Abstract P3-07-57: Development of a 6-gene qPCR RUO-validated assay as a predictive biomarker for response of vantictumab (OMP-18R5; anti-frizzled) in HER2- breast cancer patients

Background: We have developed a monoclonal antibody, vantictumab that blocks canonical WNT/β-catenin signaling through binding of five FZD receptors (1, 2, 5, 7, 8). This antibody inhibits the growth of several tumor types, including breast. Vantictumab reduces tumor-initiating cell frequency and exhibits synergistic activity with standard-of-care (SOC) agents (Gurney et al, 2012). To target breast cancer patients most likely to respond to vantictumab, we undertook a predictive biomarker study.

Methods: We have identified a 6-gene Wnt pathway-related signature, FBXW2, CCND2, RHOU, CTBP2, WIF1, and DKK1, based on microarray gene expression data from 8 breast cancer patient derived xenograft (PDX) models with established in vivo response to vantictumab plus SOC. This signature successfully predicted the response of 8 additional and independent PDX breast tumors. We further developed a qPCR Research Use Only (RUO) assay for the 6 genes to be used on FFPE human breast tumor samples. Multiple assays targeting different regions spanning each mRNA transcript were tested and selected based on PCR efficiency, specificity and sensitivity. We compared assay sensitivity under different cDNA synthesis and pre-amplification conditions: random vs. gene-specific priming, number of pre-amplification cycles, pre-amplification reaction volumes, and cDNA synthesis kits. A repeatability study was performed to test assay performance. The pre-amplification and PCR were repeated over three separate days and across two independent labs.

Results: Our results showed that cDNA synthesis by gene-specific priming followed by 18 cycles of pre-amplification performed the best and the assay is robust with minimal starting FFPE RNA input. The results of the repeatability study were consistent among the different days and the different labs (<5% CV). Using the 6-gene qPCR RUO assay, the signature score from the microarray data was further refined using 12 PDX HER2- breast tumors with known in vivo response to vantictumab with SOC. The prevalence of the 6-gene signature was established using ∼100 HER2- breast cancer samples.

Conclusions: A robust 6-gene RUO-validated assay was developed as a predictive biomarker for vantictumab in HER2- breast cancer. The assay is currently being evaluated in a Phase 1b study of vantictumab with paclitaxel in HER2- breast cancer.

Citation Format: Zhang C, O'Young G, Wikstrom K, Davison T, Yeung P, Cattaruzza F, Yen W-C, Hoey T, Lewicki J, Rachmann R, Kerr P, Hill L, Eason R, McErlean S, Liu Y, Kapoun AM. Development of a 6-gene qPCR RUO-validated assay as a predictive biomarker for response of vantictumab (OMP-18R5; anti-frizzled) in HER2- breast cancer patients. [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 P3-07-57.

Accuracy and precision of direct bone conduction measurements

OBJECTIVES

Variability in Baha® sound processor fittings arise from several sources including the nature of the implant-to-bone transmission and transcranial attenuation in patients with single-sided sensorineural deafness. One method of improving the predictability of Baha fittings is to measure the individual patient's actual bone conduction thresholds via the implant, thereby removing the influence of skin thickness and/or implant location site.

METHODOLOGY

One hundred thirty eight adult wearers of the Baha System participated in the study. Direct bone conduction thresholds were obtained through the BC Direct feature of the Cochlear™ Baha Fitting Software combined with the CochlearBaha BP100 sound processor. Test-retest reliability measurement was performed in 58 participants.

RESULTS

Improved transmission of sound through the implant rather than transcutaneously through the skin was confirmed. On average, the BC Direct thresholds were closer to the patient's unmasked thresholds than the masked values. In patients with single-sided sensorineural deafness, BC Direct results were elevated compared to the contralateral bone conduction thresholds due to transcranial attenuation. The test-retest reliability for the BC Direct measurements was within ±5 dB, which is in within the accepted variability for audiometric test measurements.

CONCLUSIONS

Direct bone conduction measurement provides a validated method of comparing the transcutaneous thresholds as measured through audiometry with the percutaneous responses from the Baha sound processor. The Baha fitting based on direct measurements of bone conduction may require less fine-tuning and provide a greater understanding of the variability of the bone conduction sound pathway.

Direct excitation of propagating spin waves by focused ultrashort optical pulses

An all-optical experiment long utilized to image phonons excited by ultrashort optical pulses has been applied to a magnetic sample. In addition to circular ripples due to surface acoustic waves, we observe an X-shaped pattern formed by propagating spin waves. The emission of spin waves from the optical pulse epicenter in the form of collimated beams is qualitatively reproduced by micromagnetic simulations. We explain the observed pattern in terms of the group velocity distribution of Damon-Eshbach magnetostatic spin waves in the reciprocal space and the wave vector spectrum of the focused ultrafast laser pulse.

