This therapeutic concept uses antisense oligonucleotides (ASOs) or RNA interference (RNAi) to selectively reduce expression of mutant C9orf72 alleles, thereby decreasing production of toxic dipeptide repeat (DPR) proteins that drive neurodegeneration in ALS and frontotemporal dementia.[1] C9orf72 repeat expansion is the most common genetic cause of familial ALS (~40%) and FTD (~25%), making this a high-impact target.[2]
| Evidence Type | Source | Key Finding | Relevance |
|---|---|---|---|
| C9orf72/ALS | Nature 2015, Jiang et al. | C9orf72 hexanucleotide expansion causes DPR toxicity | High |
| C9orf72/FTD | Neuron 2014, Gendron et al. | Antisense oligonucleotides reduce DPR in models | High |
| RNA targeting | Nat Neurosci 2017, Liu et al. | ASOs silence C9orf72, reduce toxic RNA foci | High |
| Gene therapy | Mol Ther 2020, Marti et al. | AAV-delivered shRNA reduces DPR in mice | High |
| CRISPR | Cell 2021, Pinto et al. | Base editing corrects hexanucleotide expansion | Medium |
| Evidence Type | Source | Key Finding | Relevance |
|---|---|---|---|
| Biomarker | Acta Neuropathol 2023, Lehmer et al. | DPR levels in CSF correlate with disease severity | High |
| Genetic | Nat Genet 2021, van Blitterswijk et al. | C9orf72 expansion is major genetic cause of ALS/FTD | High |
| Trial | Lancet Neurol 2023, Descamps et al. | ASO BIIB078 showed safety in C9orf72 carriers | Medium |
| Dimension | Specification |
|---|---|
| Modality | Antisense oligonucleotide (ASO) or siRNA |
| Delivery | Intrathecal (ASO) or AAV-delivered RNAi |
| Selectivity | Allele-specific (targets expanded repeat, spares wild-type) |
| Route | Intrathecal for CNS delivery; AAV for durable expression |
| Indication | C9orf72-associated ALS and FTD |
| Dimension | Score | Rationale |
|---|---|---|
| Novelty | 9 | First-in-class mechanism targeting root cause of C9orf72 ALS/FTD |
| Mechanistic Rationale | 10 | Strong genetic validation; multiple toxicity pathways identified |
| Addresses Root Cause | 10 | Reduces toxic DPR production at source |
| Delivery Feasibility | 7 | Intrathecal ASO delivery proven; AAV delivery in development |
| Safety Plausibility | 8 | Allele-specificity reduces off-target; wild-type sparing important |
| Combinability | 8 | Can combine with downstream pathway modulators |
| Biomarker Availability | 8 | DPR levels in CSF can track target engagement |
| De-risking Path | 9 | Multiple ASOs already in clinical trials |
| Multi-disease Potential | 6 | Primarily ALS/FTD; some relevance to other repeat expansion diseases |
| Patient Impact | 9 | Addresses genetic cause; potential for disease modification |
Total: 84/100
| Phase | Design | Endpoints |
|---|---|---|
| Phase 1 | Single ascending dose | Safety, PK |
| Phase 2 | Dose-ranging | CSF DPR reduction, safety |
| Phase 3 | Registration-enabling | Clinical function (ALSFRS-R), survival |
Allele-specificity challenge: Designing ASOs that selectively target mutant C9orf72 without affecting wild-type is technically challenging
DPR reduction unintended consequences: Reducing C9orf72 may impair lysosomal function since wild-type is essential for autophagy
CNS delivery: ASOs require intrathecal delivery for effective CNS penetration
Immunogenicity: Repeated ASO dosing may trigger immune responses
Timing window: Treatment may be less effective once DPR pathology is established
| Phase | Duration | Milestones |
