Lasofoxifene as a potential treatment for aromatase inhibitor-resistant ER-positive breast cancer.

BACKGROUND: Breast cancers treated with aromatase inhibitors (AIs) can develop AI resistance, which is often driven by estrogen receptor-alpha (ERα/ESR1) activating mutations, as well as by ER-independent signaling pathways. The breast ER antagonist lasofoxifene, alone or combined with palbociclib, elicited antitumor activities in a xenograft model of ER + metastatic breast cancer (mBC) harboring ESR1 mutations. The current study investigated the activity of LAS in a letrozole-resistant breast tumor model that does not have ESR1 mutations. METHODS: Letrozole-resistant, MCF7 LTLT cells tagged with luciferase-GFP were injected into the mammary duct inguinal glands of NSG mice (MIND model; 6 mice/group). Mice were randomized to vehicle, lasofoxifene ± palbociclib, fulvestrant ± palbociclib, or palbociclib alone 2-3 weeks after cell injections. Tumor growth and metastases were monitored with in vivo and ex vivo luminescence imaging, terminal tumor weight measurements, and histological analysis. The experiment was repeated with the same design and 8-9 mice in each treatment group. RESULTS: Western blot analysis showed that the MCF7 LTLT cells had lower ERα and higher HER2 expressions compared with normal MCF7 cells. Lasofoxifene ± palbociclib, but not fulvestrant, significantly reduced primary tumor growth versus vehicle as assessed by in vivo imaging of tumors at study ends. Percent tumor area in excised mammary glands was significantly lower for lasofoxifene plus palbociclib versus vehicle. Ki67 staining showed decreased overall tumor cell proliferation with lasofoxifene ± palbociclib. The lasofoxifene + palbociclib combination was also associated with significantly fewer bone metastases compared with vehicle. Similar results were observed in the repeat experiment. CONCLUSIONS: In a mouse model of letrozole-resistant breast cancer with no ESR1 mutations, reduced levels of ERα, and overexpression of HER2, lasofoxifene alone or combined with palbociclib inhibited primary tumor growth more effectively than fulvestrant. Lasofoxifene plus palbociclib also reduced bone metastases. These results suggest that lasofoxifene alone or combined with a CDK4/6 inhibitor may offer benefits to patients who have ER-low and HER2-positive, AI-resistant breast cancer, independent of ESR1 mutations.

Short Adult Height After Rapid-tempo Puberty: When is it too Late to Treat?

A rarely reported phenomenon of rapid-tempo puberty in which the physical changes of puberty and testosterone levels increase very rapidly has not been reported outside apart from in two reviews. The resulting rapid advancement of skeletal age causes early completion of growth with shorter adult stature than expected. This appears to be genetic given its occurrence in the present report in two families, one with three brothers, one with two. We also describe potential treatments and found for the youngest that early initiation of standard therapy preserved or reclaimed adult height (AH) potential. The foreshortened AH in this situation involves rapidly advancing puberty resulting from high circulating testosterone levels leading to rapid advance in skeletal age. This was recognized earlier among younger brothers and treatment with gonadotropin-releasing analogues, growth hormone (GH) and/or aromatase inhibitor therapy (AIT) was tried. Two brothers in family A and family B were treated. Case 5 started treatment early enough so his AH was within target height (mid-parental height) range. Cases 2, 3, 4 were tried on GH and/or AIT with outcomes suggesting benefit. The prevalence and mechanism of rapid-tempo puberty requires further study. Furthermore, as illustrated by two of the current cases, this phenomenon may have a heightened prevalence, or at least may occur, in children previously diagnosed with constitutional delay of growth, underscoring the need to be cautious in assurance of a normal AH outcomes in this population, based on data from a single assessment.

CDK4/6 Inhibitor Efficacy in ESR1-Mutant Metastatic Breast Cancer.

