The efficacy and safety of macitentan in Fontan-palliated patients: results of the 52-week randomised, placebo-controlled RUBATO trial

Background

The clinical utility and long-term effects of endothelin receptor antagonists (ERAs) in Fontan-palliated patients remain unclear and there are currently no approved therapies. A decline in peak VO2 between consecutive cardiopulmonary exercise tests (CPETs) is highly prognostic for death or transplant in adult Fontan patients, hence its use as a primary endpoint in clinical trials of ERAs in patients with Fontan circulation.

Purpose

The RUBATO trial aimed to assess the efficacy and safety of macitentan, an endothelin receptor antagonist, in Fontan-palliated patients over 52 weeks.

Methods

In the multicentre, double-blind, randomised, placebo-controlled, phase 3 RUBATO trial, Fontan-palliated patients were randomised 1:1 to macitentan 10 mg once-daily or placebo for 52 weeks. Eligible patients were aged ≥12 years, in New York Heart Association functional class II or III, had no limitations for CPET (including no pacemakers), had undergone lateral tunnel or extracardiac conduit Fontan (total cavopulmonary connection) >1 year before screening and showed no signs of Fontan failure or clinical deterioration within 3 months before screening. Primary efficacy endpoint was change in peak VO2 from baseline to week 16. Secondary endpoints were change in peak VO2 from baseline over 52 weeks and change in mean count per minute of daily physical activity from baseline to week 16 as measured by an accelerometer. Adverse events were also assessed.

Results

137 patients were randomised to macitentan (n=68) or placebo (n=69). 92.7% of patients completed 52 weeks of double-blind treatment: 7 and 3 patients prematurely discontinued study treatment in macitentan and placebo arms, respectively. Patient baseline characteristics are shown in Table 1. At week 16, the mean (SD) change from baseline in peak VO2 was –0.16 (2.86) with macitentan vs –0.67 (2.66) mL/kg/min with placebo (median unbiased estimate of the difference between macitentan and placebo: 0.62 mL/kg/min [99% repeated confidence interval –0.62; 1.85], p=0.1930). No treatment effect was observed in the two secondary endpoints (Table 2): mean (SD) count per minute of daily physical activity decreased from baseline to week 16 by 3.02 (92.44) with macitentan and by 14.34 (117.56) with placebo (p=0.4512). The most common AEs were headache (10.3% vs 8.7% on placebo), nasopharyngitis (5.9% vs 4.3%), and pyrexia (5.9% vs 4.3%). AEs leading to treatment discontinuation were reported in 3 (4.4%) and 1 (1.4%) of macitentan and placebo patients.

Conclusion

The 52-week RUBATO trial provides an important addition to data on the clinical utility of ERAs in Fontan-palliated patients. The primary efficacy endpoint was not met and no treatment effect was observed for the two secondary endpoints. Macitentan was well tolerated; safety findings were consistent with the known safety profile of macitentan 10 mg.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Actelion Pharmaceuticals Ltd., a Janssen pharmaceutical company of Johnson & Johnson.

Modeling Active Non-Markovian Oscillations

Modeling noisy oscillations of active systems is one of the current challenges in physics and biology. Because the physical mechanisms of such processes are often difficult to identify, we propose a linear stochastic model driven by a non-Markovian bistable noise that is capable of generating self-sustained periodic oscillation. We derive analytical predictions for most relevant dynamical and thermodynamic properties of the model. This minimal model turns out to describe accurately bistablelike oscillatory motion of hair bundles in bullfrog sacculus, extracted from experimental data. Based on and in agreement with these data, we estimate the power required to sustain such active oscillations to be of the order of 100  k_{B}T per oscillation cycle.

