Abstract P4-01-05: Cell free DNA analysis identifies actionable ERBB2 amplifications in patients with HER2 equivocal breast cancer

Background:

Determination of ERBB2 (HER2) expression or amplification informs eligibility of HER2-targeted therapies. ASCO and NCCN guidelines recommend evaluation of HER2 status on primary invasive breast cancers and on a metastatic site if stage IV, where possible, as treatment is based on the status of the metastasis. Reassessment of HER2 status should also be considered in patients with disease recurrence as initially HER2-negative tumors may acquire HER2 amplification at progression. HER2 status can be complicated by equivocal results from in situ hybridization (ISH) and/or immunohistochemistry (IHC). Clarification requires reflex testing on the same tissue specimen or repeat testing on a new specimen, however some patients' tissue status remains equivocal. Furthermore, metastases to bone, lung, or brain may be difficult to re-biopsy or of low DNA quality. Rapid and non-invasive blood-based cell-free DNA (cfDNA) NGS may facilitate identification of HER2 targetable disease in advanced breast cancer.

Methods:

We assessed the frequency of ERBB2 amplification detectable by a blood-based cell-free DNA (cfDNA) assay among patients with metastatic breast cancer with equivocal HER2 results in tissue. cfDNA samples were ordered as part of routine clinical care using an assay validated for the detection of copy number amplification in ERBB2 (tests run between 03/2014-04/2017 by Guardant Health, Redwood City, CA). Submitted pathology reports were reviewed for HER2 status which was categorized as positive, negative, or equivocal based on the interpretation issued by the reading pathologist at the time the test was ordered. Patients were included if they had an equivocal result on IHC and/or ISH unless both assays were performed on the same specimen and one provided a definitive negative or positive HER2 result. Additionally, 4 patients with equivocal IHC or ISH results were excluded as biopsy of another tumor site revealed a positive HER2 result around the same time as the equivocal test. For the 349 patients with multiple cfDNA samples, the earliest pathology report was referenced.

Results:

Tissue HER2 status was available for 1,853 unique patients (98.8% female, median age at testing was 58y, range 26-91y). 141 patients (7.6%) had equivocal HER2 results in tissue; 99 by IHC alone, 14 by ISH alone, and 28 were equivocal by both assays. Among these, 126 patients (89.4%) had at least one sample with ctDNA detected. 12/126 (9.5%) had amplification of ERBB2 detected in at least one cfDNA sample. Samples were drawn a median of 267 days after tissue collection (range 4 days – 11.5 years). Frequency of ERBB2 amplification was similar regardless of time between tissue and blood collection but was higher among patients with ISH results alone (4/14, 36.4%) compared to those with IHC alone (6/89, 6.7%) or both assays (6/26, 7.6%; p=0.006).

Conclusion:

cfDNA testing identifies a significant number of patients with HER2-targetable advanced breast cancer whose tissue was HER2 equivocal. cfDNA testing may supplement tissue-based methods to help clarify HER2 status in metastatic disease as well as identify patients who may acquire HER2 amplification subsequent to their initial biopsy.

Citation Format: Rich TA, Raymond VM, Ahn ER, Banks KC, Brufsky A, Lee C, Lippman M, Pluard TJ, Schwab RB, Lanman RB. Cell free DNA analysis identifies actionable ERBB2 amplifications in patients with HER2 equivocal breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-01-05.

Abstract OT2-07-02: Trastuzumab deruxtecan (DS-8201a) vs investigator's choice of treatment in subjects with HER2-positive, unresectable and/or metastatic breast cancer who previously received T-DM1: A randomized, phase 3 study

Background: There is no uniform standard of care for HER2-positive breast cancer (BC) after disease progression on ado-trastuzumab emtansine (T-DM1). DS-8201a is a novel HER2-targeted antibody-drug conjugate (ADC) with a humanized HER2 antibody attached to a topoisomerase I inhibitor payload by a cleavable peptide-based linker, and with a drug-to-antibody ratio of 7 to 8. It is designed with the goal of improving critical attributes of an ADC. In an ongoing phase 1 trial, DS-8201a showed promising antitumor activity in HER2-positive BC previously treated with T-DM1 (confirmed objective response rate [ORR] of 54.5%; April 2018 data cutoff; Iwata et al, ASCO 2018). Based on preliminary results from the phase 1 trial, DS-8201a received FDA breakthrough therapy and fast track designations for metastatic BC that progressed after prior treatment with T-DM1. The pivotal, phase 2 DESTINY-BREAST01 trial in this population with HER2-positive BC who received prior T-DM1 is ongoing (Baselga et al, ASCO 2018).

