Baseline Mutations and ctDNA Dynamics as Prognostic and Predictive Factors in ER-Positive/HER2-Negative Metastatic Breast Cancer Patients

PURPOSE

Prognostic and predictive biomarkers to cyclin-dependent kinases 4 and 6 inhibitors are lacking. Circulating tumor DNA (ctDNA) can be used to profile these patients and dynamic changes in ctDNA could be an early predictor of treatment efficacy. Here, we conducted plasma ctDNA profiling in patients from the PEARL trial comparing palbociclib+fulvestrant versus capecitabine to investigate associations between baseline genomic landscape and on-treatment ctDNA dynamics with treatment efficacy.

EXPERIMENTAL DESIGN

Correlative blood samples were collected at baseline [cycle 1-day 1 (C1D1)] and prior to treatment [cycle 1-day 15 (C1D15)]. Plasma ctDNA was sequenced with a custom error-corrected capture panel, with both univariate and multivariate Cox models used for treatment efficacy associations. A prespecified methodology measuring ctDNA changes in clonal mutations between C1D1 and C1D15 was used for the on-treatment ctDNA dynamic model.

RESULTS

201 patients were profiled at baseline, with ctDNA detection associated with worse progression-free survival (PFS)/overall survival (OS). Detectable TP53 mutation showed worse PFS and OS in both treatment arms, even after restricting population to baseline ctDNA detection. ESR1 mutations were associated with worse OS overall, which was lost when restricting population to baseline ctDNA detection. PIK3CA mutations confer worse OS only to patients on the palbociclib+fulvestrant treatment arm. ctDNA dynamics analysis (n = 120) showed higher ctDNA suppression in the capecitabine arm. Patients without ctDNA suppression showed worse PFS in both treatment arms.

CONCLUSIONS

We show impaired survival irrespective of endocrine or chemotherapy-based treatments for patients with hormone receptor-positive/HER2-negative metastatic breast cancer harboring plasma TP53 mutations. Early ctDNA suppression may provide treatment efficacy predictions. Further validation to fully demonstrate clinical utility of ctDNA dynamics is warranted.

CCNE1 and PLK1 mediates resistance to palbociclib in HR+/HER2- metastatic breast cancer

PURPOSE

In HR+/HER2- metastatic breast cancer (MBC) is imperative to identify patients who respond poorly to CDK4/6i and to discover therapeutic targets to reverse this resistance. Non-luminal breast cancer subtype and high levels of CCNE1 are candidate biomarkers in this setting but further validation is needed.

EXPERIMENTAL DESIGN

We performed mRNA gene expression profiling and correlation with progression-free-survival (PFS) on 455 tumor samples included in the phase III PEARL study, that assigned HR+/HER2- MBC patients to receive palbociclib+ET vs capecitabine. ER+/HER2- breast cancer cell lines were used to generate and characterize resistance to palbociclib+ET.

RESULTS

Non-luminal subtype was more prevalent in metastatic (14%) than in primary tumor samples (4%). Patients with non-luminal tumors had median PFS of 2.4months (m) with palbociclib+ET and 9.3m with capecitabine; HR:4.16, adjusted p-value<0.0001. Tumors with high CCNE1 expression (above median) had also worse median PFS with palbociclib+ET (6.2m) than with capecitabine (9.3m); HR:1.55, adjusted p-value=0.0036. In patients refractory to palbociclib+ET (PFS in the lower quartile) we found higher levels of Polo Like Kinase 1 (PLK1). In an independent data set (PALOMA3), tumors with high PLK1 show worse median PFS than those with low PLK1 expression under palbociclib+ET treatment. In ER+/HER2- cell line models we show that PLK1 inhibition reverses resistance to palbociclib+ET.

CONCLUSIONS

We confirm the association of non-luminal subtype and CCNE1 with resistance to CDK4/6i+ET in HR+ MBC. High levels of PLK1 mRNA identify patients with poor response to palbociclib, suggesting PLK1 could also play a role in the setting of resistance to CDK4/6i.

