Genomic Alterations Correlated to Trastuzumab Resistance and Clinical Outcomes in HER2+/HR- Breast Cancers of Patients Living in Northwestern China.

Anti-HER2 therapy has significantly improved the survival rates of patients with HER2+ breast cancer. However, a subset of these patients eventually experience treatment failure, and the underlying genetic mechanisms remain largely unexplored. This underscores the need to investigate the genomic heterogeneity of HER2+ breast cancer. In this study, we focus on HER2+/HR- breast cancer, as it differs from HER2+/HR+ breast cancer in terms of genetic and biological characteristics. We performed gene-targeted genome sequencing on 45 HER2+/HR- breast cancer samples and identified 650 mutations across 268 cancer-related genes. TP53 (71.1%) and PIK3CA (35.6%) were the most frequently mutated genes in our sample. Additionally, ERBB2 (77.8%), CDK12 (42.2%), and MYC (11.1%) exhibited a high frequency of copy number amplifications (CNAs). Comparative analysis with two other HER2+/HR- breast cancer cohorts revealed that our cohort had higher genetic variation rates in ARID1A, PKHD1, PTPN13, FANCA, SETD2, BRCA2, BLM, STAG2, FAT1, TOP2A, POLE, ATM, KMT2B, FGFR4, and EPAS1. Notably, in our cohort, NF1 and ATM mutations were more prevalent in trastuzumab-resistant patients (NF1, p=0.016; ATM, p=0.006) and were associated with primary trastuzumab resistance (NF1, p=0.042; ATM, p=0.021). Moreover, patients with NF1 mutations (p=0.009) and high histological grades (p=0.028) were more likely to experience early relapse. Ultimately, we identified a unique cancer-related gene mutation profile and a subset of genes associated with primary resistance to trastuzumab and RFS in patients with HER2+/HR- breast cancer in Northwest China. These findings could lay the groundwork for future studies aimed at elucidating the mechanisms of resistance to trastuzumab and improving HER2-targeted treatment strategies.

A high hydrophobic moment arginine-rich peptide screened by a machine learning algorithm enhanced ADC antitumor activity.

Cell-penetrating peptides (CPPs) with better biomolecule delivery properties will expand their clinical applications. Using the MLCPP2.0 machine algorithm, we screened multiple candidate sequences with potential cellular uptake ability from the nuclear localization signal/nuclear export signal database and verified them through cell-penetrating fluorescent tracing experiments. A peptide (NCR) derived from the Rev protein of the caprine arthritis-encephalitis virus exhibited efficient cell-penetrating activity, delivering over four times more EGFP than the classical CPP TAT, allowing it to accumulate in lysosomes. Structural and property analysis revealed that a high hydrophobic moment and an appropriate hydrophobic region contribute to the high delivery activity of NCR. Trastuzumab emtansine (T-DM1), a HER2-targeted antibody-drug conjugate, could improve its anti-tumor activity by enhancing targeted delivery efficiency and increasing lysosomal drug delivery. This study designed a new NCR vector to non-covalently bind T-DM1 by fusing domain Z, which can specifically bind to the Fc region of immunoglobulin G and effectively deliver T-DM1 to lysosomes. MTT results showed that the domain Z-NCR vector significantly enhanced the cytotoxicity of T-DM1 against HER2-positive tumor cells while maintaining drug specificity. Our results make a useful attempt to explore the potential application of CPP as a lysosome-targeted delivery tool.

Dual targeting non-overlapping epitopes in HER2 domain IV substantially enhanced HER2/HER2 homodimers and HER2/EGFR heterodimers internalization leading to potent antitumor activity in HER2-positive human gastric cancer.

