Abstract P4-13-03: Elacestrant (RAD1901) demonstrates anti-tumor activity in models resistant to CDK4/6 inhibitors

Background: Approximately 75% of all breast cancers diagnosed are estrogen receptor-positive (ER+) and currently approved endocrine therapies rely heavily on blocking of the ER signaling pathway. In recent years, the combination of an endocrine agent with other targeted agents have been evaluated to address endocrine resistance and improve progression-free survival (PFS). Recently, it was demonstrated that the addition of a cyclin-dependent kinase 4/6 (CDK4/6) inhibitor to an endocrine agent roughly doubles PFS, leading to the approval and use of certain CDK4/6 inhibitors in combination with either aromatase inhibitors in the first-line metastatic setting or in combination with the selective estrogen receptor degrader (SERD), fulvestrant, in the second-line metastatic setting. While combining CDK4/6 inhibitors and endocrine therapy can result in significantly increased PFS, patients eventually progressed on these combinations, and to date, there is no cure for patients with advanced metastatic ER+ breast cancer. Given the increased use of CDK4/6 inhibitors in the ER+ breast cancer treatment paradigm, it will be important to understand how treatment resistance to CDK4/6 inhibitors manifests in order to optimize therapeutic strategies to target this patient population. We have previously described elacestrant (RAD1901), a novel and orally bioavailable SERD, as an inhibitor of ER+ breast cancer growth in in vitro models and in in vivo patient-derived xenograft (PDX) models. Importantly, elacestrant inhibited the growth of PDX models that were derived from heavily pretreated patients, models harboring mutations in ESR1, and models insensitive to standard of care endocrine therapies. Given these results, we hypothesized that elacestrant would have anti-tumor activity in a CDK4/6 inhibitor-resistant setting. Herein, we describe elacestrant activity in multiple in vitro and in vivo models of CDK4/6 inhibitor resistance in both wild-type and mutant ESR1 backgrounds.

Methods: In vitro models of estrogen-independent ER+ breast cancer, harboring either wild-type or mutant ER, were exposed to increasing concentrations of approved CDK4/6 inhibitors: palbociclib, ribociclib, or abemaciclib. ER expression/signaling, changes in cell cycle mediators, and the effects of elacestrant and other SERDs were examined in these representative models.

Results: Despite prolonged exposure to CDK4/6 inhibitors, the resistant cell lines retained ER, ER signaling, and importantly, ER-driven proliferation. Elacestrant induced dose-dependent growth inhibition in CDK4/6 inhibitor-resistant cells, and this effect was independent of the CDK4/6 inhibitor used to generate resistance. Elacestrant also demonstrated in vivo tumor growth inhibition of CDK4/6 inhibitor-resistant ER+ PDX models.

Conclusions: Our preclinical data demonstrate that elacestrant is a SERD that can inhibit tumor growth in a CDK4/6 inhibitor-resistant setting and provides rationale for examining elacestrant in patients that have progressed on a combination of endocrine therapy with a CDK4/6 inhibitor.

Citation Format: Patel H, Tao N, Arlt H, Bihani T. Elacestrant (RAD1901) demonstrates anti-tumor activity in models resistant to CDK4/6 inhibitors [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 P4-13-03.

Abstract P6-20-08: Anti-tumor activity of elacestrant (RAD1901) in models harboring ESR1 mutations resistant to standard of care therapies

