Prevention trials
Drug trials before symptoms
Trials that treat people who have Alzheimer’s changes, or very high genetic risk, before memory problems begin. Ongoing trials first.
| Trial | Drug | Who | Status and result |
|---|---|---|---|
| TRAILBLAZER-ALZ 3 | Donanemab | About 3,000 cognitively unimpaired adults with Alzheimer’s pathology | Fully enrolled Primary completion expected October 2027. |
| AHEAD 3-45 | Lecanemab | About 1,400 adults with amyloid but no symptoms | Fully enrolled Primary completion expected December 2028. |
| HT-4253 | Oral LRRK2 inhibitor | 112 biomarker-positive APOE4 carriers in Abu Dhabi | Recruiting 48-week Phase 2a, started May 2026. |
| A4 Study | Solanezumab | More than 1,100 adults with amyloid but no symptoms | No benefit Did not slow cognitive decline. ↗ |
| API Colombia | Crenezumab | 252 members of a Colombian family with an early-onset PSEN1 mutation | No significant benefit Numerical trends favoured the drug, none significant (2022). ↗ |
| Generation Study 1 | Umibecestat or CAD106 | Cognitively unimpaired APOE4 homozygotes aged 60–75 | Stopped 2019 Umibecestat worsened cognition slightly; program ended. |
Status changes often; each trial name links to its ClinicalTrials.gov record. To volunteer, search ClinicalTrials.gov or use the Alzheimer’s Association’s TrialMatch.