Efficacy Of Endocrine Therapy Research Articles

Association between endocrine adjuvant therapy intake timing and disease-free survival in patients with high-risk early breast cancer: results of a sub-study of the UCBG- UNIRAD trial

Circadian rhythms regulate cellular physiology and could influence the efficacy of endocrine therapy (ET) in breast cancer (BC). We prospectively tested this hypothesis within the UNIRAD adjuvant phase III trial (NCT01805271). 1278 patients with high-risk hormonal receptor positive (HR+)/HER2 negative (HER2-) primary BC were randomly assigned to adjuvant ET with placebo or everolimus. Patients prospectively reported in a diary the daily timing of ET intake among four 6-h slots (06:00-11:59 (morning), 12:00-17:59 (afternoon), 18:00-23:59 (evening), or 24:00-05:59 (nighttime). The association between ET timing and disease-free survival (DFS) was a prespecified secondary endpoint of the trial and the results of this observational study are reported here. ET timing was recorded by 855 patients (67.2%). Patients declaring morning (n=465, 54.4%) or afternoon (n=45, 5.4%) ET intake were older than those declaring evening (n=339, 39.6%) or nighttime (n=5, 0.6%) intake. With a median follow-up of 46.7 months, 118 patients had a local (n=30) or metastasis relapse (n=84), and 41 patients died. ET intake timing was not associated with DFS in the whole population (HR=0.77, 95% CI [0.53-1.12]). The association between ET intake timing and DFS according to the stratification factors revealed interactions with ET agent (tamoxifen versus Aromatase inhibitors (AI) with an increased DFS in the group of evening/nighttime versus morning/afternoon tamoxifen intake (HR=0.43, 95% CI [0.22-0.85]), while no association was found for AI intake (HR=1.07, 95% CI [0.68-1.69]). The interaction between ET intake timing and ET agent remained in multivariable analysis (HR=0.38 [0.16-0.91]). Tamoxifen intake in the evening/nighttime could be recommended in patients with high-risk HR+/HER2- BC while awaiting for results from further ET timing studies. UNIRAD was Supported by a grant from the French Ministry of Health PHRC 2012 and received funding from La Ligue contre le Cancer, Cancer Research-UK, Myriad Genetics, and Novartis.

Abstract PO1-02-04: The efficacy of endocrine therapy during the waiting period for surgery for hormone receptor-positive breast cancer

Abstract Background: Although neoadjuvant endocrine therapy has been used to improve breast conservation rate, its prognostic relevance is unknown. The search for a valid prognostic factor equivalent to pCR in neoadjuvant chemotherapy is a current challenge in neoadjuvant endocrine therapy. In this study, we investigated the efficacy of short term neoadjuvant endocrine therapy utilizing the waiting period for surgery and the prognostic factor including Preoperative Endocrine Prognostic Index (PEPI) score. Methods: A total of 480 patients with StageⅠ-Ⅲ hormone receptor-positive, HER2-negative breast cancer was treated with endocrine therapy during the waiting period for surgery between October 2012 and December 2021. Premenopausal and postmenopausal patients received tamoxifen (TAM) and non-steroidal aromatase inhibitor (AI), respectively. The primary endpoint was change in tumor size by ultrasound and Ki67 expression before and after short term endocrine therapy. The secondary endpoint was prognosis of patients divided by PEPI score which was calculated using tumor size, lymph node metastasis, Ki67 expression, and ER Allred score. This study was approved by the institutional review board of Teikyo University. Results: Median age and tumor size of the entire 480 patients was 55 years (range, 31 - 89), 1.65 cm (range, 0.4 – 7.5), respectively. The median duration of endocrine therapy was 39 days (range, 1-90). 19 (0.3 %) pts were clinically node-positive. Of the entire 480 patients, 211 and 269 patients had TAM and AI, respectively. After short term endocrine therapy, the tumor size was significantly reduced from 1.83cm to 1.62cm in AI group (p=0.02), although TAM did not decrease the tumor size (p=0.89). The Ki67 expression was significantly decreased from 16.4% to 11.3% in TAM group (p=0.002), and from 15.9% to 6.98% in AI group (p < 0.001). There were significant differences in the distribution of PEPI scores between TAM and AI group (p < 0.05) (Table). At the median follow-up of 1012 days, patients with PEPI score ≥ 4 showed worse disease-free survival compared with patients with PEPI score < 4 in TAM group (Figure1). Overall survival is not available because there were no deaths in TAM group. At the median observation period of 833 days, patients with PEPI score ≥ 4 showed worse disease-free survival compared with patients with PEPI score < 4 in AI group (Figure2). In terms of mortality, patients with PEPI score ≥ 4 had worse overall survival than patients with PEPI score 0 and 1-3 (p=0.07). Conclusions: These results suggested that neoadjuvant endocrine therapy during the waiting period for surgery might be effective in reducing Ki67 expression level and PEPI score might be useful in predicting the prognosis of hormone receptor positive breast cancer patients. Table. Distribution of PEPI score Figure 1. Disease-free survival in patients treated with tamoxifen Figure 2. Disease-free survival in patients treated with non-steroidal aromatase inhibitor Citation Format: Yuka Maeda, Saki Naruse, Yuka Isono, Ayana Sato, Akiko Matsumoto, Tatsuhiko Ikeda, Hiromitsu Jinno. The efficacy of endocrine therapy during the waiting period for surgery for hormone receptor-positive breast cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO1-02-04.