Corona-specific health literacy: a longitudinal study in the German-speaking part of Switzerland

Background

The COVID-19 pandemic is accompanied by an infodemic, i.e. a flood of conflicting infor-mation through numerous channels and mis-/disinformation. To cope with these challenges and to make sound health-decisions, people need skills that enable them to access, under-stand, appraise, and use health-related information, i.e. adequate health literacy (HL). Thus, the present study investigates how people in the German-speaking part of Switzerland handle with Corona-specific information, what their difficulties are and what potential improvement measures could be.

Methods

Three representative samples of 1'000 individuals each were interviewed online in early sum-mer, autumn and winter 2020 using a modified version of the HLS-EU-Q16 questionnaire. Da-ta were analyzed using descriptive methods and an index for Corona-specific HL was built.

Results

In early summer, 55% of the German-speaking Swiss population reported adequate Corona-specific HL, with a tendency to increase with the duration of the pandemic (autumn: 62%; winter: 63%). Nonetheless, a great proportion reported difficulties, especially with assessing the trustworthiness of information from the media. With the progress of the pandemic, partici-pants felt less informed and the proportion of (very) poorly informed increased from 8% in early summer to 16% in winter 2020.

Conclusions

Participants often found it difficult to assess the trustworthiness of information on COVID-19 and to derive consequences for their own behavior. Hence, it is important that all relevant stakeholders such as health organizations, authorities and media support the population with tools to facilitate the use of health information and to empower them to take responsibility for their own health as well as for their community.

Key messages

People need adequate HL to handle the amount and complexity of COVID-19-related information. Relevant stakeholders need to take over responsibility to empower the population and to enhance their HL.

Aortic Z-scores in paediatric patients with marfan syndrome and other hereditary thoracic aortic diseases

Introduction

Marfan syndrome (MFS) and other hereditary thoracic aortic diseases (HTAD) are characterized by dilatation of the aorta caused by mutations in the FBN1-gene and other aortic genes. To prevent aortic dissection or rupture, patients are prophylactically treated by aortic surgery. Different z-scores of the aortic root are used for diagnosis and monitoring in paediatric patients.

Purpose

What are the differences between the various aortic Z-scores in their use for monitoring, assessing the severity of the aortic disease, and establishing the indication for surgery in this age group?

Methods

We retrospectively analyzed the diameters of aortic roots measured by echocardiography in 180 children and young adults (1 month to 25 years) with MFS and other HTADs presenting at our specialized outpatient clinic between January 2010 and August 2019. Thirteen patients underwent surgery during this period and 121 were monitored for a duration of one up to nine years. Five aortic z-scores were compared: Pettersen, Gautier, Cantinotti, Lopez, Boston. For evaluation of the severity of dilatation and indication for surgery, we used the last value before operation or the last follow-up value. For monitoring, we used the difference between the first and the last value. For comparison of the z-scores, values of the sinuses of Valsalva were analyzed. We investigated theoretic backgrounds and reference groups of each z-score.

Results

The z-score values differ significantly (p<0,001) for each score. The medians reach from 2.06 to 3.45, in operated patients 4.90 to 8.52, non-operated patients 1.86 to 3.31 (p<0,001). 93 aortic diameters to 136 were classified as dilatated (z-score ≥2). There were significant differences of almost all z-scores in the comparison with one another. During follow-up, the increase of the median z-score ranged from 0.11 to 0.24, in operated patients from 0.73 to 1.93, in non-operated patients from 0.02 to 0.21, respectively. The median monitoring time was 4.14 years and 2.93 years, for patients monitored for more than one year and all patients, respectively. In the operated subgroup, a weak correlation showed that the longer the monitoring time and the closer the surgery arrived, the faster the z-scores rose. Lopez, Boston and Cantinotti have higher values and label a value quicker than dilatated, but also reveal the severity of dilatation and the potential necessity of surgery.

Conclusions

Our data show that the various z-scores differ significantly. No z-score was superior regarding above-mentioned aspects, their differences in monitoring were small. However, it seems important to consistently use one same z-score. Expectedly, z-score values of each score were higher in the operated subgroup than in patients without surgery. However, there is no z-score value that determines a clear-cut indication for surgery.

