Abstract P6-07-15: The effect of taxanes in ER+ early breast cancer is likely to be mitigated by chromosomal instability

Background: Mechanisms of tumour sensitivity to microtubule-stabilizing (MTS) agents, such as taxanes, are still a matter of debate. Through an RNA interference screen for regulators of taxane resistance, our group identified a number of genes which initiated taxane resistance and Chromosomal INstability (CIN) (1) when silenced, suggesting that the cellular mechanisms that monitor faithful chromosome segregation may also impact upon taxane sensitivity. Consistent with this hypothesis, we previously reported in a small clinical trial cohort of ovarian cancers that CIN tumours (defined by overexpression of the CIN70 signature) appeared to be relatively resistant to paclitaxel in vivo (2). We have observed that repression of a subset of the CIN70 signature occurs in diploid cancer cells following paclitaxel exposure, contributing to cell death. Conversely, less efficient repression of these CIN70 genes occurs in CIN cells following paclitaxel exposure. Overexpression of the CIN70 signature is associated with poor clinical outcome and chromosomal instability is significantly correlated with high tumour grade in ER positive disease. We hypothesised that in ER+ tumours the effect of taxanes should decrease with tumour grade and relative chromosomal instability (3). We assessed this hypothesis by analysing the differences in the published taxane effect in the EBCTCG Chemotherapy overview (4) according to tumour grade.

Methods: Annual event rate ratios and 95% CIs were calculated from data on over 20,000 early breast cancer patients treated with chemotherapy (4). P-values for trend in taxane effect were calculated across 3 tumour grade categories or for heterogeneity between 2 categories.

Results: The table shows annual event rate ratios (CIs) for grade categories, for taxane-plus-anthracycline-based regimen versus the same, or more (< doubled or ∼doubled) non-taxane cytotoxic chemotherapy. Significantly different taxane effects were observed across categories of tumour grade. For both endpoints taxane benefit increased with lower tumour grade, there was a smaller effect in high grade tumours and no evidence the treatment benefit decreased with follow up time.

Abstract PD07-07: Prediction of antiproliferative response to lapatinib by HER3 in an exploratory analysis of HER2-non-amplified (HER2−) breast cancer in the MAPLE presurgical study (CRUK E/06/039)

Aim: To identify pretreatment biomarker predictors of Ki67 response to lapatinib in women with HER2− primary breast cancer.

Background: Lapatinib is an EGFR/HER2 inhibitor. Its clinical use is restricted to HER2 overexpressing disease. The MAPLE (Molecular Antiproliferative Predictors of Lapatinib's Effects) presurgical window of opportunity study of lapatinib vs placebo was conducted in women with HER2-amplified (HER2+) or HER2− primary disease. Ki67 (primary end-point) was reduced by a geomean 46% (95%CI 23–63%, p = 0.002) and 27% (95%CI 8–42%, p = 0.008) in HER2+ and HER2− disease, respectively (Leary et al, AACR 2012). We have now assessed whether predictive biomarkers of the antiproliferative response in HER2− disease could be identified.

Methods: 121 primary breast cancer patients were randomized (3:1) to 14 days of 1500mg/d lapatinib or placebo before surgery. Biopsies were taken before treatment and at surgery. Ki67 responders were defined as having a >/=50% reduction in Ki67 compared to baseline (Ellis, P et al, Breast Cancer Res Treat 1998, 48, 107). ER, PgR, HER2, EGFR, pAKT, pERK1/2 (nuclear and cytoplasmic), stathmin and apoptosis (TUNEL) were assessed by IHC (+FISH for HER2[all cases]) and scored visually by continuous methods. HER2, HER3, epiregulin (epir), amphiregulin (amphir) and neuregulin (neur) were assessed by qrtPCR.

Results: Three of the 121 patients were excluded because of inadequate biopsy material. Ninety-one of the remaining 118 patients received lapatinib: 7/19 (37%) HER2+ cases and 10/72 (14%) HER2− cases were Ki67 responders. Thus while the proportion of Ki67 responders was higher for HER2+ disease there was a similar or higher absolute number of responders with HER2− disease. All of the following relates to patients with HER2− disease. None of the pretreatment levels of ER, PgR, pAKT, pERK1/2, EGFR, epir, amphir or neur were associated with Ki67 response (p > 0.20). However, HER3 (p = 0.01) and HER2 (p = 0.06) mRNA levels were associated with greater Ki67 response. There was a tendency for Ki67 response to be greater with lower baseline Ki67 (p = 0.07). Multivariate analysis showed only HER3 mRNA levels to be independently significant. HER2 and HER3 mRNA levels were highly correlated (rho = 0.67, p < 0.001), a relationship confirmed in 2 other datasets (Wang et al, Breast Cancer Res, 2011, 13, R92; Dunbier et al, submitted). All Ki67 responders were above the median for both HER3 and HER2 expression.

