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HER2-targeted therapies for patients with HER2 + breast cancer are rapidly evolving, offering a range of more complex and personalized treatment options. Currently, an array of anti-HER2 monoclonal antibodies, tyrosine kinase inhibitors and antibody-drug conjugates are administered, sometimes alongside chemotherapy or endocrine therapy, both in curative and palliative contexts. However, the heterogeneous nature of HER2 + breast cancer demands a deeper understanding of disease biology and its role in responsiveness to novel HER2-targeted agents, as well as non-HER2-targeted therapies, in order to optimize patient outcomes. In this Review, we revisit the mechanisms of action of HER2-targeted agents, examine the evidence supporting the use of dual HER2 blockade in patients with HER2-amplified tumours, and explore the role of biomarkers in guiding future treatment strategies. We also discuss potential implications for the future treatment of patients with HER2 + breast cancer., (© 2024. Springer Nature Limited.)

Background: The effect of the addition of cyclin-dependent kinases 4 and 6 inhibitors to endocrine therapy in terms of molecular downstaging remains undetermined. Switching from a high-risk to a low risk Recurrence Score (RS) group could provide useful information to identify patients who might not require chemotherapy. The purpose of this study was to assess the biological and clinical activity of letrozole plus palbociclib as neoadjuvant treatment for patients with hormone receptor (HR)-positive/human epidermal growth factor receptor 2 (HER2)-negative early breast cancer with an initial Oncotype DX RS ≥18., Patients and Methods: Participants were women aged ≥18 years with HR-positive/HER2-negative, Ki67 ≥ 20%, stage II-IIIB early breast cancer with a baseline RS ≥18. Eligible patients with a pretreatment RS 18-25 (cohort A) and 26-100 (cohort B) received six 28-day cycles of letrozole (2.5 mg per day; plus goserelin if pre- or perimenopausal) plus palbociclib (125 mg per day; 3/1 schedule) before surgery. The primary endpoint for both cohorts was the proportion of patients who achieved an RS ≤25 at surgery or a pathological complete response (pCR)., Results: A total of 67 patients were enrolled, among which 65 were assessable for the primary endpoint (32 patients in cohort A and 33 in cohort B). At surgery, 22 (68.8%) patients in cohort A and 18 (54.5%) patients in cohort B had an RS ≤25 or a pCR [only 1 (3.0%) patient in cohort B], meeting the primary endpoint in cohort B (P < 0.01), but not in cohort A (P = 0.98). No new safety signals were identified., Conclusions: The efficacy of neoadjuvant treatment with letrozole plus palbociclib does not seem to depend on pretreatment RS for patients with RS ≥18. However, around half of patients with HR-positive/HER2-negative early breast cancer with an RS 26-100 at baseline achieved molecular downstaging with this regimen., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Purpose: To evaluate the efficacy and safety of the combination of olaparib plus trastuzumab in patients with HER2-positive advanced breast cancer (ABC) and germinal BRCA mutations (gBRCAm)., Methods: OPHELIA (NCT03931551) was a single-arm, open-label, phase 2 clinical trial. Patients aged ≥18 years diagnosed with HER2-positive ABC with germinal deleterious mutations in BRCA1 or BRCA2 who had received at least one prior systemic regimen for advanced disease were enrolled. Patients received olaparib plus trastuzumab until disease progression, unacceptable toxicity, or consent withdrawal. The primary endpoint was investigator-assessed clinical benefit rate for at least 24 weeks as per RECIST v.1.1. Key secondary endpoints included overall response rate (ORR) and safety profile., Results: A total of 68 pre-treated HER2-positive ABC patients were screened. Due to slow accrual the trial was stopped after enrolling 5 patients instead of the planned sample size of 20. Four patients achieved clinical benefit (80.0 %, 95 % CI; 28.4-99.5, p < 0.001) and the primary endpoint was met. The ORR was 60.0 % (95 % CI; 14.7-94.7), including one complete response. Four (80.0 %) patients experienced at least one treatment-related treatment-emergent adverse event (TEAE). Most TEAEs were grade 1 or 2. There were no treatment-related deaths and no new safety signals were identified., Conclusions: This study suggests that the combination of olaparib plus trastuzumab may be effective and safe in pre-treated patients with HER2-positive gBRCAm ABC. This ABC patient population should be further studied and not be pre-emptively excluded from clinical trials of targeted therapy for BRCA1/2-driven cancers., Competing Interests: Declaration of competing interest J.E.A.M. reports receiving travel compensation from AstraZeneca, Roche; and research grants from AstraZeneca. J.B. has participated as invited speaker for AstraZeneca; has institutional, personal and financial interests in AstraZeneca; has institutional and other financial interests in AstraZeneca-MSD; has been involved in educational programs for AstraZeneca-MSD, declares participation in steering committees for AstraZeneca; reports institutional and financial interests in MEDSIR; and declares being a local principal investigator at MEDSIR. J.A.G.S. declares consultative and advisory services for Seagen, AstraZeneca, Daiichi Sankyo, Novaris, Gilead, Menarini; consultancy/speaker fees from Celgene, Eli Lilly, EISAI, MSD, Exact Sciences, Tecnofarma, Nolver (Adium), Asofarma, Roche; institution and research funding from AstraZeneca; and travel support from Gilead, AstraZeneca, Daiichi Sankyo. I.P. reports receiving honoraria from MSD, Novartis, AstraZeneca, Gildead; and consultancy or advisory role for AstraZeneca. M.F.A. declares speakers' bureaus from Daiichi-AstraZeneca, Lilly, Pfizer, Novartis, Eisai; expert testimony for Lilly; and receiving travel expenses from Roche, Novartis. B.B. reports receiving fees for medical education as consulting or advisory role with MSD, Roche, Pierre Fabre, Novartis, Astra Zeneca, Seagen; and speakers' bureau with Pfizer, Roche, MSD, Palex, Eisai, Daichii, Astra Zeneca, Seagen. M.H.L.C. reports speaker honoraria from Daichii, Novartis & Pierre Fabre; and travel and training grants from Roche, Pfizer, MSD & Novartis. J.P.E. is a full-time employee at MEDSIR. L.C. is a full-time employee at MEDSIR. M.S.C. reports participating in an advisory board for Optimapharm, Ability Pharma, and MD Anderson; and is a full-time employee at MEDSIR. J.M.P.G. declares having a consulting or advisory role for Lilly, Roche, Eisai, Daichii Sankyo, AstraZeneca, Seattle Genetics, Gilead, MSD; travel compensation from Roche; and employment at MEDSIR. J.C. reports serving as a consultant/advisor Roche, AstraZeneca, Seattle Genetics, Daiichi Sankyo, Lilly, Merck Sharp&Dohme, Leuko, Bioasis, Clovis Oncology, Boehringer Ingelheim, Ellipses, Hibercell, BioInvent, Gemoab, Gilead, Menarini, Zymeworks, Reveal Genomics, Scorpion Therapeutics, Expres2ion Biotechnologies, Jazz Pharmaceuticals, Abbvie, BridgeBio; receiving honoraria from Roche, Novartis, Eisai, Pfizer, Lilly, Merck Sharp&Dohme, Daiichi Sankyo, Astrazeneca, Gilead, Steamline Therapeutics; research funding to the Institution from Roche, Ariad pharmaceuticals, AstraZeneca, Baxalta GMBH/Servier Affaires, Bayer healthcare, Eisai, F.Hoffman-La Roche, Guardanth health, Merck Sharp&Dohme, Pfizer, Piqur Therapeutics, Iqvia, Queen Mary University of London; stock of MEDSIR, MAJ3 Capital, Leuko (relative); travel, accommodation, expenses from Roche, Novartis, Eisai, Pfizer, Daiichi Sankyo, Astrazeneca, Gilead, Merck Sharp&Dhome, Steamline Therapeutics; and patents: (1) Pharmaceutical Combinations of A Pi3k Inhibitor And A Microtubule Destabilizing Agent.Javier Cortés Castán, Alejandro Piris Giménez, Violeta Serra Elizalde. WO 2014/199294 A. ISSUED. (2) Her2 as a predictor of response to dual HER2 blockade in the absence of cytotoxic therapy.Aleix Prat, Antonio Llombart, Javier Cortés.US 2019/0338368 A1. LICENSED A.L.C. reports receiving research support from Roche, Agendia, Lilly, Pfizer, Novartis, Merck Sharp & Dohme, Gilead, and Daichii-Sanyo; consulting or advisory role for Lilly, Roche, Pfizer, and Novartis; speakers’ bureaus from Lilly, AstraZeneca, Merck Sharp & Dohme; travel support from Roche, Pfizer, AstraZeneca; and stock or other ownership of MEDSIR and Initia-Research. P.S.R., F.J.S.B., S.M., A.L.M., N.F., P.Z., T.D.R., and M.G. declare that they have not conflict of interest., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Purpose: Elacestrant significantly prolonged progression-free survival (PFS) with manageable safety versus standard-of-care (SOC) endocrine therapy (ET) in patients with estrogen receptor-positive (ER+), HER2- metastatic breast cancer and tumors harboring estrogen receptor 1 (ESR1) mutation following ET plus a cyclin-dependent kinase 4/6 inhibitor (ET+CDK4/6i). In patients with ESR1-mutated tumors, we evaluated the efficacy and safety of elacestrant versus SOC based on prior ET+CDK4/6i duration and in clinical subgroups with prior ET+CDK4/6i ≥12 months., Patients and Methods: EMERALD, an open-label phase III trial, randomly assigned patients with ER+, HER2- metastatic breast cancer who had received 1-2 prior lines of ET, mandatory CDK4/6i, and ≤1 chemotherapy to elacestrant (345 mg daily) or SOC (aromatase inhibitor or fulvestrant). PFS was assessed across subgroups in post hoc exploratory analyses without adjustment for multiple testing., Results: In patients with ESR1-mutated tumors and prior ET+CDK4/6i ≥12 months, the median PFS for elacestrant versus SOC was 8.6 versus 1.9 months (HR, 0.41; 95% confidence interval, 0.26-0.63). In this population, the median PFS (in months) for elacestrant versus SOC was 9.1 versus 1.9 (bone metastases), 7.3 versus 1.9 (liver and/or lung metastases), 9.0 versus 1.9 (<3 metastatic sites), 10.8 versus 1.8 (≥3 metastatic sites), 5.5 versus 1.9 (PIK3 catalytic subunit α mutation), 8.6 versus 1.9 (tumor protein p53 gene mutation), 9.0 versus 1.9 (HER2-low), 9.0 versus 1.9 (ESR1D538G-mutated tumors), and 9.0 versus 1.9 (ESR1Y537S/N-mutated tumors). Subgroup safety was consistent with the overall population., Conclusions: The duration of prior ET+CDK4/6i ≥12 months in metastatic breast cancer was associated with a clinically meaningful improvement in PFS for elacestrant compared with SOC and was consistent across all subgroups evaluated in patients with ER+, HER2-, ESR1-mutated tumors., (©2024 The Authors; Published by the American Association for Cancer Research.)

Purpose: The purpose of this study was to assess the predictive capability of HER2DX assay following (neo)adjuvant trastuzumab-pertuzumab (HP)-based therapy in HER2-positive (HER2+) early breast cancer., Experimental Design: HER2DX was analyzed in baseline pretreatment tumors from the PHERGain trial. Patients with stage I-IIIA HER2+ early breast cancer were randomized to group A [docetaxel, carboplatin, and HP (TCHP)] and group B (HP ± endocrine therapy). PET response was evaluated after two cycles. Group A received TCHP for six cycles regardless of PET response. Group B continued with HP ± endocrine therapy for six cycles (PET responders) or with TCHP for six cycles (PET nonresponders). The primary objective of this retrospective study was to associate the HER2DX pathologic complete response (pCR) score with pCR. The secondary objective was the association of the HER2DX risk score with 3-year invasive disease-free survival (iDFS)., Results: HER2DX was performed on 292 (82.0%) tumors. The overall pCR rate was 38.0%, with pCR rates of 56.4% in group A and 33.8% in group B. In multivariable analysis including treatment and clinicopathologic factors, the HER2DX pCR score (continuous variable) significantly correlated with pCR [OR, 1.29; 95% confidence interval (CI), 1.10-1.54; P < 0.001]. HER2DX-defined pCR-high, -med, and -low groups exhibited pCR rates of 50.4%, 35.8%, and 23.2%, respectively (pCR-high vs. pCR-low OR, 3.27; 95% CI, 1.54-7.09; P < 0.001). In patients with residual disease, the HER2DX high-risk group demonstrated numerically worse 3-year iDFS than the low-risk group (89.8% vs. 100%; HR, 2.70; 95% CI, 0.60-12.18; P = 0.197)., Conclusions: HER2DX predicts pCR in the context of neoadjuvant HP-based therapy, regardless of chemotherapy addition, and might identify patients at higher risk of recurrence among patients with residual disease., (©2024 The Authors; Published by the American Association for Cancer Research.)

Background: Trastuzumab deruxtecan (T-DXd) is approved for human epidermal growth factor receptor 2 (HER2)-positive and HER2-low advanced breast cancer (ABC). T-DXd has shown encouraging intracranial activity in HER2-positive ABC patients with stable or active brain metastases (BMs); however, its efficacy in patients with HER2-low ABC with BMs is not well established yet., Methods: DEBBRAH is a single-arm, five-cohort, phase II study evaluating T-DXd in patients with central nervous system involvement from HER2-positive and HER2-low ABC. Here, we report results from patients with heavily pretreated HER2-low ABC and active BMs, enrolled in cohorts 2 (n = 6, asymptomatic untreated BMs) and 4 (n = 6, progressing BMs after local therapy). Patients received 5.4 mg/kg T-DXd intravenously once every 21 days. The primary endpoint was intracranial objective response rate per Response Assessment in Neuro-Oncology Brain Metastases (RANO-BM) for both cohorts., Results: Intracranial objective response rate per RANO-BM was 50.0% [3/6 patients; 95% confidence interval (CI) 11.8% to 88.2%] and 33.3% [2/6 patients; 95% CI 4.3% to 77.7%; P = 0.033 (one-sided)] in cohorts 2 and 4, respectively. All responders had partial responses. Median time to intracranial response was 2.3 months (range, 1.5-4.0 months) and median duration of intracranial response was 7.2 months (range, 2.8-16.8 months). Median progression-free survival per RECIST v.1.1. was 5.4 months (95% CI 4.1-10.0 months). Treatment-emergent adverse events occurred in all patients included (16.7% grade 3). Three patients (25.0%) had grade 1 interstitial lung disease/pneumonitis., Conclusions: T-DXd demonstrated promising intracranial activity in pretreated HER2-low ABC patients with active BMs. Further studies are needed to validate these results in larger cohorts. This trial is registered with ClinicalTrials.gov, NCT04420598., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

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. This oral SERD has been approved for patients with ESR1-mutant HR+/HER2- mBC by the European Medicines Agency, the Food and Drug Administration, and the UK Medicines and Healthcare products Regulatory Agency, according to the results of the randomized phase III EMERALD trial, which demonstrated elacestrant superiority over standard endocrine monotherapy. Consequently, elacestrant has been incorporated in the European Society for Medical Oncology and American Society of Clinical Oncology guidelines. 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., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

The global phase 3 DESTINY-Breast03 study (ClinicalTrials.gov; NCT03529110) showed statistically significant and clinically meaningful improvements in progression-free survival (PFS) and overall survival (OS) with trastuzumab deruxtecan (T-DXd) over trastuzumab emtansine (T-DM1) in patients with human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer (mBC) previously treated with trastuzumab and a taxane. Here, we report a subgroup analysis of Asian patients enrolled in DESTINY-Breast03. In total, 309 patients (149 in the T-DXd arm and 160 in the T-DM1 arm) from Asian countries and regions were randomized. At data cutoff (July 25, 2022), the median duration of follow-up in the Asian subpopulation was 29.0 months with T-DXd and 26.0 months with T-DM1. The PFS (determined by blinded independent central review) hazard ratio was 0.30 (95% confidence interval 0.22-0.41) favoring T-DXd over T-DM1 (median PFS 25.1 vs. 5.4 months). Median OS was not reached in the T-DXd arm and was 37.7 months in the T-DM1 arm. The median treatment duration was 15.4 months with T-DXd and 5.5 months with T-DM1. The incidence of grade ≥3 drug-related treatment-emergent adverse events was similar between both treatment arms (49.0% vs. 46.5%) and was consistent with the overall DESTINY-Breast03 population. Adjudicated drug-related interstitial lung disease or pneumonitis occurred in 12.9% of patients treated with T-DXd and 2.5% treated with T-DM1, with a higher incidence in Japanese patients; none of these were grade ≥4 events. These efficacy and safety data reinforce the favorable benefit-risk profile of T-DXd in HER2-positive mBC, including in the Asian subgroup., (© 2024 The Author(s). Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.)

Purpose: This study aimed to investigate the current therapeutic management of patients with early-stage HER2-positive (HER2+) breast cancer in Spain, while also exploring the perceptions surrounding HER2DX in terms of its credibility, clinical relevance, and impact on therapeutic decision-making. Understanding these aspects is crucial for optimizing treatment strategies and enhancing patient outcomes in the context of HER2+ breast cancer., Methods: An online questionnaire was conducted by an independent third-party between April and May 2022 across 70 medical oncologists highly specialized in breast cancer management in Spain. The survey included 37 questions regarding treatment decision making in HER2+ early breast cancer., Results: The management of patients with HER2+ early breast cancer exhibited a high degree of heterogeneity. Among the interviewed oncologists, 53% would recommend upfront surgery for node negative tumors measuring 1 cm or less. Interestingly, 69% and 56% of interviewers were open to deescalate the duration of adjuvant trastuzumab in pT1a and pT1b N0 tumors, respectively. Certain clinicopathological characteristics, such as high grade, high Ki-67, and young age, influenced the decision to prescribe neoadjuvant treatment for patients with clinical stage 1 disease. In cases where neoadjuvant treatment was prescribed for cT1-2 N0 tumors, there was a wide variation in the choice of chemotherapeutic and anti-HER2 regimens. Regarding the use of adjuvant trastuzumab emtansine (T-DM1) in patients with residual disease after neoadjuvant therapy, there was diversity in practice, and a common concern emerged that T-DM1 might be overtreating some patients. HER2DX, as a diagnostic tool, was deemed trustworthy, and the reported scores were considered clinically useful. However, 86% of interviewees believed that a prospective trial was necessary before fully integrating the test into routine clinical practice., Conclusion: In the context of early-stage HER2+ breast cancer in Spain, a notable diversity in therapeutic approaches was observed. The majority of interviewed medical oncologists acknowledged HER2DX as a clinically valuable test for specific patients, in line with the 2022 SEOM-GEICAM-SOLTI clinical guidelines for early-stage breast cancer. To facilitate the full integration of HER2DX into clinical guidelines, conducting prospective studies to further validate its efficacy and utility was recommended., (© 2024. The Author(s).)

