Adjuvant Therapy for HER2-Positive Early Breast Cancer

Key Findings and Recommendations

• The National Comprehensive Cancer Network (NCCN) recommends up to 1 year of HER2-targeted therapy with trastuzumab, and based on updated APHINITY data, the addition of pertuzumab may be considered with trastuzumab in those with node-positive disease 1, 2
• Adding pertuzumab to standard trastuzumab-based adjuvant therapy provides meaningful clinical benefit, particularly in higher-risk populations, with a 24% relative reduction in recurrence risk (HR 0.76; 95% CI 0.64-0.91) 3
• In patients with node-positive disease, the absolute benefit was 4.5% at 6 years, with invasive disease-free survival (IDFS) of 87.9% versus 83.4% (HR 0.72; 95% CI 0.59-0.87) 3
• The NCCN panel recommends trastuzumab plus pertuzumab as a Category 1 recommendation for completing up to 1 year of HER2-directed therapy in patients who were node-positive at initial staging and received neoadjuvant therapy 4
• The 6-year IDFS improved from 87.8% with trastuzumab alone to 90.6% with dual HER2 blockade 3
• With longer follow-up, pertuzumab's benefit became apparent in HR-positive disease: 6-year IDFS HR 0.73 (95% CI 0.59-0.92) 3
• Patients with HR-positive disease should receive adjuvant endocrine therapy (Category 1) in addition to HER2-directed therapy 4
• LVEF should be evaluated prior to initiation and every 3 months during therapy per FDA recommendations 1, 2
• Anthracycline and taxane-based regimens with HER2-targeted agents carry increased cardiac toxicity risk 1, 2
• The survival benefit (overall survival) has not yet reached statistical significance (HR 0.85; 95% CI 0.67-1.07, P=0.170), though fewer deaths occurred in the pertuzumab arm (5.2% vs 6.1%) 3