Conclusions: Lapatinib is antiproliferative in a subgroup of HER2− tumours. This exploratory analysis indicates that they are characterized by high HER3 expression. The possible importance of high HER2:HER3 heterodimers in predicting this response is supported by the relationship between HER2 and HER3 expression. Further exploration of lapatinib is merited in HER2− cases with high HER3 expression.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr PD07-07.

Abstract OT1-1-04: ALTERNATIVE: safety and efficacy of lapatinib (L), trastuzumab (T), or both in combination with an aromatase inhibitor (AI) for the treatment of hormone receptor-positive (HR+), human epidermal growth factor receptor 2 positive (HER2+) metastatic breast cancer

Background: Overexpression of the human epidermal growth factor receptor 2 (HER2) gene in breast cancer is associated with an aggressive phenotype, poor prognosis, and resistance to endocrine therapies. Of HER2+ patients, ∼50% are also hormone receptor-positive (HR+). For patients who are both HER2+ and HR+, combining the AI letrozole with the dual tyrosine kinase inhibitor L has been shown to improve outcomes compared with letrozole alone. The combination of L and T, a humanized monoclonal antibody-targeting HER2, has been shown to improve outcomes compared with L alone.

Trial design: The ALTERNATIVE study is a Phase III, randomized, open-label, multicenter trial, which will examine the efficacy of L/T/AI in combination versus T/AI alone. Patients will be randomized to 1 of 3 treatment arms: L 1000 mg po QD plus T (loading dose of 8 mg/kg followed by maintenance with 6 mg/kg IV q3w plus an AI po QD); T plus an AI; or L 1500 mg po QD plus an AI. Choices of AI include letrozole, anastrozole, or exemestane.

Eligibility criteria: Postmenopausal female patients with HER2+/HR+ metastatic breast cancer (MBC) who have received neo/adjuvant T and endocrine therapy, are treatment naïve for MBC, and are not candidates for chemotherapy.

Specific aims: The primary efficacy endpoint is overall survival (OS), defined as the time from randomization until death due to any cause, for L/T/AI compared with T/AI alone. Secondary efficacy objectives include comparisons of OS between T/AI and L/AI as well as between T/L/AI and L/AI in addition to comparisons of progression-free survival, overall response rate, time to response, and duration of response. The safety objective is to evaluate the safety and tolerability for all 3 treatment groups.

A 4-year recruitment is anticipated. More than 200 centers across 37 countries are planned; approximately 110 centers are currently open for enrollment.

Statistical methods: The study is powered to detect a 42% reduction in risk of death (hazard ratio=0.70) in patients who receive L/T/AI (median 28.5 months) versus T/AI (median 20 months) using a 1-sided test for superiority with α=0.025. The required number of total events to achieve a power of 80% is 249. Secondary comparisons are not powered and will be based on the intent-to-treat population.

Present and target accrual: Twenty-six (26) of 525 patients have been randomized. Patients who have participated in previous neo-/adjuvant trials including a T regimen are eligible, provided they meet all other inclusion criteria.

The study is currently recruiting patients, with an anticipated target accrual of 525 patients by March 2016.

Clinical trial registry number: NCT01160211

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr OT1-1-04.

Competition between antiferromagnetic and charge-density-wave order in the half-filled Hubbard-Holstein model

We present a determinant quantum Monte Carlo study of the competition between instantaneous on-site Coulomb repulsion and retarded phonon-mediated attraction between electrons, as described by the two-dimensional Hubbard-Holstein model. At half filling, we find a strong competition between antiferromagnetism (AFM) and charge-density-wave (CDW) order. We demonstrate that a simple picture of AFM-CDW competition that incorporates the phonon-mediated attraction into an effective-U Hubbard model requires significant refinement. Specifically, retardation effects slow the onset of charge order so that CDW order remains absent even when the effective U is negative. This delay opens a window where neither AFM nor CDW order is well established and where there are signatures of a possible metallic phase.

Comparative persistence and adherence to overactive bladder medications in patients with and without diabetes

AIMS

This retrospective administrative claims-based study evaluated comparative persistence and adherence to overactive bladder (OAB) medications in US patients with and without diabetes.

