Exemestane Research Articles

Methotrexate-Lactoferrin Targeted Exemestane Cubosomes for Synergistic Breast Cancer Therapy.

While the treatment regimen of certain types of breast cancer involves a combination of hormonal therapy and chemotherapy, the outcomes are limited due to the difference in the pharmacokinetics of both treatment agents that hinders their simultaneous and selective delivery to the cancer cells. Herein, we report a hybrid carrier system for the simultaneous targeted delivery of aromatase inhibitor exemestane (EXE) and methotrexate (MTX). EXE was physically loaded within liquid crystalline nanoparticles (LCNPs), while MTX was chemically conjugated to lactoferrin (Lf) by carbodiimide reaction. The anionic EXE-loaded LCNPs were then coated by the cationic MTX–Lf conjugate via electrostatic interactions. The Lf-targeted dual drug-loaded LCNPs exhibited a particle size of 143.6 ± 3.24 nm with a polydispersity index of 0.180. It showed excellent drug loading with an EXE encapsulation efficiency of 95% and an MTX conjugation efficiency of 33.33%. EXE and MTX showed synergistic effect against the MCF-7 breast cancer cell line with a combination index (CI) of 0.342. Furthermore, the Lf-targeted dual drug-loaded LCNPs demonstrated superior synergistic cytotoxic activity with a combination index (CI) of 0.242 and a dose reduction index (DRI) of 34.14 and 4.7 for EXE and MTX, respectively. Cellular uptake studies demonstrated higher cellular uptake of Lf-targeted LCNPs into MCF-7 cancer cells than non-targeted LCNPs after 4 and 24 h. Collectively, the targeted dual drug-loaded LCNPs are a promising candidate offering combinational hormonal therapy/chemotherapy for breast cancer.

Abstract P2-07-04: Analysis of host inflammatory and estrogen biomarkers in JAKEE: A phase II trial of the JAK inhibitor ruxolitinib in combination with exemestane for estrogen receptor-positive metastatic breast cancer

Abstract Background: Circulating IL-6, an activator of JAK/STAT signaling, is associated with poor outcomes and aromatase inhibitor (AI) resistance in hormone-receptor positive (HR+) metastatic breast cancer (MBC). We previously presented clinical outcomes of JAKEE, a single arm, phase II, Simon two-stage clinical trial that tested Ruxolitinib (Rux), an oral selective inhibitor of JAK1/2, and exemestane (EXE) in 25 participants (pts) with HR+ MBC that relapsed/progressed on non-steroidal AI (NSAI); specifically, the primary endpoint of safety was met, but there were no complete or partial responses and 6/25 (24%) achieved stable disease (SD) for ≥6 cycles. We investigated whether host circulating inflammatory markers, IL-6 genotypes, and estrogen levels were associated with differential response to therapy.Methods: Responders (R) were defined as having achieved SD≥6 cycles. Flow cytometry was performed on baseline and on-treatment peripheral blood samples to assess downstream CD3+ T-cell phosphoSTAT3 inhibition by Rux. Serum concentrations of C-reactive protein (CRP), IL-6, serum amyloid A (SAA), Estrone (E1) and Estradiol (E2) were measured at baseline and serially on treatment. Sanger sequencing was performed to assess for three functional variants of the IL-6 promoter: −572G>C (rs1800796), −597G>A (rs1800797), and −174G>C (rs1800795), with high-risk polymorphisms being -597G/G and/or -174G/G. Non-parametric median testing was employed to test for differences in circulating markers by response groups given non-normal distribution, with a two-sided alpha of 0.05.Results: The cohort was heavily pre-treated: 28% received ≥2 lines of chemotherapy for MBC and 20% had CNS disease at enrollment. Among 17/25 pts with samples for pharmacodynamic assessment, Rux exhibited a 25% median inhibition (range 0-77%) of phosphoSTAT3. There was no differential effect in R vs non-responders (NR) (median inhibition 20% vs 29%, p=0.15). Frequency of high-risk IL-6 genotypes and distribution of baseline serum CRP, IL-6, SAA, E1 and E2 are depicted in the table. 15/25 (60%) harbored a high-risk IL-6 promoter polymorphism, with no significant difference in frequency between R and NR (50% vs 63%, p=0.65). 19 pts had samples for inflammatory biomarker analysis. 16/19 had baseline CRP≥10mg/L. While median levels of baseline CRP, SAA, and IL-6 were above upper limit of normal, there was no difference between R and NR (table). The proportion of pts with baseline undetectable E1 and E2 were similar between R and NR (E1: 36.9% vs 33.3%, p=1.0, E2: 52.6% vs 50%, p=1.0); notably, a significantly lower proportion with high-risk IL-6 genotype had undetectable baseline E1 (20% vs 60%, p=0.041), while no difference was noted for baseline E2, nor in the % change in E1 or E2 levels from baseline to cycle 4 by responder status.Conclusions: The JAKEE cohort represents an inflamed population with elevated circulating inflammatory markers and a high proportion with high-risk IL-6 genotypes. Examination of host inflammatory markers, IL-6 genotypes and estrogen levels did not reveal a differential response to the combination of Rux and EXE in patients with HR+ MBC that had progressed on prior NSAI. At tolerable dosing, Rux exhibited only a modest inhibition of phosphoSTAT3. Further work is needed to optimize strategies for targeting inflammation and JAK/STAT signaling in HR+ MBC. IL-6 GenotypeFrequencyFrequency by ResponderSignificanceHigh-Risk -174G/G and/or -597G/G15/25 (60%)Non-responder12/19 (63.2%)Responder3/6 (50%)p-value0.56Pretreatment Inflammatory Biomarkers [Upper limit of normal]Median (Range)Median Level by Responder GroupSignificanceCRP [8mg/L]SAA [10mg/L]IL-6 [2pg/mL]24.0 (0.2-146.8)12.8 (2.8-162.5)4.2 (1.8-11.5)Non-responder23.219.84.5Responder24.7 12.42.7p-value0.510.150.15Baseline Estrogen BiomarkersMedian (Range)Non-responderResponderp-valueEstrone (E1) (pg/mL)Estradiol (E2) (pg/mL)79.5.0 (0.2-1039.0)0.2 (0.2-44.1)79.8 0.247.8 4.20.410.91 Citation Format: Igor Makhlin, Nicholas McAndrew, E. Paul Wileyto, Amy Clark, Robin Holmes, Lisa N Bottalico, Grace R Jeschke, Kevin R Fox, Susan M Domcheck, Jennifer M Matro, Angela R Bradbury, Natalie Shih, Michael D Feldman, Elizabeth O Hexner, Jacqueline F Bromberg, Angela DeMichele. Analysis of host inflammatory and estrogen biomarkers in JAKEE: A phase II trial of the JAK inhibitor ruxolitinib in combination with exemestane for estrogen receptor-positive metastatic breast cancer [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P2-07-04.

