Treatment of HER2-positive metastatic breast cancer with lapatinib and capecitabine in the lapatinib expanded access programme, including efficacy in brain metastases �C the UK experience

Background:

The global lapatinib expanded access programme provided access to lapatinib combined with capecitabine for women with HER2-positive metastatic breast cancer (MBC) who previously received anthracycline, taxane and trastuzumab.

Methods:

Progression-free survival (PFS) and safety data for 356 patients recruited from the United Kingdom are reported. Efficacy was assessed in 162 patients from the five lead centres, including objective tumour response rate (ORR), time to disease progression (TTP) and efficacy in those with central nervous system (CNS) metastases. Correlation of PFS and ORR with previous capecitabine treatment was also documented.

Results:

Overall, PFS for the 356 UK patients was 21 weeks (95% CI: 17.6–24.7). In the 162 assessable patients, ORR was 21% (95% CI: 15–27%) and median TTP was 22 weeks (95% CI: 17–27). Efficacy was greater in capecitabine-naive patients (ORR 23 vs 16.3%, P=0.008). For 34 patients with CNS metastases, ORR was 21% (95% CI: 9–39%), with evidence of improvement in neurological symptoms, and median TTP was 22 weeks (95% CI: 15–28).

Conclusions:

Lapatinib combined with capecitabine is an active treatment option for women with refractory HER2-positive MBC, including those with progressive CNS disease.     

Predictive value of HER2 serum levels in patients treated with lapatinib or trastuzumab - a translational project in the neoadjuvant GeparQuinto trial

Background:

We were able to demonstrate a predictive value of serum HER2 (sHER2) in patients receiving trastuzumab in the neoadjuvant GeparQuattro trial. However, the role of sHER2 in patients receiving neoadjuvant therapy (NT) with lapatinib is still unclear.

Methods:

The neoadjuvant GeparQuinto trial compared trastuzumab vs lapatinib in addition to chemotherapy in HER2-positive primary breast cancer patients. The sHER2 levels were measured by enzyme-linked immunosorbant assay in 210 patients, of whom 109 (52%) patients received trastuzumab and 101 (48%) lapatinib at three different time points.

Results:

Twenty-two percent of patients had elevated baseline sHER2 levels (>15 ng ml⁻¹). A decrease of sHER2 levels (>20%) in the trastuzumab and lapatinib-treated group during NT was seen in 44% and 24% of the patients, an increase of sHER2 levels (>20%) was seen in 6% and 41% of patients, respectively. Higher pre-chemotherapy sHER2 levels were associated with higher pathological complete remission (pCR) rates in the entire study cohort (OR 1.8, 95% CI 1.02–3.2, P=0.043). A decline of sHER2 levels (>20%) during NT was a predictor for pCR in the lapatinib-treated patient group (OR: 11.7, 95% CI 1.3–110, P=0.031).

Conclusion:

Results of this study demonstrate that sHER2 levels change differently during NT depending on the anti-HER2 treatment strategy. Elevated baseline sHER2 levels (>15 ng ml⁻¹) and a decrease of sHER2 levels (>20%) early after therapy initiation are both relevant criteria to predict response to lapatinib-based treatment.     

Impact of anti-HER2 therapy on overall survival in HER2-overexpressing breast cancer patients with brain metastases

Background:

Trastuzumab-based therapy after diagnosis of brain metastases (BM) may improve survival due to prolonged systemic disease control. We investigated whether lapatinib may yield additional survival benefit.

Methods:

Eighty patients with BM from HER2-positive breast cancer were identified. Karnofsky Performance Score (KPS) of at least 70 was required. We included a control group of 37 patients treated before 2003, when continuation of trastuzumab after diagnosis of BM was not yet recommended. Remainders received either trastuzumab or lapatinib and trastuzumab (either concomitantly or sequentially) with or without chemotherapy.

Results:

Median overall survival (OS) in patients receiving trastuzumab after diagnosis of BM was 13 months; corresponding numbers were 9 months in patients treated with chemotherapy, and 3 months with radiotherapy alone. Median OS was not reached in the lapatinib group. Addition of lapatinib prolonged OS over trastuzumab alone (P=0.002). After correction for potential confounders, lapatinib therapy remained an independent positive predictor for survival (HR 0.279; P=0.012).

