Association between gain-of-function mutations in PIK3CA and resistance to HER2-targeted agents in HER2-amplified breast cancer cell lines

BackgroundThe mechanism of resistance to human epidermal growth factor receptor 2 (HER2)-targeted agents has not been fully understood. We investigated the influence of PIK3CA mutations on sensitivity to HER2-targeted agents in naturally derived breast cancer cells.Materials and methodsWe examined the effects of Calbiochem (CL)-387,785, HER2 tyrosine kinase inhibitor, and trastuzumab on cell growth and HER2 signaling in eight breast cancer cell lines showing HER2 amplification and trastuzumab-conditioned BT474 (BT474-TR).ResultsFour cell lines with PIK3CA mutations (E545K and H1047R) were more resistant to trastuzumab than the remaining four without mutations (mean percentage of control with 10 μg/ml trastuzumab: 58% versus 92%; P = 0.010). While PIK3CA-mutant cells were more resistant to CL-387,785 than PIK3CA-wild-type cells (mean percentage of control with 1 μm CL-387,785: 21% versus 77%; P = 0.001), CL-387,785 retained activity against BT474-TR. Growth inhibition by trastuzumab and CL-387,785 was more closely correlated with changes in phosphorylation of S6K (correlation coefficient, 0.811) than those of HER2, Akt, or ERK1/2. Growth of most HER2-amplified cells was inhibited by LY294002, regardless of PIK3CA genotype.Conclusions:PIK3CA mutations are associated with resistance to HER2-targeted agents. PI3K inhibitors are potentially effective in overcoming trastuzumab resistance caused by PIK3CA mutations. S6K phosphorylation is a possibly useful pharmacodynamic marker in HER2-targeted therapy.     

HER3 expression in patients with primary colorectal cancer and corresponding lymph node metastases related to clinical outcome

AimTo evaluate the expression and prognostic value of the epidermal growth factor receptor HER3 in patients with primary colorectal cancer (CRC) and corresponding lymph node metastases.Patient and methodsHER3 expression was analysed immunohistochemically (IHC) in primary tumours and in corresponding lymph node metastases from 236 patients with stage II and III CRC. In 58 primary tumours, fluorescence in situ hybridisation (FISH) detection was performed.ResultsHER3 was detected at high frequency in the cell membrane. Seventy percent of the primary tumours had a high HER3 expression compared to 75% in the lymph node metastases. HER3 expression in the primary tumour was an independent prognostic factor for overall survival in the entire group of patients (p = 0.026) and in the subgroup of patients with colon cancer stage II (p = 0.030). A high HER3 expression in the primary tumour was associated with worse clinical outcome. The expression of HER3 was homogenous within the primary tumour (r = 0.9, p < 0.0001) and correlated with the HER3 expression in corresponding lymph node metastases (r = 0.6, p < 0.0001). No gene amplification with respect to HER3 was seen in primary tumours using FISH analysis.ConclusionA high HER3 expression was found in 70% of the primary CRC tumours and in 75% of the corresponding lymph node metastases. HER3 expression in the tumour was an independent prognostic factor, where a high HER3 expression was associated with worse clinical outcome. There was a correlation in HER3 expression between primary tumour and corresponding lymph node metastases.     

Tumor-infiltrating lymphocytes in patients with HER2-positive breast cancer treated with neoadjuvant chemotherapy plus trastuzumab,lapatinib or their combination: A meta-analysis of randomized controlled trials

BackgroundA relationship between baseline tumor-infiltrating lymphocytes (TIL) and outcomes has been described in HER2-positive breast cancer. Nevertheless, the magnitude of this association and whether this effect differs based on the type of anti-HER2 agent remain controversial. This meta-analysis investigated the association between baseline TIL and pathologic complete response (pCR) rates in HER2-positive breast cancer patients treated with neoadjuvant chemotherapy plus trastuzumab and lapatinib either alone or in combination.MethodsA literature search covering PubMed, Embase and the Cochrane library up to October 31, 2016 identified randomized, controlled trials investigating neoadjuvant chemotherapy plus trastuzumab and lapatinib either alone or in combination where published data for pCR based on pre-treatment TIL scores were available. Two subgroups were considered: high baseline TIL vs. non-high TIL, according to each study definition. Summary risk estimates (odds ratio) and 95% confidence intervals (CI) were calculated for pCR using pre-treatment TIL levels for each trial. Pooled analyses were conducted using random and fixed effects models. Interaction P-values were computed using a Monte Carlo permutation test.ResultsA total of 5 studies (N = 1256 patients) were included. Overall, high TIL subgroup was associated with a significantly increased pCR rate (OR 2.46; 95% CI 1.36–4.43; P = 0.003). No interaction was observed between TIL subgroup (high vs. non-high TIL) and response to anti-HER2 agent(s) (trastuzumab vs. lapatinib vs. their combination; P = 0.747) and chemotherapy (anthracycline and taxanes vs. taxanes only; P = 0.201). A stronger association between high TIL subgroup and pCR rates was observed when examining only the 4 studies using anthracycline- and taxane- based neoadjuvant chemotherapy and the 60% cut-off for high TIL (N = 869, NeoALTTO excluded) with an OR of 2.88 (95% CI 2.03–4.08; P < 0.001).ConclusionsIn HER2-positive breast cancer, high baseline TIL are associated with increased pCR probability irrespective of neoadjuvant anti-HER2 agent(s) and chemotherapy regimens used.     

