209P - Efficacy and safety of subcutaneous trastuzumab and intravenous trastuzumab as part of adjuvant therapy for HER2-positive early breast cancer: final analysis of the randomised, two-cohort PrefHer study

Abstract

PrefHer (NCT01401166) revealed a compelling and consistent patient preference for adjuvant subcutaneous trastuzumab (Herceptin® SC; H SC) over intravenous H (H IV) in HER2-positive early breast cancer, regardless of single-use injection device (Cohort 1) or hand-held syringe (Cohort 2) delivery. We report 3-year event-free survival (EFS) and safety. Post-surgery and (neo)adjuvant chemotherapy, patients were randomised to receive four adjuvant cycles of H SC (600 mg fixed dose) followed by four of H IV (8 mg/kg loading, 6 mg/kg maintenance doses), or vice versa every 3 weeks. Following this crossover period, patients continued H SC or H IV therapy to complete 18 standard cycles. H IV was allowed prior to randomisation. EFS was assessed using the Kaplan–Meier approach and is shown for the overall evaluable intention-to-treat population (patients who completed the primary preference question and ≥1 administration of both H SC and H IV) in both cohorts combined. Adverse events (AEs) and serious AEs (SAEs) were reported according to NCI-CTCAE v4 and ICH E2A; data shown are combined from both cohorts (overall safety population) and include the crossover, H continuation and follow-up periods. Across 12 countries and 74 sites, 488 patients were randomised and 483 assessed for safety. The evaluable intention-to-treat population comprised 467 patients. Median follow-up was 36.1 months (range 0–45.9). The 3-year EFS rate in the overall evaluable intention-to-treat population was 90.6% (95% confidence interval 87.4–92.9). The AE profile is shown in the table.Tabled 1Patients, n (%)*Overall safety population N = 483AEs388 (80)Grade1360 (75)2214 (44)345 (9)4050SAEs19 (4)Related to study drugs1 (<1)Resolved without sequelae18 (4)*Could be counted once per grade but ≥once overall Open table in a new tab *Could be counted once per grade but ≥once overall EFS results confirm previous efficacy findings of H in the adjuvant setting. H SC was well tolerated and no new safety signals were identified compared with the known profiles of H IV or H SC from previous reports in HER2-positive early breast cancer.