The docetaxel (T), carboplatin (C) and trastuzumab (H) regimen has been used in the (neo-) adjuvant treatment of HER2+ early stage breast cancer (ESBC). Lapatinib (L) a small molecule HER2 antagonist produces clinical responses following H failure.

We randomly assigned 88 patients with stages Ic–III HER2+ESBC to receive neoadjuvant TCH, TCL or TCHL followed by surgery and 1 year of H. The primary endpoint was pathological complete response (pCR). Secondary objectives were overall and disease-free survival (OS, DFS).

The TCL arm was closed following demonstration of inferiority of L in another trial. The pCR rates for TCH and TCHL were 52.8 and 51.6 (p = 1.0). At a median 4.8 years follow-up, TCHL patients had a significantly superior DFS; however, OS was similar. Prophylactic loperamide reduced the frequency of diarrhoea. Serum biomarker analysis identified a link between high tumour T-cell levels and high red blood cell, haematocrit, and haemoglobin following commencement of therapy.