BACKGROUND: In estrogen receptor-positive metastatic breast cancer, ESR1 mutations (ESR1m) are a common mechanism of acquired resistance to aromatase inhibitors (ArIh). However, the impact ESR1 alterations have on CDK4/6 inhibitor (CDK4/6i) sensitivity has not been established. Analyses of CDK4/6i trials suggest that the endocrine therapy partner and specific ESR1 allele may affect susceptibility. We analyzed a real-world data set to investigate CDK4/6i efficacy in ESR1m metastatic breast cancer and associated clinical factors. METHODS: ESR1m were identified by analysis of circulating-tumor deoxyribonucleic acid. The GuardantINFORM database contains genomic information from tumors linked with claims data. Patients who started a CDK4/6i within 30 days of sequencing were categorized as having ESR1m or non-ESR1-mutant (non-ESR1m) breast cancer. Data were analyzed to determine the real-world time-to-next-treatment, defined as the start of a breast cancer treatment to initiation of the subsequent treatment. RESULTS: One hundred forty-five patients with ESR1m and 612 with non-ESR1m metastatic breast cancer were analyzed. ESR1m and non-ESR1m tumors had similar real-world time-to-next-treatment on CDK4/6i regimens (hazard ratio, 1.02; 95% confidence interval, 0.82 to 1.23). Duration on therapy in the first-line and second-line plus treatment settings were comparable regardless of ESR1 status. We stratified treatment duration by concurrent endocrine therapy, and patients with ESR1m had worse outcomes on ArIh but comparable real-world time-to-next-treatment on fulvestrant. CONCLUSIONS: These data suggest ESR1 variants are not associated with pan-CDK4/6i resistance and are consistent with the hypothesis that CDK4/6 blockade combined with a selective estrogen receptor degrader is potentially an effective option for ESR1m metastatic breast cancer.

Estrogen stimulates fetal vascular endothelial growth factor expression and microvascularization.

We recently showed that the ratio of capillaries to myofibers in skeletal muscle, which accounts for 80% of insulin-directed glucose uptake and metabolism, was reduced in baboon fetuses in which estrogen was suppressed by maternal letrozole administration. Since vascular endothelial growth factor (VEGF) promotes angiogenesis, the present study determined the impact of estrogen deprivation on fetal skeletal muscle VEGF expression, capillary development, and long-term vascular and metabolic function in 4- to 8-year-old adult offspring. Maternal baboons were untreated or treated with letrozole or letrozole plus estradiol on days 100-164 of gestation (term = 184 days). Skeletal muscle VEGF protein expression was suppressed by 45% (P < 0.05) and correlated (P = 0.01) with a 47% reduction (P < 0.05) in the number of capillaries per myofiber area in fetuses of baboons in which serum estradiol levels were suppressed 95% (P < 0.01) by letrozole administration. The reduction in fetal skeletal muscle microvascularization was associated with a 52% decline (P = 0.02) in acetylcholine-induced brachial artery dilation and a 23% increase (P = 0.01) in mean arterial blood pressure in adult progeny of letrozole-treated baboons, which was restored to normal by letrozole plus estradiol. The present study indicates that estrogen upregulates skeletal muscle VEGF expression and systemic microvessel development within the fetus as an essential programming event critical for ontogenesis of systemic vascular function and insulin sensitivity/glucose homeostasis after birth in primate offspring.

Identification of non-adherence to adjuvant letrozole using a population pharmacokinetics approach in hormone receptor-positive breast cancer patients.

BACKGROUND: Letrozole, an aromatase inhibitor metabolised via CYP2A6 and CYP3A4/5 enzymes, is used as adjuvant therapy for women with hormone receptor (HR)-positive early breast cancer. The objective of this study was to quantify the impact of CYP2A6 genotype on letrozole pharmacokinetics (PK), to identify non-adherent patients using a population approach and explore the possibility of a relationship between non-adherence and early relapse. METHODS: Breast cancer patients enrolled in the prospective PHACS study (ClinicalTrials.gov NCT01127295) and treated with adjuvant letrozole 2.5 mg/day were included. Trough letrozole concentrations (Css,trough) were measured every 6 months for 3 years by a validated LC-MS/MS method. Concentration-time data were analysed using non-linear mixed effects modelling. Three methods were evaluated for identification of non-adherent subjects using the base PK model. RESULTS: 617 patients contributing 2534 plasma concentrations were included and led to a one-compartment PK model with linear absorption and elimination. Model-based methods identified 28 % of patients as non-adherent based on high fluctuations of their Css,trough compared to 3 % based on patient declarations. The covariate analysis performed in adherent subjects revealed that CYP2A6 intermediate (IM) and slow metabolisers (SM) had 21 % (CI95 % = 12 - 30 %) and 46 % (CI95 % = 41 - 51 %) lower apparent clearance, respectively, compared to normal and ultrarapid metabolisers (NM+UM). Early relapse (19 patients) was not associated with model-estimated, concentration-based or declared adherence in the total population (p = 0.41, p = 0.37 and p = 0.45, respectively). CONCLUSIONS: These findings will help future investigations focusing on the exposure-efficacy relationship for letrozole in adjuvant setting.