Safety and Efficacy of RAD001 (Everolimus) Administered Upon Relapse During or After Adjuvant Treatment in Post-menopausal Women With Hormone Receptor Positive, HER2/neu Negative Locally Advanced or Metastatic Breast Cancer (CRAD001JGR08 "MELPOMENI" study).

This study aimed to provide real-world safety and effectiveness data of everolimus (EVE) plus exemestane (EXE) in estrogen receptor positive/human epidermal growth factor receptor 2 negative (ER+/HER2-) advanced breast cancer (aBC). This prospective observational study was conducted by 19 hospital-based oncologists in Greece. Eligible patients were treated with EVE+EXE in the first-line setting; EVE was initiated according to the approved label. Overall, 75 eligible patients (mean age: 66.9 years; visceral metastases: 49.3%; bone-only metastases: 37.3%) were included in the effectiveness analyses. Over a median (interquartile range) of 12.1 months (range=4.2-20.5 months) of EVE treatment, the median progression-free survival was 18.0 months and the overall response rate was 22.7%. Among patients that received ≥1 EVE dose (n=80), the incidence of EVE-related adverse events was 72.5% (serious: 55.0%); stomatitis (22.5%), fatigue (22.5%), pneumonitis (18.8%); and cough (18.8%) were the most common. In the routine care in Greece, EVE demonstrates clinical benefit and a predictable safety profile.

Lipid Changes During Endocrine Therapy in Breast Cancer Patients: The Results of a 5-Year Real-World Retrospective Analysis.

BackgroundThe aim of this study was to investigate the status of serum lipids during endocrine therapy.MethodsWe retrospectively analysed lipid profiles during the 5-year treatment of 1487 consecutive postoperative BC patients. Lipid parameters included triglycerides (TG), total cholesterol (TC), low-density lipoprotein (LDL-C) and high-density lipoprotein (HDL-C). Those biomarkers were measured at baseline and 1, 2, 3, 4 and 5 years following the initiation of endocrine therapy.ResultsFor premenopausal BC patients, LDL levels rapidly decreased at 1 year in the tamoxifen (TAM) group compared with baseline levels (p<0.05), and this decline remained for the following 4 years. Additionally, LDL levels were significantly lower in the TAM group than in the nonendocrine group at all assessment time points (p<0.05). Similarly, TC levels also decreased in the TAM group compared with baseline levels at all assessment time points (p<0.05), and compared with the levels in the nonendocrine group, TC levels were also lower for the first 4 years. For postmenopausal BC patients, there was no significant difference in the lipid profiles (TG, TC, LDL and HDL) in the letrozole (LET), anastrozole (ANA) or exemestane (EXE) groups compared with the nonendocrine group. For patients who received TAM, compared with the nonendocrine group, TC levels decreased at 1 year, and LDL levels decreased at 1 and 2 years.ConclusionsTAM may improve LDL and TC levels in premenopausal BC patients. In postmenopausal BC patients, aromatase inhibitors (AIs) may have no adverse effects on lipid profiles, and TAM may have limited beneficial effects on serum lipids.

Real-Life Analysis of Efficacy and Safety of Everolimus Plus Exemestane in Hormone Receptor-Positive, Human Epidermal Growth Factor Receptor-2-Negative Metastatic Breast Cancer Patients: A Turkish Oncology Group (TOG) Study

Purpose This study evaluated the efficacy and safety of everolimus (EVE) plus exemestane (EXE) in hormone-receptor positive (HR+), human epidermal growth factor receptor-2-negative (HER2−) metastatic breast cancer (MBC) patients in real-life settings. Methods Overall, 204 HR+, HER2− MBC patients treated with EVE + EXE after progressing following prior endocrine treatment were included. Overall survival (OS) and progression-free survival (PFS) and safety data were analyzed. Results The objective response rate, median PFS, and median OS were 33.4%, 8.9 months, and 23.4 months, respectively. Multivariate analysis revealed that negative progesterone receptor status was a significant determinant of poor treatment response (p = 0.035) and PFS (p = 0.024). The presence of bone-only metastasis was associated with better treatment response (p = 0.002), PFS (p < 0.001), and OS (p = 0.001). Conclusion We confirmed the favorable efficacy and safety profile of EVE + EXE for HR+, HER − MBC patients.

Characterization of Cytosolic Glutathione S-Transferases Involved in the Metabolism of the Aromatase Inhibitor, Exemestane.