Interpretation:

This retrospective single-centre study suggests that the introduction of lapatinib improved survival in patients with BM from HER2-positive breast cancer. Patients with KPS ⩾70 may benefit when treated with lapatinib in addition to trastuzumab after completion of local therapy.     

Effect of adjuvant trastuzumab among patients treated with anti-HER2-based neoadjuvant therapy

Purpose:

To study the impact of adjuvant trastuzumab among patients achieving a pathologic complete response (pCR) after trastuzumab-based neoadjuvant systemic therapy (NST).

Patients and methods:

Patients with primary HER2-positive breast cancer treated with trastuzumab-based NST were categorised according to adjuvant trastuzumab administration and pCR status. Adjuvant trastuzumab became standard of care in 2006, this was the main reason patients in our cohort did not receive adjuvant trastuzumab. Kaplan–Meier was used to estimate survival. A test for interaction between adjuvant trastuzumab and pCR was completed.

Findings:

Of 589 patients, 203 (34.5%) achieved a pCR. After surgery, 109 (18.5%) patients in the entire cohort did not receive adjuvant trastuzumab. Among patients achieving a pCR, 31.3% received adjuvant trastuzumab compared with 68.8% among those who did not achieve a pCR (P=0.0006). Among patients achieving pCR, adjuvant trastuzumab did not further improve overall survival (OS) or relapse-free survival (RFS) (P=0.35 and P=0.93, respectively). Any benefit of adjuvant trastuzumab in OS and RFS among patients without a pCR did not achieve statistical significance (P=0.3 and P=0.44, respectively).

Conclusions:

In this cohort, patients treated with trastuzumab-based NST who achieved a pCR have excellent outcome regardless of whether they received adjuvant trastuzumab.     

Predictors of recurrence in breast cancer patients with a pathologic complete response after neoadjuvant chemotherapy

Background:

Although a pathologic complete response (pCR) after neoadjuvant chemotherapy is associated with favourable outcomes, a small proportion of patients with pCR have recurrence. This study was designed to identify factors predictive of recurrence in patients with pCR.

Methods:

A total of 449 breast cancer patients received neoadjuvant chemotherapy, and 88 evaluable patients had a pCR, defined as no evidence of invasive carcinoma in the breast at surgery. The clinical stage was II in 61 patients (69%), III in 27 (31%). All patients received taxanes and 92% received anthracyclines. Among 43 patients with HER2-positive tumours, 27 received trastuzumab. Cox regression analyses were performed to identify predictors of recurrence.

Results:

Median follow-up was 46.0 months. There were 12 recurrences, including 8 distant metastases. The rate of locoregional recurrence was 10.4% after breast-conserving surgery, as compared with 2.5% after mastectomy. Multivariate analysis revealed that axillary metastases (hazard ratio (HR), 13.6; P<0.0001) and HER2-positive disease (HR, 5.0; P<0.019) were significant predictors of recurrence. Five of six patients with both factors had recurrence. Inclusion of trastuzumab was not an independent predictor among patients with HER2-positive breast cancer.

Conclusion:

Our study results suggest that HER2 status and axillary metastases are independent predictors of recurrence in patients with pCR.     

Effects of lapatinib monotherapy: results of a randomised phase II study in therapy-naive patients with locally advanced squamous cell carcinoma of the head and neck

Background:

Lapatinib is a dual inhibitor of epidermal growth factor receptor (EGFR) and human EGFR-2 (HER-2) tyrosine kinases. This study investigated the pharmacodynamic and clinical effects of lapatinib in patients with locally advanced squamous cell carcinoma of the head and neck (SCCHN).

Methods:

In total, 107 therapy-naive patients with locally advanced SCCHN were randomised (2 : 1) to receive lapatinib or placebo for 2–6 weeks before chemoradiation therapy (CRT). Endpoints included apoptosis and proliferation rates, clinical response, and toxicity.

Results:

Versus placebo, lapatinib monotherapy did not significantly increase apoptosis detected by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick-end labelling or caspase-3 assays. A statistically significant decrease in proliferation using Ki67 assay was observed (P=0.030). In a subset of 40 patients that received ⩾4 weeks of lapatinib or placebo, objective response rate (ORR) was 17% (n=4/24) vs 0% (n=0/16). In the lapatinib single-agent responders, all had EGFR overexpression, 50% had EGFR amplification, and 50% had HER2 expression by immunohistochemistry (including one patient with HER2 amplification). However, these patients showed variable modulation of apoptosis, proliferation, and phosphorylated EGFR on drug treatment. Following CRT, there was a statistically non-significant difference in ORR between lapatinib (70%) and placebo (53%). There was no clear correlation between changes in apoptosis or proliferation and response to chemoradiation. Mucosal inflammation, asthenia, odynophagia, and dysphagia were the most commonly reported adverse events with lapatinib.

