Weekly cisplatin-epirubicin-paclitaxel with G-CSF support (PET) vs. triweekly epirubicin-paclitaxel (ET) in metastatic breast cancer (MBC). Final results of the 9908 SICOG trial

Abstract

580 Background: The present study was aimed at comparing the antitumor activity of 12 weekly PET cycles with that of 6 triweekly ET cycles in MBC patients. Methods: Women with MBC, aging < 70 years, with ECOG P.S. 0–2 were randomized to receive 12 weekly cycles of cisplatin 30 mg/m2, epirubicin 50 mg/m2, paclitaxel 120 mg/m2 with G-CSF d 3–5 each week, or 6 cycles of epirubicin 90 mg/m2, paclitaxel 175 mg/m2 every 3 weeks. Time to Treatment Failure was the main end-point. One-hundred and twenty pts. per arm were planned. An interim analysis focusing on TTF was planned on the first 60 pts./arm enrolled, according to the Schaid’s design. A minimum follow-up of 6 months from the last pt. enrolled was required. Early stopping rules: p > 0.32 or p< 0.01. Results: The planned interim analysis was performed on May the 1st 2004, when 60 pts. in each arm had a minimum potential follow-up of 6 months. Overall 145 patients had been recruited at that time (PET=72; ET=73). Overall 96 failures had occurred among the 120 analysed pts. (PET=51 ET=45). Median TTF being 11.7 and 12.3 months in PET and ET respectively (p=0.66). 55 deaths had occurred (PET=24 ET=31), MST being 46 and 36 months for PET and ET arm respectively (p=0.37). Responses were as follows: PET: 11 CRs, 34 PRs for an ORR of 75%; ET: 8 CRs, 20 PRs, for an ORR of 47% (p=0.001) Anaemia, mucositis, peripheral neuropathy, and gastrointestinal toxicity were substantially more frequent in the PET arm. On October 15° a further analysis including all 145 enrolled pts. has been performed. Median TTFs were 11.7 and 12.6 months for PET and ET, respectively. Conclusions: PET weekly regimen is superior to standard ET in terms of ORR in MBC patients. However, Time to Treatment Failure, which was the main end-point of the present study, was superimposible in the two arms. In view of that, the accrual has been stopped and the null hypothesis accepted. No significant financial relationships to disclose.