P01
Discriminant Analysis (PROC DISCRIM) To Separate A Study Population By Treatment Subgroups In A Clinical Trial With A New Antidepressant
Lev Sverdlov, Innapharma, Inc

Data were evaluated from a pilot phase 2 clinical trial (N=55) with a new antidepressant and multivariate discriminant analysis (PROC DISCRIM) was used to separate the drug-treated from placebo populations by treatment subgroups. The list of variables for discriminant analysis included the percent of change from baseline for the primary efficacy variable (21-item Hamilton Depression Rating Scale – HAMD-21) for 11 major time points from Day 3 (the first day of evaluation after treatment) to Day 40 (the las t day of evaluation at the end of the trial). Separation with discriminant analysis was very effective for any combination of two of three treatment subgroups (from 82.4% to 86.7% of subjects with the correct classification by treatment subgroups) and for the three treatment subgroups together (80% of subjects with correct classification).