Adjuvant regimens with trastuzumab administered for small HER2-positive breast cancer in routine clinical practice

Purpose: Trastuzumab has proven to improve the prognosis of HER2-positive breast cancer, but the information available about its administration for small tumors is still limited. Therefore, we assessed the use of adjuvant regimens with trastuzumab for the treatment of small HER2-positive breast cancer in routine clinical practice. Methods: This observational study was conducted in patients with HER2-positive breast adenocarcinoma =1.5 cm who received trastuzumab-based adjuvant treatment in clinical practice. Clinical/histopathological data were retrieved from patients’ medical charts. Results: A total of 101 evaluable patients were enrolled (median age range], 56.7 49.0–64.8] years//ECOG 0, 98.0 %//ductal carcinoma, 88.1 %//lymph nodes N0, 79.2 %). Only five (5.0 %) patients received neoadjuvant treatment, while all patients underwent tumor surgery. Adjuvant trastuzumab was administered at a mean (±SD) dose of 5.9 ± 1.5 mg/kg/cycle, and mostly in a three-weekly schedule (89 89.0 %] patients). The most frequent adjuvant therapy used with trastuzumab was chemotherapy (87 86.1 %] patients), followed by radiotherapy (63 62.4 %] patients) and hormone therapy (52 51.5 %] patients). Chemotherapy regimens mainly included doxorubicin, cyclophosphamide and paclitaxel/docetaxel (n = 30), docetaxel and cyclophosphamide (n = 15), docetaxel and carboplatin (n = 13). Hormone therapy mainly included letrozole (n = 17) and tamoxifen (n = 17). Nine (8.9 %) patients reported trastuzumab-related adverse events//only one allergic reaction reached grade 3 toxicity. Conclusion: This study shows that trastuzumab-based adjuvant treatment of small HER2-positive breast cancer is mostly based on chemotherapy—mainly paclitaxel/docetaxel. Adjuvant administration of trastuzumab for small HER2-positive breast cancer seems to be similar to that used for larger tumors

NSABP FB-7: A phase II randomized neoadjuvant trial with paclitaxel + trastuzumab and/or neratinib followed by chemotherapy and postoperative trastuzumab in HER2+ breast cancer

PURPOSE: The primary aim of NSABP FB-7 was to determine the pathologic complete response (pCR) rate in locally advanced HER2-positive (HER2(+)) breast cancer patients treated with neoadjuvant trastuzumab or neratinib or the combination and weekly paclitaxel followed by standard doxorubicin plus cyclophosphamide. The secondary aims include biomarker analyses. EXPERIMENTAL DESIGN: pCR was tested for association with treatment, gene expression, and a single nucleotide polymorphism (SNP) in the Fc fragment of the IgG receptor IIIa-158V/F (FCGR3A). Pre-treatment biopsies and residual tumors were also compared to identify molecular changes. RESULTS: The numerical pCR rate in the trastuzumab plus neratinib arm (50% [95%CI 34-66%]) was greater than that for single-targeted therapies with trastuzumab (38% [95%CI 24-54]) or neratinib (33% [95%CI 20-50]) in the overall cohort but was not statistically significant. Hormone receptor-negative (HR(-)) tumors had a higher pCR rate than HR(+) tumors in all three treatment arms, with the highest pCR rate in the combination arm. Diarrhea was the most frequent adverse event and occurred in virtually all patients who received neratinib-based therapy. Grade 3 diarrhea was reported in 31% of patients; there were no grade 4 events. Our 8-gene signature, previously validated for trastuzumab benefit in two different clinical trials in the adjuvant setting, was correlated with pCR across all arms of NSABP FB-7. Specifically, patients predicted to receive no trastuzumab benefit had a significantly lower pCR rate than did patients predicted to receive the most benefit (P = 0.03). FCGR genotyping showed that patients who were homozygous for the Fc low-binding phenylalanine (F) allele for FCGR3A-158V/F were less likely to achieve pCR. CONCLUSIONS: Combining trastuzumab plus neratinib with paclitaxel increased the absolute pCR rate in the overall cohort and in HR(-) patients. The 8-gene signature, which is validated for predicting trastuzumab benefit in the adjuvant setting, was associated with pCR in the neoadjuvant setting, but remains to be validated as a predictive marker in a larger neoadjuvant clinical trial. HR status, and the FCGR3A-158V/F genotype, also warrant further investigation to identify HER2(+) patients who may benefit from additional anti-HER2 therapies beyond trastuzumab. All of these markers will require further validation in the neoadjuvant setting. TRIALS REGISTRATION: ClinicalTrials.gov, NCT01008150. Retrospectively registered on October 5, 2010