Abstract PD6-03: High prevalence and clonal heterogeneity of ESR1 mutations (mt) in circulating tumor DNA (ctDNA) from patients (pts) enrolled in FERGI, a randomized phase II study testing pictilisib (GDC-0941) in combination with fulvestrant (F) in pts that failed a prior aromatase inhibitor (AI)

Background: Mutations in the ligand binding domain of the estrogen receptor gene (ESR1) have been associated with resistance to AI therapy in pts with ER+ breast cancer. To assess if ESR1 status has prognostic or predictive significance in the post-AI metastatic setting ESR1 mutation status was analyzed in circulating tumor DNA (ctDNA) from 168 pts enrolled on the FERGI study (NCT01437566; Krop et al., SABCS 2014).

Methods: Baseline and longitudinal mutational analysis for hotspot mutations in ESR1 (E380Q, S463P, V534E, P535H, L536R/H/P, L536Q, Y537N/S/C, D538G) and PIK3CA (C420R, E542K, E545K/G, Q546K, M1043I, H1047Y/R/L) was performed using droplet digital PCR (ddPCR) on ctDNA derived from plasma. Archival tissue was analyzed via RT-PCR and ddPCR.

Results: Baseline ctDNA analysis demonstrated a total of 62/156 (40%) and 57/153 (37%) pts with PIK3CA and ESR1 mutations, respectively. The most common ESR1 mutations are D538G, Y537S, and E380Q, representing 54%, 33% and 26% of the pts with a detectable ESR1 mutation at baseline, respectively. There was a numeric increase of ESR1 mutations in patients with LumA (41/99, 41%) vs LumB disease (14/44, 31%). PIK3CA mutations in asynchronously collected archival tissue were 85% concordant with plasma ctDNA mutations (sensitivity 78%, specificity 91%). PIK3CA mutations in baseline ctDNA showed a higher median allele frequency (AF) than ESR1 mutations (3.6% vs 0.46%), consistent with PIK3CA being an early event and ESR1 mutations occurring later in pts with recurrent disease. Of the pts with a detectable ESR1 mutation at baseline (n=57), 23 (40%) pts had multiple ESR1 mutations and 10 (18%) had ≥3 ESR1 mutations. The PFS outcomes for patients with and without ESR1 mutations detected at baseline are summarized below, indicating no obvious prognostic or predictive effect for combination of F with pictilisib compared with F in these underpowered subsets.

ArmESR1 MT - mPFS (mo)ESR1 WT - mPFS (mo)HR (95% CI)F + placebo5.4 (30 pts, 24 events)3.7 (40 pts, 31 events)1.06 (0.62, 1.81)F+pictilisib5.8 (27 pts, 20 events)6.7 (56 pts, 34 events)1.36 (0.78, 2.38)

PIK3CA and ESR1 ctDNA analysis on serial plasma samples from 40 pts and the assessment of ESR1 mutation status in the patient's tumor sample by ddPCR is currently in progress and will be reported.

Conclusions: Mutations in ESR1 detected by ddPCR in patient plasma samples occur in nearly 40% of pts that failed a prior AI. The polyclonal nature of ESR1 mutations is consistent with the convergent evolution of multiple AI resistant subclones. While these conclusions should be interpreted with caution due to the relatively small sample size and post hoc nature of the analysis, this data does not support a prognostic or predictive PFS hypothesis for ESR1 mutations with F or in combination with pictilisib.

Citation Format: Spoerke J, Gendreau S, Johnston S, Schmid P, Krop I, Qui J, Derynck M, Chan I, Walter K, Amler L, Hampton G, Lackner M. High prevalence and clonal heterogeneity of ESR1 mutations (mt) in circulating tumor DNA (ctDNA) from patients (pts) enrolled in FERGI, a randomized phase II study testing pictilisib (GDC-0941) in combination with fulvestrant (F) in pts that failed a prior aromatase inhibitor (AI). [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr PD6-03.