Abstract PO5-04-12: Comparison of chemotherapy efficacy in metastatic lobular vs. ductal breast cancer

Abstract Comparison of chemotherapy efficacy in metastatic lobular vs. ductal breast cancer Background: Invasive lobular carcinomas (ILC) are thought to be less chemo-sensitive than invasive ductal carcinomas (IDC), as reflected by lower rates of pathological complete response following neoadjuvant therapy. In the metastatic setting, evidence regarding chemotherapy (Cx) efficacy is limited. Methods: A retrospective review of prospectively collected data for consecutive patients (pts) with metastatic ILC (mILC) treated at a single institution between 2000 and 2023 was included. Pts with mILC were matched on a 1:2 ratio with a cohort of pts with metastatic IDC (mIDC) by age, era of diagnosis and initial metastatic burden. Primary outcome was efficacy of Cx in mILC vs. mIDC pts as measured by time to next treatment - TTNTc (months (m) between start date of first & second Cx). Key secondary endpoints included differences in efficacy of endocrine therapy between the two groups (as measured by TTNT and outcomes in pts with endocrine resistance (EnR) as defined by ESMO consensus guideline) and overall survival (time from diagnosis of metastatic breast cancer (BC) to death or last follow-up [OS]). Results: 376 pts were included, mILC (122) and mIDC (254) with median age 64y and 62y, respectively. A significantly higher proportion of mILC pts had hormone receptor positive/HER2 negative or lower proportion of triple negative disease (p< 0.0001). Compared to mIDC, mILC pts were more likely to have de novo disease (29% vs. 18%; p=0.02), lower grade (p< 0.0001), received endocrine therapy only (p=0.03) and were less likely to have visceral disease at diagnosis or any time after metastatic diagnosis (20% vs. 45% p< 0.0001, 35% vs. 51% < 0.0004, respectively). Median time to commencing chemotherapy from metastatic diagnosis was longer in mILC pts (5.8 v 2.0 m, p=0.03). There was no significant differences in TTNTc for patients with mILC and mIDC except for those with visceral disease at diagnosis (Table 1). There was no significant difference in TTNTc by histological subtype of mILC (p=0.46) or by choice of first line chemotherapy used (p=0.91). In the entire population, no significant OS difference observed in mILC and mIDC (Table 1). BC outcome was assessed in pts receiving endocrine therapy as first-line treatment (mILC 65, mIDC 102). There was no difference in TTNT (mILC 14.6m vs. mIDC 14.8m). There were no differences in incidence of EnR between the groups. OS was shorter in mILC pts with primary EnR. The presence of primary, secondary or no resistance within each histological group was significantly associated with OS (Table 1). Conclusion: Pts with mILC have a longer time to commencing chemotherapy, but efficacy of chemotherapy is similar to pts with mIDC; irrespective of lobular histologic subtype, first line chemotherapy regimen used and sites of disease, except for those mILC with visceral disease. There was no significant difference in OS between mILC and mIDC pts treated in this single centre study. Efficacy of endocrine treatment when given as first line treatment was similar in both groups with no significant difference when pts were evaluated by presence or absence of endocrine resistance, except for primary EnR, but pt numbers were small in this group. Our results demonstrate equivalent chemotherapy efficacy in pts with mILC as compared to mIDC.

Abstract PO2-06-06: Effectiveness and prognostic predictors of primary systemic therapy for de-novo Stage IV breast cancer - Supplementary analysis of JCOG1017 PRIM-BC

Abstract Background The optimal choice of drug is important in treating metastatic breast cancer, and the efficacy of the drug should be determined early, especially in cases of progression. On the other hand, untreated de novo Stage IV (dnST-IV) patients are expected to be more sensitive to drugs, but no detailed data are available. In JCOG1017 (Randomized trial of primary tumor resection in dnST-IV), dnST-IV patients were treated with primary systemic therapy for 3 months according to breast cancer subtypes before randomization. We already presented the results of primary endpoint. Primary tumor resection (PTR) could not significantly prolong the overall survival of de-novo stage IV breast cancer patients with sensitivity to primary systemic therapy. We conducted the supplementary analysis of JCOG1017 to clarify the efficacy of primary systemic therapy for dnST-IV and develop optimal treatment strategies for dnST-IV breast cancer. Methods In JCOG1017, systemic therapy was performed for each subtype/metastatic status as follows; 1) hormone therapy: ER+ HER2- and no life-threatening metastases, 2) weekly PTX therapy: life-threatening metastases, or ER-HER2-, 3) trastuzumab + pertuzumab + docetaxel (HPD) therapy OR trastuzumab + paclitaxel (HPTX) therapy: ER-HER2+. 4) hormone therapy: ER+HER2+ and no life-threatening metastases. The non-PD rate (no increase of more than 10% of the sum of the diameters of the target lesions compared before systemic therapy), the responses rate (cCR or cPR), and overall survival (OS) of responder (cCR or cPR)/non-responder (cSD or cPD) and PD/non-PD were examined. Results Among 569 patients who received primary systemic therapy in JCOG 1017, the non-PD rate was 77.2% and the response rate was 29.0% after 3 months of systemic therapy. By subtype, the non-PD rate was 78.2% for ER-HER2-, 75.4% for ER+HER2-, 92.9% for ER-HER2+, and 66.7% for ER+HER2+. The response rate was 36.4% for ER-HER2-, 13.4% for ER+HER2-, 81.0% for ER-HER2+, and 40.3% for ER+HER2+. In multivariable analysis, the non-PD rate was higher in postmenopausal (odds ratio [OR] 1.673, p=0.0240) and PgR-positive (OR 2.391, p= 0.0019) patients besides subtypes. Analysis results by drug were as follows; 1) hormone therapy (non-PD rate: 72.9%) was more effective for PgR-positive (OR 3.258, p< 0.0001), less effective for patients with visceral metastasis (OR 0.605, p=0.0334) and HER2-positive (OR 0.365, p=0.0016), 2) wPTX (non-PD rate: 76.1%) was no significant predictors of efficacy, 3) HPD/HPTX (non-PD rate: 92.7%) was more effective in patients with visceral metastasis (OR 15.818, p=0.0030). PD patients had much worse OS (hazard ratio [HR] 0.501, p< 0.0001) compared to non-PD, whereas responders had a little worse OS (HR 0.788, p=0.0538) compared to non-responders. Similar tendency was observed in any drug. Discussion Predictors of response to primary systemic therapy differed by subtype, with the need for treatment strategies tailored to PgR, HER2 expression, and the status of visceral metastasis. In the ER+HER2+ group, the efficacy of hormonal therapy alone was low, and combination therapy with molecular-targeted agents was considered necessary. The non-PD rate reflected prognosis in determining the efficacy of primary systemic therapy for dnST-IV. Citation Format: Tadahiko Shien, Akihiko Shimomura, Makoto Ishitobi, Kiyo Tanaka, Takahiro Tsukioki, Takashi Yamanaka, Fumitaka Hara, Kenjiro Aogi, Yasuhiro Yanagita, Michiko Tsuneizumi, Naohito Yamamoto, Hiroshi Matsumoto, Akihiko Suto, Ken-ichi Watanabe, Michiko Harao, Chizuko Kanbayashi, Mitsuya Ito, Keisei Anan, Shigeto Maeda, Keita Sasaki, Gakuto Ogawa, Haruhiko Fukuda, Hiroji Iwata. Effectiveness and prognostic predictors of primary systemic therapy for de-novo Stage IV breast cancer - Supplementary analysis of JCOG1017 PRIM-BC [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO2-06-06.