Discovery of Novel ERα and Aromatase Dual-Targeting PROTAC Degraders to Overcome Endocrine-Resistant Breast Cancer.

Estrogen receptor α (ERα) plays a pivotal role in the proliferation, differentiation, and migration of breast cancer (BC) cells, and aromatase (ARO) is a crucial enzyme in estrogen synthesis. Hence, it is necessary to inhibit estrogen production or the activity of ERα for the treatment of estrogen receptor-positive (ER+) BC. Herein, we present a new category of dual-targeting PROTAC degraders designed to specifically target ERα and ARO. Among them, compound 18c bifunctionally degrades and inhibits ERα/ARO, thus effectively suppressing the proliferation of MCF-7 cells while showing negligible cytotoxicity to normal cells. In vivo, 18c promotes the degradation of ERα and ARO and inhibits the growth of MCF-7 xenograft tumors. Finally, compound 18c demonstrates promising antiproliferative and ERα degradation activity against the ERαMUT cells. These findings suggest that 18c, being the inaugural dual-targeting degrader for ERα and ARO, warrants further advancement for the management of BC and the surmounting of endocrine resistance.

Luteolin and its analog luteolin-7-methylether from Leonurus japonicus Houtt suppress aromatase-mediated estrogen biosynthesis to alleviate polycystic ovary syndrome by the inhibition of tumor progression locus 2.

ETHNOPHARMACOLOGICAL RELEVANCE: Leonurus japonicus Houtt (L. japonicus, Chinese motherwort), known as Yi Mu Cao which means "good for women", has long been widely used in China and other Asian countries to alleviate gynecological disorders, often characterized by estrogen dysregulation. It has been used for the treatment of polycystic ovary syndrome (PCOS), a common endocrine disorder in women but the underlying mechanism remains unknown. AIM OF THE STUDY: The present study was designed to investigate the effect and mechanism of flavonoid luteolin and its analog luteolin-7-methylether contained in L. japonicus on aromatase, a rate-limiting enzyme that catalyzes the conversion of androgens to estrogens and a drug target to induce ovulation in PCOS patients. MATERIALS AND METHODS: Estrogen biosynthesis in human ovarian granulosa cells was examined using ELISA. Western blots were used to explore the signaling pathways in the regulation of aromatase expression. Transcriptomic analysis was conducted to elucidate the potential mechanisms of action of compounds. Finally, animal models were used to assess the therapeutic potential of these compounds in PCOS. RESULTS: Luteolin potently inhibited estrogen biosynthesis in human ovarian granulosa cells stimulated by follicle-stimulating hormone. This effect was achieved by decreasing cAMP response element-binding protein (CREB)-mediated expression of aromatase. Mechanistically, luteolin and luteolin-7-methylether targeted tumor progression locus 2 (TPL2) to suppress mitogen-activated protein kinase 3/6 (MKK3/6)-p38 MAPK-CREB pathway signaling. Transcriptional analysis showed that these compounds regulated the expression of different genes, with the MAPK signaling pathway being the most significantly affected. Furthermore, luteolin and luteolin-7-methylether effectively alleviated the symptoms of PCOS in mice. CONCLUSIONS: This study demonstrates a previously unrecognized role of TPL2 in estrogen biosynthesis and suggests that luteolin and luteolin-7-methylether have potential as novel therapeutic agents for the treatment of PCOS. The results provide a foundation for further development of these compounds as effective and safe therapies for women with PCOS.

