ASCO—In the first overall survival analysis of the BCIRG 007 study in metastatic breast cancer, the addition of carboplatin(Drug information on carboplatin) to a docetaxel(Drug information on docetaxel) (Taxotere)/trastuzumab (Herceptin) regimen did not improve overall survival. Mark Pegram, MD, of the UCLA David Geffen School of Medicine, reported the results at the 2007 American Society of Clinical Oncology annual meeting (abstract LBA1008).

"There was no enhanced efficacy for the addition of carboplatin to trastuzumab(Drug information on trastuzumab) plus docetaxel. Both regimens were effective, but there were differences in toxicities," Dr. Pegram reported.

The 007 study of the Breast Cancer International Research Group (BCIRG) is a phase III trial in HER2-positive metastatic breast cancer patients previously untreated for metastatic disease. A total of 263 patients were randomized to receive one of the following regimens:

• Docetaxel, 100 mg/m² every 3 weeks for eight cycles, plus trastuzumab,
2 mg/kg loading, followed by 6 mg/kg every 3 weeks for 1 year (TH).

• Docetaxel 75 mg/m² plus carboplatin to AUC 6 every 3 weeks for eight cycles plus trastuzumab (TCH).

No significant differences were observed between TH and TCH with regard to median time to progression (11.1 vs 10.4 months, respectively) and overall response rate (73% in each arm). At a median follow-up of 39 months, median overall survival was 36.4 and 36.6 months, respectively, Dr. Pegram reported.

Toxicity Differences

Among grade 3-4 hematologic toxicities, febrile neutropenia rates were similar for TH and TCH. There was a trend toward more neutropenic infections with TH, but there were no septic deaths in the TH arm vs two in the TCH arm, "a cautionary note," he said. There was significantly more thrombocytopenia in the TCH arm (15% vs 2% for TH), but Dr. Pegram noted that none of the thrombocytopenia events were associated with bleeding symptoms or platelet transfusion.