Treatment Of HER2-positive Breast Cancer Research Articles

Photothermal Depth Profiling of Gelatin-Stabilised Gold Nanorods-Trastuzumab Conjugate as a Potential Breast Cancer Photothermal Agent

AbstractGold nanorods (AuNRs) are powerful photothermal agents (PTAs) in cancer treatment due to their near-infrared laser light absorption ability. However, the cytotoxicity of AuNRs caused by the presence of cationic surfactants often used and their lack of specificity affect their application in photothermal therapy. Thus, we herein developed a bioconjugate obtained from the functionalisation of AuNRs to gelatin (Gel@AuNRs), followed by the conjugation of the as-synthesised material to a breast cancer antibody, trastuzumab (Trast-Gel@AuNRs) to address these issues. The optical and structural characterization of the as-synthesized indicated no significant changes in the optical properties of AuNRs after their functionalisation with gelatin and conjugation with the antibody. The photothermal profiling of the as-synthesised materials showed that AuNRs still have an excellent photothermal conversion efficiency (PCE) after their functionalisation (20%) and their conjugation to an antibody (19%). In addition, the In vitro photothermal depth response showed that Trast-Gel@AuNRs is a promising photothermal agent for HER2-positive breast cancer treatment. Graphical Abstract

Apple polyphenol phloretin inhibits type II glucose transporter and enhances anti-HER2 antibody drug binding as an adjuvant treatment for HER2-positive breast cancer

Apple polyphenol phloretin inhibits type II glucose transporter and enhances anti-HER2 antibody drug binding as an adjuvant treatment for HER2-positive breast cancer

In Vitro Assessment of 177Lu-Labeled Trastuzumab-Targeted Mesoporous Carbon@Silica Nanostructure for the Treatment of HER2-Positive Breast Cancer.

This study assessed the effectiveness of a trastuzumab-targeted 177Lu-labeled mesoporous Carbon@Silica nanostructure (DOTA@TRA/MC@Si) for HER2-positive breast cancer treatment, focusing on its uptake, internalization, and efflux in breast cancer cells. The synthesized PEI-MC@Si nanocomposite was reacted with DOTA-NHS-ester, confirmed by the Arsenazo(III) assay. Following this, TRA was conjugated to the DOTA@PEI-MC@Si for targeting. DOTA@PEI-MC@Si and DOTA@TRA/MC@Si nanocomposites were labeled with 177Lu, and their efficacy was evaluated through in vitro radiolabeling experiments. According to the results, the DOTA@TRA/MC@Si nanocomposite was successfully labeled with 177Lu, yielding a radiochemical yield of 93.0 ± 2.4%. In vitro studies revealed a higher uptake of the [177Lu]Lu-DOTA@TRA/MC@Si nanocomposite in HER2-positive SK-BR-3 cells (44.0 ± 4.6% after 24 h) compared to MDA-MB-231 cells (21.0 ± 2.3%). The IC50 values for TRA-dependent uptake in the SK-BR-3 and BT-474 cells were 0.9 µM and 1.3 µM, respectively, indicating affinity toward HER-2 receptor-expressing cells. The lipophilic distribution coefficients of the radiolabeled nanocomposites were determined to be 1.7 ± 0.3 for [177Lu]Lu-DOTA@TRA/MC@Si and 1.5 ± 0.2 for [177Lu]Lu-DOTA@PEI-MC@Si, suggesting sufficient passive transport through the cell membrane and increased accumulation in target tissues. The [177Lu]Lu-DOTA@TRA/MC@Si nanocomposite showed an uptake into HER2-positive cell lines, marking a valuable step toward the development of a nanoparticle-based therapeutic agent for an improved treatment strategy for HER2-positive breast cancer.

Real-World Study of Adjuvant Biosimilar Trastuzumab-dkst for HER2-Positive Breast Cancer Treatment in a Brazilian Population.

Biological monoclonal antibodies play a pivotal role in cancer treatment, with biosimilars significantly enhancing their accessibility. In Brazil's ethnically diverse setting, real-world evidence is crucial for assessing the effectiveness and applicability of these therapies in routine clinical practice. We performed a multicentric, observational, prospective real-world study on biosimilar trastuzumab-dkst for adjuvant treatment of early HER2-positive breast cancer in Brazilian patients. Data were collected using a case-report form. Of the 176 recruited, we present data from the first 59 patients (mean age 51.7 ± 12.9years) who had completed treatment with trastuzumab-dkst. The mean time from diagnosis to the first adjuvant treatment with trastuzumab-dkst was 5.5 ± 2.7months. Of the patients, 59% of patients achieved at least a 30-month follow-up. The 31.7-month invasive disease-free survival rate (IDFS) was 94.5% (95% CI 83.9-98.2%) and median IDFS was not achieved, since only three patients had invasive disease recurrence. The overall survival rate was 100% until the last assessment. The observed adverse events were similar to those presented by other studies using biosimilar or reference trastuzumab. Four serious adverse events (8.5%) were observed. A reduction in left ventricular ejection fraction of at least 10% was observed in 16.9% of participants. There was no treatment interruption, and three participants (5.1%) had their trastuzumab-dkst dose reduced. Our study reinforces the existing pivotal data, underscoring the real-world efficacy and safety of biosimilar trastuzumab-dkst in the adjuvant treatment for early HER2-positive breast cancer. The preliminary long-term effectiveness and safety data we present further validate trastuzumab-dkst's role as a cost-saving alternative in oncological care. These findings have important implications for improving patient access to crucial treatments and for the more efficient use of healthcare resources. NCT03892655.

