Table 1 Summary of key trial design features, trial planning, and actual site recruitment outcomes
From: Recruitment across two decades of NIH-funded Alzheimer’s disease clinical trials
Intervention | Donepezil/vitamin E | NSAIDs | Simvastatin | Vitamin B | Valproate | Huperzine A | DHA | IVIG | Resveratrol | INI | FYN |
|---|---|---|---|---|---|---|---|---|---|---|---|
Initiation year | 1999 | 1999 | 2002 | 2003 | 2003 | 2004 | 2007 | 2008 | 2012 | 2014 | 2014 |
Trial phase | 3 | 2/3 | 3 | 3 | 3 | 2 | 3 | 3 | 2 | 2/3 | 2 |
Diagnostic category | MCI | Mild to moderate AD | Mild to moderate AD | Mild to moderate AD | Moderate AD | Mild to moderate AD | Mild to moderate AD | Mild to moderate AD | Mild to moderate AD | MCI and Mild AD | Mild AD |
Trial length (months) | 36 | 12 | 18 | 18 | 24 | 4 | 18 | 18 | 12 | 12 | 12 |
Planned total sample size, n | 720 | 320 | 400 | 400 | 300 | 210 | 400 | 385 | 120 | 240 | 152 |
Number of sites, n | 70 | 40 | 45 | 39 | 43 | 32 | 51 | 45 | 25 | 27 | 22 |
Expected site recruitment, participants/site | 10.3 | 8.0 | 8.9 | 10.3 | 7.0 | 6.6 | 7.8 | 8.6 | 4.8 | 8.9 | 6.9 |
Actual site recruitment, participants/site (mean, SD [range]) | 11.3 ± 6.1 [0–35] | 8.8 ± 3.7 [3–15] | 9.0 ± 4.9 [0–23] | 10.5 ± 8.4 [1–44] | 7.3 ± 6.2 [0–32] | 6.6 ± 4.8 [0–18] | 7.9 ± 4.9 [0–23] | 8.7 ± 5.5 [0–21] | 4.8 ± 4.4 [0–18] | 10.7± 7.9 [0–32] | 7.2 ± 6.3 [1–32] |
Overall recruitment rate, screened participants/site/month | 1.47 | 1.19 | 0.41 | 0.57 | 0.31 | 0.25 | 1.21 | 0.54 | 0.65 | 0.40 | 0.73 |
Overall recruitment rate, randomized participants/site/month | 0.51 | 0.88 | 0.24 | 0.39 | 0.19 | 0.18 | 0.88 | 0.30 | 0.43 | 0.40 | 0.33 |