Study Description: This multicenter, open-label, phase 3 trial will assess the efficacy and safety of DS-8201a in subjects with HER2-positive (IHC 3+ or IHC 2+/ISH+; confirmed by centralized testing) unresectable and/or metastatic BC whose disease progressed on or after T-DM1 (NCT03523585, DESTINY-BREAST02). Approximately 600 subjects will be randomized (2:1) to DS-8201a or investigator's choice of treatment (trastuzumab plus capecitabine or lapatinib plus capecitabine). Randomization is stratified by hormone receptor status, prior pertuzumab treatment, and history of visceral disease. DS-8201a (5.4 mg/kg) will be administered IV once every 3 weeks. Progression free survival (PFS) based on blinded, independent central review using RECIST v1.1 criteria is primary efficacy endpoint; overall survival (OS) is the key secondary endpoint. Other secondary efficacy endpoints are ORR, duration of response, clinical benefit rate, and PFS based on investigator assessment. Safety assessments include serious and treatment-emergent adverse events, physical examinations, vital signs, and clinical laboratory parameters. Health-related quality of life will also be measured. The primary analysis for PFS will occur when approximately 372 PFS events have been observed; providing 90% power to detect a hazard ratio of 0.70 in PFS (a 43% improvement in median PFS from 3.3 months with investigator's choice to 4.7 months with DS-8201a) with a 1-sided alpha of 0.025. An interim OS analysis is planned at the time of the PFS analysis. Final OS analysis will occur when approximately 428 OS events have been observed. Long-term follow-up will continue after the primary analysis every 3 months until death, withdrawal of consent, loss to follow-up, or study closure. Efficacy analyses will include all randomized subjects, and safety analyses will include all randomized subjects who received ≥1 dose of study treatment. The study will enroll subjects from approximately 160 sites including in North and South America, Europe, and Asia. For further information on this trial, contact Fabrice André at FABRICE.ANDRE@gustaveroussy.fr or visit clinicaltrials.gov.

Citation Format: André F, Shahidi J, Lee C, Wang K, Krop IE. Trastuzumab deruxtecan (DS-8201a) vs investigator's choice of treatment in subjects with HER2-positive, unresectable and/or metastatic breast cancer who previously received T-DM1: A randomized, phase 3 study [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr OT2-07-02.

Abstract P1-15-02: Withdrawn

This abstract was withdrawn by the authors.

Citation Format: Schwab R, Clark A, Yau C, Wolf D, Chien AJ, Majure M, Ewing C, Wallace A, Roesch E, Helsten T, Forero A, Stringer-Reasor E, Vaklavas C, Nanda R, Jaskowiak N, Boughey J, Haddad T, Han H, Lee C, Albain K, Isaacs C, Elias A, Ellis E, Shah P, Lang J, Lu J, Tripathy D, Kemmer K, Yee D, Haley B, Korde L, Edmiston K, Northfelt D, Viscusi R, Khan Q, I-SPY 2 Consortium, Symmans WF, Perlmutter J, Hylton N, Rugo H, Melisko M, Wilson A, Singhrao R, Asare S, van't Veer L, DeMichele A, Berry D, Esserman L. Withdrawn [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P1-15-02.

Effects of lysophospholipids on short-term production, nitrogen utilization, and rumen fermentation and bacterial population in lactating dairy cows