CCNE1 mRNA and cyclin E1 protein expression as predictive biomarkers for efficacy of palbociclib plus fulvestrant versus capecitabine in the phase III PEARL study

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Background: The randomized PEARL trial found no superiority of palbociclib plus endocrine therapy over capecitabine in patients (pts) with metastatic HR-positive, HER2-negative breast cancer resistant to prior aromatase inhibitors (Martin M, Ann Oncol 2020). Gene expression analysis showed high CCNE1 mRNA ( CCNE1) conferring relative resistance to palbociclib in the PALOMA-3 trial (Turner N, JCO 2019), but further validation is needed. Cyclin E1 protein (cyclin E1) expression in this context has not been studied in randomized trials. We explored CCNE1 and cyclin E1 as predictive biomarkers in tumor samples from the PEARL study. Methods: Formalin-fixed paraffin-embeded tumor samples were retrieved from pts enrolled in PEARL cohort 2 (palbociclib (PAL) + fulvestrant (FUL) vs capecitabine (CAPE)). We measured CCNE1 using the HTG EdgeSeq Oncology Biomarker Panel (HTG Molecular Diagnostics). Cyclin E1 immunohistochemistry (IHC) staining was performed using specific mouse monoclonal antibody HE12 (Abcam) and scored as percentage of invasive nuclei stained (0-100%). CCNE1 and cyclin E1 correlations were explored using Pearson coefficients. Cox regression models were used for progression free-survival (PFS) analyses using expression levels split by median, to define high ( > median values) vs. low expression. Site of disease and prior chemotherapy were used as confounders in multivariate models. Results: Analyses were conducted in 219 pts (47% receiving PAL + FUL and 53% CAPE) with available tumors, with the analysed patients representative of the overall study. Most samples were from the archival primary (72%), obtained > 5 years before this analysisº (74%). CCNE1 and cyclin E1 were only moderately correlated (r = 0.5). Median CCNE1 was higher in metastatic vs primary (7.37 vs 6.94, p < 0.01), and in luminal B and non-luminal subtypes compared to luminal A (p < 0.001). In patients with high CCNE1 expression, median PFS on CAPE was 10.35 and PAL + FUL was 5.68 (HR = 1.63, 95% CI 1.02-2.59, p = 0.042). In patients with low CCNE1 expression, median PFS on CAPE was 9.43 and PAL + FUL was 8.97 (adjusted HR = 0.93, 95% CI 0.59-1.48, p = 0.762, interaction p = 0.072). Median cyclin E1 protein was higher in luminal B and non-luminal subtypes compared to luminal A (p < 0.01). Cyclin E1 protein expression was not predictive of treatment effect (high cyclin E1 expression CAPE vs PAL + FUL HR = 1.17, low cyclin E1 expression CAPE vs PAL + FUL HR = 1.21, interaction p = 0.977). Conclusions: High tumor CCNE1 mRNA expression identified patients with relative resistance to palbociclib plus fulvestrant, validating prior observations although without statistical significance for interaction. Assessment of Cyclin E1 protein expression did not show predictive value. Investigation treatments to enhance CDK4/6 inhibitor efficacy in tumors with high CCNE1 expression is warranted. Clinical trial information: NCT02028507 .

Prognostic and predictive value of ESR1 mutations in postmenopausal metastatic breast cancer (MBC) patients (pts) resistant to aromatase inhibitors (AI), treated with palbociclib (PAL) in combination with endocrine therapy (ET) or capecitabine (CAP) in the PEARL study

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Background: Prior retrospective data has shown ESR1 mutation is an acquired resistant mechanism to AI. However, little is known about ist prognostic and predictive value to endocrine-based therapy and chemotherapy. PEARL study compared PAL+ET vs CAP in AI resistant patients. Here we wxplored prospectively the ESR1 mutational status based on updated PFS and OS. Methods: PEARL is a phase 3 study with 2 subsequent cohorts: cohort 1 with 296 pts randomized to PAL+Exemestane (EXE) vs CAP and cohort 2 with 305 pts randomized to PAL+ Fulvestran (FUL) vs CAP. ESR1 hotspot mutations were analyzed in circulating free DNA at baseline by digital PCR. Cox regresion analysis for PFS and OS were performed. Adjusted hazard ratios (aHR) and interaction test between treatment and ESR1 status were calculated. Results: ESR1 mutational status was assessed in 557 pts, 91% and 94% treated with CAP and PAL+ET, respectively; 164 (29%) had ESR1 mutations. Characteristics between ESR1 wild-type (WT) and mutated pts were balanced except for ECOG, prior sensitivity to ET, treatment line, prior AI for metastatic disease and time from first metastatic diagnosis to randomization. Median follow-up was 22.5 months (m). Median PFS was 9.6 vs. 7.5 m (HR: 1.06 [0.88 - 1.28], p = 0.522) and median OS was 30.2 vs 30.3 (HR: 0.99 [0.78 - 1.26] p = 0.934), for CAP vs. PAL+ET, respectively. No interaction was seen between treatment arm and ESR1 status either for PFS (p = 0.538) or OS (p = 0.957). Conclusions: In luminal MBC, ESR1-mutated pts had poorer OS than ESR1-WT pts regardless of treatment received. Clinical trial information: NCT02028507 . [Table: see text]