BACKGROUND: Trastuzumab and pertuzumab combination has been approved for the treatment of patients with HER2-positive metastatic breast cancer. However, trastuzumab and pertuzumab combination did not show improvement in overall survival in patients with HER2-positive metastatic gastric cancer. METHODS: We developed a new HER2-targeted monoclonal antibody, HLX22, targeting HER2 subdomain IV as trastuzumab but with non-overlapping epitopes. We examined the antitumor effects of this novel HER2-antibody in gastric cell lines and cell line-derived xenograft (CDX) and patient-derived xenograft (PDX) models. RESULTS: HLX22 in combination with HLX02 (trastuzumab biosimilar) induced enhancement of HER2/HER2 homodimers and HER2/EGFR heterodimers internalization, which ultimately led to the reduction in signal transductions involving STAT3, P70 S6, and AKT; gene expressions of FGF-FGFR-PI3K-MTOR, EGF-EGFR-RAS, TGF-ß-SMAD, PLCG and cell cycle progression related pathways that favor tumor development, proliferation, progression, migration and survival in gastric cancer cell line NCI-N87 were also reduced. These differing but complementary actions contributed to the synergistic antitumor efficacy of the HLX22 and HLX02 combination in gastric cancer cell lines, CDX and PDX. In addition, HLX22 in combination with HLX02 demonstrated stronger antitumor efficacy than HLX02 and HLX11 (a potential pertuzumab biosimilar) combination treatment both in vitro and in vivo. CONCLUSIONS: These results suggested that the application of non-competing antibodies HLX22 and HLX02 targeting HER2 subdomain IV together may be of substantial benefit to gastric cancer patients who currently respond suboptimal to trastuzumab therapy.

Mechanisms of resistance to trastuzumab in HER2-positive gastric cancer.

Gastric cancer is one of the most prevalent cancers worldwide, and human epidermal growth factor receptor 2 (HER2)-positive cases account for approximately 20% of the total cases. Currently, trastuzumab + chemotherapy is the recommended first-line treatment for patients with HER2-positive advanced gastric cancer, and the combination has exhibited definite efficacy in HER2-targeted therapy. However, the emergence of drug resistance during treatment considerably reduces its effectiveness; thus, it is imperative to investigate the potential mechanisms underlying resistance. In the present review article, we comprehensively introduce multiple mechanisms underlying resistance to trastuzumab in HER2-positive gastric cancer cases, aiming to provide insights for rectifying issues associated with resistance to trastuzumab and devising subsequent treatment strategies.

Proteomic Characterization of a 3D HER2+ Breast Cancer Model Reveals the Role of Mitochondrial Complex I in Acquired Resistance to Trastuzumab.

HER2-targeted therapies, such as Trastuzumab (Tz), have significantly improved the clinical outcomes for patients with HER2+ breast cancer (BC). However, treatment resistance remains a major obstacle. To elucidate functional and metabolic changes associated with acquired resistance, we characterized protein profiles of BC Tz-responder spheroids (RSs) and non-responder spheroids (nRSs) by a proteomic approach. Three-dimensional cultures were generated from the HER2+ human mammary adenocarcinoma cell line BT-474 and a derived resistant cell line. Before and after a 15-day Tz treatment, samples of each condition were collected and analyzed by liquid chromatography-mass spectrometry. The analysis of differentially expressed proteins exhibited the deregulation of energetic metabolism and mitochondrial pathways. A down-regulation of carbohydrate metabolism and up-regulation of mitochondria organization proteins, the tricarboxylic acid cycle, and oxidative phosphorylation, were observed in nRSs. Of note, Complex I-related proteins were increased in this condition and the inhibition by metformin highlighted that their activity is necessary for nRS survival. Furthermore, a correlation analysis showed that overexpression of Complex I proteins NDUFA10 and NDUFS2 was associated with high clinical risk and worse survival for HER2+ BC patients. In conclusion, the non-responder phenotype identified here provides a signature of proteins and related pathways that could lead to therapeutic biomarker investigation.

Define Critical Parameters of Trastuzumab-Mediated ADCC Assays via Assay Optimization Processes, Focusing on the Impact of Cryopreserved Effector Cells on Assay Performance.