Progressive relaxation training in patients with breast cancer receiving aromatase inhibitor therapy-randomized controlled trial.

BACKGROUND: Aromatase inhibitors have positive impacts on the disease-free life of patients with breast cancer. However, their side effects, especially arthralgia, may be experienced by many patients. This study sought to assess the efficacy of Progressive Relaxation Exercises on the prevalent side effects of Aromatase Inhibitors in patients with breast cancer. MATERIALS AND METHODS: This clinical trial was conducted with single-blind randomization at a physiotherapy department in a local hospital. Patients who received Aromatase Inhibitor were assigned at random to either the study or control group. The study group (n = 22) performed a Progressive Relaxation Exercises program four days a week for six weeks, while the control group (n = 22) received advice on relaxation for daily life. Data was collected before the intervention and after six weeks. The study's primary endpoint was the Brief Pain Inventory, which was used to measure pain severity. Secondary endpoints included assessments of quality of life and emotional status, which were measured using the Functional Assessment of Chronic Illness Therapy and Hospital Anxiety and Depression scales, respectively. RESULTS: The study group exhibited a significant reduction in Pain Severity (p = 0.001) and Pain Interference (p = 0.012) sub-scores. Reduction in Pain Severity (p<0.001) and Patient Pain Experience (p = 0.003) sub-scores was also noted between the groups. Quality of Life and Emotional Status showed no significant variation both within and between the groups (p>0.05). CONCLUSION: The study demonstrated that Progressive Relaxation Exercises caused a significant reduction in pain scores among Breast Cancer patients receiving Aromatase Inhibitors. While a decrease in pain during the 6-week period is valuable data, it is necessary to monitor the long-term effects of relaxation techniques.

Real-World Evidence of Ribociclib Plus Aromatase Inhibitors as First-Line Treatment in Advanced Breast Cancer: The BrasiLEEira Study.

PURPOSE: Cyclin inhibitors plus endocrine therapy represent the reference standard for hormone receptor-positive (HR+)/human epidermal growth factor receptor 2-negative (HER2-) locally advanced or metastatic breast cancer (ABC). Efficacy results on hard end points such as overall survival come from well-designed randomized clinical trials (RCTs). However, a limitation of RCTs is the low external results validity, and their extrapolation to a broader population may not be appropriate. Real-world studies can overcome these limitations, also increasing the reliability of RCTs. MATERIALS AND METHODS: The BrasiLEEira was an observational, longitudinal, retrospective, multicenter study to evaluate the effectiveness and safety of ribociclib plus nonsteroidal aromatase inhibitors in Brazilian women age 18 years or older with HR+/HER2- ABC. The study was approved by the institutional review boards of all 11 hospitals. Data were collected anonymously from medical records using an electronic case report form designed by an independent academic research organization, which conducted the study considering all recommendations of international guidelines. The primary end point was 1-year progression-free survival (PFS) rate. Secondary end points included mortality, dose reduction, and safety. RESULTS: The mean age of 76 patients was 57 years, and 28.9% were Black/Brown. The most prevalent comorbidity was arterial hypertension (34.7%). About 26.0% had endocrine-resistant disease, and 54.1% had more than three metastatic sites. The PFS rate was 77.6%. Three patients died (3.9%). Dose reductions occurred in 37.7% of patients. The most common adverse event was neutropenia (68.4%). CONCLUSION: The high-quality evidence from the BrasiLEEira study corroborates the RCTs' findings, expanding its validity to a broader spectrum and underrepresented population who may benefit from ribociclib treatment.

Quantification of the aromatase inhibitor letrozole and its carbinol metabolite in mouse plasma by UHPLC-MS/MS.

