Matters PERTAINing to triple positivity.
The Study: The international phase 2 PERTAIN trial enrolled 258 post-menopausal women with upfront metastatic or recurrent HR(+), HER2(+) breast cancer. Some had received previous adjuvant chemo but none for metastatic or recurrent disease. They were randomized to aromatase inhibition (with anastrozole or letrozole) + trastuzumab +/- pertuzumab. Importantly, after enrollment but before starting endocrine / HER2 therapy, over half of patients first received a taxane q3 weeks x 6-8 cycles per physician preference. The primary endpoint of progression free survival (PFS) was significantly improved with versus without dual HER2 therapy: 19 versus 16 months, repsectively. This benefit was more pronounced among those not receiving induction chemo with median PFS times of 22 and 12 months, respectively. Of note, heart toxicity was minimal with 87% of patients with and 90% without dual HER2-blockade maintaining a left ventricular ejection fraction ≥ 45%.
Bottom Line: The latest data continues to support chemo-free triple therapy for triple positive breast cancer with endocrine therapy and dual HER2-blockade. | Rimawi, J Clin Oncol 2018