Trastuzumab, pertuzumab and nab-paclitaxel plus pyrotinib or not in neoadjuvant treatment of HER2-positive breast cancer: A multi-center, randomized, open-label, phase II study.

e12634 Background: Trastuzumab plus pertuzumab (TP) combined with chemotherapy is the standard neoadjuvant treatment regimen for HER2+ breast cancer. Anti-HER2 tyrosine kinase inhibitor, pyrotinib, shows great efficacy in HER2+ metastatic breast cancer, but lacking efficacy data on the basis of TP and chemotherapy in the neoadjuvant setting. This study aims to evaluate the efficacy and safety of TP plus nab-paclitaxel with or without pyrotinib as neoadjuvant treatment in HER2+ breast cancer. Methods: Stage II-III HER2+ breast cancer patients, stratified by disease stage (II vs. III) and hormone receptor (HR) status (positive vs. negative), were randomized 1:1 into the pyrotinib group or the control group. Both groups received a combination of 3-weekly TP and weekly nab-paclitaxel for 12 weeks. The pyrotinib group was concurrent given 320mg pyrotinib once daily. Primary endpoint was the total pathological complete remission (tpCR), defined as no invasive cancer in the breast and axillary lymph node. Results: From Nov 2020 to Apr 2023, a total of 109 patients were enrolled, with 108 receiving treatment: 55 in the pyrotinib group and 53 in the control group.The tpCR rate was 65.5% (95% CI: 51.4%, 77.8%) in the pyrotinib group, which shows no significant difference with the control group [60.4% (95% CI: 46.0%,73.5), P = 0.585). The breast pathological complete response (bpCR) rates were 70.9% (95% CI: 57.1%,82.4%) and 64.2%(95% CI: 49.8%,76.9%) in the pyrotinib and control group, respectively (P = 0.453). In the pyrotinib group, 52 (94.5%), 31 (56.4%), and 23 (41.8%) patients experienced dose-interruption, dose-reduction, and discontinuation of pyrotinib, respectively. The most common grade ≥3 adverse events in the pyrotinib and control groups were diarrhea (58.1% vs. 0%), decreased neutrophil count (23.6% vs. 15.1%), and decreased white blood cell count (16.4% vs. 7.5%). Conclusions: Our study showed pyrotinib didn’t significantly improve tpCR rate with pyrotinib on the basis of TP and nab-paclitaxel neoadjuvant therapy of HER2+ breast cancer. Concurrent pyrotinib treatment with TP was associated with a high rate of severe diarrhea. Further biomarker analyses are needed to identify which population would receive great benefit with neoadjuvant pyrotinib therapy in HER2+ breast cancer. Clinical trial information: NCT04398914 .

Neoadjuvant pyrotinib and inetetamab in combination with chemotherapy for locally advanced HER2-positive breast cancer (NeoPICD study): A prospective, multicenter, open-label, single-arm study.

e12627 Background: Inetetamab, a novel monoclonal antibody targeting HER2, alters the Fc region amino acids, which induces ADCC stronger than trastuzumab. Pyrotinib is a small chemical inhibitor of pan-HER receptor tyrosine kinase. The globally recommended first-line neoadjuvant treatment for HER2-positive breast cancer is chemotherapy and two large-molecule monoclonal antibodies, which have unsatisfactory benefits for 50% of patients. This study aims to investigate the effectiveness and safety of targeted medicines, specifically inetetamab and pyrotinib, in conjunction with chemotherapy for patients diagnosed with locally advanced HER2-positive breast cancer. Methods: The trial was structured as a multicenter, open-label, single-arm, prospective study. 143 treatment-naive HER2-positive locally advanced breast cancer patients were planned for the trial. Eligible patients will be administered six cycles of neoadjuvant treatment, including carboplatin (AUC=6mg/mL×min, ivgtt), doxorubicin (75mg/m2, ivgtt), inetetamab (initial loading dosage of 8mg/kg, maintenance dose of 6mg/kg), and pyrotinib (400mg/day, po). The surgery was conducted after the neoadjuvant phase, subsequent to a one-year course of targeted therapy with inetetamab and pyrotinib. The primary endpoint of the study is the total pathologic complete response (tpCR). The secondary endpoints include event-free survival (EFS), disease-free survival (DFS), distant metastasis-free survival (DMFS), neurologic disease-free survival (NDFS), overall survival (OS), and safety. Results: A cohort of 70 patients was enrolled between Nov. 27, 2021 and Feb. 1, 2024. Most patients completed the six-cycle neoadjuvant therapy with inetetamab, pyrotinib, and chemotherapy. The pathological findings of 49 patients who had radical surgery revealed that 65.3% (32/49, 95% CI, 0.515-0.791) of them achieved tpCR (ypT0/Tis ypN0). The initial subgroup analysis revealed that among patients with negative hormone receptors, the rate of tpCR was 80.0% (24/30, 95% CI, 64.8-95.2). Moreover, hormone receptor was statistically determined to be an independent factor influencing the effectiveness of the new treatment regimen ( p=0.032). The prevailing grade 3 or more severe adverse events included anemia (12.8%), diarrhea (10.0%), leukopenia (4.2%), liver dysfunction (4.2%) and renal dysfunction (4.2%). As of now, no treatment-related deaths have been documented. Conclusions: The ongoing study is actively enrolling participants. Preliminary findings from the study indicate that the combination of neoadjuvant inetetamab and pyrotinib with chemotherapy has demonstrated satisfactory effectiveness and manageable side effects. This offers a promising alternative for patients with locally advanced breast cancer that is HER2-positive. Clinical trial information: NCT06234137 .

Efficacy and safety of recombinant humanized anti-HER2 antibody-MMAE conjugate (RC48) in neoadjuvant for HER2-positive breast cancer: A single-arm phase II study.