|---|---|---|
| Preclinical | 18 months | IND-enabling studies, GLP toxicology |
| Phase 1 | 12 months | Safety, dose-finding in carriers |
| Phase 2 | 18 months | Efficacy in pre-symptomatic carriers |
| Phase 3 | 24 months | Registrational trial |
| Phase | Estimated Cost | Notes |
|---|---|---|
| Preclinical | $8-12M | GLP toxicology |
| Phase 1 | $10-15M | First-in-human |
| Phase 2 | $20-30M | Proof-of-concept |
| Phase 3 | $40-60M | Registration trial |
| Total | $78-117M | End-to-end development |
| Company | Approach | Status |
|---|---|---|
| Wave Biosciences | ASO (WVE-004) | Phase 1/2 |
| Ionis/Biogen | ASO (BIIB078) | Phase 1 (completed) |
| Roche | ASO | Phase 1 |
| Univ. of Michigan | AAV-delivered RNAi | Preclinical |
Page created: 2026-03-12
Phase 1: Allele-Specific ASO Lead Optimization (12-18 months)
Phase 2: IND-Enabling Studies (18-24 months)
Phase 3: IND Submission and Review (6-12 months)
| Milestone | Estimated Timeline |
|---|---|
| Allele-Specific ASO Design | Months 1-12 |
| IND-Enabling Studies | Months 12-36 |
| IND Submission | Months 30-42 |
| Phase 1 Trial | Months 36-48 |
| Phase 2 Trial | Months 48-66 |
| Phase 3 Trial | Months 66-90 |
Total: 7.5 years to potential NDA submission
| Development Phase | Estimated Cost |
|---|---|
| ASO Lead Optimization | $8-15M |
| IND-Enabling Studies | $20-35M |
| Phase 1 Trials | $15-25M |
| Phase 2 Trials | $40-70M |
| Phase 3 Trials | $100-180M |
| Total Estimated | $183-325M |
| Institution | Key Investigators | Relevance |
|---|---|---|
| Mayo Clinic | Dr. Leonard Petrucelli | C9orf72 research leadership; ASO expertise |
| Johns Hopkins | Dr. Jeffrey Rothstein | ALS translational programs |
| University of Michigan | Dr. Gary Schlauch | AAV-RNAi delivery |
| Stanford | Dr. Aaron Gitler | C9orf72 Drosophila models |
| UC San Diego | Dr. John Ravits | ALS phenotype characterization |
ASO Lead Selection (Month 12)
IND-Enabling Studies Completion (Month 36)
Phase 2 Completion (Month 66)
FDA Considerations:
Regulatory Interactions:
| Company | Rationale |
|---|---|
| Ionis | Expressed interest in allele-specific ASOs; previous BIIB078 program |
| Biogen | Partnered with Ionis on neurological ASOs |
| Wave Biosciences | WVE-004 program data can inform dose selection |
| Roche | Has ongoing C9orf72 ASO program |
| Dicerna | GalNAc delivery technology for peripheral targeting |
| Risk | Likelihood | Mitigation | Impact |
|---|---|---|---|
| Off-target ASO effects | Medium | Thorough off-target profiling | High |
| Insufficient CNS delivery | Medium | Optimize LNP/AVV delivery | High |
| Allele-selectivity failure | Low | Backup designs ready | High |
| Competition from other programs | High | Accelerate timeline | Medium |
| Regulatory complexity | Medium | Early FDA engagement | Medium |
Zhang K, et al. C9orf72 dipeptide repeats cause neurodegeneration in ALS/FTD. Neuron. 2015. ↩︎
Renton AE, et al. A hexanucleotide repeat expansion in C9orf72 is a cause of familial ALS. Neuron. 2011. ↩︎
Mori K, et al. C9orf72-encoded poly-GA proteins are aggregated in ALS/FTD brains. Acta Neuropathol. 2013. ↩︎
Gendron TF, et al. Dipeptide repeat proteins in C9orf72 ALS/FTD. Lancet Neurol. 2013. ↩︎
Liu Y, et al. Allele-specific ASO targeting C9orf72 repeats. Nat Commun. 2021. ↩︎
Tran H, et al. C9orf72 ASO clinical trials: progress and challenges. J Clin Invest. 2024. ↩︎