P1, N=18, Recruiting, H. Lee Moffitt Cancer Center and Research Institute | Not yet recruiting --> Recruiting

No abstract available

P1, N=16, Completed, Stemline Therapeutics, Inc. | Recruiting --> Completed

We achieved a remarkable response in the metastatic lesions with minor toxicity issues. This case highlights the importance of utilizing up-to-date therapeutic agents and reactive decision-making during personalized cancer treatment.

Dose reduction of CDK4/6 inhibitors within the first 12 weeks of treatment was associated with significantly higher mortality and shorter treatment duration. These findings contrast with previous analyses showing no effect of dose reduction, likely due to considering immortal time bias in this study.

P1, N=18, Not yet recruiting, H. Lee Moffitt Cancer Center and Research Institute

P3, N=460, Not yet recruiting, Jiangsu Simcere Pharmaceutical Co., Ltd.

Depletion or inhibition of GPX4 increases sensitivity to palbociclib and giredestrant, and their combination, in ER+ breast cancer models, with GPX4 null xenografts being highly sensitive to palbociclib. Lipid peroxidation is promoted by a peroxisome AGPAT3-dependent pathway in ER+ breast cancer models, rather than the classical ACSL4 pathway. Our data demonstrate that CDK4/6 and ER inhibition creates vulnerability to ferroptosis induction, that could be exploited through combination with GPX4 inhibitors, to enhance sensitivity to the current therapies in breast cancer.

Pharmacologic targeting of estrogen signaling (either by HSD17B7 inhibition or with fulvestrant) and chemokine inflammation both decrease local E2 and prevent macrophage polarization. Overall, these findings suggest that chronic inflammation and hormonal disposition are critical contributors to the age-related nature of ER+ breast cancer development and growth and offer potential therapeutic insight to treat these patients. We uncover the unique underpinnings establishing how the systemic host environment contributes to the aged breast tumor microenvironment, characterized by high local estradiol and chronic inflammation with immune dysregulation, and show that targeting avenues of estrogen conversion and chronic inflammation work to restore anti-tumor immunity.

Camizestrant at 75 and 150 mg showed a significant benefit in progression-free survival versus fulvestrant. These results support further development of camizestrant for the treatment of oestrogen receptor-positive, HER2-negative breast cancer.

Fulvestrant (FUL), a selective estrogen receptor degrader used to treat AI-resistant ERα-positive postmenopausal BC, was found to induce degradation of ERα together with a decrease in ER-mediated transcription; however, FA2H protein expression and migration remained unchanged. Overall, the findings of this study suggest that FA2H is one of the drivers of LTED cell migration, and that LTED cells resistant to FUL therapy may be involved in malignancy and metastatic mechanisms.

P1, N=25, Not yet recruiting, University of Chicago

P3, N=4220, Recruiting, Stemline Therapeutics, Inc. | Not yet recruiting --> Recruiting

Imlunestrant, as monotherapy and combined with abemaciclib, has a manageable safety profile with preliminary evidence of antitumor activity in patients with ER+ EEC.

P2, N=30, Active, not recruiting, Hoffmann-La Roche | Recruiting --> Active, not recruiting

P1, N=10, Recruiting, Jiangsu Simcere Pharmaceutical Co., Ltd.

Estrogen receptor one (ESR1) gene mutations, driving resistance to aromatase inhibitors (AIs), may guide the use of fulvestrant or emerging oral selective estrogen receptor degraders (SERDs) like elacestrant. Targeting mutations like breast cancer gene 1 and 2 (BRCA 1/2) with Poly (ADP-ribose) polymerase (PARP) inhibitors or the PI3K/AKT/mTOR pathway provides therapeutic options. The advent of antibody-drug conjugates (ADCs) like trastuzumab deruxtecan (T-DXd) and novel agents targeting Trophoblast cell surface antigen-2 (Trop-2) introduces further complexity, underscoring the need for early intervention targeting specific genomic alterations in metastatic BC.

In this study, we employed formaldehyde cross-linking followed by ERα immunoprecipitation and mass spectrometry to reveal that fulvestrant, the first FDA-approved SERD, induces the interaction between ERα and SUMO E3 ligases PIAS1 and PIAS2. In addition, raloxifene (a SERM) and elacestrant (the first FDA-approved oral SERD) were identified as compounds that similarly induce ERα SUMOylation and inhibit its chromatin interaction. Our findings reveal a mechanism by which select ERα inhibitors disrupt ERα function through SUMOylation, offering insights for the development of next-generation ERα-targeted therapies.

HIF-1α induced ERβ gene transcription and protein expression in hypoxic cells via binding to HRE in the ESR2 promoter. The suppression of HIF-1α and ERβ both in vitro and in vivo effectively reduced the NSCLC tumor growth.

P3, N=320, Active, not recruiting, Genentech, Inc. | Recruiting --> Active, not recruiting | Trial primary completion date: Oct 2024 --> Mar 2026

P2, N=176, Recruiting, German Breast Group | Not yet recruiting --> Recruiting | Trial completion date: Mar 2028 --> Dec 2028 | Initiation date: Mar 2024 --> Oct 2024 | Trial primary completion date: Mar 2028 --> Dec 2028

In the liquid biopsies, we detected ESR1 mutations in 42 cases (25.9%) and ERBB2 mutations in six cases (3.7%), arguing for a change in therapy to fulvestrant, elacestrant, or neratinib. Furthermore, 17 cases had detectable TP53 mutations, associated with resistance against endocrine therapy. We conclude that liquid biopsy testing is a noninvasive, sensitive, and helpful method to optimize therapeutic decisions in metastatic BC.