Exemestane (EXE) is a hormonal therapy used to treat estrogen receptor-positive breast cancer by inhibiting the final step of estrogen biosynthesis catalyzed by the enzyme aromatase. Cysteine conjugates of EXE and its active metabolite 17β-dihydro-EXE (DHE) are the major metabolites found in both the urine and plasma of patients taking EXE. The initial step in cysteine conjugate formation is glutathione conjugation catalyzed by the glutathione S-transferase (GST) family of enzymes. The goal of the present study was to identify cytosolic hepatic GSTs active in the GST-mediated metabolism of EXE and 17β-DHE. Twelve recombinant cytosolic hepatic GSTs were screened for their activity against EXE and 17β-DHE, and glutathionylated EXE and 17β-DHE conjugates were detected by ultra-performance liquid chromatography tandem mass spectrometry. GST α (GSTA) isoform 1, GST μ (GSTM) isoform 3 and isoform 1 were active against EXE, whereas only GSTA1 exhibited activity against 17β-DHE. GSTM1 exhibited the highest affinity against EXE with a Michaelis-Menten constant (KM) value that was 3.8- and 7.1-fold lower than that observed for GSTA1 and GSTM3, respectively. Of the three GSTs, GSTM3 exhibited the highest intrinsic clearance against EXE (intrinsic clearance = 0.14 nl·min-1·mg-1). The KM values observed for human liver cytosol against EXE (46 μM) and 17β-DHE (77 μM) were similar to those observed for recombinant GSTA1 (53 and 30 μM, respectively). Western blot analysis revealed that GSTA1 and GSTM1 composed 4.3% and 0.57%, respectively, of total protein in human liver cytosol; GSTM3 was not detected. These data suggest that GSTA1 is the major hepatic cytosolic enzyme involved in the clearance of EXE and its major active metabolite, 17β-DHE. SIGNIFICANCE STATEMENT: Most previous studies related to the metabolism of the aromatase inhibitor exemestane (EXE) have focused mainly on phase I metabolic pathways and the glucuronidation phase II metabolic pathway. However, recent studies have indicated that glutathionylation is the major metabolic pathway for EXE. The present study is the first to characterize hepatic glutathione S-transferase (GST) activity against EXE and 17β-dihydro-EXE and to identify GST α 1 and GST μ 1 as the major cytosolic GSTs involved in the hepatic metabolism of EXE.

238P BOLERO-5: A phase II study of everolimus and exemestane combination in Chinese post-menopausal women with ER+/HER2- advanced breast cancer

The results of the global BOLERO-2 trial established the efficacy and safety of combination everolimus (EVE, an mTOR inhibitor) and exemestane (EXE) in the treatment of ER+, HER2-, locally advanced, recurrent, or metastatic breast cancer (ABC). BOLERO-5 investigated this combination in Chinese post-menopausal women with ER+, HER2- ABC, refractory to letrozole or anastrozole (NCT03312738).

Exemestane encapsulated polymer-lipid hybrid nanoparticles for improved efficacy against breast cancer: optimization, in vitro characterization and cell culture studies

Polymer-lipid hybrid nanoparticles (PLHNPs) are novel nanoplatforms for the effective delivery of a lipophilic drug in the management of a variety of solid tumors. The present work was designed to develop exemestane (EXE) encapsulated D-alpha-tocopheryl polyethylene glycol succinate (TPGS) based PLHNPs (EXE-TPGS-PLHNPs) for controlled delivery of EXE for breast cancer management. EXE-TPGS-PLHNPs were formulated by single-step nano-precipitation technique and statistically optimized by a 33 Box–Behnken design using Design expert® software. The polycaprolactone (PCL; X 1), phospholipon 90 G (PL-90G; X 2), and surfactant (X 3) were selected as independent factors while particles size (PS; Y 1), polydispersity index (PDI; Y 2), and %entrapment efficiency (%EE; Y 3) were chosen as dependent factors. The average PS, PDI, and %EE of the optimized EXE-TPGS-PLHNPs was observed to be 136.37 ± 3.27 nm, 0.110 ± 0.013, and 88.56 ± 2.15% respectively. The physical state of entrapped EXE was further validated by Fourier-transform infrared spectroscopy, differential scanning calorimetry, and powder x-ray diffraction that revealed complete encapsulation of EXE in the hybrid matrix of PLHNPs with no sign of significant interaction between drug and excipients. In vitro release study in simulated gastrointestinal fluids revealed initial fast release for 2 h after that controlled release profile up to 24 h of study. Moreover, optimized EXE-TPGS-PLHNPs exhibited excellent stability in gastrointestinal fluids as well as colloidal stability in different storage concentrations. Furthermore, EXE-TPGS-PLHNPs exhibited distinctively higher cellular uptake and time and dose-dependent cytotoxicity against MCF-7 breast tumor cells compared to EXE-PLHNPs without TPGS and free EXE. The obtained results suggested that EXE-TPGS-PLHNPs can be a promising platform for the controlled delivery of EXE for the effective treatment of breast cancer.