METHODS

Patients ≥ 18 years who initiated OAB medications between 1 January 2005 and 30 June 2008 were analysed from the Truven Health MarketScan Commercial and Medicare Supplemental databases. A 12-month baseline period prior to OAB medication initiation was used to classify patients into diabetes and non-diabetes cohorts, and measure demographic and clinical characteristics. Patients in each cohort were directly matched 1 : 1 based on index year, age, gender and geographic region. Multiple logistic regression was used to compare cohorts on outcomes of ≥ 80% adherence to OAB medications and refilling a second OAB medication prescription. Cox's proportional hazards model compared time to non-persistence with OAB medications between both cohorts.

RESULTS

In total, 36,560 patients were included in each cohort. Compared with the non-diabetes cohort, the diabetes cohort had 21.5% higher odds of ≥ 80% adherence to OAB medications, 16.6% higher odds of filling a second OAB medication prescription and 10.3% lower hazard of non-persistence with OAB medications during a 12-month evaluation period.

CONCLUSIONS

Patients with diabetes were more persistent and adherent to OAB medications and had higher odds of filling a second medication prescription than patients without diabetes. Further research is needed to identify factors responsible for these findings.

Surface adatom conductance filtering in scanning tunneling spectroscopy of co-doped BaFe2As2 iron pnictide superconductors

We establish in a combination of ab initio theory and experiments that the tunneling process in scanning tunneling microscopy or spectroscopy on the A-122 iron pnictide superconductors-in this case BaFe(2-x)Co(x)As(2)-involves a strong adatom filtering of the differential conductance from the near-E(F) Fe-3d states, which in turn originates from the topmost subsurface Fe layer of the crystal. The calculations show that the dominance of surface Ba-related tunneling pathways leaves fingerprints found in the experimental differential conductance data, including large particle-hole asymmetry and energy-dependent contrast inversion in conductance maps.

Ca(2)Y(2)Cu(5)O(10): the first frustrated quasi-1D ferromagnet close to criticality

Ca(2)Y(2)Cu(5)O(10) is built up from edge-shared CuO(4) plaquettes forming spin chains. From inelastic neutron scattering data we extract an in-chain nearest-neighbor exchange J(1)≈-170  K and the frustrating next-neighbor J(2)≈32  K interactions, both significantly larger than previous estimates. The ratio α=|J(2)/J(1)|=0.19±0.01 places the system close to the critical point α(c)=0.25 of the J(1)-J(2) chain but in the 1D ferromagnetic regime. We establish that the vicinity to criticality only marginally affects the dispersion and coherence of the spin-wave-like magnetic excitations but instead results in a dramatic T dependence of high-energy Zhang-Rice singlet excitation intensities.

Evidence for the importance of extended Coulomb interactions and forward scattering in cuprate superconductors

The prevalent view of the high-temperature superconducting cuprates is that their essential low-energy physics is captured by local Coulomb interactions. However, this view been challenged recently by studies indicating the importance of longer-range components. Motivated by this, we demonstrate the importance of these components by examining the electron-phonon (e-ph) interaction with acoustic phonons in connection with the recently discovered renormalization in the near-nodal low-energy (~8-15 meV) dispersion of Bi(2)Sr(2)CaCu(2)O(8+δ). By studying its nontrivial momentum and doping dependence we conclude a predominance of forward scattering arising from the direct interplay between the e-ph and extended Coulomb interactions. Our results thus demonstrate how the low-energy renormalization can provide a pathway to new insights into how these interactions interplay with one another and influence pairing and dynamics in the cuprates.

Measurement of the neutron radius of 208Pb through parity violation in electron scattering

We report the first measurement of the parity-violating asymmetry A(PV) in the elastic scattering of polarized electrons from 208Pb. A(PV) is sensitive to the radius of the neutron distribution (R(n)). The result A(PV)=0.656±0.060(stat)±0.014(syst) ppm corresponds to a difference between the radii of the neutron and proton distributions R(n)-R(p)=0.33(-0.18)(+0.16) fm and provides the first electroweak observation of the neutron skin which is expected in a heavy, neutron-rich nucleus.