Impact of genomic alterations on lapatinib treatment outcome and cell-free genomic landscape during HER2 therapy in HER2+ gastric cancer patients

BackgroundTo identify predictive markers for responders in lapatinib-treated patients and to demonstrate molecular changes during lapatinib treatment via cell-free genomics.Patients and methodsWe prospectively evaluated the efficacy of combining lapatinib with capecitabine and oxaliplatin as first line neoadjuvant therapy in patients with previously untreated, HER2-overexpressing advanced gastric cancer. A parallel biomarker study was conducted by simultaneously performing immunohistochemistry and next-generation sequencing (NGS) with tumor and blood samples.ResultsComplete response was confirmed in 7/32 patients (21.8%), 2 of whom received radical surgery with pathologic-confirmed complete response. Fifteen partial responses (46.8%) were observed, resulting in a 68.6% overall response rate. NGS of the 16 tumor specimens demonstrated that the most common co-occurring copy number alteration was CCNE1 amplification, which was present in 40% of HER2+ tumors. The relationship between CCNE1 amplification and lack of response to HER2-targeted therapy trended toward statistical significance (66.7% of non-responders versus 22.2% of responders harbored CCNE1 amplification; P = 0.08). Patients with high level ERBB2 amplification by NGS were more likely to respond to therapy, compared with patients with low level ERBB2 amplification (P = 0.02). Analysis of cfDNA showed that detectable ERBB2 copy number amplification in plasma was predictive to the response (100%, response rate) and changes in plasma-detected genomic alterations were associated with lapatinib sensitivity and/or resistance. The follow-up cfDNA genomics at disease progression demonstrated that there are emergences of other genomic aberrations such as MYC, EGFR, FGFR2 and MET amplifications.ConclusionsThe present study showed that HER2+ GC patients respond differently according to concomitant genomic aberrations beyond ERBB2, high ERBB2 amplification by NGS or cfDNA can be a positive predictor for patient selection, and tumor genomic alterations change significantly during targeted agent therapy.     

De-escalated therapy for HR+/HER2+ breast cancer patients with Ki67 response after 2-week letrozole: results of the PerELISA neoadjuvant study

BackgroundIn human epidermal growth factor receptor 2 (HER2+) breast cancers, neoadjuvant trials of chemotherapy plus anti-HER2 treatment consistently showed lower pathologic complete response (pCR) rates in hormone receptor (HR) positive versus negative tumors. The PerELISA study was aimed to evaluate the efficacy of a de-escalated, chemotherapy-free neoadjuvant regimen in HR+/HER2+ breast cancer patients selected on the basis of Ki67 inhibition after 2-week letrozole.Patients and methodsPerELISA is a phase II, multicentric study for postmenopausal patients with HR+/HER2+ operable breast cancer. Patients received 2-week letrozole, and then underwent re-biopsy for Ki67 evaluation. Patients classified as molecular responders (Ki67 relative reduction >20% from baseline) continued letrozole and started trastuzumab-pertuzumab for five cycles. Patients classified as molecular non-responders started weekly paclitaxel for 13 weeks combined with trastuzumab-pertuzumab. Primary aim was breast and axillary pCR. According to a two-stage Simon’s design, to reject the null hypothesis, at least 8/43 pCR had to be documented.ResultsSixty-four patients were enrolled, 44 were classified as molecular responders. All these patients completed the assigned treatment with letrozole-trastuzumab-pertuzumab and underwent surgery. A pCR was observed in 9/44 cases (20.5%, 95% confidence interval 11.1% to 34.5%). Among molecular non-responders, 16/17 completed treatment and underwent surgery, with pCR observed in 81.3% of the cases. PAM50 intrinsic subtype was significantly associated with Ki67 response and pCR. Among molecular responders, the pCR rate was significantly higher in HER2-enriched than in other subtypes (45.5% versus 13.8%, P = 0.042).ConclusionsThe primary end point of the study was met, by reaching the pre-specified pCRs. In patients selected using Ki67 reduction after short-term letrozole exposure, a meaningful pCR rate can be achieved without chemotherapy. PAM50 intrinsic subtyping further refines our ability to identify a subset of patients for whom chemotherapy might be spared.EUDRACT number2013-002662-40ClinicalTrials.gov IdentifierNCT02411344     