This manuscript describes the Advanced Breast Cancer (ABC) international consensus guidelines updated at the last two ABC international consensus conferences (ABC 6 in 2021, virtual, and ABC 7 in 2023, in Lisbon, Portugal), organized by the ABC Global Alliance. It provides the main recommendations on how to best manage patients with advanced breast cancer (inoperable locally advanced or metastatic), of all breast cancer subtypes, as well as palliative and supportive care. These guidelines are based on available evidence or on expert opinion when a higher level of evidence is lacking. Each guideline is accompanied by the level of evidence (LoE), grade of recommendation (GoR) and percentage of consensus reached at the consensus conferences. Updated diagnostic and treatment algorithms are also provided. The guidelines represent the best management options for patients living with ABC globally, assuming accessibility to all available therapies. Their adaptation (i.e. resource-stratified guidelines) is often needed in settings where access to care is limited., Competing Interests: Declaration of competing interest Matti S. Aapro: Consultant for Accord Pharmaceuticals, Amgen, BMS, Celgene, Clinigen Group, Daiichi Sankyo, Eisai Co.Ltd, Eli Lilly, Genomic Health (Exact Sciences), G1 Therapeutics, Inc., GlaxoSmithKline (GSK), Helsinn Healthcare SA, Hospira (Pfizer), Johnson & Johnson, Merck, Merck Serono (Merck KGaA), Mundipharma International Limited, Novartis, Pfizer, Pierre Fabre, Roche, Sandoz, Tesaro (GSK), Teva Pharmaceuticals Industries Ltd., Vifor Pharma. Received honoraria for lectures at symposia of Accord Pharmaceuticals, Amgen, Astellas, Bayer HealthCare Pharmaceuticals (Schering), Biocon, Boeringer Ingelheim, Cephalon, Chugai Pharmaceutical Co., Ltd., Daiichi Sankyo, Eisai Co., Ltd., Dr Reddy's Laboratories, Genomic Health (Exact Sciences), Glenmark Pharmaceuticals Limited, GSK, Helsinn Healthcare SA, Hospira (Pfizer), Ipsen, Janssen Biotech, Kyowa Kirin Group, Merck, Merck Serono (Merck KGaA), Mundipharma International Limited, Novartis, Pfizer, Pierre Fabre, Roche, Sandoz, Sanofi, Tesaro (GSK), Taiho Pharmaceutical, Teva Pharmaceutical Industries Ltd., Vifor Pharma. Grant/Research supports: Amgen, Eisai, Genomic Health (Exact Sciences), Helsinn, Hospira, Novartis, Merck, Mundipharma, Pfizer, Roche, Sandoz, Tesaro, Teva, Vifor. Jyoti Bajpai: Institutional financial interests for conducting research: Eli Lilly, MSD, Novartis, Roche, Paxman Coolers Ltd, Samsung Bioepis co. Ltd, Sun Pharma. Carlos H. Barrios: Receipt of grants/research supports: (to the institution) Nektar, Pfizer, Polyphor, Amgen, Daiichi Sankyo, Sanofi, Exelixis, Regeneron, Novartis, GSK, Janssen, OBI Pharma, Lilly, Seagen, Roche, BMS, MSD, Merck Serono, AstraZeneca, Novocure, Aveo Oncology, Takeda, TRIO, PharmaMar, Celgene, PPD, Syneos Health, Labcorp, ICON, IQVIA, Parexel, Nuvisan, PSI, Worldwide, Gilead Sciences, Bayer, Servier. Receipt of honoraria or consultation fees: Advisory Boards and Consulting: Boehringer-Ingelheim, GSK, Novartis, Pfizer, Roche/Genentech, Eisai, Bayer, MSD, AstraZeneca, Zodiac, Lilly, Sanofi, Daiichi. Stock shareholder: Ownership or stocks: Tummi, MEDSir. Jonas Bergh: Receipt of grants/research supports: Research grants from Amgen, AstraZeneca, Bayer, Merck, Pfizer, Roche & Sanofi-Aventis to Karolinska Institutet and/or University Hospital. No personal payments. Other support: Payment for a chapter in UpToDate on breast cancer prediction to Asklepios Medicin HB. Laura Biganzoli: Personal financial interests (Honoraria, consultancy or advisory role): Amgen, AstraZeneca, Boehringer-Ingelheim, Daiichi-Sankyo, Eisai, Exact Sciences, Gilead, Lilly, Menarini, Novartis, Pfizer, Pierre Fabre, Roche, Sanofi, SeaGen. Institutional financial interests: Celgene, Genomic Health, Novartis. Travel grants: AstraZeneca, Daiichi-Sankyo. Fatima Cardoso: Receipt of honoraria or consultation fees: Amgen, Astellas/Medivation, AstraZeneca, Celgene, Daiichi-Sankyo, Eisai, GE Oncology, Genentech, Gilead, GlaxoSmithKline, Iqvia, Macrogenics, Medscape, Merck-Sharp, Merus BV, Mylan, Mundipharma, Novartis, Pfizer, Pierre-Fabre, prIME Oncology, Roche, Sanofi, Samsung Bioepis, Seagen, Teva, Touchime. Maria-Joao Cardoso: Receipt of honoraria or consultation fees: AstraZeneca, Merck-Sharp, Novartis and Roche. Lisa A. Carey: Other support: Research funding (institution): NanoString Technologies, Seagen, Veracyte, AstraZeneca. Uncompensated relationships: Lilly, Seagen, Novartis, Genentech/Roche, GlaxoSmithKline. Mariana Chavez-MacGregor: Receipt of grants/research supports: BCRF, Susan G Komen. Receipt of honoraria or consultation fees: Astra Zeneca, Pfizer, Lilly, Roche, Merck. Javier Cortés: Receipt of grants/research supports: Roche, Celgene, Cellestia, AstraZeneca, Seattle Genetics, Daiichi Sankyo, Erytech, Athenex, Polyphor, Lilly, Merck Sharp&Dohme, GSK, Leuko, Bioasis, Clovis Oncology, Boehringer Ingelheim, Ellipses, Hibercell, BioInvent, Gemoab, Gilead, Menarini, Zymeworks, Reveal Genomics, Expres2ion Biotechnologies. Receipt of honoraria or consultation fees: Roche, Novartis, Celgene, Eisai, Pfizer, Samsung Bioepis, Lilly, Merck Sharp&Dohme, Daiichi Sankyo, Astrazeneca. Stock shareholder: MedSIR, Nektar Pharmaceuticals, Leuko (relative). Other support: Research funding to the Institution: Roche, Ariad pharmaceuticals, AstraZeneca, Baxalta GMBH/Servier Affaires, Bayer healthcare, Eisai, F.Hoffman-La Roche, Guardanth health, Merck Sharp&Dohme, Pfizer, Piqur Therapeutics, Puma C, Queen Mary University of London. Travel, accommodation, expenses: Roche, Novartis, Eisai, pfizer, Daiichi Sankyo, Astrazeneca, Gilead. Patents: Pharmaceutical Combinations of a Pi3k Inhibitor and A Microtubule Destabilizing Agent. Javier Cortés Castán, Alejandro Piris Giménez, Violeta Serra Elizalde. WO 2014/199294 A. ISSUED. Her2 as a predictor of response to dual HER2 blockade in the absence of cytotoxic therapy. Aleix Prat, Antonio Llombart, Javier Cortés.US 2019/0338368 A1. LICENSED. Giuseppe Curigliano: Receipt of grants/research supports: Merck. Receipt of honoraria or consultation fees: Merck, Lilly, Pfizer, Daichi Sankyo, Seagen, Novartis, Roche, Astra Zeneca, Ellipsis. Participation in a sponsored speakers' bureau: Seagen, Novartis, Lilly, Pfizer, Daichii Sankyo. Rebecca A. Dent: Receipt of grants/research supports: AstraZeneca, Roche. Receipt of honoraria or consultation fees: AstraZeneca, DKSH, Eisai, Merck, Novartis, Pfizer, Roche. Nagi S. El Saghir: Receipt of honoraria or consultation fees: Roche, Novartis, Lilly. Alexandru Eniu: Receipt of honoraria or consultation fees: Astra Zeneca, Daiichi Sankyo, Gilead, Janssen, MSD, Novartis, SeaGen. Receipt of grants/research supports: AstraZeneca. Full or part-time employment: European School of Oncology (ESO). Lesley Fallowfield: Receipt of grants/research supports: Novartis, Bristol-Myers Squibb, Lilly. Receipt of honoraria or consultation fees: Voluntis, Genomic Health, NanoString Technologies, Novartis, Pfizer, MSD, Novartis, Abbvie, Clovis Oncology, Puma Biotechnology, AstraZeneca, Takeda, Genomic Health/Exact Sciences, Lilly, Seagen, Roche. Sandra X. Franco Millan: Receipt of honoraria or consultation fees: Novartis, Pfizer, Eli Lilly. Participation in a sponsored speakers' bureau: Novartis, Pfizer, Eli Lilly. Karen Gelmon: Receipt of grants/research supports: Pfizer, AstraZeneca. Receipt of honoraria or consultation fees: Pfizer, Lilly, Novartis, AstraZeneca, Merck, Gilead, Seagen. Jenny Gilchrist: Receipt of honoraria or consultation fees: Eli-Lilly, AstraZeneca, Novartis, Pfizer, MSD, Gilead, Juniper Biologics. Joseph Gligorov: Receipt of grants/research supports: Eisai, Exact Science, Guardant, Roche Genentech. Receipt of honoraria or consultation fees: Astra Zeneca, Daiichi, Eisai, Evapharma, Exact Science, Gilead, Guardant Lilly, Merck, Novartis, Onxeo, Pfizer, Roche Genentech, Seattle Genetics. Participation in a sponsored speakers' bureau: Eisai, Eva Pharm, Novartis, Roche Genentech, Seattle Genetics. Other support (please specify): Institutional: Institut Universitaire de Cancérologie AP-HP Sorbonne Université; French breast cancer guidelines St Paul. Nadia Harbeck: Receipt of grants/research supports: all to institution. Receipt of honoraria or consultation fees: AstraZeneca, Daiichi-Sankyo, Gilead, Lilly, MSD, Novartis, PierreFabre, Pfizer, Roche, Sandoz, Seagen, Viatris, Zuelligpharma. Participation on a sponsored speakers' bureau: EPG Communication, MEDSCAPE, Springer. Stock shareholder: WSG minority ownership. Spouse/Partner: Consulting for WSG. Ranjit Kaur: Receipt of grants/research supports: Novartis, Roche, Pfizer, Astrazeneca. Receipt of honoraria or consultation fees: Novartis, Roche, Pfizer, Astrazeneca. Participation in a sponsored speakers' bureau: Novartis, Roche, Pfizer, Astrazeneca. Belinda Kiely: Receipt of honoraria or consultation fees: Speakers fees: Novartis, Eisai. Advisory boards: Roche, Gilead, Novartis. Other support (please specify): meeting registrations fees: Novartis, Pfizer, MSD. Sung-Bae Kim: Receipt of grants/research supports: Novartis, Sanofi-Aventis, and DongKook Pharm Co. Receipt of honoraria or consultation fees: Novartis, AstraZeneca, Lilly, Dae Hwa Pharmaceutical Co. Ltd, ISU Abxis, OBI pharma, Beigene and Daiichi-Sankyo. Stock shareholder: Genopeaks. Smruti Koppikar: Receipt of honoraria or consultation fees: Eli Lilly, Novartis, Cipla, Roche. Participation in a sponsored speakers' bureau: Eli Lilly, Novartis, Cipla, Roche. Marion Kuper-Hommel: Receipt of honoraria or consulting fees: Astra Zeneca. Ginny Mason: Participation in a sponsored speakers' bureau: Novartis. Volkmar Mueller: Receipt of grants/research supports: Institutional research support from Novartis, Roche, Seagen, Genentech, Astra Zeneca. Receipt of honoraria or consultation fees: Speaker honoraria: Astra Zeneca, Daiichi-Sankyo, Eisai, GSK, Pfizer, MSD, Medac, Novartis, Roche, Seagen, Onkowissen, high5 Oncology, Medscape, Gilead, Pierre Fabre. Consultancy honoraria from Roche, Pierre Fabre, Amgen, ClinSol, Novartis, MSD, DaiichiSankyo, Eisai, Lilly, Sanofi, Seagen, Gilead, Stemline, ClinSol. Other support (please specify): Travel grants: Roche, Pfizer, Daiichi Sankyo, Gilead. Claire Myerson: Receipt of honoraria or consultation fees: Novartis Pharma. Silvia Neciosup: Receipt of grants/research supports: Roche, Pfizer. Participation in a sponsored speakers' bureau: Tecnofarma, AZ, Roche, Pfizer. Larry Norton: Receipt of honoraria or consultation fees: Blackrock QLS Advisors, Cold Spring Harbor Laboratory, UNC Breast Spore EAB Meeting, Codagenix Scientific Advisory Board Meeting, Martell Diagnostic Laboratories, Inc., Celgene, Agenus, Immix Biopharma, Inc. Shinji Ohno: Participation in a sponsored speakers' bureau: Chugai, Lilly, MSD, Nippon Kayaku. Shani Paluch-Shimon: Receipt of grants/research supports: Pfizer. Receipt of honoraria or consultation fees: Pfizer, Lily, Novartis, Astra Zeneca, Roche, MSD, Gilead, Rhenium/Exact Sciences, Stemline, Daichi Sankyo. Participation in a sponsored speakers' bureau: Pfizer, Lily, Novartis, Astra Zeneca, Roche, MSD, Gilead. Ann H. Partridge: Uptodate Royalties. Aleix Prat: Receipt of grants/research supports: Boehringer, Novartis, Roche, Nanostring, Sysmex Europa GmbH, Medica Scientia inno. Research, SL, Celgene, Astellas and Pzifer. Receipt of honoraria or consultation fees: Roche, Pfizer, Novartis, Amgen, BMS, Puma, Oncolytics Biotech, MSD, Guardan Health, Peptomyc and Lilly, Nanostring Technologies and Daiichi Sankyo. Other support: Clinical trials: Boehringer, Lilly, Roche, Novartis, Amgen and Daiichi Sankyo. Hope S. Rugo: Receipt of grants/research supports: Astellas Pharma Inc.; AstraZeneca; Daiichi Sankyo, Inc.; F. Hoffmann-La Roche AG/Genentech, Inc.; Gilead Sciences, Inc.; GlaxoSmithKline; Lilly; Merck & Co., Inc.; Novartis Pharmaceuticals Corporation; Pfizer; Pionyr Immunotherapeutics; Sermonix Pharmaceuticals Inc.; Taiho Oncology, Inc. and Veru Inc. Receipt of honoraria or consultation fees: Puma, NAPO, Blueprint, and Scorpion Therapeutics Daichi Sankyo. Elzbieta Senkus: Receipt of honoraria or consultation fees: AstraZeneca, Curio Science, Egis, Eli Lilly, Gilead, high5md, MSD, Novartis, Pfizer, Roche, Swixx. Other support: travel support: AstraZeneca, Egis, Gilead, Novartis, Roche. Contracted research: Amgen, AstraZeneca, Eli Lilly, Gilead, Novartis, OBI Pharma, Roche, Samsung, Seagen. Medical writing: AstraZeneca, Eli Lilly. Royalties: Springer. Sandra M. Swain: Receipt of grants/research supports: Kailos Genetics, Genentech/Roche. Receipt of honoraria or consultation fees: Athenex, AstraZeneca, Biotheranostics, Natera, Exact Sciences, Lilly, Merck, Genentech/Roche, Sanofi, Daiichi Sankyo, Molecular Templates, Napo Pharmaceuticals. Stock shareholder: SEAGEN. Other support: CO- PI of INAVO 122 Genentech/Roche with in-kind travel to investigator meetings, Travel related expenses in kind Sanofi and Daiichi Sankyo. Peter Vuylsteke: Receipt of grants/research supports: UICC grant. Receipt of honoraria or consultation fees: Roche, Novartis and MSD. Theresa Wiseman: Receipt of grants/research supports: Receiver of SPCC Pfizer grant. Binghe Xu: Receipt of grants/research supports: sponsored research to my institution from Roche, AstraZeneca and Pfizer. Receipt of honoraria or consultation fees: advisory or consultancy fees from Novartis and Roche. Participation in a sponsored speakers' bureau: speakers’ bureau fees from AstraZeneca, Pfizer, Roche, Eisai. Elizabeth Bergsten-Nordström, Alberto Costa, Runcie C. W. Chidebe, Prudence A. Francis, Xichun Hu, Renate Haidinger, Leonor Matos, Shirley A. Mertz, Birgitte V. Offersen, Olivia Pagani, Eva Schumacher-Wulf, Daniel A. Vorobiof, Frédéric E. Lecouvet, and Eric P. Winer reported no significant relationships. William J. Gradishar, George W. Sledge and Christoph Thomssen have not submitted a disclosure of interests’ form., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Purpose: AMEERA-5 investigated amcenestrant (oral selective estrogen receptor [ER] degrader) plus palbociclib versus letrozole plus palbociclib as first-line treatment for ER-positive/human epidermal growth factor receptor 2-negative (ER+/HER2-) advanced/metastatic breast cancer (aBC)., Materials and Methods: In AMEERA-5 (ClinicalTrials.gov identifier: NCT04478266), a double-blind, double-dummy, international phase III trial, adult pre-/post-menopausal women and men without previous systemic therapy for ER+/HER2- aBC were randomly assigned 1:1 to amcenestrant 200 mg once daily + standard palbociclib dosage (125 mg once daily, 21 days on/7 days off) or letrozole 2.5 mg once daily + standard palbociclib dosage, stratified by de novo metastatic disease, postmenopausal women, and visceral metastasis. The primary end point was progression-free survival (PFS), compared using a stratified log-rank test with one-sided type I error rate of 2.5%. Secondary end points included overall survival (key secondary), pharmacokinetics, and safety., Results: Between October 14, 2020, and December 2, 2021, 1,068 patients were randomly assigned to amcenestrant + palbociclib (N = 534) or letrozole + palbociclib (N = 534). At the interim analysis (median follow-up 8.4 months), the stratified hazard ratio for PFS was 1.209 (95% CI, 0.939 to 1.557; one-sided P value = .9304); therefore, the study was stopped for futility. The 6-month PFS rate was 82.7% (95% CI, 79.0 to 85.8) with amcenestrant + palbociclib versus 86.9% (95% CI, 83.5 to 89.6) with letrozole + palbociclib. In the amcenestrant + palbociclib versus letrozole + palbociclib groups, treatment-emergent adverse events (any grade) occurred in 85.6% versus 85.4% of patients and grade ≥3 events in 46.3% versus 60.8%, respectively., Conclusion: The AMEERA-5 study was discontinued on the basis of the recommendation of the data monitoring committee at the interim futility analysis. No new safety signals were identified.

The proposed role of CDH1 (E-cadherin gene) methylation as a mechanism of gene inactivation in invasive lobular carcinoma (ILC) remains inconclusive. For many years, CDH1 promoter hypermethylation has been regarded as a mechanism for gene inactivation in ILC. However, this assumption has primarily relied on non-quantitative assays, which have reported CDH1 methylation frequencies ranging from 26 to 93% at CpG sites within the island region. Few studies employing quantitative methods and covering CpG island shores, regions of relatively low CpG density situated proximal to conventional promoter CpGs, have been conducted, revealing lower percentages of methylation ranging from 0 to 51%. Therefore, using the quantitative pyrosequencing method, we examined CDH1 methylation in the island region and shores in E-cadherin deficient ILC cases (15 with CDH1 mutation and 22 non-mutated), 19 cases of invasive breast carcinomas non-special type (IBC-NSTs), and five cases of usual ductal hyperplasia (UDH). Our analysis revealed CDH1 methylation frequencies ranging from 3 to 64%, with no significant increase in methylation levels in any group of ILCs (median = 12%) compared to IBC-NST (median = 15%). In addition, considering the poorly studied association between the number of tumor-infiltrating lymphocytes (TILs) and CDH1 methylation in breast cancer, we undertook a thorough analysis within our dataset. Our findings revealed a positive correlation between CDH1 methylation and the presence of TILs (r = 0.5; p-value < 0.05), shedding light on an aspect of breast cancer biology warranting further investigation. These findings challenge CDH1 methylation as a CDH1 inactivation mechanism in ILC and highlight TILs as a potential confounding factor in gene methylation., (© 2024. The Author(s).)