First results of a prospective registry in unresectable locally advanced or metastatic breast cancer patients: GEICAM/2014-03 (RegistEM)

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Background: In Spain there is limited prospective data for unresectable locally advanced breast cancer (ULABC) or metastatic breast cancer (MBC) patients (pts) treated as per clinical practice. RegistEM study will provide epidemiological, pathological and clinical data, including treatments given for different disease stages. Understanding the real distribution of the different BC subtypes is the primary objective. Methods: This is a non-interventional cohort study enrolling approximately 1,400 pts with advanced disease diagnosed from January 2016 to December 2018, either after recurrence or as first diagnosis, in 38 Spanish sites. Biological samples (primary tumor, metastatic lesions, blood) are currently being collected. In this first analysis, we include 489 pts who met study criteria before October 31, 2017. All data are described in two subgroups: on the most recent tumor lesion or on the primary breast tumor. Results: At first diagnosis, 67.9%, 31.5% and 0.6% of pts had early BC (EBC), MBC and ULABC, respectively. In the total analysis population, median age at diagnosis of advanced disease was 59.6 years, most of pts were white (98.2%), female (99.4%) and postmenopausal (70%). Family history of BC and ovarian cancer was reported in 5.7% pts. In ~390 pts BC clinical subtypes distribution was luminal B(HER2-)-like (~55%), luminal B(HER2+)-like (~16%), luminal A-like or triple negative (TN) (~10% each) and HER2 enriched-like (~8%). Median time to recurrence (years) in EBC pts was: luminal A-like 5.8, luminal B(HER2-)-like 5.1, luminal B(HER2+)-like 3.9, HER2 enriched-like 2.7 and TN 1.7. Bone (59%), visceral (58%) and lymph node (27%) lesions were the most frequent metastatic locations. The two most frequent therapies in first line consisted in: endocrine therapy (ET) (47%) and ET+biological therapy (BT) (29%) for luminal A-like; ET (32%) and ET+BT (32%) for luminal B(HER2-)-like; chemotherapy (CT)+ET+BT (43%) and CT+BT (24%) for luminal B(HER2+)-like; CT+BT (68%) and CT (16%) for HER2 enriched-like; CT (59%) and CT+BT (34%) for TN. Conclusions: These first data confirm that luminal B (HER2-)-like subtype is the most predominant in MBC.

Randomized phase III study of adjuvant chemotherapy for high-risk, node-negative breast cancer (BC) comparing FAC with FAC followed by weekly paclitaxel: First efficacy analysis of the GEICAM/2003-02 trial