De-escalation strategies in HER2-positive early breast cancer (EBC): final analysis of the WSG-ADAPT HER2+/HR− phase II trial: efficacy,safety, and predictive markers for 12 weeks of neoadjuvant dual blockade with trastuzumab and pertuzumab ± weekly paclitaxel

BackgroundResponse rates in HER2-overexpressing EBC treated with neoadjuvant chemotherapy and trastuzumab (T) have been improved by addition of pertuzumab (P). The prospective, phase II, neoadjuvant WSG-ADAPT HER2+/HR− trial assessed whether patients with strong early response to dual blockade alone might achieve pathological complete response (pCR) comparable to that of patients receiving dual blockade and chemotherapy.Patients and methodsFemale patients with HER2+/HR− EBC (M0) were randomized (5:2) to 12 weeks of T + P ± weekly paclitaxel (pac) at 80 mg/m². Early response was defined as proliferation decrease ≥30% of Ki-67 (versus baseline) or low cellularity (<500 invasive tumor cells) in the 3-week biopsy. The trial was designed to test non-inferiority for pCR in early responding patients of the T + P arm versus all chemotherapy-treated patients.ResultsFrom February 2014 to December 2015, 160 patients were screened, 92 were randomized to T + P and 42 to T + P+pac. Baseline characteristics were well balanced (median age 54 versus 51.5 years, cT2 51.1 versus 52.4%, cN0 54.3 versus 61.9%); 91.3% of patients completed T + P per protocol and 92.9% T + P+pac. The pCR rate in the T + P+pac arm was 90.5%, compared with 36.3% in the T + P arm as a whole. In the T + P arm, 24/92 were classified as non-responders, and their pCR rate was only 8.3% compared with 44.7% in responders (38/92) and 42.9% in patients with unclassified early response (30/92). No new safety signals were observed in the study population.ConclusionAddition of taxane monotherapy to dual HER2 blockade in a 12-week neoadjuvant setting substantially increases pCR rates in HER2+/HR− EBC compared with dual blockade alone, even within early responders to dual blockade. Early non-response under dual blockade strongly predicts failure to achieve pCR.     

Quantitative proteomic analysis of HER2 expression in the selection of gastric cancer patients for trastuzumab treatment

BackgroundA wide range of response rates have been reported in HER2-positive gastric cancer (GC) patients treated with trastuzumab. Other HER2-targeted therapies for GC have yet to show efficacy in clinical trials. These findings raise question about the ability of standard HER2 diagnostics to accurately distinguish between GC patients who would and would not benefit from anti-HER2 therapies.Patients and methodsGC patients (n = 237), including a subset from the Trastuzumab in GC (ToGA) trial were divided into three groups based on HER2 status and history of treatment with standard chemotherapy or chemotherapy plus trastuzumab. We applied mass spectrometry-based proteomic analysis to quantify HER2 protein expression in formalin-fixed tumor samples. Using HER2 expression as a continuous variable, we defined a predictive protein level cutoff to identify which patients would benefit from trastuzumab. We compared quantitated protein level with clinical outcome and HER2 status as determined by conventional HER2 diagnostics.ResultsQuantitative proteomics detected a 115-fold range of HER2 protein expression among patients diagnosed as HER2 positive by standard methods. A protein level of 1825 amol/µg was predicted to determine benefit from the addition of trastuzumab to chemotherapy. Trastuzumab treated patients with HER2 protein levels above this cutoff had twice the median overall survival (OS) of their counterparts below the cutoff (35.0 versus 17.5 months, P = 0.011). Conversely, trastuzumab-treated patients with HER2 levels below the cutoff had outcomes similar to HER2-positive patients treated with chemotherapy. (Progression-free survival = 7.0 versus 6.5 months: P = 0.504; OS = 17.5 versus 12.6 months: P = 0.520). HER2 levels were not prognostic for response to chemotherapy.ConclusionsProteomic analysis of HER2 expression demonstrated a quantitative cutoff that improves selection of GC patients for trastuzumab as compared with current diagnostic methods.     