Funding Acknowledgement

Type of funding sources: None.

First results of a regenerative transcatheter heart valve implant from autologous tissue in a long-term animal model

Background

The perfect heart valve replacement remains to be found regarding longevity, freedom of anticoagulation and availability in each size.

Purpose

Examination of a new technique for a regenerative, immunocompatible, transcatheter pulmonary valve implant from autologous pericardium was performed in an adult sheep model.

Methods

For each valve implant a pericardial patch was harvested by left antero-lateral mini-thoracotomy, placed on one of two slightly different shaped moulds either made of acrylic glass (AG) or printed in a 3D Printer (3D) and transferred into a container filled with a biological crosslinking agent at a non-toxic concentration to stabilize the given shape. After a median of 3 days (d) they were unpacked, sewn into a self-expandable nitinol stent with a diameter of 26 or 30mm and implanted via the jugular vein into pulmonary valve position of the same animal using a custom-made delivery system (1). Three groups (Gr) were planned: Gr 1) 4 animals with at least 6 d of crosslinking and AG mould; Gr 2) 5 animals with at least 3 d of crosslinking and AG mould; Gr 3) 6 animals with at least 3 d crosslinking and 3D mould. Follow ups (FU) were performed every 3 months (mo) evaluating valve function by intracardiac echocardiography (ICE) and cardiac MRI for up to 20.5 mo. All experiments were approved and conducted according to German federal law.

Results

In 11 of 13 animals minimally-invasive implantation was successful. One animal died because of ventricular fibrillation, in the other the implant dislocated into the right ventricle, so it had to be sacrificed. Direct post-implantation valve insufficiency was evaluated in 9 animals using ICE or angiography. In Gr 1 insufficiency was non-existent (n=2), in Gr 2 moderate or severe (n=2) and in Gr 3 non-existent or mild (n=5). Long term function as shown in figure 1 decreased rapidly in Gr 1 and 2 with median MRI regurgitation fractions (RF) in Gr 1 of 31% at 3 mo (n=3), 41% at 6 mo (n=3), 48% at 9 mo (n=2), 47% at 12 mo (n=3) and in Gr 2 of 43% at 3 and 54% at 6 mo (n=1) after implantation. Median RF in Gr 3 was small with 9% at 3 mo (n=4), 8% at 6 mo (n=3), 8% at 9 mo (n=3), 12% at 13 mo (n=3), 8% at 17 mo (n=2) and 20.5 mo (n=2). We never witnessed valve stenosis in any group at any point in time.

Conclusion

Gr 3 showed promising results regarding long time function of the implant which encourages further research with higher validity. The reason for failing of Gr 1 and 2 remains a topic of discussion. Regardless, valuable experience was gained in crafting and conducting the implantation of this new regenerative heart valve implant.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): EXIST research transfer program of the federal ministry of education and research

Circulatory efficiency in patients with severe aortic valve stenosis before and after aortic valve replacement

BACKGROUND

Circulatory efficiency reflects the ratio between total left ventricular work and the work required for maintaining cardiovascular circulation. The effect of severe aortic valve stenosis (AS) and aortic valve replacement (AVR) on left ventricular/circulatory mechanical power and efficiency is not yet fully understood. We aimed to quantify left ventricular (LV) efficiency in patients with severe AS before and after surgical AVR.

METHODS

Circulatory efficiency was computed from cardiovascular magnetic resonance (CMR) imaging derived volumetric data, echocardiographic and clinical data in patients with severe AS (n = 41) before and 4 months after AVR and in age and sex-matched healthy subjects (n = 10).

