APHINITY analysed whether adjuvant pertuzumab – which also acts on the HER2 marker – in combination with trastuzumab and chemotherapy in patients was better than standard treatment. The study’s first results, presented at American Society of Clinical Oncology Annual Meeting 2017 and published in the New England Journal of Medicine that same year, found that this new dual anti-HER2 therapy regimen reduced the risk of breast cancer recurrence or death by 19% compared to trastuzumab and chemotherapy alone. At three years, 94,1% of patients treated with pertuzumab in combination with trastuzumab and chemotherapy did not see a breast cancer recurrence, compared to 93,2% of patients treated with trastuzumab and chemotherapy alone.
The first results of the APHINITY trial therefore showed a modest benefit from adding pertuzumab to trastuzumab, in itself an important step in advancing cancer care for patients – especially for women with the highest risk – those with node-positive and hormone-receptor negative breast cancer.
The updated results, presented at the San Antonio Breast Cancer Symposium 2019 and published in the Journal of Clinical Oncology in 2021, showed that, after six years of follow-up, the greatest benefit remained in patients at high risk of recurrence, such as those with lymph node-positive disease, but regardless of hormone receptor status. Although fewer deaths were seen among the patients who received treatment with pertuzumab, the data are still immature and have not shown definitive improvement in overall survival, which will be reviewed again at a next interim analysis. Over the course of the clinical trial, samples were collected from all participating patients for future research. These samples will help identify biomarkers, which can help to predict response or toxicity of the dual anti-HER treatment, and better understand the biology of HER2+ tumours as well as develop and validate diagnostic tests.