Withdrawal of anticancer therapy in advanced disease: a systematic literature review

Background

Current guidelines set out when to start anticancer treatments, but not when to stop as the end of life approaches. Conventional cytotoxic agents are administered intravenously and have major life-threatening toxicities. Newer drugs include molecular targeted agents (MTAs), in particular, small molecule kinase-inhibitors (KIs), which are administered orally. These have fewer life-threatening toxicities, and are increasingly used to palliate advanced cancer, generally offering additional months of survival benefit. MTAs are substantially more expensive, between £2-8 K per month, and perceived as easier to start than stop.

Methods

A systematic review of decision-making concerning the withdrawal of anticancer drugs towards the end of life within clinical practice, with a particular focus on MTAs. Nine electronic databases searched. PRISMA guidelines followed.

Results

Forty-two studies included. How are decisions made? Decision-making was shared and ongoing, including stopping, starting and trying different treatments. Oncologists often experienced ‘professional role dissonance’ between their self-perception as ‘treaters’, and talking about end of life care. Why are decisions made? Clinical factors: disease progression, worsening functional status, treatment side-effects. Non-clinical factors: physicians’ personal experience, values, emotions. Some patients continued treatment to maintain ‘hope’, often reflecting limited understanding of palliative goals. When are decisions made? Limited evidence reveals patients’ decisions based upon quality of life benefits. Clinicians found timing withdrawal particularly challenging. Who makes the decisions? Decisions were based within physician-patient interaction.

Conclusions

Oncologists report that decisions around stopping chemotherapy treatment are challenging, with limited evidence-based guidance outside of clinical trial protocols. The increasing availability of oral MTAs is transforming the management of incurable cancer; blurring boundaries between active treatment and palliative care. No studies specifically addressing decision-making around stopping MTAs in clinical practice were identified. There is a need to develop an evidence base to support physicians and patients with decision-making around the withdrawal of these high cost treatments.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-015-1862-0) contains supplementary material, which is available to authorized users.

Abiraterone acetate, exemestane or the combination in postmenopausal patients with estrogen receptor-positive metastatic breast cancer

Resistance to nonsteroidal aromatase inhibitors is a major obstacle in the management of estrogen receptor-positive postmenopausal metastatic breast cancer. The addition of abiraterone acetate to exemestane did not improve clinical outcomes compared with exemestane alone in an androgen receptor-enriched population, potentially due to induced serum progesterone as a resistance mechanism.

Background

Androgen receptor (AR) signaling and incomplete inhibition of estrogen signaling may contribute to metastatic breast cancer (MBC) resistance to a nonsteroidal aromatase inhibitor (NSAI; letrozole or anastrozole). We assessed whether combined inhibition of androgen biosynthesis with abiraterone acetate plus prednisone and estradiol synthesis with exemestane (E) may be of clinical benefit to postmenopausal patients with NSAI-pretreated estrogen receptor-positive (ER+) MBC.

Patients and methods

Patients (N = 297) were stratified by the number of prior therapies for metastatic disease (0–1 versus 2) and by prior NSAI use (adjuvant versus metastatic), and randomized (1 : 1 : 1) to receive oral once daily 1000 mg abiraterone acetate plus 5 mg prednisone (AA) versus AA with 25 mg E (AAE) versus 25 mg E alone (E). Each treatment arm was well balanced with regard to the proportion of patients with AR-positive breast cancer. The primary end point was progression-free survival (PFS). Secondary end points included overall survival, clinical benefit rate, duration of response, and overall response rate.

Results

There was no significant difference in PFS with AA versus E (3.7 versus 3.7 months; hazard ratio [HR] = 1.1; 95% confidence interval [CI] 0.82–1.60; P = 0.437) or AAE versus E (4.5 versus 3.7 months; HR = 0.96; 95% CI 0.70–1.32; P = 0.794). Increased serum progesterone concentrations were observed in both arms receiving AA, but not with E. Grade 3 or 4 treatment-emergent adverse events associated with AA, including hypokalemia and hypertension, were less common in patients in the E (2.0% and 2.9%, respectively) and AA arms (3.4% and 1.1%, respectively) than in the AAE arm (5.8% for both).

Conclusions

Adding AA to E in NSAI-pretreated ER+ MBC patients did not improve PFS compared with treatment with E. An AA-induced progesterone increase may have contributed to this lack of clinical activity.

ClinicalTrials.gov

NCT01381874.

An apparatus to manipulate and identify individual Ba ions from bulk liquid Xe

We describe a system to transport and identify barium ions produced in liquid xenon, as part of R&D towards the second phase of a double beta decay experiment, nEXO. The goal is to identify the Ba ion resulting from an extremely rare nuclear decay of the isotope (136)Xe, hence providing a confirmation of the occurrence of the decay. This is achieved through Resonance Ionization Spectroscopy (RIS). In the test setup described here, Ba ions can be produced in liquid xenon or vacuum and collected on a clean substrate. This substrate is then removed to an analysis chamber under vacuum, where laser-induced thermal desorption and RIS are used with time-of-flight mass spectroscopy for positive identification of the barium decay product.

Radiation-induced morphoea treated with UVA-1 phototherapy

Morphoea is a localized inflammatory disorder of the dermis and subcutaneous fat and radiotherapy is a rarely reported cause (estimated incidence of 2 per 1000). Morphoea is commonly mistaken for an inflammatory recurrence of breast cancer, resulting in unnecessary investigations and treatment. We report the case of a 40-year-old woman who developed radiation-induced morphoea of the breast 7 months following adjuvant radiotherapy. She was treated with topical and systemic steroids as well as psoralen plus ultraviolet (UV)A before proceeding to UVA1 phototherapy. We also review the literature and discuss other management options.

Assessment of microtubule-associated protein (MAP)-Tau expression as a predictive and prognostic marker in TACT; a trial assessing substitution of sequential docetaxel for FEC as adjuvant chemotherapy for early breast cancer

The TACT trial is the largest study assessing the benefit of taxanes as part of adjuvant therapy for early breast cancer. The goal of this translational study was to clarify the predictive and prognostic value of Tau within the TACT trial. Tissue microarrays (TMA) were available from 3,610 patients. ER, PR, HER2 from the TACT trial and Tau protein expression was determined by immunohistochemistry on duplicate TMAs. Two parallel scoring systems were generated for Tau expression ('dichotomised' vs. 'combined' score). The positivity rate of Tau expression was 50 % in the trial population (n = 2,483). Tau expression correlated positively with ER (p < 0.001) and PR status (p < 0.001); but negatively with histological grade (p < 0.001) and HER2 status (p < 0.001). Analyses with either scoring systems for Tau expression demonstrated no significant interaction between Tau expression and efficacy of docetaxel. Contrary to the hypothesis that taxane benefit would be enriched in Tau negative/low patients, the only groups with a suggestion of a reduced event rate in the taxane group were the HER2-positive, Tau positive subgroups. Tau expression was seen to be a prognostic factor on univariate analysis associated with an improved DFS, independent of the treatment group (p < 0.001). It had no prognostic value in ER-negative tumours and the weak prognostic effect of Tau in ER-positive tumours (p = 0.02) diminished, when considering ER as an ordinal variable. On multivariable analyses, Tau had no prognostic value in either group. In addition, no significant interaction between Tau expression and benefit from docetaxel in patients within the PR-positive and negative subsets was seen. This is now the second large adjuvant study, and the first with quantitative analysis of ER and Tau expression, failing to show an association between Tau and taxane benefit with limited utility as a prognostic marker for Tau in ER-positive early breast cancer patients.

Abstract P1-08-14: HER2 extracellular domain (ECD): A predictive marker of lapatinib treatment benefit in advanced breast cancer

Pretreatment serum HER2 ECD may be associated with clinical outcome to lapatinib therapy and may also have treatment-independent prognostic value. We performed a meta-analysis to examine the prognostic and predictive role of baseline ECD (bECD) levels for lapatinib therapy. We also compared and contrasted its role with tumor HER2 status.

We analyzed bECD and tumor HER2 data in 1902 of 2264 patients (84%) with advanced breast cancer who were randomly assigned to receive lapatinib-containing therapy or control treatment in three clinical trials: EGF30001 (lapatinib and paclitaxel vs paclitaxel), EGF30008 (lapatinib and letrozole vs letrozole), and EGF100151 (lapatinib and capecitabine vs capecitabine). bECD was centrally measured by enzyme linked immunoassay and tumor HER2 was centrally determined by immunohistochemistry and fluorescence in situ hybridization. bECD and tumor HER2 status were examined for associations with objective tumor response (ORR), progression-free survival (PFS) and overall survival (OS) in the treatment groups.