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)

BackgroundWe 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.MethodsPatients 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/m²) with or without everolimus (5 mg p.o. daily, after a step-wise dose–escalation starting from 2.5 mg 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.FindingsOf 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.InterpretationNeoadjuvant 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.FundingNovartis, Roche, and Sanofi-Aventis.     

Circulating tumour cells and pathological complete response: independent prognostic factors in inflammatory breast cancer in a pooled analysis of two multicentre phase II trials (BEVERLY-1 and -2) of neoadjuvant chemotherapy combined with bevacizumab

BackgroundWe present a pooled analysis of predictive and prognostic values of circulating tumour cells (CTC) and circulating endothelial cells (CEC) in two prospective trials of patients with inflammatory breast cancer (IBC) treated with neoadjuvant chemotherapy combined with neoadjuvant and adjuvant bevacizumab.Patients and methodsNonmetastatic T4d patients were enrolled in two phase II multicentre trials, evaluating bevacizumab in combination with sequential neoadjuvant chemotherapy of four cycles of FEC followed by four cycles of docetaxel in HER2-negative tumour (BEVERLY-1) or docetaxel and trastuzumab in HER2-positive tumour (BEVERLY-2). CTC and CEC were detected in 7.5 and 4 ml of blood, respectively, with the CellSearch System.ResultsFrom October 2008 to September 2010, 152 patients were included and 137 were evaluable for CTC and CEC. At baseline, 55 patients had detectable CTC (39%). After four cycles of chemotherapy, a dramatic drop in CTC to a rate of 9% was observed (P < 0.01). Pathological complete response (pCR) rate was 40%. No correlation was found between CTC or CEC levels and pCR rate. Median follow-up was 43 months. CTC detection (≥1 CTC/7.5 ml) at baseline was associated with shorter 3-year disease-free survival (39% versus 70% for patients without CTC, P < 0.01, HR 2.80) and shorter 3-year overall survival (OS) (P < 0.01). In multivariate analysis, independent prognostic parameters for shorter survival were absence of hormonal receptors, no pCR and CTC detection at baseline. CEC level at baseline or variations during treatment had no prognostic value.ConclusionIn this pooled analysis of two prospective trials in nonmetastatic IBC, detection rate of CTC was 39% with a strong and independent prognostic value for survival. Combination of pCR after neoadjuvant treatment with no CTC detection at baseline isolated a subgroup of IBC with excellent OS (94% 3-year OS), suggesting that CTC count could be part of IBC stratification in prospective trials.     

Pathway level alterations rather than mutations in single genes predict response to HER2-targeted therapies in the neo-ALTTO trial

BackgroundWe performed whole-exome sequencing of pretreatment biopsies and examined whether genome-wide metrics of overall mutational load, clonal heterogeneity or alterations at variant, gene, and pathway levels are associated with treatment response and survival.Patients and methodsTwo hundred and three biopsies from the NeoALTTO trial were analyzed. Mutations were called with MuTect, and Strelka, using pooled normal DNA. Associations between DNA alterations and outcome were evaluated by logistic and Cox-proportional hazards regression.ResultsThere were no recurrent single gene mutations significantly associated with pathologic complete response (pCR), except PIK3CA [odds ratio (OR) = 0.42, P = 0.0185]. Mutations in 33 of 714 pathways were significantly associated with response, but different genes were affected in different individuals. PIK3CA was present in 23 of these pathways defining a ‘trastuzumab resistance-network’ of 459 genes. Cases with mutations in this network had low pCR rates to trastuzumab (2/50, 4%) compared with cases with no mutations (9/16, 56%), OR = 0.035; P < 0.001. Mutations in the ‘Regulation of RhoA activity’ pathway were associated with higher pCR rate to lapatinib (OR = 14.8, adjusted P = 0.001), lapatinib + trastuzumab (OR = 3.0, adjusted P = 0.09), and all arms combined (OR = 3.77, adjusted P = 0.02). Patients (n = 124) with mutations in the trastuzumab resistance network but intact RhoA pathway had 2% (1/41) pCR rate with trastuzumab alone (OR = 0.026, P = 0.001) but adding lapatinib increased pCR rate to 45% (17/38, OR = 1.68, P = 0.3). Patients (n = 46) who had no mutations in either gene set had 6% pCR rate (1/15) with lapatinib, but had the highest pCR rate, 52% (8/15) with trastuzumab alone.ConclusionsMutations in the RhoA pathway are associated with pCR to lapatinib and mutations in a PIK3CA-related network are associated with resistance to trastuzumab. The combined mutation status of these two pathways could define patients with very low response rate to trastuzumab alone that can be augmented by adding lapatinib or substituting trastuzumab with lapatinib.     

