Phase II, open-label trial of lapatinib and vinorelbine in women with previously treated HER2-positive metastatic breast cancer

Aim: To evaluate the efficacy and tolerability of lapatinib (L) and intravenous vinorelbine (V) in patients with metastatic HER2-positive breast cancer who have previously received two lines of anti-HER2 therapy (i.e. trastuzumab [T] with chemotherapy and lapatinib with capecitabine [LC]). Method: Consenting patients with measurable or evaluable disease and normal cardiac function who had progressed were recruited. Patients received LV (lapatinib 1250mg orally daily, vinorelbine 20mg/m² intravenously on days 1 and 8 every 3 weeks) until progressive disease, intolerable toxicity or patient request. Results: The trial was closed early following inclusion of 19 patients due to slow accrual. Ten, five and four patients had received two, three andmore thanfour lines of chemotherapy with T and LC, respectively, prior to study entry. Patients received a median of 5 cycles (range 1-18) of LV. Confirmed partial response was seen in 2 of 16 patients with measurable disease (12.5%); stable disease>24 weeks was seen in two patients (10.5%) with a clinical benefit rate of 20%. Fatigue and any grade neutropenia occurred commonly, but grade 4 severity occurred in only 5 and 11%, respectively. There were no episodes of cardiac dysfunction and no treatment-related deaths. The median progression-free survival was 3.9 months and overall survival (OS) was 9.1 months. Conclusion: The combination of LV demonstrated modest efficacy but was well tolerated. This combination may be of benefit to those patients who are unable to access the newer anti-HER2 agents and the low rate of treatment-emergent adverse effects will enable patients' symptoms, such as pain, to be minimized.