e12636 Background: Breast cancer patients who achieve pCR after neoadjuvant therapy have a relatively good prognosis. Whether antibody‐drug conjugates (ADCs) can replace traditional chemotherapy combined with dual-target therapy in neoadjuvant therapy still needs to be explored. RC48 is a novel recombinant human anti-HER2 monoclonal antibody conjugated with a microtubule inhibitor (MMAE) via a cleavable linker, which can effectively kill HER2-positive tumors as well as tumors with low or heterogeneous HER2 expression through the bystander effect. The purpose of this study was to evaluate the efficacy and safety of RC48 in neoadjuvant treatment of HER2-positive breast cancer. Methods: Patients with HER2-positive breast cancer (size>20mm) or confirmed axillary lymph node metastasis were eligible and received RC48 at a dose of 2.5mg/kg alone every 2 weeks for 6 cycles followed by surgery. EC was administered postoperatively every 21 days for 4 cycles. Trastuzumab combined with pertuzumab was administered for 1 year in the adjuvant setting. The primary endpoints were ORR and pCR rates. Results: 23 patients had been enrolled, and all of them had completed surgical treatment. The median age was 45(38-70) years. The current results showed that 13.0% (3/23) achieved pCR, 78.3% (18/23) achieved PR, and 8.7% (2/23) experienced PD. The ORR was 91.3%. 42% (5/12) of patients with initially positive axillary lymph nodes turned negative after surgery. 11.8% (2/17) HR-/HER2+ patients achieved pCR. According to the proportion of target lesion reduction, patients were divided into mild response (0-50%) and moderate-to-severe response (51%-100%). In the HR-/HER2+ subtype group, 23.5% (4/17) had a mild response, and 76.5% (13/17) had a moderate-to-severe response. 6 patients with HR+ have been enrolled, and 16.7% (1/6) of them achieved pCR. All of HR+ subtypes had a moderate-to-severe response. No relevant serious (grade 3/4) toxicity has been reported. Conclusions: The present data showed an acceptable pCR rate with RC48 in HER2-positive breast cancer. Although the pCR rate was lower than the traditional chemotherapy combined with targeted therapy, the effect of rapid reduction of tumor volume was better (the moderate-severe remission rate was 82.6%). For HR+/HER2+ breast cancer, the ORR in this study reached 100%, indicating that the novel ADC had a significant inhibitory effect on the crosstalk between ER and HER2. And it was expected that the Destiny Breast 11 study would show similar results. This scheme had a good negative conversion rate for patients with positive axillary lymph nodes. Finally, RC48 provided a neoadjuvant treatment option with low toxicity and high patient compliance for HER2-positive breast cancer. Clinical trial information: NCT05134519 .

Combined transcriptome and proteome analysis reveals MSN and ARFIP2 as biomarkers for trastuzumab resistance of breast cancer.

HER2-positive breast cancer (BC) accounts for 20-30% of all BC subtypes and is linked to poor prognosis. Trastuzumab (Tz), a humanized anti-HER2 monoclonal antibody, is a first-line treatment for HER2-positive breast cancer which faces resistance challenges. This study aimed to identify the biomarkers driving trastuzumab resistance. Differential expression analysis of genes and proteins between trastuzumab-sensitive (TS) and trastuzumab-resistant (TR) cells was conducted using RNA-seq and iTRAQ. Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) were used to study their functions. The prognostic significance and protein levels of ARFIP2 and MSN were evaluated using online tools and immunohistochemistry. Sensitivity of MSN and ARFIP2 to other therapies was assessed using public pharmacogenomics databases and the R language. Five genes were up-regulated, and nine genes were down-regulated in TR cells at both transcriptional and protein levels. Low ARFIP2 and high MSN expression linked to poor BC prognosis. MSN increased and ARFIP2 decreased in TR patients, correlating with shorter OS. MSN negatively impacted fulvestrant and immunotherapy sensitivity, while ARFIP2 had a positive impact. Our findings suggest that MSN and ARFIP2 could serve as promising biomarkers for predicting response to Tz, offering valuable insights for future research in the identification of diagnostic and therapeutic targets for BC patients with Tz resistance.

Comparison of anthracycline-containing and anthracycline-free regimens in neoadjuvant HER-2 positive breast cancer treatment

While some clinics have adopted abbreviated neoadjuvant treatment for HER2-positive breast cancer, there remains a shortage of comprehensive clinical data to support this practice. This is a retrospective, multicenter study. A total of 142 patients were included in the study who are HER2-positive breast cancer, aged ≤ 65 years, with left ventricular ejection fraction ≥ 50%, received neoadjuvant chemotherapy and underwent surgery at 10 different oncology centers in Türkiye between October 2016 and December 2022. The treatment arms were divided into 4–6 cycles of docetaxel/trastuzumab/pertuzumab for arm A, 4 cycles of adriamycin/cyclophosphamide followed by 4 cycles of taxane/TP for arm B. There were 50 patients (35.2%) in arm A and 92 patients (64.8%) in arm B. The median follow-up of all of the patients was 19.9 months (95% CI 17.5–22.3). The 3-year DFS rates for treatment arms A and B were 90.0% and 83.8%, respectively, and the survival outcomes between the groups were similar (p = 0.34). Furthermore, the pathologic complete response rates were similar in both treatment arms, at 50.0% and 51.1%, respectively (p = 0.90). This study supports shortened neoadjuvant treatment of HER2-positive breast cancer, a common practice in some clinics.

Abstract PO5-01-03: Neoadjuvant HER2-targeted regimens with or without anthracyclines for HER2-positive inflammatory breast cancer (IBC): a multicenter retrospective study