A liquid chromatography - electrospray ionization-mass spectrometry (LC-ESI-MS) method was developed for the quantification of letrozole, a third-generation aromatase inhibitor, and its main carbinol metabolite (CM) in support of murine pharmacokinetic studies. Using polarity switching, simultaneous ESI-MS measurement of letrozole and CM was achieved in positive and negative mode, respectively. The assay procedure involved a one-step protein precipitation and extraction of all analytes from mouse plasma requiring only 5 µL of sample. Separation was optimized on an Accucore aQ column with gradient elution at a flow rate of 0.4 mL/min in 5 min. Two calibration curves per day over four consecutive measurement days showed satisfactory linear responses (r2 > 0.99) over concentration ranges of 5-1000 ng/mL and 20-2000 ng/mL for letrozole and CM, respectively. No matrix effect was found, and the mean extraction recoveries were 103-108 % for letrozole and 99.8-107 % for CM. Precision and accuracy within a single run and over four consecutive measurement days were verified to be within acceptable limits. Application of the developed method to preclinical pharmacokinetic studies in mice receiving oral letrozole at a dose 1 or 10 mg/kg revealed that the systemic exposure to letrozole was dose-, formulation-, and strain-dependent. These findings may inform the future design of preclinical studies aimed at refining the pharmacological profile of this clinically important drug.

Anastrozole monotherapy further improves near-adult height after the initial combined treatment with leuprorelin and anastrozole in early-maturing girls with compromised growth prediction: results from the second phase of the GAIL study.

Background: The first phase of the GAIL study ("Girls treated with an Aromatase Inhibitor and Leuprorelin," ISRCTN11469487) has shown that the combination of anastrozole and leuprorelin for 24 months is safe and effective in improving the predicted adult height (PAH) in girls with early puberty and compromised growth prediction by +1.21 standard deviation score (SDS; +7.51 cm) compared to inhibition of puberty alone, +0.31 SDS (+1.92 cm). Objectives and hypotheses: In the second phase of the GAIL study, we assessed the adult height (AH)/near-adult height (NAH) at the end of the first phase and, in addition, the efficacy of anastrozole monotherapy thereafter in further improving NAH. Methods: We measured the AH (age 16.5 years)/NAH [bone age (BA), 15 years] of the 40 girls included, divided into two matched groups: group A (20 girls on anastrozole + leuprorelin) and group B (20 girls on leuprorelin alone). Group A was further randomized into two subgroups: A1 and A2. Group A1 (n = 10), after completion of the combined therapy, received anastrozole 1 mg/day as monotherapy until BA 14 years, with a 6-month follow-up. Group A2 (n = 10) and group B (n = 20), who received only the combined treatment and leuprorelin alone, respectively, were recalled for evaluation of AH/NAH. Results: AH or NAH exceeded the PAH at the completion of the 2-year initial phase of the GAIL study in all groups, but the results were statistically significant only in group A1: NAH-PAH group A1, +3.85 cm (+0.62 SDS, p = 0.01); group A2, +1.6 cm (+0.26 SDS, p = 0.26); and group B, +1.7 cm (+0.3 SDS, p = 0.08). The gain in group A1 was significantly greater than that in group A2 (p = 0.04) and in group B (p = 0.03). Anastrozole was determined to be safe even as monotherapy in Group A1. Conclusions: In early-maturing girls with compromised growth potential, the combined treatment with leuprorelin and anastrozole for 2 years or until the age of 11 years resulted in a total gain in height of +9.7 cm when continuing anastrozole monotherapy until the attainment of NAH, as opposed to +7.4 cm if they do not continue with the anastrozole monotherapy and +3.6 cm when treated with leuprorelin alone. Thus, the combined intervention ends at the shortest distance from the target height if continued with anastrozole monotherapy until BA 14 years.

Drug-induced liver injury as assessed by the updated Roussel Uclaf Causality Assessment Method following mild COVID-19 in a patient under anastrozole therapy-A case report.