p53 status and efficacy of primary anthracyclines/alkylating agent-based regimen according to breast cancer molecular classes

BackgroundWe hypothesized that, among molecular subclasses of breast cancer, p53 status may have a differential predictive value for the efficacy of anthracyclines/alkylating agents-based regimen. We analysed the efficacy of a preoperative combination between 5-fluorouracil, anthracyclines and cyclophosphamide according to both p53 status and molecular classification.Patients and methodsOestrogen receptor (ER), progesterone receptor (PgR), human epidermal growth factor receptor 2 (HER2) expression and p53 status were determined by immunohistochemistry in 293 samples from two different centres. A logistic regression model was used for multivariate analysis of predictors for pathological complete response (pCR).Resultsp53 immunostaining (54%) was associated with high grade (P = 0.002) and ER negativity (P = 0.04). p53 was detected in 59% of triple-negative tumours (ER-/PgR-/HER2-, n = 120 patients). In the overall population, pCR (9.6%) was independently predicted by high tumour grade (P = 0.002) and ER/PgR/HER2 triple negativity (P = 0.0004), but not by p53 status (P = 0.12). p53 immunostaining was associated with a trend for a higher rate of pCR in triple-negative tumours [relative risk (RR) = 2.5, 95% confidence interval (CI) = 0.8–7.5, P = 0.09], but not in non-triple-negative tumours (RR = 0.73, 95% CI = 0.16–3.3, P = 0.69).Conclusionp53 status may have a different predictive value for efficacy of anthracycline/alkylating agents-based regimen in each molecular subclass, a result which may explain the different results reported in literature.     

Open-label randomized clinical trial of standard neoadjuvant chemotherapy with paclitaxel followed by FEC versus the combination of paclitaxel and everolimus followed by FEC in women with triple receptor-negative breast cancer

BackgroundEverolimus synergistically enhances taxane-induced cytotoxicity in breast cancer cells in vitro and in vivo in addition to demonstrating a direct antiproliferative activity. We aim to determine pharmacodynamics changes and response of adding everolimus to standard neoadjuvant chemotherapy in triple-negative breast cancer (TNBC).Patients and methodsPhase II study in patients with primary TNBC randomized to T-FEC (paclitaxel 80 mg/m² i.v. weekly for 12 weeks, followed by 5-fluorouracil 500 mg/m², epirubicin 100 mg/m², and cyclophosphamide 500 mg/m² every 3 weeks for four cycles) versus TR-FEC (paclitaxel 80 mg/m² i.v. and everolimus 30 mg PO weekly for 12 weeks, followed by FEC). Tumor samples were collected to assess molecular changes in the PI3K/AKT/mTOR pathway, at baseline, 48 h, 12 weeks, and at surgery by reverse phase protein arrays (RPPA). Clinical end points included 12-week clinical response rate (12-week RR), pathological complete response (pCR), and toxicity.ResultsSixty-two patients were registered, and 50 were randomized, 27 received T-FEC, and 23 received TR-FEC. Median age was 48 (range 31–75). There was downregulation of the mTOR pathway at 48 h in the TR-FEC arm. Twelve-week RR by ultrasound were 29.6% versus 47.8%, (P = 0.075), and pCR were 25.9% versus 30.4% (P = 0.76) for T-FEC and TR-FEC, respectively. mTOR downregulation at 48 h did not correlate with 12-week RR in the TR-FEC group (P = 0.58). Main NCI grade 3/4 toxicities included anemia, neutropenia, rash/desquamation, and vomiting in both arms. There was one case of grade 3 pneumonitis in the TR-FEC arm. No grade 3/4 stomatitis occurred.ConclusionThe addition of everolimus to paclitaxel was well tolerated. Everolimus downregulated mTOR signaling but downregulation of mTOR at 48 h did not correlate with 12-week RR in the TR-FEC group.Clinical trial numberNCT00499603.     