Abstract PO2-23-08: High intratumor heterogeneity induced PSME2 confers endocrine resistance via ERα PARylation in hormone receptor-positive and HER2-negative breast cancer

Abstract Background: Hormone receptor-positive and HER2-negative breast cancer, characterized by its significant intratumor heterogeneity (ITH), poses increased recurrence, metastasis risk, and endocrine resistance. A comprehensive understanding of the genomic and biological characteristics underlying ITH is crucial for the development of effective therapeutic strategies. Methods: We leveraged the multiomics data from our large cohort of 381 hormone receptor-positive and HER2-negative breast tumors, supplemented with single-cell sequencing (scRNA-seq) data from 9 individual samples, to investigate ITH and its associated molecular features. Mechanistic investigations were conducted using Stable Isotope Labeling by Amino Acids in Cell culture (SILAC) proteomics, co-immunoprecipitation (Co-IP), Chromatin Immunoprecipitation followed by quantitative PCR (ChIP-qPCR), and dual-luciferase reporter assays. We specifically focused on the role of Proteasome activator subunit beta (PSME2), a potential regulator of drug resistance and metastasis. Results: We quantified the degree of ITH at sample level using multi-omics and scRNA-seq data and observed a correlation between higher ITH levels, increased genomic instability, upregulation of the STING type-I-interferon-dependent pathway, and poor efficacy of endocrine therapy. Both bulk and single-cell data revealed an enrichment of PSME2, associated with type-I interferon, in groups exhibiting high ITH. Patients with elevated PSME2 expression manifested a poorer prognosis and diminished responsiveness to endocrine therapy. Within the context of ITH, we discovered that IFN-I transcriptionally activated PSME2 via STAT1. Further investigation revealed a complex interplay among PSME2, PARP1, and EWS, wherein PSME2-mediated degradation of EWS relieved the transcriptional repression of PARP1, resulting in its overexpression. This series of events, orchestrated by PSME2, led to ERα PARylation and promoted tamoxifen resistance. In subsequent clinical translation studies employing mouse xenograft, patient-derived organoid (PDO), and patient-derived xenograft (PDX) models, we demonstrated that PARP1 inhibitors could effectively mitigate tamoxifen resistance induced by high PSME2 expression, providing new insights into therapeutic strategies. Conclusions: Our study highlights the importance of understanding ITH in hormone receptor-positive and HER2-negative breast cancer and identifies PSME2 as a key player in endocrine resistance and patient prognosis. The application of PARP1 inhibitors shows promise in improving treatment outcomes in tumors with elevated ITH and PSME2 expression. Working Modle Citation Format: Li-Ping Ge, Zi-Yu Wang, Xi Jin, Yi-Zhou Jiang, Zhi-Ming Shao. High intratumor heterogeneity induced PSME2 confers endocrine resistance via ERα PARylation in hormone receptor-positive and HER2-negative breast cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO2-23-08.

Abstract PO5-01-12: Factors Influencing Late Recurrence in Breast Cancer: A Comprehensive Analysis of the Impact of Hormone Therapy Regimens

