Edaravone ALS Trial

Overview

Edaravone (marketed as Radicava®) is a free radical scavenger that was approved for the treatment of amyotrophic lateral sclerosis (ALS) in Japan (2015), South Korea (2018), and the United States (2017). The pivotal trials demonstrated that edaravone can slow functional decline in a subset of ALS patients with early disease and relatively rapid progression[@edaravone2017].

Edaravone represents one of only two FDA-approved disease-modifying therapies for ALS, alongside riluzole, making it a critical treatment option for patients diagnosed with this progressive neurodegenerative disease.

Trial Details

| Parameter | Value |
|-----------|-------|
| Phase | Phase 3 |
| Status | Approved (2017) |
| Drug | Edaravone (Radicava®) |
| Dosage | 60 mg IV infusion daily |
| Patient Population | Adults with ALS |
| Treatment Cycle | 28 days on, 28 days off |
| ClinicalTrials.gov Identifier | NCT01492686 |
| Sponsor | Mitsubishi Tanabe Pharma |

Mechanism of Action

Edaravone works through multiple neuroprotective pathways that address the key pathological mechanisms underlying ALS[@edaravone2019]:

Antioxidant Effects

Overview

Edaravone (marketed as Radicava®) is a free radical scavenger that was approved for the treatment of amyotrophic lateral sclerosis (ALS) in Japan (2015), South Korea (2018), and the United States (2017). The pivotal trials demonstrated that edaravone can slow functional decline in a subset of ALS patients with early disease and relatively rapid progression[@edaravone2017].

Edaravone represents one of only two FDA-approved disease-modifying therapies for ALS, alongside riluzole, making it a critical treatment option for patients diagnosed with this progressive neurodegenerative disease.

Trial Details

| Parameter | Value |
|-----------|-------|
| Phase | Phase 3 |
| Status | Approved (2017) |
| Drug | Edaravone (Radicava®) |
| Dosage | 60 mg IV infusion daily |
| Patient Population | Adults with ALS |
| Treatment Cycle | 28 days on, 28 days off |
| ClinicalTrials.gov Identifier | NCT01492686 |
| Sponsor | Mitsubishi Tanabe Pharma |

Mechanism of Action

Edaravone works through multiple neuroprotective pathways that address the key pathological mechanisms underlying ALS[@edaravone2019]:

Antioxidant Effects

• Free Radical Scavenging: Edaravone directly neutralizes peroxyl radicals and other reactive oxygen species that accumulate in ALS patients
• Lipid Peroxidation Prevention: Inhibits lipid oxidation cascades that damage neuronal membranes
• Oxidative Stress Reduction: Reduces overall oxidative burden in motor neurons
• Neuroinflammation Modulation: Attenuates inflammatory responses that contribute to neurodegeneration

Neuroprotective Mechanisms

• Neuronal Survival: Protects motor neurons from oxidative damage-induced death
• Axonal Integrity: Preserves axonal structure and function
• Mitochondrial Protection: Helps maintain mitochondrial function under oxidative stress
• Protein Aggregation Reduction: May reduce formation of aberrant protein aggregates

Cellular Protection

The drug's ability to cross the blood-brain barrier allows it to directly protect motor neurons in the central nervous system. Research suggests edaravone may work through:

• Upregulation of neurotrophic factors
• Inhibition of inducible nitric oxide synthase (iNOS)
• Reduction of caspase-3 activation
• Modulation of the Nrf2-ARE pathway

Clinical Trial Program

Pivotal Studies

The clinical development program included multiple randomized, double-blind, placebo-controlled trials:

MCI-186-1 (Japanese Confirmatory Trial)

• Design: 24-week treatment period
• Population: 137 ALS patients
• Primary Endpoint: Change in ALSFRS-R score
• Result: Significant benefit in functional decline

MCI-186-2 (US Trial)

• Design: 24-week treatment
• Population: Similar to Japanese trial
• Result: Mixed results, led to post-hoc analysis

Post-hoc Analysis

A critical post-hoc analysis identified a subgroup of patients who showed the strongest response to edaravone:

• Disease duration ≤ 2 years
• Forced vital capacity (FVC) ≥ 80%
• Definite or probable ALS by El Escorial criteria