The mechanisms of mAb-induced ADCC have been well established. However, the ADCC bioassays used to quantify mAb-induced ADCC require continued development/refinement to properly assess and compare the potency of newly developed therapeutic mAbs and biosimilars to meet regulatory requirements. We used trastuzumab and a lactate dehydrogenase (LDH)-based ADCC bioassay as a model to define critical parameters of the ADCC bioassay, describing how several bioassay parameters, including preparation of effector cells, E/T ratio, target cell selection, bioassay media components, and treatment time can influence the data quality of the ADCC activity. We confirm that a 4 to 24 h recovery cultivation is required to restore peripheral blood mononuclear cells (PBMCs) and natural killer (NK) cell activity toward ADCC when using cryopreserved PBMCs. Furthermore, we delineated the cellular mechanisms underlying the restored ADCC activity following the recovery cultivation. We observed that CD69, an early marker of NK cell activation, was upregulated and a new subset CD56dim/CD16dim population was dramatically increased in the recovered NK cells, which led to an increase in expression and secretion of perforin, granzyme B, and cytokine production. This study provides comprehensive technical insights into ADCC bioassay optimization to inform trastuzumab biosimilar development. The knowledge gained from this study can also be leveraged to guide bioassay development for therapeutic mAbs with ADCC as the primary mechanism of action.

A randomized phase III double-blind placebo-controlled trial of first-line chemotherapy and trastuzumab with or without bevacizumab for patients with HER2/neu-positive metastatic breast cancer: a trial of the ECOG-ACRIN Cancer Research Group (E1105).

BACKGROUND: In 2008, bevacizumab received accelerated Food and Drug Administration (FDA) approval for use in human epidermal growth factor receptor 2 (HER2)-negative metastatic breast cancer (MBC). Based on the pre-clinical and preliminary clinical activity of the trastuzumab and bevacizumab combination, ECOG-ACRIN E1105 trial was developed to determine if the addition of bevacizumab to a chemotherapy and trastuzumab combination for first-line therapy would improve progression-free survival (PFS) in patients with HER2-positive MBC. FINDINGS: 96 patients were randomized to receive standard first-line chemotherapy and trastuzumab with or without bevacizumab between November 2007 and October 2009, and 93 began protocol therapy. Induction therapy was given for 24 weeks, followed by maintenance trastuzumab with or without bevacizumab. 60% (56/93) began carboplatin and 74% (69/93) completed 6 cycles of induction therapy. Primary endpoint was PFS. Median PFS was 11.1 and 13.8 months for placebo and bevacizumab arms, respectively (hazard ratio [HR] 95%, Confidence Interval [Cl] for bevacizumab vs. placebo: 0.73 [0.43-1.23], p = 0.24), and at a median follow-up of 70.7 months, median survival was 49.1 and 63 months (HR [95% Cl] for OS: 1.09 [0.61-1.97], p = 0.75). The most common toxicities across both arms were neutropenia and hypertension, with left ventricular systolic dysfunction, fatigue, and sensory neuropathy reported more frequently with bevacizumab. CONCLUSIONS: In this trial, the addition of bevacizumab did not improve outcomes in patients with metastatic HER2-positive breast cancer. Although the trial was underpowered due to smaller than anticipated sample size, these findings corroborated other clinical trials during this time. CLINICAL TRIAL INFORMATION: NCT00520975.

Partial response to trastuzumab deruxtecan (DS8201) following progression in HER2-amplified breast cancer with pulmonary metastases managed with disitamab vedotin (RC48): a comprehensive case report and literature review.

Breast cancer remains one of the predominant malignancies worldwide. In the context of inoperable advanced or metastatic human epidermal growth factor receptor 2 (HER2)-positive breast cancer, systemic management primarily relies on HER2-targeting monoclonal antibodies. With the successful development of anti-HER2 antibody-drug conjugates (ADCs), these agents have been increasingly integrated into therapeutic regimens for metastatic breast cancer. Here, we present the case of a 42-year-old female patient with HER2-positive pulmonary metastatic breast cancer who underwent an extensive treatment protocol. This protocol included chemotherapy, radiation therapy, hormonal therapy, surgical intervention on the breast, and anti-HER2 therapies. The anti-HER2 therapies involved both singular and dual targeting strategies using trastuzumab and the ADC disitamab vedotin (RC48) over an 8-year period. After experiencing disease progression following HER2-targeted therapy with RC48, the patient achieved noticeable partial remission through a therapeutic regimen that combined trastuzumab deruxtecan (DS8201) and tislelizumab. The data suggest a promising role for DS8201 in managing advanced stages of HER2-amplified metastatic breast cancer, especially in cases that demonstrate progression after initial HER2-directed therapies using ADCs. Furthermore, its combination with anti-PD-1 agents enhances therapeutic efficacy by augmenting the anti-tumoral immune response.