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Background: Adjuvant weekly paclitaxel (wP) sequential to anthracyclines improves the outcome of operable node-positive BC patients (pts) [Sparano NEJM 2008, Martin BCRT 2009]; however, most BC pts are currently node-negative at diagnosis. The role of wP in these pts is not well established yet. Methods: Pts aged 18-70, with T1-T3/N0 operable BC and at least one high-risk St Gallen 1998 criteria (size >2 cm, hormone-receptor [HR] negative, grade 2/3, age <35 years,) were eligible. HER2+ pts were allowed, after 792 entered the trial, the study was amended to exclude them. Pts were stratified by site, menopausal status, nodal status diagnostic method (sentinel-node biopsy versus lymphadenectomy) and HR status and randomized to receive FAC x6 (500/50/500 mg/m2 every 3w) or FAC x4→wP x8 (paclitaxel 100 mg/m2 weekly). The primary endpoint was DFS. The trial was designed to detect an absolute 5-y DFS increase of 5% (80% FAC, 85% FAC→wP); a sample size of 1812 evaluable patients (906 per arm) was required to detect this difference (α=0.05, β= 80%). Assuming a drop-out rate of 6%, 1929 pts were required. The first analysis of DFS was planned when a median follow-up of 5 years was reached. Results: Between September 2003 and October 2008, 1925 pts (FAC 974, FAC→wP 951) were randomized. Patient characteristics were well balanced between arms, median age was 50, 73% of pts were HR positive and 9% HER2 positive. 97% of pts with FAC and 85% of pts with FAC→wP completed all treatment as planned. The median dose intensity was 98% with FACx6, 99% with FACx4 and 98% with wP. The most frequent grade 3-4 toxicities (>3% in either arm) with FAC vs FAC→wP were neutropenia (25% vs 22%) with 4% vs 3% of febrile neutropenia, fatigue (3% vs 8%), sensory neuropathy (0 vs 5%), and vomiting (4% in each arm). After a median follow-up of 5.3 years, the proportion of patients disease free is 93% and 90% with FAC→wP and FAC (HR for relapse 0.732, 95% CI: 0.542 to 0.990; log-rank p-value=0.0423). Conclusions: For pts with high-risk node-negative BC, adjuvant FAC→wP was associated with a small but significant improvement in DFS compared with FAC, with manageable toxicity.

Cross-sectional observational study to describe the clinicopathological and biological characteristics and the management of patients with HER2+ metastatic breast cancer who experienced complete or partial remission or disease stabilization during at least 3 years: LongHer study

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Background: Trastuzumab has shown an improvement in survival outcomes among patients with HER2+ metastatic breast cancer (MBC). Identification of factors and tumor molecular profiles that may predict long-term remission has become a key-issue. Methods: Multicenter, observational, cross-sectional study. Data were collected from women with HER2+ MBC treated with a trastuzumab-based regimen that experienced CR, PR or SD during at least 3 years. FFPE samples(at least 70% tumor cells)for Microarray Analysis were obtained. L2 Boosting for classification with classical Akaike Information criterion based on the binomial log-likelihood for stopping the boosting iterations algorithm was applied to RNA expression data, to identify variables related to clinical information. Predictive models of long term response were built using a Binary Logistic Regression with the Fisher's scoring. Results: 103 patients.Median age: 58(51-68) years. Metastatic disease diagnosed after a median of 24.7(1.8-51.9) months since primary diagnosis. Predominant type: ductal carcinoma(91.9%) and 59% histological grade III. Hormonal status: Progesterone receptor positive 39.2% and estrogen receptor positive 41.2%. Most common metastatic sites: multiple locations(31.4%), lung(23.5%), bone(14.7%) and liver(13.7%). Overexpression of HER2 assessed by IHC in 98.1% of patients, 91.1% were HER2+(3+) and 18.4% had FISH+ HER2 status. Tumor was positive for p53 (>30%) and Ki67(>20%) in 47.3% and 73.6%. Surgery: 87.4% of patients, 77.5% radical mastectomy. Surgery of metastases was performed on 16.8%. Trastuzumab used in combination in 88.3% with a median number of cycles of 35.5(7.0-46). 68.9% of patients achieved a CR, 20.4% PR and 10.7% had SD, during an overall median time of 55 (43-79) months. 4 patients discontinued trastuzumab due to toxicity. Conclusions: Trastuzumab may provide a substantial long-term survival benefit with a manageable safety profile in these patients. Molecular analysis will be presented in the forthcoming Congress.

The effect of body mass index on overall and disease-free survival in node-positive breast cancer patients treated with docetaxel and doxorubicin-containing adjuvant chemotherapy: the experience of the BIG 02-98 trial

BACKGROUND

Obesity has been shown to be an indicator of poor prognosis for patients with primary breast cancer (BC) regardless of the use of adjuvant systemic therapy.

PATIENTS AND METHODS

This is a retrospective analysis of 2,887 node-positive BC patients enrolled in the BIG 02-98 adjuvant study, a randomised phase III trial whose primary objective was to evaluate disease-free survival (DFS) by adding docetaxel to doxorubicin-based chemotherapy. In the current analysis, the effect of body mass index (BMI) on DFS and overall survival (OS) was assessed. BMI was obtained before the first cycle of chemotherapy. Obesity was defined as a BMI >or= 30 kg/m2.

