Original ResearchEfficacy 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

•3-year event-free survival data in PrefHer were consistent with previous trials.•The overall safety profile during adjuvant treatment was as expected.•H SC was well tolerated and no new safety signals were identified.

AimTo assess efficacy (event-free survival, EFS) and safety in patients followed up for 3 years in the PrefHer study (NCT01401166).Patients and methodsPost surgery and post chemotherapy in the (neo)adjuvant setting, patients with human epidermal growth factor receptor 2 (HER2)-positive early breast cancer were randomised to receive four cycles of the subcutaneous form of trastuzumab (Herceptin® SC [H SC] via single-use injection device [Cohort 1] or delivery via a hand-held syringe from an SC Vial [Cohort 2]; 600 mg fixed dose) followed by four of the intravenous form of trastuzumab (Herceptin® [H IV]; 8 mg/kg loading, 6 mg/kg maintenance doses) in the adjuvant setting or vice versa every 3 weeks. Patients could have received H before randomisation. H was then continued to complete a total of 18 cycles, including any cycles received before randomisation.ResultsA total of 488 patients were randomised across both cohorts. After median follow-up of 36.1 months, 3-year EFS across both groups in the evaluable intention-to-treat population (467 patients) was 90.6% overall, 89.9% in Cohort 1, and 91.1% in Cohort 2. No new safety signals were identified during long-term follow-up, with only one cardiac serious adverse event in the safety population (483 patients).ConclusionsThree-year EFS data following H SC and H IV treatment are consistent with those reported by previous trials for H in the adjuvant setting. The overall safety profile during adjuvant treatment was as expected.