BACKGROUND: Anastrozole is a selective aromatase inhibitor used for the treatment of postmenopausal hormone-sensitive breast cancer. The major side effects include osteoporosis, hypercholesterolemia, and musculoskeletal events, such as arthralgia and myalgia. Other adverse events are rare, including symptoms of acne, masculinization, and drug-induced liver injury, with the latter reported in a few cases only. CASE: Here, we report on a patient under anastrozole therapy who developed drug-induced liver injury as assessed by the updated Roussel Uclaf Causality Assessment Method 5 weeks after a mild SARS-CoV-2 infection, which is, to the best of our knowledge, the first report of its kind involving anastrozole. Discontinuation of anastrozole resulted in a marked improvement of the alanine aminotransaminase, and aspartate aminotransaminase as well as normalized lactate dehydrogenase serum levels already seen after 26 days. Surprisingly, however, the cholestatic serum markers gamma-glutamyl transpeptidase and alkaline phosphatase showed a further rise, and took another 4 weeks to drop significantly. CONCLUSION: The presentation of this case is meant to alert physicians to a potential drug-induced liver injury following mild SARS-CoV-2 infection in patients under anastrozole medication.

Alteraciones cognitivas asociadas al tratamiento de hormonoterapia en pacientes con cáncer de mama: una revisión sistemática / Cognitive alterations associated with hormone therapy in patients with breast cancer: A systematic review

Objetivo: determinar las alteraciones cognitivas asociadas al tratamiento de hormonoterapia en pacientes con cáncer de mama. Método: el presente trabajo consiste en una revisión sistemática de estudios experimentales internacionales sobre los efectos de la hormonoterapia en las funciones cognitivas en mujeres con cáncer de mama, siguiendo la declaración PRISMA. Para su selección se han seguido unos criterios metodológicos estrictos, incluyendo únicamente estudios longitudinales con evaluaciones de línea base y/o grupo control. Resultados: a pesar de las discrepancias descritas, los resultados muestran deterioro significativo en memoria verbal, funciones ejecutivas, aprendizaje verbal y velocidad de procesamiento. Conclusiones: de cara a futuras investigaciones se recomienda utilizar unos criterios metodológicos más estrictos y realizar seguimientos a largo plazo, teniendo en cuenta que la media de administración de estos tratamientos oscila entre 5 y 10 años.(AU)

Objective: to determine the cognitive alterations associated with hormone therapy in breast cancer patients. Methods: the present work consists of a systematic review of international experimental studies on the effects of hormone therapy on cognitive functions in women with breast cancer, following the PRISMA statement. Strict methodological criteria were followed for its selection, including only longitudinal studies with baseline and/or control group evaluations. Results: despite the discrepancies described, the results show significant impairment in verbal memory, executive functions, verbal learning, and processing speed. Conclusions: for future research it is recommended to use stricter methodological criteria and to carry out long-term follow-ups, considering that the average time of administration of these treatments’ ranges between 5 and 10 year.(AU)

Effect of vitamin D in addition to letrozole on the ovulation rate of women with polycystic ovary syndrome: protocol of a multicentre randomised double-blind controlled trial.

INTRODUCTION: Low vitamin D status is prevalent among women with polycystic ovary syndrome (PCOS). The objective of the study is to assess the effect of vitamin D supplementation on (1) the ovulation rate to letrozole and (2) other reproductive, endocrine and metabolic outcomes after 1 year of supplementation in women with PCOS. METHODS AND ANALYSIS: This is a multicentre, randomised, double-blind, controlled clinical trial. A total of 220 anovulatory women with PCOS diagnosed by the Rotterdam criteria will be recruited. They will be randomly assigned to either the (1) vitamin D supplementation group or (2) placebo group. Those in the vitamin D group will take oral Vitamin D3 50 000 IU/week for 4 weeks, followed by 50 000 IU once every 2 weeks for 52 weeks. Those who remain anovulatory after 6 months will be treated with a 6-month course of letrozole (2.5 mg to 7.5 mg for 5 days per cycle titrated according to response) for ovulation induction. The primary outcome is the ovulation rate. All statistical analyses will be performed using intention-to-treat and per protocol analyses. ETHICS AND DISSEMINATION: Ethics approval was sought from the Institutional Review Board of the participating units. All participants will provide written informed consent before joining the study. The results of the study will be submitted to scientific conferences and peer-reviewed journals. TRIAL REGISTRATION NUMBER: NCT04650880.

