Long term HER2+ metastatic breast cancer survivors treated by trastuzumab: Results from the French cohort study LHORA.

PURPOSE: The LORHA study described the clinical features of patients and tumours in long-term responders from a subset of breast cancer patients who responded to 1st-line trastuzumab and without disease progression. METHODS: This was an ambispective, multicentre, non-interventional study conducted in 57 centres in France. Eligible patients were women with HER2+metastatic or locally-advanced breast cancer, treated with 1st-line therapy, progression-free for ≥3 years after starting trastuzumab, and followed-up for 12 months. RESULTS: 160 patients were recruited, 128 were included in the efficacy analysis subset (median age: 61 years; [34-95 years]). A majority (88%) had invasive ductal carcinoma; 53% had SBR grade III carcinoma, and 58% were positive for hormonal receptors. The median time since diagnosis was 8 years [3-26 years]. The most frequent metastatic sites were the bone, liver, lymph nodes, and lungs in 43%, 35%, 20% and 19% of patients, respectively. The median duration of 1st-line trastuzumab was 4.5 years [0.8-12.1], combined with paclitaxel and docetaxel in 35 and 72 patients, respectively. Median PFS (progression-free survival) was 6.4 years [5.7; Not Reached]. No trastuzumab-related deaths were observed. In the safety analysis subset (N = 134), 3 cardiac adverse events considered related to trastuzumab were recorded in 3 patients (2.2%), and only one prospective congestive cardiac failure was of grade ≥3. CONCLUSIONS: The LORHA study showed that long term responders to 1st-line trastuzumab for locally advanced or metastatic breast cancer could achieve a median PFS of more than 6 years, with an acceptable safety profile.