Browsing by Subject "Aromatase inhibitors"

Now showing 1 - 7 of 7
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    Anastrozole has an association between degree of estrogen suppression and outcomes in early breast cancer and is a ligand for estrogen receptor α
    (American Association of Cancer Research, 2020-06-15) Ingle, James N.; Cairns, Junmei; Suman, Vera J.; Shepherd, Lois E.; Fasching, Peter A.; Hoskin, Tanya L.; Singh, Ravinder J.; Desta, Zeruesenay; Kalari, Krishna R.; Ellis, Matthew J.; Goss, Paul E.; Chen, Bingshu E.; Volz, Bernhard; Barman, Poulami; Carlson, Erin E.; Haddad, Tufia; Goetz, Matthew P.; Goodnature, Barbara; Cuellar, Matthew E.; Walters, Michael A.; Correia, Cristina; Kaufmann, Scott H.; Weinshilboum, Richard M.; Wang, Liewei; Medicine, School of Medicine
    Purpose: To determine if the degree of estrogen suppression with aromatase inhibitors (AI: anastrozole, exemestane, letrozole) is associated with efficacy in early-stage breast cancer, and to examine for differences in the mechanism of action between the three AIs. Experimental design: Matched case-control studies [247 matched sets from MA.27 (anastrozole vs. exemestane) and PreFace (letrozole) trials] were undertaken to assess whether estrone (E1) or estradiol (E2) concentrations after 6 months of adjuvant therapy were associated with risk of an early breast cancer event (EBCE). Preclinical laboratory studies included luciferase activity, cell proliferation, radio-labeled ligand estrogen receptor binding, surface plasmon resonance ligand receptor binding, and nuclear magnetic resonance assays. Results: Women with E1 ≥1.3 pg/mL and E2 ≥0.5 pg/mL after 6 months of AI treatment had a 2.2-fold increase in risk (P = 0.0005) of an EBCE, and in the anastrozole subgroup, the increase in risk of an EBCE was 3.0-fold (P = 0.001). Preclinical laboratory studies examined mechanisms of action in addition to aromatase inhibition and showed that only anastrozole could directly bind to estrogen receptor α (ERα), activate estrogen response element-dependent transcription, and stimulate growth of an aromatase-deficient CYP19A1-/- T47D breast cancer cell line. Conclusions: This matched case-control clinical study revealed that levels of estrone and estradiol above identified thresholds after 6 months of adjuvant anastrozole treatment were associated with increased risk of an EBCE. Preclinical laboratory studies revealed that anastrozole, but not exemestane or letrozole, is a ligand for ERα. These findings represent potential steps towards individualized anastrozole therapy.
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    Aromatase inhibitors augment nociceptive behaviors in rats and enhance the excitability of sensory neurons
    (Elsevier, 2016-07) Robarge, Jason D.; Duarte, Djane B.; Shariat, Behzad; Wang, Ruizhong; Flockhart, David A.; Vasko, Michael R.; Pharmacology and Toxicology, School of Medicine
    Although aromatase inhibitors (AIs) are commonly used therapies for breast cancer, their use is limited because they produce arthralgia in a large number of patients. To determine whether AIs produce hypersensitivity in animal models of pain, we examined the effects of the AI, letrozole, on mechanical, thermal, and chemical sensitivity in rats. In ovariectomized (OVX) rats, administering a single dose of 1 or 5mg/kg letrozole significantly reduced mechanical paw withdrawal thresholds, without altering thermal sensitivity. Repeated injection of 5mg/kg letrozole in male rats produced mechanical, but not thermal, hypersensitivity that extinguished when drug dosing was stopped. A single dose of 5mg/kg letrozole or daily dosing of letrozole or exemestane in male rats also augmented flinching behavior induced by intraplantar injection of 1000nmol of adenosine 5'-triphosphate (ATP). To determine whether sensitization of sensory neurons contributed to AI-induced hypersensitivity, we evaluated the excitability of neurons isolated from dorsal root ganglia of male rats chronically treated with letrozole. Both small and medium-diameter sensory neurons isolated from letrozole-treated rats were more excitable, as reflected by increased action potential firing in response to a ramp of depolarizing current, a lower resting membrane potential, and a lower rheobase. However, systemic letrozole treatment did not augment the stimulus-evoked release of the neuropeptide calcitonin gene-related peptide (CGRP) from spinal cord slices, suggesting that the enhanced nociceptive responses were not secondary to an increase in peptide release from sensory endings in the spinal cord. These results provide the first evidence that AIs modulate the excitability of sensory neurons, which may be a primary mechanism for the effect of these drugs to augment pain behaviors in rats.