Alpelisib in combination with everolimus ± exemestane in solid tumours: Phase Ib randomised, open-label, multicentre study

Background and purposeCombined mTORC1 inhibition with everolimus (EVE) and phosphatidylinositol 3-kinase catalytic subunit p110α blockade with alpelisib (ALP) has demonstrated synergistic efficacy in preclinical models and supports testing the combination of ALP and EVE in the clinical setting. The primary objective was to determine the maximum tolerated dose (MTD)/recommended dose for expansion (RDE) of ALP in combination with EVE and in combination with EVE and exemestane (EXE) and subsequently assess safety, preliminary efficacy and effect of ALP on the pharmacokinetics of EVE and determine the magnitude of the drug-drug interaction. Patients and methodsDose escalation phases were conducted in patients with advanced solid tumours and in postmenopausal women with hormone receptor–positive (HR+), human epidermal growth factor receptor 2–negative (HER2–) advanced breast cancer (ABC). The dose expansion phase was conducted in patients with pancreatic neuroendocrine tumour and renal cell carcinoma (RCC) (both mechanistic target of rapamycin inhibitor [mTORi]–naive), in patients with mTORi-pretreated solid tumours and in postmenopausal women with HR+, HER2– ABC. ResultsDuring the doublet escalation phase, dose-limiting toxicities (DLTs) were reported in 5 of 10 (50%) patients: one patient had grade (Gr) 2 hyperglycemia and one patient had Gr 3 diarrhoea in the 300 mg dose group, one patient had Gr 2 hyperglycemia and one patient had Gr 4 hypocalcaemia in the 250 mg dose group, and one patient in the 200 mg dose group had Gr 3 diarrhoea and Gr 3 stomatitis. The combination of ALP 250 mg + EVE 2.5 mg was declared as the MTD/RDE in subjects with advanced solid tumours. In the triplet escalation phase, one patient who received ALP 200 mg + EVE 2.5 mg + EXE 25 mg had a DLT of Gr 3 acute kidney injury. This dose combination was declared as the MTD and RDE in subjects with advanced HR-positive HER2-negative BC. The common adverse events (≥30% patients), occurring across all phases, were hyperglycaemia, stomatitis, diarrhoea, nausea, asthenia, decreased appetite and fatigue. The sixteen-week progression-free survival rate was 52.4% (90% confidence interval [CI]: 32.8, 71.4) in the RCC cohort, 35.3% (90% CI: 16.6, 58.0) in the prior pNET cohort and 30.0% (90% CI: 8.7, 60.7) in the prior mTORi cohort. The pharmacokinetics of 2.5 mg of EVE was largely unchanged in the presence of ALP, independent of the dose (250 mg or 300 mg). There were no clinically relevant drug-drug interactions observed between ALP and EVE. ConclusionThe overall safety profile of ALP with EVE and EXE is manageable and reversible; no unexpected safety signals were noted compared with the individual safety profiles. Pharmacokinetics of ALP, EVE and EXE was largely unchanged in combination with each other.

A novel electrochemical sensor based on functionalized glassy carbon microparticles@CeO2 core–shell for ultrasensitive detection of breast anticancer drug exemestane in patient plasma and pharmaceutical dosage form

A novel core–shell structure composed of functionalized glassy carbon microspheres (f-GC) as core and CeO2 nanoparticles as shell was successfully synthesized by using hydrothermal process (H). The morphology and composition of the as-prepared f-GC@CeO2-H core–shell microspheres were characterized using XRD, SEM, TEM, EDX and mapping analysis. Electrochemical investigations revealed that f-GC@CeO2-H modified carbon rod electrode (CRE) possessed intriguing properties towards electrosensing breast anticancer exemestane (EXE) due to the synergistic interactions between f-GC core and CeO2 nanoparticles shell. The newly sensor f-GC@CeO2-H/CRE exhibited a high electrocatalytic activity towards electro-reduction of EXE and under the optimal conditions, the linear range of EXE was 0.05 µM to 10.9 µM with a low limit of detection of 18 nM. Furthermore, electrosensing of the steroidal aromatase inhibitor EXE in the presence of the non-steroidal aromatase inhibitor letrozole (LTZ) was achieved without anti-interference ability. The developed sensor shows admirable sensitivity in the detection of the two aromatase inhibitors simultaneously in biologically relevant samples. Finally, the proposed sensor was very effective for EXE determination from commercial tablets, human fluids and clinical patient blood.

Safety and efficacy of everolimus (EVE) plus exemestane (EXE) in postmenopausal women with locally advanced or metastatic breast cancer: final results from EVEREXES.

This study was conducted to collect clinical safety, tolerability, and efficacy data with the use of everolimus (EVE) combined with exemestane (EXE) in patients with advanced breast cancer (ABC). The EVEREXES trial initiated in 2012, provided early access to the first dual blockade treatment with EVE + EXE in patients with HR+, HER2 - ABC in Asia and other emerging growth countries. Postmenopausal women with HR+, HER2 - ABC who had documented recurrence or progression, following a nonsteroidal aromatase inhibitor therapy, were treated with EVE (10mg/day) + EXE (25mg/day) orally. A total of 235 patients received ≥ 1 dose of study medication. At the end of the study, all patients ceased the treatment. Disease progression (66.0%) was the primary reason of discontinuation. The most common AEs (≥ 20%) were stomatitis, decreased appetite, hyperglycemia, rash, aspartate aminotransferase increased, anemia, alanine aminotransferase increased, cough, and fatigue. No new safety concerns were identified in the current study. Median progression-free survival (PFS) in the Asian subset was similar to that of the overall population (9.3months in both groups). Confirmed overall response rate (ORR) was achieved for 19.6% of the patients. Efficacy of EVE + EXE across subgroups (prior CT, line of treatment, and presence of visceral metastases) was maintained. The safety and efficacy results from EVEREXES trial are consistent to data previously reported in BOLERO-2. These results support that EVE + EXE could be a viable treatment option for the postmenopausal women with HR+, HER2 - ABC in Asian region.