A comparison of batch effect removal methods for enhancement of prediction performance using MAQC-II microarray gene expression data

Batch effects are the systematic non-biological differences between batches (groups) of samples in microarray experiments due to various causes such as differences in sample preparation and hybridization protocols. Previous work focused mainly on the development of methods for effective batch effects removal. However, their impact on cross-batch prediction performance, which is one of the most important goals in microarray-based applications, has not been addressed. This paper uses a broad selection of data sets from the Microarray Quality Control Phase II (MAQC-II) effort, generated on three microarray platforms with different causes of batch effects to assess the efficacy of their removal. Two data sets from cross-tissue and cross-platform experiments are also included. Of the 120 cases studied using Support vector machines (SVM) and K nearest neighbors (KNN) as classifiers and Matthews correlation coefficient (MCC) as performance metric, we find that Ratio-G, Ratio-A, EJLR, mean-centering and standardization methods perform better or equivalent to no batch effect removal in 89, 85, 83, 79 and 75% of the cases, respectively, suggesting that the application of these methods is generally advisable and ratio-based methods are preferred.

Bone-anchored hearing aid modified with directional microphone: do patients benefit?

BACKGROUND

Bone-anchored hearing aids are well established in the treatment of patients with a conductive or mixed hearing loss. However, one of the main problems is that of sound localisation. This can be improved with a directional microphone. This study compared the quality of life of bone-anchored hearing aid wearers before and after the use of a directional microphone.

METHOD

Eleven patients were included. They were required to wear the directional microphone for 12 weeks. Quality of life was measured using the Glasgow benefit inventory questionnaire, before and after the study period.

RESULTS

The response rate was 82 per cent. The total benefit from the directional microphone was +49.7. The three components of the Glasgow benefit inventory were analysed separately, as follows: general subscale +57.4; physical health +42.6; and social scale +25.9.

CONCLUSION

This is the first study to demonstrate a significant improvement in quality of life from a directional microphone fitted to a bone-anchored hearing aid.

Maternal satisfaction with active management of labor: a randomized controlled trial

BACKGROUND

Active management of labor reduces the length of labor and rate of prolonged labor, but its effect on satisfaction with care, within a randomized controlled trial, has not previously been reported. The study objectives were to establish if a policy of active management of labor affected any aspect of maternal satisfaction, and to determine the independent explanatory variables for satisfaction with labor care in a low-risk nulliparous obstetric population.

METHODS

Nulliparous women at National Women's Hospital in Auckland, New Zealand, in spontaneous labor at term with singleton pregnancy, cephalic presentation, and without fetal distress were randomized after the onset of labor to active management (n = 320) or routine care (n = 331). Active management included early amniotomy, two-hourly vaginal assessments, and early use of high dose oxytocin for slow progress in labor. Routine care was not prespecified. Maternal satisfaction with labor care was assessed by postal questionnaire at 6 weeks postpartum. Sensitivity analyses were performed, and logistic regression models were developed to determine independent explanatory variables for satisfaction.

RESULTS

Of the 651 women randomized in the trial, 482 (74%) returned the questionnaires. Satisfaction with labor care was high (77%) and did not significantly differ by treatment group. This finding was stable when sensitivity analysis was performed. The first logistic regression model found independent associations between satisfaction and adequate pain relief, one-to-one midwifery care, adequate information and explanations by staff, accurate expectation of length of labor, not having a postpartum hemorrhage, and fewer than three vaginal examinations during labor. The second model found fewer than three vaginal examinations and one-to-one midwifery care as significant explanatory variables for satisfaction with labor care.

CONCLUSIONS

Active management did not adversely affect women's satisfaction with labor and delivery care in this trial. Future studies should concentrate on measurement of potential predictors before and during labor.

Bone-anchored hearing aid quality of life assessed by Glasgow Benefit Inventory

OBJECTIVE/HYPOTHESIS

The bone-anchored hearing aid (BAHA) is a well established mode of treatment and many studies show the audiological benefit, but none has assessed the benefit to the quality of life of patients. This study uses the validated Glasgow Benefit Inventory to quantify the changes in quality of life.

STUDY DESIGN

Retrospective questionnaire study.

METHODS

Sixty consecutive patients receiving treatment with BAHA were enrolled in the study. The male/female ratio was 1.26 to 1; mean patient age was 45 years. The most common indication was hearing loss secondary to mastoid disease and surgery followed by congenital atresia and chronic discharge from the ear.