Background: The capsule formulation of CDK4/6 inhibitor palbociclib has reduced solubility at gastric pH > 4.5 and may have decreased activity when used with proton-pump inhibitors (PPI). Herein, we report the effect of PPI on palbociclib capsule activity and safety in the PARSIFAL study., Methods: First-line endocrine-sensitive, hormone receptor-positive (HR+)/human epidermal growth factor receptor 2-negative (HER2-) advanced breast cancer (ABC) patients received palbociclib capsules plus fulvestrant or letrozole. The primary endpoint was progression-free survival (PFS). This post-hoc analysis compared PPI use. Patients were PPI-naïve (N-PPI) if not on PPI during the study, and either early (E-PPI) or long-term PPI (LT-PPI) if on PPI at study entry or for at least ≥⅔ of treatment, respectively. PPI groups were not mutually exclusive., Results: Among 486 patients, 66.9 % were N-PPI, 13.2 % E-PPI, 18.7 % LT-PPI, and 11.5 % of the PPI users were defined as neither. Median PFS (mPFS) was 29.6 months in the study population, 28.7 months in N-PPI, 23.0 months in E-PPI (Hazard Ratio [HR] 1.5; 95%Confidence Interval [CI] 1.1-2.2; p = 0.024), and 23.0 months in LT-PPI (HR 1.4; 95%CI 1.0-1.9; p = 0.035). By landmark analysis, PPI use was associated with poorer mPFS at 3 and 12 months. Grade ≥3 hematological adverse events occurred in 71.7 % of N-PPI, 57.8 % of E-PPI (p = 0.021), and 54.9 % of LT-PPI (p = 0.003). Dose reductions and dosing delays due to hematological toxicity occurred in 70.8 % of N-PPI, 56.3 % of E-PPI (p = 0.018), and 52.7 % of LT-PPI (p = 0.002)., Conclusions: PPI use may reduce palbociclib capsule toxicity, dose modifications, and clinical activity in HR+/HER2- ABC., Competing Interests: Declaration of competing interest SDC reports consulting for MEDSIR and IQVIA and honoraria from Pierre-Fabre, Novartis, and AstraZeneca. JMPG reports consulting for Roche, Eiasi, Daichii Sankyo, AstraZeneca, Gilead, MSD and Seagen and travel expenses from Roche. MB reports consulting fees from Pfizer, Novartis, Lilly, and Steamline-Menarini; honoraria from Pfizer, Novartis, and Lilly; and trave support from Pfizer. FD reports travel grants for Daichii, Novartis, and Pfizer, and participation in monitor/advisory boards for Daiichi, Seagen, Novartis, Gilead, Lilly, and MSD. MGG reports honoraria from Pfizer, Novartis, and AstraZeneca, travel grants from Lilly, Daiichi-Sankyo, and Pfizer, and participation in monitoring/advisory boards for AstraZeneca, Seagen, and Gilead. MRB reports honoraria from Pfizer, Novartis, AstraZenca, and Daiichi Sankyo. JG reports consulting fees from Novartis, Pfizer, AstraZeneca; honoraria from Novartis; and travel support from Roche and AstraZeneca. EAO reports consulting for AstraZeneca, Daichii, Gilead, MSD, and Seagen; honoraria from AstraZeneca, Daichii, Lilly, MSD, and Seagen; travel support from Daichii, Lilly, Gilead, and AstraZeneca; and participation in monitor/advisory boards for Gilead, AstraZeneca, Seagen, and Dachii. PS reports honoraria from Pfizer, AstraZeneca, Novartis, Roche, Merck, and Boehringer Ingelheim; a consulting role for Pfizer, AstraZeneca, Novartis, Roche, Merck, Boehringer Ingelheim, Bayer, Eisai, Celgene, and Puma; and institutional grants from Roche, Genentech, Oncogenex, and Novartis. FM reports grants from Roche, Novartis, AstraZeneca, GSK, MSD, Clovis, Vaccibody, Gilead Sciences, and Esai; consulting fees from AstraZeneca, GSK, and Roche; honoraria from AstraZeneca, MSD, Lilly, Pfizer, Novartis, GSK, Clovis, Myriad, Daiich Sankyo, Seagen, Pierre-Fabre, and Agendia; travel support from AstraZeneca, GSK, Pfizer, and Roche; and participation in advisory boards for Palleos and Amgen. JG reports grant/research support from Roche, Eiasi, and Exact Science; honoraria or consultation fees from AstraZeneca, Daiichi, Eisai, Exact Science, Evapharm, GE Healthcare, Gilead, Lilly, MSD, Novartis, Pfizer, Pierre Fabre, Roche, Seagen, Sothema and participation in company sponsored speaker's bureaus for Exact Science, Lilly, and Novartis. AS reports grants from Celgene, Roche, Abbvie; travel grants from Celgene, Roche, Pfizer, AstraZeneca, and honoraria from Roche, Celgene, Pfizer, AstraZeneca, Novartis, MSD, Tesaro, Lilly, Seagen, Gilead, GSK, Bayer, Amgen, Pierre Fabre. JA reports trial funding from MEDSIR and consulting for Pfizer, Lilly, and Novartis. PZ reports honoraria from Pfizer, Novartis, Roche, and Pierre Fabre; and travel support from Pfizer, Novartis, Roche, and Lilly. DW reports honoraria from Pfizer, Novartis, AstraZeneca and travel grants from Roche, and Novartis. JC reports consulting for Roche, Celgene, Cellestia, AstraZeneca, Seattle Genetics, Daiichi Sankyo, Erytech, Athenex, Polyphor, Lilly, Merck Sharp&Dohme, GSK, Leuko, Bioasis, Clovis Oncology, Boehringer Ingelheim, Ellipses, Hibercell, BioInvent, Gemoab, Gilead, Menarini, Zymeworks, Reveal Genomics, Expres2ion Biotechnologies; honoraria from Roche, Novartis, Celgene, Eisai, Pfizer, Samsung Bioepis, Lilly, Merck Sharp&Dohme, Daiichi Sankyo.; research funding to the Institution from Roche, Ariad pharmaceuticals, AstraZeneca, Baxalta GMBH/Servier Affaires, Bayer healthcare, Eisai, F. Hoffman-La Roche, Guardanth health, Merck Sharp&Dohme, Pfizer, Piqur Therapeutics, Puma C, Queen Mary University of London; stock shares for MEDSIR, Nektar Pharmaceuticals, Leuko (relative); Travel, accommodation, expenses from Roche, Novartis, Eisai, Pfizer, Daiichi Sankyo, Astrazeneca, Gilead; and Patents: Pharmaceutical Combinations of A Pi3k Inhibitor And A Microtubule Destabilizing Agent. Javier Cortés Castán, Alejandro Piris Giménez, Violeta Serra Elizalde. WO 2014/199294 A. ISSUED Her2 as a predictor of response to dual HER2 blockade in the absence of cytotoxic therapy. Aleix Prat, Antonio Llombart, Javier Cortés. US 2019/0338368 A1. LICENSED. ALC reports research support from Roche, Agendia, Lilly, Pfizer, Novartis, Merck Sharp & Dohme, Gilead, and Daichii-Sanyo; consulting for Lilly, Roche, Pfizer, and Novartis; participation in speakers' bureaus for Lilly, AstraZeneca, Merck Sharp & Dohme; travel support from Roche, Pfizer, AstraZeneca; and stock or other ownership in MEDSIR and Initia-Research. The remaining authors declare no conflicts of interest., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Trastuzumab deruxtecan (T-DXd) demonstrated significantly improved efficacy over trastuzumab emtansine (T-DM1) in DESTINY-Breast03 (median follow-up, 28 months). We report updated efficacy and safety analyses, including secondary and exploratory efficacy endpoints (median follow-up, 41 months) of DESTINY-Breast03. Patients with advanced HER2-positive metastatic breast cancer previously treated with taxane and trastuzumab were randomized to T-DXd (5.4 mg per kg (261 patients)) or T-DM1 (3.6 mg per kg (263 patients)). The primary endpoint was progression-free survival (PFS) by blinded independent central review and was previously reported. The key secondary endpoint was overall survival (OS). Other secondary endpoints included objective response rate, duration of response and PFS (all by investigator assessment) and safety. At data cutoff, 20 November 2023, median PFS by investigator assessment was 29.0 versus 7.2 months (hazard ratio (HR), 0.30; 95% confidence interval (CI), 0.24-0.38), the 36-month PFS rate was 45.7% versus 12.4% and median OS was 52.6 versus 42.7 months (HR, 0.73; 95% CI, 0.56-0.94) with T-DXd versus T-DM1, respectively. Treatment-emergent adverse events were consistent with the previous analyses. No new instances of grade ≥3 interstitial lung disease or pneumonitis occurred (all grade rate, 16.7% (T-DXd) versus 3.4% (T-DM1)). With longer follow-up, T-DXd continued to demonstrate superior efficacy over T-DM1 with a manageable safety profile. ClinicalTrials.gov registration: NCT03529110 ., (© 2024. The Author(s).)

Background: The PHERGain study (NCT03161353) is assessing early metabolic responses to neoadjuvant treatment with trastuzumab-pertuzumab and chemotherapy de-escalation using a [ 18 Fluorine]fluorodeoxyglucose-positron emission tomography ([ 18 F]FDG-PET) and a pathological complete response-adapted strategy in HER2-positive (HER2+) early breast cancer (EBC). Herein, we present RESPONSE, a PHERGain substudy, where clinicopathological and molecular predictors of [ 18 F]FDG-PET disease detection were evaluated., Methods: A total of 500 patients with HER2 + EBC screened in the PHERGain trial with a tumor size > 1.5 cm by magnetic resonance imaging (MRI) were included in the RESPONSE substudy. PET[-] criteria entailed the absence of  ≥ 1 breast lesion with maximum standardized uptake value (SUVmax) ≥ 1.5 × SUVmean liver + 2 standard deviation. Among 75 PET[-] patients screened, 21 with SUVmax levels < 2.5 were randomly selected and matched with 21 PET[+] patients with SUVmax levels ≥ 2.5 based on patient characteristics associated with [ 18 F]FDG-PET status. The association between baseline SUVmax and [ 18 F]FDG-PET status ([-] or [+]) with clinicopathological characteristics was assessed. In addition, evaluation of stromal tumor-infiltrating lymphocytes (sTILs) and gene expression analysis using PAM50 and Vantage 3D™ Cancer Metabolism Panel were specifically compared in a matched cohort of excluded and enrolled patients based on the [ 18 F]FDG-PET eligibility criteria., Results: Median SUVmax at baseline was 7.2 (range, 1-39.3). Among all analyzed patients, a higher SUVmax was associated with a higher tumor stage, larger tumor size, lymph node involvement, hormone receptor-negative status, higher HER2 protein expression, increased Ki67 proliferation index, and higher histological grade (p < 0.05). [ 18 F]FDG-PET [-] criteria patients had smaller tumor size (p = 0.014) along with the absence of lymph node involvement and lower histological grade than [ 18 F]FDG-PET [+] patients (p < 0.01). Although no difference in the levels of sTILs was found among 42 matched [ 18 F]FDG-PET [-]/[+] criteria patients (p = 0.73), [ 18 F]FDG-PET [-] criteria patients showed a decreased risk of recurrence (ROR) and a lower proportion of PAM50 HER2-enriched subtype than [ 18 F]FDG-PET[+] patients (p < 0.05). Differences in the expression of genes involved in cancer metabolism were observed between [ 18 F]FDG-PET [-] and [ 18 F]FDG-PET[+] criteria patients., Conclusions: These results highlight the clinical, biological, and metabolic heterogeneity of HER2+ breast cancer, which may facilitate the selection of HER2+ EBC patients likely to benefit from [ 18 F]FDG-PET imaging as a tool to guide therapy., Trial Registration: Clinicaltrials.gov; NCT03161353; registration date: May 15, 2017., (© 2024. The Author(s).)

Purpose: The prognostic and predictive role of trophoblast cell-surface antigen-2 (Trop-2) overexpression in human epidermal growth factor receptor 2-positive (HER2-positive) breast cancer is currently unknown. We retrospectively analyzed Trop-2 expression and its correlation with clinicopathologic features and pathological complete response (pCR) in HER2-positive early breast cancer (EBC) patients treated with neoadjuvant docetaxel, carboplatin, trastuzumab, and pertuzumab in the PHERGain study., Methods: Trop-2 expression at baseline was determined in formalin-fixed, paraffin-embedded primary tumor biopsies by immunohistochemistry and was first classified into expressing (Trop-2-positive) or not-expressing (Trop-2-negative) tumors. Then, it was classified by histochemical score (H-score) according to its intensity into low (0-9), intermediate (10-49), and high (≥ 50). The association between clinicopathologic features, pCR, and Trop-2 expression was performed with Fisher's exact test., Results: Forty-one patients with tissue evaluable for Trop-2 expression were included, with 28 (68.3%) Trop-2-positive tumors. Overall, 17 (41.46%), 14 (34.15%), and 10 (24.40%) tumors were classified as low, intermediate, and high, respectively. Trop-2 expression was significantly associated with decreased pCR rates (50.0% vs. 92.3%; odds ratio [OR] 0.05; 95% CI, 0.002-0.360]; p adjusted = 0.01) but was not correlated with any clinicopathologic features (p ≥ 0.05). Tumors with the highest Trop-2 H-score were less likely to obtain a pCR (OR 0.03; 95% CI, 0.001-0.290, p adjusted < 0.01). This association was confirmed in univariate and multivariate regression analyses., Conclusion: These findings suggest a potential role of Trop-2 expression as a biomarker of resistance to neoadjuvant chemotherapy plus dual HER2 blockade and may become a strategic target for future combinations in HER2-positive EBC patients., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

The PHERGain trial investigated the potential of metabolic imaging to identify candidates for chemotherapy deescalation in human epidermal growth factor receptor 2 (HER2)-positive, invasive, operable breast cancer with at least 1 breast lesion evaluable by [ 18 F]FDG PET/CT. [ 18 F]FDG PET/CT responders were defined as patients with an SUV max reduction (ΔSUV max ) of at least 40% in all of their target lesions after 2 cycles of trastuzumab and pertuzumab (HP) (with or without endocrine therapy). In total, 227 of 285 patients (80%) included in the HP arm showed a predefined metabolic response and received a total of 8 cycles of HP (with or without endocrine therapy). Pathologic complete response (pCR), defined as ypT0/isN0, was achieved in 37.9% of the patients. Here, we describe the secondary preplanned analysis of the best cutoff of ΔSUV max for pCR prediction. Methods: Receiver-operating-characteristic analysis was applied to look for the most appropriate ΔSUV max cutoff in HER2-positive early breast cancer patients treated exclusively with neoadjuvant HP (with or without endocrine therapy). Results: The ΔSUV max capability of predicting pCR in terms of the area under the receiver-operating-characteristic curve was 72.1% (95% CI, 65.1-79.2%). The optimal ΔSUV max cutoff was found to be 77.0%, with a 51.2% sensitivity and a 78.7% specificity. With this cutoff, 74 of 285 patients (26%) would be classified as metabolic responders, increasing the pCR rate from 37.9% (cutoff ≥ 40%) to 59.5% (44/74 patients) ( P < 0.01). With this optimized cutoff, 44 of 285 patients (15.4%) would avoid chemotherapy in either the neoadjuvant or the adjuvant setting compared with 86 of 285 patients (30.2%) using the original cutoff ( P < 0.001). Conclusion: In the PHERGain trial, an increased SUV max cutoff (≥77%) after 2 cycles of exclusive HP (with or without endocrine therapy) achieves a pCR in the range of the control arm with chemotherapy plus HP (59.5% vs. 57.7%, respectively), further identifying a subgroup of patients with HER2-addicted tumors. However, the original cutoff (≥40%) maximizes the number of patients who could avoid chemotherapy., (© 2024 by the Society of Nuclear Medicine and Molecular Imaging.)