Abstract Background Previous randomized clinical trials have shown no significant benefit with the addition of anthracyclines to neoadjuvant treatment for HER2-positive breast cancer. However, these studies did not focus on inflammatory breast cancer (IBC), or a small minority of patients on these trials. The study aims to compare pathologic complete response rates with and without anthracyclines in HER2-positive IBC. Methods We reviewed patients diagnosed with Stage III HER2-positive IBC who underwent neoadjuvant therapy and modified radical mastectomy at MD Anderson Cancer Center and Dana-Farber Cancer Institute between 2014 and 2021. Patients received either docetaxel/trastuzumab/pertuzumab-doxorubicin/cyclophosphamide (THP-AC) or docetaxel/carboplatin/trastuzumab/pertuzumab (TCHP). The primary outcome was pathologic complete response (pCR) rate, defined as ypTisT0/N0. Secondary outcomes included 2-year event-free survival (EFS) and overall survival (OS). Univariate and multivariable analyses were performed with adjustments for clinically relevant covariates. Results Ninety-nine patients were included in the analysis. Thirty-nine patients received TCHP and 60 received THP-AC. The median follow-up time was 3.02 years. Three patients had disease progression during neoadjuvant therapy. pCR rates did not differ between the two regimens (48.7% TCHP vs. 51.7% THP-AC; p = 0.774). Patient’s baseline characteristics did not significantly affect the pCR rate, except for age. A multivariable logistic regression model adjusted for age and estrogen receptor (ER) status did not show a significant association between pCR and regimen (odds ratio 1.232, 95% CI 0.537–2.829 for THP-AC vs. TCHP, p = 0.623). The 2-year EFS rates for TCHP and THP-AC were 57% and 74%, respectively. In univariate analysis, patients who received THP-AC had better EFS than patients who received TCHP (hazard ratio [HR] 0.423, 95% CI 0.214–0.835, p = 0.013). The EFS benefit of THP-AC remained statistically significant after adjusting for age and type of adjuvant therapy in the final reduced multivariable Cox model (HR 0.441, 95% CI 0.220–0.882, p = 0.021). Univariate analysis did not show a significant association between EFS and other baseline covariates (body mass index, race, N and M category, nuclear grade, ER status, and HER2-targeted therapy). OS did not differ between the THP-AC and TCHP groups (HR 0.419, 95% CI 0.122–1.440, p = 0.167). Conclusions The present analysis revealed that a non–anthracycline-containing regimen in HER2-positive IBC patients had no significant difference in pCR rates but was associated with lower 2-year EFS when compared to an anthracycline-containing regimen. However, OS was similar. Limitations of the study include a small sample size, lack of temporal analysis, and retrospective design with its possible selection bias. Further investigation of the optimal neoadjuvant regimen for patients with HER2-positive IBC is warranted. Citation Format: Toshiaki Iwase, Sridhar Nithya, Megumi Kai, Jie Willey, Wenli Dong, Yu Shen, Savitri Krishnamurthy, Anthony Lucci, H. T. Carisa Le-Petross, Azadeh Nasrazadani, Sadia Saleem, Rachel Layman, Vicente Valero, Debu Tripathy, Wendy Woodward, Yee Chung Cheng, Faina Nakhlis, Jennifer Bellon, Filipa Lynce, Naoto Ueno. Neoadjuvant HER2-targeted regimens with or without anthracyclines for HER2-positive inflammatory breast cancer (IBC): a multicenter retrospective study [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO5-01-03.

Abstract PO3-08-10: Somatic mutations of a multigene panel in Chinese HER2-positive patients undergoing neoadjuvant therapy and impact on prognosis based on TP53 status:a single-institution retrospective cohort

Abstract Background: Gene mutations and copy number variations (CNVs) are associated with the occurrence and development of tumors. Neoadjuvant therapy (NAT) has shown greater clinical benefit in the treatment of HER2-positive breast cancer (BC). The impact of genetic mutations on NAT efficacy in BC has been frequently reported, but the relationship between genetic mutations and NAT efficacy and the long-term prognosis in HER2-positive BC patients still requires more high-quality studies. Methods: This retrospective cohort study was conducted patients receiving NAT between September 2017 and March 2021 in the Department of Breast Surgery of Fudan University Shanghai Cancer Center (FUSCC). The genomic characteristics of 513 cancer-related genes from the archived tumour blocks were assessed by next-generation sequencing (NGS). The relationship between tumour mutated gene and the postoperative pathological complete response (pCR) as well as prognosis of the disease-free survival (DFS) were further explored.Statistical methods included Chi-square test, fisher's exact test, Kaplan-Meier survival analysis, all of which were completed by SPSS 20.0. Results: 208(47.8%) patients achieved pCR after HER2-targeted NAT and 40(9.2%) patients encountered DFS events. The frequency of somatic alterations in TP53(60%), PIK3CA (15%) and ERBB2(11%) was highest in women with HER2-positive breast cancer. KMT2C (P= 0.036) and TP53(P=0.037) mutations were significantly increased in patients with DFS events. In the HER2+/HR- cohort, patients who achieved pCR had significantly benefit in prognosis (HR=3.605, P=0.002), and CCND1 amplifications(p=0.014), ATM(p=0.016) and GATA3(p=0.016) mutations were more frequent. ERBB2 mutations were significantly associated with younger ages of diagnosis(p=0.018). TP53 mutations were associated with worse DFS (HR=3.242, P=0.0110) as well as more DFS events(p=0.048). Furthermore, TP53 mutations had significant prognostic importance in HER2-positive BC patients with HR-negative (HR=3.712, P=0.0266), pCR (HR=6.253, P=0.0268) and who received trastuzumab-only targeted therapy (HR=4.145, P=0.0105). Conclusions: Regard to diverse hormone receptor status or neoadjuvant efficacy, the genetic mutation maps of Chinese HER2+ patients receiving NAT are disparate. Our study found that TP53 mutations have significant prognostic value in patients with NAT for HER2-positive BC and patients benefit differently depending on HR status, neoadjuvant regimens and response. Citation Format: Min Xiong, Liren Wangxu, Jingyan Xue, Benlong Yang, Jiong Wu. Somatic mutations of a multigene panel in Chinese HER2-positive patients undergoing neoadjuvant therapy and impact on prognosis based on TP53 status:a single-institution retrospective cohort [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO3-08-10.

Abstract PO3-24-04: Altered epigenetic modifications and genome architecture reshape lipid metabolism during secondary trastuzumab resistance formation of HER2-positive breast cancer

Abstract Title Altered epigenetic modifications and genome architecture reshape lipid metabolism during secondary trastuzumab resistance formation of HER2-positive breast cancer Background Secondary trastuzumab resistance seriously affects the treatment of HER2-positive breast cancer. Although studies have demonstrated several key cellular properties that are closely accompanied with trastuzumab resistance formation, we still have poor knowledge on the genetic and epigenetic variations that promote such transformation. Here we suggested that the epigenetic modification changes on histone H3 together with altered chromatin architecture promote lipid metabolism reprogramming during secondary trastuzumab formation. Materials and methods Induced secondary trastuzumab-resistant SKBR3_HR cell line together with the original trastuzumab-sensitive SKBR3 cell line were applied in this study. Total RNA was collected for transcriptome analysis. Anti-H3K4me3 and K27me3 antibodies were chosen for CUT&Tag sequencing library preparation. Total genome DNA was prepared for Micro-C sequencing library preparation. Activity score of metabolism pathway was calculated as relative gene expression value averaged over all genes in this pathway in certain cell types. Results Upregulation of arachidonic acid metabolism and downregulation of unsaturated fatty acid synthesis, which are mainly characterized by the activation of PTGS1 and PTGES genes and the repression of FASN and SCD genes, respectively, were observed during the formation of secondary trastuzumab resistance from SKBR3 cell to SKBR3_HR cells. Variations of H3k4me3 instead of H3k27me3 regulate the expression of these 4 genes. The accumulation of H3k4me3 was detected at the promoters of PTGS1 and PTGES genes while they were removed from the promoters of FASN and SCD genes in SKBR3_HR cells. More intra-chromosomal interactions were constituted during resistance formation. In detail, 4626 and 4394 topological associated domains, 3125 and 5824 DNA loops were founded in SKBR3 and SKBR3_HR cells, respectively. Furthermore, the lost and gained DNA loops between SCD and PTGS1 genes and distant genome regions may indicate the weaken and strengthen interactions with transcriptional regulators located there. Conclusions During trastuzumab resistance formation, altered histone modifications as well as higher genome structure could regulate the expression of key genes in lipid metabolism pathways, which may further affect cell properties and interactions with cells in tumor microenvironment. Citation Format: Ningjun Duan, Yijia Hua, Yongmei Yin. Altered epigenetic modifications and genome architecture reshape lipid metabolism during secondary trastuzumab resistance formation of HER2-positive breast cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO3-24-04.

Abstract PO2-07-06: Multimodal learning predictor of HER2-positive breast cancer therapy response in the randomized PREDIX HER2 trial

Abstract Background: The PREDIX HER2 trial, compared six courses of docetaxel, trastuzumab, and pertuzumab (DTP) vs. trastuzumab emtansine (T-DM1) as neoadjuvant treatment for HER2-positive breast cancer (BC). Similar rates of pathologic complete response (pCR) were seen. Methods: Clinicopathological, shallow whole-genome sequencing (CUTseq, n=176), whole exome sequencing (WES, n=192), and RNA-sequencing (RNA-seq, n=187) data were generated using fresh-frozen baseline core biopsies. Potential tumor intrinsic resistance factors and microenvironment components were quantified by multi-omics analysis, including BC-specific somatic mutations and copy number alterations (CNA), COSMIC mutational signatures, CNA-based chromosomal instability signatures (CIN), subclone percentage, PAM50 subtype, GGI/PIK3CA score, HER2DX score, immune profiles (Danaher signature score, TIDE score and immune repertoires). We assessed the association of biomarkers with pCR in each treatment arm using logistic regression adjusting for hormone receptor (HR) status, and evaluated their predictive value by adding the interaction term (biomarker x treatment arm). In addition, a machine learning (ML) analysis was conducted from different classifiers, comprising unimodal ML-based models from clinical, RNA and DNA information, respectively. Model performance was assessed using the mean and standard deviation (mean ± std) of the area under receiver operator characteristic curve (AUC), positive predictive value (PPV) and negative predictive value (NPV) using a nested stratified cross-validation (CV) schema of 200 outer shuffle splits and 100 inner 5-fold CV to mitigate potential risk of overfitting. Results: In DTP arm, patients with higher ERBB2 copy ratio (ORadj=1.98, p=0.004) or mRNA (ORadj=3.08, p< 0.001) or HER2-enriched subtype (PAM50) (ORadj=1.78, p=0.02) had higher pCR rates, while ESR1 gene expression (ORadj=0.59, p=0.07) predicted treatment resistance despite adjustment for HR status. Conversely, response to T-DM1 was less likely to depend on ERBB2 profiles and only PAM50 HER2 enriched subtype (ORadj=1.53, p=0.1) showed higher pCR rate (52% vs. 25%) than other subtypes. Both ESR1 (ORadj=0.4, p=0.008) and PGR (ORadj=0.5, p=0.03) gene expression were independent predictors of T-DM1 resistance. Pre-treatment immune exclusion metrics could predict resistance to DTP (endothelial cell, ORadj=0.67, p=0.07) and T-DM1 (neutrophils, ORadj=0.54, p=0.02; mast cells, ORadj=0.57, p=0.02; cancer-associated fibroblasts, ORadj=0.67, p=0.09)), respectively. Predefined metrics such as PIK3CA signature score (ORadj =1.67, p=0.04) and Taxane response score (ORadj =1.64, p=0.03) were positively related to pCR in DTP arm. Genome instability, involving CIN CX2 signature (impaired homologous recombination) (ORadj=1.71, p=0.05), COSMIC signature6 (ORadj =1.53, p=0.07) and signature13 (ORadj =1.57, p=0.05), predicted benefit from DTP. The biomarker-treatment interaction tests were significant for HER2DX (pinteraction=0.004) and COSMIC signature15 (defective DNA mismatch repair) (pinteraction=0.007): lower HERDX score (ORadj =0.73, p=0.14) or higher COSMIC signature15 score (ORadj =1.51, p=0.1) could identify patients benefiting from T-DM1, while being resistant to DTP (HERDX: ORadj =1.46, p=0.13; signature15: ORadj =0.70, p=0.1). In the ML models, clinical information yielded an AUC=0.62±0.07, PPV=0.64±0.12 and NPV=0.64±0.06; for DNA data, AUC was equal to 0.70±0.08, PPV=0.72±0.09 and NPV=0.71±0.07; an adaptive boosting ensemble learning on RNA reported slightly increased pCR prediction performance (AUC=0.72±0.06, PPV=0.64±0.06, NPV=0.80±0.09). Conclusion: This study demonstrates that antibody–drug conjugates and standard treatment harbor strikingly distinctive biomarkers across tumor ecosystem. Further external validation and integrated ML model comprising all unimodal models are ongoing. Citation Format: Kang Wang, Yajing Zhu, Ioannis Zerdes, Emmanouil Sifakis, Georgios Manikis, Dimitrios Salgkamis, Nikolaos Tsiknakis, Luuk Harbers, Nicola Crosetto, Jonas Bergh, Alexios Matikas, Thomas Hatschek, Theodoros Foukakis. Multimodal learning predictor of HER2-positive breast cancer therapy response in the randomized PREDIX HER2 trial [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO2-07-06.

