Adult women with metastatic TNBC with a maximum of 1 previous chemotherapy regimen were eligible. Patients received gemcitabine intravenous (I.V.) 1500 mg/m2, carboplatin area under the concentration-time curve = 2.5 I.V., and panitumumab 6 mg/kg I.V. every 2 weeks. Treatment continued until disease progression or unacceptable toxicity, with disease evaluations every 6 weeks. The primary end point was progression-free survival (PFS). Archival tissue was collected for correlative analysis, to include phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha, p53, phosphatase and tensin homolog, EGFR, and status.
Between May 2010 and August 2012, 71 women (median age, 54 years; 14% de novo stage IV) were treated. At a median follow-up of 11 months, the median PFS was 4.4 months (95% confidence interval, 3.2-5.5 months). The objective response rate was 42% (complete response, 1; partial response, 29). Treatment-related toxicity included: rash, 50 patients (70%), fatigue, 37 patients (52%), neutropenia, 32 patients (45%; 2 episodes of febrile neutropenia), and thrombocytopenia, 32 patients (45%).
Although the addition of panitumumab was feasible, the results of this trial do not support combination of panitumumab with gemcitabine and carboplatin in the treatment of patients with TNBC.