Abstract Late recurrence of breast cancer remains a significant challenge in patient management. Despite the established efficacy of hormone therapy, factors influencing late recurrence and the impact of different hormone therapy regimens on this outcome are not yet fully understood. This study aims to investigate the key determinants contributing to late recurrence within the context of different hormone therapy regimens. This study is a retrospective analysis of medical records from two institutions between 1988 and 2018, specifically examining patients who had HR-receptor positive breast cancer who underwent surgery and completed a 5-year course of standard hormone therapy. Primary endpoint is to identify the demographic, clinical and pathologic factors as associated with late recurrence. Out of 1929 eligible patients, 49.6% (956) received Tamoxifen (TMX), 37.6% (726) received Aromatase inhibitors (AI), and 12.8% (247) switched between regimens (TMX to AI or AI to TMX). Median follow-up was 12.1 years (3.75 - 21.41 years). During this period, all-type recurrence (ATR) occurred in 9.3% of all patients, with higher rates in the TMX recipients (12.2%). Locoregional and contralateral recurrence were identified in 10.6% of TMX recipients, 6.5% of patients who switched regimens, and 5% of AI recipients. In all patients, 5.4% were diagnosed with distant metastasis, with slightly higher rates in the TMX recipients (6.4%). Multiple sites in the bone, lung, liver and brain (34.3%) was the most prevalent location of distant metastasis (DM), followed by soft tissue (20%), liver (16.2%), bone (10.5%), lung (8.6%), and other locations. Significant differences in recurrence-free survival (RFS) were observed between hormone therapy groups (p=0.004, log-rank test). Mean overall RFS was 20.4 years (95% C.I. 20.1-20.9 years). TMX recipients had a mean RFS of 19.8 years, AI recipients had a mean RFS of 18.3 years and those who switched regimens had a mean RFS of 21.9 years. Further analysis showed premenopausal patients who switched regimens had higher RFS (p=0.014). No significant difference in RFS was seen between premenopausal patients receiving AI or Tamoxifen, or amongst post-menopausal patients with different hormone therapy regimens. No significant difference in distant metastasis-free survival (DMFS) was observed between hormone therapy groups (p=0.442). Mean overall DMFS was 21.5 years (95% C.I. 21.2 - 21.8 years), with TMX patients 21.1 years, AI patients at 18.6 years, and those who switched regimens at 21.4 years. Sub-analyses of DMFS in pre and postmenopausal patients with different hormone therapy regimens showed no significant differences. Multivariate analysis showed tumor size ≤ 2cm (p= 0.0001) and negative axillary node involvement (p= 0.0001) significantly decreased odds of developing late all-type recurrence (ATR) in TMX recipients. In patients who switched regimens, Her2 positivity (p=0.04) significantly decreased the odds of late ATR. In AI recipients, not undergoing axillary operation (p = 0.008) significantly increased the odds of late ATR. For TMX recipients, negative axillary node involvement (p=0.004), tumor size ≤ 2cm (p=0.03), and undergoing mastectomy (p=0.02) significantly decreased odds of distant metastasis (DM). Among patients who switched regimens, adjuvant anti-Her2 therapy (p=0.02) significantly decreased odds of DM. For AI recipients, high PR score (p=0.02) and undergoing sentinel lymph node biopsy significantly decreased odds of DM, while age < 50 years significantly increased odds of developing DM. These findings emphasize the significance of the relationship between hormone therapy regimens and factors affecting late recurrence, thereby providing valuable insights for clinical decision-making. Risk stratification based on identified factors can help in identifying patients at higher risk of late recurrence allowing for more intensive surveillance and potentially early intervention. Univariate (Chi-square, Logistic Regression) and Multivariate Analysis (Logistic Regression) for Clinicopathologic factors associated with all-type recurrence and distant metastasis after surgery and completion of 5-years endocrine therapy Table. a. LN lymph node b. SLNB, Sentinel lymph node biopsy c. ALND, Axillary lymph node dissection d. Cutoff values of Ki67 14% in KUAH and 10%in SNUH e. ER and PR cutoff value is 10% f. UV, Univariate analysis, MV multivariate analysis, O.R. Odds Ratio, C.I. Confidence Interval Citation Format: Mary Rose Mendoza, Eun-Shin Lee. Factors Influencing Late Recurrence in Breast Cancer: A Comprehensive Analysis of the Impact of Hormone Therapy Regimens [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO5-01-12.

Abstract 7613: Association of KAT6A expression with clinical outcomes in previously treated HR-positive and HER2-negative metastatic breast cancer

Abstract Background: KAT6A is a histone acetyltransferase that regulates gene transcription, cell cycle, senescence and cell differentiation. It is amplified and overexpressed in a subset of breast cancers and may positively regulate ER expression. Gene expression analysis in tumor samples from the PALOMA-3 study was conducted to explore potential associations of KAT6A and related biomarkers with enhanced benefit from the addition of palbociclib (PAL) to fulvestrant (FUL) in HR-positive, HER2-negative breast cancer. Methods: The PALOMA-3 trial randomly assigned 521 endocrine pretreated patients with metastatic breast cancer, including those with prior exposure to chemotherapy, to receive PAL+FUL or placebo (PBO) +FUL. Exploratory analysis was conducted on tumor gene expression levels of KAT6A and KAT6B to evaluate their association with the effect of PAL+FUL vs PBO+FUL on progression-free survival (PFS) using Cox proportional hazards regression analysis, with gene expression as a continuous variable or dichotomized by median. Treatment by biomarker interaction effect was also tested. Results: In the PALOMA-3 trial, the analyses were conducted in 214 patients (PAL+FUL, 137 patients; PBO+FUL, 77 patients) with baseline tissue profiled, which included 165 patients with prior chemotherapy (PAL+FUL, 101 patients; PBO+FUL, 64 patients). In patients with KAT6A data, a trend of better treatment effect (interaction p = 0.54) was observed in those with low KAT6A mRNA expression (median PFS on PAL+FUL was 11.04 months (m) and PBO+FUL was 3.65 m, HR = 0.52, 95% CI 0.32-0.85, log rank p = 0.008) versus high KAT6A expression (median PFS on PAL+FUL was 13.90 m and PBO+FUL was 11.20 m, HR = 0.66, 95% CI 0.39-1.13, p = 0.126). A treatment effect was observed in patients with prior exposure to chemotherapy who had low KAT6A expression (median PFS on PAL+FUL was 9.53 m and PBO+FUL was 3.66 m, HR = 0.55, 95% CI 0.33-0.94, p = 0.027), while this was not observed in those with high KAT6A expression (median PFS on PAL+FUL was 11.43 m and PBO+FUL was 11.33 m, HR = 1.13, 95% CI 0.61-2.09, p = 0.71), with the interaction p value of 0.12. No treatment difference was detected between treatment arms and expression levels of KAT6B (interaction p values of 0.48 and 0.36 in all patients and in those with prior chemo respectively). Potential interaction of KAT6A with other genes including ESR1 will be discussed. Conclusions: Low tumor KAT6A mRNA expression identified patients with relatively greater benefit from addition of PAL to FUL especially in those with prior exposure to both chemo- and endocrine therapies. The data support further investigation of KAT6A and its related biomarkers and their association with CDK4/6 inhibitors and/or endocrine therapy in HR+/HER2-breast cancer patients and to test if a KAT6 inhibitor can enhance CDK4/6 inhibitor and/or endocrine therapy efficacy in tumors with high KAT6A expression. Citation Format: Massimo Cristofanilli, Li Liu, Shibing Deng, Xin Huang, Fabrice André, Sibylle Loibl, Angela DeMichele, Eric Gauthier, Yuan Liu, Nicholas C. Turner. Association of KAT6A expression with clinical outcomes in previously treated HR-positive and HER2-negative metastatic breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7613.