Results

Key Findings

• Functional Decline: 33% slower progression in treated patients vs placebo[@edaravone2017]
• Response Rate: Most pronounced benefit in early, rapidly progressing patients
• Survival Trend: Non-significant trend toward improved survival
• Safety Profile: Generally well-tolerated with manageable side effects

Efficacy by Subgroup

| Patient Group | Treatment Effect |
|--------------|-----------------|
| All patients | Modest benefit (not significant) |
| Early disease, fast progression | Significant benefit (p=0.013) |
| Later disease | No significant benefit |

Adverse Effects

• Injection Site Reactions: Common with IV infusion (soreness, irritation)
• Gastrointestinal: Nausea, vomiting, decreased appetite
• Headache: Mild to moderate
• Dizziness: Occasionally reported
• Rash: Rare allergic reactions

FDA Approval and Clinical Use

Approval History

• Japan: June 2015 (first global approval)
• South Korea: November 2018
• United States: May 2017 (FDA approval)
• European Union: Not approved (as of 2024)

Dosing Regimen

The FDA-approved dosing schedule:

Patient Selection

Clinical practice guidelines recommend edaravone for:

• Patients within 2 years of symptom onset
• Patients with relatively preserved respiratory function
• Patients showing rapid progression
• Those without significant comorbidities

Clinical Significance

Impact on ALS Treatment

Edaravone established several important precedents[@yoshino2018]:

Current Practice

As of 2024, edaravone is used in clinical practice alongside:

• Riluzole (first approved ALS drug)
• Sodium phenylbutyrate/taurursodiol (AMX0035, approved 2022)
• Tofersen (for SOD1 mutations, approved 2023)
• Various symptomatic treatments

Ongoing Research

Long-term studies continue to evaluate[@takahashi2021]:

• Extended safety over multiple years
• Combination therapy with other ALS drugs
• Biomarkers predicting response
• Benefits in different ALS phenotypes

Related Pages

• [Amyotrophic Lateral Sclerosis](/diseases/amyotrophic-lateral-sclerosis)
• [Riluzole](/therapeutics/riluzole)
• [Oxidative Stress in Neurodegeneration](/mechanisms/oxidative-stress)
• [ALS Treatment Pipeline](/clinical-trials/als-treatment-pipeline)

References

Pathway Diagram

The following diagram shows key molecular relationships for Edaravone ALS Trial based on knowledge graph edges:

Related Hypotheses

From the [SciDEX Exchange](/exchange) — scored by multi-agent debate

• [Stress Granule Phase Separation Modulators](/hypothesis/h-97aa8486) — <span style="color:#81c784;font-weight:600">0.71</span> · Target: G3BP1
• [Heat Shock Protein 70 Disaggregase Amplification](/hypothesis/h-5dbfd3aa) — <span style="color:#81c784;font-weight:600">0.71</span> · Target: HSPA1A
• [PARP1 Inhibition Therapy](/hypothesis/h-69919c49) — <span style="color:#81c784;font-weight:600">0.67</span> · Target: PARP1
• [Cryptic Exon Silencing Restoration](/hypothesis/h-4fabd9ce) — <span style="color:#81c784;font-weight:600">0.66</span> · Target: TARDBP
• [Arginine Methylation Enhancement Therapy](/hypothesis/h-19003961) — <span style="color:#81c784;font-weight:600">0.65</span> · Target: PRMT1
• [Cross-Seeding Prevention Strategy](/hypothesis/h-eea667a9) — <span style="color:#81c784;font-weight:600">0.65</span> · Target: TARDBP
• [RNA Granule Nucleation Site Modulation](/hypothesis/h-fffd1a74) — <span style="color:#81c784;font-weight:600">0.64</span> · Target: G3BP1
• [Axonal RNA Transport Reconstitution](/hypothesis/h-8196b893) — <span style="color:#81c784;font-weight:600">0.63</span> · Target: HNRNPA2B1

Related Analyses:

• [TDP-43 phase separation therapeutics for ALS-FTD](/analysis/SDA-2026-04-01-gap-006) &#x1f504;
• [RNA binding protein dysregulation across ALS FTD and AD](/analysis/SDA-2026-04-01-gap-v2-68d9c9c1) &#x1f504;

Pathway Diagram

The following diagram shows the key molecular relationships involving Edaravone ALS Trial discovered through SciDEX knowledge graph analysis: