Long road towards effective HER3 targeting in breast cancer.

Breast cancer is a heterogeneous disease, encompassing multiple different subtypes. Thanks to the increasing knowledge of the diverse biological features of each subtype, most patients receive personalized treatment based on known biomarkers. However, the role of some biomarkers in breast cancer evolution is still unknown, and their potential use as a therapeutic target is still underexplored. HER3 is a member of the human epidermal growth factors receptor family, overexpressed in 50%-70% of breast cancers. HER3 plays a key role in cancer progression, metastasis development, and drug resistance across all the breast cancer subtypes. Owing to its critical role in cancer progression, many HER3-targeting therapies have been developed over the past decade with conflicting findings. Next-generation antibody-drug conjugates have recently shown promising results in solid tumors expressing HER3, including breast cancer. In this review, we discuss the HER3 role in the pathogenesis of breast cancer and its relevance across all subtypes. We also explore the new anti-HER3 treatment strategies, calling into question the significance of HER3 detection as crucial information in breast cancer treatment.

First-line real-world treatment patterns and survival outcomes in women younger or older than 40 years with metastatic breast cancer in the real-life multicenter French ESME cohort.

AIM: To describe first-line treatment patterns, overall survival (OS) and real-world progression-free survival (rwPFS) in young women (<40) with metastatic breast cancer (mBC), as compared to women aged 40-69. MATERIALS AND METHODS: Data on adult women diagnosed with mBC (2008-2017) were extracted from the ESME mBC database (NCT03275311) which includes consecutive patients starting first-line metastatic treatment in one of the 18 French Comprehensive cancer centers. We reported first-line therapeutic strategy and prognostic factors of OS and rwPFS for women aged < 40 and 40-69. RESULTS: In total, 14,897 mBC women were included (1512 aged <40). HR+ /HER2- mBC was the most frequent subtype. First-line treatment differed between young patients and older ones for HR+ /HER2- and Triple Negative (TN) mBC. Median OS for women aged < 40 and 40-69, respectively, was 46.9 and 46.2 months for HR+ /HER2- mBC; 13.5 and 15.2 for TN mBC; and, 60.7 and 55.1 for HER2 + mBC. Median rwPFS under first line treatment was 11.6 and 11.9 months for HR+ /HER2- in women aged < 40 and 40-69, respectively; 5.5 and 5.9 for TN, and, 13.3 and 12.9 for HER2 + . Factors associated with shorter OS and rwPFS were similar for both women aged < 40 and 40-69 and included ≥ 3 metastatic sites, visceral metastases, and longer MFI, with time-varying effects observed for several prognostic factors. CONCLUSION: Young women presented more frequently with TN and HER2 + subtypes and aggressive mBC than women aged 40-69 did. Prognostic factors of OS and rwPFS were quite similar between age groups and mBC subtypes.

Real-world clinical and survival outcomes of patients with early relapsed triple-negative breast cancer from the ESME national cohort.

BACKGROUND: Early metastatic relapse of triple-negative breast cancer (mTNBC) after anthracyclins and/or taxanes based (A/T) primary treatment represents a highly aggressive cancer situation requiring urgent characterisation and handling. Epidemio-Strategy-Medico-Economical-Metastatic Breast Cancer (ESME-MBC) database, a multicenter, national, observational cohort (NCT03275311) provides recent data on this entity. METHODS: All ESME patients diagnosed between 2008 and 2020 with mTNBC occurring as a relapse after a systemic neoadjuvant/adjuvant taxane and/or anthracycline-based chemotherapy were included. Early relapses were defined by a metastatic diagnosis up to 12 months of the end of neo/adjuvant A/T chemotherapy. We assessed overall survival (OS) and progression-free-survival under first-line treatment (PFS1) by early versus late relapse (≥12 months). RESULTS: Patients with early relapse (N = 881, 46%) were younger and had a larger tumour burden at primary diagnosis than those with late relapses (N = 1045). Early relapse rates appeared stable over time. Median OS was 10.1 months (95% CI 9.3-10.9) in patients with early relapse versus 17.1 months (95% CI 15.7-18.2) in those with late relapse (adjusted hazard-ratio (aHR): 1.92 (95% CI 1.73-2.13); p < 0.001). The median PFS1 was respectively 3.1 months (95% CI 2.9-3.4) and 5.3 months (95% CI 5.1-5.8); (aHR: 1.66; [95% CI 1.50-1.83]; p < 0.001). Among early relapsed patients, a higher number of metastatic sites, visceral disease but not treatment types, were independently associated with a poorer OS. CONCLUSION: These real-world data provide strong evidence on the dismal prognosis, higher treatment resistance and major unmet medical need associated with early relapsed mTNBC. Database registration: clinicaltrials.gov Identifier NCT032753.

Intracranial hypotension in a breast cancer patient treated with epidural blood patches.

We report the case of a patient with metastatic breast cancer who presented with an orthostatic headache. After a comprehensive diagnostic workup including MRI and lumbar puncture, we maintained the diagnosis of intracranial hypotension (IH). The patient was therefore treated with two consecutive non targeted epidural blood patches, resulting in the remission of IH symptoms for 6 months. IH in cancer patients is a rarer cause of headache than carcinomatous meningitis. As the diagnosis can be made by standard examination and the treatment is relatively simple and effective, IH deserves to be better known by oncologists.

Antibody-Drug Conjugate Revolution in Breast Cancer: The Road Ahead.

OPINION STATEMENT: Antibody drug-conjugates (ADCs) have revolutionized the treatment of many types of cancer, including breast cancer. Recently, two new ADCs have been approved, trastuzumab deruxtecan and sacituzumab govitecan; both have demonstrated impressive improvements in overall survival, trastuzumab deruxtecan in all three subtypes of metastatic breast cancer and sacituzumab govitecan in luminal and triple negative metastatic breast cancer. These drugs are the results of significant progress and innovation in the construction of the three components of an ADC, the monoclonal antibody, the payload, and the linker, and of the discovery of new target antigens. ADC engineering has profoundly changed the paradigm of cancer treatment, on one side being effective on tumors considered inherently resistant to the payload class of drugs and on the other side demonstrating activity in tumors with very low target expression. Yet, it is likely that we are just at the beginning of a new era as the identification of new targets and the introduction of new ADC constructs and combinations will expand the field of ADC rapidly over the coming years.

Efficacy of taxanes rechallenge in first-line treatment of early metastatic relapse of patients with HER2-negative breast cancer previously treated with a (neo)adjuvant taxanes regimen: A multicentre retrospective observational study.

BACKGROUND: Taxanes are one of the most effective chemotherapies (CT) in breast cancer (BC), but the efficacy of taxanes rechallenge in early metastatic relapse has been poorly studied in patients previously treated by taxanes in the (neo)adjuvant setting. Our study aimed to analyse the efficacy of taxane rechallenge in case of early metastatic relapse in a multicentre retrospective observational study compared with other chemotherapies. METHODS: We analysed the French national ESME metastatic BC (MBC) database and selected HER2- MBC patients who received CT in first-line treatment for a metastatic relapse occurring 3-24 months after previous (neo)adjuvant taxanes treatment. RESULTS: Of 23,501 female patients with MBC in ESME, 1057 met the selection criteria. 58.4% received a taxane-based regimen (75.4% concomitant bevacizumab) and 41.6% received other CT. In hormone-receptor positive (HR+)/HER2- MBC, multivariate analysis showed no difference in OS between taxanes without bevacizumab compared to other CT (HZR = 1.3 [0.97; 1.74], but taxanes was significantly associated with worse PFS (HZR = 1.48 [1.14; 1.93]). In TNBC, taxanes without bevacizumab and carboplatin/gemcitabine were not superior to other CT for OS (HZR = 1.07 [0.79; 1.44] and HZR = 0.81 [0.58; 1.13], respectively), while for PFS, taxanes was inferior (HZR = 1.33 [1.06-1.67]) and carboplatin plus gemcitabine was superior to other CT (HZR = 0.63 [0.46; 0.87]). For both subtypes, the worse outcome observed with paclitaxel was no longer observed with the addition of bevacizumab. CONCLUSIONS: With the limitation of retrospective design, taxanes rechallenge in early metastatic relapse of BC may result in a worse PFS in TNBC and HR+/HER2- MBC, which was not observed with the addition of bevacizumab.

[Mechanisms of resistance and escape to CAR-T cells]. / Mécanismes de résistance et d'échappement aux cellules CAR-T.