Background: Estrogen receptor positive (ER+) breast cancers make up approximately 75% of all breast cancers diagnosed and ER, a protein encoded by the ESR1 gene, plays a major role in the initiation, growth and survival of these cancers. Current targeted therapies inhibit the ER pathway by either blocking the synthesis of the natural ligand of ER, estradiol, (aromatase inhibitors (AI)), or by antagonizing and/or degrading the receptor (selective estrogen receptor modulators (SERMs) and selective estrogen receptor degraders (SERDs)). AIs are used in both the adjuvant and metastatic setting and recent clinical reports have shown that 20-50% of patients that had received AI therapy had detectable mutations in the ER ligand binding domain (ER-LBD). Two frequently found point mutations in the ER-LBD, Y537S and D538G, have been shown to result in estradiol-independence and constitutive activation of ER, consistent with their ability to cause resistance to AIs. While the selection of ESR1 mutations post-AI has been demonstrated clinically, the clinical response of ESR1 mutant tumors to fulvestrant, an approved SERD, is not fully understood. Preclinical studies have suggested that ESR1 mutations can cause decreased binding and a corresponding decrease in potency of ER antagonists, including fulvestrant (SERD) and tamoxifen (SERM). Conversely, clinical data from the SoFEA, PALOMA-3, and FERGI trials suggested the presence of ESR1 mutations did not alter fulvestrant activity. The limited clinical data that exists, however, is based on retrospective study designs with relatively small data sets, making it difficult to accurately predict fulvestrant activity against specific mutations and the activity of fulvestrant against tumors that harbor multiple mutations. In fact, recent additional data from the PALOMA-3 trial suggests that the Y537S mutation, specifically, was selected out in clinical samples from patients treated with fulvestrant, more closely matching preclinical results. This suggests there may be certain contexts of ESR1 mutations where fulvestrant may have limited activity. It will be important to further understand the consequence of specific mutations and to utilize therapies that have activity against all ESR1 mutations. We have previously described elacestrant (RAD1901), a novel orally bioavailable SERD, that exhibited activity in multiple ER+ breast cancer models. Interestingly, elacestrant exhibited similar effects to fulvestrant in in vitro ESR1 mutant models, however, in some in vivo PDX models harboring the Y537S mutation elacestrant inhibited growth, while fulvestrant had limited activity. Here, we describe a more complete in vivo dataset describing elacestrant activity versus fulvestrant in multiple patient-derived xenograft (PDX) models harboring ESR1 mutations.

Methods: Multiple PDX models harboring natural mutations in ESR1 or genetically-engineered CRISPR models were used to assess the anti-tumor efficacy and the pharmacokinetic/pharmacodynamic properties of elacestrant and fulvestrant.

Results: Elacestrant significantly inhibited the growth of xenograft models harboring ESR1 mutations, including those harboring Y537S or D538G mutations and models that were insensitive to fulvestrant and tamoxifen.

Citation Format: Patel H, Tao N, Arlt H, Bihani T. Anti-tumor activity of elacestrant (RAD1901) in models harboring ESR1 mutations resistant to standard of care therapies [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 P6-20-08.

A rare presentation of angioedema with isolated retropharyngeal and supraglottic involvement

Angiotensin converting-enzyme (ACE) inhibitors are commonly prescribed drugs with multiple indications including congestive heart failure, hypertension, and diabetic nephropathy. ACE inhibitor induced angioedema is commonly seen across emergency departments and clinics, with transient swelling of lips, tongue, and other facial structures being the common presentation. Isolated airway obstruction as a result of pharyngeal and laryngeal swelling without facial swelling is a rare presentation. We present a case of a patient on lisinopril therapy for one year who experienced severe airway compromise without the classic symptoms of ACE inhibitor induced angioedema. He required emergent cricothyroidotomy to secure his airway, as fiberoptic laryngoscopy showed 90% obstruction and inability to visualize true vocal cords. His ACE inhibitor therapy was discontinued, and he was discharged home within a few days with no residual symptoms.

Mind the gap: 11 years of train-related injuries at the Royal London Hospital Major Trauma Centre