RESULTS

In patients with AS circulatory efficiency was significantly decreased compared to healthy subjects (9 ± 3% vs 12 ± 2%; p = 0.004). There were significant negative correlations between circulatory efficiency and LV myocardial mass (r = - 0.591, p < 0.001), myocardial fibrosis volume (r = - 0.427, p = 0.015), end systolic volume (r = - 0.609, p < 0.001) and NT-proBNP (r = - 0.444, p = 0.009) and significant positive correlation between circulatory efficiency and LV ejection fraction (r = 0.704, p < 0.001). After AVR, circulatory efficiency increased significantly in the total cohort (9 ± 3 vs 13 ± 5%; p < 0.001). However, in 10/41 (24%) patients, circulatory efficiency remained below 10% after AVR and, thus, did not restore to normal values. These patients also showed less reduction in myocardial fibrosis volume compared to patients with restored circulatory efficiency after AVR.

CONCLUSION

In our cohort, circulatory efficiency is reduced in patients with severe AS. In 76% of cases, AVR leads to normalization of circulatory efficiency. However, in 24% of patients, circulatory efficiency remained below normal values even after successful AVR. In these patients also less regression of myocardial fibrosis volume was seen. Trial Registration clinicaltrials.gov NCT03172338, June 1, 2017, retrospectively registered.

Efficacy of Retreatment After Failed Direct-acting Antiviral Therapy in Patients With HCV Genotype 1-3 Infections

Hepatitis C virus infection is causing chronic liver disease, cirrhosis, and hepatocellular carcinoma. By combining direct-acting antivirals (DAAs), high sustained virologic response rates (SVRs) can be achieved. Resistance-associated substitutions (RASs) are commonly observed after DAA failure, and especially nonstructural protein 5A (NS5A) RASs may impact retreatment options.^1-3 Data on retreatment of DAA failure patients using first-generation DAAs are limited.^4-7 Recently, a second-generation protease- and NS5A-inhibitor plus sofosbuvir (voxilaprevir/velpatasvir/sofosbuvir [VOX/VEL/SOF]) was approved for retreatment after DAA failure.⁸ However, this and other second-generation regimens are not available in many resource-limited countries or are not reimbursed by regular insurance, and recommendations regarding the selection of retreatment regimens using first-generation DAAs are very important. This study aimed to analyze patients who were re-treated with first-generation DAAs after failure of a DAA combination therapy.

Short- and Long-term Outcome After Interventional VSD Closure: A Single-Center Experience in Pediatric and Adult Patients

Interventional closure of congenital ventricular septal defects (VSD) is recording a continuous rise in acceptance. Complete atrioventricular block (cAVB) and residual shunting are major concerns during follow-up, but long-term data for both are still limited. We retrospectively evaluated the outcome of patients with interventional VSD closure and focused on long-term results (> 1 year follow-up). Transcatheter VSD closures were performed between 1993 and 2015, in 149 patients requiring 155 procedures (104 perimembranous, 29 muscular, 19 residual post-surgical VSDs, and 3 with multiple defects). The following devices were used: 65 × Amplatzer™ Membranous VSD Occluder, 33 × Duct Occluder II, 27 × Muscular VSD Occluder, 3 × Duct Occluder I, 24 × PFM-Nit-Occlud®, and 3 × Rashkind-Occluder. The median age at time of implantation was 6.2 (0.01-66.1) years, median height 117 (49-188) cm, and median weight 20.9 (3.2-117) kg. Median follow-up time was 6.2 (1.1-21.3) years and closure rate was 86.2% at last follow-up. Complications resulting in device explantation include one case of cAVB with a Membranous VSD occluder 7 days after implantation and four cases due to residual shunt/malposition. Six (4%) deaths occurred during follow-up with only one procedural related death from a hybrid VSD closure. Overall, our reported results of interventional VSD closure show favorable outcomes with only one (0.7%) episode of cAVB. Interventional closure offers a good alternative to surgical closure and shows improved performance by using softer devices. However, prospective long-term data in the current era with different devices are still mandatory to assess the effectiveness and safety of this procedure.