Neratinib and Ado-Trastuzumab-Emtansine for Pre-treated and Untreated HER2-positive Breast Cancer Brain Metastases: Translational Breast Cancer Research Consortium Trial 022.

PURPOSE: Treatment options for HER2-positive breast cancer brain metastases (BCBM) remain limited. We previously reported central nervous system (CNS) activity for neratinib and neratinib-capecitabine. Preclinical data suggest that neratinib may overcome resistance to ado-trastuzumab-emtansine (T-DM1) when given in combination. In TBCRC 022's cohort 4, we examined the efficacy of neratinib plus T-DM1 in patients with HER2-positive BCBM. PATIENTS AND METHODS: In this multicenter, phase II study, patients with measurable HER2-positive BCBM received neratinib 160 mg daily plus T-DM1 3.6 mg/kg intravenously every 21 days in three parallel-enrolling cohorts (cohort 4A-previously untreated BCBM, cohorts 4B and 4C- BCBM progressing after local CNS-directed therapy without [4B] and with [4C] prior exposure to T-DM1). Cycle 1 diarrheal prophylaxis was required. The primary endpoint was the Response Assessment in Neuro-Oncology-Brain Metastases (RANO-BM) by cohort. Overall survival (OS) and toxicity were also assessed. RESULTS: Between 2018-2021, 6, 17, and 21 patients enrolled to cohorts 4A, 4B, and 4C. Enrollment was stopped prematurely for slow accrual. The CNS objective response rate in cohorts 4A, 4B, and 4C was 33.3% (95% confidence interval [CI]: 4.3-77.7%), 35.3% (95% CI: 14.2-61.7%), and 28.6% (95% CI: 11.3-52.2%), respectively; 38.1-50% experienced stable disease for ≥6 months or response. Diarrhea was the most common grade 3 toxicity (22.7%). Median OS was 30.2 months (cohort 4A; 95% CI: 21.9, not reached [NR]), 23.3 months (cohort 4B; 95% CI: 17.6, NR), and 20.9 months (cohort 4C; 95% CI: 14.9, NR). CONCLUSION: We observed Intracranial activity for neratinib plus T-DM1, including those with prior T-DM1 exposure, suggesting synergistic effects with neratinib. Our data provide additional evidence for neratinib-based combinations in patients with HER2-positive BCBM, even those who are heavily pre-treated.

Trastuzumab deruxtecan versus trastuzumab emtansine in Asian patients with HER2-positive metastatic breast cancer.

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.

Trastuzumab-deruxtecan in solid tumors with HER2 alterations: from early phase development to the first agnostic approval of an antibody-drug conjugate.

INTRODUCTION: Antibody-drug conjugates (ADCs) represent a revolutionary approach in the systemic treatment for both solid and hematologic tumors. Constituted by an antibody, a cytotoxic payload, and a linker, ADCs aim to selectively deliver cytotoxic agents to tumors while sparing normal tissues. Various ADCs have been tested and approved for multiple solid tumors so far, but if there is one that had a major impact on clinical practice, this is Trastuzumab-deruxtecan (T-DXd). Notably, T-DXd was approved for HER2-positive and HER2-low metastatic breast cancer (MBC), HER2-positive gastric cancer (GC), HER2-mutant non-small cell lung cancer (NSCLC) and HER2 3+ solid tumors. Moreover, it received Breakthrough Therapy Designation for HER2-positive colorectal cancer (CRC). AREAS COVERED: We review preclinical and clinical data of T-DXd, focusing on early-phase ongoing trials exploring combination therapies to enhance the activity of T-DXd in HER2-expressing solid tumors. EXPERT OPINION: The clinical use of T-DXd still raises questions about selection of patients, treatment duration, prioritization over other approved ADCs, and management of resistance. Concerns regarding the toxicity of T-DXd remain, particularly with combinations involving potentially toxic drugs. Advancements in biomarker identification and combination therapies offer promising avenues to enhance efficacy and overcome resistance to T-DXd, ultimately improving outcomes for patients with cancer.

