PIK3CA mutations are associated with lower rates of pathologic complete response to anti-human epidermal growth factor receptor 2 (her2) therapy in primary HER2-overexpressing breast cancer.

PURPOSE: Phosphatidylinositol 3-kinase (PI3K)/AKT pathway aberrations are common in breast cancer, with mutations in PIK3CA being the most common. This study investigated the association between PIK3CA genotype and pathologic complete response (pCR) rates in human epidermal growth factor receptor 2 (HER2)-positive breast cancer treated with either dual or single anti-HER2 treatment in addition to neoadjuvant chemotherapy. PATIENTS AND METHODS: PIK3CA mutations in 504 tumor samples from participants in the neoadjuvant GeparQuattro, GeparQuinto, and GeparSixto studies were evaluated. All HER2-positive patients received either trastuzumab or lapatinib or the combination plus anthracycline-taxane chemotherapy. PIK3CA mutations were evaluated in formalin-fixed, paraffin-embedded tissues from core biopsies with a tumor cell content of ≥ 20% by using classical Sanger sequencing of exon 9 and exon 20. RESULTS: Overall, 21.4% of the patients harbored a PIK3CA mutation. Detection of a PIK3CA mutation was significantly associated with a lower pCR rate (19.4% with PIK3CA mutation v 32.8% with PIK3CA wild-type; odds ratio [OR], 0.49; 95% CI, 0.29 to 0.83; P = .008). In the 291 hormone receptor (HR) -positive tumors, pCR rate was 11.3% with a PIK3CA mutation compared with 27.5% with PIK3CA wild-type (OR, 0.34; 95% CI, 0.15 to 0.78; P = .011). In 213 patients with HR-negative tumors, pCR rate was 30.4% with PIK3CA mutation and 40.1% without (OR, 0.65; 95% CI, 0.32 to 1.32; P = .233; interaction test P = .292). In multivariable analysis, HR status and PIK3CA status provided independent predictive information. In patients with PIK3CA mutation, the pCR rates were 16%, 24.3%, and 17.4% with lapatinib, trastuzumab, and the combination, respectively (P = .654) and in the wild-type group, they were 18.2%, 33.%, and 37.1%, respectively (P = .017). Disease-free survival and overall survival were not statistically significantly different between patients with mutant and wild-type PIK3CA. CONCLUSION: HER2-positive breast carcinomas with a PIK3CA mutation are less likely to achieve a pCR after neoadjuvant anthracycline-taxane-based chemotherapy plus anti-HER2 treatment, even if a dual anti-HER2 treatment is given.

Neoadjuvant carboplatin in patients with triple-negative and HER2-positive early breast cancer (GeparSixto; GBG 66): a randomised phase 2 trial.

BACKGROUND: Preclinical data suggest that triple-negative breast cancers are sensitive to interstrand crosslinking agents, and that synergy may exist for the combination of a taxane, trastuzumab, and a platinum salt for HER2-positive breast cancer. We therefore aimed to assess the efficacy of the addition of carboplatin to neoadjuvant therapy for triple-negative and HER2-positive breast cancer. METHODS: Patients with previously untreated, non-metastatic, stage II-III, triple-negative breast cancer and HER2-positive breast cancer were enrolled. Patients were treated for 18 weeks with paclitaxel (80 mg/m(2) once a week) and non-pegylated liposomal doxorubicin (20 mg/m(2) once a week). Patients with triple-negative breast cancer received simultaneous bevacizumab (15 mg/kg intravenously every 3 weeks). Patients with HER2-positive disease received simultaneous trastuzumab (8 mg/kg initial dose with subsequent doses of 6 mg/kg intravenously every 3 weeks) and lapatinib (750 mg daily). Patients were randomly assigned in a 1:1 ratio with dynamic allocation and minimisation, stratified by biological subtype and Ki-67 level to receive, at the same time as the backbone regimens, either carboplatin (AUC 1·5 [2·0 for the first 329 patients] once a week) or no carboplatin. The primary endpoint the proportion of patients who achieved a pathological complete response (defined as ypT0 ypN0), analysed for all patients who started treatment; a p value of less than 0·2 was deemed significant for the primary endpoint. This trial is registered with ClinicalTrials.gov, number NCT01426880. FINDINGS: 296 patients were randomly assigned to receive carboplatin and 299 to no additional carboplatin, of whom 295 and 293 started treatment, respectively. In this final analysis, 129 patients (43·7%, 95% CI 38·1-49·4) in the carboplatin group achieved a pathological complete response, compared with 108 patients (36·9%, 31·3-42·4) without carboplatin (odds ratio 1·33, 95% CI 0·96-1·85; p=0·107). Of the patients with triple-negative breast cancer, 84 (53·2%, 54·4-60·9) of 158 patients achieved a pathological complete response with carboplatin, compared with 58 (36·9%, 29·4-44·5) of 157 without (p=0·005). Of the patients with HER2-positive tumours, 45 (32·8%, 25·0-40·7) of 137 patients achieved a pathological complete response with carboplatin compared with 50 (36·8%, 28·7-44·9) of 136 without (p=0·581; test for interaction p=0·015). Haematological and non-haematological toxic effects that were significantly more common in the carboplatin group than in the no-carboplatin group included grade 3 or 4 neutropenia (192 [65%] vs 79 [27%]), grade 3 or 4 anaemia (45 [15%] vs one [<1%]), grade 3 or 4 thrombocytopenia (42 [14%] vs one [<1%]), and grade 3 or 4 diarrhoea (51 [17%] vs 32 [11%]); carboplatin was more often associated with dose discontinuations (141 [48%] with carboplatin and 114 [39%] without carboplatin; p=0·031). The frequency of grade 3 or 4 haematological events decreased from 82% (n=135) to 70% (n=92) and grade 3 or 4 non-haematological events from 78% (n=128) to 59% (n=77) in the carboplatin arm when the dose of carboplatin was reduced from AUC 2·0 to 1·5. INTERPRETATION: The addition of neoadjuvant carboplatin to a regimen of a taxane, an anthracycline, and targeted therapy significantly increases the proportion of patients achieving a pathological complete response. This regimen seems to increase responses in patients with triple-negative breast cancer, but not in those with HER2-positive breast cancer. FUNDING: GlaxoSmithKline, Roche, and Teva.

