5505 Background: The majority of advanced ovarian cancer patients (pts) in CR after debulking surgery and Platinum/Paclitaxel will eventually relapse. Role of maintenance CT is still questionable even if a SWOG/GOG trial has shown an improved progression free survival (PFS) with 12 vs 3 cycles of maintenance Pac. In March 1999, the After 6 Italian Cooperative Group initiated a phase III study to determine if maintenance Pac could prolong PFS in pts with a clinical (cCR) or pathological CR (pCR) after first line CT Methods: Pts with advanced ovarian cancer in cCR or pCR after 6 cycles of Platinum/Paclitaxel, were randomised to observation or 6 cycles of Pac 175 mg/sqm iv q 3 wks. Primary end point: PFS; secondary end points: overall survival (OS) and toxicities. Planned sample size: 250 pts to detect a 15% absolute increase in 2-yr PFS. Results: From 03/99 to 07/06, 200 pts were randomised. Due to the low accrual rate, an unplanned interim analysis of futility according to the Bayesian approach was perform...