Monitoring changing patterns in HER2 addiction by liquid biopsy in advanced breast cancer patients.

BACKGROUND: During targeted treatment, HER2-positive breast cancers invariably lose HER2 DNA amplification. In contrast, and interestingly, HER2 proteins may be either lost or gained. To longitudinally and systematically appreciate complex/discordant changes in HER2 DNA/protein stoichiometry, HER2 DNA copy numbers and soluble blood proteins (aHER2/sHER2) were tested in parallel, non-invasively (by liquid biopsy), and in two-dimensions, hence HER2-2D. METHODS: aHER2 and sHER2 were assessed by digital PCR and ELISA before and after standard-of-care treatment of advanced HER2-positive breast cancer patients (n=37) with the antibody-drug conjugate (ADC) Trastuzumab-emtansine (T-DM1). RESULTS: As expected, aHER2 was invariably suppressed by T-DM1, but this loss was surprisingly mirrored by sHER2 gain, sometimes of considerable entity, in most (30/37; 81%) patients. This unorthodox split in HER2 oncogenic dosage was supported by reciprocal aHER2/sHER2 kinetics in two representative cases, and an immunohistochemistry-high status despite copy-number-neutrality in 4/5 available post-T-DM1 tumor re-biopsies from sHER2-gain patients. Moreover, sHER2 was preferentially released by dying breast cancer cell lines treated in vitro by T-DM1. Finally, sHER2 gain was associated with a longer PFS than sHER2 loss (mean PFS 282 vs 133 days, 95% CI [210-354] vs [56-209], log-rank test p=0.047), particularly when cases (n=11) developing circulating HER2-bypass alterations during T-DM1 treatment were excluded (mean PFS 349 vs 139 days, 95% CI [255-444] vs [45-232], log-rank test p=0.009). CONCLUSIONS: HER2 gain is adaptively selected in tumor tissues and recapitulated in blood by sHER2 gain. Possibly, an increased oncogenic dosage is beneficial to the tumor during anti-HER2 treatment with naked antibodies, but favorable to the host during treatment with a strongly cytotoxic ADC such as T-DM1. In the latter case, HER2-gain tumors may be kept transiently in check until alternative oncogenic drivers, revealed by liquid biopsy, bypass HER2. Whichever the interpretation, HER2-2D might help to tailor/prioritize anti-HER2 treatments, particularly ADCs active on aHER2-low/sHER2-low tumors. TRIAL REGISTRATION: NCT05735392 retrospectively registered on January 31, 2023 https://www. CLINICALTRIALS: gov/search?term=NCT05735392.

FINAL outcome ANALYSIS FROM THE PHASE II TUXEDO-1 TRIAL OF TRASTUZUMAB-DERUXTECAN IN HER2-positive breast cancer PATIENTS WITH active brain metastases.

BACKGROUND: Brain metastases (BM) are a devastating complication of HER2-positive metastatic breast cancer (BC) and treatment strategies providing optimized local and systemic disease control are urgently required. The antibody-drug conjugate (ADC) trastuzumab deruxtecan (T-DXd) improved progression-free survival (PFS) and overall survival (OS) over trastuzumab emtansine but data regarding intracranial activity is limited. In the primary outcome analysis of TUXEDO-1, a high intracranial response rate (RR) was reported with T-DXd. Here, we report final PFS and OS results. PATIENTS AND METHODS: TUXEDO-1 accrued adult patients with HER2-positive BC and active BM (newly diagnosed or progressing) without indication for immediate local therapy. The primary endpoint was intracranial RR; secondary endpoints included PFS, OS, safety, quality-of-life (QoL), and neurocognitive function. PFS and OS were estimated with the Kaplan-Meier method and analysed in the per-protocol population. RESULTS: At 26.5 months median follow-up, median PFS was 21 months (95% CI 13.3-n.r.) and median OS was not reached (95% CI 22.2-n.r.). With longer follow-up, no new safety signals were observed. The most common grade 3 adverse event was fatigue (20%). Grade 2 interstitial lung disease and a grade 3 symptomatic drop of left-ventricular ejection fraction were observed in one patient each. QoL was maintained over the treatment period. DISCUSSION: T-DXd yielded prolonged intra- and extracranial disease control in patients with active HER2-positive BC BM in line with results from the pivotal trials. These results support the concept of ADCs as systemic therapy for active BM.