RESULTS

The response rate was 85%, which is high and adds weight to the results. The general benefit score was +34 (range, +27-+48), which is comparable to middle ear surgery but just below benefit from cochlear implantation. The social benefit was +21 (range, +12-+37) with only +10 (range, +2-+26) for the physical score. This pattern mirrors that reported for other ear interventions. Maximum benefit was noted in patients with congenital atresias followed by discharging mastoid cavities.

CONCLUSION

This study is the first to demonstrate significant quality of life benefit from BAHA surgical intervention as measured by the Glasgow Benefit Inventory.

Bone-anchored hearing aid: quality of life assess by glasgow benefit inventory

INTRODUCTION: The bone-anchored hearing aid (BAHA) uses the system of osseointegration described by Branemark. It is a well-established mode of treatment and many studies show the audiological benefit, but none have assessed the benefit to the quality of life of patients who underwent this surgical intervention. This study uses the validated Glasgow Benefit Inventory (GBI) to quantify the changes in quality of life. The GBI is a specific patient-orientated questionnaire designed to look at the changes in health status secondary to an ORL intervention.1 The GBI gives an overll scorek, but also subscores of general, social and physical benefits. METHOD: Sixty consecutive BAHA patients were enrolled in the study. The male: female ratio was 1 : 26, with a mean age of 45 years. The most common indication was hearing loss secondary to mastoid disease/surgery followed by congenital atresia and chronically discharging ear. The mean bone conduction of the better ear was 19 dB and the mean conductive loss across the speech frequencies was 58 dB. Only patients who were fitted with the classic model were included in the study. RESULTS: The response rate was > 70%, which is high and adds weight to the results. The general benefit score was + 40 which is comparable to middle ear surgery, but just below benefit from chochlear implantation. The social benefit was + 27 with only + 10 for the physical score. This pattern mirrors that reported for other ear interventions. CONCLUSION: This paper is the first to demonstrate that there is significant quality of life benefit from BAHA surgical intervention as measured by the GBI.

A randomised controlled trial and meta-analysis of active management of labour

OBJECTIVE

To test whether a policy of active management of nulliparous labour would reduce the rate of caesarean section and prolonged labour without influencing maternal satisfaction.

DESIGN

Randomised controlled trial.

SETTING

Tertiary referral obstetric unit, Auckland, New Zealand.

POPULATION

Nulliparous women in spontaneous labour at term with singleton pregnancy and cephalic presentation and without fetal distress.

METHODS

After the onset of active labour, previously consented women were randomly assigned to active management (n = 320) or to routine care (n = 331). Active labour was defined as regular painful contractions, occurring at least once in five minutes, lasting at least 40 seconds, accompanied by either spontaneous rupture of the membranes, or full cervical effacement and dilatation of at least two centimetres. Active management included early amniotomy, two-hourly vaginal assessments, and early use of high dose oxytocin for slow progress in labour. Routine care was not prespecified. Prolonged labour was > 12 hours duration. Maternal satisfaction with labour care was assessed by postal questionnaire at six weeks postpartum.

MAIN OUTCOME MEASURES

Mode of delivery, duration of labour, and maternal satisfaction.

RESULTS

Active management of labour did not reduce the rate of caesarean section 30/320 (9.4%), compared with 32/331 (9.7%) for routine care, but did shorten the length of first stage of labour (median 240 min vs 290 min; P = 0.02), and reduce the relative risk of prolonged labour (RR 0.39; 95% CI 0.22, 0.71). There were no differences between groups in the rates of newborn nursery admission, neonatal acidosis, low Apgar scores, or postpartum haemorrhage. Satisfaction with labour care was high (77%) and did not differ between groups.

CONCLUSIONS

Active management of labour reduced the duration of the first stage of labour without affecting the rate of caesarean section, maternal satisfaction, or other maternal or newborn morbidity.

The effect of electrode position in electrocochleography

This study assessed the effect of needle electrode position on the human cochlear summating potential (SP) obtained by transtympanic electrocochleography (ECochG). Electrocochleography was performed on 10 subjects with large central tympanic membrane perforations with good cochlear function, and in whom a needle electrode could be accurately placed in a series of five pre-determined positions in the middle ear. A comparison of the electrocochleograms revealed a wide scatter of results between different positions in the same patient and between similar positions in different patients. Only when the needle was repositioned at an almost identical recording site in the same subject, was good reproducibility achieved. Such a wide and unpredictable variation in results would suggest great caution is needed when comparing traces obtained using a transtympanic technique which precludes a view of the electrode tip.