Conclusion:

Short-term lapatinib monotherapy did not demonstrate apoptotic changes, but provided evidence of clinical activity in locally advanced SCCHN, and warrants further investigation in this disease.     

Pilot trial of paclitaxel-trastuzumab adjuvant therapy for early stage breast cancer: a trial of the ECOG-ACRIN cancer research group (E2198)

Background:

Blockade of human epidermal growth factor receptor type 2 (HER2) has dramatically improved outcome for patients with HER2-positive breast cancer. Trastuzumab, an anti-HER2 monoclonal antibody, has previously demonstrated improvement in overall survival (OS) in patients with metastatic and early stage HER2-positive breast cancer. However, trastuzumab can cause congestive heart failure (CHF) with an increased frequency for patients who have also received an anthracycline. The current trial was designed to evaluate the impact of the duration of trastuzumab on CHF.

Methods:

E2198 included 227 eligible women with histologically confirmed stage II or IIIA HER2-positive breast cancer. The patients were randomised to receive 12 weeks of paclitaxel and trastuzumab followed by four cycles of doxorubicin and cyclophosphamide (abbreviated Arm) or the aforementioned treatment with additional 1 year of trastuzumab (conventional Arm). The primary end point was to evaluate the safety of this variable duration of trastuzumab therapy, particularly cardiac toxicity defined as CHF or left ventricular ejection fraction decrease >10%. Secondary end points included disease-free survival (DFS) and OS.

Results:

Compared with 12-week treatment with trastuzumab, 1 year of trastuzumab-based therapy did not increase the frequency or severity of cardiac toxicity: three patients on the abbreviated Arm and four on the conventional Arm experienced CHF. The 5-year DFS was 76% and 73% for the abbreviated and conventional Arms, respectively, with a hazard ratio (HR) of 1.3 (95% CI: 0.8–2.1; P=0.3). There was also no statistically significance difference in OS (HR, 1.4; P=0.3).

Conclusions:

Compared with 12 weeks of treatment, 1 year of treatment with trastuzumab did not significantly increase the risk of cardiac toxicity. Although not powered for efficacy comparisons, the longer duration of trastuzumab therapy did not demonstrate a signal for marked superiority.     

Role of HER3 expression and PTEN loss in patients with HER2-overexpressing metastatic breast cancer (MBC) who received taxane plus trastuzumab treatment

Background:

The aim of this study was to investigate the role of human epidermal growth factor receptor (HER3) and PTEN expression in patients with HER2-overexpressing metastatic breast cancer (MBC).

Methods:

One hundred twenty-five MBC patients who were treated with taxane plus trastuzumab chemotherapy as first-line therapy were included in this analysis. Immunohistochemical (IHC) staining with HER3 and PTEN antibodies were conducted retrospectively.

Results:

Patients who had negative HER3 staining (62.4%) had a better progression-free survival (PFS) than did those who had positive HER3 staining (P=0.001; median PFS, 21 vs 11 months). Patients who had a PTEN score >20 (78.1%) showed longer PFS than did those with a PTEN score ⩽20 (P=0.006; median PFS, 13 vs 9 months). Patients who had a PTEN score >20 exhibited a longer overall survival (OS) than did those with a PTEN score ⩽20 (P=0.005; median OS, 48 vs 25 months). HER3 negativity and PTEN loss were identified as independent risk factors for PFS. PTEN loss was identified as an independent risk factor for OS.

Conclusion:

HER3 and PTEN expressions may be predictive markers, and PTEN expression may be a predictive and prognostic biomarker for trastuzumab treatment in HER2-positive MBCs.     

Addition of GM-CSF to trastuzumab stabilises disease in trastuzumab-resistant HER2+ metastatic breast cancer patients

Background:

One of the proposed mechanisms of trastuzumab-induced regression of human epidermal growth factor receptor 2-positive (HER2+) tumours includes facilitation of antibody-dependent cell-mediated cytotoxicity (ADCC). Granulocyte-macrophage colony-stimulating factor (GM-CSF) mediates ADCC. We presented our pilot study of adding GM-CSF to trastuzumab in patients with trastuzumab-resistant HER2+ metastatic breast cancer.