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    Association of Variants in Candidate Genes with Lipid Profiles in Women with Early Breast Cancer on Adjuvant Aromatase Inhibitor Therapy
    (American Association for Cancer Research, 2016-03-15) Santa-Maria, Cesar A.; Blackford, Amanda; Nguyen, Anne T.; Skaar, Todd C.; Philips, Santosh; Oesterreich, Steffi; Rae, James M.; Desta, Zeruesenay; Robarge, Jason; Henry, Norah Lynn; Storniolo, Anna M.; Hayes, Daniel F.; Blumenthal, Roger S.; Ouyang, Pamela; Post, Wendy S.; Flockhart, David A.; Stearns, Vered; Medicine, School of Medicine
    Purpose: Aromatase inhibitors can exert unfavorable effects on lipid profiles; however, previous studies have reported inconsistent results. We describe the association of single-nucleotide polymorphisms (SNP) in candidate genes with lipid profiles in women treated with adjuvant aromatase inhibitors. Experimental design: We conducted a prospective observational study to test the associations between SNPs in candidate genes in estrogen signaling and aromatase inhibitor metabolism pathways with fasting lipid profiles during the first 3 months of aromatase inhibitor therapy in postmenopausal women with early breast cancer randomized to adjuvant letrozole or exemestane. We performed genetic association analysis and multivariable linear regressions using dominant, recessive, and additive models. Results: A total of 303 women had complete genetic and lipid data and were evaluable for analysis. In letrozole-treated patients, SNPs in CYP19A1, including rs4646, rs10046, rs700518, rs749292, rs2289106, rs3759811, and rs4775936 were significantly associated with decreases in triglycerides by 20.2 mg/dL and 39.3 mg/dL (P < 0.00053), respectively, and with variable changes in high-density lipoprotein (HDL-C) from decreases by 4.2 mg/dL to increases by 9.8 mg/dL (P < 0.00053). Conclusions: Variants in CYP19A1 are associated with decreases in triglycerides and variable changes in HDL-C in postmenopausal women on adjuvant aromatase inhibitors. Future studies are needed to validate these findings, and to identify breast cancer survivors who are at higher risk for cardiovascular disease with aromatase inhibitor therapy.
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    Associations between genetic variants and the effect of letrozole and exemestane on bone mass and bone turnover
    (SpringerLink, 2015-11) Oesterreich, Steffi; Henry, N. Lynn; Kidwell, Kelley M.; Van Poznak, Catherine H.; Skaar, Todd C.; Dantzer, Jessica; Li, Lang; Hangartner, Thomas N.; Peacock, Munro; Nguyen, Anne T.; Rae, James M.; Desta, Zeruesenay; Philips, Santosh; Storniolo, Anna M.; Stearns, Vered; Hayes, Daniel F.; Flockhart, David A.; Medicine, School of Medicine
    Adjuvant therapy for hormone receptor (HR) positive postmenopausal breast cancer patients includes aromatase inhibitors (AI). While both the non-steroidal AI letrozole and the steroidal AI exemestane decrease serum estrogen concentrations, there is evidence that exemestane may be less detrimental to bone. We hypothesized that single nucleotide polymorphisms (SNP) predict effects of AIs on bone turnover. Early stage HR-positive breast cancer patients were enrolled in a randomized trial of exemestane versus letrozole. Effects of AI on bone mineral density (BMD) and bone turnover markers (BTM), and associations between SNPs in 24 candidate genes and changes in BMD or BTM were determined. Of the 503 enrolled patients, paired BMD data were available for 123 and 101 patients treated with letrozole and exemestane, respectively, and paired BTM data were available for 175 and 173 patients, respectively. The mean change in lumbar spine BMD was significantly greater for letrozole-treated (-3.2 %) compared to exemestane-treated patients (-1.0 %) (p = 0.0016). Urine N-telopeptide was significantly increased in patients treated with exemestane (p = 0.001) but not letrozole. Two SNPs (rs4870061 and rs9322335) in ESR1 and one SNP (rs10140457) in ESR2 were associated with decreased BMD in letrozole-treated patients. In the exemestane-treated patients, SNPs in ESR1 (Rs2813543) and CYP19A1 (Rs6493497) were associated with decreased bone density. Exemestane had a less negative impact on bone density compared to letrozole, and the effects of AI therapy on bone may be impacted by genetic variants in the ER pathway.
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    Oral Endocrine Therapy Nonadherence, Adverse Effects, Decisional Support, and Decisional Needs in Women With Breast Cancer
    (Wolters Kluwer, 2018-01) Milata, Jennifer L.; Otte, Julie L.; Carpenter, Janet S.; School of Nursing
    BACKGROUND: Oral endocrine therapy (OET) such as tamoxifen or aromatase inhibitors reduces recurrence and mortality for the 75% of breast cancer survivors (BCSs) with a diagnosis of estrogen receptor-positive breast cancer. Because many BCSs decide not take OET as recommended because of adverse effects, understanding BCSs' decisional supports and needs is foundational to supporting quality OET decision making about whether to adhere to OET. OBJECTIVE: The aim of this study was to examine literature pertaining to OET nonadherence and adverse effects using the Ottawa Decision Support Framework categories of decisional supports and decisional needs because these factors potentially influence OET use. METHODS: A systematic literature search was performed in PubMed and CINAHL using combined search terms "aromatase inhibitors and adherence" and "tamoxifen and adherence." Studies that did not meet criteria were excluded. Relevant data from 25 publications were extracted into tables and reviewed by 2 authors. RESULTS: Findings identified the impact of adverse effects on OET nonadherence, an absence of decisional supports provided to or available for BCSs who are experiencing OET adverse effects, and the likelihood of unmet decisional needs related to OET. CONCLUSIONS: Adverse effects contribute to BCSs decisions to stop OET, yet there has been little investigation of the process through which that occurs. This review serves as a call to action for providers to provide support to BCSs experiencing OET adverse effects and facing decisions related to nonadherence. IMPLICATIONS FOR PRACTICE: Findings suggest BCSs prescribed OET have unmet decisional needs, and more decisional supports are needed for BCSs experiencing OET adverse effects.