Radiological, pathological and surgical outcomes after neoadjuvant endocrine treatment in patients with ER-positive/HER2-negative breast cancer with a clinical high risk and a low-risk 70-gene signature.

OBJECTIVE: This study aims to evaluate the response to and surgical benefits of neoadjuvant endocrine therapy (NET) in ER+/HER2-breast cancer patients who are clinically high risk, but genomic low risk according to the 70-gene signature (MammaPrint). METHODS: Patients with ER+/HER2-invasive breast cancer with a clinical high risk according to MINDACT, who had a genomic low risk according to the 70-gene signature and were treated with NET between 2015 and 2023 in our center, were retrospectively analyzed. RECIST 1.1 criteria were used to assess radiological response using MRI or ultrasound. Surgical specimens were evaluated to assess pathological response. Two breast cancer surgeons independently scored the eligibility of breast conserving therapy (BCS) pre- and post- NET. RESULTS: Of 72 included patients, 23 were premenopausal (100% started with tamoxifen of which 4 also received OFS) and 49 were postmenopausal (98% started with an aromatase inhibitor). Overall, 8 (11%) showed radiological complete response. Only 1 (1.4%) patient had a pathological complete response (RCB-0) and 68 (94.4%) had a pathological partial response (RCB-1 or RCB-2). Among the 26 patients initially considered for mastectomy, 14 (53.8%) underwent successful BCS. In all 20 clinical node-positive patients, a marked axillary lymph node was removed to assess response. Four out of 20 (20%) patients had a pathological complete response of the axilla. CONCLUSION: The study showed that a subgroup of patients with a clinical high risk and a genomic low risk ER+/HER2-breast cancer benefits from NET resulting in BCS instead of a mastectomy. Additionally, NET may enable de-escalation in axillary treatment.

Novel oral selective estrogen receptor degraders (SERDs) to target hormone receptor positive breast cancer: elacestrant as the poster-child.

INTRODUCTION: Estrogen receptor positive (ER+) breast cancer is the most common breast cancer subtype, and therapeutic management relies primarily on inhibiting ER signaling. In the metastatic setting, ER signaling is typically targeted by selective estrogen receptor degraders (SERDs) or aromatase inhibitors (AIs), the latter of which prevent estrogen production. Activating ESR1 mutations are among the most common emergent breast cancer mutations and confer resistance to AIs. AREAS COVERED: Until 2023, fulvestrant was the only approved SERD; fulvestrant is administered intramuscularly, and in some cases may also have limited efficacy in the setting of certain ESR1 mutations. In 2023, the first oral SERD, elacestrant, was approved for use in ESR1-mutated, ER+/HER2- advanced breast cancer and represents a new class of therapeutic options. While the initial approval was as monotherapy, ongoing studies are evaluating elacestrant (as well as other oral SERDs) in combination with other therapies including CDK4/6 inhibitors and PI3K inhibitors, which parallels the current combination uses of fulvestrant. EXPERT OPINION: Elacestrant's recent approval sheds light on the use of biomarkers such as ESR1 to gauge a tumor's endocrine sensitivity. Ongoing therapeutic and correlative biomarker studies will offer new insight and expanding treatment options for patients with advanced breast cancer.

Long-term effects of aromatase inhibitor withdrawal on bone mineral density in early breast cancer patients: 10-year follow-up results of the BREX study.