FAIRLANE,a double-blind placebo-controlled randomized phase II trial of neoadjuvant ipatasertib plus paclitaxel for early triple-negative breast cancer

BackgroundThis hypothesis-generating trial evaluated neoadjuvant ipatasertib–paclitaxel for early triple-negative breast cancer (TNBC).Patients and methodsIn this randomized phase II trial, patients with early TNBC (T ≥ 1.5 cm, N0–2) were randomized 1 : 1 to receive weekly paclitaxel 80 mg/m² with ipatasertib 400 mg or placebo (days 1–21 every 28 days) for 12 weeks before surgery. Co-primary end points were pathologic complete response (pCR) rate (ypT0/TisN0) in the intention-to-treat (ITT) and immunohistochemistry phosphatase and tensin homolog (PTEN)-low populations. Secondary end points included pCR rate in patients with PIK3CA/AKT1/PTEN-altered tumors and pre-surgery response rates by magnetic resonance imaging (MRI).ResultspCR rates with ipatasertib versus placebo were 17% versus 13%, respectively, in the ITT population (N = 151), 16% versus 13% in the immunohistochemistry PTEN-low population (N = 35), and 18% versus 12% in the PIK3CA/AKT1/PTEN-altered subgroup (N = 62). Rates of overall and complete response (CR) by MRI favored ipatasertib in all three populations (CR rate 39% versus 9% in the PIK3CA/AKT1/PTEN-altered subgroup). Ipatasertib was associated with more grade ≥3 adverse events (32% versus 16% with placebo), especially diarrhea (17% versus 1%). Higher cycle 1 day 8 (C1D8) immune score was significantly associated with better response only in placebo-treated patients. All ipatasertib-treated patients with low immune scores and a CR had PIK3CA/AKT1/PTEN-altered tumors.ConclusionsAdding ipatasertib to 12 weeks of paclitaxel for early TNBC did not clinically or statistically significantly increase pCR rate, although overall response rate by MRI was numerically higher with ipatasertib. The antitumor effect of ipatasertib was most pronounced in biomarker-selected patients. Safety was consistent with prior experience of ipatasertib–paclitaxel. A T-cell-rich environment at C1D8 had a stronger association with improved outcomes in paclitaxel-treated patients than seen for baseline tumor-infiltrating lymphocytes. This dependency may be overcome with the addition of AKT inhibition, especially in patients with PIK3CA/AKT1/PTEN-altered tumors.ClinicalTrials.govNCT02301988.     

Low-scale phosphoproteome analyses identify the mTOR effector p70 S6 kinase 1 as a specific biomarker of the dual-HER1/HER2 tyrosine kinase inhibitor lapatinib (Tykerb®) in human breast carcinoma cells

BackgroundDiscovery of key proliferative and/or survival cascades closely linked to the biological effects of human epidermal growth factor receptor (HER) 1 (erbB-1) and/or HER2 (erbB-2) inhibitors may identify a priori mechanisms responsible for the development of acquired resistance in breast cancer disease. Here, we took advantage of a semiquantitative protein array technology to identify intracellular oncogenic kinases that distinctively correlate with breast cancer cell sensitivity/resistance to the dual-HER1/HER2 tyrosine kinase inhibitor lapatinib (Tykerb®).Materials and methodsMCF-7 cells were forced to overexpress HER2 following stable transduction with pBABE-HER2 retroviruses. The Human Phospho-MAPK Array Proteome Profiler™ (R&D Systems) was used to molecularly assess the effects of both the mono-HER2 inhibitor trastuzumab (Herceptin™) and the dual-HER1/HER2 inhibitor lapatinib on 21 different oncogenic kinases. A model of acquired resistance to lapatinib (MCF-7/HER2-Lap10 cells) was established by chronically exposing MCF-7/HER2 cells to increasing concentrations of lapatinib for >10 months.ResultsTreatment of MCF-7/HER2 cells with either trastuzumab or lapatinib similarly impaired HER2-enhanced activation status (i.e. phosphorylation) of the mitogen-activated protein kinases, c-Jun N-terminal kinases 1–3 and p38α/β/γ/δ and of the serine/threonine kinases AKT, glycogen synthase kinase-3, p90 ribosomal s6 kinase1/2, and mitogen- and stress-activated protein kinase1/2. Trastuzumab was less effective than lapatinib at blocking extracellular-signal regulated kinase (ERK) 1/2 and, notably, it failed to deactivate the mammalian target of rapamycin (mTOR) effector p70S6K1. Conversely, lapatinib treatment caused a drastic decrease in the phosphorylation of p70S6K1 at ERK1/2-regulated sites (Thr⁴²¹/Ser⁴²⁴) and, as a consequence, p70S6K1 activity measured by its phospho-Thr³⁸⁹ levels was abolished. The mTOR inhibitor rapamycin was found to supraadditively increase lapatinib efficacy in MCF-7/HER2 cells [∼10-fold enhancement; combination index (CI₅₀) = 0.243 < 1.0 = additivity, P < 0.001] but not in p70S6K1 gene-amplified MCF-7 parental cells (∼1.3-fold enhancement; CI₅₀ = 0.920 ≅ 1.0 = additivity). Lapatinib-resistant MCF-7/HER2-Lap10 cells, which are capable of growing in the continuous presence of 10 μm lapatinib without significant effects on cell viability, notably exhibited a lapatinib-insensitive hyperphosphorylation of p70S6K1. Rapamycin cotreatment suppressed p70S6K1 hyperactivation and synergistically resensitized MCF-7/HER2-Lap10 cells to lapatinib (>20-fold increase in lapatinib-induced cytotoxicity; CI₅₀ = 0.175 < 1.0 = additivity).ConclusionsSerine–threonine kinase p70S6K1, a marker for mTOR activity that regulates protein translation, constitutes a specific biomarker for the biological effects of the dual-HER1/HER2 inhibitor lapatinib. The clinical implications of our data are that the efficacy of lapatinib might be enhanced with therapies that target the mTOR pathway. Rapamycin analogues such as CCI-779 (Temsirolimus) and RAD001 (Everolimus) may warrant further clinical evaluation to effectively delay or prevent the development of acquired resistance to lapatinib in HER2-positive breast cancer patients.     

