119P HER2+ early-stage breast cancer treated with extended adjuvant neratinib in the context of the European Early Access Program: NEAR study final results

Neratinib is approved based on the phase III ExteNET study in Europe since 2018 to treat adult patients with Hormone Receptor-positive/Human Epidermal Growth Factor Receptor 2-positive (HR+/HER2+) early-stage breast cancer (eBC) completing adjuvant trastuzumab-based therapy <1 year ago (EU label). A 2017 Early Access Program (EAP) granted neratinib access to patients awaiting product availability. The eBC treatment landscape has evolved since ExteNET, and there is a need to assess neratinib safety and effectiveness in the recent treatment landscape. NEAR is a retrospective, observational study in Belgium, Croatia, France, Italy, and Spain in adults with HER2+ eBC receiving ≥1 dose of neratinib in the context of the EAP between Aug 1, 2017, and Dec 31, 2020. Patient characteristics were presented in 2023.1 Here we present data on neratinib treatment patterns, safety, and 2-year effectiveness. As of Jan 31, 2023, 108 patients were included in the full analysis set (FAS), of which 92 were HR+ and 74 met the EU label criteria; median follow up was 28 months. Key patient characteristics are summarised in the table. Initial neratinib dose was 240 mg in 87% of both the FAS and the EU label subgroup; the rest received <240 mg. The most common adverse event (AE) was diarrhoea (all grades/grades 3–4: 58%/8% in the FAS; 53%/8% in the EU label subgroup), followed by other gastrointestinal AEs. Prophylactic antidiarrhoeal treatment was given in 44% of the FAS and in 47% of the EU label subgroup. At 2 years, in the HR+ and EU label subgroups, invasive/distant disease-free survival were 93%/94% and 95%/96%, respectively; overall survival was 98% and 97%. No central nervous system metastases were observed.Table: 119PKey patient characteristics1, pre-treatments received1, and neratinib therapy patternsFAS (N=108)EU label subgroup (n=74)Median age min, max, years48 30, 7249 30, 72Pre-menopausal, %3741Stage I, %Stage II + III, %Missing, %17749157411High recurrence risk profile‡, %8181Prior neoadjuvant therapy, %5865Prior anti-HER2 adjuvant therapy, %Of which on trastuzumab, %91889190Median months min, max from adjuvant therapy to neratinib initiation4.6 0.3, 243.2 0.3, 12Median min, max months on neratinib12.3 0.03, 1612.1 0.3, 16‡Stage II/III or N+ or no pathologic complete response Open table in a new tab ‡Stage II/III or N+ or no pathologic complete response This study provides additional data supporting the use and management of extended adjuvant neratinib in clinical practice.