PURPOSE: We aimed to provide long-term bone mineral density (BMD) data on early breast cancer patients of the BREX (Breast Cancer and Exercise) study. The effects of exercise and adjuvant endocrine treatment 10 years after randomization were analyzed, with special emphasis on aromatase inhibitor (AI) therapy discontinuation at 5 years. METHODS: The BREX study randomized 573 pre- and postmenopausal breast cancer patients into a 1-year supervised exercise program or a control group. 372 patients were included into the current follow-up analysis. BMD (g/cm2) was measured by dual-energy X-ray absorptiometry at lumbar spine (LS), left femoral neck (FN), and the total hip. Separate groups were displayed according to baseline menopausal status, and whether the patient had discontinued AI therapy at 5 years or not. RESULTS: The BMD change from 5 to 10 years did not significantly differ between the two randomized arms. AI discontinuation at 5 years had statistically significant BMD effects. The FN BMD continued to decrease in patients who discontinued AI therapy during the first 5-year off-treatment, but the decrease was three-fold less than in patients without AI withdrawal (- 1.4% v. - 3.8%). The LS BMD increased (+ 2.6%) in patients with AI withdrawal during the first 5 years following treatment discontinuation, while a BMD decrease (-1.3%) was seen in patients without AI withdrawal. CONCLUSION: This study is to our knowledge the first to quantify the long-term impact of AI withdrawal on BMD. Bone loss associated with AI therapy seems partially reversible after stopping treatment. TRIAL REGISTRATION: http://www. CLINICALTRIALS: gov/ (Identifier Number NCT00639210).

Osteoporotic fracture risk in women with breast cancer treated with aromatase inhibitors: a health insurance claims database study in Japan.

BACKGROUND: Hormone therapy with aromatase inhibitors (AIs) for estrogen receptor-dependent breast cancer may expose patients to an increased osteoporosis risk. This study was performed to estimate fracture risk in women with breast cancer to whom AIs were prescribed in Japan. METHODS: This retrospective study used data from the Japanese Medical Data Vision database. Women with breast cancer prescribed AIs over a 12-month period were identified and matched to women not prescribed AIs using a propensity score. Fracture rates were estimated by a cumulative incidence function and compared using a cause-specific Cox hazard model. The proportion of women undergoing bone density tests was retrieved. RESULTS: For all fractures sites combined, cumulative fracture incidence at 10 years was 0.19 [95%CI: 0.16-0.22] in women prescribed AIs and 0.18 [95%CI: 0.15-0.21] without AIs. AI prescription was not associated with any changes in risk (adjusted hazard ratio: 1.08 [95%CI: 0.99-1.17] p = 0.08). Women prescribed AI more frequently underwent bone density testing (31.9% [95% CI: 31.2%; 32.6%] versus 2.2% [95% CI: 2.0%; 2.4%]). CONCLUSIONS: The anticipated association between AI exposure and osteoporotic fracture risk in Japanese women with breast cancer was not seen clearly.

Cost-effectiveness comparison of dalpiciclib and abemaciclib combined with an aromatase inhibitor as first-line treatment for HR+/HER2- advanced breast cancer.

OBJECTIVES: CDK4/6 inhibitors dalpiciclib and abemaciclib have been approved by the Chinese National Medical Products Administration as first-line treatment for postmenopausal females with hormone receptor-positive (HR+) and human epidermal growth factor receptor-2 negative (HER2-) advanced breast cancer (ABC). We aimed to assess the cost-effectiveness of dalpiciclib plus letrozole/anastrozole (non-steroidal aromatase inhibitor [NSAI]) compared with abemaciclib plus NSAI as a first-line treatment for HR+/HER2- ABC in China. METHODS: We constructed a Markov model with three health states to evaluate health and economic outcomes of first-line treatment with dalpiciclib plus NSAI and abemaciclib plus NSAI for HR+/HER2- ABC. Efficacy data was obtained from MONARCH3 and DAWNA-2 trials. Quality-adjusted life-years (QALYs) and incremental cost-effectiveness ratios (ICERs) were calculated. RESULTS: Compared with abemaciclib plus NSAI, dalpiciclib plus NSAI resulted in 4.27 additional QALYs, with an ICER of $14827.4/QALY. At a willingness-to-pay threshold of 3 times gross domestic product per capita in China for 2023 ($37721.5/QALY), the cost-effectiveness probability of dalpiciclib plus NSAI was 77.42%. CONCLUSIONS: From the perspective of Chinese payers, dalpiciclib plus NSAI appears to be a cost-effective strategy compared with abemaciclib plus NSAI for the first-line treatment of patients with HR+/HER2- ABC in China. CLINICAL TRIAL REGISTRATION: MONARCH3, www.clinicaltrials.gov, identifier is NCT02246621 and DAWNA-2, www.clinicaltrials.gov, identifier is NCT03966898.