Pharmacokinetics, Safety, Tolerability, and Immunogenicity of BP02 (Trastuzumab Biosimilar) Compared to EU- and US-Approved Trastuzumab in Healthy Adult Male Volunteers: A Phase 1, Randomized, Double-Blind Study.

INTRODUCTION: This study evaluated the pharmacokinetic (PK) equivalence between BP02 (a proposed trastuzumab biosimilar) and the reference trastuzumab approved in the EU (EU-trastuzumab) and the US (US-trastuzumab). METHODS: In this phase 1, double-blind, parallel-group trial, 111 healthy male volunteers were randomized 1:1:1 to receive a single 6-mg/kg intravenous infusion of BP02, EU-trastuzumab, or US-trastuzumab and were evaluated for 78 days. Serum drug concentration-time data were analyzed by non-compartmental methods. The PK similarity of BP02 to the two reference products, and between EU-trastuzumab and US-trastuzumab, was determined using the standard 80-125% bioequivalence criteria. RESULTS: Baseline demographics for the 111 subjects with evaluable pharmacokinetics were similar across all treatment groups. PK profiles were similar for the three products. The 90% confidence intervals (CIs) for the ratios of area under the serum concentration-time curve (AUC) from the time of dosing to infinity (AUC0-inf), AUC from the time of dosing until the time of the last quantifiable concentration (AUC0-t), and peak serum concentration of trastuzumab (Cmax) were within 80% to 125% for all three pairwise comparisons. Adverse events (AEs) were similar across all arms, with treatment-related AEs reported by 73.0%, 73.0%, and 89.2% of the subjects in the BP02, EU-trastuzumab, and US-trastuzumab groups, respectively. The most common AEs were headache, infusion-related reactions, and upper-respiratory-tract infections. Four subjects-three in the US-trastuzumab group and one in the BP02 group-discontinued the study due to AEs. All post-dose samples except for two tested negative for anti-drug antibodies. CONCLUSION: This study demonstrates the PK similarity among BP02, EU-trastuzumab, and US-trastuzumab. The safety and immunogenicity profiles observed for the three products in this study are consistent with previous reports for trastuzumab. TRIAL REGISTRATION: ANZCTR number: ACTRN12621000573853.

Trastuzumab, a monoclonal anti-HER2 antibody modulates cytotoxicity against cholangiocarcinoma via multiple mechanisms.

Cholangiocarcinoma (CCA) is an aggressive and fatal cancer. The prognosis is very poor and no optimal chemotherapy has been established. Human epidermal growth factor receptor 2 (HER2, neu, and erbB2) is highly-expressed in breast cancer and is expressed in many other tumors but poorly expressed in CCA. The anti-HER2 antibody, trastuzumab, has been used for the treatment of HER2-positive breast and gastric cancer. In this study, we examined the surface expression of HER2 on seven Thai liver-fluke-associated CCA cell lines by flow cytometry, and found all of these CCA cells were weakly positive for HER2. MTT assay revealed that trastuzumab directly suppressed the growth of CCA. By using FcR-bearing recombinant Jurkat T-cell-expressing firefly luciferase gene under the control of NFAT response elements, we defined the activities of antibody-dependent cytotoxicity (ADCC) and antibody-dependent cell phagocytosis (ADCP). ADCC was confirmed by using expanded NK cells. ADCP was confirmed by using mouse peritoneal macrophages and human monocyte-derived macrophages as effector cells. Rabbit serum was administered to test the complement-dependent cytotoxicity (CDC) activity of trastuzumab. Finally, we evaluated the efficacy of trastuzumab in in vivo patient-derived cell xenograft and patient-derived xenograft (PDX) models. Our results showed that a distinct population of CCA (liver-fluke-associated CCA) expressed HER2. Trastuzumab demonstrated a potent inhibitory effect on even HER2 weakly positive CCA both in vitro and in vivo via multiple mechanisms. Thus, HER2 is a promising target in anti-CCA therapy, and trastuzumab can be considered a promising antibody immunotherapy agent for the treatment of CCA.