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    Patient-Reported Outcomes and Early Discontinuation in Aromatase Inhibitor-Treated Postmenopausal Women With Early Stage Breast Cancer
    (Alphamed Press, 2016-05) Kadakia, Kunal C.; Snyder, Claire F.; Kidwell, Kelley M.; Seewald, Nicholas J.; Flockhart, David A.; Skaar, Todd C.; Desta, Zereunesay; Rae, James M.; Otte, Julie L.; Carpenter, Janet S.; Storniolo, Anna M.; Hayes, Daniel F.; Stearns, Vered; Henry, N. Lynn; Department of Medicine, School of Medicine
    BACKGROUND: Early discontinuation of aromatase inhibitors (AIs) is common and leads to poor outcomes but is challenging to predict. In the Exemestane and Letrozole Pharmacogenetics trial, a high rate of early discontinuation due to intolerance was observed. We hypothesized that early changes in patient-reported outcomes (PROs) predict AI discontinuation and that biochemical factors are associated with changes in PROs. PATIENTS AND METHODS: Postmenopausal women with early-stage breast cancer enrolled in a prospective randomized trial of exemestane versus letrozole completed questionnaires at baseline and serially over 24 months to assess overall quality of life (EuroQOL Visual Analog Scale [VAS]); mood; and multiple symptoms, including a musculoskeletal symptom cluster. A joint mixed-effects/survival model was used to estimate the effect of the change in PROs on AI discontinuation. Associations between biochemical factors and change in PROs were examined. RESULTS: A total of 490 patients were analyzed. Worsening of EuroQOL VAS and the musculoskeletal cluster were associated with the highest risk for early discontinuation (hazard ratio [HR], 2.77 [95% confidence interval (CI), 2.72-2.81; p = .015]; HR, 4.39 [95% CI, 2.40-8.02; p < .0001], respectively). Pharmacokinetics and estrogen metabolism were not consistently associated with change in PRO measures. No clinically significant differences in any PRO between AIs were observed. CONCLUSION: Changes in PROs early during AI therapy were associated with treatment discontinuation. Identification of these changes could be used to target interventions in patients at high risk for early discontinuation. IMPLICATIONS FOR PRACTICE: Early changes in patient-reported outcomes (PROs) can predict nonpersistence to aromatase inhibitor therapy. If used in clinical practice, PROs might identify women at highest risk for early discontinuation and allow for interventions to improve tolerance before significant toxicities develop. Further research is needed to improve capturing PROs in routine clinical practice.
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    Prospective assessment of patient-reported outcomes and estradiol and drug concentrations in patients experiencing toxicity from adjuvant aromatase inhibitors
    (SpringerLink, 2017-07) Kadakia, Kunal C.; Kidwell, Kelley M.; Seewald, Nicholas J.; Snyder, Claire F.; Storniolo, Anna Maria; Otte, Julie L.; Flockhart, David A.; Hayes, Daniel F.; Stearns, Vered; Henry, N. Lynn; Medicine, School of Medicine
    PURPOSE: Aromatase inhibitors (AI), which decrease circulating estradiol concentrations in post-menopausal women, are associated with toxicities that limit adherence. Approximately one-third of patients will tolerate a different AI after not tolerating the first. We report the effect of crossover from exemestane to letrozole or vice versa on patient-reported outcomes (PROs) and whether the success of crossover is due to lack of estrogen suppression. METHODS: Post-menopausal women enrolled on a prospective trial initiating AI therapy for early-stage breast cancer were randomized to exemestane or letrozole. Those that discontinued for intolerance were offered protocol-directed crossover to the other AI after a washout period. Changes in PROs, including pain [Visual Analog Scale (VAS)] and functional status [Health Assessment Questionnaire (HAQ)], were compared after 3 months on the first versus the second AI. Estradiol and drug concentrations were measured. RESULTS: Eighty-three patients participated in the crossover protocol, of whom 91.3% reported improvement in symptoms prior to starting the second AI. Functional status worsened less after 3 months with the second AI (HAQ mean change AI #1: 0.2 [SD 0.41] vs. AI #2: -0.05 [SD 0.36]; p = 0.001); change in pain scores was similar between the first and second AI (VAS mean change AI #1: 0.8 [SD 2.7] vs. AI #2: -0.2 [SD 2.8]; p = 0.19). No statistical differences in estradiol or drug concentrations were found between those that continued or discontinued AI after crossover. CONCLUSIONS: Although all AIs act via the same mechanism, a subset of patients intolerant to one AI report improved PROs with a different one. The mechanism of this tolerance remains unknown, but does not appear to be due to non-adherence to, or insufficient estrogen suppression by, the second AI.