Thermoresponsive liquid crystalline formulation of Exemestane: Design and structural characterization

Exemestane (EXE), a drug used for the treatment of breast cancer, has limited aqueous solubility of 0.08 mg/mL and log P∼ 4.22. The only available marketed formulation in form of tablets possess limitations of poor oral absorption (∼ 42 %), low solubility, extensive hepatic metabolism and numerous adverse effects due to its peripheral absorption. In order to address these issues, an alternative route of topical application is attempted through a lamellar liquid crystal based formulation. Pluronic® was used as stabilizer due to its higher surface activity and gelling properties. The solubility enhancement of EXE was achieved using liquid crystal formulation. We have investigated the effect of concentration of oil, Smix (surfactant – cosurfactant mixture) and EXE on lattice parameter, rheology and drug release for various combinations of the formulation. The small angle x-ray scattering (SAXS) measurement demonstrated an evidence of a lamellar structure with lattice parameter ∼15 nm, which increases with corresponding increase in oil and EXE due to increase in hydrophobic interactions leading to an expansion of lamella. The inter lamellar distance decreases at higher surfactant concentration, due to the distribution of the same amount of oil and drug within larger concentration of surfactant molecules. The rheology measurement exhibited gel like properties at low shear rate indicating soft gel formation, which converts to Newtonian type flowing liquid at higher shear rate. At constant Smix with increasing oil content, the viscosity decreases, which is attributed to the dilution of the lamellar structures with oil. The temperature sweep rheology reveals a change in the viscosity near physiological temperature, which may be attributed to the structural transition of lamellae. The formulation remains gel like at room temperature, which aids in proper application to skin and converts it to free flowing liquid above 37 °C. The invitro drug release of optimized formulation for 24 h was ∼ 38 % at 37 °C, which increased to 50 % at 42 °C. Accordingly, this formulation containing thermoresponsive lamellar liquid crystal gels of EXE represents a viable option for hyperthermia induced enhanced drug release. The characteristic and advantageous features offered by this formulation includes improved bioavailability of EXE due to enhanced solubility, permeability and absorption.

Abstract OT-28-05: Solti-1718 NEREA trial: Neratinib in hormone receptor (HR)-positive/HER2-negative HER2-Enriched (HER2-E) advanced breast cancer (BC)

Abstract Background: HR+/HER2-negative BC represent ∼70% of all newly diagnosed breast tumors. BC is a clinically and biologically heterogenous disease where intrinsic subtypes play a role(1-3). Non-luminal subtypes within HR+/HER2-negative disease do not benefit at the same extent from standard of care treatments as the luminal subtypes(1). Thus, other strategies are needed. HER2-E subtype represents approximately 6.6-11.0% of HR+/HER2-negative tumors and is enriched in twice as many cases in metastatic tumors. According to EGF30008 trial, HER2-E advance BC patients despite presenting poor outcomes across treatments, showed more benefit from anti-HER2 therapy. SOLTI-1718 NEREA aims to evaluate whether EGFR/ERBB2 axis inhibition by neratinib improves efficacy in terms of progression-free survival (PFS) in patients with advanced HR+/HER2-negative disease resistant to an endocrine treatment (ET). Methods: SOLTI-1718 NEREA is an open-label, single arm, multicenter and multinational phase II clinical trial following a Simon’s 2-stage design with one interim and one final efficacy analysis. Locally advanced or metastatic HER2-E, HR+/HER2-negative BC patients who had recurrence or progression while receiving previous ET will be included. Treatment schedule will consist on neratinib 240 mg daily in combination with ET, with either exemestane, fulvestrant or tamoxifen. All patients will take prophylactic loperamide with an established dosing scheme during the first cycle and on demand in subsequent cycles. Tumor assessments will be performed at baseline and every 8 weeks during the first year, and every 12 weeks thereafter. Interim analysis will be performed after 33 patients are evaluable. If 15 to 27 patients achieved a PFS at 6 months (PFS6), the trial will continue to second stage, otherwise it will be stopped for futility (&amp;lt;15) or efficacy (≥28). A total of 56 evaluable patients will be included in stage I and II. The primary objective is to assess the efficacy of neratinib in combination with ET in HER2-E, HR+/HER2-negative patients in terms of PFS6 by local assessment by the investigator using RECIST v.1.1. Secondary endpoints include clinical benefit rate at 6 months, overall response rate, duration of response, time to response and incidence, duration and severity of adverse events. The Spanish national competent authority approved the study on April 8th 2020. The study will enroll patients in 15 sites in Spain and 3 sites in Portugal. Recruitment will start on July 2020. We thank PUMA BIOTECHNOLOGY, INC for their provision of Neratinib and financial contribution to the study.

Secondary endpoints analysis in patients with estrogen receptor-positive metastatic breast cancer treated with everolimus and exemestane enrolled in Oral Care-BC

BackgroundThe Oral Care BC-trial reported that professional oral care (POC) reduces the incidence and severity of oral mucositis in patients receiving everolimus (EVE) and exemestane (EXE). However, the effect of POC on clinical response among patients receiving EVE and EXE was not established. We compared outcomes for estrogen receptor-positive metastatic breast cancer patients who received POC to those who had not, and evaluated clinical prognostic factors. All patients simultaneously received EVE and EXE.MethodsBetween May 2015 and Dec 2017, 174 eligible patients were enrolled in the Oral Care-BC trial. The primary endpoint was the comparative incidence of grade 1 or worse oral mucositis, as evaluated for both the groups over 8 weeks by an oncologist. The secondary endpoints were progression-free survival (PFS) and overall survival (OS). Data were collected after a follow-up period of 13.9 months.ResultsThere were no significant differences in PFS between the POC and Control Groups (P = 0.801). A BMI < 25 mg/m2 and non-visceral metastasis were associated with longer PFS (P = 0.018 and P = 0.003, respectively) and the use of bone modifying agents (BMA) was associated with shorter PFS (P = 0.028). The PFS and OS between the POC and control groups were not significantly different in the Oral-Care BC trial.ConclusionsPOC did not influence the prognosis of estrogen receptor-positive metastatic breast cancer patients. Patients with non-visceral metastasis, a BMI < 25 mg/m2, and who did not receive BMA while receiving EVE and EXE may have better prognoses.Trial registrationThe study protocol was registered online at the University Hospital Medical Information Network (UMIN), Japan (protocol ID 000016109), on January 5, 2015 and at ClinicalTrials.gov (NCT02376985).