An experiment was conducted to examine effects of supplemental lysophospholipids (LPL) in dairy cows. Eight ruminally cannulated lactating Holstein cows were used in a replicated 4 × 4 Latin square design. Dietary treatments were (1) a dairy ration [CON; 55% forage and 45% concentrate on a dry matter (DM) basis], (2) a positive control diet supplemented with monensin (MON; 16 mg/kg in dietary DM; Elanco Animal Health, Greenfield, IN], (3) a control diet supplemented with low LPL (0.05% of dietary DM; Lipidol Ultra, Easy Bio Inc., Seoul, South Korea), and (4) a control diet supplemented with high LPL (0.075% of dietary DM). Experimental periods were 21 d with 14-d diet adaptation and 7-d sample collection. Daily intake and milk yield were measured and rumen contents were collected for fermentation characteristics and bacterial population. Spot urine and fecal samples (8 samples/cow per period) were collected to determine nutrient digestibility and dietary N utilization. All data were analyzed using the MIXED procedure of SAS (SAS Institute Inc., Cary, NC; group and cow within group were random effects and treatments, time, and their interaction were fixed effects). Preplanned contrasts were made to determine effect of MON versus CON, effect of LPL versus MON, and linear effect of increasing LPL. In the current study, responses to MON generally agreed with effects of monensin observed in the literature (increased milk yield and feed efficiency but decreased milk fat content). Supplementation of LPL to the diet did not alter DM intake but linearly increased milk yield, resulting in increases in feed efficiency (milk yield/DM intake) and milk protein and fat yields. However, total-tract digestibility of DM and organic matter tended to be lower (60.9 vs. 62.2% and 61.8 vs. 63.1%, respectively) for LPL compared with CON. Linear increases in milk N secretion and decreases in urinary N excretion were observed with increasing LPL in the diet. A slight decrease in acetate proportion in the rumen for LPL was found. Relative to MON, very few bacteria in the rumen were affected with increasing LPL. In conclusion, LPL is a potential feed additive that can increase milk yield and components and dietary N utilization. However, more studies with large numbers of animals are needed to confirm the effect of LPL on production. Similar positive effects on production were observed between LPL and MON, but individual mechanisms were likely different according to ruminal fermentation characteristics. Further studies are needed to explore the mode of action of LPL in dairy cows.

Cochlear compound action potentials from high-level tone bursts originate from wide cochlear regions that are offset toward the most sensitive cochlear region

Little is known about the spatial origins of auditory nerve (AN) compound action potentials (CAPs) evoked by moderate to intense sounds. We studied the spatial origins of AN CAPs evoked by 2- to 16-kHz tone bursts at several sound levels by slowly injecting kainic acid solution into the cochlear apex of anesthetized guinea pigs. As the solution flowed from apex to base, it sequentially reduced CAP responses from low- to high-frequency cochlear regions. The times at which CAPs were reduced, combined with the cochlear location traversed by the solution at that time, showed the cochlear origin of the removed CAP component. For low-level tone bursts, the CAP origin along the cochlea was centered at the characteristic frequency (CF). As sound level increased, the CAP center shifted basally for low-frequency tone bursts but apically for high-frequency tone bursts. The apical shift was surprising because it is opposite the shift expected from AN tuning curve and basilar membrane motion asymmetries. For almost all high-level tone bursts, CAP spatial origins extended over 2 octaves along the cochlea. Surprisingly, CAPs evoked by high-level low-frequency (including 2 kHz) tone bursts showed little CAP contribution from CF regions ≤ 2 kHz. Our results can be mostly explained by spectral splatter from the tone-burst rise times, excitation in AN tuning-curve "tails," and asynchronous AN responses to high-level energy ≤ 2 kHz. This is the first time CAP origins have been identified by a spatially specific technique. Our results show the need for revising the interpretation of the cochlear origins of high-level CAPs-ABR wave 1. NEW & NOTEWORTHY Cochlear compound action potentials (CAPs) and auditory brain stem responses (ABRs) are routinely used in laboratories and clinics. They are typically interpreted as arising from the cochlear region tuned to the stimulus frequency. However, as sound level is increased, the cochlear origins of CAPs from tone bursts of all frequencies become very wide and their centers shift toward the most sensitive cochlear region. The standard interpretation of CAPs and ABRs from moderate to intense stimuli needs revision.

A review of environmental enrichment for laying hens during rearing in relation to their behavioral and physiological development

Globally, laying hen production systems are a focus of concern for animal welfare. Recently, the impacts of rearing environments have attracted attention, particularly with the trend toward more complex production systems including aviaries, furnished cages, barn, and free-range. Enriching the rearing environments with physical, sensory, and stimulatory additions can optimize the bird's development but commercial-scale research is limited. In this review, "enrichment" is defined as anything additional added to the bird's environment including structurally complex rearing systems. The impacts of enrichments on visual development, neurobehavioral development, auditory stimulation, skeletal development, immune function, behavioral development of fear and pecking, and specifically pullets destined for free-range systems are summarized and areas for future research identified. Visual enrichment and auditory stimulation may enhance neural development but specific mechanisms of impact and suitable commercial enrichments still need elucidating. Enrichments that target left/right brain hemispheres/behavioral traits may prepare birds for specific types of adult housing environments (caged, indoor, outdoor). Similarly, structural enrichments are needed to optimize skeletal development depending on the adult layer system, but specific physiological processes resulting from different types of exercise are poorly understood. Stimulating appropriate pecking behavior from hatch is critical but producers will need to adapt to different flock preferences to provide enrichments that are utilized by each rearing group. Enrichments have potential to enhance immune function through the application of mild stressors that promote adaptability, and this same principle applies to free-range pullets destined for variable outdoor environments. Complex rearing systems may have multiple benefits, including reducing fear, that improve the transition to the layer facility. Overall, there is a need to commercially validate positive impacts of cost-effective enrichments on bird behavior and physiology.

