Novel strategy to identify drugs that delay relapse.

3075 Background: There is an urgent need for methods to screen novel agents capable of stabilizing advanced cancer, prior to undertaking large randomized trials. This study was set up to determine whether, in asymptomatic relapsed ovarian cancer patients, their rising CA125 levels could be used to test the activity of such novel drugs. For proof of principle, tamoxifen is used. Methods: Patients with ovarian cancer who had responded to relapse chemotherapy were registered and had regular CA125 measurements: tamoxifen was started when CA125 reached × 4 nadir or × 4 ULN. Slopes of the regression of lne (CA125) against time for the last three values before starting tamoxifen and the first three levels after starting tamoxifen were compared for each patient. A repeated measures t-test was conducted to determine the magnitude and statistical significance of the difference between the mean slope before starting tamoxifen and during tamoxifen treatment. Results: To date 73 of 172 (42%) of subjects had 3 CA125 le...