- 6 months of adjuvant trastuzumab was not noninferior to 12 months for preventing recurrence of human epidermal growth factor receptor 2 (HER2)-positive early breast cancer in the final analysis of the PHARE trial.
Why this matters
- Multicenter, open-label, phase 3 randomized controlled trial (n=3384) comparing 6 vs 12 months adjuvant trastuzumab.
- All had nonmetastatic, operable, with either positive axillary nodes or negative axillary nodes but a tumor of ≥10 mm.
- Primary outcome: DFS with a prespecified hazard margin of 1.15.
- Funding: French National Cancer Institute.
- Median follow-up was 7.5 (interquartile range [IQR], 5.3-8.8) years.
- The 6-month group had 21.2% events relevant to DFS, whereas the 12-month group had 20.4%.
- The aHR for DFS in the 12- vs 6-month group was 1.08 (95% CI, 0.93-1.25; P=.39). Because the prespecified noninferiority margin of 1.15 was included in the 95% CI, results were inconclusive regarding the noninferiority hypothesis.
- No change in adverse events compared with earlier PHARE, including cardiac safety.
- Open-label design.