CAR-T cells represent a new approach to anti-tumor cellular immunotherapy allowing to combine the recognition of tumor antigens on target cells and the activation, proliferation and cytotoxic capacity of T lymphocytes. Impressive clinical results have been obtained with CAR-T cells targeting the CD19 antigen in relapsing or refractory B cell malignant lymphomas or acute lymphoblastic leukemias, with complete response rates of 40 to 90%. However, 30 to 50% of responding patients in B malignancies will escape treatment secondarily, and the effectiveness of these approaches in solid tumors remains limited. Different mechanisms of primary resistance and/or escape to CAR-T cells have been described. This review aims to describe these mechanisms and explore potential ways for optimization. We will see that the initial response and its long-term persistence depends on several parameters: the functional characteristics of the CAR-T cells in vivo, the expression of targeted antigens on tumor cells, the development of a immunosuppressive microenvironment. Or of an immune response directed against the CAR molecule. In solid tumors in particular, the specificity of the antigen target and the "homing" of CAR-T cells in the tumor site are additional elements to consider. A better knowledge of mechanisms of resistance will help to improve the clinical outcomes by either modulating the construction and the production of CAR-T cells and/or to combine them with other immunotherapeutic approaches to better control the tumor microenvironment.

Molecular Landscape of Therapy-related Myeloid Neoplasms in Patients Previously Treated for Gynecologic and Breast Cancers.

Definition of therapy-related myeloid neoplasms (TRMN) is only based on clinical history of exposure to leukemogenic therapy. No specific molecular classification combining therapy-related acute myeloid leukemia and therapy-related myelodysplastic syndromes has been proposed. We aimed to describe the molecular landscape of TRMN at diagnosis, among 77 patients with previous gynecologic and breast cancer with a dedicated next-generation sequencing panel covering 74 genes. We investigated the impact of clonal hematopoiesis of indeterminate potential-associated mutations (CHIP-AMs defined as presence at TRMN stage of mutations described in CHIP with a frequency >1%) on overall survival (OS) and the clinical relevance of a modified genetic ontogeny-based classifier that categorized patients in 3 subgroups. The most frequently mutated genes were TP53 (31%), DNMT3A (19%), IDH1/2 (13%), NRAS (13%), TET2 (12%), NPM1 (10%), PPM1D (9%), and PTPN11 (9%). CHIP-AMs were detected in 66% of TRMN patients, with no impact on OS. Yet, patients with CHIP-AM were older and had a longer time interval between solid tumor diagnosis and TRMN. According to our modified ontogeny-based classifier, we observed that the patients with TP53 or PPM1D mutations had more treatment lines and complex karyotypes, the "MDS-like" patients were older with more gene mutations, while patients with "De novo/pan-AML" mutations were younger with more balanced chromosomal translocations. Median OS within each subgroup was 7.5, 14.5, and 25.2 months, respectively, with statistically significant difference in multivariate analysis. These results support the integration of cytogenetic and molecular markers into the future TRMN classification to reflect the biological diversity of TRMN and its impact on outcomes.

Phenotypic discordance between primary and metastatic breast cancer in the large-scale real-life multicenter French ESME cohort.

Expression of hormone receptor (HR) for estrogens (ER) and progesterone (PR) and HER2 remains the cornerstone to define the therapeutic strategy for breast cancer patients. We aimed to compare phenotypic profiles between matched primary and metastatic breast cancer (MBC) in the ESME database, a National real-life multicenter cohort of MBC patients. Patients with results available on both primary tumour and metastatic disease within 6 months of MBC diagnosis and before any tumour progression were eligible for the main analysis. Among the 16,703 patients included in the database, 1677 (10.0%) had available biopsy results at MBC diagnosis and on matched primary tumour. The change rate of either HR or HER2 was 27.0%. Global HR status changed (from positive = either ER or PR positive, to negative = both negative; and reverse) in 14.2% of the cases (expression loss in 72.5% and gain in 27.5%). HER2 status changed in 7.8% (amplification loss in 45.2%). The discordance rate appeared similar across different biopsy sites. Metastasis to bone, HER2+ and RH+/HER2- subtypes and previous adjuvant endocrine therapy, but not relapse interval were associated with an HR discordance in multivariable analysis. Loss of HR status was significantly associated with a risk of death (HR adjusted = 1.51, p = 0.002) while gain of HR and HER2 discordance was not. In conclusion, discordance of HR and HER2 expression between primary and metastatic breast cancer cannot be neglected. In addition, HR loss is associated with worse survival. Sampling metastatic sites is essential for treatment adjustment.