A phase II study of lapatinib monotherapy in chemotherapy-refractory HER2-positive and HER2-negative advanced or metastatic breast cancer

BackgroundThe efficacy and tolerability of the epidermal growth factor receptor/human epidermal growth factor receptor type 2 (HER2) tyrosine kinase inhibitor lapatinib in refractory metastatic breast cancer were assessed.Patients and methodsIn a phase II, open-label study, patients with previously treated HER2-positive (n = 140) or HER2-negative (n = 89) metastatic breast cancer received once-daily oral lapatinib 1500 mg/day.ResultsMost (76%) patients had received four or more lines of prior therapy. The response rate in the HER2-positive cohort was 4.3% by investigator assessment and 1.4% by independent assessment. Both assessments established that ∼6% of HER2-positive patients derived clinical benefit from lapatinib, being progression free for ≥6 months. No objective tumor responses occurred in the HER2-negative cohort. Independent review assessments of median time to progression and median progression-free survival were similar in the HER2-positive and HER2-negative cohorts (9.1 and 7.6 weeks, respectively). All responders exhibited HER2 overexpression (3+ by immunohistochemistry), and five of six responders were HER2 amplified by FISH. Lapatinib-related adverse events, including diarrhea (54%), rash (30%), and nausea (24%), were primarily mild to moderate in severity.ConclusionsLapatinib monotherapy had modest clinical activity in HER2-positive metastatic breast cancer that progressed on prior trastuzumab regimens. No apparent clinical activity was observed in chemotherapy-refractory, HER2-negative disease.     

Multicenter phase II study of trastuzumab in combination with capecitabine and oxaliplatin for advanced gastric cancer

BackgroundTrastuzumab has been approved for use in combination with fluoropyrimidine plus cisplatin for the treatment of human epidermal growth factor receptor 2 (HER2)-positive advanced gastric cancer (AGC). Although capecitabine plus oxaliplatin (XELOX) is a standard first-line regimen for AGC, combination trastuzumab plus XELOX has not been studied.MethodsPatients with metastatic or unresectable HER2-positive AGC were diagnosed by either HER2 immunohistochemistry (IHC) 3+ or IHC 2+/fluorescence in-situ hybridisation (FISH)+ received intravenous trastuzumab (8 mg/kg for first cycle and 6 mg/kg for subsequent cycles on day 1) plus oral capecitabine (1000 mg/m² twice daily on days 1–14) and intravenous oxaliplatin (130 mg/m² on day 1), every 3 weeks. The primary end-point was the objective response rate, and secondary end-points included progression-free survival (PFS), overall survival (OS) and toxicity profiles.ResultsFifty-five HER2-positive AGC patients were enrolled between August 2011 and February 2013. The median age was 57 years (range = 29–74). The confirmed objective response rate was 67% (95% confidence interval (CI) = 54–80%). After a median follow-up period of 13.8 months (range = 6.1–23.9), the median PFS and OS were 9.8 months (95% CI = 7.0–12.6) and 21.0 months (95% CI = 6.4–35.7), respectively. Frequently encountered grade 3–4 toxicities included neutropenia (18%), anaemia (11%), and peripheral neuropathy (11%). There was a treatment-related death caused by severe diarrhoea and complicated sepsis.ConclusionCombination of trastuzumab and XELOX is well tolerated and highly effective in patients with HER2-positive AGC.     

