scholarly journals Aromatase inhibitors in breast cancer.

2004 ◽  
Vol 11 (2) ◽  
pp. 179-189 ◽  
Author(s):  
P E L√∏nning

The development of aromatase inhibitors for breast cancer therapy is a result of successful translational research exploring the biochemical effects of different compounds in vivo. Studies assessing plasma oestrogen levels as well as in vivo aromatase inhibition have revealed a consistent difference with respect to biochemical efficacy between the third generation compounds (anastrozole, letrozole and exemestane) and the previous, first and second generation drugs, corresponding to the improved clinical effects of these compounds as outlined in large phase III studies. Thus, endocrine evaluation has been found to be a valid surrogate parameter for clinical efficacy. Moreover, the results from these studies have added important biological information to our understanding of endocrine regulation of breast cancer. Based on the clinical results so far, aromatase inhibitors are believed to play a key role in future adjuvant therapy of postmenopausal breast cancer patients and potentially also for breast cancer prevention. Interesting findings such as the lack of cross-resistance between steroidal and non-steroidal compounds should be further explored, as this may add additional information to our understanding of breast cancer biology.

1994 ◽  
Vol 12 (11) ◽  
pp. 2460-2470 ◽  
Author(s):  
P E Goss ◽  
K M Gwyn

PURPOSE AND DESIGN: One way to deprive hormone-dependent breast cancer of estrogen is to prevent its synthesis. This is achievable by inhibiting the aromatase cytochrome P-450 (P-450arom) enzyme complex responsible for the ultimate step in estrogen production. A new generation of specific and selective aromatase inhibitors is currently under investigation. The purpose of this review is to outline the preclinical test systems for screening these inhibitors, to summarize the preclinical and clinical data published to date, and to discuss the future application of these inhibitors in the management of breast cancer. RESULTS AND CONCLUSION: Disadvantages to the use of earlier inhibitors are described. In vitro and in vivo experiments that reflect the potency and selectivity of new inhibitors are highlighted. From preliminary clinical trials, these inhibitors appear to have excellent pharmacokinetic profiles and produce few side effects when administered orally. Activity against postmenopausal metastatic breast cancer has been demonstrated for the agents reviewed. They are all now in phase III testing to determine their relative efficacy in this setting. Their application in combination with both hormone therapy and chemotherapy, in premenopausal metastatic disease, and in the adjuvant setting in both premenopausal and postmenopausal women remains to be defined.


2005 ◽  
Vol 11 (3) ◽  
pp. 96-102 ◽  
Author(s):  
Simon Chowdhury ◽  
Paul A Ellis

The aromatase enzyme catalyses the last step in estrogen biosynthesis. There are two classes of third-generation aromatase inhibitors: irreversible steroidal inhibitors (e.g. exemestane) and reversible non-steroidal inhibitors (e.g. anastrozole, letrozole). All three agents have been found to be equivalent or superior to megestrol acetate as second-line therapy for metastatic breast cancer. In the first-line setting, large phase III trials have shown that all three are equivalent or superior to tamoxifen in women with metastatic disease. Several large trials with varying study designs have been launched to analyse their role in the adjuvant setting. The four that have reported found longer average disease-free survival for women who received an aromatase inhibitor than for those who did not. In addition, one trial, MA.17, has shown a survival advantage associated with the use of an aromatase inhibitor in node-positive patients. Guidelines produced by the American Society of Clinical Oncology suggest that adjuvant therapy for postmenopausal women with hormone-receptor-positive breast cancer should include an aromatase inhibitor. However, the long-term consequences of estrogen deprivation in postmenopausal women remain uncertain, particularly with regard to bone and cardiovascular health. The advantages and disadvantages of different hormonal strategies should therefore be carefully considered in each individual case.


2013 ◽  
Vol 31 (11) ◽  
pp. 1398-1404 ◽  
Author(s):  
Paul E. Goss ◽  
James N. Ingle ◽  
Kathleen I. Pritchard ◽  
Matthew J. Ellis ◽  
George W. Sledge ◽  
...  