Introduction This study presents an extensive retrospective database of patients with polytrauma following train-related injuries and highlights the key lessons learnt in this rare clinical presentation. Materials and methods We retrospectively collected data from 127 patients who presented to Royal London Hospital after sustaining train related trauma. We analysed demographics, accident report data, aetiologies and clinical management interventions. All data were screened and injuries were mapped to various anatomical regions. The revised trauma score, injury severity score and new injury severity scores were used to quantify injury extent. Results Mean patient age was 41 years (range 16-81 years) with a 73% to 27% male to female ratio. Deliberate injuries occurred in 71% of patients, with accidental injury accounting for 29%. The mean new injury severity score was 26.48 (range 1-75), with the most common injuries sustained to the chest and the extremities. Pneumothorax, haemothorax or tension pneumothorax occurred in 44% of patients, with 11% suffering a flail chest injury. Traumatic amputations occurred in 33% of patients and 56% of patients required admission to intensive care. Total mortality rates were 19%, with 12% of patients dying at day 0 and 18% at day 7, respectively. Conclusions This study demonstrated the significant impact of train-related polytrauma and provided a comprehensive injury patterns. It was observed that deliberate polytrauma is related to psychiatric deliberate harm but there is no significant difference in the patterns of injuries between accidental and deliberately caused injuries. Overall injuries to the thorax and extremities were the most severe, demonstrating the highest mean injury scores.

Straight-to-test faecal tagging CT colonography for exclusion of colon cancer in symptomatic patients under the English 2-week-wait cancer investigation pathway: a service review

AIM

To present the initial 12 months of data of a straight-to-test (STT) computed tomography colonography (CTC) protocol as the first-line investigation for change in bowel habit (CIBH) and iron deficiency anaemia (IDA) in patients over 60 referred directly from primary care.

MATERIALS AND METHODS

In 12 months, 1,792 STT CTC for IDA and CIBH were performed. No colonoscopies were performed as the primary investigation in this cohort. Data from this cohort were gathered prospectively.

RESULTS

The colorectal cancer (CRC) detection rate was 4.9% and polyp detection rate was 13.5%. The CRC rate increased related to age (p=0.001), the CRC detection rate was 2.6% in patients aged 60-69 years, compared to 4.9%, 7.4%, and 11.4% in the 70-79, 80-89, and >90 years age groups. The CRC rate was higher in patients with IDA compared to CIBH (6.8% versus 3.9%, p=0.017). There were significantly more left-sided cancers (p=0.0165). Non-colonic cancers were found in 4.3% of patients and 6.8% had incidental findings that required further investigation and 11.9% had a new, potentially significant, incidental finding.

CONCLUSION

These results are comparable to colonoscopy in terms of diagnostic accuracy and similar to those of CTC in published multicentre trials. This exciting model of care within radiology enables earlier testing, reduces waiting times, with fewer outpatient appointments, and results in good clinician and patient satisfaction.

Differentiation of human male germ cells from Wharton's jelly-derived mesenchymal stem cells

Objective

Recapitulation of the spermatogenesis process in vitro is a tool for studying the biology of germ cells, and may lead to promising therapeutic strategies in the future. In this study, we attempted to transdifferentiate Wharton's jelly-derived mesenchymal stem cells (WJ-MSCs) into male germ cells using all-trans retinoic acid and Sertoli cell-conditioned medium.

Methods

Human WJ-MSCs were propagated by the explant culture method, and cells at the second passage were induced with differentiation medium containing all-trans retinoic acid for 2 weeks. Putative germ cells were cultured with Sertoli cell-conditioned medium at 36℃ for 3 more weeks.

Results

The gene expression profile was consistent with the stage-specific development of germ cells. The expression of Oct4 and Plzf (early germ cell markers) was diminished, while Stra8 (a premeiotic marker), Scp3 (a meiotic marker), and Acr and Prm1 (postmeiotic markers) were upregulated during the induction period. In morphological studies, approximately 5% of the cells were secondary spermatocytes that had completed two stages of acrosome formation (the Golgi phase and the cap phase). A few spermatid-like cells that had undergone the initial stage of tail formation were also noted.

Conclusion

Human WJ-MSCs can be transdifferentiated into more advanced stages of germ cells by a simple two-step induction protocol using retinoic acid and Sertoli cell-conditioned medium.