Background: DESTINY-Breast03 is a randomized, multicenter, open-label, phase III study of trastuzumab deruxtecan (T-DXd) versus trastuzumab emtansine (T-DM1) in patients with human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer (mBC) previously treated with trastuzumab and a taxane. A statistically significant improvement in progression-free survival (PFS) versus T-DM1 was reported in the primary analysis. Here, we report exploratory efficacy data in patients with and without brain metastases (BMs) at baseline., Patients and Methods: Patients were randomly assigned 1 : 1 to receive T-DXd 5.4 mg/kg or T-DM1 3.6 mg/kg. Patients with clinically inactive/asymptomatic BMs were eligible. Lesions were measured as per modified RECIST, version 1.1. Outcomes included PFS by blinded independent central review (BICR), objective response rate (ORR), and intracranial ORR as per BICR., Results: As of 21 May 2021, 43/261 patients randomized to T-DXd and 39/263 patients randomized to T-DM1 had BMs at baseline, as per investigator assessment. Among patients with baseline BMs, 20/43 in the T-DXd arm and 19/39 in the T-DM1 arm had not received prior local BM treatment. For patients with BMs, median PFS was 15.0 months [95% confidence interval (CI) 12.5-22.2 months] for T-DXd versus 3.0 months (95% CI 2.8-5.8 months) for T-DM1; hazard ratio (HR) 0.25 (95% CI 0.13-0.45). For patients without BMs, median PFS was not reached (95% CI 22.4 months-not estimable) for T-DXd versus 7.1 months (95% CI 5.6-9.7 months) for T-DM1; HR 0.30 (95% CI 0.22-0.40). Confirmed systemic ORR was 67.4% for T-DXd versus 20.5% for T-DM1 and 82.1% for T-DXd versus 36.6% for T-DM1 for patients with and without BMs, respectively. Intracranial ORR was 65.7% with T-DXd versus 34.3% with T-DM1., Conclusions: Patients with HER2-positive mBC whose disease progressed after trastuzumab and a taxane achieved a substantial benefit from treatment with T-DXd compared with T-DM1, including those with baseline BMs., Competing Interests: Disclosure SAH reports contracted paid research from Ambrx, Amgen, AstraZeneca, Arvinas, Bayer, CytomX, Daiichi Sankyo, Dignitana, Genentech/Roche, Gilead, GSK, Immunomedics, Eli Lilly, Macrogenics, Novartis, Pfizer, OBI Pharma, Orinove, Pieris, PUMA, Radius, Sanofi, Seagen, Zymeworks, and Phoenix Molecular Designs, Ltd; institutional grants from Ambrx and Samumed; research funding as national/international principal investigator from Novartis, Daiichi Sankyo, Seagen, and GNE/Roche; is a steering committee member of Novartis, Lilly, Daiichi Sankyo/AstraZeneca, GNE/Roche, and Sanofi; travel expenses paid for by Lilly (2019); and uncompensated consulting/advisory board memberships with 4DPharma, Ambrx, Amgen, Artios, Arvinas, Daiichi Sankyo, Dantari, Genentech/Roche, Immunomedics, Macrogenics, Eli Lilly, Novartis, NK Max, Pieris, Pyxis, Seagen, and Biotheranostics. SBK reports institutional research grants from Novartis, Sanofi Aventis, and Dongkook Pharmaceutical Company; consulting fees from Novartis, AstraZeneca, Lilly Dae Hwa Pharmaceutical Co, Ltd, IUS Abxis, and Daiichi Sankyo; participation on an advisory board with Lilly Dae Hwa Pharmaceutical Co, Ltd, IUS Abxis, Daiichi Sankyo, and Beigene; leadership or fiduciary role with ESMO Breast 2021-2023; and stocks or stock options from Genopeak and NeoGene TC. WPC reports payment or honoraria for lectures and presentations from Amgen, AstraZeneca, Chugai Pharma, Daiichi Sankyo, Eli Lilly, Everest Medicine, Foundation Medicine Kyowa Kirin, Novartis, Pfizer, Roche, Sanofi, and Takeda; travel support from Amgen, AstraZeneca, Pfizer, and Roche; participation on data safety monitoring or advisory board with Amgen, AstraZeneca, Daiichi Sankyo, Everest Medicine, Eli Lilly, IMPACT Therapeutics, MSD, Novartis, Pfizer, Roche, and Sanofi. SAI reports grants or contracts from AstraZeneca, Boryung Pharm, Daewoong Pharmaceutical Co. Ltd, Eisai, Pfizer, and Roche; and consulting fees from AstraZeneca, Hanmi, Idience, Lilly, MSD, GSK, Pfizer, Novartis, Roche, and Daiichi Sankyo. YHP reports grants or contracts from AstraZeneca, Roche, Pfizer, Gencurix, and Novartis; consulting fees from Pfizer, AstraZeneca, Roche, MSD, Eisai, Novartis, Daiichi Sankyo, and Lilly; payment or honoraria from Pfizer, Roche, MSD, and Novartis; participation on data safety monitoring or advisory board with Roche, AstraZeneca, Eisai, MSD, Daiichi Sankyo, and Novartis. VP reports payment or honoraria from Daiichi Sankyo, Novartis, Pfizer, and AstraZeneca; travel support from Pfizer, Mundipharma, Daiichi Sankyo, and Lilly; and participation on an advisory board with Daiichi Sankyo. CFC reports participation on a data safety monitoring or advisory board with Roche, Pfizer, and Daiichi Sankyo. HI reports consulting fees from Daichi Sankyo, Chugai, AstraZeneca, Sanofi, Lilly, MSD, Pfizer, and Novartis; and payment or honoraria from Daiichi Sankyo, Chugai, AstraZeneca, Lilly, MSD, and Pfizer. EH reports institutional research and consulting fees for the present manuscript from Daiichi Sankyo and AstraZeneca; other institutional research grants from AbbVie, Acerta Pharma, ADC Therapeutics, AKESOBIO Australia, Amgen, Aravive, ArQule, Arvinas AtlasMedX, Black Diamond, Boehringer Ingelheim, Clovis, Compugen, Curis, CytomX, Dana Farber Cancer Institute, Deciphera, eFFECTOR Therapeutics, Ellipses Pharma, EMD Serono, Fochon, FujiFilm, G1 Therapeutics, H3 Biomedicine, Harpoon, Hutchinson MediPharma, Immunogen, Immunomedics, Incyte, InvestisBio, Jacobio, Karyopharm, Leap Therapeutics, Lilly, Lycera, Mabspace Biosciences, Macrogenics, MedImmune, Merck, Mersana, Merus, Millenium, Molecular Templates, Myriad Genetic Labs, Novartis, Nucana, Olema, OncoMed, Onconova Therapeutics, ORIC Pharmaceuticals, Orinove, Pfizer, PharmaMar, Pieris Pharmaceuticals, Pionyr Immunotherapeutics, Plexxikon, Radius Health, Regeneron, Repertoire Immune Medicine, Rgenix, Roche/Genentech, Seagen, Sermonix Pharmaceuticals, Shattuck Labs, Silverback, StemCentRx, Sutro, Syndax, Syros, Taiho, TapImmune, Tesaro, Treadwell Therapeutics, Verastem, Vincerx Pharma, Zenith Epigenetics, and Zymeworks; and consulting fees from Arcus, Arvinas, Black Diamond, Boehringer Ingelheim, CytomX, Dantari, Deciphera Pharmaceuticals, Eisai, H3 Biomedicine, iTeos, Janssen, Lilly, Loxo, Merck, Mersana, Novartis, Pfizer, Puma Biotechnology, Relay Therapeutics, Roche/Genentech, Seagen, and Silverback Therapeutics. GC reports support for the current manuscript from AstraZeneca and Daichii Sankyo; grants or contracts from Merck; consulting fees from Bristol Myers Squibb, Roche, Pfizer, Novartis, Lilly, AstraZeneca, Daichii Sankyo, Merck, Seagen, and Ellipsis; payments or honoraria from Pfizer and Lilly; and travel support from Roche and Lilly. BX reports consulting fees from AstraZeneca and Novartis and payments or honoraria for lectures from AstraZeneca, Pfizer, and Roche. AE reports stocks/stock options from and is an employee of Daiichi Sankyo. YL reports stocks/stock options from and was an employee of Daiichi Sankyo at the time of the study. JC is an employee of Daiichi Sankyo. EB was an employee of Daiichi Sankyo at the time of the study. KT is an employee of Daiichi Sankyo. SV reports stocks/stock options from and is an employee of AstraZeneca. JC reports support for the current work from Daiichi Sankyo and AstraZeneca; consulting fees from AstraZeneca, Athenex, Bioasis, BioInvent, Boehringer Ingelheim, Celgene, Cellestia, Clovis Oncology, Daiichi Sankyo, Ellipses, Erytech, GEMoaB, Gilead, GSK, Hibercell, Leuko, Lilly, Menarini, Merck Sharp & Dohme, Polyphor, Roche, Seagen, Zymeworks; payment or honoraria from Celegene, Daiichi Sankyo, Eisai, Lilly, Merck Sharp & Dohme, Novartis, Pfizer, Roche, and Samsung Bioepis; travel support from AstraZeneca, Daiichi Sankyo, Eisai, Novartis, Pfizer, and Roche; stocks/stock options from Leuko (relative), MedSIR, and Nektar Pharmaceuticals. All other authors have declared no conflicts of interest., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: PHERGain was designed to assess the feasibility, safety, and efficacy of a chemotherapy-free treatment based on a dual human epidermal growth factor receptor 2 (HER2) blockade with trastuzumab and pertuzumab in patients with HER2-positive early breast cancer (EBC). It used an 18 fluorine-fluorodeoxyglucose-PET-based, pathological complete response (pCR)-adapted strategy., Methods: PHERGain was a randomised, open-label, phase 2 trial that took place in 45 hospitals in seven European countries. It randomly allocated patients in a 1:4 ratio with centrally confirmed, HER2-positive, stage I-IIIA invasive, operable breast cancer with at least one PET-evaluable lesion to either group A, where patients received docetaxel (75 mg/m 2 , intravenous), carboplatin (area under the curve 6 mg/mL per min, intravenous), trastuzumab (600 mg fixed dose, subcutaneous), and pertuzumab (840 mg loading dose followed by 420 mg maintenance doses, intravenous; TCHP), or group B, where patients received trastuzumab and pertuzumab with or without endocrine therapy, every 3 weeks. Random allocation was stratified by hormone receptor status. Centrally reviewed PET was conducted at baseline and after two treatment cycles. Patients in group B were treated according to on-treatment PET results. Patients in group B who were PET-responders continued with trastuzumab and pertuzumab with or without endocrine therapy for six cycles, while PET-non-responders were switched to receive six cycles of TCHP. After surgery, patients in group B who were PET-responders who did not achieve a pCR received six cycles of TCHP, and all patients completed up to 18 cycles of trastuzumab and pertuzumab. The primary endpoints were pCR in patients who were group B PET-responders after two treatment cycles (the results for which have been reported previously) and 3-year invasive disease-free survival (iDFS) in patients in group B. The study is registered with ClinicalTrials.gov (NCT03161353) and is ongoing., Findings: Between June 26, 2017, and April 24, 2019, a total of 356 patients were randomly allocated (71 patients in group A and 285 patients in group B), and 63 (89%) and 267 (94%) patients proceeded to surgery in groups A and B, respectively. At this second analysis (data cutoff: Nov 4, 2022), the median duration of follow-up was 43·3 months (range 0·0-63·0). In group B, the 3-year iDFS rate was 94·8% (95% CI 91·4-97·1; p=0·001), meeting the primary endpoint. No new safety signals were identified. Treatment-related adverse events and serious adverse events (SAEs) were numerically higher in patients allocated to group A than to group B (grade ≥3 62% vs 33%; SAEs 28% vs 14%). Group B PET-responders with pCR presented the lowest incidence of treatment-related grade 3 or higher adverse events (1%) without any SAEs., Interpretation: Among HER2-positive EBC patients, a PET-based, pCR-adapted strategy was associated with an excellent 3-year iDFS. This strategy identified about a third of patients who had HER2-positive EBC who could safely omit chemotherapy., Funding: F Hoffmann-La Roche., Competing Interests: Declaration of interests JMP-G reports consulting roles for Roche, Lilly, Eisai, Daiichi Sankyo, AstraZeneca, Gilead, MSD, and Seattle Genetics and travel expenses from Roche. JC reports consulting roles for Roche, Celgene, Cellestia, AstraZeneca, Biothera Phgroupaceutical, Merus, Seattle Genetics, Daiichi Sankyo, Erytech, Athenex, Polyphor, Lilly, Servier, MSD, GSK, Leuko, Bioasis, and Clovis Oncology; honoraria from Roche, Novartis, Celgene, Eisai, Pfizer, Samsung Bioepis, Lilly, MSD, and Daiichi Sankyo; research funding to their institution from Roche, Ariad pharmaceuticals, AstraZeneca, Baxalta GMBH/Servier Affaires, Bayer healthcare, Eisai, F Hoffman-La Roche, Guardanth health, MSD, Pfizer, Piqur Therapeutics, Puma C, and Queen Mary University of London; and intellectual property for Medica Scientia Innovation Research (MEDSIR). MR-B reports membership of a speaker bureau and advisory board for Novartis. MC reports a research grant to their institution from Roche and the role of co-chair of the scientific committee of the International Breast Cancer Study Group. AS reports consulting roles for Roche, AstraZeneca, Seagen, Novartis, and Boehringer Ingelheim; to be part of a speaker bureau for Daiichi Sankyo, Roche, and Novartis; and travel expenses from Pfizer, Novartis, and Eisai. BB reports receiving fees for medical education in a consulting or advisory role with MSD, Roche, Pierre Fabre, Novartis, AstraZeneca, and Seagen; participating in a speakers bureau for Pfizer, Roche, MSD, Palex, Eisai, Daichii Sankyo, AstraZeneca, and Seagen. SE-d-R reports consulting roles for Daiichi Sankyo/AstraZeneca, Seagen, and Pierre Fabre; to be part of a speaker bureau for Daiichi Sankyo/AstraZeneca, Pfizer, Novartis, Seagen; to have received research funding from Roche, Synthon, Byondis, MEDSIR, SOLTI, Zymeworks, and Daiichi Sankyo/AstraZeneca; and travel, accommodation, or expenses from Pfizer, Kern Pharma, and Daiichi Sankyo/AstraZeneca. NR reports research funding from Pfizer; and to be part of speaker bureau for Novartis, Pfizer, Gilead, and Daiichi Sankyo/AstraZeneca. FM reports grants from Roche, Novartis, AstraZeneca, GSK, MSD, Clovis, Vaccibody, Gilead Sciences, and Esai; consulting fees from AstraZeneca, GSK, and Roche; honoraria from AstraZeneca, MSD, Lilly, Pfizer, Novartis, GSK, Clovis, Myriad, Daiichi Sankyo, Seagen, Pierre Fabre, and Agendia; travel support from AstraZeneca, GSK, Pfizer, and Roche; and participation in advisory boards for Palleos and Amgen. AC reports consulting or advisory roles for Daiichi Sankyo/AstraZeneca, Seagen, and Pierre Fabre; being part of a speakers bureau for Daiichi Sankyo/AstraZeneca, Pfizer, Novartis, and Seagen; institutional research funding from Roche, Synthon, Byondis, MEDSIR, SOLTI, Zymeworks, and Daiichi Sankyo/AstraZeneca; and expert testimony and travel or accommodations expenses from Pfizer, Kern Pharma, and Daiichi Sankyo/AstraZeneca. AP reports honoraria from Pfizer, Novartis, Roche, MSD Oncology, Lilly, Daiichi Sankyo, and Amgen; to have consulting roles for Roche, AstraZeneca, Peptomyc, Novartis, and Daiichi Sankyo; research funding to their institution from Roche, AstraZeneca, Novartis, and Reveal Genomics; to have intellectual property (ERBB2 and HER2DX patents); travel expenses from Daiichi Sankyo; and a share in ownership at Reveal Genomics. PS reports honoraria from Pfizer, AstraZeneca, Novartis, Roche, Merck, and Boehringer Ingelheim; a consulting role in Pfizer, AstraZeneca, Novartis, Roche, Merck, Boehringer Ingelheim, Bayer, Eisai, Celgene, and Puma; and grants to their institution from Roche, Genentech, Oncogenex, and Novartis. SB reports a consulting or advisory board role at Daiichi Sankyo, AstraZeneca, Novartis, and Roche; speaker or conference fees from Daiichi Sankyo, AstraZeneca, Novartis, and Roche; and travel fees from Daiichi Sankyo, AstraZeneca, Novartis, and Roche. SDC reports receiving fees for medical education from Novartis, Pierre Fabre, and IQVIA; institutional grant IG 20774 of Fondazione AIRC per la Ricerca sul Cancro; Cancer Can.Heal European EU4 Health Programme 101080009–European Commission; and serving as an ad hoc medical advisor for MEDSIR. MG reports honoraria from Roche, Novartis, Gilead, and AstraZeneca; travel grants and accommodation from Roche, Pfizer, and AstraZeneca; and an advisory role at Gilead. GA reports honoraria from MEDSIR. AL-C reports leadership roles at Eisai, Celgene, Lilly, Pfizer, Roche, Novartis, and MSD; intellectual property for MEDSIR and Initia Research; to have consulting roles for Lilly, Roche, Pfizer, Novartis, Pierre Fabre, GenomicHealth, and GSK; to be part of a speakers bureau for Lilly, AstraZeneca, and MSD; research funding from Roche, Foundation Medicine, Pierre Fabre, and Agendia; and travel expenses from Roche, Lilly, Novartis, Pfizer, and AstraZeneca. CP, ES, DA-L, PG, JR-M, LM, and MS-C are employees of MEDSIR. All other authors declare no competing interests., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

What Is This Summary About?: Sacituzumab govitecan (brand name: TRODELVY ® ) is a new treatment for certain types of advanced or metastatic breast cancer. One common type of breast cancer has at least 1 of 2 hormone receptors (HR positive) and does not have human epidermal growth factor 2 (HER2 negative). The HR and HER2 receptors are known to influence how severe a case of breast cancer is. Certain treatments will only work if a specific receptor is present on breast cancer cells. HR-positive/HER2-negative advanced or metastatic breast cancer can be treated with sacituzumab govitecan. This is a summary of the results of the TROPiCS-02 study. This study compared sacituzumab govitecan with standard chemotherapy in participants with HR-positive/HER2-negative advanced or metastatic breast cancer., What Were the Results?: The study showed that participants treated with sacituzumab govitecan lived significantly longer without their cancer getting worse than participants treated with chemotherapy. Participants also survived significantly longer and their tumors became significantly smaller in more participants treated with sacituzumab govitecan than with chemotherapy. In general, participants treated with sacituzumab govitecan were more likely to have side effects and had more severe side effects. These side effects included low levels of a type of white blood cell known as neutrophils and diarrhea. Oncologists (doctors that treat cancer) know of these side effects as they are common among people being treated for cancer. Doctors can control these side effects by following standard treatment guidelines and the package insert for sacituzumab govitecan. Participants treated with sacituzumab govitecan maintained their sense of well-being and ability to do daily activities (quality of life) longer than participants treated with chemotherapy. It also took longer for fatigue and other symptoms of cancer to worsen in participants treated with sacituzumab govitecan compared with chemotherapy., What Do the Results Mean?: Sacituzumab govitecan is more effective than standard chemotherapies for people who have already received multiple treatments for HR-positive/ HER2-negative advanced breast cancer. The side effects from sacituzumab govitecan could generally be managed well by doctors. Although there were more side effects with sacituzumab govitecan than with chemotherapy, they were generally mild to moderate.

Introduction: Given the constant increase in the healthcare demand for examinations related to radio-guided surgery (RGS), our hospital adopted new professional profiles in the RGS team, in order to partially reduce the time spent by nuclear medicine physicians on this task., Aim: To analyze the process of incorporating the profiles of Diagnostic Imaging Technician (DIT) and Sentinel Node Referent Nurse (SNRN), evaluating their deployment in the procedures linked to the technique., Material and Methods: Analysis of RGS activity during the period 2018-2022, focusing on pre-surgical and surgical procedures related to breast cancer (BC) and malignant melanoma (MM), as they are those pathologies on which the transfer of care competencies was concentrated. Chronological evolution of the competencies assumed by the different profiles during their integration into the RGS team., Results: RGS's healthcare activity during the analyzed period experienced an increase of 109%. BC and MM were the pathologies that accounted for by far the greatest demand for care. The transfer of competencies in these two pathologies occurred in a progressive and staggered manner, with 74% (460/622) of the administration phase being carried out by the SNRN and 64% (333/519) of the surgeries by the DIT in 2022., Conclusions: The creation of a multidisciplinary RGS team that includes different professional profiles (nuclear medicine physician [MN], ERGC and TSID) is an effective strategy to respond to the increase in the complexity and number of all procedures related to RGS., (Copyright © 2023 Sociedad Española de Medicina Nuclear e Imagen Molecular. Published by Elsevier España, S.L.U. All rights reserved.)