Robotic-assisted partial nephrectomy (RAPN) and standardization of outcome reporting: a prospective, observational study on reaching the "Trifecta and Pentafecta"

Partial nephrectomy (PN) for small renal masses is common, but outcomes are not reported in a standard manner. Traditionally, parameters such as 90-day mortality, blood loss, transfusion rates, length of stay, nephrometry scoring and complications are published but their collective impact on warm ischemia time (WIT) and post-surgery GFR is rarely determined. Thus, our aim was to assess if “Trifecta” and “Pentafecta” outcomes could be used as useful surgical outcome markers. A prospective database of 252 Robotic-Assisted PN (RAPN) cases (2008–2019) was analysed. “Pentafecta” was defined as achievement of “Trifecta” (negative surgical margin, no postoperative complications and WIT of < 25 min) plus over 90% estimated GFR preservation and no CKD stage upgrading at 1 year. Binary logistic regression analysis was conducted to predict factors which may prevent achieving a Trifecta/Pentafecta. Median tumour size was 3 cm and mean WIT was 15 min. Positive surgical margins (PSM) occurred in 2 cases. Overall, the intra-operative complication rate was 7%. One recurrence conferred 5-year cancer-free survival of 97%. Trifecta outcome was achieved in 169 (67%) and Pentafecta in 141 (56%) of cases. At logistic regression analysis, intraoperative blood loss was the only factor to affect Trifecta achievement (p = 0.018). Advanced patient age negatively impacted Pentafecta achievement (p = 0.010). The Trifecta and Pentafecta outcomes are easily applicable to PN data, and offer an internationally comparable PN outcome, quality measure. We recommend applying this standardization to national data collection to improve the quality of reporting and ease of interpretation of surgeon/centres’ outcomes.

P3688Familial recurrent autoimmune myocarditis associated with a truncating nonsense mutation of the desmoplakin gene

Background

Arrhythmogenic cardiomyopathy (AC) is an important cause of ventricular arrhythmias in children and young adults. AC is associated with mutation of desmosomal proteins, however, cardiac disease penetrance is incomplete and the clinical course varies widely without recognizable exogenous or epi/genetic co-factors. Importantly, DSP mutation carriers may also display entirely non-cardiac e.g. dermatological phenotypes.

Methods and results

In two brothers with recurrent fulminant myocarditis, mutation screening of 218 cardiomyopathy-related genes identified a truncating mutation Arg1458* of desmoplakin (DSP). DSP immunhistology unexpectedly revealed complete loss (“knockout”) of DSP protein in endomyocardial biopsies (EMBs), but none of the histological anomalies of AC. Criteria for histological diagnosis of myocarditis were not either fulfilled, and cardiac MRI revealed no features associated with AC. Screening for infections was negative, there was no substance abuse, medication or vaccination. Possible disease triggers were competitive sport events. Myosin and troponin I autoantibodies were detected at titers up to 1:320.

We used allele-specific RT-PCR to distinguish if the patients' allele classified as “normal” was actually defective due to promotor mutation or epigenetic silencing. RT-PCRs were done on EMBs and peripheral blood mononuclear cells (PBMCs). In a cohort of dilated cardiomyopathy (DCM) patients we were able to detect DSP transcripts in both, PBMC and left-ventricular heart tissue. RNA sequencing of human PBMC subpopulations suggested that DSP transcription may be restricted to certain immune cell subtypes. RT-PCRs revealed that both Arg1458* carriers have a functional second DSP allele, indicating that their “DSP knockout” occurs at the protein level and may be due to protein instability and degradation within desmosomes.

We screened additional existing cohorts for such variants and identified stopgain variant Gln307Ter in a 37-yrs-old woman with ARVC. This patient's sister died from heart failure at the age of 39. In a 59-yrs-old female LVNC patient, stopgain variant Y1391X was identified. Here, family history was unclear, her brother probably died from coronary artery disease. In a 71-yrs-old female DCM patient with no family history, stopgain variant Tyr1512Ter was identified.