Neoadjuvant chemotherapy with paclitaxel and everolimus in breast cancer patients with non-responsive tumours to epirubicin/cyclophosphamide (EC) ± bevacizumab - results of the randomised GeparQuinto study (GBG 44).

BACKGROUND: We tested the oral mammalian target of rapamycin (mTOR) inhibitor everolimus in addition to paclitaxel in patients with HER2-negative tumours not responding to initial neoadjuvant cytotoxic and anti-angiogenic treatment. METHODS: Patients with primary HER2-negative tumours received four neoadjuvant cycles of epirubicin/cyclophosphamide (EC) with or without bevacizumab. Patients without clinical response were randomised to receive weekly paclitaxel (80 mg/m(2)) with or without everolimus (5mg p.o. daily, after a step-wise dose-escalation starting from 2.5mg bid) for 12 weeks before surgery. To detect an increase in pathological complete response (pCR; ypT0 ypN0) from 5% to 12.1% (odds ratio 2.62) 566 patients had to be recruited. The trial was stopped prematurely due to completion of accrual in the main study. FINDINGS: Of 1948 patients initially starting neoadjuvant treatment 403 were randomised. A total of 18 (4.6%) patients, 7 (3.6%) treated with paclitaxel and everolimus and 11 (5.6%) treated with paclitaxel alone had a pCR (odds ratio 0.36 (OR) (95% confidence interval (CI), 0.24-1.6) p=0.34). Overall response rate in breast and lymph nodes at surgery was 52.2% after paclitaxel plus everolimus and 61.7% after paclitaxel alone (p=0.063). Breast conserving treatment was performed in 54.4% of patients with the combination treatment and 61.9% with paclitaxel alone (p=0.20). Mucosal inflammation, thrombocytopenia, neutropenia, infection, and skin rash were more frequent when everolimus was added to paclitaxel. INTERPRETATION: Neoadjuvant therapy with everolimus and paclitaxel for patients with HER2-negative disease unresponsive to EC with or without bevacizumab did not improve the pCR rate. Long-term outcome is awaited. FUNDING: Novartis, Roche, and Sanofi-Aventis.

Neutrophil gelatinase-associated lipocalin (NGAL) predicts response to neoadjuvant chemotherapy and clinical outcome in primary human breast cancer.

