Pharmacokinetics of Edaravone Oral Suspension in Patients With Amyotrophic Lateral Sclerosis

PURPOSE

Edaravone is a neuroprotective agent approved as an intravenous treatment for amyotrophic lateral sclerosis (ALS). The intravenous administration of edaravone places a burden on patients and there is a clinical need for oral agents for the treatment of ALS. This report aimed to assess the pharmacokinetics and safety of an edaravone oral suspension in patients with ALS after oral and percutaneous endoscopic gastrostomy (PEG) tube administration.

METHODS

Two single-dose, open-label phase 1 clinical studies were conducted. Edaravone oral suspension (105 mg of edaravone in 5 mL aqueous suspension) was administered orally and via PEG tube to 9 and 6 Japanese patients with ALS, respectively. Plasma and urinary pharmacokinetics of unchanged edaravone and its metabolites (sulfate and glucuronide conjugates) were determined. Safety was also evaluated.

FINDINGS

After reaching maximum plasma concentration, the mean plasma concentration-time of unchanged edaravone showed a triphasic elimination. Mean plasma concentration-time profiles of the metabolites were higher than those of unchanged edaravone. The mean urinary excretion ratios were higher for the glucuronide conjugate than for either unchanged edaravone or the sulfate conjugate. In patients administered edaravone orally, a single adverse event occurred (blood urine present), which was mild and improved without medical intervention. No adverse drug reactions or serious adverse events were reported. In patients administered edaravone via PEG tube, 5 treatment-emergent adverse events were reported in 3 patients; none were related to the study drug. No adverse drug reactions were reported.

IMPLICATIONS

In patients with ALS, a single dose of edaravone oral suspension was well absorbed and mainly eliminated in urine as the glucuronide conjugate. No safety concerns emerged. Pharmacokinetics were similar to those previously reported in healthy participants following oral administration. This indicates that effective drug concentrations were achieved and edaravone can be successfully administered both orally and via a PEG tube in patients with ALS.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, NCT04176224 (oral administration) and NCT04254913 (PEG tube administration), www.

CLINICALTRIALS

gov.

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.

Intranasal administration of edaravone nanoparticles improves its stability and brain bioavailability

The clinical application of EDV, a potent antioxidant drug approved for amyotrophic lateral sclerosis (ALS), is limited by its short biological half-life and poor water solubility necessitating hospitalization during intravenous infusion. Nanotechnology-based drug delivery constitutes a powerful tool through inferring drug stability and targeted drug delivery improving drug bioavailability at the diseased site. Nose-to-brain drug delivery offers direct access to the brain bypassing the blood brain barrier and reducing systemic biodistribution. In this study, we designed EDV-loaded poly(lactic-co-glycolic acid) (PLGA)-based polymeric nanoparticles (NP-EDV) for intranasal administration. NPs were formulated by the nanoprecipitation method. Morphology, EDV loading, physicochemical properties, shelf-life stability, in vitro release and pharmacokinetic assessment in mice were conducted. EDV was efficiently loaded into ∼90 nm NPs, stable up to 30 days of storage, at ∼3% drug loading. NP-EDV reduced H2O2-induced oxidative stress toxicity in mouse microglial cell line BV-2. Optical imaging and ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) showed that intranasal delivery of NP-EDV offered higher and more sustained brain uptake of EDV compared to intravenous administration. This study is the first of its kind to develop an ALS drug in a nanoparticulate formulation for nose-to-brain delivery raising hope to ALS patients where currently treatment options are limited to two clinically approved drugs only.

CNM-Au8: an experimental agent for the treatment of amyotrophic lateral sclerosis (ALS)

INTRODUCTION

Two established disease-specific therapies for the treatment of amyotrophic lateral sclerosis (ALS) are riluzole and edaravone. Limitations of these medications include minimal progression slowing or survival benefit, and effectiveness only in selected populations, particularly for edaravone. AMX0035 and tofersen received US FDA approval in September 2022 and April 2023, respectively. However, phase 3 trials, further examining both medications' efficacy, are ongoing. CNM-Au8 is an efficient catalyst of energy metabolism and is therefore a potential disease-modifying treatment for ALS, a neurodegenerative condition in which there is bioenergetics impairment.

AREAS COVERED

In this review, we provide an overview of the current ALS treatment market, followed by a description of the pharmacodynamics and pharmacokinetics of CNM-Au8. The main preclinical and available early clinical evidence of CNM-Au8 is then described, as well as its potential as an ALS treatment.