Methods:

Patients with HER2+ metastatic breast cancer that progressed after trastuzumab +/− chemotherapy were continued on trastuzumab 2 mg kg^–1 intravenous weekly and GM-CSF 250 μg m^–2 subcutaneous daily. Patients were assessed for response every 8 weeks. Treatment was continued until disease progression or intolerable toxicity.

Results:

Seventeen patients were evaluable (median age 48 years, range 27–75 years). The median number of metastatic sites was 2 (range 1–3); the most common site was the liver (n=10). The median number of prior regimens for metastatic disease was 2 (range 1–5). No objective disease response was observed, but five patients (29%) had stable disease for a median duration of 15.8 (range 10–53.9) weeks. The most common adverse event was rash at the injection site. No grade 4 or irreversible adverse event was seen.

Conclusion:

The addition of GM-CSF to trastuzumab alone had a modest clinical benefit and acceptable safety profile in heavily pretreated patients with trastuzumab-resistant HER2+ metastatic breast cancer.     

Anthracycline rechallenge using pegylated liposomal doxorubicin in patients with metastatic breast cancer: a pooled analysis using individual data from four prospective trials

Background:

The aim of this study was to determine the activity of anthracycline rechallenge using pegylated liposomal doxorubicin (PLD) in patients with metastatic breast cancer (MBC) previously treated with conventional anthracyclines.

Methods:

Pooled individual data from four prospective trials were used, and the primary end point of the pooled analysis was clinical benefit rate (CBR). The studies comprised 935 patients, of whom 274 had received PLD in the metastatic setting after prior exposure to conventional anthracyclines (rechallenge population).

Results:

The majority of patients were heavily pretreated. Previous anthracycline therapy was administered in the adjuvant (14%) or metastatic setting (46%), or both (40%). The overall CBR from rechallenge with PLD was 37.2% (95% CI, 32.4–42.0). In univariate analyses, the CBR was significantly higher in patients with less exposure to prior chemotherapy, in taxane-naive patients, and in patients with a favourable Eastern Cooperative Group performance status of 0 vs 1 vs 2 (53.3 vs 35.5 vs 18.2% P<0.001). In multivariate analyses, performance status proved to be the only independent predictor of the CBR achieved with PLD rechallenge (P=0.038). There was no statistically significant difference in CBR regarding the setting, cumulative dose of and/or resistance to prior anthracyclines, or time since prior anthracycline administration.

Conclusion:

Anthracycline rechallenge using PLD is effective in patients with MBC who have a favourable performance status, regardless of setting, resistance, cumulative dose or time since prior conventional anthracycline therapy.     

Prognostic and predictive values of EGFR overexpression and EGFR copy number alteration in HER2-positive breast cancer

Background:

Epidermal growth factor receptor (EGFR) is overexpressed in a subset of human epidermal growth factor receptor 2 (HER2)-positive breast cancers, and coexpression of HER2 and EGFR has been reported to be associated with poor clinical outcome. Moreover, interaction between HER2 and EGFR has been suggested to be a possible basis for trastuzumab resistance.

Methods:

We analysed the clinical significance of EGFR overexpression and EGFR gene copy number alterations in 242 HER2-positive primary breast cancers. In addition, we examined the correlations between EGFR overexpression, trastuzumab response and clinical outcome in 447 primary, and 112 metastatic HER2-positive breast cancer patients treated by trastuzumab.

Results:

Of the 242 primary cases, the level of EGFR overexpression was 2+ in 12.7% and 3+ in 11.8%. High EGFR gene copy number was detected in 10.3%. Epidermal growth factor receptor overexpression was associated with hormone receptor negativity and high Ki-67 proliferation index. In survival analyses, EGFR overexpression, but not high EGFR copy number, was associated with poor disease-free survival in all patients, and in the subgroup not receiving adjuvant trastuzumab. In 447 HER2-positive primary breast cancer patients treated with adjuvant trastuzumab, EGFR overexpression was also an independent poor prognostic factor. However, EGFR overexpression was not associated with trastuzumab response, progression-free survival or overall survival in the metastatic setting.