A randomized phase 2 study of HLX22 plus trastuzumab biosimilar HLX02 and XELOX as first-line therapy for HER2-positive advanced gastric cancer.

BACKGROUND: Gastric cancer is the fifth most common cancer and the fourth most common cause of cancer death worldwide, yet the prognosis of advanced disease remains poor. METHODS: This was a randomized, double-blinded, phase 2 trial (ClinicalTrials.gov: NCT04908813). Patients with locally advanced/metastatic HER2-positive gastric/gastroesophageal junction cancer and no prior systemic antitumor therapy were randomized 1:1:1 to 25 mg/kg HLX22 (a novel anti-HER2 antibody) + HLX02 (trastuzumab biosimilar) + oxaliplatin and capecitabine (XELOX) (group A), 15 mg/kg HLX22 + HLX02 + XELOX (group B), or placebo + HLX02 + XELOX (group C) in 3-week cycles. Primary endpoints were progression-free survival (PFS) and objective response rate (ORR) assessed by independent radiological review committee (IRRC). FINDINGS: Between November 29, 2021, and June 6, 2022, 82 patients were screened; 53 were randomized to group A (n = 18), B (n = 17), and C (n = 18). With 14.3 months of median follow-up, IRRC-assessed median PFS was prolonged with the addition of HLX22 (A vs. C, 15.1 vs. 8.2 months, hazard ratio [HR] 0.5 [95% confidence interval (CI) 0.17-1.27]; B vs. C, not reached vs. 8.2 months, HR 0.1 [95% CI 0.04-0.52]). Confirmed ORR was comparable among groups (A vs. B vs. C, 77.8% vs. 82.4% vs. 88.9%). Treatment-related adverse events (TRAEs) were observed in 18 (100%), 16 (94.1%), and 17 (94.4%) patients, respectively. One (5.6%) patient in group C reported a grade 5 TRAE. CONCLUSIONS: Adding HLX22 to HLX02 and XELOX prolonged PFS and enhanced antitumor response in the first-line treatment of HER2-positive gastric cancer, with manageable safety. FUNDING: Shanghai Henlius Biotech, Inc.

Possible protective effect of rosuvastatin in chemotherapy-induced cardiotoxicity in HER2 positive breast cancer patients: a randomized controlled trial.

Cardiotoxicity is a side effect of chemotherapy in human epidermal growth factor receptor 2 (HER2) positive breast cancer patients receiving both anthracyclines and trastuzumab. We looked for a possible protective effect of rosuvastatin against chemotherapy-induced cardiotoxicity. Methods: 50 newly diagnosed HER2 positive breast cancer patients were randomly allocated into two groups: 25patients in each. Group 1(control group) received doxorubicin for 4 cycles (3 months) followed by trastuzumab adjuvant therapy. Group 2 (treatment group) received doxorubicin for 4 cycles (3 months) followed by trastuzumab adjuvant therapy and 20 mg of oral rosuvastatin 24 h before the first cycle of chemotherapy and once daily for the rest of the follow-up period (6 months). Transthoracic echocardiography was done, and blood samples were collected for patients 24 h before the initiation of therapy, after 3 months and after 6 months to assess serum levels of high sensitivity cardiac troponin I (hs-cTnI), Myeloperoxidase (MPO), Interleukin-6 (IL-6) and Alanine aminotransferase (ALT). The study was retrospectively registered in Clinical Trials.gov in April 2022. Its ID is NCT05338723. Compared to control group, Rosuvastatin-treated group had a significantly lower decline in LVEF after 3 months and after 6 months. They had significantly lower Hs-cTnI and IL-6 after 3 months and after 6 months, and significantly lower MPO after 6 months. Four patients in control group experienced cardiotoxicity while no one in rosuvastatin-treated group. Rosuvastatin attenuated cardiotoxicity, so it is a promising protective agent against chemotherapy-induced cardiotoxicity.