Knowledge, attitudes and awareness of the human papillomavirus amongst primary care practice nurses: an evaluation of current training in England

Background

The incorporation of Human papillomavirus (HPV) testing into the English cervical screening programme has been met with fear and anxiety. Healthcare professionals need to be adequately informed about HPV to help alleviate patient concerns. The aim of this study was to evaluate the HPV training provided to practice nurses (PNs) and determine their level of HPV knowledge.

Method

A web-based survey was distributed to 147 General Practice surgeries in the Leicester, Leicestershire and Rutland regions, between May and July 2015. The survey explored four broad areas; demographics/level of experience, HPV knowledge, attitudes towards the HPV vaccine and self-perceived adequacy of HPV knowledge.

Results

A total of 128 surveys were completed, with 94 complete responses. Overall awareness of basic HPV facts was adequate; however, detailed, and in some cases basic, knowledge was lacking. 9.6% failed to identify that HPV can cause cervical cancer and 62.8% believed that HPV requires treatment. Not all PNs felt adequately informed about HPV and a need to improve the provision of training was identified.

Conclusion

PNs play a key role in increasing public awareness of HPV and implementing cervical cancer screening. The provision of education to PNs needs to be a priority and current methods of training need to be re-evaluated.

A genome-wide association study for extremely high intelligence

We used a case-control genome-wide association (GWA) design with cases consisting of 1238 individuals from the top 0.0003 (~170 mean IQ) of the population distribution of intelligence and 8172 unselected population-based controls. The single-nucleotide polymorphism heritability for the extreme IQ trait was 0.33 (0.02), which is the highest so far for a cognitive phenotype, and significant genome-wide genetic correlations of 0.78 were observed with educational attainment and 0.86 with population IQ. Three variants in locus ADAM12 achieved genome-wide significance, although they did not replicate with published GWA analyses of normal-range IQ or educational attainment. A genome-wide polygenic score constructed from the GWA results accounted for 1.6% of the variance of intelligence in the normal range in an unselected sample of 3414 individuals, which is comparable to the variance explained by GWA studies of intelligence with substantially larger sample sizes. The gene family plexins, members of which are mutated in several monogenic neurodevelopmental disorders, was significantly enriched for associations with high IQ. This study shows the utility of extreme trait selection for genetic study of intelligence and suggests that extremely high intelligence is continuous genetically with normal-range intelligence in the population.

Cyclin D mediates tolerance of genome-doubling in cancers with functional p53

Background

Aneuploidy and chromosomal instability (CIN) are common features of human malignancy that fuel genetic heterogeneity. Although tolerance to tetraploidization, an intermediate state that further exacerbates CIN, is frequently mediated by TP53 dysfunction, we find that some genome-doubled tumours retain wild-type TP53. We sought to understand how tetraploid cells with a functional p53/p21-axis tolerate genome-doubling events.

Methods

We performed quantitative proteomics in a diploid/tetraploid pair within a system of multiple independently derived TP53 wild-type tetraploid clones arising spontaneously from a diploid progenitor. We characterized adapted and acute tetraploidization in a variety of flow cytometry and biochemical assays and tested our findings against human tumours through bioinformatics analysis of the TCGA dataset.

Results

Cyclin D1 was found to be specifically overexpressed in early but not late passage tetraploid clones, and this overexpression was sufficient to promote tolerance to spontaneous and pharmacologically induced tetraploidy. We provide evidence that this role extends to D-type cyclins and their overexpression confers specific proliferative advantage to tetraploid cells. We demonstrate that tetraploid clones exhibit elevated levels of functional p53 and p21 but override the p53/p21 checkpoint by elevated expression of cyclin D1, via a stoichiometry-dependent and CDK activity-independent mechanism. Tetraploid cells do not exhibit increased sensitivity to abemaciclib, suggesting that cyclin D-overexpressing tumours might not be specifically amenable to treatment with CDK4/6 inhibitors.

Conclusions

Our study suggests that D-type cyclin overexpression is an acute event, permissive for rapid adaptation to a genome-doubled state in TP53 wild-type tumours and that its overexpression is dispensable in later stages of tumour progression.

