Bcirg 007: Randomized Phase Iii Trial Of Trastuzumab Plus Docetaxel With Or Without Carboplatin First Line In Her2 Positive Metastatic Breast Cancer (Mbc): Main Time To Progression (Ttp) Analysis.

LBA516 Background: Based on preclinical synergism between docetaxel (T), carboplatin (C) and trastuzumab (H), BCIRG conducted a phase III trial for women with HER2+ MBC to evaluate efficacy and safety of H in combination with T or TC. Methods: 263 patients (pts) with HER2 FISH+ MBC were randomized to TH, (H with T 100 mg/m2) or TCH, (H with T 75 mg/m2 and C AUC=6). Chemo was given q3 wks for 8 cycles with wkly H at 2 mg/kg (loading dose of 4 mg/kg), followed by H q3 wks at 6 mg/kg until progression. Pts were stratified by centre and prior (neo) adjuvant taxane chemotherapy. Primary endpoint was TTP with 80% power (0.05 significance) to detect a 50% improvement in median TTP between the 2 arms. Secondary endpoints include overall survival, response rate, duration of response (DR), clinical benefit (CB) and safety. Results: 131 pts were treated in each arm. Pt characteristics were well balanced in both groups. Importantly, only 52% of pts received C at the protocol specified dose (RDI > 0.9). Efficacy analysis was conducted at 204 events. There was no significant difference between TH and TCH in median TTP (11.1 vs 10.4 mos, p = 0.57), ORR (73% in both arms), DR (10.7 vs 9.4 mos) and CB (67% in both arms). The most common gr 3/4 toxicities were: infection (44% vs 30%), neutropenic infection (22% vs 12%), thrombocytopenia (2% vs 15%), febrile neutropenia (12% vs 13%) asthenia (5% vs 12%), anemia (5% vs 11%), and diarrhea (2% vs 9%). Two pts died (1.5%) due to sepsis in TCH. Absolute LVEF decline > 15% were seen in 5.5% vs 6.7% of pts. One pt (0.8%) had a symptomatic CHF in TH arm Conclusions: The already effective TH regimen does not benefit from the addition of C, when the T dose in TH is 100 mg/m2 and 75 mg/m2 in TCH, in women with HER2+ MBC. No significant financial relationships to disclose.