Conclusions

The described patients with DSP truncations strongly suggest the existence of additional genetic or exogenous modifiers driving pathogenesis either way. DSP defects may cause recurrent myocarditis, and mutation screening is advisable to enable early detection of high-risk patients with similar phenotypes. Our finding of complete myocardial DSP protein loss emphasizes that DNA sequencing may miss critical molecular disturbances. It is indispensable to also analyze transcriptome and protein level in the tissue actually affected in a patient in order to recognize his/her individual pathogenesis.

Pattern of Care and Outcomes of Adolescent and Young Adults with Lymphoma Treated in the Rhône-Alpes Region

Background: Management of adolescent and young adults (AYAs) cancer is very heterogeneous. In the case of lymphomas, outcomes are mostly favorable but there is still room for improvement. Design: We retrospectively collected the pattern of care of all institutional 13- to 25-year-old AYAs patients with classical Hodgkin lymphoma (HL) or non-Hodgkin lymphoma (NHL) diagnosed in the Rhône-Alpes region between the years 2000 and 2005. Management, including adherence to Clinical Practice Guidelines (CPGs), and long-term survival were analyzed by comparing adult units (AU) and pediatric units (PU). Results: 278 patients were included: 198 treated for HL (median age of 19 years), 80 treated for NHL (median age of 20 years). Among them, 74% were managed in AU and 26% in PU. The median time between diagnosis and starting treatment was significantly lower in PU than in AU. Sixty-five patients (23%) were included in clinical trials, mostly in AU. Five-year overall survival was 96% for HL [14 deaths, median follow-up 91 months (9-180)] and 90% for NHL [nine deaths, median follow-up 80 months (3-180)]. Secondary cancers occurred for 2% (n = 3) of HL patients and for none in NHL. Other major late complications included cardiovascular accidents in two patients and fatal pulmonary fibrosis in one patient. Major differences in chemotherapy and radiotherapy use are emphasized. Global management conformed to CPGs by 56%. Conclusions: Important differences between adult and pediatric management were reported, without any impact on survival. A few patients can be included in clinical trials: Homogeneity in management could improve specific care for AYAs.

A multivariate Th17 metagene for prognostic stratification in T cell non-inflamed triple negative breast cancer

A diversity of T helper (Th) subsets (Th1, Th2, Th17) has been identified in the human tumor microenvironment. In breast cancer, the role of Th subsets remains controversial, and a systematic study integrating Th subset diversity, T cell inflammation, breast cancer molecular subtypes, and patient prognosis, is lacking. In primary untreated breast cancer samples, we analyzed 19 Th cytokines at the protein level. Eight were T cell-specific, and subsequently measured in 106 prospectively-collected untreated samples. The dominant Th cytokines across all breast cancer samples were IFN-γ and IL-2. Th2 cytokines (IL-4, IL-5, IL-13) were expressed at low levels and not associated with any breast cancer subtype. Th17 cytokines (IL-17A and IL-17F) were up-regulated in triple negative breast cancer (TNBC), specifically in T cell non-inflamed tumors. In order to get insight into prognosis, we exploited the METABRIC transcriptomic dataset. We derived Th1, Th2, and Th17 metagenes based on manually curated Th signatures, and found that a high Th17 metagene was of good prognosis in T cell non-inflamed TNBC. Multivariate Cox modeling selected the Nottingham Prognostic Index (NPI), Th2 and Th17 metagenes as additive predictors of breast cancer-specific survival, which defined novel and highly distinct prognostic groups within TNBC. Our results reveal that Th17 is a novel prognostic composite biomarker in T cell non-inflamed TNBC.

Integrating immune cell and tumor molecular diversity is an efficient strategy for prognostic stratification of cancer patients.

