Target: GLP-1 receptor (GLP-1R)
Approach: Repurpose GLP-1 receptor agonists (liraglutide, semaglutide, dulaglutide, exenatide) for neuroprotection in AD, PD, and aging
Therapeutic Area: Alzheimer's Disease, Parkinson's Disease, ALS, Aging-linked Cognitive Decline
Score: 78/100
GLP-1 (glucagon-like peptide-1) is an incretin hormone secreted from intestinal L-cells in response to food intake. Beyond its well-established role in glucose homeostasis, GLP-1 exerts direct neuroprotective effects through receptor-mediated signaling in the central nervous system[1][2].
Key GLP-1 effects in the brain:
GLP-1 receptor agonists have demonstrated neuroprotective potential in multiple preclinical models of neurodegeneration:
Alzheimer's Disease:
Parkinson's Disease:
ALS:
GLP-1 receptors are expressed in:
The blood-brain barrier permeability varies by compound:
| Dimension | Score | Rationale |
|---|---|---|
| Novelty | 7 | Repurposing of approved diabetes drugs; new for neurodegeneration |
| Mechanistic Rationale | 8 | Strong preclinical data; multiple neuroprotective pathways |
| Root-Cause Coverage | 7 | Addresses metabolic dysfunction, neuroinflammation, proteostasis |
| Delivery Feasibility | 9 | Approved drugs with established manufacturing; injectable/formulation challenges |
| Safety Plausibility | 9 | extensive safety data from diabetes indications |
| Combinability | 8 | Works with insulin, NAD+ boosters, autophagy enhancers |
| Biomarker Availability | 8 | GLP-1 levels, blood glucose, cognitive batteries, CSF markers |
| De-risking Path | 8 | Already approved; repurposing pathway is faster |
| Multi-disease Potential | 9 | Strong rationale for AD, PD, ALS, vascular dementia |
| Patient Impact | 8 | Large patient populations could benefit; improves comorbidities |
Total: 78/100
Liraglutide:
Exenatide:
GLP-1 agonists synergize with:
| Risk | Mitigation |
|---|---|
| Limited BBB penetration | Use high-dose or CNS-optimized formulations |
| GI side effects | Start low, titrate slowly |
| Pancreatitis risk | Monitor pancreatic enzymes |
| Variable response | Biomarker-guided patient selection |
BBB Penetration Optimization: Compare CNS exposure of semaglutide, liraglutide, and novel GLP-1/GIP dual agonists in wild-type and 5xFAD mice using LC-MS/MS. Test high-dose protocols to establish dose-response for brain penetration.
Motor Neuron Protection Assay: Test GLP-1 agonists in SOD1 G93A iPSC-derived motor neurons. Measure survival, neurite length, and electrophysiological function. Include GLP-1/GIP dual agonists for comparison.
Alpha-Synuclein Aggregation Model: Evaluate exenatide and semaglutide in preformed fibril (PFF) mouse models. Assess alpha-synuclein phosphorylation, fibril recruitment, and behavioral outcomes.
Biomarker Correlation Study: Establish CSF and blood biomarkers (NfL, p-tau181, GLP-1 levels) in existing clinical samples from completed trials. Correlate with cognitive/motor outcomes.
Enrichment Strategy: Focus on early-stage patients (AD: MMSE 20-26, PD: Hoehn-Yahr 1-2) with confirmed biomarker positivity (CSF p-tau181 for AD, alpha-synuclein seeds for PD).
Dose-Finding Design: Start with approved diabetes doses, escalate to 2-3x for CNS optimization. Use adaptive design with biomarker interim analysis.
Endpoints:
Combination Protocol: Design add-on to standard care (donepezil for AD, dopaminergic therapy for PD). Include exploratory arm with intranasal insulin combination.
Novo Nordisk: Leverage existing GLP-1 franchise (semaglutide, liraglutide). Partner for CNS-specific formulation development and clinical trials.
Eli Lilly: Access tirzepatide (GLP-1/GIP dual agonist) and negotiate CNS-optimized formulation partnership.
Biogen: Partner for Alzheimer's combination trials with lecanemab or other anti-amyloid agents.
Michael J. Fox Foundation: Fund PD-specific clinical trials with GLP-1 agonists. Leverage existing trial infrastructure.
Academic Consortium: ADCS (Alzheimer's Disease Cooperative Study) and PD trials networks for operational efficiency.
| Milestone | Timeline | Cost |
|---|---|---|
| BBB penetration study in rodents | Months 1-4 | $350K |
| iPSC motor neuron assay setup | Months 3-6 | $280K |
| GLP-1/GIP dual agonist comparison | Months 4-8 | $320K |
| CSF biomarker assay validation | Months 6-10 | $200K |
| IND-enabling toxicology planning | Months 9-12 | $250K |
Estimated Phase 1 Cost: $1.4M
| Milestone | Timeline | Cost |
|---|---|---|
| AD Phase 2a trial (semaglutide) | Months 10-24 | $3.2M |
| PD Phase 2 trial (exenatide) | Months 12-26 | $2.8M |
| Biomarker integration | Months 14-28 | $450K |
| Interim analysis & dose selection | Months 24-30 | $350K |
Estimated Phase 2 Cost: $6.8M
| Milestone | Timeline | Cost |
|---|---|---|
| AD Phase 3 registration trial | Months 28-48 | $18M |
| PD Phase 3 registration trial | Months 30-50 | $15M |
| Combination therapy trial | Months 36-54 | $8M |
| Regulatory filings | Months 48-54 | $2M |
Estimated Phase 3 Cost: $43M
| Scenario | Probability | Adjusted Cost |
|---|---|---|
| Optimistic (both Phase 3 succeed) | 25% | $51M |
| Base case (one indication succeeds) | 45% | $42M |
| Conservative (repurposing only) | 30% | $25M |
| Gate | Criteria | Go/No-Go |
|---|---|---|
| Phase 1 → 2 | BBB exposure confirmed, biomarker assay validated | Go if GLP-1 detectable in CSF at therapeutic doses |
| Phase 2 → 3 (AD) | Signal in cognitive endpoint, biomarker reduction | Go if ADAS-Cog benefit ≥2 points vs. placebo |
| Phase 2 → 3 (PD) | Motor score improvement ≥3 points | Go if MDS-UPDRS benefit ≥3 points vs. placebo |
Hölscher C. Novel dual GLP-1/GIP receptor agonists are neuroprotective in mouse models of Alzheimer's disease. Journal of Alzheimer's Disease. 2014. ↩︎
Athauda D, Foltynie T. Glucagon-like peptide 1 receptor agonists for neuroprotection in Parkinson's disease. Current Neurology and Neuroscience Reports. 2017. ↩︎