Effects of neratinib on angiogenesis and the early stage of the embryo using chicken embryo as a model.

Angiogenesis is the process of forming new blood capillaries from pre-existing vessels. Even though it is essential during normal development, it plays a major role in cancer progression. Neratinib is a pan-human epidermal growth factor receptor (HER) inhibitor that has recently been approved for the treatment of HER2-positive breast cancer. However, its effects on angiogenesis and embryogenesis remain unknown. This study examined the antiangiogenic effects of neratinib using the chorioallantoic membrane (CAM) of chicken embryos. We also evaluated neratinib's toxicity during the early stages of normal development using the chicken embryos, primary embryonic fibroblasts (EFBs), and human umbilical vein endothelial cells (HUVEC). Our findings revealed that neratinib significantly inhibited the CAM angiogenesis compared to controls by reducing vessel percentage area and the average vessel length. Furthermore, neratinib downregulated vascular endothelial growth factor (VEGF), a key mediator of angiogenesis. At lower concentrations, neratinib was well-tolerated during early stages of normal development. Additionally, EFBs treated with neratinib showed no morphological or viability changes when compared to controls. However, at the highest concentration tested, neratinib treatment reduced HUVEC cell viability. This effect may be associated with the dysregulation of key apoptotic genes, including caspase-3, caspase-8, caspase-9, and the B-cell lymphoma 2 (Bcl2) gene. Our findings indicate a novel potential application of neratinib as an antiangiogenic agent, exhibiting tolerable toxicity in the early stages of embryogenesis.

Abstract PO1-17-03: Real-world evidence of Trastuzumab biosimilars in HER2-positive breast cancer: Evaluating utilization, efficacy, and safety in Taiwan

Abstract Purpose Biosimilars have emerged as a promising alternative to reference biologic products for the treatment of cancers and immunological diseases. With regard to breast cancer, trastuzumab, a reference monoclonal antibody biologic, has been the standard of care for early and advanced HER2-positive breast cancer since 1998. Trastuzumab biosimilars, which provide comparable efficacy at a lower cost, have the potential to reduce financial burden on patients and healthcare systems and improve patient access to HER2-targeted therapy. This study aimed to evaluate the utilization, efficacy, and safety of trastuzumab biosimilars in HER2-positive breast cancer patients at Kaohsiung Veterans General Hospital. Methods A total of 113 HER2-positive breast cancer patients were enrolled between February 2020 and December 2022 and treated with trastuzumab biosimilars (OGIVRI®, trastuzumab-dkst). Of these, 44 were in the neoadjuvant group, 27 in the adjuvant group, and 42 in the metastatic group. Clinical outcomes were evaluated, including pathological complete response (pCR) rate in the neoadjuvant group, objective response rate (ORR) and clinical benefit rate (CBR) in the metastatic group, and safety profile in all groups. Results In the neoadjuvant group, 18 out of 44 evaluable patients achieved pathological complete response after surgery, resulting in a pCR rate of 40.90%. In the metastatic group , the ORR was 57.14% and the CBR was 90.47%. Furthermore, in the metastatic group, treatment with dual blockade using biosimilars resulted in an better ORR of 62.96%. No adverse events of cardiac toxicity were reported in any group. In the adjuvant group, longer follow-up is needed to assess efficacy. Conclusions Our real-world experience suggests that trastuzumab biosimilars are a safe and cost-effective alternative to reference trastuzumab in the treatment of HER2-positive breast cancer. Biosimilar trastuzumab demonstrated efficacy in the neoadjuvant setting, while dual blockade with biosimilars resulted in better disease control in the metastatic setting. Further follow-up is necessary to evaluate the efficacy of trastuzumab biosimilars in the adjuvant setting. Citation Format: Yi-Hung Lo, Yen-Dun Tzeng. Real-world evidence of Trastuzumab biosimilars in HER2-positive breast cancer: Evaluating utilization, efficacy, and safety in Taiwan [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO1-17-03.

Abstract PO2-12-07: Risk of anaphylaxis associated with the use of pertuzumab or other biologics with potential for use outside the hospital

Abstract BACKGROUND Intravenous (IV) pertuzumab (P) and trastuzumab (H) are approved in the US for the treatment of HER2-positive breast cancer. P and H are also approved as a fixed-dose combination for SC injection (pertuzumab, trastuzumab, and hyaluronidase-zzxf; PH FDC SC). PH FDC SC may offer the possibility of treatment outside a hospital setting by a healthcare professional. Anaphylactic reactions can be a concern with the use of biologics. PH is also frequently initiated with six to eight cycles of taxanes, which can also be associated with anaphylaxis. We used administrative claims data to evaluate the risk of anaphylaxis associated with the real-world administration of PH or other biologic drugs in the real world. Our objective was to evaluate the risk of anaphylaxis associated with the administration of P and to contextualize the risk estimate by using other biologics that can be used outside the hospital as a benchmark. METHODS Cohorts of incident users were selected using retrospective records from a US healthcare claims database (IQVIA). Patients included were privately insured in the US, aged 16 to 65 years, and initiated a treatment of interest between 2012 and 2021. Possible and severe anaphylactic events (PAEs) were identified using the algorithm developed by the US Food and Drug Administration (FDA) Sentinel Initiative and updated with ICD10 codes (PMID: 34181291). PAEs were attributed to a drug if it occurred on the day of administration or the day after. The prevalence proportion (PP) of PAE was used to approximate the risk of anaphylaxis at each cycle. A sensitivity analysis using the proportion of prior P use amongst the cases of PAE beyond cycle 1 in the H cohort was conducted to approximate how many cases of PAE could have been missed at cycle 1 of P due to a depletion of susceptibles (as P IV and H may be administered sequentially in any order, patients with a PAE from H would not receive scheduled P and thus be excluded from the P cohort). RESULTS A total of 1,919,748 patients constituted 27 cohorts. Of them, 184,414 patients initiated monoclonal antibodies (mAbs) in 12 cohorts of which 12,264 and 184 initiated P IV and PH FDC SC, respectively. In the P IV cohort, seven PAE events were observed up to cycle 6 and none after. The PP at cycle 1 of P was 1.63 per 10,000 patients (95% confidence interval [CI] = 0.45, 5.94). The risk was comparable to that of other mAbs where anaphylaxis risk is described as uncommon/rare (Table). Accounting for a potential depletion of susceptibles increased the PP at cycle 1 of P to 2.45/10,000 (95% CI = 0.83, 7.19). No PAEs were reported in patients treated with PH FDC SC. CONCLUSIONS Using one of the largest datasets available, results suggest the risk of PAE with P administration could be within the range of what is observed with other mAbs that can be administered outside of the hospital. All events were observed when patients are expected to receive treatment at the hospital due to taxane administration. No PAE events were identified for PH FDC SC, but there were few patients in this cohort. Efforts are ongoing to identify a larger cohort treated with PH FDC SC. Risk of anaphylaxis by mAb * According to summary of product characteristics. † ≥1/1,000 to <1/100. ‡ ≥1/10,000 to <1/1,000. CI = confidence interval; H = trastuzumab; IV = intravenous; P = pertuzumab; PH FDC SC = pertuzumab, trastuzumab, and hyaluronidase-zzxf. Citation Format: Thibaut Sanglier, Tom Chambers, Joanna Harton, Laurentia Wahyudi, Magali Genevray, Eleonora Restuccia, Cécile Droz-Perroteau, Chau Dang. Risk of anaphylaxis associated with the use of pertuzumab or other biologics with potential for use outside the hospital [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO2-12-07.