Purpose In patients with hormone-dependent postmenopausal breast cancer, standard adjuvant therapy involves 5 years of the nonsteroidal aromatase inhibitors anastrozole and letrozole. The steroidal inhibitor exemestane is partially non–cross-resistant with nonsteroidal aromatase inhibitors and is a mild androgen and could prove superior to anastrozole regarding efficacy and toxicity, specifically with less bone loss. Patients and Methods We designed an open-label, randomized, phase III trial of 5 years of exemestane versus anastrozole with a two-sided test of superiority to detect a 2.4% improvement with exemestane in 5-year event-free survival (EFS). Secondary objectives included assessment of overall survival, distant disease–free survival, incidence of contralateral new primary breast cancer, and safety. Results In the study, 7,576 women (median age, 64.1 years) were enrolled. At median follow-up of 4.1 years, 4-year EFS was 91% for exemestane and 91.2% for anastrozole (stratified hazard ratio, 1.02; 95% CI, 0.87 to 1.18; P = .85). Overall, distant disease–free survival and disease-specific survival were also similar. In all, 31.6% of patients discontinued treatment as a result of adverse effects, concomitant disease, or study refusal. Osteoporosis/osteopenia, hypertriglyceridemia, vaginal bleeding, and hypercholesterolemia were less frequent on exemestane, whereas mild liver function abnormalities and rare episodes of atrial fibrillation were less frequent on anastrozole. Vasomotor and musculoskeletal symptoms were similar between arms. Conclusion This first comparison of steroidal and nonsteroidal classes of aromatase inhibitors showed neither to be superior in terms of breast cancer outcomes as 5-year initial adjuvant therapy for postmenopausal breast cancer by two-way test. Less toxicity on bone is compatible with one hypothesis behind MA.27 but requires confirmation. Exemestane should be considered another option as up-front adjuvant therapy for postmenopausal hormone receptor–positive breast cancer.


Author(s):  
Nazli Bahrami ◽  
Shakila Jabeen ◽  
Andliena Tahiri ◽  
Torill Sauer ◽  
Hilde Presterud Ødegård ◽  
...  

Abstract Purpose The aromatase inactivator exemestane may cause clinical disease stabilization following progression on non-steroidal aromatase inhibitors like letrozole in patients with metastatic breast cancer, indicating that additional therapeutic effects, not necessarily related to estrogen-suppression, may be involved in this well-known “lack of cross-resistance”. Methods Postmenopausal women with ER positive, HER-2 negative, locally advanced breast cancer were enrolled in the NEOLETEXE-trial and randomized to sequential treatment starting with either letrozole (2.5 mg o.d.) or exemestane (25 mg o.d.) followed by the alternative aromatase inhibitor. Serum levels of 54 cytokines, including 12 adipokines were assessed using Luminex xMAP technology (multiple ELISA). Results Serum levels of leptin were significantly decreased during treatment with exemestane (p < 0.001), regardless whether exemestane was given as first or second neoadjuvant therapy. In contrast, letrozole caused a non-significant increase in serum leptin levels in vivo. Conclusions Our findings suggest an additional and direct effect of exemestane on CYP-19 (aromatase) synthesis presumably due to effects on the CYP19 promoter use that is not present during therapy with the non-steroidal aromatase inhibitor letrozole. Our findings provide new insights into the influence of clinically important aromatase inhibitors on cytokine levels in vivo that contribute to the understanding of the clinically observed lack of cross-resistance between non-steroidal and steroidal aromatase inhibitors in breast cancer patients. Trial registration Registered on March 23rd 2015 in the National trial database of Norway (Registration number: REK-SØ-84-2015).


2020 ◽  
Vol 20 (17) ◽  
pp. 1994-2004 ◽  
Author(s):  
Pooja Ratre ◽  
Keerti Mishra ◽  
Amit Dubey ◽  
Amber Vyas ◽  
Akhlesh Jain ◽  
...  