Abstract 3572: Role of the gut microbiome in androgen production and prostate cancer treatment resistance

Abstract Metastatic prostate cancer is often treated via a combination of androgen deprivation therapy (ADT) and the androgen receptor axis-targeted therapies abiraterone acetate + prednisone (AA/P) or enzalutamide. Unfortunately, most individuals undergoing these treatments develop resistance, termed “castration resistance”, through an unknown mechanism. Previous studies demonstrate a potential link between the gut microbiota and the treatment efficacy of endocrine therapy in metastatic castration resistant prostate cancer (mCRPC). This may be due in part to gut bacterial communities with the machinery to synthesize androgens using mechanisms distinct from human cells. For example, the bacterial desAB genes (e.g., “desmolase”) that were first described in the gut commensal bacterial species Clostridium scindens convert cortisol and prednisone to the androgenic metabolites 11β-hydroxyandrost-4-ene-3,17-dione (11OHAD) and ∆1-adrenosterone (∆1-AT), respectively. We hypothesize that androgen synthesis by the gut microbiota promotes treatment resistance to AA/P in advanced prostate cancer. This study aims to determine if androgen-converting gut bacterial species as well as circulating and fecal androgen levels correlate with AA/P treatment response in individuals with mCRPC using a combination of metagenomics and metabolomics. We further aim to demonstrate the relationship between gut bacterial androgen production and prostate cancer treatment response using an in vivo mouse model. Metagenomic sequencing showed an imbalance in microbial communities and identified the presence of androgen-synthesizing bacteria such as C. scindens in fecal samples of individuals undergoing treatment with AA/P. We also demonstrate that the relative abundance of C. scindens, as well as other species reported to generate androgens, are significantly enriched during metastatic disease progression on AA/P. Furthermore, targeted quantitative PCR of the bacterial desmolase (desA) gene demonstrated that absolute levels of desmolase are significantly higher in AA/P non-responders relative to AA/P responders, and trended higher in individuals with rising prostate-specific antigen (PSA) versus stable PSA while on AA/P. Targeted LC/MS/MS analyses of fecal samples demonstrated the presence of testosterone, dihydrotestosterone, 11OHAD, ∆1-AT, and other androgen metabolites in association with rising PSA levels in the AA/P cohort. Furthermore, we demonstrate that C. scindens converts hydrocortisone and prednisone into 11OHAD and ∆1-AT, respectively, in vitro at 48- and 72h post-treatment, which recapitulates prior published studies. Finally, we have established a prostate cancer mouse model using a VCaP xenograft in which tumor growth was significantly inhibited by abiraterone acetate in comparison to treatment with ADT alone. Additional studies will use this mouse model to study the effects of androgen metabolism by gut bacteria on AA/P efficacy. Overall, this study ascertains the ability of the human gut microbiota to harbor androgen-synthesizing bacteria, which in turn can be an alternative source of androgens that could impact the efficacy of the anti-androgen therapies used to treat metastatic prostate cancer. Citation Format: Angelica I. Cruz Lebron, Pedro A. Balbuena-Almodóvar, Luke Mummert, Sarah Ernst, Mark Markowski, Michelle Rudek, Jason Ridlon, Karen S. Sfanos. Role of the gut microbiome in androgen production and prostate cancer treatment resistance [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3572.

Impact of HER2-low expression on the efficacy of endocrine therapy with or without CDK4/6 inhibitor in HR-positive/HER2-negative metastatic breast cancer: A prospective study.

CDK4/6 inhibitors in combination with traditional endocrine therapy (ET) have become the recommended first-line therapy for HR-positive/HER2-negative metastatic breast cancer (MBC). The aim of this prospective study was to evaluate the relationship between HER2-low expression and clinical outcomes in HR-positive/HER2-negative MBC patients receiving ET with or without CDK4/6 inhibitors. Between April 2016 and November 2019, 233 women with HR-positive/HER2-negative MBC who received ET with or without CDK4/6 inhibitors were enrolled into the study. The primary endpoint was progression-free survival (PFS). Statistical analysis included descriptive statistics, Kaplan-Meier curves, and Cox proportional hazards models. HER2-low and HER2-zero subgroups in the CDK4/6 inhibitor plus ET cohort showed no significant difference in the median PFS (10.9 vs. 8.0 months; hazard ratio: 0.92; 95% confidence interval [CI]: 0.64-1. 30; p = 0.65), while HER2-low subgroup showed a significantly shorter median PFS compared to the HER2-zero subgroup in the ET alone cohort (5.6 vs. 17.0 months; hazard ratio: 2.82; 95% CI: 1.34-5.93; p = 0.0044). Moreover, the objective response rate was significantly lower in the HER2-low subgroup than the HER2-zero subgroup in the ET alone cohort (10.5% vs. 40.0%, p = 0.047). Lastly, no significant difference was observed in the overall survival between the HER2-low and HER2-zero subgroups in both cohorts. This study suggested that HER2-low expression may predict the efficacy of ET but not that of CDK4/6 inhibitor plus ET in HR-positive/HER2-negative MBC patients. The results of this study highlight the importance of integrating HER2 status in tailoring personalized treatment strategies for HR-positive MBC.

Mammalian enabled protein enhances tamoxifen sensitivity of the hormone receptor-positive breast cancer patients by suppressing the AKT signaling pathway