RESULTS

In total, 547 (19%) patients were obese at baseline, while 2,340 (81%) patients were non-obese. Estimated 5-year OS was 87.5% for non-obese and 82.9% for obese patients (HR 1.34; P = 0.013). Estimated 5-years DFS was 75.9% for nonobese and 70.0% for obese patients (HR 1.20; P = 0.041). Ina multivariate model, obesity remained an independent prognostic factor for OS and DFS.

CONCLUSIONS

In this study,obesity was associated with poorer outcome in node-positive BC patients. Given the increasing prevalence of obesity worldwide, more research on improving the treatment of obese BC patients is needed.

Determination of salicylate in blood serum by flow injection with immobilized salicylate hydroxylase

A flow injection (FI) enzymatic system, based on the use of immobilized salicylate hydroxylase in glass beads, was developed for the determination of salicylate. Salicylate hydroxylase and nicotinamide adenine dinucleotide (NADH) are used to convert salicylate to catechol. The reaction of catechol with 4-aminophenol at high pH yields a colored product which is detected spectrophotometrically at 565 nm. Ten samples of human serum containing from 5.0 x 10(-4) to 5.0 x 10(-3) mol/L added salicylate were analyzed and the recovery was determined. Eight additional serum samples containing salicylate were analyzed by the Trinder test and the proposed method. The results obtained with the 2 methods showed good agreement by the statistical Student's t-test. The relative precision of the method is about 3.4% (RSD of the mean recovery). Considering the lowest concentration analyzed, the quantitative limit of detection is about 0.2 x 10(-5) mol/L (3 x SD). The volume of the sample used was 150 microL. The proposed method was also used to analyze medicines containing acetylsalicylic acid. The results were statistically compared with those obtained through the U.S. Pharmacopoeia procedure and showed excellent agreement.

Sagittal synostosis: results of surgical treatment in 210 patients

From 1977 to 1996, 210 patients suffering from scaphocephaly, have been operated on in our institutions. The surgical technique depended on the patients age. Single wide sagittal synostectomy was performed in 155 babies aged less than 3 months, obtaining good cosmetic results. Patients older than 3 months needed more complex and aggressive procedures to achieve similar results. The conclusions is that sagittal suturectomy is the proper treatment in younger patients under 3 months of age, and that a greater effort must be made to diagnose and treat these patients early.

Effect of porosity and environment on the mechanical behavior of acrylic bone cement modified with acrylonitrile-butadiene-styrene particles: part II. Fatigue crack propagation

The aim of this study was to investigate the effect of adding an elastomeric second phase, acrylonitrile-butadiene-styrene, on the fatigue crack propagation behavior of poly(methyl methacrylate) bone cement. Moreover, the influence of porosity and environmental conditions was studied. When comparing the plain cement to the modified cement, a decrease in the crack propagation rate was observed at between 1 and 2 orders of magnitude. The storage in a physiological environment (saline solution at 37 degrees C) also caused a decrease in the crack propagation rate of about 2 orders of magnitude for the plain and modified cement prepared in air or under a vacuum. Porosity did not have any noticeable effect on the fatigue crack propagation behavior of the cement.

Effect of porosity and environment on the mechanical behavior of acrylic bone cement modified with acrylonitrile-butadiene-styrene particles: I. Fracture toughness

The elastomeric copolymer acrylonitrile-butadiene-styrene (ABS) was added to a conventional acrylic bone cement matrix. The results obtained show that although strength and stiffness decreased with an increasing second phase volume fraction, ductility and toughness both increased. The crack propagation became stable for specimens containing over a 5% volume fraction of the second phase. The fracture toughness increased up to 60% when the amount of ABS reached 20% (v/v). For larger amounts linear elastic fracture mechanics techniques could not be used properly. The effects of porosity and environmental conditions on the mechanical behavior were also studied. The mechanisms that control the fracture process were investigated by means of scanning electron microscopy.

Precocious puberty and hypothalamic hamartoma with total recovery after surgical treatment. Case report

✓ A hypothalamic hamartoma was found in an 18-month-old boy who presented with mild precocious puberty. Following partial removal of the tumor, there was prompt improvement in clinical signs and plasma endocrine levels. Two years after surgery the patient was completely normal. The pathological examination of the excised tumor showed normal glial tissue.