In an analysis of tumor specimens from 32 patients, tumors exhibiting residual cell proliferation after aromatase inhibitor-induced estrogen deprivation with letrozole showed increased mitochondrial content...Pharmacological inhibition of complex I suppressed the tumor-forming potential of persisters and synergized with the anti-estrogen fulvestrant to induce regression of patient-derived xenografts...Endocrine-tolerant persister cancer cells that survive endocrine therapy can cause recurrent disease. Persister cells exhibit increased energetic dependence upon mitochondria for survival and tumor re-growth potential.

P3, N=500, Recruiting, AstraZeneca | Trial completion date: Jul 2030 --> Oct 2030

EMBER-2 combined with existing phase 1 data has identified 400mg as the optimal imlunestrant dose.

P3; Active, not recruiting --> Completed

The most interesting finding is that compound B16 exhibited significant degradation of ERα at 5 μM but didn't show antiproliferative activity at high concentrations in MCF-7 and T47D cells. Compound B16 may serve as an ER probe to investigate ER status in ER positive breast cancer cells.

P1, N=155, Recruiting, Olema Pharmaceuticals, Inc. | N=90 --> 155 | Trial completion date: Aug 2024 --> Jun 2026 | Trial primary completion date: Aug 2024 --> May 2026

Further biological studies revealed that A20 could degrade ERα through proteasome-mediated pathway, suppress signal transduction of MCF-7 cells, and arrest the cell cycle in G1 phase. Moreover, A20 showed excellent antitumor effect (TGI = 92.98 %, 30 mg kg-1 day-1) in the MCF-7 xenograft model in vivo with good safety and favorable pharmacokinetics (F = 39.6 %), making it a promising candidate for the treatment of breast cancer.

EGFR was among the VGLL1/TEAD-regulated genes, and VGLL1-directed EGFR upregulation sensitized fulvestrant-resistant breast cancer cells to EGFR inhibitors. Taken together, these findings identify VGLL1 as a transcriptional driver in ET resistance and advance therapeutic possibilities for relapsed ER+ breast cancer patients.

P1, N=24, Not yet recruiting, Shandong Suncadia Medicine Co., Ltd.

P3, N=312, Active, not recruiting, AstraZeneca | Recruiting --> Active, not recruiting

The presence of liver and bone metastases was associated with worse prognosis and survival; additionally, patients with worse performance status had shorter overall survival. These findings underscore the need for personalized therapies, opening new lines of future research.

This thermal analysis method was used as a surrogate for chromatography as a rapid, effective in-process check method for impurity quantitation to enable the timely release of the final reworked clinical batch. Post release, the % w/w oligomer value determined by calorimetry was in excellent agreement to that obtained by size exclusion chromatography.

P1, N=40, Recruiting, AstraZeneca | Not yet recruiting --> Recruiting

P1/2, N=528, Recruiting, Jiangsu HengRui Medicine Co., Ltd. | Not yet recruiting --> Recruiting

The results showed that all the compounds displayed good stability. Further, the ADMET results showed that compounds CID58023104 was observed to be deemed a hit compound; hence, CID58023104 and could be optimize, derivatize, and explore for further development as an anti-coronavirus agent targeting SARS-COV-2 main protease.

More recently, oral SERDs have been tested in patients with early hormone receptor positive breast cancer, although their impact on survival and in this curative setting compared to standard endocrine therapy still needs to be elucidated. The best timing and duration of SERD administration and specific biomarkers in (neo)adjuvant setting remain largely unknown.

Imlunestrant, as monotherapy or in combination with targeted therapy, had a manageable safety profile with evidence of preliminary antitumor activity in ER+/HER2- ABC.

Molecular profiling allowed the identification of ESR1Y537S, in an aggressive prolactinoma. ESR1Y537S was not detected early in the course of the disease and is likely conferring tumor aggressiveness. This finding emphasizes the significance of estrogen receptor signaling in prolactinomas. It also allowed the use of targeted therapy with successful control of disease progression.

EB1089 induced the expression of functional ERα in TNBC cells, restoring the antiproliferative effects of antiestrogens. These results highlight the potential of using EB1089 as a promising strategy for re-establishment of the antiproliferative effect of antiestrogens as a possible management for TNBC. This research lays the foundation for potential advancements in TNBC treatment, offering new avenues for targeted and effective interventions.

For patients with hormone receptor-positive/human epidermal growth factor receptor 2 (HER2)-negative (HR+/HER2-) metastatic breast cancer (mBC) progressed on first-line endocrine therapy plus a cyclin-dependent kinase 4 and 6 inhibitor (CDK4/6i), fulvestrant, a selective estrogen receptor degrader (SERD) administered intramuscularly, represented the only monotherapy option until the approval of elacestrant. However, in Europe, the access to this recommended drug depends on the decision of the National Health Authorities of each state. In this communication, we describe the main results and implications of the EMERALD trial, in the context of the biomarker-driven algorithm for patients with HR+/HER2- mBC progressed on CDK4/6i, and conclude that a subgroup of patients with ESR1-mutant tumors and specific clinical features can really derive a clinically meaningful benefit from elacestrant, sparing access to more toxic combination approaches and preserving the quality of life.