Final results of After-6 protocol 1: A phase III trial of observation versus 6 courses of paclitaxel (Pac) in advanced ovarian cancer patients in complete response (CR) after platinum-paclitaxel chemotherapy (CT)

Abstract

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 performed. Main patient characteristics: median age 58 yrs, median PS 0 (neurotoxicity ≥ G 2 was an exclusion criteria), stage IIb/IIc 15%, stage III 79%, stage IV 6%; 105 pts (52.5%) were in pCR. 14% of pts randomised to observation received Pac; 22% of pts randomised to Pac stopped treatment after 2–5 cycles (progression or death: 3 pts; toxicity: 9 pts; refusal: 7 pts; others: 3 pts). A G ≥ 2 neurotoxicity was reported in 25% of pts treated with Pac; other toxicities were mild. After a median follow up of 44 months, 94 pts (47%) have relapsed and 42 pts (21%) died. Median PFS were 34 and 34.5 months in observation and Pac arm respectively; 3-yr OS was 88% in observation and 78% in Pac arm. Irrespectively of treatment arm, median PFS was 34.4 months for pts with pCR and 24.5 months for those with cCR; 3-yr survival rates were 87% and 79% respectively (p=0.04). Conclusions: Six courses of maintenance Pac do not prolong PFS or OS in pts in CR after first line platinum/paclitaxel. Irrespectively of assigned treatment, the outcome of these pts is more favourable than previously reported and significantly better in the pCRs. Maintenance CT remains an experimental treatment that should be tested in pts at high risk of relapse. [Table: see text]