BackgroundMammalian enabled (MENA) protein is a member of the enabled/vasodilator stimulated phosphoprotein (Ena/VASP) protein family, which regulates cytoplasmic actin network assembly. It plays a significant role in breast cancer invasion, migration, and resistance against targeted therapy and chemotherapy. However, its role in the efficacy of endocrine therapy for the hormone receptor-positive (HR+) breast cancer patients is not known. This study investigated the role of MENA in the resistance against tamoxifen therapy in patients with HR+ breast cancer and the underlying mechanisms.MethodsMENA expression levels in the clinical HR+ breast cancer samples (n = 119) were estimated using immunohistochemistry (IHC) to determine its association with the clinicopathological features, tamoxifen resistance, and survival outcomes. Western blotting (WB) and quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) analysis was performed to estimate the MENA protein and mRNA levels in the tamoxifen-sensitive and -resistant HR+ breast cancer cell lines. Furthermore, CCK8, colony formation, and the transwell invasion and migration assays were used to analyze the effects of MENA knockdown on the biological behavior and tamoxifen sensitivity of the HR+ breast cancer cell lines. Xenograft tumor experiments were performed in the nude mice to determine the tumor growth rates and tamoxifen sensitivity of the control and MENA knockdown HR+ breast cancer cells in the presence and absence of tamoxifen treatment. Furthermore, we estimated the growth rates of organoids derived from the HR+ breast cancer patients (n = 10) with high and low MENA expression levels when treated with tamoxifen.ResultsHR+ breast cancer patients with low MENA expression demonstrated tamoxifen resistance and poorer prognosis compared to those with high MENA expression. Univariate and multivariate Cox regression analysis demonstrated that MENA expression was an independent predictor of tamoxifen resistance in patients with HR+ breast cancer. MENA knockdown HR+ breast cancer cells showed significantly reduced tamoxifen sensitivity in the in vitro experiments and the in vivo xenograft tumor mouse model compared with the corresponding controls. Furthermore, MENA knockdown increased the in vitro invasion and migration of the HR+ breast cancer cells. HR+ breast cancer organoids with low MENA expression demonstrated reduced tamoxifen sensitivity than those with higher MENA expression. Mechanistically, P-AKT levels were significantly upregulated in the MENA-knockdown HR + breast cancer cells treated with or without 4-OHT compared with the corresponding controls.ConclusionsThis study demonstrated that downregulation of MENA promoted tamoxifen resistance in the HR+ breast cancer tissues and cells by enhancing the AKT signaling pathway. Therefore, MENA is a promising prediction biomarker for determining tamoxifen sensitivity in patients with HR+ breast cancer.

Breast density reduction as a predictor for prognosis in premenopausal women with estrogen receptor-positive breast cancer: an exploratory analysis of the updated ASTRRA study.

While the relationship between mammographic breast density reduction (MDR) and endocrine therapy efficacy has been reported in estrogen receptor (ER)-positive breast cancer, it is still unclear in premenopausal women, especially in the case of adding ovarian function suppression (OFS) to antihormone therapy. The authors investigated the impact of MDR on prognosis stratified by treatment based on the updated results of the ASTRRA trial. The ASTRRA trial, a randomized phase III study, showed that adding OFS to tamoxifen (TAM) improved survival in premenopausal women with estrogen receptor-positive breast cancer after chemotherapy. The authors updated survival outcomes and assessed mammography before treatment and the annual follow-up mammography for up to 5 years after treatment initiation. Mammographic density (MD) was classified into four categories based on the Breast Imaging-Reporting and Data System. MDR-positivity was defined as a downgrade in MD grade on follow-up mammography up to 2 years after randomization, with pretreatment MD grade as a reference. The authors evaluated MDR in 944 of the 1282 patients from the trial, and 813 (86.2%) had grade III or IV MD. There was no difference in the MDR-positivity rate between the two treatment groups [TAM-only group (106/476 (22.3%)) vs. TAM+OFS group (89/468 (19.0%)); P =0.217). MDR-positivity was significantly associated with better disease-free survival (DFS) in the TAM+OFS group (estimated 8-year DFS: 93.1% in MDR-positive vs. 82.0% in MDR-negative patients; HR: 0.37; 95% CI: 0.16-0.85; P =0.019), but not in the TAM-only group ( Pinteraction =0.039). MDR-positive patients who received TAM+OFS had a favorable DFS compared to MDR-negative patients who received only TAM (HR: 0.30; 95% CI: 0.13-0.70; P =0.005). Although the proportion of MDR-positive patients was comparable between both treatment groups, MDR-positivity was independently associated with favorable outcomes only in the TAM+OFS group.

Abstract A008: Toxic PARP trapping upon cAMP-induced DNA damage reinstates the efficacy of endocrine therapy and CDK4/6 inhibitors in treatment-refractory ER+ breast cancer

Abstract Estrogen receptor (ER)-positive (ER+) breast cancer has the highest incidence rate and accounts for around 75% of all cases. Endocrine therapy and CDK4/6 inhibitors are the standard of care (SOC) in ER+ breast cancer; however, resistance is common, and it greatly reduces patient survival. Therefore, elucidating the mechanisms of sensitivity and resistance to SOC therapy and identifying actionable targets are urgently needed. Here, we show that SOC therapy causes DNA damage and toxic PARP1 trapping upon generation of a functional BRCAness (i.e., BRCA1/2 deficiency) phenotype, leading to increased histone parylation and reduced H3K9 acetylation, resulting in transcriptional blockage and cell death. Mechanistically, SOC therapy downregulates phosphodiesterase 4D (PDE4D), a novel ER target gene in a feedforward loop with ER, resulting in increased cAMP, PKA-dependent phosphorylation of mitochondrial COXIV-I, ROS generation and DNA damage. However, during SOC resistance, an ER-to-EGFR switch induces PDE4D overexpression via c-Jun-mediated transcription. Importantly, we demonstrated that high PDE4D mRNA and protein expression is associated with dramatically worse disease-free survival and overall survival in endocrine therapy-treated ER+ breast cancer. Notably, combining SOC with inhibitors of PDE4D, EGFR or PARP1 overcomes SOC resistance irrespective of the BRCA1/2 status in multiple acquired SOC resistant cell line models, primary cultures and organoids of endocrine resistant ER+ PDXs in vitro and in vivo, providing actionable targets for restoring SOC efficacy. Considering the availability of potent and non-toxic PDE4D inhibitors, clinically approved EGFR and PARP1 inhibitors, our findings have great translational potential. Citation Format: Ozge Saatci, Mein Cetin, Meral Uner, Unal Metin Tokat, Ioulia Chatzistamou, Pelin Gulizar Ersan, Elodie Montaudon, Aytekin Akyol, Sercan Aksoy, Aysegul Uner, Elisabetta Marangoni, Mathew Sajish, Ozgur Sahin. Toxic PARP trapping upon cAMP-induced DNA damage reinstates the efficacy of endocrine therapy and CDK4/6 inhibitors in treatment-refractory ER+ breast cancer [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: DNA Damage Repair: From Basic Science to Future Clinical Application; 2024 Jan 9-11; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2024;84(1 Suppl):Abstract nr A008.