EXPERT OPINION

Oral treatment with CNM-Au8 failed to meet primary clinical and electrodiagnostic endpoints in phase 2/3 clinical trials. Despite this failure, a number of exploratory endpoints included in phase 2/3 trials suggest CNM-Au8 has the potential to significantly slow clinical worsening, improve quality of life, and prolong survival in ALS. Further study of CNM-Au8 in a phase 3 clinical trial is currently underway.

Open-label, Single-dose Studies of the Pharmacokinetics of Edaravone in Subjects with Mild, Moderate, or Severe Hepatic Impairment Compared to Subjects with Normal Hepatic Functioning

PURPOSE

Two studies were conducted to assess the pharmacokinetic (PK) properties and tolerability of edaravone in Japanese subjects with mild to moderate hepatic impairment or normal hepatic functioning (study 1), and in white subjects with severe hepatic impairment compared to subjects with normal hepatic functioning (study 2).

METHODS

Studies 1 and 2 were multicenter, open-label, single-dose studies that included subjects aged 18-75 years. In study 1, subjects were stratified into 3 different groups of hepatic functioning according to Child-Pugh score: mild hepatic impairment, score 5 or 6 (n = 8); moderate hepatic impairment, score 7-9 (n = 6); or normal hepatic functioning (n = 8). In study 2, subjects had severe hepatic impairment (Child-Pugh score 10-14; n = 6) or normal hepatic functioning (n = 6). In both studies, all subjects were given edaravone 30 mg IV infused over 60 min on the morning of day 1. Blood samples for use in PK analyses were collected from days 1-3. The PK properties (C_max, AUC_0-last, and AUC_0-∞) of edaravone and its sulfate conjugate metabolite were measured.

FINDINGS

In study 1, the geometric least-squares mean (GLSM) C_max and AUC_0-∞ of unchanged edaravone were 1.203- and 1.065-fold greater, respectively, in subjects with mild hepatic impairment versus normal hepatic functioning, and were 1.235- and 1.142-fold greater, respectively, in subjects with moderate hepatic impairment versus normal hepatic functioning. In study 2, GLSM C_max and AUC_0-∞ of unchanged edaravone were 1.203- and 1.190-fold greater, respectively, in subjects with severe hepatic impairment versus normal hepatic functioning. In both studies the AUC_0-last, AUC_0-∞, unbound AUC from time zero to infinity, and C_max of unchanged edaravone were increased slightly with increases in Child-Pugh classification. No adverse events considered related to edaravone were reported, except for 1 case of sinus bradycardia in a subject with normal hepatic functioning in study 2. The event was moderate in severity, considered as possibly related to edaravone, and resolved during the study.

IMPLICATIONS

Mild to moderate and severe hepatic impairment had no apparent clinically significant effects on the PK profile of edaravone in Japanese and white subjects, respectively, relative to individuals with normal hepatic functioning, and there were no notable tolerability concerns. Thus, edaravone dosage adjustments are unlikely to be needed in edaravone-treated patients with mild to moderate and severe hepatic impairment. ClinicalTrials.gov identifiers: NCT03289234 (mild to moderate hepatic impairment) and NCT03664544 (severe hepatic impairment).

Simultaneous Blood-Brain Barrier Crossing and Protection for Stroke Treatment Based on Edaravone-Loaded Ceria Nanoparticles

Cerebral vasculature and neuronal networks will be largely destroyed due to the oxidative damage by overproduced reactive oxygen species (ROS) during a stroke, accompanied by the symptoms of ischemic injury and blood-brain barrier (BBB) disruption. Ceria nanoparticles, acting as an effective and recyclable ROS scavenger, have been shown to be highly effective in neuroprotection. However, the brain access of nanoparticles can only be achieved by targeting the damaged area of BBB, leading to the disrupted BBB being unprotected and to turbulence of the microenvironment in the brain. Nevertheless, the integrity of the BBB will cause very limited accumulation of therapeutic nanoparticles in brain lesions. This dilemma is a great challenge in the development of efficient stroke nanotherapeutics. Herein, we have developed an effective stroke treatment agent based on monodisperse ceria nanoparticles, which are loaded with edaravone and modified with Angiopep-2 and poly(ethylene glycol) on their surface (E-A/P-CeO₂). The as-designed E-A/P-CeO₂ features highly effective BBB crossing via receptor-mediated transcytosis to access brain tissues and synergistic elimination of ROS by both the loaded edaravone and ceria nanoparticles. As a result, the E-A/P-CeO₂ with low toxicity and excellent hemo/histocompatibility can be used to effectively treat strokes due to great intracephalic uptake enhancement and, in the meantime, effectively protect the BBB, holding great potentials in stroke therapy with much mitigated harmful side effects and sequelae.