Everolimus Plus Exemestane Treatment in Patients with Metastatic Hormone Receptor-Positive Breast Cancer Previously Treated with CDK4/6 Inhibitor Therapy.

The combination of everolimus (EVE) and exemestane (EXE) is approved for the treatment of patients with metastatic hormone receptor-positive breast cancer (mHRBC) who progress on nonsteroidal aromatase inhibitor (NSAI) therapy. However, none of the patients enrolled in the trial that led to this approval (BOLERO-2) had previously received CDK4/6 inhibitors (CDK4/6is), which have since become a frontline standard of care for mHRBC. As such, the clinical benefit of EVE plus EXE in patients who have previously received CDK4/6is remains unknown. Adult patients with mHRBC at our institution who progressed on an NSAI plus CDK4/6i or NSAI therapy alone and were treated with at least one cycle of EVE plus EXE between 2012 and 2018 were analyzed. Collected data included patient demographics, treatment history, adverse events, and clinical outcomes. Primary objectives were to compare progression-free survival (PFS) and overall survival (OS) between patients who received prior NSAI plus CDK4/6i therapy versus an NSAI alone. Among 43 patients, 17 had prior CDK4/6i exposure. With the exception of de novo metastatic disease, patient and disease characteristics were comparable across treatment cohorts. There was no significant difference in PFS (median, 3.6 vs. 4.2 months) or OS (median, 15.6 vs. 11.3 months) between patients who had received prior CDK4/6is and those who had not, respectively. Prior exposure to CDK4/6i therapy did not impact survival outcomes for patients with mHRBC taking EVE plus EXE. However, there was a trend toward improved OS in the CDK4/6i cohort that should be evaluated in larger cohorts. The use of CDK4/6 inhibitors in combination with a nonsteroidal aromatase inhibitor has become a standard frontline therapy in metastatic hormone receptor-positive breast cancer. An approved subsequent line of therapy is everolimus plus exemestane; however, the original data supporting this therapy predated approval of CDK4/6 inhibitors. As such, the clinical benefit of everolimus and exemestane in patients previously treated with a CDK4/6 inhibitor was unknown. This retrospective cohort study offers real-world data demonstrating prior CDK4/6 inhibitor exposure does not impact survival outcomes for everolimus plus exemestane.

Serum biomarkers of inflammation (ferritin, IL-8, TNFR1) and outcomes in BOLERO-2, a phase III trial of HR+/HER2- metastatic breast cancer treated with everolimus (mTOR inhibitor).

1067 Background: Everolimus (EVE) plus exemestane (EXE) doubled PFS while maintaining quality of life versus EXE alone in postmenopausal hormone receptor-positive (HR+), HER2-negative metastatic breast cancer (MBC) (BOLERO-2 phase 3; NCT00863655). Here we investigated several serum biomarkers of inflammation: ferritin, interleukin-8 (IL-8), and tumor necrosis factor receptor 1 (TNFR1). Both higher IL-8 (ASCO 2018, #3025) and TNF (Nature 569:428-32, 2019) have been reported to be associated with worsened outcome to immune checkpoint inhibitors (ICI), and IL-8- and TNF-targeted therapies combined with ICIs are in phase I trials. We evaluated the prognostic/predictive ability of serum ferritin, IL-8, and TNFR1 to everolimus in BOLERO-2. Methods: Serum biomarkers were determined on pretreatment serum samples using the ELLA immunoassay platform (ProteinSimple, San Jose, CA). Cox-proportional hazards model was used to assess the efficacy of EVE, and the prognostic and predictive effect on PFS and OS. Results: Pretreatment serum biomarker levels were determined in 510 patients (70 %) of 725 BOLERO-2 patients randomized 2:1 to EVE+EXE or EXE). Serum levels (25%, 50%, 75%) were: ferritin (68.9, 125.5, 253.1 ng/ml); IL-8 (14.5, 19.4, 27.7 pg/ml); and TNFR1 (1205, 1470, 1868 pg/ml). Ferritin correlated significantly with TNFR1 (r=0.45, p&lt;0.0001), while IL-8 correlated weakly with TNFR1 (r=0.10, p=0.023). Higher levels of all 3 biomarkers were prognostic for significantly shorter PFS and OS (table). But no biomarkers were predictive: everolimus was efficacious regardless of the 3 biomarker levels (p&gt;0.05). Conclusions: High levels of serum ferritin, IL-8, and TNFR1 were significantly associated with shorter PFS and OS in HR+/HER2- MBC patients. Everolimus had superior outcomes compared to placebo, regardless of serum biomarker level. These 3 significant prognostic biomarkers are all associated with increased inflammatory processes through different pathways. Anti-inflammatory therapy targeted against these biomarkers should be evaluated based on serum level as potential combination therapy with everolimus or CDK 4/6 inhibitors in HR+ MBC. [Table: see text]

Structural Recognition and Binding Pattern Analysis of Human Topoisomerase II Alpha with Steroidal Drugs: In Silico Study to Switchover the Cancer Treatment.