In our previous work we showed that NGAL, a protein involved in the regulation of proliferation and differentiation, is overexpressed in human breast cancer (BC) and predicts poor prognosis. In neoadjuvant chemotherapy (NACT) pathological complete response (pCR) is a predictor for outcome. The aim of this study was to evaluate NGAL as a predictor of response to NACT and to validate NGAL as a prognostic factor for clinical outcome in patients with primary BC. Immunohistochemistry was performed on tissue microarrays from 652 core biopsies from BC patients, who underwent NACT in the GeparTrio trial. NGAL expression and intensity was evaluated separately. NGAL was detected in 42.2% of the breast carcinomas in the cytoplasm. NGAL expression correlated with negative hormone receptor (HR) status, but not with other baseline parameters. NGAL expression did not correlate with pCR in the full population, however, NGAL expression and staining intensity were significantly associated with higher pCR rates in patients with positive HR status. In addition, strong NGAL expression correlated with higher pCR rates in node negative patients, patients with histological grade 1 or 2 tumors and a tumor size <40 mm. In univariate survival analysis, positive NGAL expression and strong staining intensity correlated with decreased disease-free survival (DFS) in the entire cohort and different subgroups, including HR positive patients. Similar correlations were found for intense staining and decreased overall survival (OS). In multivariate analysis, NGAL expression remained an independent prognostic factor for DFS. The results show that in low-risk subgroups, NGAL was found to be a predictive marker for pCR after NACT. Furthermore, NGAL could be validated as an independent prognostic factor for decreased DFS in primary human BC.

Cytoplasmic poly(adenosine diphosphate-ribose) polymerase expression is predictive and prognostic in patients with breast cancer treated with neoadjuvant chemotherapy.

PURPOSE: Poly(adenosine diphosphate-ribose) polymerase (PARP) plays a key role in DNA repair and cellular stress response. Inhibitors of PARP show promising clinical activity in metastatic, triple-negative or BRCA-mutated breast cancer. PATIENTS AND METHODS: We investigated cytoplasmic PARP (cPARP) and nuclear PARP (nPARP) expression by immunohistochemistry in 638 pretreatment biopsies from patients on the GeparTrio study and evaluated its predictive and prognostic value after neoadjuvant anthracycline/taxane-based chemotherapy. RESULTS: cPARP expression was high in 23.7%, intermediate in 50.9%, and negative in 25.4% of tumors. High cPARP expression was significantly correlated with nonlobular histology (P < .001), undifferentiated grade (P < .001), positive nodal status (P = .049), and negative hormone receptor (HR) status (P < .001) but not with human epidermal growth factor receptor 2 (HER2) status. Expression was high in 35.5% of triple-negative tumors, 24.6% of HER2-positive tumors, and 18.0% of HR-positive/HER2-negative tumors (P < .001). Pathologic complete response (pCR) rates were 26.5%, 19.1%, and 8.0% in patients with high, intermediate, or negative expression, respectively (P < .001). This predictive effect was most prominent in HR-positive tumors (P = .035) or HER2-negative tumors (P < .001). High cPARP expression was a negative, but not independent, prognostic factor for disease-free survival (DFS; P = .0025) and overall survival (OS; P = .0022). cPARP expression was highly prognostic in patients without a pCR (DFS, P < .001; OS, P < .001) and in patients with HR-positive tumors (DFS, P < .001; OS, P < .001). No such correlations were found for nPARP expression. CONCLUSION: High cPARP expression correlates with aggressive tumor pattern and predicts high sensitivity to neoadjuvant taxane/anthracycline-based chemotherapy but also unfavorable long-term prognosis. As a potential target for PARP inhibitors, cPARP-positive breast cancer might become a new, clinically relevant entity.

Effect of neoadjuvant anthracycline-taxane-based chemotherapy in different biological breast cancer phenotypes: overall results from the GeparTrio study.

In order to explore the effect of neoadjuvant chemotherapy (NACT) on clinical mid-course and pathological complete response (pCR) at surgery in different biological breast cancer subtypes. The GeparTrio study included 2,072 patients with operable or locally advanced breast cancer. After two cycles with docetaxel, doxorubicin and cyclophosphamide (TAC) patients were randomized according to their clinical response. Clinical and biological factors were assessed for predicting clinically mid-course response and pCR at surgery. The overall pCR rate, defined as no invasive residuals in breast and axilla, was 20.5%. The highest pCR rate of 57% was observed in patients below 40 years of age with triple negative or grade 3 tumors. Independent factors for mid-course response and pCR were: young age, non-T4 tumors, high grade, and hormone receptor status, the strongest single predictive factor. Within the biological subtypes, grading was an independent factor to predict pCR for luminal tumors, clinical tumor stage for the HER2 like tumors and age for the triple negative ones. Grading gave independent information for mid-course response within the triple negative group. No factor predicted mid-course response within the other groups. Grading and age can identify subgroups within the luminal and triple negative patients who have an increased benefit from NACT.