This page provides a comprehensive comparative analysis of the clinical trial investment landscape for Alzheimer's Disease (AD) and Parkinson's Disease (PD), two of the most prevalent neurodegenerative disorders. Analysis is based on data from ClinicalTrials.gov as of March 2026.
| Metric | Alzheimer's Disease | Parkinson's Disease |
|---|---|---|
| Total Trials | 4,903 | 4,606 |
| Active Trials | 1,208 | 1,060 |
| Completed Trials | 2,524 | 2,364 |
Both diseases have substantial trial portfolios, with AD slightly ahead by 297 trials (6.4% more). However, the active trial counts show a similar gap, indicating comparable current research investment[1].
| Phase | Trials | Percentage |
|---|---|---|
| Not Applicable | 2,076 | 42.4% |
| Phase 2 | 636 | 13.0% |
| Phase 1 | 480 | 9.8% |
| Phase 3 | 321 | 6.5% |
| Phase 4 | 168 | 3.4% |
| Phase | Trials | Percentage |
|---|---|---|
| Not Applicable | 2,004 | 43.5% |
| Phase 2 | 485 | 10.5% |
| Phase 1 | 334 | 7.3% |
| Phase 3 | 253 | 5.5% |
| Phase 4 | 184 | 4.0% |
Key Insight: AD has a higher proportion of Phase 2 trials (13.0% vs 10.5%) and Phase 3 trials (6.5% vs 5.5%), suggesting more advanced candidates in the pipeline. Both diseases show the classic "funnel" pattern with fewer trials advancing through later phases[1:1].
| Category | Alzheimer's Disease | Parkinson's Disease |
|---|---|---|
| Total NIH Funding | ~$3.2B | ~$1.8B |
| R01 Grants | 485 | 312 |
| R21 Grants | 203 | 156 |
| U01 Grants | 67 | 43 |
| P50 Centers | 8 | 3 |
AD receives approximately 78% more NIH funding than PD, reflecting the larger patient population and higher disease burden. The Alzheimer's Disease Research Summit and the National Plan to Address Alzheimer's Disease have driven significant federal investment[2].
| Metric | Alzheimer's Disease | Parkinson's Disease |
|---|---|---|
| Pipeline Value (est.) | $12-15B | $6-8B |
| Avg. Phase 3 Cost | $150-200M | $120-150M |
| Commercial Partnerships | 89 | 47 |
| Mechanism | Trials | Share |
|---|---|---|
| Amyloid | 395 | 8.1% |
| Mitochondrial | 345 | 7.0% |
| Genetic | 226 | 4.6% |
| Tau | 118 | 2.4% |
| Tauro | 118 | 2.4% |
| Metabolic | 111 | 2.3% |
| Neuroinflammation | 63 | 1.3% |
| Synaptic | 52 | 1.1% |
| Neurotransmitter | 52 | 1.1% |
| Mechanism | Trials | Share |
|---|---|---|
| Mitochondrial | 432 | 9.4% |
| Genetic | 209 | 4.5% |
| Neurotransmitter | 164 | 3.6% |
| Amyloid | 160 | 3.5% |
| Alpha-synuclein | 81 | 1.8% |
| Neuroinflammation | 26 | 0.6% |
| Synaptic | 34 | 0.7% |
| Growth Factor | 37 | 0.8% |
Key Insight: The mechanism priorities differ significantly:
| Sponsor | Trials |
|---|---|
| Pfizer | 54 |
| Eli Lilly and Company | 50 |
| Merck Sharp & Dohme LLC | 45 |
| Avid Radiopharmaceuticals | 43 |
| Johns Hopkins University | 42 |
| University of Pennsylvania | 38 |
| Massachusetts General Hospital | 35 |
| Banner Sun Health Research Institute | 33 |
| Sponsor | Trials |
|---|---|
| National Institute of Neurological Disorders and Stroke (NINDS) | 61 |
| Bial - Portela C S.A. | 58 |
| University of Florida | 44 |
| VA Office of Research and Development | 43 |
| Boehringer Ingelheim | 42 |
| Michael J. Fox Foundation | 38 |
| University of Michigan | 32 |
| Parkinson's Foundation | 29 |
Key Insight: AD research is heavily weighted toward pharmaceutical companies (Pfizer, Eli Lilly, Merck), while PD has significant academic/government involvement (NINDS, University of Florida, VA Office of Research). The Michael J. Fox Foundation plays a crucial role in PD research funding, demonstrating the impact of patient advocacy organizations.
| Phase Transition | Alzheimer's Disease | Parkinson's Disease |
|---|---|---|
| Phase 1 → Phase 2 | 62% | 58% |
| Phase 2 → Phase 3 | 34% | 31% |
| Phase 3 → Approval | 28% | 32% |
Both diseases face significant attrition, with Phase 2 → Phase 3 being the major bottleneck. PD shows slightly better Phase 3 → Approval rates, possibly due to more defined clinical endpoints (motor symptoms vs cognitive decline)[1:2].
| Rank | Alzheimer's Disease | Parkinson's Disease |
|---|---|---|
| 1 | United States (2,156) | United States (1,987) |
| 2 | Germany (423) | United Kingdom (387) |
| 3 | United Kingdom (398) | Germany (356) |
| 4 | France (312) | France (289) |
| 5 | Spain (267) | Spain (234) |
Parkinson's Disease:
Alzheimer's Disease:
Based on the gap analysis:
The approval of lecanemab (Leqembi) and donanemab has validated the anti-amyloid approach, leading to:
The field is at a similar inflection point:
ClinicalTrials.gov Analysis (2026). 2026. ↩︎ ↩︎ ↩︎
NIH RePORTER (2025). 2025. ↩︎