Lattice radiotherapy in inflammatory breast cancer: report of a first case treated with curative aim.

Inflammatory breast cancer (IBC) is a rare, aggressive form of breast cancer characterized by poor prognosis. The treatment requires a multidisciplinary approach, with neoadjuvant chemotherapy, surgery, and radiation therapy (RT). Particularly, high doses of conventional RT have been historically delivered in the adjuvant setting after chemotherapy and mastectomy or as radical treatment in patients ineligible for surgery. Here, we report the case of a 49-year-old woman patient with IBC unsuitable for surgery and treated with a combination of lattice RT and fractionated external beam RT concurrent with trastuzumab, with a curative aim. One year after RT, the patient showed a complete response and tolerable toxicities. This is the first reported case of a not-operable IBC patient treated with this particular kind of RT.

Real-world data on the efficacy and safety of trastuzumab emtansine in patients with metastatic breast cancer previously treated with pertuzumab: Turkish oncology group multicenter study.

We aimed to evaluate the efficacy and safety of trastuzumab emtansine in patients with metastatic breast cancer previously treated with pertuzumab plus trastuzumab and taxane. We reviewed the medical records of patients who were diagnosed with Human Epidermal Growth Factor Receptor 2 (HER-2) positive metastatic breast cancer and received pertuzumab and then TDM-1 between January 2014 and January 2021 from twenty- five cancer centers. The Kaplan- Meier method estimated progression-free survival (PFS) and overall survival (OS). Additionally, objective response rate (ORR), clinical benefit rate (CBR), and safety were evaluated. One hundred fifty-three patients were included,79.1% of the patients received TDM-1 in the second line, 90.8% had visceral metastasis, and 30.7% had central nervous system involvement. The PFS and OS of TDM-1 were evaluated according to the number of previous lines (on the 2nd line or more than two lines) metastatic sites (visceral and non-visceral) and the presence of central nervous metastasis. In TDM-1 therapy, PFS in second line therapy was ten months (95% CI: 7.7 - 12.2); this was statistically higher than later-line PFS, which was six months (95% CI: 3.3 to 8.6) (p = 0.004). The median OS time was 25 months (95% CI: 21.0 to 28.9) in patients treated with TDM-1 in the second line and 19 months (95% CI: 12.3 to 25.6) in patients who received later than the second line(p = 0.175). There were no significant differences in PFS time of patients with and without visceral and central nervous metastases. Our study showed that TDM-1 was also effective in patients using pertuzumab, contributes significantly to PFS when used in the second line compared to its use in the later line, and does not make any difference in OS.

Tyrosine kinase inhibitors in HER2-positive metastatic breast cancer with trastuzumab emtansine resistance: insights from a multicenter retrospective real-world study.

The use of trastuzumab emtansine (T-DM1) has revealed significant efficacy in HER2-positive metastatic breast cancer (MBC). However, optimal therapeutic strategies following T-DM1 failure remain a subject of debate in clinical practice. In this multicenter, retrospective, real-world study, we sought to examine the effectiveness and safety of tyrosine kinase inhibitors (TKIs) as a therapeutic strategy in HER2-positive MBC who developed T-DM1 resistance. Between September 2018 and December 2022, 66 patients were enrolled. The median progression-free survival of TKIs-based therapy was 10.1 months (95% CI, 4.7-15.6). Objective response rate and clinical benefit rate were 18.2 and 66.7%, respectively. TKIs-based therapy demonstrated better effectiveness in patients who had previously derived benefit from T-DM1 and featured acquired resistance to trastuzumab. The most common adverse events were diarrhea (36, 54.5%), hand-foot syndrome (31, 47.0%), and leucopenia (30, 45.5%). In conclusion, TKIs-based therapy showed promising effectiveness and safety in HER2-positive MBC patients after T-DM1 failure.