Conclusions:

Epidermal growth factor receptor overexpression, but not high EGFR copy number, is a poor prognostic factor in HER2-positive primary breast cancer. Epidermal growth factor receptor overexpression is a predictive factor for trastuzumab response in HER2-positive primary breast cancer, but not in metastatic breast cancer.     

Targeting both Notch and ErbB-2 signalling pathways is required for prevention of ErbB-2-positive breast tumour recurrence

Background:

We reported that Notch-1, a potent breast oncogene, is activated in response to trastuzumab and contributes to trastuzumab resistance in vitro. We sought to determine the preclinical benefit of combining a Notch inhibitor (γ-secretase inhibitor (GSI)) and trastuzumab in both trastuzumab-sensitive and trastuzumab-resistant, ErbB-2-positive, BT474 breast tumours in vivo. We also studied if the combination therapy of lapatinib plus GSI can induce tumour regression of ErbB-2-positive breast cancer.

Methods:

We generated orthotopic breast tumour xenografts from trastuzumab- or lapatinib-sensitive and trastuzumab-resistant BT474 cells. We investigated the antitumour activities of two distinct GSIs, LY 411 575 and MRK-003, in vivo.

Results:

Our findings showed that combining trastuzumab plus a GSI completely prevented (MRK-003 GSI) or significantly reduced (LY 411 575 GSI) breast tumour recurrence post-trastuzumab treatment in sensitive tumours. Moreover, combining lapatinib plus MRK-003 GSI showed significant reduction of tumour growth. Furthermore, a GSI partially reversed trastuzumab resistance in resistant tumours.

Conclusion:

Our data suggest that a combined inhibition of Notch and ErbB-2 signalling pathways could decrease recurrence rates for ErbB-2-positive breast tumours and may be beneficial in the treatment of recurrent trastuzumab-resistant disease.     

Increased signalling of EGFR and IGF1R, and deregulation of PTEN/PI3K/Akt pathway are related with trastuzumab resistance in HER2 breast carcinomas

Background:

Trastuzumab resistance hampers its well-known efficacy to control HER2-positive breast cancer. The involvement of PI3K/Akt pathway in this mechanism is still not definitively confirmed.

Methods:

We selected 155 patients treated with trastuzumab after development of metastasis or as adjuvant/neoadjuvant therapy. We performed immunohistochemistry for HER2, ER/PR, epidermal growth factor 1-receptor (EGFR), α-insulin-like growth factor 1-receptor (IGF1R), phosphatase and tensin homologue (PTEN), p110α, pAkt, pBad, pmTOR, pMAPK, MUC1, Ki67, p53 and p27; mutational analysis of PIK3CA and PTEN, and PTEN promoter hypermethylation.

Results:

We found 46% ER/PR-positive tumours, overexpression of EGFR (15%), α-IGF1R (25%), p110α (19%), pAkt (28%), pBad (22%), pmTOR (23%), pMAPK (24%), MUC1 (80%), PTEN loss (20%), and PTEN promoter hypermethylation (20%). PIK3CA and PTEN mutations were detected in 17% and 26% tumours, respectively. Patients receiving adjuvant trastuzumab with α-IGF1R or pBad overexpressing tumours presented shorter progression-free survival (PFS) (all P⩽0.043). Also, p110α and mTOR overexpression, liver and brain relapses implied poor overall survival (OS) (all P⩽0.041). In patients with metastatic disease, decreased PFS correlated with p110α expression (P=0.024), whereas for OS were the presence of vascular invasion and EGFR expression (P⩽0.019; Cox analysis).

Conclusion:

Our results support that trastuzumab resistance mechanisms are related with deregulation of PTEN/PI3K/Akt/mTOR pathway, and/or EGFR and IGF1R overexpression in a subset of HER2-positive breast carcinomas.     

Src,a potential target for overcoming trastuzumab resistance in HER2-positive breast carcinoma

Background:

Src is a non-receptor tyrosine kinase involved in signalling and crosstalk between growth-promoting pathways. We aim to investigate the relationship of active Src in response to trastuzumab of HER2-positive breast carcinomas.

Methods:

We selected 278 HER2-positive breast cancer patients with (n=154) and without (n=124) trastuzumab treatment. We performed immunohistochemistry on paraffin-embedded tissue microarrays of active Src and several proteins involved in the PI3K/Akt/mTOR pathway, PIK3CA mutational analysis and in vitro studies (SKBR3 and BT474 cancer cells). The results were correlated with clinicopathological factors and patients'' outcome.