Background: The HER2DX risk-score has undergone rigorous validation in prior investigations involving patients with early-stage human epidermal growth factor receptor 2 (HER2)-positive (HER2+) breast cancer. In this study, we present the outcomes of the HER2DX risk-score within the most recent release of the Sweden Cancerome Analysis Network-Breast (SCAN-B) HER2+ cohort. This updated examination benefits from a larger patient sample, an extended follow-up duration, and detailed treatment information., Materials and Methods: Clinical and RNAseq data from the SCAN-B dataset were retrieved from Gene Expression Omnibus (GSE81538). Among the 6600 patients, 819 had HER2+ breast cancer, with 757 individuals with research-based HER2DX risk-scores and corresponding survival outcomes. The HER2DX risk-score was evaluated (i) as a continuous variable and (ii) using predefined cut-offs. The primary endpoint for this study was overall survival (OS). The Kaplan-Meier method and Cox models were used to estimate OS and a multistate model with four states was fitted to better characterize patients' follow-up., Results: The median follow-up time was 7.5 years (n = 757). The most common systemic therapy was chemotherapy with trastuzumab (82.0%) and most tumors were classified as T1-T2 (97.1%). The HER2DX risk-score as a continuous variable was significantly associated with OS after adjustment for clinical variables and treatment regimen [hazard ratios (HR) per 10-unit increment = 1.31, 95% confidence interval (CI) 1.13-1.51, P < 0.001] as well as within predefined risk groups (high versus low; HR = 2.57, 95% CI 1.36-4.85, P < 0.001). Patients classified as HER2DX high-risk also had higher risk of (i) breast cancer recurrence and (ii) death without previous recurrence. Within the subgroup of HER2+ T1N0 tumors (n = 297), those classified as high-risk demonstrated inferior OS compared to low-risk tumors (7-year OS 77.8% versus 96.8%, P < 0.001). The HER2DX mRNA ERBB2 score was associated with clinical HER2 status (area under the receiver operating characteristic curve = 0.91)., Conclusions: In patients with early-stage HER2+ breast cancer, HER2DX risk-score provides prognostic information beyond clinicopathological variables, including treatment regimen with or without trastuzumab., Competing Interests: Role of the funder In addition to financial support, the funders actively contributed to various aspects of the research, including study design, data collection, analysis, interpretation, and report writing. Disclosure GV has received a speaker’s fee from MSD, Pfizer, GSK, and Pierre Fabre; has held an advisory role with AstraZeneca; and received consultant fees from Reveal Genomics. TP has received honoraria for speaker activities from AstraZeneca, Pfizer, Novartis, Veracyte, and Argenetics, and has held an advisory role with Novartis. FBM has a patent application (EP21383165). LP is listed as an inventor on patent PCT/EP2021/070788. OMS has declared travel expenses and consulting fees from Roche and Reveal, and speaker fees from Eisai, Daiichi-Sankyo, and Novartis. JC has ownership interests in MedSIR, Nektar, and Leuko; has held consulting or advisory roles in Celgene, Cellestia Biotech, AstraZeneca, Roche, Seattle Genetics, Daiichi-Sankyo, ERYTECH Pharma, Polyphor, Athenex, Lilly, Servier, Merck Sharp & Dohme, GlaxoSmithKline, Leuko, Clovis Oncology, Bioasis, Boehringer Ingelheim, Ellipses Pharma, HiberCell, Bioinvent, GEMoaB, Gilead Sciences, Menarini, Zymeworks, and Reveal Genomics; has received research funding from ARIAD, AstraZeneca, Baxalta, Bayer, Eisai, Guardant Health, Merck Sharp & Dohme, Pfizer, Puma Biotechnology, Queen Mary University of London, Roche, and Piqur; has patents, royalties, or other intellectual property from pharmaceutical combinations of a Pi3k Inhibitor and a microtubule destabilizing agent (Javier Cortés Castán, Alejandro Piris Giménez, Violeta Serra Elizalde. WO 2014/199294 A, Her2 as a predictor of response to dual HER2 blockade in the absence of cytotoxic therapy. Aleix Prat, Antonio Llombart, Javier Cortés. US 2019/ 0338368 A1); and has received travel expenses from Roche, Pfizer, Eisai, Novartis, Daiichi-Sankyo, and Gilead Sciences. EC has received honoraria for advisory roles from Pfizer, AstraZeneca, Daiichi-Sankyo, Roche, Novartis, Lilly, and MSD; and has received a speaker’s fee from Roche and Lilly. MM reports research grants from Puma; consulting/advisory fees from Roche, Novartis, AstraZeneca, Daiichi-Sankyo, Seagen, Lilly, and Sanofi; speakers’ honoraria from Seagen, Lilly, AstraZeneca, Pfizer, Daiichi-Sankyo, and Roche; a leadership or fiduciary role as Chairman, GEICAM and as a member of the Board of Directors for TRIO. PC reports speakers’ bureaus with AstraZeneca, GlaxoSmithKline, Novartis, and Roche; travel, accommodation, and expenses from Celgene, GlaxoSmithKline, and Novartis; and research funding from Merck Serono, Novartis, and Roche. LAC reports participation on a Data Safety Monitoring Board or Advisory Board of Sanofi Aventis, Novartis, Genentech/Roche, GSK, AstraZeneca/Daiichi-Sankyo, and Aptitude Health; and has a spouse serving on the board of Falcon Therapeutics and spouse involvement in a neural stem cell therapy patent. NH received consulting fees from Pierre Fabre and Roche. AV has the DNADX patent filed (EP22382387.3). GC served as consultant or advisor for Roche, Lilly, and Bristol-Myers Squibb; served on the speaker’s bureau for Roche, Pfizer, and Lilly; received travel funding from Pfizer and Roche; and received honoraria from Roche, Pfizer, Lilly, Novartis, and Seagen, all outside the submitted work. PV is one of the stockholders of Reveal Genomics, and also reports personal fees from NanoString. JSP is an equity stockholder and consultant for Reveal Genomics and is listed as an inventor on patent applications for the Breast PAM50 assay. CMP is an equity stockholder and consultant of BioClassifier LLC and Reveal Genomics, and is listed as an inventor on patent applications for the Breast PAM50 assay. AP reports advisory and consulting fees from Roche, Pfizer, Novartis, Amgen, Bristol-Myers Squibb, Puma, Oncolytics Biotech, MSD, Guardant Health, Peptomyc, and Lilly; lecture fees from Roche, Pfizer, Novartis, Amgen, Bristol-Myers Squibb, NanoString Technologies, and Daiichi-Sankyo; institutional financial interests from Boehringer, Novartis, Roche, NanoString, Sysmex Europa GmbH, Medica Scientia Innovation Research, SL, Celgene, Astellas, and Pfizer; is a stockholder and consultant of Reveal Genomics and SL; and is listed as an inventor on patent applications for the HER2DX assay. SMT reports consulting or advisory roles for Novartis, Pfizer, Merck, Eli Lilly, AstraZeneca, Genentech/Roche, Eisai, Sanofi, Bristol-Myers Squibb, Seattle Genetics, CytomX Therapeutics, Daiichi-Sankyo, Gilead, OncXerna, Zymeworks, Zentalis, Blueprint Medicines, Reveal Genomics, ARC Therapeutics, Infinity Therapeutics, Sumitovant Biopharma, Zetagen, Umoja Biopharma, Artios Pharma, Menarini/Stemline, Aadi Biopharma, Bayer, Incyte Corp, Jazz Pharmaceuticals, Natera, Tango Therapeutics, Systimmune, eFFECTOR, and Hengrui USA; research funding from Genentech/Roche, Merck, Exelixis, Pfizer, Lilly, Novartis, Bristol-Myers Squibb, Eisai, AstraZeneca, Gilead, NanoString Technologies, Seattle Genetics, and OncoPep; and travel support from Eli Lilly, Sanofi, Gilead, and Pfizer. All other authors have declared no conflicts of interest., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: The incorporation of circulating tumor DNA (ctDNA) into the management of operable breast cancer (BC) has been hampered by the heterogeneous results from different studies. We aimed to assess the prognostic value of ctDNA in patients with operable (non metastatic) BC., Materials and Methods: A systematic search of databases (PubMed/Medline, Embase, and CENTRAL) and conference proceedings was conducted to identify studies reporting the association of ctDNA detection with disease-free survival (DFS) and overall survival (OS) in patients with stage I-III BC. Log-hazard ratios (HRs) were pooled at each timepoint of ctDNA assessment (baseline, after neoadjuvant therapy, and follow-up). ctDNA assays were classified as primary tumor-informed and non tumor-informed., Results: Of the 3174 records identified, 57 studies including 5779 patients were eligible. In univariate analyses, ctDNA detection was associated with worse DFS at baseline [HR 2.98, 95% confidence interval (CI) 1.92-4.63], after neoadjuvant therapy (HR 7.69, 95% CI 4.83-12.24), and during follow-up (HR 14.04, 95% CI 7.55-26.11). Similarly, ctDNA detection at all timepoints was associated with worse OS (at baseline: HR 2.76, 95% CI 1.60-4.77; after neoadjuvant therapy: HR 2.72, 95% CI 1.44-5.14; and during follow-up: HR 9.19, 95% CI 3.26-25.90). Similar DFS and OS results were observed in multivariate analyses. Pooled HRs were numerically higher when ctDNA was detected at the end of neoadjuvant therapy or during follow-up and for primary tumor-informed assays. ctDNA detection sensitivity and specificity for BC recurrence ranged from 0.31 to 1.0 and 0.7 to 1.0, respectively. The mean lead time from ctDNA detection to overt recurrence was 10.81 months (range 0-58.9 months)., Conclusions: ctDNA detection was associated with worse DFS and OS in patients with operable BC, particularly when detected after treatment and using primary tumor-informed assays. ctDNA detection has a high specificity for anticipating BC relapse., Competing Interests: Disclosure GNM reports meeting/travel grants from AstraZeneca. EA reports consultancy fees/honoraria from Eli Lilly, Sandoz, and AstraZeneca; research grant to the institution from Gilead; meeting/travel grants from Novartis, Roche, Eli Lilly, Genetic, Istituto Gentili, Daiichi Sankyo, and AstraZeneca (all outside the submitted work). DMB reports full time employment at European Society for Medical Oncology since September 1, 2023; speaker’s engagement from Daiichi Sankyo/AstraZeneca; participation as medical research fellow in research studies with institutionally funded by Eli Lilly, Novartis, and F. Hoffmann-La Roche Ltd to Institut Jules Bordet; non-financial interest as member of the board of directors for Associaҫão de Investigaҫão e Ciudados de Suporte em Oncologia; non-remunerated prior leadership role as Portuguese Young Oncologists Committee Chair from Sociedade Portuguesa de Oncologia (all outside the submitted work). ALC reports leadership role at Eisai, Celgene, Lilly, Pfizer, Roche, Novartis, and MSD; intellectual property for MEDSIR; a consulting role for Lilly, Roche, Pfizer, Novartis, Pierre-Fabre, Exact Sciences, Seagen, and GSK; to be part of the speaker bureau for Lilly, AstraZeneca, and MSD; to receive research funding from Pfizer, Roche, Foundation Medicine, Exact Sciences, Pierre-Fabre, and Agendia; and travel compensation from Roche, Lilly, Novartis, Pfizer, and AstraZeneca. JC reports consulting/advisor role for Roche, Celgene, Cellestia, AstraZeneca, Seattle Genetics, Daiichi Sankyo, Erytech, Athenex, Polyphor, Lilly, Merck Sharp & Dohme, GSK, Leuko, Bioasis, Clovis Oncology, Boehringer Ingelheim, Ellipses, HiberCell, BioInvent, GEMoaB, Gilead, Menarini, Zymeworks, Reveal Genomics, Expres2ion Biotechnologies, Jazz Pharmaceuticals, and AbbVie; honoraria from Roche, Novartis, Celgene, Eisai, Pfizer, Samsung Bioepis, Lilly, Merck Sharp & Dohme, Daiichi Sankyo, AstraZeneca; research funding to the institution from Roche, Ariad pharmaceuticals, AstraZeneca, Baxalta GMBH/Servier Affaires, Bayer healthcare, Eisai, F. Hoffmann-La Roche, Guardant Health, Merck Sharp & Dohme, Pfizer, PIQUR Therapeutics, IQVIA, and Queen Mary University of London; stocks from MAJ3 Capital and Leuko (relative); travel, accommodation, and other expenses covered by Roche, Novartis, Eisai, Pfizer, Daiichi Sankyo, AstraZeneca, Gilead, and Merck Sharp & Dohme; patents ‘Pharmaceutical Combinations of A Pi3k Inhibitor And A Microtubule Destabilizing Agent’—Javier Cortés Castán, Alejandro Piris Giménez, Violeta Serra Elizalde, WO 2014/199294 A (issued) and ‘Her2 as a predictor of response to dual HER2 blockade in the absence of cytotoxic therapy’—Aleix Prat, Antonio Llombart, Javier Cortés, US 2019/ 0338368 A1 (licensed). MI reports honoraria from Novartis and Seattle Genetics; research support to the institution from Natera Inc, Inivata, Roche, and Pfizer; and travel grants from Roche and Gilead. GP reports being part of the advisory board/speaker bureau for Roche, Bayer, AstraZeneca, Novartis, Illumina, and ADS Biotech; and grants from Candriam and Thermo Fisher. EA reports honoraria and/or being part of the advisory board for Roche/GNE, Novartis, Seagen, Zodiac, Libbs, Pierre Fabre, Lilly, and Astra-Zeneca; travel grants from Roche/GNE and AstraZeneca; research grant to the institution from Roche/GNE, Astra-Zeneca, and GSK/Novartis. SDC reports being on the speaker’s bureau for AstraZeneca; and on the advisory board for Pierre-Fabre, IQVIA, and MEDSIR. All other authors have declared no conflicts of interest., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Background: Triple-negative breast cancer (TNBC) is an aggressive subtype that exhibits a high incidence of distant metastases and lacks targeted therapeutic options. Here we explored how the epigenome contributes to matrix metalloprotease (MMP) dysregulation impacting tumor invasion, which is the first step of the metastatic process., Methods: We combined RNA expression and chromatin interaction data to identify insulator elements potentially associated with MMP gene expression and invasion. We employed CRISPR/Cas9 to disrupt the CCCTC-Binding Factor (CTCF) binding site on an insulator element downstream of the MMP8 gene (IE8) in two TNBC cellular models. We characterized these models by combining Hi-C, ATAC-seq, and RNA-seq with functional experiments to determine invasive ability. The potential of our findings to predict the progression of ductal carcinoma in situ (DCIS), was tested in data from clinical specimens., Results: We explored the clinical relevance of an insulator element located within the Chr11q22.2 locus, downstream of the MMP8 gene (IE8). This regulatory element resulted in a topologically associating domain (TAD) boundary that isolated nine MMP genes into two anti-correlated expression clusters. This expression pattern was associated with worse relapse-free (HR = 1.57 [1.06 - 2.33]; p = 0.023) and overall (HR = 2.65 [1.31 - 5.37], p = 0.005) survival of TNBC patients. After CRISPR/Cas9-mediated disruption of IE8, cancer cells showed a switch in the MMP expression signature, specifically downregulating the pro-invasive MMP1 gene and upregulating the antitumorigenic MMP8 gene, resulting in reduced invasive ability and collagen degradation. We observed that the MMP expression pattern predicts DCIS that eventually progresses into invasive ductal carcinomas (AUC = 0.77, p < 0.01)., Conclusion: Our study demonstrates how the activation of an IE near the MMP8 gene determines the regional transcriptional regulation of MMP genes with opposing functional activity, ultimately influencing the invasive properties of aggressive forms of breast cancer., (© 2023. The Author(s).)

Despite recent treatment advances, the prognosis for patients with locally recurrent inoperable or metastatic triple-negative breast cancer (TNBC) remains poor. The antibody-drug conjugate datopotamab deruxtecan (Dato-DXd) is composed of a humanized anti-TROP2 IgG1 monoclonal antibody linked to a topoisomerase I inhibitor payload via a stable, cleavable linker. The phase III TROPION-Breast02 trial in patients previously untreated for locally recurrent inoperable or metastatic TNBC, who are not candidates for PD-1/PD-L1 inhibitors is evaluating efficacy and safety of Dato-DXd versus investigator's choice of chemotherapy (ICC). Approximately 600 patients will be randomized 1:1 to Dato-DXd 6 mg/kg iv. every 3 weeks or ICC (paclitaxel, nab-paclitaxel, carboplatin, capecitabine or eribulin mesylate). Dual primary end points are progression-free survival by blinded independent central review and overall survival.

Background: Sacituzumab govitecan demonstrated significant progression-free survival benefit over chemotherapy in the phase 3 TROPiCS-02 trial in patients with pretreated, endocrine-resistant hormone receptor-positive, human epidermal growth factor receptor 2-negative (HR+ and HER2-) metastatic breast cancer with limited treatment options. Here, we report the protocol-specified final analysis of overall survival and endpoints by trophoblast cell-surface antigen 2 (Trop-2) expression and other variables., Methods: In this randomised, open-label, multicentre, phase 3 trial, which took place in 91 centres across North America (the USA and Canada) and Europe (Belgium, France, Germany, Italy, the Netherlands, Spain, and the UK), patients were randomly assigned (1:1) to receive sacituzumab govitecan or chemotherapy (eribulin, vinorelbine, capecitabine, or gemcitabine). Patients had confirmed HR+ and HER2- locally recurrent inoperable or metastatic breast cancer and had received at least one previous endocrine therapy, a taxane, and a CDK4/6 inhibitor in any setting and two to four previous chemotherapy regimens for metastatic disease. The primary endpoint was progression-free survival (previously reported and not included in this analysis), and secondary endpoints included overall survival, objective response rate (ORR), and patient-reported outcomes. Overall survival was assessed using stratified log-rank tests and Cox regression. Trop-2 expression was assessed in tumour tissue by immunohistochemistry. In the statistical testing hierarchy, ORR and patient-reported outcomes were tested sequentially if overall survival was significant. This study is registered with ClinicalTrials.gov, NCT03901339., Findings: At the data cutoff date of July 1, 2022, 543 of 776 screened patients were randomly assigned between May 30, 2019, and April 5, 2021, with 272 patients in the sacituzumab govitecan group and 271 patients in the chemotherapy group. With a 12·5-month (IQR 6·4-18·8) median follow-up, 390 deaths occurred among 543 patients. Overall survival was significantly improved with sacituzumab govitecan versus chemotherapy (median 14·4 months [95% CI 13·0-15·7] vs 11·2 months [10·1-12·7]; hazard ratio [HR] 0·79, 95% CI 0·65-0·96; p=0·020); survival benefit was consistent across Trop-2 expression-level subgroups. ORR was significantly improved with sacituzumab govitecan compared with chemotherapy (57 [21%] patients vs 38 [14%]; odds ratio 1·63 [95% CI 1·03-2·56]; p=0·035), as was time to deterioration of global health status and quality of life (median 4·3 months vs 3·0 months; HR 0·75 [0·61-0·92]; p=0·0059) and fatigue (median 2·2 months vs 1·4 months; HR 0·73 [0·60-0·89]; p=0·0021). The safety profile of sacituzumab govitecan was consistent with previous studies (including the TROPiCS-02 primary analysis and the ASCENT trial). One fatal adverse event (septic shock caused by neutropenic colitis) was determined to be related to sacituzumab govitecan treatment., Interpretation: Sacituzumab govitecan demonstrated statistically significant and clinically meaningful benefit over chemotherapy, with a 3·2-month median overall survival improvement and a manageable safety profile. These data support sacituzumab govitecan as a new treatment option for patients with pretreated, endocrine-resistant HR+ and HER2- metastatic breast cancer., Funding: Gilead Sciences., Competing Interests: Declaration of interests HSR reports honoraria from Puma Biotechnology, Mylan, and Samsung Bioepis, and institutional research funding from Macrogenics, OBI Pharma, Pfizer, Novartis, Lilly, Genentech, Merck, Odonate Therapeutics, Daiichi Sankyo, Seattle Genetics, Sermonix Pharmaceuticals, AstraZeneca, Gilead Sciences, and Ayala Pharmaceuticals. AB reports institutional research funding from Genentech, Novartis, Pfizer, Merck, Sanofi, Radius Health and Menarini, Immunomedics and Gilead Sciences, Daiichi Sankyo, and AstraZeneca, and Eli Lilly, and consulting fees from Pfizer, Novartis, Genentech, Merck, Radius Health and Menarini, Immunomedics and Gilead Sciences, Sanofi, Daiichi Sankyo, AstraZeneca, Phillips, Eli Lilly, and Foundation Medicine. FM reports institutional research funding from Roche, Novartis, AstraZeneca, GSK and Tesaro, MED, Clovis, Vaccibody, Gilead Sciences, and Eisai; consulting fees from AstraZeneca, GSK and Tesaro, Pfizer, Eisai, Gilead Sciences, Vaccibody, and GenomicHealth; honoraria from AstraZeneca, Clovis, GSK and Tesaro, Eli Lilly, Novartis, Pfizer, Roche, Myriad Genetics, PharmaMar, Eisai, MSD, Immunomedics and Gilead Sciences, Pierre-Fabre, Agendia, Genomic Health, and Seattle Genetics; support for meeting attendance and travel from Pfizer, Roche, and AstraZeneca; and participation on a data safety monitoring board or advisory board for Palleos and Amgen. JC reports institutional research funding from Roche, Ariad Pharmaceuticals, AstraZeneca, Baxalta, Servier Affaires, Bayer Healthcare, Eisai, F Hoffman-La Roche, Guardant Health, Merck Sharp & Dohme, Pfizer, Piqur Therapeutics, Puma Biotechnology, and Queen Mary University of London; consulting fees from Roche, Celgene, Cellestia, AstraZeneca, Seattle Genetics, Daiichi Sankyo, Erytech, Athenex, Polyphor, Lilly, Merck, Sharp & Dohme, GSK, Leuko, Bioasis, Clovis Oncology, Boehringer Ingelheim, Ellipses, Hibercell, BioInvent, GEMoaB, Gilead Sciences, Menarini, Zymeworks, Reveal Genomics, and Expres2ion Biotechnologies; honoraria from Roche, Novartis, Celgene, Eisai, Pfizer, Samsung Bioepis, Lilly, Merck, Sharp & Dohme, and Daiichi Sankyo; travel and accommodations from Roche, Novartis, Eisai, Pfizer, Daiichi Sankyo, AstraZeneca, and Gilead Sciences; stock ownership from MedSIR and Nektar Pharmaceuticals; and several patents. PS reports institutional research funding from Astellas, AstraZeneca, Genentech, Novartis, Oncogenex, Roche, and Medivation; consulting fees from AstraZeneca, Bayer, Boehringer Ingelheim, Merck, Novartis, Pfizer, Puma, Roche, Eisai, and Celgene; and spouse's employment at Roche. DL reports honoraria from AstraZeneca, Novartis, MSD, Lilly, Amgen, Eisai, and Gilead Sciences; consulting fees from Roche, AstraZeneca, Pfizer, Novartis, MSD, Immunomedics, Pharma4D, Daiichi Sankyo, Lilly, Amgen, and Eisai; and travel and accommodations from Roche, AstraZeneca, Pfizer, Novartis, MSD, Gilead Sciences, and Amgen. OT reports institutional research funding from Bristol Myers Squibb and MSD; honoraria from Roche, Pfizer, Novartis-Sandoz, Lilly, MSD, AstraZeneca, Pierre Fabre, Seagen, Daiichi Sankyo, Gilead Sciences, Eisai, and Stemline; travel and accommodations from Roche, Pfizer, Novartis-Sandoz, Lilly, MSD, AstraZeneca, Seagen, Daiichi Sankyo, and Gilead Sciences; and participation on a data safety monitoring board or advisory board for Roche, Pfizer, Novartis-Sandoz, Lilly, MSD, AstraZeneca, Seagen, and Daiichi Sankyo. EC reports consulting fees from Novartis, Lilly, Pfizer, Roche, AstraZeneca, and Daiichi Sankyo; speaker's bureau from Lilly, Pfizer, AstraZeneca, and Daiichi Sankyo; and travel and accommodations from Pfizer and Roche. KLJ reports consulting fees from Novartis, Pfizer, Bristol Myers Squibb, Jounce Therapeutics, Taiho Oncology, Genentech, Synthon, AbbVie, Eisai, AstraZeneca, Blueprint Medicine, Daiichi Sankyo, Sun Pharma Advanced Research Company, Gilead Sciences, Seattle Genetics, and Lilly Pharmaceuticals and Loxo Oncology; and institutional research funding from Novartis, Clovis Oncology, Genentech, AstraZeneca, ADC Therapeutics, Novita Pharmaceuticals, Debio Pharmaceuticals, Pfizer, Lilly Pharmaceuticals and Loxo Oncology, Zymeworks, Immunomedics and Gilead Sciences, Puma Biotechnology, and Merck Pharmaceuticals. RD, TV, HW, MM, and OKY report employment by and stock ownership in Gilead Sciences. WV reports previous employment by and stock ownership in Genentech and employment by Gilead Sciences. SMT reports institutional research funding from Gilead Sciences, AstraZeneca, Eli Lilly, Merck, Nektar, Novartis, Pfizer, Genentech and Roche, Exelixis, Bristol Myers Squibb, Eisai, Nanostring, Cyclacel, Sanofi, Odonate, and Seagen; consulting fees from AstraZeneca, Eli Lilly, Merck, Nektar, Novartis, Pfizer, Genentech and Roche, Gilead Sciences, Bristol Myers Squibb, Eisai, Nanostring, Sanofi, Odonate, Seagen, Daiichi Sankyo, Athenex, CytomX, Blueprint Medicines, Zentalis, Zymeworks, Ellipses Pharma, 4D Pharma, OncoSec, Infinity Therapeutics, BeyondSpring Pharma, OncXerna, Reveal Genomics, ARC Therapeutics, Kyowa Kirin Pharma, G1 Therapeutics, Silverback Therapeutics, Certara, Mersana Therapeutics, and OncoPep; and honoraria from Chugai, Genentech and Roche, Eisai, Gilead Sciences, AstraZeneca, and Bristol Myers Squibb. All other authors declare no competing interests., (Copyright © 2023 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY-NC-ND 4.0 license. Published by Elsevier Ltd.. All rights reserved.)