Background and objective:Topoisomerase TOP-IIA (TTOP-IIA) is widely used as a significant target for cancer therapeutics because of its involvement in cell proliferation. Steroidal drugs have been suggested for breast cancer treatment as aromatase enzymes inhibitors . TTOP-IIA inhibitors can be used as a target for the development of new cancer therapeutics. Materials and Methods:In this study, we conducted a docking study on steroidal drugs Anastrozole (ANA), Letrozole (LET), and exemestane (EXE) with TTOP-IIA to explore the therapeutic area of these drugs.Results:The binding interaction of EXE drug had significant docking interaction which is followed by ANA and LET. Thus, all these drugs could be used to inhibit the TTOP-IIA mediated cell proliferation and could be a hope to treat the other types of cancers. Among all three tested steroidal drugs, EXE showed binding energy -7.05 kcal/mol, hydrogen bond length1.78289 Å and amino acid involved in an interaction was A: LYS723:HZ3 -: UNK1:O6. Conclusion:The obtained data showed the most significant binding interaction analyzed with the tested enzyme. Thus, in vitro laboratory experimentation and in vivo research are necessary to put forward therapeutic repositioning of these drugs to establish them as a broad spectrum potential anticancer drugs.

Cytosolic glutathione‐S‐transferase A1 (GSTA1) plays a primary role in the metabolic clearance of the aromatase inhibitor, Exemestane

Exemestane (EXE) is used to treat estrogen receptor positive (ER+) breast cancer in postmenopausal women by inhibiting the enzyme aromatase in the final step of estrogen biosynthesis. Variability exists in both overall patient response and adverse events, which may be attributed to inter‐individual variation in EXE metabolism. EXE is metabolized primarily to the active metabolite, 17β‐dihydro‐EXE (17β‐DHE), and preliminary studies have demonstrated that cysteine conjugates of EXE and 17β‐DHE comprise 77% of total EXE metabolites in the urine of patients. Cysteine conjugation is a multi‐step process, the first of which is glutathione (GSH) conjugation, catalyzed by the glutathione‐S‐transferase (GST) family of the enzymes. The goal of the present study was to identify the hepatic GSTs active in the metabolism of EXE and 17β‐DHE. In a screening of the Human Protein Atlas, 12 cytosolic GSTs were found to be hepatically expressed and were initially screened by incubating 0.5 μg of pure recombinant GST enzyme with EXE or 17β‐DHE (125 μM) and reduced glutathione (GSH). The resulting GS‐conjugates of EXE and 17β‐DHE were detected and quantified using UPLC‐MS/MS. Results from the conjugation assays indicated that the cytosolic enzyme GSTA1 is highly active against both EXE and 17β‐DHE, while GSTM3 and GSTM1 are only moderately active against EXE. No other recombinant cytosolic GST enzymes tested (GSTA2, GSTA4, GSTK1, GSTM2, GSTM4, GSTO1, GSTP1, GSTZ1 and GSTT1) exhibited activity against either EXE or 17β‐DHE. KM values for human liver cytosol (HLC) and purified recombinant GSTA1 were similar for both EXE (45 μM vs. 77 μM, respectively) and 17β‐DHE (54 μM and 30 μM, respectively) as substrate, suggesting that GSTA1 may be the main driver for EXE and 17β‐DHE glutathione conjugation in human liver cytosol. Using EXE as a substrate, Vmax value for GSTA1 was &gt;7‐fold higher than that observed for GSTM3 (9.8 nmol/min/mg vs. 1.3 nmol/min/mg, respectively). The EXE intrinsic clearance (ClINT) for GSTA1 (130 nl/min/mg) was &gt;10‐fold higher than that observed for GSTM3 (11 nl/min/mg). These data suggest that GSTA1 may be an important component in the metabolic pathway contributing to the elimination of EXE in breast cancer patients.Support or Funding InformationThis work is supported by grants from NIH, National Cancer Institute (grant R01‐CA164366; to P. Lazarus) and the Health Sciences and Services Authority of Spokane, Washington (grant WSU002292 to College of Pharmacy and Pharmaceutical Sciences, Washington State University)

Abstract OT1-04-03: Alternative dosing of exemestane before surgery in postmenopausal patients with stage 0-II estrogen receptor positive breast cancer: Design and methodology