Results:

Increased pSrc-Y416 was demonstrated in trastuzumab-resistant cells and in 37.8% of tumours that correlated positively with tumour size, necrosis, mitosis, metastasis to the central nervous system, p53 overexpression and MAPK activation but inversely with EGFR and p27. Univariate analyses showed an association of increased active Src with shorter survival in patients at early stage with HER2/hormone receptor-negative tumours treated with trastuzumab.

Conclusions:

Src activation participates in trastuzumab mechanisms of resistance and indicates poor prognosis, mainly in HER2/hormone receptor-negative breast cancer. Therefore, blocking this axis may be beneficial in those patients.     

Multicentre phase II trial of trastuzumab and capecitabine in patients with HER2 overexpressing metastatic pancreatic cancer

Background:

New therapeutic options for metastatic pancreatic cancer are urgently needed. In pancreatic cancer, overexpression of the epidermal growth factor receptor 2 (HER2) has been reported in up to 45%. This multicentre phase II study investigated the efficacy and toxicity of the HER2 antibody trastuzumab combined with capecitabine in the patients with pancreatic cancer and HER2 overexpression.

Methods:

Primary endpoint was progression-free survival (PFS) after 12 weeks. A total of 212 patients were screened for HER2 expression.

Results:

Immunohistochemical (IHC) HER2 expression was: 83 (40%) grade 0, 71 (34%) grade 1, 31 (15%) grade 2, 22 (11%) grade 3. A total of 17 patients with IHC +3 HER2 expression or gene amplification could be assessed for the treatment response. Grade 3/4 treatment toxicities were: each 7% leucopenia, diarrhoea, nausea and hand-foot syndrome. Progression-free survival after 12 weeks was 23.5%, median overall survival (OS) 6.9 months.

Conclusion:

This study demonstrates +3 HER2 expression or gene amplification in 11% of patients. Contrary to breast and gastric cancer, only 7 out of 11 (64%) patients with IHC +3 HER2 expression showed gene amplification. Although the therapy was well tolerated, PFS and OS did not perform favourably compared with standard chemotherapy. Together, we do not recommend further evaluation of anti-HER2 treatment in patients with metastatic pancreatic cancer.     

Trastuzumab or lapatinib with standard chemotherapy for HER2-positive breast cancer: results from the GEICAM/2006-14 trial

Background:

The addition of trastuzumab (T) and lapatinib (L) to neoadjuvant chemotherapy increases the pathological complete response (pCR) rate in patients with human epidermal growth factor receptor 2 (HER2)-positive early breast cancer. We investigated the efficacy of T or L with neoadjuvant chemotherapy and specific efficacy biomarkers.

Methods:

Patients with stages I–III (including inflammatory) HER2-positive breast cancer were randomised to receive epirubicin (E) plus cyclophosphamide (C) × 4 cycles followed by docetaxel (D) plus either T (EC-DT) or L (EC-DL). End points included pCR (primary), clinical response, toxicity, and pCR-predictive biomarkers.

Results:

We randomised 102 patients to EC-DT (50) and EC-DL (52). Median age was 48, 56% were premenopausal and 58% had oestrogen receptor (ER)-positive tumours. Pathological complete response in breast was 52.1% (95% CI:38.0–66.2%) for EC-DT and 25.5% (95% CI:13.5–37.5%) for EC-DL (P=0.0065). Pathological complete response in breast and axilla was 47.9% for EC-DT and 23.5% for EC-DL (P=0.011). Grade 3–4 toxicity did not differ across treatments, except for diarrhoea (2% in EC-DT vs 13.5% in EC-DL, P=0.030). Multivariate analyses showed that treatment (P=0.036) and ER (P=0.014) were the only predictors of pCR in both groups.

Conclusion:

EC-DT exhibited higher efficacy and lower toxicity than EC-DL. Of the different biomarkers studied, only the absence of ER expression was associated with increased pCR.     

Pathological complete response and prognosis after neoadjuvant chemotherapy for HER2-positive breast cancers before and after trastuzumab era: results from a real-life cohort

Background:

Trastuzumab was introduced a decade ago and has improved outcomes for HER2-positive breast cancer. We investigated the factors predictive of pathological complete response (pCR), prognostic factors for disease-free survival (DFS), and interactions between pCR and DFS after neoadjuvant treatment.