Of the patients with both bECD and tumor HER2 data, 31% had HER2 bECD≥15 ng/mL and 28% had HER2+ cancer. The effectiveness of lapatinib-containing therapy was significantly associated with bECD level (treatment-bECD interaction P&lt;0.001 [ORR], P&lt;0.001 [PFS]). In patients with bECD≥15 ng/mL, lapatinib-containing therapy, compared to control, significantly improved ORR (odds ratio [OR] for complete and partial response, 1.88; P = 0.001) and PFS (hazards ratio [HR] for progression or death, 0.69; P&lt;0.001). Among patients with bECD&lt;15 ng/mL, there was no significant difference between treatment groups for ORR (OR, 1.17; P = 0.19) or PFS (HR, 0.93; P = 0.30). The effectiveness of lapatinib-containing therapy was also significantly associated with HER2 tumor status for ORR (OR [HER2+] 2.39, P&lt;0.001; OR [HER2-] 1.10, P = 0.43; treatment-HER2 interaction P = 0.001) and PFS (HR [HER2+] 0.63, P&lt;0.001; HR [HER2-] 0.95, P = 0.46; treatment-HER2 interaction P&lt;0.001). When bECD and HER2 tumor status were examined together, the effectiveness of lapatinib-containing therapy was significantly associated with both bECD and HER2 tumor status for PFS (treatment-biomarker interaction P = 0.02[HER2], P = 0.001[bECD]) but only for bECD for ORR (treatment-biomarker interaction P = 0.07 [HER2], P = 0.003 [bECD]). The effectiveness of lapatinib-containing therapy was not significantly associated with OS for both biomarkers (treatment-biomarker interaction P = 0.30 [bECD] and P = 0.80 [HER2]). In the control groups, bECD≥15 ng/mL (HR 1.35, P = 0.003) and HER2+ (HR 1.67, P&lt;0.001) were associated with shorter PFS after adjusting for other baseline characteristics. bECD≥15 ng/mL (HR 1.89, P&lt;0.001) but not HER2+ (HR 0.97, P = 0.81) was associated with shorter OS after adjusting for other baseline characteristics.

Lapatinib therapy was associated with higher ORR and longer PFS in patients with elevated ECD levels. Elevated ECD was also associated with shorter PFS and OS in patients treated with non-lapatinib therapy. ECD provided additional predictive and prognostic information, in addition to tumor HER2 status, that if validated, could aid in treatment decisions. The predictive role of ECD in other anti-HER2 therapies requires further research.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P1-08-14.

Quantifying many-body effects by high-resolution Fourier transform scanning tunneling spectroscopy

High-resolution Fourier transform scanning tunneling spectroscopy (FT-STS) is used to study many-body effects on the surface state of Ag(111). Our results reveal a kink in the otherwise parabolic band dispersion of the surface electrons and an increase in the quasiparticle lifetime near the Fermi energy Ef. The experimental data are accurately modeled with the T-matrix formalism for scattering from a single impurity, assuming that the surface electrons are dressed by the electron-electron and electron-phonon interactions. We confirm the latter as the interaction responsible for the deviations from bare dispersion. We further show how FT-STS can be used to simultaneously extract real and imaginary parts of the self-energy for both occupied and unoccupied states with a momentum and energy resolution competitive with angle-resolved photoemission spectroscopy. From our quantitative analysis of the data we extract a Debye energy of ℏΩD=14±1  meV and an electron-phonon coupling strength of λ=0.13±0.02, consistent with previous results. This proof-of-principle measurement advances FT-STS as a method for probing many body effects, which give rise to a rich array of material properties.

Andreas Vesalius and Thomas Willis: their anatomic brain illustrations and illustrators

The brain illustrations of Vesalius and Willis were the first in anatomic history with pictorial accuracy. Their illustrations, illustrators, and methods are discussed. Woodcut blocks were used for the prints of figures in the Vesalian anatomy. Figures of the brain appear to be done after external fixation in the work of Willis.