New mesh-type phantoms and their dosimetric applications, including emergencies

Committee 2 of the International Commission on Radiological Protection (ICRP) has constructed mesh-type adult reference computational phantoms by converting the voxel-type ICRP Publication 110 adult reference computational phantoms to a high-quality mesh format, and adding those tissues that were below the image resolution of the voxel phantoms and therefore not included in the Publication 110 phantoms. The new mesh phantoms include all the necessary source and target tissues for effective dose calculations, including the 8-40-µm-thick target layers of the alimentary and respiratory tract organs, thereby obviating the need for supplemental organ-specific stylised models (e.g. respiratory airways, alimentary tract organ walls and stem cell layers, lens of the eye, and skin basal layer). To see the impact of the new mesh-type reference phantoms, dose coefficients for some selected external and internal exposures were calculated and compared with the current reference values in ICRP Publications 116 and 133, which were calculated by employing the Publication 110 phantoms and the supplemental stylised models. The new mesh phantoms were also used to calculate dose coefficients for industrial radiography sources near the body, which can be used to estimate the organ doses of the worker who is accidentally exposed by an industrial radiography source; in these calculations, the mesh phantoms were deformed to reflect the size of the worker, and also to evaluate the effect of posture on dose coefficients.

The ASOS Surgical Risk Calculator: development and validation of a tool for identifying African surgical patients at risk of severe postoperative complications

BACKGROUND

The African Surgical Outcomes Study (ASOS) showed that surgical patients in Africa have a mortality twice the global average. Existing risk assessment tools are not valid for use in this population because the pattern of risk for poor outcomes differs from high-income countries. The objective of this study was to derive and validate a simple, preoperative risk stratification tool to identify African surgical patients at risk for in-hospital postoperative mortality and severe complications.

METHODS

ASOS was a 7-day prospective cohort study of adult patients undergoing surgery in Africa. The ASOS Surgical Risk Calculator was constructed with a multivariable logistic regression model for the outcome of in-hospital mortality and severe postoperative complications. The following preoperative risk factors were entered into the model; age, sex, smoking status, ASA physical status, preoperative chronic comorbid conditions, indication for surgery, urgency, severity, and type of surgery.

RESULTS

The model was derived from 8799 patients from 168 African hospitals. The composite outcome of severe postoperative complications and death occurred in 423/8799 (4.8%) patients. The ASOS Surgical Risk Calculator includes the following risk factors: age, ASA physical status, indication for surgery, urgency, severity, and type of surgery. The model showed good discrimination with an area under the receiver operating characteristic curve of 0.805 and good calibration with c-statistic corrected for optimism of 0.784.

CONCLUSIONS

This simple preoperative risk calculator could be used to identify high-risk surgical patients in African hospitals and facilitate increased postoperative surveillance.

CLINICAL TRIAL REGISTRATION

NCT03044899.

Examination of the Rare Labial Talon Cusp on Human Anterior Teeth

The labial talon cusp, a triangular ridge of enamel near the midline of anterior teeth, has been observed in archaeological remains and modern dental patients. The purpose of our report is to describe new cases in order to provide better estimates of its frequency, symmetry, teeth involved, and geographic occurrence. This research was initiated after a labial talon cusp was found in a Caddo cranium curated in the Texas Archaeological Research Lab at the University of Texas at Austin. Subsequently, we identified additional examples resulting in the total of eight new cases presented here. Five cases were identified in the Native American Pima dental casts from the A. A. Dahlberg collection at Arizona State University. Two of the Pima cases were found in a systematic analysis of 1,835 dental casts for a population frequency of 0.11%. Additional cases were identified in Ainu and Anasazi skeletal material. Including these new finds, 15 cases of labial talon cusp are now known including Native Americans, African Americans, Japanese, Australians, and Europeans. Six cases are maxillary and nine are mandibular. Known maxillary cases are unilateral, while 55.6% of the mandibular cases are bilateral. All anterior teeth appear to be affected, but there is no recorded instance of an affected mandibular canine.