Methods:

We identified 287 patients with primary HER2-positive breast cancers given neoadjuvant chemotherapy (NAC) between 2002 and 2011. Univariate and multivariate analyses of clinical and pathological factors associated with pCR and DFS were performed.

Results:

pCR rates differed between patients receiving neoadjuvant trastuzumab treatment or not (47.7% versus 19.3%, P<0.0001). DFS also differed significantly between patients receiving adjuvant trastuzumab or not (hazard ratio=4.84, 95% CI (2.52; 9.31), P<0.001). We analysed 199 patients given neoadjuvant and adjuvant trastuzumab. Multivariate analysis identified older age and hormone receptor-negative tumours as independent predictors of pCR. T stage (hazard ratio=2.55, 95% CI (1.01; 6.48), P=0.05) and strict pCR (hazard ratio=9.15, 95% CI (1.22; 68.83), P=0.03) were independent predictors of DFS. The latter association was significant in the HR-negative subgroup (P=0.02) but not in the HR-positive subgroup (P=0.12).

Conclusions:

Major pCR and DFS gains in HER2-positive BC were observed since ‘trastuzumab'' era. Further improvements rely on the enrollment of accurately selected patients into clinical trials.     

Detection of HER2 amplification in circulating free DNA in patients with breast cancer

Background:

Human epidermal growth factor receptor 2 (HER2) is amplified and overexpressed in 20–25% of breast cancers. This study investigated circulating free DNA (cfDNA) for detection of HER2 gene amplification in patients with breast cancer.

Methods:

Circulating free DNA was extracted from plasma of unselected patients with primary breast cancer (22 before surgery and 68 following treatment), 30 metastatic patients and 98 female controls using the QIAamp Blood DNA Mini Kit (Qiagen). The ratio of HER2 to an unamplified reference gene (contactin-associated protein 1 (CNTNAP1)) was measured in cfDNA samples by quantitative PCR (qPCR) using SK-BR-3 cell line DNA as a positive control.

Results:

We validated the qPCR assay with DNA extracted from 23 HER2 3+ and 40 HER2-negative tumour tissue samples; the results agreed for 60 of 63 (95.2%) tumours. Amplification was detected in cfDNA for 8 of 68 patients following primary breast cancer treatment and 5 of 30 metastatic patients, but was undetected in 22 patients with primary breast cancer and 98 healthy female controls. Of the patients with amplification in cfDNA, 10 had HER2 3+ tumour status by immunohistochemistry.

Conclusions:

The results demonstrate for the first time the existence of amplified HER2 in cfDNA in the follow-up of breast cancer patients who are otherwise disease free. This approach could potentially provide a marker in patients with HER2-positive breast cancer.     

Pathological complete response and survival according to the level of HER-2 amplification after trastuzumab-based neoadjuvant therapy for breast cancer

Background:

We analysed whether the level of human epidermal growth factor receptor-2 (HER-2) amplification significantly influenced either pathological complete response (pCR) or recurrence-free survival (RFS) and overall survival (OS) after trastuzumab-based neoadjuvant therapy.

Methods:

In all, 99 patients with an HER-2-amplified breast tumour treated with trastuzumab-based neoadjuvant therapy were included. Tumours were classified as low amplified (LA; 6–10 signals per nuclei) or highly amplified (HA; >10 signals). Pathological response was assessed according to Chevallier''s classification (pCR was defined as grade 1 or 2). Median follow-up lasted 46 months (6–83). Cox uni- and multivariate analyses were performed.

Results:

In all, 33 tumour samples were LA and 66 were HA. The pCR in HA tumours was significantly higher than in LA tumours (55% vs 24%, P=0.005), whereas no association was found between the pCR rate and tumour stage, grade or hormone receptor status. In multivariate analysis, the pathological nodal status (P=0.005) and adjuvant trastuzumab (P=0.037) were independently associated with RFS, whereas the level of HER-2 amplification nearly reached statistical significance (P=0.057). There was no significant difference between LA and HA tumours for OS (P=0.22, log-rank).

Conclusion:

The level of HER-2 gene amplification significantly influenced pCR but not RFS or OS in non-metastatic breast cancer treated with trastuzumab-based neoadjuvant therapy. However, RFS in patients with HA tumours tended to be shorter.