Abstract Background: The aromatase inhibitor exemestane (EXE) has shown to lower cancer incidence in high-risk postmenopausal women. However, undesirable symptoms and side effects (i.e., bone density loss, musculoskeletal ache, climacteric syndrome) may compromise patient motivation and adherence to a long-term preventive treatment. A less frequent drug schedule, compared to the standard regimen, may be more acceptable to healthy at-risk women. We hypothesized that comparison of two alternative less frequent dose regimens with the standard daily dose regimen will show that it is possible to decrease undesirable symptoms of EXE while still effectively reducing serum estradiol. Trial Design: We are conducting a multi-center, pre-surgical, double-blind, non-inferiority phase IIb study in which 180 postmenopausal women will be randomized to receive either EXE 25 mg/day or 25 mg/three times a week or 25 mg/week for 4 to 6 weeks prior to surgery. Surgery will occur on day 29, 36 or 43 after treatment initiation. Eligible subjects are postmenopausal women with histologically-confirmed ER-positive (ER &amp;gt;10%) primary breast cancer candidates for surgery. Participants with T0-2, N0-1, Mx or with larger tumors who refuse neo-adjuvant therapy before surgery are eligible. Subjects are stratified according to participating site and body mass index (&amp;lt;25 kg/m2 versus &amp;gt;25 kg/m2). The primary objective is to assess if the reduction in estradiol with EXE 25 mg/three times a week and EXE 25 mg/week is comparable with the standard dose of 25 mg/day of EXE. Methods: Blood will be collected at baseline and at the end of treatment. Tissue samples will be collected from the diagnostic biopsy and at the time of surgery. The primary endpoint is the percentage change of serum estradiol concentration between baseline and surgery in the three arms in a CLIA certified laboratory. Given the expected reduction of at least 80% change with EXE at 25 mg daily considered as reference group (control arm) against 25 mg/three times a week or 25 mg weekly, for the power calculation we assume a non-inferiority difference of 6% in percentage changes of circulating estradiol after treatment from baseline, using a one-sided, two-sample t-test. Secondary outcome measures are the incidence of toxicity and menopausal symptoms according to the CTCAE (v4) and by the self-administered MENQoL; the effect of the three regimens on sex hormones (estrone, estrone sulphate, SHBG, testosterone, DHEAS and FSH) and the effect on circulating estradiol levels using an ultrasensitive method given that the serum levels in postmenopausal women under EXE may be very low. Drug and metabolites levels will be measured in blood, cancer tissue and non-cancer tissue. Evaluation of serum insulin, glucose (homeostatic model assessment index), and lipid profile (total cholesterol, high-density lipoprotein cholesterol and triglycerides), leptin and adiponectin will be performed before and after treatment. Additionally, we will measure breast estradiol concentration in cancer and non-cancer tissue and compare changes in ER, PgR, and proliferation in cancer and non-cancer tissue samples obtained at time of biopsy and definitive surgery. Finally, we will also analyze the role of the polymorphic UGT2B17 gene (involved in EXE and 17-dihydroexemestane metabolism) as well as tissue proteomics. Preliminary results: Enrollment started in February 2017 and as of July 3, 2019, a total of 170/180 participants have been randomized (94% of the expected sample size). Preliminary data will be presented at the conference. IND Sponsor: NCI/DCP NCI contract: HHSN26120120034I Citation Format: Aliana Guerrieri-Gonzaga, Parjhitham Thomas, Andrea DeCensi, Katherine D Crew, Nagi Kumar, Sara Gandini, Lana Vornik, Brandy Heckman-Stoddard, Eva Szabo, Eileen Dimond, Jack Lee, Diane Liu, Matteo Lazzeroni, Sara Cagnacci, Davide Serrano, Mauro D'Amico, Flavio Guasone, Tania Buttiron Webber, Powel Brown, Bernardo Bonanni. Alternative dosing of exemestane before surgery in postmenopausal patients with stage 0-II estrogen receptor positive breast cancer: Design and methodology [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr OT1-04-03.

Abstract P5-11-04: A phase I/IIb study of palbociclib (PALBO) plus everolimus (EVE) and exemestane (EXE) in hormone-receptor positive (HR+)/HER2- metastatic breast cancer (MBC) after progression on a CDK4/6 inhibitor (CDK4/6i): Results of the phase II study

Abstract Background: For patients (pts) with HR+ /HER2- MBC, the optimal regimen following disease progression on the combination of a CDK4/6i plus endocrine therapy (ET) is unknown, and there is a need to evaluate whether continued CDK 4/6 blockade is beneficial in subsequent lines of therapy. Methods: We developed an investigator initiated Phase I/II, open-label trial (NCT02871791) of triplet therapy: palbociclib (PALBO; CDK4/6i) + everolimus (EVE; mTOR inhibitor) + exemestane (EXE; ET) in men or postmenopausal women with measurable HR+ /HER2− MBC who had progressed on prior CDK4/6i and a non-steroidal aromatase inhibitor (NSAI). Pts may have received any number of prior lines of ET, and 0-1 prior line of chemotherapy. Exclusion criteria included prior use of mTORi or EXE. The primary objective was to estimate efficacy of the combination, defined as the clinical benefit rate (CR+PR+SD&amp;gt;6mo). With a one-sided alpha of 0.1, the study had 90% power to detect an improvement in CBR from 40% to 65%. The phase I determined RP2D to be PALBO 100 mg/day (21 of 28 days) + EVE 5mg/day + EXE 25mg/day (previously presented). For pts who entered into the phase IIa part of the study, a research biopsy at baseline and serial research blood collection for circulating tumor DNA (ctDNA) analysis were mandatory. The tumor tissue underwent whole exome sequencing and RNA sequencing and the ctDNA underwent whole exome sequencing. Here we present the first results of the phase 2 study of this triplet regimen. Results: As of June 29, 2019, after a median follow up of 3.8 (2.8-6.2) months, 32 patients were evaluable in the phase II portion of the study. The triplet combination was associated with a clinical benefit rate of 12.5% (n=4), which did not meet the predefined primary endpoint threshold (65%). There were no objective responses achieved. The median PFS was 3.8 (95%CI: 2.0-8.4) months and the 1-year PFS was 16.1% (95%CI: 3.1%-38.0%). The most common AEs were mucositis (all grades, 87.5%; grade 3/4, 15.6%), neutropenia (all grades 84.4%; grade 3/4, 71.9%), and fatigue (all grades 53.1%; grade 3/4, 0%). Data regarding genomic alterations and its association with outcomes will be presented. Conclusions: Among patients with metastatic HR+/HER2- MBC who had previous progression on a NSAI and a CDK 4/6i, there did not appear to be benefit from the addition of PALBO to EXE and EVE, but there were added toxicities. These findings suggest further evaluation of this triplet combination in patients with CDK 4/6i resistance is not warranted. Genomic data from baseline biopsies and circulating tumor DNA will be presented and may help us to explain why patients included in this study were intrinsically resistant to the triplet. Citation Format: Romualdo Barroso-Sousa, Tianyu Li, Lorenzo Trippa, Rebecca Rees, Chelsea Andrews, Arlindo R Ferreira, Karla Helvie, Ann H Partridge, Beth Overmoyer, Eric P Winer, Nikhil Wagle, Sara M Tolaney. A phase I/IIb study of palbociclib (PALBO) plus everolimus (EVE) and exemestane (EXE) in hormone-receptor positive (HR+)/HER2- metastatic breast cancer (MBC) after progression on a CDK4/6 inhibitor (CDK4/6i): Results of the phase II study [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P5-11-04.