Abstract PO5-01-05: An Open-label, Single-center Study Assessing the Efficacy of PH-based Regimen as Neoadjuvant Therapy for HER2-positive Early-stage Breast Cancer: Integrating Genomic Features and Functional Imaging

Abstract Background: Pathological complete response (pCR) has been demonstrated as a surrogate endpoint for disease-free and overall survival in HER2-positive early-stage breast cancer (EBC). Trastuzumab (H) plus pertuzumab (P) improved pCR rates in patients with HER2-positive early-stage breast cancer. Nevertheless, biomarkers to assess the effectiveness of this treatment in the neoadjuvant setting are still unclear. This study aims to evaluate the effectiveness of fluorodeoxyglucose positron emission tomography (18F-FDG-PET) and 68 Ga-Affibody HER2 Imaging PET (HER2-PET) in HER2 EBC neoadjuvant therapy, and to identify novel biomarkers for this regimen. Methods: HER2-positive EBC patients were prospectively recruited at Fudan University Shanghai Cancer Center between April 2020 and March 2022. All patients received the 1 dose of HP, followed by 6 cycles of docetaxel (T), carboplatin (Cb), and HP. We use FoundationOne to evaluate the genomic alterations before treatment. In addition, 18F-FDG-PET and HER2 PET were performed at baseline, after 1 cycle of HP, and after 6 cycles of TCbHP, to assess the effectiveness of these examinations in the prediction of pCR and correlation to disease burden. All patients were received surgery and completed 1 year of HP-based regimen in the adjuvant setting. Results: A total of 61 patients with a median age of 49 years were included. Among them, 93.5% of patients are node positive. 75.8% of the patients reported adverse events (AEs), primarily grade 1 and 2. The incidence of serious AEs was 6.6%. Patients exhibiting a greater than 40% reduction in SUVmax of 18-FDG-PET or HER2-PET scans from baseline to the fifth day after the initial HP treatment were classified as the treatment-sensitive group. The pCR rate for the 18-FDG-PET-sensitive group was 79.3%, while for the insensitive group was 48.1%. For HER2-PET scans, the pCR rate was 70.0% in the sensitive group and 59.3% in the non-sensitive group. To evaluate the potential biomarkers, 25 patients (13 pCR and 12 non-pCR) were evaluated with FoundationOne, with the identification of 1,321 somatic alterations. The most frequently altered genes were ERBB2 (100%), TP53 (96%), CDK12 (76%), MYC (56%), CCND1 (44%), PIK3CA (40%), and SRSF2 (36%). In the pCR group, we found PPM1D (38.5%) and RAD21 (38.5%) were altered more frequently than the non-pCR group. PIK3CA alterations were significantly reduced in pCR group, only 23% of cases are affected compared to 58.3% in non-pCR group. Patients were non-pCR had more MDM4 (41.7%) and ZNF217 (41.7%) alterations than pCR patients. Conclusion: The SUVmax value of 18-FDG-PET and HER2-PET scans are correlated well with the tumor burden and the residual disease in the HER2 EBCs. The reduction of SUVmax could predict pCR but need further exploration. Patients with alterations in PPM1D and RAD21 have a favorable response to the TCbHP regimen. Conversely, alterations in PIK3CA, MDM4, and ZNF217 are associated with treatment resistance. These results indicate the significance of 18-FDG-PET and HER2-PET in monitoring treatment effectiveness. The biomarker analysis in this study will help us understand the mechanism of HER2 positive breast cancer treatment resistance and assisting in tailoring personalized therapy. Clinical trial information: NCT04281641. Citation Format: Ming Chen, Benlong Yang, Sun Yuyun, Linxiaoxi Ma, Song Shaoli, Min He, Zhi-Ming Shao, Bingqiu Xiu, Jiong Wu. An Open-label, Single-center Study Assessing the Efficacy of PH-based Regimen as Neoadjuvant Therapy for HER2-positive Early-stage Breast Cancer: Integrating Genomic Features and Functional Imaging [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO5-01-05.

