A phase II trial of oxaliplatin and trastuzumab in the treatment of HER2-positive metastatic breast cancer.

We investigated the feasibility/efficacy of oxaliplatin in combination with trastuzumab as first-/second-line treatment of HER2-positive metastatic breast cancer (MBC). Patients received oxaliplatin/trastuzumab every 21 days and were evaluated every 6 weeks using RECIST criteria. The study closed early due to slow accrual. Twenty-five patients were evaluable; of these, 5 (20%) had objective responses to oxaliplatin/trastuzumab. Therapy was well tolerated (no grade-4 and gastrointestinal grade-3 toxicity in 4% of patients), but had only modest activity (median time-to-progression 1.8 months). Substitution of oxaliplatin for cisplatin or carboplatin, in combination with trastuzumab, does not appear to improve first-/second-line therapy in HER2-positive MBC.