Taselisib is a potent β-sparing phosphatidylinositol 3-kinase (PI3K) inhibitor that, with endocrine therapy, improves outcomes in phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA)-mutated (PIK3CAmut) advanced breast cancer. To understand alterations associated with response to PI3K inhibition, we analysed circulating tumour DNA (ctDNA) from participants enrolled in the SANDPIPER trial. Participants were designated as either PIK3CAmut or PIK3CA no mutation was detected (NMD) per baseline ctDNA. The top mutated genes and tumour fraction estimates identified were analysed for their association with outcomes. In participants with PIK3CAmut ctDNA treated with taselisib + fulvestrant, tumour protein p53 (TP53; encoding p53) and fibroblast growth factor receptor 1 (FGFR1) alterations were associated with shorter progression-free survival (PFS) compared to participants with NMD in these genes. Conversely, participants with PIK3CAmut ctDNA harbouring a neurofibromin 1 (NF1) alteration or high baseline tumour fraction estimate experienced improved PFS upon treatment with taselisib + fulvestrant compared to placebo + fulvestrant. Broadly, alterations in oestrogen receptor (ER), PI3K and p53 pathway genes were associated with resistance to taselisib + fulvestrant in participants with PIK3CAmut ctDNA. Altogether, we demonstrated the impact of genomic (co-)alterations on outcomes with one of the largest clinico-genomic datasets of ER+, HER2-, PIK3CAmut breast cancer patients treated with a PI3K inhibitor., (© 2023 Genentech, Inc and The Authors. Molecular Oncology published by John Wiley & Sons Ltd on behalf of Federation of European Biochemical Societies.)

Background: The HER2DX genomic test predicts pathological complete response (pCR) and survival outcome in early-stage HER2-positive (HER2+) breast cancer. Here, we evaluated the association of HER2DX scores with (i) pCR according to hormone receptor status and various treatment regimens, and (ii) survival outcome according to pCR status., Materials and Methods: Seven neoadjuvant cohorts with HER2DX and clinical individual patient data were evaluated (DAPHNe, GOM-HGUGM-2018-05, CALGB-40601, ISPY-2, BiOnHER, NEOHER and PAMELA). All patients were treated with neoadjuvant trastuzumab (n = 765) in combination with pertuzumab (n = 328), lapatinib (n = 187) or without a second anti-HER2 drug (n = 250). Event-free survival (EFS) and overall survival (OS) outcomes were available in a combined series of 268 patients (i.e. NEOHER and PAMELA) with a pCR (n = 118) and without a pCR (n = 150). Cox models were adjusted to evaluate whether HER2DX can identify patients with low or high risk beyond pCR status., Results: HER2DX pCR score was significantly associated with pCR in all patients [odds ratio (OR) per 10-unit increase = 1.59, 95% confidence interval 1.43-1.77; area under the ROC curve = 0.75], with or without dual HER2 blockade. A statistically significant increase in pCR rate due to dual HER2 blockade over trastuzumab-only was observed in HER2DX pCR-high tumors treated with chemotherapy (OR = 2.36 (1.09-5.42). A statistically significant increase in pCR rate due to multi-agent chemotherapy over a single taxane was observed in HER2DX pCR-medium tumors treated with dual HER2 blockade (OR = 3.11, 1.54-6.49). The pCR rates in HER2DX pCR-low tumors were ≤30.0% regardless of treatment administered. After adjusting by pCR status, patients identified as HER2DX low-risk had better EFS (P < 0.001) and OS (P = 0.006) compared with patients with HER2DX high-risk., Conclusions: HER2DX pCR score and risk score might help identify ideal candidates to receive neoadjuvant dual HER2 blockade in combination with a single taxane in early-stage HER2+ breast cancer., (Copyright © 2023 European Society for Medical Oncology. Published by Elsevier Ltd. All rights reserved.)

Introduction: Tumor-infiltrating lymphocytes (TILs) have predictive and prognostic value in breast cancer (BC) and exert a protective function against tumor growth, indicating that it is susceptible to treatment using adoptive cell transfer of TILs or T cell receptor (TCR)-based therapies. TCR can be used to identify naturally tumor-reactive T cells, but little is known about the differences in the TCR repertoires of CD4+ and CD8+ TILs., Methods: TCR high-throughput sequencing was performed using TILs derived from the initial cultures of 11 BC biopsies and expanded and sorted CD4+ and CD8+ TILs as well as using PBMCs from healthy donors expanded and sorted using the same methodology., Results: Physicochemical TCR differences between T cell subsets were observed, as CD4+ TILs presented larger N(D)Nnt TRB sequences and with a higher usage of positively charged residues, although only the latest was also observed in peripheral T cells from healthy individuals. Moreover, in CD4+ TILs, a more restricted TCR repertoire with a higher abundance of similar sequences containing certain amino acid motifs was observed., Discussion: Some differences between CD4+ and CD8+ TCRs were intrinsic to T cell subsets as can also be observed in peripheral T cells from healthy individuals, while other were only found in TILs samples and therefore may be tumor-driven. Notably, the higher similarity among CD4+ TCRs suggests a higher TCR promiscuity in this subset., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Aran, Lázaro, Marco, Molina, Abancó, Peg, Gión, Garrigós, Pérez-García, Cortés and Martí.)

Purpose: Metastatic hormone receptor-positive (HR+) breast cancer initially responds to serial courses of endocrine therapy, but ultimately becomes refractory. Elacestrant, a new generation FDA-approved oral selective estrogen receptor degrader (SERD) and antagonist, has demonstrated efficacy in a subset of women with advanced HR+breast cancer, but there are few patient-derived models to characterize its effect in advanced cancers with diverse treatment histories and acquired mutations., Methods: We analyzed clinical outcomes with elacestrant, compared with endocrine therapy, among women who had previously been treated with a fulvestrant-containing regimen from the recent phase 3 EMERALD Study. We further modeled sensitivity to elacestrant, compared with the currently approved SERD, fulvestrant in patient-derived xenograft (PDX) models and cultured circulating tumor cells (CTCs)., Results: Analysis of the subset of breast cancer patients enrolled in the EMERALD study who had previously received a fulvestrant-containing regimen indicates that they had better progression-free survival with elacestrant than with standard-of-care endocrine therapy, a finding that was independent estrogen receptor (ESR1) gene mutations. We modeled elacestrant responsiveness using patient-derived xenograft (PDX) models and in ex vivo cultured CTCs derived from patients with HR+breast cancer extensively treated with multiple endocrine therapies, including fulvestrant. Both CTCs and PDX models are refractory to fulvestrant but sensitive to elacestrant, independent of mutations in ESR1 and Phosphatidylinositol-4,5-Bisphosphate 3-Kinase Catalytic Subunit Alpha (PIK3CA) genes., Conclusion: Elacestrant retains efficacy in breast cancer cells that have acquired resistance to currently available ER targeting therapies. Elacestrant may be an option for patients with HR+/HER2- breast cancer whose disease progressed on fulvestrant in the metastatic setting., Translational Relevance: Serial endocrine therapy is the mainstay of management for metastatic HR+breast cancer, but acquisition of drug resistance highlights the need for better therapies. Elacestrant is a recently FDA-approved novel oral selective estrogen receptor degrader (SERD), with demonstrated efficacy in the EMERALD phase 3 clinical trial of refractory HR+breast cancer. Subgroup analysis of the EMERALD clinical trial identifies clinical benefit with elacestrant in patients who had received prior fulvestrant independent of the mutational status of the ESR1 gene, supporting its potential utility in treating refractory HR+breast cancer. Here, we use pre-clinical models, including ex vivo cultures of circulating tumor cells and patient-derived xenografts, to demonstrate the efficacy of elacestrant in breast cancer cells with acquired resistance to fulvestrant., (© 2023. The Author(s).)

Although breast cancer has led the way toward precision medicine, more research is still needed to increase curation rates in patients with early disease and to prolong survival with an optimal quality of life in the metastatic setting. Last year, big advances were achieved toward these goals thanks to the significant impact of immunotherapy on survival in triple-negative breast cancer and the exciting results of antibody-drug conjugates. PLAIN LANGUAGE SUMMARY: The development of new drugs and biomarkers to select those patients who will benefit of them are crucial in improving survival in breast cancer. Last year, the emergence of antibody-drug conjugates and the reaffirmation of the potential of immunotherapy in breast cancer were the most important findings., (© 2023 The Authors. Cancer published by Wiley Periodicals LLC on behalf of American Cancer Society.)

The utility of multigene expression assays in advanced (≥ 4 positive lymph nodes) early breast cancer (EBC) is limited. We conducted exploratory transcriptomic analysis of 758 genes (Breast Cancer 360 panel, nCounter ® platform; NanoString) in primary tumor samples collected during a phase 3 trial comparing adjuvant taxane-containing dose-dense chemotherapy (ddCTX) versus standard-dosed chemotherapy (stCTX) in resected EBC with ≥ 4 positive lymph nodes. Prognostic and predictive associations with disease-free survival (DFS) and overall survival (OS) were evaluated by Cox regression with false discovery rate (FDR) adjustment. Data were available from tumor samples of 141/226 patients (median follow-up: 14 years). Several genes/signatures, including immune markers, showed prognostic relevance in unadjusted analyses. Of these, two remained significant after multiplicity adjustment: a positive effect on DFS of programmed cell death 1 ligand-2 (PD-L2) in the ddCTX arm (univariate HR: 0.53, FDR-adjusted P = 0.036) and a negative effect on OS of HER2-enriched (HER2-E) signature in the stCTX arm (univariate HR: 5.40, FDR-adjusted P = 0.036). Predictive analyses showed greater DFS benefit of ddCTX in tumors with high antigen processing machinery (APM) expression (multivariate interaction P = 0.024). Multigene expression assays have a prognostic and predictive potential in advanced EBC, and further investigation is warranted in order to identify candidates for de-escalated treatment. In addition, intrinsic subtype and immune gene expression have predictive potential., (© 2023 The Authors. Molecular Oncology published by John Wiley & Sons Ltd on behalf of Federation of European Biochemical Societies.)

Breast cancer continues to be the leading cause of death in women worldwide. Mammography, which is the current gold standard technique used to diagnose it, presents strong limitations in early ages where breast cancer is much more aggressive and fatal. MiRNAs present in numerous body fluids might represent a new line of research in breast cancer biomarkers, especially oncomiRNAs, known to play an important role in the suppression and development of neoplasms. The aim of this systematic review and meta-analysis was to evaluate dysregulated miRNA biomarkers and their diagnostic accuracy in breast cancer. Two independent researchers reviewed the included studies according to the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. A protocol for this review was registered in PROSPERO with the registration number "CRD42021256338". Observational case-control-based studies analyzing concentrations of microRNAs which have been published within the last 10 years were selected, and the concentrations of miRNAs in women with breast cancer and healthy controls were analyzed. Random-effects meta-analyses of miR-155 were performed on the studies which provided enough data to calculate diagnostic odds ratios. We determined that 34 microRNAs were substantially dysregulated and could be considered biomarkers of breast cancer. Individually, miR-155 provided better diagnostic results than mammography on average. However, when several miRNAs are used to screen, forming a panel, sensitivity and specificity rates improve, and they can be associated with classic biomarkers such us CA-125 or CEA. Based on the results of our meta-analysis, miR-155 might be a promising diagnostic biomarker for this patient population.

Background: Mutations in the p110α catalytic subunit of phosphatidylinositol 3-kinase (PI3K), encoded by the PIK3CA gene, cause dysregulation of the PI3K pathway in 35-40% of patients with HR+/HER2- breast cancer. Preclinically, cancer cells harboring double or multiple PIK3CA mutations (mut) elicit hyperactivation of the PI3K pathway leading to enhanced sensitivity to p110α inhibitors., Methods: To understand the role of multiple PIK3CAmut in predicting response to p110α inhibition, we estimated the clonality of multiple PIK3CAmut in circulating tumor DNA (ctDNA) from patients with HR+/HER2- metastatic breast cancer enrolled to a prospectively registered clinical trial of fulvestrant ± taselisib, and analyzed the subgroups against co-altered genes, pathways, and outcomes., Results: ctDNA samples with clonal multiple PIK3CAmut had fewer co-alterations in receptor tyrosine kinase (RTK) or non-PIK3CA PI3K pathway genes compared to samples with subclonal multiple PIK3CAmut indicating a strong reliance on the PI3K pathway. This was validated in an independent cohort of breast cancer tumor specimens that underwent comprehensive genomic profiling. Furthermore, patients whose ctDNA harbored clonal multiple PIK3CAmut exhibited a significantly higher response rate and longer progression-free survival vs subclonal multiple PIK3CAmut., Conclusions: Our study establishes clonal multiple PIK3CAmut as an important molecular determinant of response to p110α inhibition and provides rationale for further clinical investigation of p110α inhibitors alone or with rationally-selected therapies in breast cancer and potentially other solid tumor types., (© 2023. The Author(s).)

Importance: Trastuzumab has been the standard of care for the treatment of patients with ERBB2-positive breast cancer; however, cardiac events have been reported. This long-term follow-up study provides clinical evidence supporting the similarity of a trastuzumab biosimilar (SB3) to reference trastuzumab (TRZ)., Objective: To compare cardiac safety and efficacy between SB3 and TRZ for patients with ERBB2-positive early or locally advanced breast cancer after up to 6 years of follow-up., Design, Setting, and Participants: This prespecified secondary analysis of a randomized clinical trial, conducted from April 2016 to January 2021, included patients with ERBB2-positive early or locally advanced breast cancer from a multicenter double-blind, parallel-group, equivalence phase 3 randomized clinical trial of SB3 vs TRZ with concomitant neoadjuvant chemotherapy who completed neoadjuvant and adjuvant treatment., Interventions: In the original trial, patients were randomized to either SB3 or TRZ with concomitant neoadjuvant chemotherapy for 8 cycles (4 cycles of docetaxel followed by 4 cycles of fluorouracil, epirubicin, and cyclophosphamide). After surgery, patients continued SB3 or TRZ monotherapy for 10 cycles of adjuvant treatment per previous treatment allocation. Following neoadjuvant and adjuvant treatment, patients were monitored for up to 5 years., Main Outcomes and Measures: The primary outcomes were the incidence of symptomatic congestive heart failure and asymptomatic, significant decrease in left ventricular ejection fraction (LVEF). The secondary outcomes were event-free survival (EFS) and overall survival (OS)., Results: A total of 538 female patients were included (median age, 51 years [range, 22-65 years]). Baseline characteristics were comparable between the SB3 and TRZ groups. Cardiac safety was monitored for 367 patients (SB3, n = 186; TRZ, n = 181). Median follow-up was 68 months (range, 8.5-78.1 months). Asymptomatic, clinically significant LVEF decreases were rarely reported (SB3, 1 patient [0.4%]; TRZ, 2 [0.7%]). No patient experienced symptomatic cardiac failure or death due to a cardiovascular event. Survival was evaluated for the 367 patients in the cardiac safety cohort and an additional 171 patients enrolled after a protocol amendment (538 patients [SB3, n = 267; TRZ, n = 271]). No difference was observed in EFS or OS between treatment groups (EFS: hazard ratio [HR], 0.84; 95% CI, 0.58-1.20; P = .34; OS: HR, 0.61; 95% CI, 0.36-1.05; P = .07). Five-year EFS rates were 79.8% (95% CI, 74.8%-84.9%) in the SB3 group and 75.0% (95% CI, 69.7%-80.3%) in the TRZ group, and OS rates were 92.5% (95% CI, 89.2%-95.7%) in the SB3 group and 85.4% (95% CI, 81.0%-89.7%) in the TRZ group., Conclusions and Relevance: In this secondary analysis of a randomized clinical trial, SB3 demonstrated cardiac safety and survival comparable to those of TRZ after up to 6 years of follow-up in patients with ERBB2-positive early or locally advanced breast cancer., Trial Registration: ClinicalTrials.gov Identifier: NCT02771795.