Abstract PO3-24-05: Cysteine metabolism related ferroptosis sensitivity in trastuzumab resistant HER2 positive breast cancer

Abstract Background Trastuzumab has shown great effectiveness in HER2 positive breast cancer treatment, but about 50% patients would undergo resistance during or after treatment. Although previous research has suggested several potential reasons for trastuzumab resistance, the metabolic reprogramming during resistance formation remains largely unclear. Here we identified aberrant ferroptosis associated cysteine metabolism in trastuzumab resistant HER2 positive breast cancer, which might become a novel target for overcoming resistance. Methods Trastuzumab sensitive HER2 positive breast cancer cell SKBR3 and resistant JITM1 were obtained for transcriptomics, proteomics, metabolomics and epigenomics analysis. Gene silencing was mediated by siRNAs. CUT&Tag was applied to compare H3K4me3 and H3K27me3 binding regions. DNA methylation levels and different methylated regions were evaluated by WGBS-seq. CRISPRi with dCas9-DNMT3A was applied to regulate specific DNA methylation in CpG islands. Lipid ROS was measured by flow cytometry with BODIPY-C11. Results Joint analyses of transcriptomics and proteomics according to ferroptosis pathways revealed downregulated glutathione metabolism, glutamate transmembrane and homocysteine metabolism processes, as well as upregulated fatty acid metabolism and iron metabolism pathways in JIMT1. Metabolomics verified that JIMT1 increased cysteine metabolism and decreased glutathione metabolism. SLC7A11 expression and GSH/GSSG ratio were increased in JIMT1, while no difference was observed in free cysteine. JIMT1 featured significant higher UGC codon usage bias and increased cysteinyl-tRNA synthetase. The abundance of H3K4me3 other than H3K27me3 in SLC7A11 promoter region was found increased in JIMT1, and the 5-mC level of CpG islands in SLC7A11 promoter region was shown decreased. Using dCas9-DNMT3A, the methylation of SLC7A11 promoter was enhanced and SLC7A11 expression was reduced in JIMT1. Inhibition of SLC7A11 by siRNAs, CRISPRi or Erastin all indicated a higher ferroptosis sensitivity in JIMT1. Conclusion Trastuzumab resistant HER2 positive breast cancer features aberrant cysteine metabolism resulting from altered H3K4me3 modification and DNA methylation in SLC7A11 promoter region. This might provide novel targets for further anti-HER2 treatment. Citation Format: Yongmei Yin, Yijia Hua, Ningjun Duan, Chunxiao Sun, Fan Yang. Cysteine metabolism related ferroptosis sensitivity in trastuzumab resistant HER2 positive breast cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO3-24-05.

Targeting Cardiomyocytes with Adeno Associated Viruses to Protect Hearts from Trastuzumab-induced Cardiotoxicity

Amplification of HER2 occurs in 20% of breast cancers. HER2 (known as ErbB2 in mouse) belongs to the Epidermal Growth Factor Receptor (EGFR) family that is responsible for cell growth and survival. While HER2 does not bind ligands, it forms heterodimers with HER1 (also known as EGFR) in the presence of its ligand EGF, and HER4 following stimulation with Neuregulin. In HER2-positive breast cancer where HER2 expression is high, HER2 homodimerizes leading to excessive activation of downstream signalling and cell proliferation. Current HER2-positive breast cancer treatment involves chemotherapy with drugs called anthracyclines, such as Doxorubicin, and an antibody targeting HER2 called Trastuzumab. This combination is effective in killing HER2-positive breast tumours, however, Trastuzumab alone or in combination with anthracyclines leads to severe cardiotoxicity and heart failure in 2.6-11% of cases, making it a dose-limiting side effect. We hypothesise that cardiac toxicity can be mitigated by targeting cardiomyocytes exclusively to express a mutated (but functional) version of HER2 that is not recognised by trastuzumab. We designed 3 HER2 variants wherein the trastuzumab binding domain was mutated to disrupt binding. These HER2 mutants were transfected into HEK293T cells, and we confirmed that all 3 successfully localised to the cell membrane, and did not bind trastuzumab. We have used bioluminescence resonance energy transfer to examine the capacity of all 3 mutants to activate recruitment of Grb2 to the HER2 as part of HER1/HER2 and HER4/HER2 heterodimers; Western blotting also confirming mutants were capable of stimulating ERK and Akt phosphorylation. Future studies will evaluate the effcacy of using AAVs to instruct cardiomyocytes to express these HER2 mutants in a murine model of breast cancer. We predict that this new therapy would not only mitigate cardiac toxicity, but would also permit higher doses of trastuzumab to be used to treat breast cancer. This work is supported by Australia's National Health and Medical Research Council and the Australian Research Council. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Maitake Beta-Glucan Enhances the Therapeutic Effect of Trastuzumab via Antibody-Dependent Cellular Cytotoxicity and Complement-Dependent Cytotoxicity.

Trastuzumab, an anti-HER2 monoclonal antibody, is the mainstay treatment for of HER2-positive breast cancer. However, trastuzumab resistance is often observed during treatment. Therefore, new therapeutic strategies are needed to enhance the clinical benefits of trastuzumab. Maitake β-glucan MD-Fraction, isolated from Grifola frondosa, inhibits tumor growth by enhancing immune responses. In this study, we examined the effect of MD-Fraction on trastuzumab treatment of HER2-positive breast cancer. MD-Fraction did not directly inhibit the survival of HER2-positive breast cancer cells, alone or in the presence of trastuzumab in vitro. In HER2-positive xenograft models, the combination of MD-Fraction and trastuzumab was more effective than trastuzumab alone. Peripheral blood lymphocytes and splenic natural killer cells isolated from BALB/c nu/nu mice treated with MD-Fraction showed enhanced trastuzumab-induced antibody-dependent cellular cytotoxicity (ADCC) ex vivo. MD-Fraction-treated macrophages and neutrophils did not show enhanced trastuzumab cytotoxicity in the presence of heat-inactivated serum, but they showed enhanced cytotoxicity in the presence of native serum. These results suggest that MD-Fraction-treated macrophages and neutrophils enhance trastuzumab-induced complement-dependent cellular cytotoxicity (CDCC). Treatment of HER2-positive breast cancer cells with MD-Fraction in the presence of trastuzumab and native serum increased C3a release and tumor cell lysis in a dose-dependent manner, indicating that MD-Fraction enhanced trastuzumab-induced complement-dependent cytotoxicity (CDC) by activating the complement system. This study demonstrates that the combination of trastuzumab and MD-Fraction exerts a greater antitumor effect than trastuzumab alone by enhancing ADCC, CDCC, and CDC in HER2-positive breast cancer.