Insomnia and the menopause: Where are we and where are we going?

The menopause, marked by a decrease in ovarian follicles and changes in female sex hormones, can trigger symptoms such as facial flushing and sleep disturbances. Hormonal fluctuations, notably a decrease in estrogen and progesterone, are associated with night-time awakenings and difficulty maintaining uninterrupted sleep. This condition has a negative impact on quality of life, leading to conditions such as obesity, diabetes, cardiovascular disease, and depression. The transition to menopause intensifies sleep disorders, especially insomnia, which is often associated with hot flashes. Despite the lack of clear evidence on the efficacy of hormone therapy, its use persists, highlighting the need for personalized approaches. Therapeutic strategies, such as the fusion of hormone therapy with sleep hygiene and cognitive-behavioral therapy, are emerging as promising. Some recommendations include adjustments to sleep habits, regular exercise, and a balanced diet. In conclusion, menopause significantly influences sleep disorders in women, affecting various aspects of physical and emotional health. Comprehensive therapeutic strategies, including behavioral changes, hormone therapy, and nutritional support, show promise for improving quality of life during this inevitable transition in female aging.

Toxic PARP trapping upon cAMP-induced DNA damage reinstates the efficacy of endocrine therapy and CDK4/6 inhibitors in treatment-refractory ER+ breast cancer

Resistance to endocrine therapy and CDK4/6 inhibitors, the standard of care (SOC) in estrogen receptor-positive (ER+) breast cancer, greatly reduces patient survival. Therefore, elucidating the mechanisms of sensitivity and resistance to SOC therapy and identifying actionable targets are urgently needed. Here, we show that SOC therapy causes DNA damage and toxic PARP1 trapping upon generation of a functional BRCAness (i.e., BRCA1/2 deficiency) phenotype, leading to increased histone parylation and reduced H3K9 acetylation, resulting in transcriptional blockage and cell death. Mechanistically, SOC therapy downregulates phosphodiesterase 4D (PDE4D), a novel ER target gene in a feedforward loop with ER, resulting in increased cAMP, PKA-dependent phosphorylation of mitochondrial COXIV-I, ROS generation and DNA damage. However, during SOC resistance, an ER-to-EGFR switch induces PDE4D overexpression via c-Jun. Notably, combining SOC with inhibitors of PDE4D, EGFR or PARP1 overcomes SOC resistance irrespective of the BRCA1/2 status, providing actionable targets for restoring SOC efficacy.

Palbociclib: efficacy and safety in older patients

The development and introduction of cyclin-dependent kinases 4/6 (CDK4/6) inhibitors into clinical practice is one of the main achievements over the last 10 years in the treatment of metastatic breast cancer. All randomized trials demonstrated clinically significant efficacy of endocrine therapy plus CDK4/6 inhibitors in the first- and second-line therapy for hormone-dependent Her2-negative metastatic breast cancer. Three drugs are currently approved for this indication: palbociclib, ribociclib, and abemaciclib. Despite some differences in chemical, biological and pharmacological properties, as well as a range of incongruities between the patient populations enrolled in the clinical studies on the efficacy of various CDK4/6 inhibitors in the firstline therapy, all drugs showed a completely comparable improvement in progression-free survival with a hazard ratio of 0.5 regardless of previous treatments. Further traceability of the results and the accumulation of real-world clinical practice experience allowed to identify a potential difference not only in overall survival and the toxicity profiles, which are characteristic of each of the drugs, but also in the safety of use in patients of an older age group. As patients aged over 75 years are rarely enrolled in the clinical trials, the obtained results cannot be unequivocally extrapolated to this patient population, which is the decisive factor in determining the clinical experience value for an unselected patient population. The article considers clinical case reports of the use of palbociclib in the first-line therapy for hormone-dependent Her2-negative breast cancer in patients over 75 years of age with severe comorbidities.

PI3KCA mutation prevalence and outcome among patients with metastatic breast cancer in Bulgaria treated with first-line endocrine therapy.

e13005 Background: There are phosphatidylinositol-4,5-biphosphate 3-kinase catalytic subunit alpha ( PIK3CA) mutations in 30-40% of hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2) tumor samples. Nevertheless, clinical outcomes in this group vary amongst research trials. Methods: We sought to determine the incidence of PIK3CA mutations in Bulgarian patients with metastatic HR+, HER2-negative breast cancer, as well as to evaluate and compare progression-free survival (PFS) in the real world between wild-type (WT) and mutant cohorts. In this multicentric retrospective analysis, 250 tissue samples were collected between 2016 and 2022 from three Bulgarian oncology centers. Qualitative real-time PCR was used to determine the existence of PIK3CA mutations. The median follow-up time was 28 months. Results: The mean age was 57.6±11.6 years for the mutant cohort and 56.5±12.2 for the wild-type cohort (p=0.52). The percentage of patients with visceral metastatic disease was 58.8% (n=147). Postmenopausal patients were 84.3% (n=210). PIK3CA mutation prevalence was 29.2% (n=73). The most prevalent mutation was found in exon 20: H1047R (9.2%). Among all clinicopathological features, we observed only a significant relation between the presence of a mutation and a metastatic stage at diagnosis (p = 0.002). 67.1% of the patients received endocrine therapy (ET) + CDK4/6 inhibitor as first-line therapy, while the remainder receive ET monotherapy. Patients with PIK3CA mutation did not have significantly different median PFS compared to WT patients (32 months (95%, CI: 22-40) versus 24 months ((95%, CI: 21-36) (p=0.45)); HR=0.86 (95%, CI: 0.5-1.3) (p=0.46). In propensity matching score analysis (matched for treatment utilized as a first line ET, menopausal status, and locations of metastatic disease), we confirmed our finding (36 months (95%, CI: 20-40) versus 26 months (95%, CI: 21-38), p = 0.69). Conclusions: We demonstrated that the prevalence of PIK3CA mutations in Bulgarian patients is comparable to that reported in other countries. Our findings suggest that the presence of a PIK3CA mutation has no effect on the efficacy of endocrine therapy of first-line treatment. In summary, our study provides valuable insights into the topic, but limitations including the retrospective design and small sample size suggest that the findings need to be replicated by more robust studies and larger sample sizes to draw definitive conclusions.