Comparison of bacterial identification by MALDI-TOF mass spectrometry and conventional diagnostic microbiology methods: agreement, speed and cost implications

Identification of microbial pathogens still relies primarily on culture and phenotypic methods, which is labour-intensive and time-consuming. In this study, identification of bacteria with valid standard identification using BD Phoenix, API panels and other recommended procedures is compared to identification with matrix-assisted laser desorption/ionisation-time of flight (MALDI-TOF) mass spectrometry using the MALDI Biotyper (Bruker Daltonics) in the setting of a routine NHS diagnostic microbiology laboratory. In total, 928 bacterial isolates obtained from blood (n=463), wounds and pus (n=208), respiratory tract (n=100), faeces (n=86) and urines (n=71) were analysed. There were 721 (77.7%) isolates with a MALDI Biotyper score > or =2.0, indicating secure genus and probable species identification; and 149 (16.1%) isolates with a score > or =1.7 and <2.0 indicating probable genus identification. The isolates with scores of > or =2.0 and > or =1.7 comprised 31 and 33 genera and 65 and 67 species, respectively. Overall, 99.4% and 99.1% of organism identifications were in agreement between the MALDI Biotyper and conventional identification at the genus level, and 89.3% and 87.8% at species level when analysing organisms with MALDI Biotyper scores > or =2.0 and > or =1.7, respectively. With many but not all organisms, identification at the genus level is sufficient; however, MALDI Biotyper separation of 208 staphylococci into Staphylococcus aureus and coagulase-negative staphylococci was always correct when scores were > or =1.7. First results were obtained after 5-10 min and analysis of a full 96-well target plate was completed in approximately 90 min. Substantial savings of between pounds 1.79 and pounds 2.56 per isolate, depending on the cost model of acquisition of the MALDI Biotyper system and number of isolates tested, would be realised when all 928 isolates were identified using the MALDI Biotyper and disk-susceptibility testing when compared to the cost for 618 Phoenix ID panels and 158 API panels and disk-susceptibility tests only (i.e., not taking into account costs incurred for identification of the remaining 152 mixed isolates). Microbial identification by MALDI Biotyper offers a rare opportunity for significant cost-neutral or even cost-saving quality improvements in medical diagnostics.

OT1-02-03: EGF114299: Safety and Efficacy of an Aromatase Inhibitor (AI) in Combination with Lapatinib (L), Trastuzumab (T) or Both for the Treatment of Hormone Receptor-Positive (HR+), HER2+ Metastatic Breast Cancer (MBC)

Background: Data from the L plus letrozole (EGF30008) and the Trastuzumab and Anastrozole Directed Against ER-Positive HER2−Positive Mammary Carcinoma (TaNDEM) studies demonstrated that HER2 targeted and endocrine therapy (ET) is a better strategy than ET alone. In EGF30008, progression-free survival (PFS) in the HER2+ population was statistically significantly longer in the letrozole plus L group compared with the letrozole plus placebo group. The HR was 0.71 (95% CI: 0.53−0.96; stratified log rank P=.019). Median PFS was 35.4 weeks in the letrozole plus L group compared with 13.0 weeks in the letrozole plus placebo group.

The present study (EGF114299) is a phase III, open-label, multicenter trial designed to evaluate benefit in overall survival (OS) provided by L/T/AI and L/AI, in pts with HR+/HER2+ MBC who have received neo-/adjuvant T and ET. It will also provide further data on dual HER2 suppression in an attempt to prevent acquired endocrine resistance.

Trial Design: Pts will be randomized to 1 of 3 treatment arms: L 1000 mg po QD plus T (loading dose of 8 mg/kg followed by maintenance with 6 mg/kg IV q3w plus an AI po QD); T plus an AI; or L 1500 mg po QD plus an AI). Choices of AI include letrozole, anastrozole, or exemestane.

Eligibility Criteria: HR+ (ER and/or PgR) and HER2+ Stage IV MBC pts are to be enrolled. Pts must have received neo-/adjuvant T and ET, and are treatment naive for MBC.

Specific Aims: The primary objective is to evaluate OS of L/T/AI as compared with T/AI. The secondary objectives are to assess: OS in T/AI vs L/AI and T/L/AI vs L/AI; PFS; overall response rate; clinical benefit rate; safety and tolerability; and QoL relative to baseline. A 4-year recruitment is anticipated. More than 200 centers across 25 countries are planned; approximately 50 centers are currently open for enrollment.

Statistical Methods: The study is powered to detect a 42% improvement in the risk of death (HR=0.70) in all pts receiving L/T/AI (median 28.5 months) compared with T/AI (median 20 months). The hypothesis will be tested using a 1-sided test for superiority with a=0.025 with a power of 80%.

Present and Target Accrual: One (1) of 525 pts has been randomized. The majority of eligible pts may reside in countries where T is commercially available and reimbursable, particularly North America and Western Europe. Patients who have participated in previous neo-/adjuvant trials including a T regimen are eligible, provided they meet all other inclusion criteria.

The study is currently recruiting pts, with an anticipated target accrual of 525 patients by March 2016.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr OT1-02-03.