Importance: Both tumor-infiltrating lymphocytes (TILs) assessment and immune-related gene expression signatures by RNA profiling predict higher pathologic complete response (pCR) and improved event-free survival (EFS) in patients with early-stage ERBB2/HER2-positive breast cancer. However, whether these 2 measures of immune activation provide similar or additive prognostic value is not known., Objective: To examine the prognostic ability of TILs and immune-related gene expression signatures, alone and in combination, to predict pCR and EFS in patients with early-stage ERBB2/HER2-positive breast cancer treated in 2 clinical trials., Design, Setting, and Participants: In this prognostic study, a correlative analysis was performed on the Cancer and Leukemia Group B (CALGB) 40601 trial and the PAMELA trial. In the CALGB 40601 trial, 305 patients were randomly assigned to weekly paclitaxel with trastuzumab, lapatinib, or both for 16 weeks. The primary end point was pCR, with a secondary end point of EFS. In the PAMELA trial, 151 patients received neoadjuvant treatment with trastuzumab and lapatinib for 18 weeks. The primary end point was the ability of the HER2-enriched subtype to predict pCR. The studies were conducted from October 2013 to November 2015 (PAMELA) and from December 2008 to February 2012 (CALGB 40601). Data analyses were performed from June 1, 2020, to January 1, 2022., Main Outcomes and Measures: Immune-related gene expression profiling by RNA sequencing and TILs were assessed on 230 CALGB 40601 trial pretreatment tumors and 138 PAMELA trial pretreatment tumors. The association of these biomarkers with pCR (CALGB 40601 and PAMELA) and EFS (CALGB 40601) was studied by logistic regression and Cox analyses., Results: The median age of the patients was 50 years (IQR, 42-50 years), and 305 (100%) were women. Of 202 immune signatures tested, 166 (82.2%) were significantly correlated with TILs. In both trials combined, TILs were significantly associated with pCR (odds ratio, 1.01; 95% CI, 1.01-1.02; P = .02). In addition to TILs, 36 immune signatures were significantly associated with higher pCR rates. Seven of these signatures outperformed TILs for predicting pCR, 6 of which were B-cell related. In a multivariable Cox model adjusted for clinicopathologic factors, including PAM50 intrinsic tumor subtype, the immunoglobulin G signature, but not TILs, was independently associated with EFS (immunoglobulin G signature-adjusted hazard ratio, 0.63; 95% CI, 0.42-0.93; P = .02; TIL-adjusted hazard ratio, 1.00; 95% CI, 0.98-1.02; P = .99)., Conclusions and Relevance: Results of this study suggest that multiple B-cell-related signatures were more strongly associated with pCR and EFS than TILs, which largely represent T cells. When both TILs and gene expression are available, the prognostic value of immune-related signatures appears to be superior.

Background: Palbociclib has gained a central role in the treatment of hormone receptor-positive (HR+)/human epidermal growth factor receptor 2-negative (HER2-) advanced breast cancer (ABC). Despite its manageable toxicity profile, venous thromboembolism (VTE) or interstitial lung disease (ILD)/pneumonitis may infrequently occur. Therefore, we provide a comprehensive summary of the safety and tolerability of the combination of endocrine therapy and palbociclib among patients included in the randomized phase 2 PARSIFAL study., Materials and Methods: Patients with endocrine-sensitive HR+/HER2- ABC and no prior therapy in an advanced setting (n = 486) were randomly assigned 1:1 to receive fulvestrant-palbociclib (FP) or letrozole-palbociclib (LP). Laboratory tests and the incidence of adverse events (AEs) were recorded at baseline and day 1 of each cycle. Progression-free survival (PFS) was estimated for patients with and without VTE., Results: A total of 483 patients were analyzed. Neutropenia, leukopenia, anemia, asthenia, arthralgia, fatigue, and diarrhea were the most frequent AEs in both groups. Febrile neutropenia occurred in 3 (1.2%) patients of the FP group and in 1 (0.4%) patient in the LP group. Six (2.5%; 0.4% grade 3) patients in the FP group and 6 patients (2.5%; 0.4% grade 3) in the LP group experienced ILD/pneumonitis. Pulmonary embolism was reported in 12 (5.0%) patients in the FP group and 6 (2.5%) patients in the LP group. Advanced age at baseline was the only factor significantly associated with an increased risk of pulmonary embolism (P < .01)., Conclusion: The PARSIFAL data confirmed the favorable safety profile of both palbociclib regimens. VTE and ILD/pneumonitis were occasionally reported, and their early detection allowed patients to continue treatment effectively without detriment to efficacy., Clinicaltrials.gov Identifier: NCT02491983; https://clinicaltrials.gov/ct2/show/NCT02491983)., (© The Author(s) 2022. Published by Oxford University Press.)

Background: An improvement in progression-free survival was shown with trastuzumab deruxtecan versus trastuzumab emtansine in patients with HER2-positive metastatic breast cancer in the progression-free survival interim analysis of the DESTINY-Breast03 trial. The aim of DESTINY-Breast03 was to compare the efficacy and safety of trastuzumab deruxtecan versus trastuzumab emtansine., Methods: This open-label, randomised, multicentre, phase 3 trial was done in 169 study centres in North America, Asia, Europe, Australia, and South America. Eligible patients were aged 18 or older, had HER2-positive unresectable or metastatic breast cancer previously treated with trastuzumab and a taxane, had an Eastern Cooperative Oncology Group performance status 0-1, and at least one measurable lesion per Response Evaluation Criteria in Solid Tumours version 1.1. Patients were randomly assigned (1:1) to receive trastuzumab deruxtecan 5·4 mg/kg or trastuzumab emtansine 3·6 mg/kg, both administered by intravenous infusion every 3 weeks. Randomisation was stratified by hormone receptor status, previous treatment with pertuzumab, and history of visceral disease, and was managed through an interactive web-based system. Within each stratum, balanced block randomisation was used with a block size of four. Patients and investigators were not masked to the treatment received. The primary endpoint was progression-free survival by blinded independent central review. The key secondary endpoint was overall survival and this prespecified second overall survival interim analysis reports updated overall survival, efficacy, and safety results. Efficacy analyses were performed using the full analysis set. Safety analyses included all randomly assigned patients who received at least one dose of study treatment. This study is registered with ClinicalTrials.gov, NCT03529110., Findings: Between July 20, 2018, and June 23, 2020, 699 patients were screened for eligibility, 524 of whom were enrolled and randomly assigned to receive trastuzumab deruxtecan (n=261) or trastuzumab emtansine (n=263). Median duration of study follow-up was 28·4 months (IQR 22·1-32·9) with trastuzumab deruxtecan and 26·5 months (14·5-31·3) with trastuzumab emtansine. Median progression-free survival by blinded independent central review was 28·8 months (95% CI 22·4-37·9) with trastuzumab deruxtecan and 6·8 months (5·6-8·2) with trastuzumab emtansine (hazard ratio [HR] 0·33 [95% CI 0·26-0·43]; nominal p<0·0001). Median overall survival was not reached (95% CI 40·5 months-not estimable), with 72 (28%) overall survival events, in the trastuzumab deruxtecan group and was not reached (34·0 months-not estimable), with 97 (37%) overall survival events, in the trastuzumab emtansine group (HR 0·64; 95% CI 0·47-0·87]; p=0·0037). The number of grade 3 or worse treatment-emergent adverse events was similar in patients who received trastuzumab deruxtecan versus trastuzumab emtansine (145 [56%] patients versus 135 [52%] patients). Adjudicated drug-related interstitial lung disease or pneumonitis occurred in 39 (15%) patients treated with trastuzumab deruxtecan and eight (3%) patients treated with trastuzumab emtansine, with no grade 4 or 5 events in either group., Interpretation: Trastuzumab deruxtecan showed a significant improvement in overall survival versus trastuzumab emtansine in patients with HER2-positive metastatic breast cancer, as well as the longest reported median progression-free survival, reaffirming trastuzumab deruxtecan as the standard of care in the second-line setting. A manageable safety profile of trastuzumab deruxtecan was confirmed with longer treatment duration., Funding: Daiichi Sankyo and AstraZeneca., Competing Interests: Declaration of interests SAH has received support for the present manuscript from Daiichi Sankyo and AstraZeneca; has received grants or contracts from Ambrx, Amgen, Arvinas, Bayer, Cytomx, Dantar, Dignitana, Genentech/Roche, G1-Therapeutics, Gilead, GSK, Immunomedics, Eli Lilly, Macrogenics, Novartis, OBI, Pharma, Orinove, Pfizer, Phoenix Molecular Designs, Pieris, PUMA, Radius, Samumed, Sanofi, Seattle Genetics/Seagen, and Zymeworks; has received payment or honoraria for lectures, presentations, speaker bureaus, manuscript writing, or educational events from Daiichi Sankyo and continuing medical education (CME) companies (PER, Clinical Care Options, Research to Practice, etc); has received support for attending meetings or travel from San Antonio Breast Cancer Symposium, American Society of Clinical Oncology, National Comprehensive Cancer Network, and CME companies (PER, Clinical Care Options, and Research to Practice); has participated as a data safety monitoring board member for the I-SPY trial (unpaid); and has served a leadership or fiduciary role in another board for TRIO-US (unpaid chief medical officer of site management organisation). W-PC has received payment or honoraria for lectures and presentations from Amgen, AstraZeneca, Daiichi Sankyo, Eli Lilly, Everest Medicine, Foundation Medicine, Kyowa Kirin, MSD, Novartis, Pfizer, Roche, and Sanofi; has received support for attending meetings from Amgen, AstraZeneca, Pfizer, and Roche; has participated in advisory boards for Amgen, AstraZeneca, Daiichi Sankyo, Eli Lilly, Everest Medicine, MSD, Novartis, and Roche; and has participated in a data safety monitoring board for AstraZeneca. S-AI has received grants or contracts from AstraZeneca, Eisai, Daewoong Pharm, Daiichi Sankyo, Pfizer, Roche, and Boryung Pharm; and has received consulting fees from AstraZeneca, Hanmi, Eisai, Lilly, MSD, Idience, Novartis, Pfizer, Roche, GSK, Daiichi Sankyo, and Bertis. WJ has received grants or contracts from AstraZeneca and Daiichi Sankyo; has received support for attending meetings or travel from AstraZeneca, Eisai, Lilly France, Pfizer, Roche, Chugai Pharma, GlaxoSmithKline, Novartis, Pierre Fabre, and Sanofi Aventis; and has participated on a data safety monitoring board or advisory board for AstraZeneca, Eisai, Lilly France, Pfizer, Roche, BMS, Daiichi Sankyo, Novartis, MSD, and Seagen. JWYC has received honoraria for manuscript writing from Daiichi Sankyo. BX has received payment or honoraria for lectures and presentations from AstraZeneca, Pfizer Inc, Roche, and Eisai. EH has received institutional support for the present manuscript from Daiichi Sankyo and AstraZeneca; has received institutional grants or contracts from AbbVie, Acerta Pharma, Accutar Biotechnology, ADC Therapeutics, AKESOBIO Australia, Amgen, Aravive, ArQule, Artios, Arvinas, AtlasMedx, Black Diamond, Bliss BioPharmaceuticals, Boehringer Ingelheim, Cascadian Therapeutics, Clovis, Compugen, Cullen-Florentine, Curis, CytomX, Dana Farber Cancer Institute, Dantari, Deciphera, Duality Biologics, eFFECTOR Therapeutics, Ellipses Pharma, Elucida Oncology, EMD Serono, Fochon, FujiFilm, G1 Therapeutics, H3 Biomedicine, Harpoon, Hutchinson MediPharma, Immunogen, Immunomedics, Incyte, Infinity Pharmaceuticals, InvestisBio, Jacobio, Karyopharm, Leap Therapeutics, Lilly, Lycera, Mabspace Biosciences, Macrogenics, MedImmune, Merck, Mersana, Merus, Millenium, Molecular Templates, Myriad Genetic Laboratories, Novartis, Nucana, Olema, OncoMed, Onconova Therapeutics, ORIC Pharmaceuticals, Orinove, Pfizer, PharmaMar, Pieris Pharmaceuticals, Pionyr Immunotherapeutics, Plexxikon, Radius Health, Regeneron, Relay Therapeutics, Repertoire Immune Medicine, Rgenix, Roche/Genentech, Seagen, Sermonix Pharmaceuticals, Shattuck Labs, Silverback, StemCentRx, Sutro, Syndax, Syros, Taiho, TapImmune, Tesaro, Tolmar, Torque Therapeutics, Treadwell Therapeutics, Verastem, Vincerx Pharma, Zenith Epigenetics, and Zymeworks; and has received consulting fees paid to the institution from Arcus, Eisai, Greenwich Lifesciences, H3 Biomedicine, iTeos, Janssen, Loxo, Orum Therapeutics, Propella Therapeutics, Puma Biotechnology, Arvinas, Black Diamond, Boehringer Ingelheim, CytomX, Dantari, Deciphera, Lilly, Merck, Mersana, Novartis, Pfizer, Relay Therapeutics, Roche/Genentech, Seagen, and Silverback. SM received consulting fees, support for attending meetings or travel, and participated in an advisory board for Daiichi Sankyo. HI has received consulting fees from Daicihi Sankyo, Chugai, AstraZeneca, Sanofi, Lilly, MSD, Pfizer, and Novartis; and payment or honoraria from Daiichi Sankyo, Chugai, AstraZeneca, Lilly, MSD, and Pfizer. SAl has received institutional payment for advisory boards from Eli Lilly, Pfizer, MSD, AstraZeneca, Novartis, and Bayer; institutional grants from Roche and Sanofi; and received travel and accommodations from Pfizer, Roche, PharmaMar, Novartis, AstraZeneca, Bayer, and Gilead. J-WH has received support for the present manuscript from AstraZeneca and Daiichi Sankyo; has received consulting fees from Novartis, Pfizer, Eli Lilly, Roche, AstraZeneca, Gilead Science, Knight Therapeutic; and has received payment or honoraria for lectures, presentations, speaker bureaus, manuscript writing, or educational events from Novartis and AstraZeneca. GC has received support for the present manuscript from AstraZeneca and Daiichi Sankyo; has received grants or contracts from Merck and AstraZeneca; has received consulting fees from Roche, BMS, Novartis, Lilly, Pfizer, Seagen, AstraZeneca, Ellipsis, Gilead, Merck, Celcuity, Sanofi, Exact Sciences, and Daiichi Sankyo; has received payment or honoraria for presentations, lectures, speaker bureaus, manuscript writing, or educational events from Novartis, Lilly, Pfizer, Seagen, and Daiichi Sankyo; has received support for attending meetings or travel from AstraZeneca and Daiichi Sankyo; and has participated on a data safety monitoring board or advisory board for Roche, BMS, Novartis, Lilly, Pfizer, Seagen, Ellipsis, Gilead, Merck, Celcuity, AstraZeneca, and Daiichi Sankyo. JMP-G has received consulting fees from Roche/AstraZeneca, Daiichi Sankyo, Lilly/Eisai, and Seattle Genetics and has received support for attending meetings or travel from Roche. S-BK has received institutional grants or contracts from Novartis, Sanofi Aventis, and DongKook Pharmaceutical; has received consulting fees from Novartis, AstraZeneca, Lilly, DaeHwa Pharmaceutical, ISU Abxis, Beigene, OBI Pharma, and Daiichi Sankyo; has received payment or honoraria for lectures, presentations, speaker bureaus, manuscript writing, or educational events from Novartis, Pfizer, OBI Pharma, and Legochem Bioscience; has participated on a data safety monitoring board or advisory board for Novartis, AstraZeneca, MSD, Lilly, and Daiichi Sankyo; and has purchased stock or stock options from Genopeaks and NeoGene TC. VP has received consulting fees for advisory boards from Daiichi Sankyo; has received fees for non-CME services received directly from commercial interests or their agents for speakers' bureaus from AstraZeneca, Novartis, Daiichi Sankyo, and Pfizer; and has received travel support for congresses from Roche and Daiichi Sankyo. C-SH has received research grants to his institution for the present manuscript from Daiichi Sankyo; has received institutional grants or contracts from Daiichi Sankyo, AstraZeneca, EirGenix, Eli Lilly, MSD, OBI Pharma, Pfizer, Roche, Novartis; has received payment or honoraria for speakers bureaus from Daiichi Sankyo, AstraZeneca, Pfizer, Novartis, Roche; has received support for travel from AstraZeneca, Pfizer, Roche, and Novartis; and has participated on advisory boards for Daiichi Sankyo, AstraZeneca, Eli Lilly, Pfizer, Novartis, and Roche. J-SF has received consulting fees from Pfizer, Lilly, Novartis, AstraZeneca, Clovis Oncology, GSK, Gilead, Daiichi Sankyo, and Seagen; has received payment or honoraria for lectures, presentations, speaker bureaus, manuscript writing, or educational events from Lilly, Novartis, AstraZeneca, Gilead, Daiichi Sankyo, and Seagen; and has received support for attending meetings or travel from Pfizer, Lilly, Novartis, AstraZeneca, Clovis Oncology, GSK, Gilead, Daiichi Sankyo, and Seagen. SAn has received consulting fees for advisory boards from Roche, Daiichi Sankyo, Pierre Fabre, and Lilly; and has received fees for non-CME services received directly from commercial interest or their agents (eg, speakers' bureaus) from Roche, Pierre Fabre, and Pfizer. WY has received payment or honoraria for lectures, presentations, advisory boards or educational events from Roche, AstraZeneca, Daiichi Sankyo, Lilly, MSD, Mundipharma, Eisai, and Novartis. GB has received consulting fees from Roche, AstraZeneca, MSD, Daiichi Sankyo, Gilead, Sanofi, and Seagen; has received payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing, or educational events from Roche, AstraZeneca, Daiichi Sankyo, Lilly, MSD, Chugai, Eisai, Gilead, and Seagen; has received support for attending meetings or travel from Roche, Pfizer, MSD, Chugai, Novartis, and AstraZeneca; and has participated on a data safety monitoring board or advisory board for Roche, Pfizer, AstraZeneca, Lilly, Novartis, Amgen, MSD, Chugai, Daiichi Sankyo, Eisai, Gilead, Seagen, Exact Science, and Agendia. SL has received institutional grants or contracts from Novartis, Bristol Myers Squibb, Merck, Puma Biotechnology, Eli Lilly, Nektar Therapeutics, AstraZeneca, Roche-Genentech, and Seattle Genetics; has received consulting fees paid to her institution from Aduro Biotech, Novartis, GlaxoSmithKline, Roche-Genentech, AstraZeneca, Silverback Therapeutics, G1 Therapeutics, PUMA Biotechnologies, Pfizer, Gilead Therapeutics, Seattle Genetics, Daiichi Sankyo, Merck, Amunix, Tallac Therapeutics, Eli Lilly, and Bristol Myers Squibb; and serves as a consultant (not paid) for Seattle Genetics, Novartis, Bristol Myers Squibb, Merck, AstraZeneca, Eli Lilly, Pfizer, Gilead Therapeutics, and Roche-Genentech. JT has received support for the present manuscript in the form of grants, contracts, or consulting fees from Daiichi Sankyo and AstraZeneca; has received payment or honoraria for lectures from Daiichi Sankyo and AstraZeneca; has received payment for expert testimony from Daiichi Sankyo and Taiho; has received support for attending meetings or travel from Daiichi Sankyo and Chugai; and has served as an advisor for West Japan Oncology Group. AE, YL, JCa, and SAs are employees of Daiichi Sankyo and AE and YL have stock in Daiichi Sankyo. JCo has received support for the present manuscript from Daiichi Sankyo and AstraZeneca; has received institutional grants or contracts from Roche, Ariad Pharmaceuticals, AstraZeneca, Baxalta GMBH/Servier Affaires, Bayer Healthcare, Eisai, F Hoffman-La Roche, Guardant Health, Merck Sharp & Dohme, Pfizer, Piqur Therapeutics, Puma C, and Queen Mary University of London; has received consulting fees from Roche, Celgene, Cellestia, AstraZeneca, Seattle Genetics, Daiichi Sankyo, Erytech, Athenex, Polyphor, Lilly, Merck Sharp & Dohme, GSK, Leuko, Bioasis, Clovis Oncology, Boehringer Ingelheim, Ellipses, Hibercell, BioInvent, Gemoab, Gilead, Menarini, Zymeworks, and Reveal Genomics; has received payment or honoraria for lectures, presentations, speaker bureaus, manuscript writing, or educational events from Roche, Novartis, Celgene, Eisai, Pfizer, Samsung Bioepis, Lilly, Merck Sharp & Dohme, and Daiichi Sankyo; has received support for attending meetings or travel from Roche, Novartis, Eisai, Pfizer, Daiichi Sankyo, AstraZeneca, and Gilead; has patents planned, issued, or pending (WO 2014/199294 A; US 2019/ 0338368 A1); and has stock or stock options with MedSIR, Nektar Pharmaceuticals, and Leuko. All other authors declare no completing interests., (Copyright © 2023 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY-NC-ND 4.0 license. Published by Elsevier Ltd.. All rights reserved.)