Multi-polygenic score approach to trait prediction

A primary goal of polygenic scores, which aggregate the effects of thousands of trait-associated DNA variants discovered in genome-wide association studies (GWASs), is to estimate individual-specific genetic propensities and predict outcomes. This is typically achieved using a single polygenic score, but here we use a multi-polygenic score (MPS) approach to increase predictive power by exploiting the joint power of multiple discovery GWASs, without assumptions about the relationships among predictors. We used summary statistics of 81 well-powered GWASs of cognitive, medical and anthropometric traits to predict three core developmental outcomes in our independent target sample: educational achievement, body mass index (BMI) and general cognitive ability. We used regularized regression with repeated cross-validation to select from and estimate contributions of 81 polygenic scores in a UK representative sample of 6710 unrelated adolescents. The MPS approach predicted 10.9% variance in educational achievement, 4.8% in general cognitive ability and 5.4% in BMI in an independent test set, predicting 1.1%, 1.1%, and 1.6% more variance than the best single-score predictions. As other relevant GWA analyses are reported, they can be incorporated in MPS models to maximize phenotype prediction. The MPS approach should be useful in research with modest sample sizes to investigate developmental, multivariate and gene-environment interplay issues and, eventually, in clinical settings to predict and prevent problems using personalized interventions.

Postoperative monitoring of the free jejunal flap: use of colour duplex and systematic review of available techniques

Introduction The free jejunal flap represents the gold standard for circumferential defects in upper digestive tract reconstruction. It is a technically demanding procedure with significant failure rates. Unrecognised failure leads to flap necrosis and potentially fatal sequelae, including sepsis and carotid artery bleed. Despite these catastrophic consequences, however, there remains no consensus on an optimum method for postoperative flap monitoring. Our unit has pioneered the use of external colour duplex ultrasound to monitor flap vascularity. We describe this technique and systematically review other published monitoring systems. Materials and methods A patient underwent oesophageal reconstruction using a jejunal free flap. Monitoring commenced immediately via external application of a colour duplex probe over the flap's vascular pedicle to facilitate flow volume assessment. Further bi-daily assessments were successfully used to monitor the postoperative viability of the flap. The systematic review was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Results Six alternative monitoring techniques were identified: exteriorised jejunal segment, implantable Doppler probe, watch window, microdialysis, microendoscopy and reflectance photoplethysmography. Discussion Exteriorised jejunal segment and implantable Doppler probe are most commonly described, yet both are associated with high false positive rates, which is particularly significant in a patient demographic facing increased general anaesthetic risk. Most other techniques remain experimental. External colour Doppler ultrasound provides the surgeon with immediate reassurance following the reconstruction, requires minimal training to use, and eliminates the need for revisional procedures. Conclusion Our initial experience suggests that external colour Doppler ultrasound has exciting potential as an efficient and noninvasive technique for monitoring the free jejunal flap.

Transvascular Retrieval of a Catheter Remnant from the Peripheral Vein of a Preterm Neonate

We report the first case of transvenous removal of a peripheral inserted central catheter (PICC) fragment embolized to a peripheral vein in a 32-week gestational age 1450 g infant. The technical aspect of this alternative method to surgery is discussed.

Abstract P1-10-05: ICEC0942, a new oral selective inhibitor of the cell cycle and transcriptional regulator CDK7 for the treatment of estrogen receptor positive and negative breast cancer

CDK7 is remarkable as a key regulator of both cell cycle progression and gene expression. CDK7 promotes cell cycle progression by phosphorylating cell cycle CDKs in the T-loop, thus stimulating their activities. Additionally, phosphorylation of RNA polymerase II (PolII) by CDK7 is required for transcription initiation. Deregulation of cell cycle and transcription processes is common to most cancer types, so CDK7 inhibitors offer considerable promise as cancer therapeutics.