Incorporating New Materials and Techniques into Clinical Practice

This article outlines the subjects presented and discussed at the December 2012 IADR Dental Materials Innovation Workshop held at King’s College London. Incorporating new materials and techniques into clinical practice was considered from 4 perspectives: (1) Accelerating the “research to regulatory approval” process was presented with current developments in the United States, with the National Institutes of Health/Food and Drug Administration process as a working example; (2) intellectual property and regulatory requirements were discussed across the well-established US and EU frameworks, as well as the more recently developed procedures across Brazil, Russia, India, and China; (3) the challenges and opportunities of incorporating innovations into dental education were considered with reference to the future needs of both students and faculty; and (4) the key but difficult and unpredictable step of translating such innovations into routine dental practice was then explored. Constructive and far-ranging discussion among the broadly based Workshop participants (from dental research, education, practice, and industry, as well as environmental organizations and the World Health Organization) mapped out key issues for the future. The focus was on facilitating the more timely adoption of improvements in both materials and techniques to improve patient health and health systems, while minimizing environmental impact.

Role of lattice coupling in establishing electronic and magnetic properties in quasi-one-dimensional cuprates

High resolution resonant inelastic x-ray scattering has been performed to reveal the role of lattice coupling in a family of quasi-1D insulating cuprates, Ca2+5xY2-5xCu5O10. Site-dependent low-energy excitations arising from progressive emissions of a 70 meV lattice vibrational mode are resolved for the first time, providing a direct measurement of electron-lattice coupling strength. We show that such electron-lattice coupling causes doping-dependent distortions of the Cu-O-Cu bond angle, which sets the intrachain spin exchange interactions. Our results indicate that the lattice degrees of freedom are fully integrated into the electronic behavior in low-dimensional systems.

170 ASSESSMENT OF FRESH AND FROZEN - THAWED BOTTLENOSE DOLPHIN (TURSIOPS TRUNCATUS) SPERM DNA FRAGMENTATION USING THE SPERM CHROMATIN DISPERSION TEST

There has been significant development over the last 20 years to improve genetic management of the captive bottlenose dolphin (Tursiops truncatus) by means of genome resource banking and assisted reproduction. Although standard semen parameters have been analysed in some detail, very little is known about sperm DNA fragmentation (SDF) in this species. The aim of this study was to develop a sperm chromatin dispersion test (SCDt) for the bottlenose dolphin to establish the baseline level of SDF immediately after ejaculation and cryopreservation and to determine the dynamic loss of sperm DNA quality after ex vivo handing and incubation in conditions that mimic the female reproductive tract. Semen from 8 bottlenose dolphins was collected by manual stimulation. Initial validation of the SCDt was conducted by means of in situ nick translation and neutral comet assay using a proven fertile male. To investigate the dynamic loss of sperm chromatin (rate of sDF loss), thawed sperm samples were incubated at 37.9°C for up to 48 h, and aliquots of spermatozoa were assessed after 1, 4, 8, 24, and 48 h. Dolphin sperm nuclei with fragmented DNA exhibited large halos of dispersed DNA fragments, whereas those with nonfragmented DNA displayed small halos of nondispersed DNA. A high correlation (r2 = 0.82; P ≤ 0.01) was found between the respective assessments of the SCDt and the neutral comet assay. All nucleoids resulting in a large halo of dispersed chromatin were intensely positive to in situ nick translation. The level of sDF fragmentation observed immediately after ejaculation in fresh and frozen samples was relatively low (1–5%). After comparing different ejaculates of the same individual, differences were found. Chromatin stability was high during the first 48 h of ejaculation or post-thawing and incubation. Evaluation of the sDF dynamics of fresh and frozen–thawed spermatozoa revealed no significant increase in the baseline level of sDF or in the relative increase of DNA damage after 48 h of incubation. Our data suggest that cryopreservation does not induce a dramatic increase in sperm chromatin damage. Interestingly, sperm samples derived from aged animals resulted in an increased rate of DNA loss, which was observed after 60 min post-incubation.