Background: Trastuzumab deruxtecan (T-DXd) has shown durable antitumor activity in pretreated patients with HER2-positive advanced breast cancer (ABC), but its efficacy has not yet been evaluated in patients with active brain metastases (BMs). DEBBRAH aims to assess T-DXd in patients with HER2-positive or HER2-low ABC and central nervous system involvement., Methods: This ongoing, five-cohort, phase II study (NCT04420598) enrolled patients with pretreated HER2-positive or HER2-low ABC with stable, untreated, or progressing BMs, and/or leptomeningeal carcinomatosis. Here, we report findings from HER2-positive ABC patients with non-progressing BMs after local therapy (n = 8; cohort 1), asymptomatic untreated BMs (n = 4; cohort 2), or progressing BMs after local therapy (n = 9; cohort 3). Patients received 5.4 mg/kg T-DXd intravenously once every 21 days. The primary endpoint was 16-week progression-free survival (PFS) for cohort 1 and intracranial objective response rate (ORR-IC) for cohorts 2 and 3., Results: As of October 20, 2021, 21 patients received T-DXd. In cohort 1, 16-week PFS rate was 87.5% (95%CI, 47.3-99.7; P < .001). ORR-IC was 50.0% (95%CI, 6.7-93.2) in cohort 2 and 44.4% (95%CI, 13.7-78.8; P < .001) in cohort 3. Overall, the ORR-IC in patients with active BMs was 46.2% (95%CI, 19.2-74.9). Among patients with measurable intracranial or extracranial lesions at baseline, the ORR was 66.7% (12 out of 18 patients; 95%CI, 41.0-86.7), 80.0% (95%CI, 28.4-99.5) in cohort 1, 50.0% (95%CI, 6.7-93.2) in cohort 2, and 66.7% (95%CI, 29.9-92.5) in cohort 3. All responders had partial responses. The most common adverse events included fatigue (52.4%; 4.8% grade ≥3), nausea (42.9%; 0% grade ≥3), neutropenia (28.6%; 19% grade ≥3), and constipation (28.6%; 0% grade ≥3). Two (9.5%) patients suffered grade 1 interstitial lung disease/pneumonitis., Conclusions: T-DXd showed intracranial activity with manageable toxicity and maintained the quality of life in pretreated HER2-positive ABC patients with stable, untreated, or progressing BMs. Further studies are needed to validate these results in larger cohorts., (© The Author(s) 2022. Published by Oxford University Press on behalf of the Society for Neuro-Oncology.)

Purpose: To assess the efficacy and exploratory biomarkers of continuing palbociclib plus endocrine therapy (ET) beyond progression on prior palbociclib-based regimen in patients with hormone receptor-positive/HER2-negative (HR+/HER2-) advanced breast cancer (ABC)., Patients and Methods: The multicenter, open-label, phase II BioPER trial included women who had experienced a progressive disease (PD) after having achieved clinical benefit on the immediately prior palbociclib plus ET regimen. Palbociclib (125 mg, 100 mg, or 75 mg daily orally for 3 weeks and 1 week off as per prior palbociclib-based regimen) plus ET of physician's choice were administered in 4-week cycles until PD or unacceptable toxicity. Coprimary endpoints were clinical benefit rate (CBR) and percentage of tumors with baseline loss of retinoblastoma (Rb) protein expression. Additional endpoints included safety and biomarker analysis., Results: Among 33 patients enrolled, CBR was 34.4% [95% confidence interval (CI), 18.6-53.2; P < 0.001] and 13.0% of tumors (95% CI, 5.2-27.5) showed loss of Rb protein expression, meeting both coprimary endpoints. Median progression-free survival was 2.6 months (95% CI, 1.8-6.7). No new safety signals were reported. A signature that included baseline mediators of therapeutic resistance to palbociclib and ET (low Rb score, high cyclin E1 score, ESR1 mutation) was independently associated with shorter median progression-free survival (HR, 22.0; 95% CI, 1.71-282.9; P = 0.018)., Conclusions: Maintaining palbociclib after progression on prior palbociclib-based regimen seems to be a reasonable, investigational approach for selected patients. A composite biomarker signature predicts a subset of patients who may not derive a greater benefit from palbociclib rechallenge, warranting further validation in larger randomized controlled trials., (©2022 The Authors; Published by the American Association for Cancer Research.)

Antibody-drug conjugates (ADC) are antineoplastic agents recently introduced into the antitumor arsenal. T-DM1, a trastuzumab-based ADC that relies on lysosomal processing to release the payload, is approved for HER2-positive breast cancer. Next-generation ADCs targeting HER2, such as [vic-]trastuzumab duocarmazine (SYD985), bear linkers cleavable by lysosomal proteases and membrane-permeable drugs, mediating a bystander effect by which neighboring antigen-negative cells are eliminated. Many antitumor therapies, like DNA-damaging agents or CDK4/6 inhibitors, can induce senescence, a cellular state characterized by stable cell-cycle arrest. Another hallmark of cellular senescence is the enlargement of the lysosomal compartment. Given the relevance of the lysosome to the mechanism of action of ADCs, we hypothesized that therapies that induce senescence would potentiate the efficacy of HER2-targeting ADCs. Treatment with the DNA-damaging agent doxorubicin and CDK4/6 inhibitor induced lysosomal enlargement and senescence in several breast cancer cell lines. While senescence-inducing drugs did not increase the cytotoxic effect of ADCs on target cells, the bystander effect was enhanced when HER2-negative cells were cocultured with HER2-low cells. Knockdown experiments demonstrated the importance of cathepsin B in the enhanced bystander effect, suggesting that cathepsin B mediates linker cleavage. In breast cancer patient-derived xenografts, a combination treatment of CDK4/6 inhibitor and SYD985 showed improved antitumor effects over either treatment alone. These data support the strategy of combining next-generation ADCs targeting HER2 with senescence-inducing therapies for tumors with heterogenous and low HER2 expression., Significance: Combining ADCs against HER2-positive breast cancers with therapies that induce cellular senescence may improve their therapeutic efficacy by facilitating a bystander effect against antigen-negative tumor cells., (©2022 The Authors; Published by the American Association for Cancer Research.)

Background: We evaluated a new chemoimmunotherapy combination based on the anti-PD1 monoclonal antibody pembrolizumab and the pyrimidine antimetabolite gemcitabine in HER2- advanced breast cancer (ABC) patients previously treated in the advanced setting, in order to explore a potential synergism that could eventually obtain long term benefit in these patients., Methods: HER2-negative ABC patients received 21-day cycles of pembrolizumab 200 mg (day 1) and gemcitabine (days 1 and 8). A run-in-phase (6 + 6 design) was planned with two dose levels (DL) of gemcitabine (1,250 mg/m 2 [DL0]; 1,000 mg/m 2 [DL1]) to determine the recommended phase II dose (RP2D). The primary objective was objective response rate (ORR). Tumor infiltrating lymphocytes (TILs) density and PD-L1 expression in tumors and myeloid-derived suppressor cells (MDSCs) levels in peripheral blood were analyzed., Results: Fourteen patients were treated with DL0, resulting in RP2D. Thirty-six patients were evaluated during the first stage of Simon's design. Recruitment was stopped as statistical assumptions were not met. The median age was 52; 21 (58%) patients had triple-negative disease, 28 (78%) visceral involvement, and 27 (75%) ≥ 2 metastatic locations. Progression disease was observed in 29 patients. ORR was 15% (95% CI, 5-32). Eight patients were treated ≥ 6 months before progression. Fourteen patients reported grade ≥ 3 treatment-related adverse events. Due to the small sample size, we did not find any clear association between immune tumor biomarkers and treatment efficacy that could identify a subgroup with higher probability of response or better survival. However, patients that experienced a clinical benefit showed decreased MDSCs levels in peripheral blood along the treatment., Conclusion: Pembrolizumab 200 mg and gemcitabine 1,250 mg/m 2 were considered as RP2D. The objective of ORR was not met; however, 22% patients were on treatment for ≥ 6 months. ABC patients that could benefit of chemoimmunotherapy strategies must be carefully selected by robust and validated biomarkers. In our heavily pretreated population, TILs, PD-L1 expression and MDSCs levels could not identify a subgroup of patients for whom the combination of gemcitabine and pembrolizumab would induce long term benefit., Trial Registration: ClinicalTrials.gov and EudraCT (NCT03025880 and 2016-001,779-54, respectively). Registration dates: 20/01/2017 and 18/11/2016, respectively., (© 2022. The Author(s).)

Purpose: Patients with pretreated estrogen receptor (ER)-positive/human epidermal growth factor receptor 2 (HER2)-negative advanced breast cancer have poor prognosis. Elacestrant is a novel, oral selective ER degrader that demonstrated activity in early studies., Methods: This randomized, open-label, phase III trial enrolled patients with ER-positive/HER2-negative advanced breast cancer who had one-two lines of endocrine therapy, required pretreatment with a cyclin-dependent kinase 4/6 inhibitor, and ≤ 1 chemotherapy. Patients were randomly assigned to elacestrant 400 mg orally once daily or standard-of-care (SOC) endocrine monotherapy. Primary end points were progression-free survival (PFS) by blinded independent central review in all patients and patients with detectable ESR1 mutations., Results: Patients were randomly assigned to elacestrant (n = 239) or SOC (n = 238). ESR1 mutation was detected in 47.8% of patients, and 43.4% received two prior endocrine therapies. PFS was prolonged in all patients (hazard ratio = 0.70; 95% CI, 0.55 to 0.88; P = .002) and patients with ESR1 mutation (hazard ratio = 0.55; 95% CI, 0.39 to 0.77; P = .0005). Treatment-related grade 3/4 adverse events occurred in 7.2% receiving elacestrant and 3.1% receiving SOC. Treatment-related adverse events leading to treatment discontinuations were 3.4% in the elacestrant arm versus 0.9% in SOC. Nausea of any grade occurred in 35.0% receiving elacestrant and 18.8% receiving SOC (grade 3/4, 2.5% and 0.9%, respectively)., Conclusion: Elacestrant is the first oral selective ER degrader demonstrating a significant PFS improvement versus SOC both in the overall population and in patients with ESR1 mutations with manageable safety in a phase III trial for patients with ER-positive/HER2-negative advanced breast cancer.

Purpose: Sacituzumab govitecan (SG) is an antibody-drug conjugate composed of an anti-Trop-2 antibody coupled to SN-38 via a proprietary hydrolyzable linker. In the ASCENT study, SG improved survival versus single-agent treatment of physician's choice (TPC) in pre-treated metastatic triple-negative breast cancer (mTNBC). Hormone/HER2 receptor changes are common, particularly at relapse/metastasis. This subanalysis assessed outcomes in patients who did/did not have TNBC at initial diagnosis, before enrollment., Methods: TNBC diagnosis was only required at study entry. Patients with mTNBC refractory/relapsing after ≥ 2 prior chemotherapies were randomized 1:1 to receive SG or TPC. Primary endpoint was progression-free survival (PFS) in patients without brain metastases., Results: Overall, 70/235 (30%) and 76/233 (33%) patients who received SG and TPC, respectively, did not have TNBC at initial diagnosis. Clinical benefit with SG versus TPC was observed in this subset. Median PFS was 4.6 versus 2.3 months (HR 0.48; 95% CI 0.32-0.72), median overall survival was 12.4 versus 6.7 months (HR 0.44; 95% CI 0.30-0.64), and objective response rate (ORR) was 31% versus 4%; those who also received prior CDK4/6 inhibitors had ORRs of 21% versus 5%. Efficacy and safety for patients with TNBC at initial diagnosis were generally similar to those who did not present with TNBC at initial diagnosis., Conclusion: Patients without TNBC at initial diagnosis had improved clinical outcomes and a manageable safety profile with SG, supporting SG as a treatment option for mTNBC regardless of subtype at initial diagnosis. Subtype reassessment in advanced breast cancer allows for optimal treatment. Clinical trial registration number NCT02574455, registered October 12, 2015., (© 2022. The Author(s).)

Importance: Patients with breast cancer and brain metastases (BM) have a poor prognosis and high clinical need for novel treatments; however, historically, studies have often excluded these patients. Although the BEACON study did not meet its primary end point, treatment with etirinotecan pegol vs chemotherapy of the physician's choice for patients with advanced breast cancer demonstrated a significant improvement in overall survival (OS) for the prespecified patient subgroup with preexisting, pretreated, and nonprogressive BM., Objective: To compare clinical outcomes in patients with BM treated with etirinotecan pegol vs chemotherapy of the physician's choice in a confirmatory trial., Design, Setting, and Participants: This study was a phase 3, open-label, randomized clinical trial (ATTAIN) in patients with metastatic breast cancer and a history of stable pretreated BM who experienced disease progression while receiving chemotherapy in the metastatic setting. The trial took place at 47 sites in 10 countries, and patients were enrolled between March 7, 2017, and November 6, 2019., Interventions: Patients were randomized to receive etirinotecan pegol, 145 mg/m2, every 21 days or chemotherapy (eribulin, ixabepilone, vinorelbine, gemcitabine, paclitaxel, docetaxel, or nab-paclitaxel)., Main Outcomes and Measures: The primary end point was OS. Key secondary end points included progression-free survival, objective response rate, duration of response, and the clinical benefit rate., Results: A total of 178 female patients (9 [5.1%] Asian, 8 [4.5%] Black or African American, and 123 [69.1] White individuals) were randomized to receive treatment with etirinotecan pegol (92 [51.7%]; median [range] age, 53 [27-79] years) or chemotherapy (86 [48.3%]; median [range] age, 52 [24-77] years). Median OS was similar in both groups (etirinotecan pegol, 7.8 months; chemotherapy, 7.5 months; hazard ratio [HR], 0.90; 95% CI, 0.61-1.33; P = .60). Median progression-free survival for non-central nervous system metastases per blinded independent central review for etirinotecan pegol vs chemotherapy was 2.8 and 1.9 months (HR, 0.72; 95% CI, 0.45-1.16; P = .18) and 3.9 vs 3.3 months, respectively, for central nervous system metastases (HR, 0.59; 95% CI, 0.33-1.05; P = .07). Safety profiles between the groups were largely comparable., Conclusions and Relevance: The results of the ATTAIN randomized clinical trial found no statistically significant difference in outcomes between treatment with etirinotecan pegol and chemotherapy in patients with BM. However, this study represents one of the largest published trials dedicated to patients with breast cancer and BM and may help to inform further research., Trial Registration: ClinicalTrials.gov Identifier: NCT02915744.

Patients with HER2-positive breast cancer account for approximately 15% to 20% of all breast cancers and represent one of the most aggressive breast cancer subtypes. Survival rates of patients with metastatic disease have improved dramatically and progressively. Many new agents have been developed, and long-term follow-up from trials of anti-HER2 agents has shown long-term responses. The availability of novel, highly active anti-HER2 treatments, together with the ongoing development of promising diagnostic tools, will offer the unprecedented opportunity to raise cure rates. Our ultimate goal is to tailor treatment intensity to disease and patient characteristics, hopefully increasing the fraction of cured patients while minimizing the risk for overtreatment. If conducted rationally and carefully, this plan has the potential to break a decades-long paradigm, leading to a new, precise era of treatment of HER2-positive breast cancer.

Background: Trastuzumab emtansine is the current standard treatment for patients with human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer whose disease progresses after treatment with a combination of anti-HER2 antibodies and a taxane., Methods: We conducted a phase 3, multicenter, open-label, randomized trial to compare the efficacy and safety of trastuzumab deruxtecan (a HER2 antibody-drug conjugate) with those of trastuzumab emtansine in patients with HER2-positive metastatic breast cancer previously treated with trastuzumab and a taxane. The primary end point was progression-free survival (as determined by blinded independent central review); secondary end points included overall survival, objective response, and safety., Results: Among 524 randomly assigned patients, the percentage of those who were alive without disease progression at 12 months was 75.8% (95% confidence interval [CI], 69.8 to 80.7) with trastuzumab deruxtecan and 34.1% (95% CI, 27.7 to 40.5) with trastuzumab emtansine (hazard ratio for progression or death from any cause, 0.28; 95% CI, 0.22 to 0.37; P<0.001). The percentage of patients who were alive at 12 months was 94.1% (95% CI, 90.3 to 96.4) with trastuzumab deruxtecan and 85.9% (95% CI, 80.9 to 89.7) with trastuzumab emtansine (hazard ratio for death, 0.55; 95% CI, 0.36 to 0.86; prespecified significance boundary not reached). An overall response (a complete or partial response) occurred in 79.7% (95% CI, 74.3 to 84.4) of the patients who received trastuzumab deruxtecan and in 34.2% (95% CI, 28.5 to 40.3) of those who received trastuzumab emtansine. The incidence of drug-related adverse events of any grade was 98.1% with trastuzumab deruxtecan and 86.6% with trastuzumab emtansine, and the incidence of drug-related adverse events of grade 3 or 4 was 45.1% and 39.8%, respectively. Adjudicated drug-related interstitial lung disease or pneumonitis occurred in 10.5% of the patients in the trastuzumab deruxtecan group and in 1.9% of those in the trastuzumab emtansine group; none of these events were of grade 4 or 5., Conclusions: Among patients with HER2-positive metastatic breast cancer previously treated with trastuzumab and a taxane, the risk of disease progression or death was lower among those who received trastuzumab deruxtecan than among those who received trastuzumab emtansine. Treatment with trastuzumab deruxtecan was associated with interstitial lung disease and pneumonitis. (Funded by Daiichi Sankyo and AstraZeneca; DESTINY-Breast03 ClinicalTrials.gov number, NCT03529110.)., (Copyright © 2022 Massachusetts Medical Society.)