Abstract GS3-07: Clinical utility of circulating tumor cell count as a tool to chose between first line hormone therapy and chemotherapy for ER+ HER2- metastatic breast cancer: Results of the phase III STIC CTC trial

Background: In ER+ HER2- metastatic breast cancer (MBC) patients, the clinical choice between 1st line hormone therapy (HT, the recommended option) or chemotherapy (CT) is based on the absence of “visceral crisis” or adverse prognostic factors, with no proven/objective criteria. In that context, STIC CTC (NCT01710605) was set up as a strategy trial to test whether circulating tumor cells (CTC) count could help customize the choice between 1st line HT or CT.

Methods: For this multicenter phase 3 non-inferiority trial, the main inclusion criteria were: ER+ HER2- MBC with no prior therapy, PS≤2, no contra-indication to HT or CT and informed consent. The a priori treatment choice (HT or CT) and CTC count (CellSearch®) were obtained in all patients prior to randomization. Patients were randomized 1:1 between clinically-driven choice (CTC count not disclosed, HT or CT administered as decided a priori), or a CTC-driven choice (HT if &lt;5 CTC/7.5ml, CT if ≥5 CTC/7.5ml). The primary objective was treatment efficacy (PFS hazard ratio), non-inferiority being established if the upper bound of the PFS HR 2-sided 90%CI is ≤1.25; secondary objectives included subgroup analyses (CTC status, patient characteristics) and OS.

Results: 761 MBC patients were randomized between 02/2012 and 08/2016. Baseline characteristics: 7.8% of patients had a PS=2, 24.1% had a de novo metastatic disease; 63.3% received prior adjuvant HT and 49.9% prior adjuvant CT; 31.3% had ≥3 metastatic sites. A priori treatments (HT or CT) and CTC count (&lt; or ≥5 CTC/7.5ml) were well balanced between the two arms. After randomization, in the clinically-driven arm, N=267 (72.4%) patients received HT and N=102 (27.6%) CT (as decided a priori). In the CTC-driven arm: (1) the a priori choice of HT was confirmed by a low CTC count in N=181 (67.5%) of patients, while N=87 (32.5%) were switched to CT due to a high CTC count; (2) the a priori choice of CT was confirmed by high CTC count in only N=48 (48%) patients, while N=52 (52%) were switched to HT. The primary endpoint was met, PFS being not inferior in the CTC-driven arm (HR=0.98, 90%CI=[0.84–1.13]). Analyses focusing on discordant subgroups showed that for patients with a priori choice of HT but with high CTC count (leading to a switch to CT in the CTC-arm), PFS was significantly longer in the CTC-driven arm than in the standard arm (HR=0.67, 95%CI=[0.49–0.92]; p=0.01), with a non-significant trend toward longer OS (HR=0.68, 95%CI=[0.44–1.07]; p=0.09). Inversely, for patients with a priori choice of CT but with low CTC count (i.e. de-escalation to HT in the CTC arm), PFS was not statistically different between the two arms.

Conclusion: This trial demonstrates the clinical utility of CTC count as an objective decision tool when considering 1st line therapy in ER+ HER2- MBC. In most patients, CTC count did confirm the a priori clinical choice; however, trial results show that in discrepant cases, CTC count may be trusted for either escalating (i.e. considering CT in patients if high CTC count) or de-escalating (i.e. considering HT in patients if low CTC count) 1st line therapy.

Funding: French National Cancer Institute; Menarini Silicon Biosystems.

Citation Format: Bidard F-C, Jacot W, Dureau S, Brain E, Bachelot T, Bourgeois H, Goncalves A, Ladoire S, Naman H, Dalenc F, Gligorov J, Espie M, Levy C, Ferrero J-M, Loirat D, Cottu P, Dieras V, Simondi C, Berger F, Alix-Panabieres C, Pierga J-Y. Clinical utility of circulating tumor cell count as a tool to chose between first line hormone therapy and chemotherapy for ER+ HER2- metastatic breast cancer: Results of the phase III STIC CTC trial [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 GS3-07.