Dalpiciclib in advanced breast cancer.

Hormone receptor-positive, HER2-negative advanced breast cancer is largely not curable. Anti-oestrogen agents improve the prognosis of patients with hormone receptor-positive, HER2-negative advanced breast cancer, but resistance eventually occurs. Targeting cyclin-dependent kinase 4 (CDK4) and CDK6 increases endocrine therapy efficacy, leading to the approval of CDK4/6 inhibitors palbociclib, ribociclib, and abemaciclib in the this treatment setting. 1 Spring LM Wander SA Andre F et al. Cyclin-dependent kinase 4 and 6 inhibitors for hormone receptor-positive breast cancer: past, present, and future. Lancet. 2020; 395: 817-827 Summary Full Text Full Text PDF PubMed Scopus (180) Google Scholar Dalpiciclib plus letrozole or anastrozole versus placebo plus letrozole or anastrozole as first-line treatment in patients with hormone receptor-positive, HER2-negative advanced breast cancer (DAWNA-2): a multicentre, randomised, double-blind, placebo-controlled, phase 3 trialOur findings suggest that dalpiciclib plus letrozole or anastrozole could be a novel standard first-line treatment for patients with hormone receptor-positive, HER2-negative advanced breast cancer, and is an alternative option to the current treatment landscape. Full-Text PDF

An increase in tumor-infiltrating lymphocytes after treatment is significantly associated with a poor response to neoadjuvant endocrine therapy for estrogen receptor-positive/HER2-negative breast cancers

BackgroundThe reason for the poor prognosis of estrogen receptor (ER) + /human epidermal growth factor receptor 2 (HER2)− breast cancer patients with high levels of tumor-infiltrating lymphocytes (TILs) is poorly understood. The association between TILs and response to neoadjuvant endocrine therapy (NET) was examined.MethodsWe recruited 170 patients with ER + /HER2− breast cancer who were treated with preoperative endocrine monotherapy. TILs were evaluated before and after NET, and their changes were noted. Furthermore, T cell subtypes were examined using CD8 and FOXP3 immunohistochemical analyses. Neutrophil and lymphocyte counts in the peripheral blood were analyzed with reference to TIL levels or changes. Responders were defined as Ki67 expression levels ≤ 2.7% after treatment.ResultsPost-treatment (p = 0.016), but not pre-treatment (p = 0.464), TIL levels were significantly associated with the response to NET. TIL levels increased significantly after treatment among non-responders (p = 0.001). FOXP3 + T cell counts increased significantly after treatment in patients with increased TILs (p = 0.035), but not in those without increased TILs (p = 0.281). Neutrophil counts decreased significantly after treatment in patients without increased TILs (p = 0.026), but not in patients with increased TILs (p = 0.312).ConclusionAn increase in TILs after NET was significantly associated with a poor response to NET. Given that FOXP3 + T-cell counts increased, and neutrophil counts did not decrease in patients with increased TILs after NET, the induction of an immunosuppressive microenvironment was speculated to play a role in the inferior efficacy. These data might partially indicate the involvement of the immune response in the efficacy of endocrine therapy.

Autophagy and Breast Cancer: Connected in Growth, Progression, and Therapy.

Despite an increase in the incidence of breast cancer worldwide, overall prognosis has been consistently improving owing to the development of multiple targeted therapies and novel combination regimens including endocrine therapies, aromatase inhibitors, Her2-targeted therapies, and cdk4/6 inhibitors. Immunotherapy is also being actively examined for some breast cancer subtypes. This overall positive outlook is marred by the development of resistance or reduced efficacy of the drug combinations, but the underlying mechanisms are somewhat unclear. It is interesting to note that cancer cells quickly adapt and evade most therapies by activating autophagy, a catabolic process designed to recycle damaged cellular components and provide energy. In this review, we discuss the role of autophagy and autophagy-associated proteins in breast cancer growth, drug sensitivity, tumor dormancy, stemness, and recurrence. We further explore how autophagy intersects and reduces the efficacy of endocrine therapies, targeted therapies, radiotherapy, chemotherapies as well as immunotherapy via modulating various intermediate proteins, miRs, and lncRNAs. Lastly, the potential application of autophagy inhibitors and bioactive molecules to improve the anticancer effects of drugs by circumventing the cytoprotective autophagy is discussed.

Efficacy of front-line treatment for hormone receptor-positive HER2-negative metastatic breast cancer with germline BRCA1/2 mutation.

Efficacy of endocrine therapy in HR+/HER2- metastatic breast cancer could differ depending on the presence of BRCA1/2 germline mutation. The ESME metastatic breast cancer platform (NCT03275311) is a French real world database. Multivariable models including a time-varying approach and landmark analyses assessed the association between time-dependent gBRCA status (categorised as gBRCAm, gBRCAwt (wild type), and untested), overall survival (OS), and first-line progression-free survival (PFS1). A total of 170 patients were gBRCAm carriers, 676 gBRCAwt, and 12,930 were untested at baseline. In the multivariable analysis, gBRCAm carriers overall had a lower OS compared to gBRCAwt (adjusted HR [95% CI] 1.26 [1.03-1.55]). gBRCAm patients treated with front-line endocrine therapy had lower adjusted OS (adjusted HR [95% CI] = 1.54 [1.03-2.32]) and PFS1 (adjusted HR [95% CI] 1.58 [1.17-2.12]) compared to gBRCAwt patients. However, for patients who received frontline chemotherapy, neither OS nor PFS1 differed between gBRCAm carriers and the other groups (HR versus gBRCAwt for OS: 1.12 [0.88-1.41], p = 0.350; PFS1: 1.09 [0.90-1.31], p = 0.379). In this large cohort of HR+/HER2- MBC patients treated in a pre-CDK4/6 inhibitors era, gBRCAm status was associated with a lower OS and lower PFS following first-line endocrine therapy, but not following first-line chemotherapy.