We previously reported the identification of the first selective CDK7 inhibitor, BS-181, and demonstrated its ability to inhibit breast cancer cell growth in vitro and in vivo (Ali et al 2009 Cancer Res). Screening of more than one thousand analogues has allowed development of a clinical candidate CDK7 inhibitor, named ICEC0942. ICEC0942 selectively inhibits CDK7 with an IC50 of 40nM. In vitro analyses reveal that ICEC0942 inhibits hormone receptor positive and triple-negative breast cancer cell lines, with GI50 values ranging between 0.2-0.3 μM. Growth inhibition is accompanied by inhibition of CDK7 targets, including CDK1, CDK2 and PolII phosphorylation. In xenograft studies using several cancer cell lines, the drug shows substantial anti-tumor effects, with a notable lack of toxicity at efficacious doses. In the combination setting with tamoxifen, ICEC0942 completely blocks growth of ER-positive tumor xenografts, indicative of potential for co-treatment with hormonal agents.

Extensive ADMET and PK/PD studies confirm the suitability of ICEC0942 as a cancer drug and have shown that ICEC0942 is orally bioavailable. Moreover, xenograft tumor studies have allowed definition of surrogate biomarkers of tumor response.

Taken together, our findings confirm CDK7 as an important drug target for ER-positive and -negative breast cancer and identify ICEC0942 as a prototype drug with utility as a single agent or in the combination setting. Our findings also point to the potential value of CDK7 inhibition by ICEC0942 in other cancer types that have characteristics of transcription factor addiction and/or cell cycle deregulation.

Development of ICEC0942 was made possible through funding by EPSRC, Cancer Research UK and Cancer Research Technologies.

Citation Format: Ali S, Patel H, Periyasamy M, Sava G, Bondke A, Slafer BW, Kroll SHB, Barbazanges M, Starkey R, Ottaviani S, Harrod A, Aboagye EO, Buluwela L, Fuchter MJ, Barrett AGM, Coombes RC. ICEC0942, a new oral selective inhibitor of the cell cycle and transcriptional regulator CDK7 for the treatment of estrogen receptor positive and negative breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P1-10-05.

Definitions, measurements and prevalence of fear of childbirth: a systematic review

Background

Fear of Childbirth (FOC) is a common problem affecting women’s health and wellbeing, and a common reason for requesting caesarean section. The aims of this review were to summarise published research on prevalence of FOC in childbearing women and how it is defined and measured during pregnancy and postpartum, and to search for useful measures of FOC, for research as well as for clinical settings.

Methods

Five bibliographic databases in March 2015 were searched for published research on FOC, using a protocol agreed a priori. The quality of selected studies was assessed independently by pairs of authors. Prevalence data, definitions and methods of measurement were extracted independently from each included study by pairs of authors. Finally, some of the country rates were combined and compared.

Results

In total, 12,188 citations were identified and screened by title and abstract; 11,698 were excluded and full-text of 490 assessed for analysis. Of these, 466 were excluded leaving 24 papers included in the review, presenting prevalence of FOC from nine countries in Europe, Australia, Canada and the United States. Various definitions and measurements of FOC were used. The most frequently-used scale was the W-DEQ with various cut-off points describing moderate, severe/intense and extreme/phobic fear. Different 3-, 4-, and 5/6 point scales and visual analogue scales were also used. Country rates (as measured by seven studies using W-DEQ with ≥85 cut-off point) varied from 6.3 to 14.8%, a significant difference (chi-square = 104.44, d.f. = 6, p < 0.0001).

Conclusions

Rates of severe FOC, measured in the same way, varied in different countries. Reasons why FOC might differ are unknown, and further research is necessary. Future studies on FOC should use the W-DEQ tool with a cut-off point of ≥85, or a more thoroughly tested version of the FOBS scale, or a three-point scale measurement of FOC using a single question as ‘Are you afraid about the birth?’ In this way, valid comparisons in research can be made. Moreover, validation of a clinical tool that is more focussed on FOC alone, and easier than the longer W-DEQ, for women to fill in and clinicians to administer, is required.

Electronic supplementary material

The online version of this article (10.1186/s12884-018-1659-7) contains supplementary material, which is available to authorized users.