Abstract PD2-03: Circulating tumor DNA (ctDNA) and circulating tumor cells (CTC) predictive value in HER2 negative metastatic breast cancer patients treated with first line weekly paclitaxel and bevacizumab: Results of a prospective cohort from the French Breast Cancer InterGroup Unicancer (UCBG): COMET study

Background: Increased levels of CTC and a persistent elevated level after just one cycle of chemotherapy are very strong and independent markers of worse progression-free survival (PFS) and overall survival (OS) in patients (pts) with metastatic breast cancer (MBC) (Bidard et al, Lancet Oncol 2014). ctDNA can be used to detect mutation associated with resistance to treatment. It has also been shown that dynamic changes in ctDNA levels closely reflect changes in tumor burden. We prospectively monitored CTC and ctDNA early variations during first line chemotherapy for MBC.

Patients & methods: The French cohort COMET is a prospective study including first line HER2 negative patients (pts) receiving weekly paclitaxel and bevacizumab according to EMA approved combination. The aim of this cohort is to evaluate clinical, biological and radiological parameters associated with pts outcome (CTC, serum markers, ctDNA, pharmacogenomic polymorphisms, metabolomic parameters, visceral fat, serum estradiol level and quality of life). We present here the first planned analysis on pts evaluated for CTC (CellSearch) and ctDNA using targeted sequencing (Roche SeqCap technology) of a panel of 46 genes and 8 promoters, using unique molecular identifiers to increase ctDNA detection sensitivity. Blood samples were obtained at baseline (BL) and before the second cycle of chemotherapy (C2).

Results: From 09/2012 to 5/2014, 218 pts were included in this substudy. Median age was 55 years and 22% of pts had triple negative BC. At BL, 70% of pts had ≥1 detectable CTC per 7.5 ml of blood (median 4 CTC, range 1- 30,000) and 37% at C2. With a threshold of ≥5 CTC, 47% of pts were positive at BL and 22% at C2. For ctDNA, out of the first 141 pts analyzed, 105 had at least one somatic mutation detected in plasma (74%). The average number of mutations per pt was 2.7 and most commonly mutated genes were TP53 and PIK3CA. ESR1 was found mutated in 9% of all cases and restricted to the ER+ subgroup. Median Allelic Frequency was 10% (range 0.6-83%). Only 33% of pts had detectable ctDNA at C2. At BL, CTC and ctDNA levels were correlated (r=0.46, p&lt;0.0001). Despite no complete overlap, 11% of pts had no CTC nor ctDNA detected. Median follow-up was 53 months and median OS was 32 months. Increased level of CTC and ctDNA were significantly associated with decreased PFS and OS. At C2, ≥5 CTC or still detectable ctDNA were strong markers of reduced OS: HR 4.6 (CI95 3.1-7) and HR 3.2 (CI95 1.8 – 5.5), respectively (both p&lt; 0.0001). At multivariate analysis for PFS, detectable ctDNA at C2 and triple negative status were the only significant prognostic factors. None of serum marker level at BL or their early variations had prognostic value.

Conclusion: This is the largest prospective cohort assessing the respective prognostic values of early CTC and ctDNA changes in homogenously treated first line MBC patients. Analysis of mutations profile variations and comparison with primary tumor and metastasis biopsies are ongoing and may reveal early mechanisms of resistance.

Citation Format: Pierga J-Y, Silveira A, Lorgis V, Tanguy M-L, Tredan O, Dubot C, Jacot W, Goncalves A, Debled M, Levy C, Ferrero J-M, Jouannaud C, Luporsi E, Mouret-Reynier M-A, Dalenc F, Lemonnier J, Berger F, Proudon C, Bidard F-C. Circulating tumor DNA (ctDNA) and circulating tumor cells (CTC) predictive value in HER2 negative metastatic breast cancer patients treated with first line weekly paclitaxel and bevacizumab: Results of a prospective cohort from the French Breast Cancer InterGroup Unicancer (UCBG): COMET 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 PD2-03.