Weekly Cisplatin-Epirubicin-Paclitaxel (Pet) With Granulocyte-Colony Stimulating Factor Support Versus Tri-Weekly Epirubicin-Paclitaxel In Locally Advanced Breast Cancer: Final Comprehensive And Subgroup Analysis Of A Sicog Phase Iii Study.

572 Background: We previously reported the preliminary pathological response data of a phase III trial comparing a weekly dose-dense approach (PET) to a standard epirubicin-paclitaxel q3wk combination, in LABC pts. (ASCO 2004; abstr.511). In the present abstract, we report the final data on response and PFS, and a subgroup analysis according to the hormone-receptor, and HER2/neu status. Methods: Overall, 200 patients with stage IIIB disease were randomised to receive either 12 weekly cycles of cisplatin 30 mg/m 2 , epirubicin 50 mg/m 2 , and paclitaxel 120 mg/m 2 (PET) plus granulocyte-colony stimulating factor support, or 4 cycles of epirubicin 90 mg/m 2 + paclitaxel 175 mg/m 2 (ET) every 3 weeks. Results: Overall, a pCR in both breast and axilla occurred in 16 (16%) PET patients and in 6 (6%) ET patients (P=0.02). The higher activity of PET was evident only in ER negative (27.5% vs 5.4%; P=0.026), and in HER/neu 3+ (31% vs 5%; P=0.037) tumours. The 2 arms yielded similar pCR rate in ER positive (PET/ET=7.5%/7.1%) and HER/neu negative (PET/ET=10%/6%) patients. At a 45 months median follow-up, 78 patients showed a progression or relapse (PET= 32 vs ET= 46). The 5-year Failure-free survival rates in PET/ET arms were: Total =27%/21%; ER+= 26%/23%; ER- =25%/9%; HER2+=.18%/11%; HER2- =29%/25%. Conclusions: The PET weekly regimen is superior to ET in terms of pCR rate in LABC patients. The advantage of such an aggressive approach is limited to ER negative and HER2 positive pts. A large randomised trial comparing weekly PET to a standard regimen in ER- LABC pts., with FFS as the main end-point, is highly recommendable. No significant financial relationships to disclose.