Importance: Confirmation of long-term comparability between subcutaneous and intravenous trastuzumab is essential.
Objective: To evaluate efficacy and safety of subcutaneous trastuzumab compared with that of intravenous trastuzumab for patients with ERBB2 (HER2)-positive early breast cancer after 6 years' follow-up in the HannaH (Enhanced Treatment With Neoadjuvant Herceptin) trial.
Design, setting, and participants: Open-label, prospective, multicenter, international, neoadjuvant-adjuvant, randomized, phase 3 noninferiority clinical trial (primary end points: pathologic complete response and serum trough concentration predose cycle 8) conducted for 596 patients with ERBB2-positive early breast cancer enrolled from October 19, 2009, to December 1, 2010.
Interventions: Eligible patients received 8 cycles of chemotherapy (4 cycles of docetaxel, 75 mg/m2, followed by 4 cycles of fluorouracil, 500 mg/m2, epirubicin, 75 mg/m2, and cyclophosphamide, 500 mg/m2) with either fixed-dose subcutaneous trastuzumab, 600 mg, or intravenous trastuzumab (loading dose, 8 mg/kg; maintenance dose, 6 mg/kg) every 3 weeks in the neoadjuvant setting. Patients received an additional 10 cycles of subcutaneous trastuzumab or intravenous trastuzumab (according to their initial randomization) after surgery in the adjuvant setting to complete 1 year of anti-ERBB2 therapy.
Main outcomes and measures: Event-free and overall survival rates were calculated using the Kaplan-Meier method. Hazard ratios were estimated by Cox proportional hazards regression. Adverse events and serious adverse events were graded per standard criteria.
Results: In total, 294 women (mean [SD] age, 50.3 [11.1] years) treated with subcutaneous trastuzumab and 297 women (mean [SD] age, 49.5 [10.8] years) treated with intravenous trastuzumab were included in respective intention-to-treat populations. Six-year event-free survival rates (65% in both study groups; hazard ratio, 0.98; 95% CI, 0.74-1.29) and overall survival rates (84% in both study groups; hazard ratio, 0.94; 95% CI, 0.61-1.45) were similar between the subcutaneous and intravenous trastuzumab groups. Patients achieving a total pathologic complete response had longer event-free survival and higher 6-year overall survival rates than those with residual disease. Incidence of adverse events (290 of 297 [97.6%] vs 282 of 298 [94.6%]), grade 3 or higher adverse events (158 of 297 [53.2%] vs 160 of 298 [53.7%]), cardiac events (44 of 297 [14.8%] vs 42 of 298 [14.1%]), and serious adverse events (65 of 297 [21.9%] vs 45 of 298 [15.1%]) was comparable between the subcutaneous and intravenous trastuzumab treatment groups.
Conclusions and relevance: This final analysis of the HannaH trial further confirms the comparable efficacy and safety of subcutaneous and intravenous trastuzumab and highlights the suitability of subcutaneous trastuzumab as an alternative route of administration for patients with ERBB2-positive early breast cancer.
Trial registration: ClinicalTrials.gov identifier: NCT00950300.