Background: Estrogens are essential for the growth of breast cancer in the case of premenopausal as well as in postmenopausal women. However, most of the breast cancer incidences are reported in postmenopausal women and the concurrent risk surges with an increase in age. Since the enzyme aromatase catalyses essential steps in estrogen biosynthesis, Aromatase Inhibitors (AIs) are effective targeted therapy in patients with Estrogen Receptor positive (ER+) breast cancer. AIs are more effective than Selective Estrogen Receptor Modulators (SERMs) because they block both the genomic and nongenomic activities of ER. Till date, first, second and third-generation AIs have been approved by the FDA. The third-generation AIs, viz. Letrozole, Anastrozole, Exemestane, are currently used in the standard treatment for postmenopausal breast cancer. Methods: Data were collected from Medline, PubMed, Google Scholar, Science Direct through searching of keywords: ‘aromatase’, ‘aromatase inhibitors’, ‘breast cancer’, ‘steroidal aromatase inhibitors’, ‘non-steroidal inhibitors’ and ‘generations of aromatase inhibitors’. Results: In the current scenario of breast cancer chemotherapy, AIs are the most widely used agents which reveal optimum efficacy along with the least side effects. Keeping in view the prominence of AIs in breast cancer therapy, this review covered the detailed description of aromatase including its role in the biosynthesis of estrogen, biochemistry, gene expression, 3D-structure, and information of reported AIs along with their role in breast cancer treatment. Conclusion: AIs are the mainstream solution of the ER+ breast cancer treatment regimen with the continuous improvement of human understanding of the importance of a healthy life of women suffering from breast cancer.


2015 ◽  
Vol 86 (7) ◽  
pp. 906-916 ◽  
Author(s):  
L. Susan Taichman ◽  
Marita R. Inglehart ◽  
William V. Giannobile ◽  
Thomas Braun ◽  
Giselle Kolenic ◽  
...  

2001 ◽  
Vol 19 (3) ◽  
pp. 881-894 ◽  
Author(s):  
Paul E. Goss ◽  
Kathrin Strasser

PURPOSE: The purpose of this article is to provide an overview of the current clinical status and possible future applications of aromatase inhibitors in breast cancer. METHODS: A review of the literature on the third-generation aromatase inhibitors was conducted. Some data that have been presented but not published are included. In addition, the designs of ongoing trials with aromatase inhibitors are outlined and the implications of possible results discussed. RESULTS: All of the third-generation oral aromatase inhibitors—letrozole, anastrozole, and vorozole (nonsteroidal, type II) and exemestane (steroidal, type I)—have now been tested in phase III trials as second-line treatment of postmenopausal hormone-dependent breast cancer. They have shown clear superiority compared with the conventional therapies and are therefore considered established second-line hormonal agents. Currently, they are being tested as first-line therapy in the metastatic, adjuvant, and neoadjuvant settings. Preliminary results suggest that the inhibitors might displace tamoxifen as first-line treatment, but further studies are needed to determine this. CONCLUSION: The role of aromatase inhibitors in premenopausal breast cancer and in combination with chemotherapy and other anticancer treatments are areas of future exploration. The ongoing adjuvant trials will provide important data on the long-term safety of aromatase inhibitors, which will help to determine their suitability for use as chemopreventives in healthy women at risk of developing breast cancer.


2019 ◽  
Vol 9 (1) ◽  
pp. 11
Author(s):  
Reham M. Faheim ◽  
Eman A. El-Shaarawy ◽  
Dina A. Salem ◽  
Rehab G. Shaaban

Background: Aromatase inhibitors (AIs) represent an effective endocrine treatment for hormone receptor-positive postmenopausal breast cancer patients with early stage or metastatic disease.Objective: Assessment of Cardiotoxicity in Hormone positive Postmenopausal Breast Cancer Patients receiving AIs (upfront orswitch therapy).Methods: This cross sectional study included 123 postmenopausal breast cancer patients presented to the Clinical Oncology Department, Ain Shams University (Cairo, Egypt) in the interval from August 2016 to June 2017 with hormone receptor positive receiving Aromatase Inhibitors, To assess cardiotoxicity in these patients, they were subjected to blood pressure and lipid profile measurement, electrocardiography (ECG), and electrocardiography (ECHO) and classified into patients had Nolvadex then A.I (arm 1) and others had upfront A.I (arm 2).Results: The age of patients ranged from 41 years to 85 years with mean age of 61 years. Seventy one patients (57.7%) showed cardiotoxicity as assessed by ECHO. They showed significant correlation with rising age above 62 years, IHD, history of HTN and DM (p value: .001, .001, .017 and 0.035 respectively). However, correlation between cardiotoxity and blood pressure changes, lipid profile changes and ECG findings and ECHO changes in switch therapy and upfront A.I were not statistically significant (p value = .275, .116, .081 and .761 respectively).Conclusion: Assessment of cardiotoxicity in hormone positive postmenopausal breast cancer patients receiving Aromatase Inhibitors showed evidence of cardiotoxicity in half the patients (57.7%) as detected by ECHO only. They showed statistically non significant correlations either recievied switch therapy or upfront A.I.


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