and affect GPSP rate via mGlu5 receptors; however, this group I mGluR activation was not required for the generation of the epileptiform activity.

Calmodulin shuttling mediates cytonuclear signaling to trigger experience-dependent transcription and memory.

Learning and memory depend on neuronal plasticity originating at the synapse and requiring nuclear gene expression to persist. However, how synapse-to-nucleus communication supports long-term plasticity and behavior has remained elusive. Among cytonuclear signaling proteins, γCaMKII stands out in its ability to rapidly shuttle Ca2+/CaM to the nucleus and thus activate CREB-dependent transcription. Here we show that elimination of γCaMKII prevents activity-dependent expression of key genes (BDNF, c-Fos, Arc), inhibits persistent synaptic strengthening, and impairs spatial memory in vivo. Deletion of γCaMKII in adult excitatory neurons exerts similar effects. A point mutation in γCaMKII, previously uncovered in a case of intellectual disability, selectively disrupts CaM sequestration and CaM shuttling. Remarkably, this mutation is sufficient to disrupt gene expression and spatial learning in vivo. Thus, this specific form of cytonuclear signaling plays a key role in learning and memory and contributes to neuropsychiatric disease.

Persistent ictal-like activity in rat entorhinal/perirhinal cortex following washout of 4-aminopyridine.

Application of 4-aminopyridine (4-AP, 100µM) in a solution containing 0.6mM Mg(2+) and 1.2mM Ca(2+) to hippocampal-entorhinal-perirhinal slices of adult rat brain induced ictal-like epileptiform activity in entorhinal and perirhinal cortices as revealed by electrophysiological field potential recordings. The ictal-like activity persisted after washing out the 4-AP. This persistence indicated that a change had occurred in the slice so that it was now "epileptic" in the absence of the convulsant 4-AP. Induction of persistent ictal-like activity was dependent upon the concentration of divalent cations during 4-AP exposure; that is, although 4-AP caused ictal-like activity in approximately half the slices in solution containing 1.6mM Mg(2+) and 2.0mM Ca(2+), this ictal-like activity did not persist upon washout of the 4-AP. Expression of the persistent ictal-like epileptiform activity required ionotropic glutamate-mediated synaptic transmission: application of the AMPA/kainate receptor antagonist NBQX after 4-AP washout reduced persistent ictal-like activity, and the combined application of NBQX and the NMDA receptor antagonist d-AP5 completely blocked it. In order to investigate the mechanism of induction of persistent ictal-like activity, several agents were applied before the introduction of 4-AP. Application of d-AP5 did not block the onset of ictal-like activity upon introduction of 4-AP but did prevent the persistence of the ictal-like activity upon washout of the 4-AP. In contrast, induction of persistent ictal-like activity was not prevented by simultaneous application of the group I metabotropic glutamate receptor (mGluR) antagonists LY 367385 and MPEP or by application of the protein synthesis inhibitor cycloheximide. In conclusion, we have characterized a new in vitro model of epileptogenesis in which induction of ictal-like activity is dependent upon NMDA receptor activation but not upon group I mGluR activation or protein synthesis.

Synaptic depolarizing GABA Response in adults is excitatory and proconvulsive when GABAB receptors are blocked.

In the presence of 4-aminopyridine, interneurons fire synchronously, causing giant GABA-mediated postsynaptic potentials (GPSPs; GPSCs in voltage clamp) in CA3 pyramidal cells in hippocampal slices from adult guinea pigs. These triphasic GPSPs are composed of a GABA(A)-mediated hyperpolarizing component, a depolarizing component, and a GABA(B)-mediated hyperpolarizing component. We propose that GABA(B) receptors exert control over the postsynaptic depolarizing GABA response. Microelectrode and cell-attached recordings demonstrated that the mean number of action potentials during the depolarizing component of the GPSP increased dramatically in the presence of the GABA(B) receptor antagonist (2S)-3-[[(1S)-1-(3,4-dichlorophenyl)ethyl]amino-2- hydroxypropyl](phenylmethyl) phosphinic acid (CGP 55845A; P = 0.003 and 0.0005, respectively). Whole cell voltage-clamp recordings showed that the postsynaptic GABA(B) and depolarizing GABA components of the GPSC overlap substantially, allowing the GABA(B)-mediated hyperpolarization to suppress the excitation mediated by the depolarizing GABA component. Further voltage-clamp recordings showed that CGP 55845A increased the duration of the depolarizing GABA component of the GPSC even when the GABA(B) component had already been blocked by internal QX-314, suggesting that CGP 55845A also increased the duration of GABA release. When glutamatergic transmission is intact, GPSPs directly precede epileptiform afterdischarges. We hypothesize that the depolarizing component of the GPSP triggers the epileptiform events and show here that enhancement of the depolarizing component with CGP 55845A increased epileptiform activity. CGP 55845A increased the likelihood of a GPSP triggering an epileptiform event from 32 to 99% (P = 0.0000001), and significantly increased the number of afterdischarges per epileptiform event (P = 0.001). Loss of GABA(B) receptor function is associated with temporal lobe epilepsy in rodents and humans. We show here that GABA(B) receptors exert control over the synaptic depolarizing GABA response and that block of GABA(B) receptors makes the depolarizing GABA response excitatory and proconvulsive.