PREPARE trial: a randomized phase III trial comparing preoperative,dose-dense,dose-intensified chemotherapy with epirubicin,paclitaxel and CMF versus a standard-dosed epirubicin/cyclophosphamide followed by paclitaxel ± darbepoetin alfa in primary breast cancer—results at the time of surgery

BackgroundPreoperative chemotherapy is a recommended treatment of both primary operable and locally advanced breast cancer. Strategies to improve efficacy include the use of anthracyclines, taxanes, and intensified dose with bone marrow support.Patients and methodsPatients received neoadjuvant epirubicin 90 mg/m² plus cyclophosphamide 600 mg/m² followed by paclitaxel 175 mg/m² (EC→T), each 3-weekly for four cycles (n = 370), or epirubicin 150 mg/m² followed by paclitaxel 225 mg/m² with pegfilgrastim followed by CMF (cyclophosphamide 500 mg/m², methotrexate 40 mg/m², fluorouracil 600 mg/m²) on days 1 and 8 (E_dd→T_dd→CMF), each 2-weekly and for three cycles (n = 363). Patients were randomly allocated to either simultaneous darbepoetin alfa (DA) (n = 356) or none (n = 377).ResultsPathological complete response (pCR) rate (breast) was higher with E_dd→T_dd→CMF, 18.7% versus 13.2% with EC→T; P = 0.043, ypT0/Tis; ypN0 was reported in 20.9% versus 14.3% respectively; P = 0.019. Patients with grade 3 tumors and negative hormone receptor status had a significantly higher pCR rate. Mean hemoglobin values maintained higher with DA (13.6 versus 12.6 g/dl). E_dd→T_dd→CMF regimen showed more grade 3–4 mucositis, sensory neuropathy, and neurological complaints. Thromboembolic events were more frequent on DA (3% versus 6%; P = 0.055).ConclusionDose-dense and -intensified neoadjuvant chemotherapy with E_dd→T_dd→CMF was potentially superior to EC→T in terms of pCR. Primary use of DA did not affect pCR.     

Insulin-like growth factor type 1 receptor (IGF-1R) exclusive nuclear staining: A predictive biomarker for IGF-1R monoclonal antibody (Ab) therapy in sarcomas

AimsA minority of patients with advanced sarcoma achieve prolonged progression free survival (PFS) with insulin growth factor type 1 receptor (IGF-1R) monoclonal antibody (Ab) therapy. A biomarker identifying those patients beforehand would be useful to select patients for the development of these agents.MethodsThis single centre series includes patients with unresectable or metastatic soft tissue sarcomas (STS), Ewing sarcoma (ES) and osteosarcoma treated with IGF-1R Ab (R1507, IMC-A12, SCH 717454 and CP-751.871) in the Centre Léon Bérard. Tumour samples were analysed by immunohistochemistry for expression of IGF-1R, insulin-like growth factor binding protein type 3 (IGFBP-3), Ki67, epidermal growth factor receptor (HER1) and human epidermal growth factor receptor 2 (HER2). Predictive factors for PFS and overall survival (OS) were investigated.ResultsAll tumour samples had a positive IGF-1R immunostaining on 60% to 100% of tumour cells. IGFBP-3 immunostaining was observed in 12 (75%) samples with 5% to 100% of positive cells. IGF-1R immunostaining was nuclear (n = 9, 56%), cytoplasmic (n = 4, 25%), or nuclear + cytoplasmic (n = 3, 19%). Neither IGFBP-3 expression, nor Ki67 was correlated to PFS. HER2 and HER1 staining were positive in 0 and 2 samples respectively (both primary resistant to IGF-1R Ab therapy). Exclusive intra-nuclear immunoreactivity for IGF-1R was significantly associated with a better PFS (p = 0.01) and OS (p = 0.007).ConclusionExclusive nuclear localisation of IGF-1R is an easily testable biomarker associated with a better PFS and OS for patients treated with IGF-1R Ab therapy. Nuclear localisation of IGF-1R in tumour cells might be a hallmark of pathway activation.