ALLOP1

ALLOP1 is the LONI Image and Data Archive project for a phase 1b/2a clinical trial (NCT02221622) that tested the neurosteroid allopregnanolone as a regenerative treatment in early Alzheimer's disease. The trial ran at the University of Southern California from June 2015 to February 2018, and Lon Schneider and Roberta Diaz Brinton are the joint senior authors of its papers. Its primary aim was safety, tolerability and pharmacokinetics; brain MRI served as a safety check and as an exploratory outcome. Access to the archived data starts with a data use application on the IDA.

Composition

24 participants completed the trial: 18 received intravenous allopregnanolone once a week for 12 weeks in three dose cohorts, and 6 received placebo. All had mild cognitive impairment due to Alzheimer's disease or mild Alzheimer's disease, a Mini-Mental State Examination score of 20 to 26 and were at least 55 years old. The imaging paper reports 12 women and 12 men and a mean age of 75.9 years (range 60 to 89). Each participant was scanned twice, before treatment and at the end of the study. Paired T1-weighted data exist for 23 participants.

Acquisition

All scans come from one 3 T GE Signa HDxt scanner at USC, without contrast agent, using a protocol adapted from the ADNI 3T MRI protocol. The battery covers T1-weighted structural imaging, multi-shell diffusion imaging acquired as one sequence per shell, and resting-state functional MRI. The trial also read the scans for amyloid-related imaging abnormalities (ARIA-E and ARIA-H) and found none.

Known limitations

The cohort is very small and the placebo arm has six people, who were older on average than the treated group. The diffusion data have anisotropic voxels and fewer than 25 directions per shell. One participant lacks a T1-weighted scan, and two each have incomplete or poor-quality diffusion and resting-state data. The papers do not say which images were uploaded to the IDA, and the data use terms are not public.