Amyotrophic Lateral Sclerosis (ALS) Cure Roadmap provides a comprehensive framework for understanding the current state of therapeutic development for ALS, a fatal neurodegenerative disorder characterized by progressive loss of upper and lower motor neurons. This roadmap synthesizes insights from genetic discoveries, molecular pathology, and clinical trials to identify promising routes to disease modification and ultimately a cure.
ALS is part of a broader neurodegenerative spectrum with Frontotemporal Dementia (FTD), with approximately 15% of ALS patients meeting criteria for FTD and up to 50% showing some degree of cognitive or behavioral impairment. This clinical overlap reflects shared molecular mechanisms, particularly TDP-43 pathology and C9orf72 hexanucleotide repeat expansions. [@chen2023]
Related: [ALS Pathway](/mechanisms/als-pathway) | [ALS Knowledge Gaps](/mechanisms/als-knowledge-gaps-ranked) | [FTD Cure Roadmap](/mechanisms/ftd-cure-roadmap) | [Experiment Priority Index](/experiments/experiment-priority-index)
Amyotrophic Lateral Sclerosis (ALS) Cure Roadmap provides a comprehensive framework for understanding the current state of therapeutic development for ALS, a fatal neurodegenerative disorder characterized by progressive loss of upper and lower motor neurons. This roadmap synthesizes insights from genetic discoveries, molecular pathology, and clinical trials to identify promising routes to disease modification and ultimately a cure.
ALS is part of a broader neurodegenerative spectrum with Frontotemporal Dementia (FTD), with approximately 15% of ALS patients meeting criteria for FTD and up to 50% showing some degree of cognitive or behavioral impairment. This clinical overlap reflects shared molecular mechanisms, particularly TDP-43 pathology and C9orf72 hexanucleotide repeat expansions. [@chen2023]
Related: [ALS Pathway](/mechanisms/als-pathway) | [ALS Knowledge Gaps](/mechanisms/als-knowledge-gaps-ranked) | [FTD Cure Roadmap](/mechanisms/ftd-cure-roadmap) | [Experiment Priority Index](/experiments/experiment-priority-index)
| Treatment | Mechanism | Indication | Efficacy |
|-----------|-----------|------------|----------|
| Riluzole | Glutamate modulation, anti-excitotoxicity | ALS | Modest survival benefit (2-3 months) [@van2017] |
| Edaravone | Antioxidant, anti-oxidative stress | ALS (Japan/US) | Slows functional decline in early-stage patients |
| Tofersen (AMIAS) | SOD1 ASO | SOD1-associated ALS | Significant SOD1 reduction, clinical benefit in fast-progressors |
| Relyvrio (Sodium phenylbutyrate/taurursodiol) | Antioxidant, autophagy induction | ALS | Modest functional benefit |
Approximately 10-15% of ALS cases are familial, with the major genetic causes being:
| Gene | Protein | Pathology | % of Familial ALS | Therapeutic Approach |
|------|---------|-----------|-------------------|---------------------|
| C9orf72 | C9orf72 protein | TDP-43 + DPR | ~40% | ASOs targeting repeat expansion, gene therapy |
| SOD1 | Superoxide dismutase 1 | SOD1 aggregates | ~20% | ASOs (tofersen approved), gene therapy |
| FUS | Fused in sarcoma | FUS aggregates | ~5% | RNA targeting, autophagy modulators |
| TARDBP | TDP-43 | TDP-43 aggregates | ~5% | Splicing modulators, autophagy enhancers |
| VCP | Valosin-containing protein | TDP-43 | ~5% | Autophagy modulators |
| TBK1 | TANK-binding kinase 1 | TDP-43 | ~3% | Autophagy and neuroinflammation targeting |
The identification of these genetic drivers has enabled precision medicine approaches that are now entering clinical trials.
