Multicenter Randomised Trial Of Paclitaxel (P) Maintenance Chemotherapy (Ct) Versus Control In Metastatic Breast Cancer (Mbc) Patients Achieving A Response Or Stable Disease To First-Line Ct Including Anthracyclines And Paclitaxel: Final Results From The Italian Manta Study.

522 Background: To evaluate the role of maintenance treatment with P after Ist line CT with an antracycline-paclitaxel containing regimen in MBC, in terms of Progression free Survival (PFS). Methods: MBC pts received induction CT with one of the following regimens (induction phase): A) Epirubicin (E) 90 mg/sqm + Paclitaxel (P) 200 mg/sqm (3 hrs), Q 3 weeks; B) Doxorubicin (D) 50 mg/sqm 16 hrs before P 200 mg/sqm (3 hrs) Q 3 weeks; C) D 50 mg/sqm day 1 + P 200 mg/sqm day 2 (3 hrs) Q 3 weeks for a maximum of 8 courses. Pts who achieved a response or SD were randomised to receive P 175 mg/m2 Q 3 weeks for 8 additional courses or control (no CT). The initial hypothesis was that maintenance CT could induce a 3 month absolute improvement of PFS in responding (or SD) patients. Planned sample size was 400 patients, to be enrolled in 2 yr period with an additional 2 yr period follow up. Results: from April 1998 to August 2003, 451 MBC pts have entered the induction phase, of these 253 have been randomised, by 22 italian centers. Due to the low accrual rate, in June 2003 an unplanned ad interim analysis was performed according to the Baeysian method for data monitoring of clinical trials accruing pts over several years. The aim of this analysis was to evaluate if the MANTA trial could be terminated because early results suggesting there is unlikely to be any treatment difference. A prior distribution was chosen to provide an estimate of initial beliefs concerning the size of the potential terapeutic effect. This analysis showed that there is only a small chance (11.7%) that there could be a 3 or more month difference between the 2 arms, adopting the stance of an enthusiast. Conclusions: After these data the trial was discontinued and the final analysis is ongoing. Final results from the MANTA trial will be presented at the meeting. No significant financial relationships to disclose.