| Mechanism | Therapeutic Target | Status |
|-----------|-------------------|--------|
| TDP-43 pathology | Aggregation inhibitors, autophagy enhancers | Preclinical/Phase 1 |
| Neuroinflammation | TREM2 agonists, CSF1R inhibitors, anti-inflammatory | Phase 1/2 |
| Oxidative stress | Antioxidants (edaravone approved), NRF2 activators | Approved/Phase 2 |
| Excitotoxicity | AMPA/kainate receptor antagonists, glutamate modulation | Approved (riluzole) |
| Mitochondrial dysfunction | Mitochondrial protectants, mitophagy enhancers | Preclinical/Phase 1 |
| Axonal transport defects | Microtubule stabilizers, transport enhancers | Preclinical |
| Metabolic dysfunction | Metabolic modulators, energetic enhancers | Phase 2 |
Goal: Accurate genetic diagnosis, symptom optimization, biomarker baseline
| Action | Status | Timeline |
|--------|--------|----------|
| Confirmatory genetic testing (C9orf72, SOD1, FUS panel) | Available | Week 1 |
| Baseline neurological exam (ALSFRS-R, force vital capacity) | Standard of care | Week 1 |
| Blood biomarker panel (NfL, pNfH, GFAP) | Available | Week 1 |
| Electromyography (EMG) for diagnosis confirmation | Standard of care | Week 1-2 |
| Genetic counseling for family members | Standard of care | Week 2 |
| Riluzole initiation | FDA approved | Week 1 |
| Edaravone initiation (if eligible) | FDA approved | Week 2 |
| Multidisciplinary care (neurology, pulmonology, PT, OT, speech) | Standard of care | Ongoing |
| Non-invasive ventilation (if FVC < 80%) | Standard of care | As needed |
Understanding gaps at this phase:
Goal: Slow or halt disease progression through targeted therapies
C9orf72 hexanucleotide repeat expansion is the most common genetic cause of ALS/FTD. Two pathological mechanisms require targeting:
| Agent | Company | Mechanism | Trial Status | Expected Data |
|-------|---------|-----------|--------------|---------------|
| WVE-004 | Wave Life Sciences | C9orf72 ASO (repeat-containing) | Phase 1/2 (on hold) | Paused - strategic decision |
| BIIB078 | Biogen | C9orf72 ASO | Phase 1 (discontinued) | No clinical benefit |
| ASO-mediated | Various | Allele-selective | Preclinical | 2027+ |
Key learnings: C9orf72 ASO programs have faced challenges - the goal is to reduce toxic RNA species while preserving protein expression. Current approaches may require optimization for brain penetration and delivery.
| Agent | Company | Mechanism | Trial Status | Expected Data |
|-------|---------|-----------|--------------|---------------|
| Tofersen (BIIB067) | Biogen/Ionis | SOD1 ASO | Approved (2023) | Ongoing extension study |
| Ionis-SOD1Rx | Ionis | SOD1 ASO | Phase 1 (completed) | Safety established |
| AAV-SOD1 | Various | Gene therapy | IND-enabling | 2026-2027 |
Key learnings from tofersen: Significant SOD1 reduction in CSF, clinical benefit in patients with faster progression. Early intervention may be critical.
TDP-43 pathology is present in 97% of ALS cases. Novel approaches include:
| Target | Approach | Status |
|--------|----------|--------|
| TREM2 | Agonists to enhance microglial clearance | Phase 1 (AD) |
| CSF1R | Inhibitors to modulate microglia | Phase 2 |
| IL-6 | Anti-IL-6 receptor antibodies | Phase 2 |
Goal: Multi-target intervention tailored to individual patient biology
Given ALS's complex pathophysiology, combining multiple mechanisms may provide synergistic benefit:
| Combination | Rationale | Status |
|-------------|-----------|--------|
| ASO + Neuroinflammation modulator | Target genetic cause + downstream inflammation | Preclinical |
| Anti-excitotoxicity + Antioxidant | Riluzole + Edaravone synergy | Phase 2 |
| Autophagy enhancer + TDP-43 inhibitor | Enhance aggregate clearance | Preclinical |
| Gene therapy + Small molecule | Genetic targeting + pathway modulation | Preclinical |
Goal: Prevent disease onset in at-risk individuals
| Biomarker | Target | Status | Utility |
|-----------|--------|--------|---------|
| NfL | Neurofilament light chain | Validated | Disease progression, prognosis |
| pNfH | Phosphorylated neurofilament heavy | Validated | Disease progression |
| GFAP | Glial fibrillary acidic protein | Clinical | Astrocyte activation |
| TDP-43 | TDP-43 in CSF | Research | Pathology burden |
| SOD1 | SOD1 in CSF | Validated | Target engagement (SOD1) |
| Modality | Target | Status | Utility |
|----------|--------|--------|---------|
| MRI | Cortical thinning, white matter integrity | Standard | Disease progression |
| PET (FDG) | Metabolic patterns | Clinical | FTD overlap |
| PET (Pittsburgh B) | Neuroinflammation | Research | Microglial activation |
| Gap | Priority | Therapeutic Impact |
|-----|----------|-------------------|
| C9orf72 DPR toxicity mechanism | High | Target identification |
| TDP-43 propagation mechanism | High | Biomarker, therapy |
| Selective motor neuron vulnerability | High | Prevention target |
| Microglia-neuron interaction | Medium | Immunotherapy |
| Non-motor neuron contributions | Medium | Broader therapy |
| Environmental risk factors | Medium | Prevention |