Trastuzumab Therapy Research Articles

ERBB2 Amplification and HER2 Expression in Salivary Duct Carcinoma: Evaluation of Scoring Guidelines and Potential for Expanded Anti-HER2 Therapy

Salivary duct carcinoma (SDC) is aggressive with limited therapeutic options. A subset of SDC display human epidermal growth factor receptor 2 (HER2) protein overexpression by immunohistochemistry, and some show ERBB2 gene amplification. Guidelines for HER2 scoring are not firmly established. Recent advances in breast carcinoma have established a role for anti-HER2 therapies in lesions with low HER2 expression lacking ERBB2 amplification. Delineating HER2 staining patterns in SDC is critical for evaluating anti-HER2 treatments. In total, 53 cases of SDC resected at our institution between 2004 and 2020 were identified. Androgen receptor (AR) and HER2 immunohistochemistry and ERBB2 fluorescence in situ hybridization were performed in all cases. AR expression was scored for percentage positive cells and categorized as positive (>10% of cells), low positive (1%-10%), or negative (<1%). HER2 staining levels and patterns were recorded, scored using 2018 ASCO/CAP guidelines, and categorized into HER2-positive (3+ or 2+ with ERBB2 amplification), HER2-low (1+ or 2+ without ERBB2 amplification), HER2-very low (faint staining in <10% of cells), or HER2-absent types. Clinical parameters and vital status were recorded. Median age was 70 years, with a male predominance. ERBB2-amplified tumors (11/53; 20.8%) presented at lower pT stages (pTis/pT1/pT2; P = .005, Fisher exact test) and more frequently had perineural invasion (P = .007, Fisher exact test) compared with ERBB2 nonamplified tumors; no other pathologic features differed significantly by gene amplification status. In addition, 2+ HER2 staining by 2018 ASCO/CAP criteria was most common (26/53; 49%); only 4 cases (8%) were HER2-absent status; 3+ HER2 staining was found in 9 tumors, and all were ERBB2 amplified. Six patients with HER2-expressing tumors received trastuzumab therapy, including 2 with ERBB2-amplified tumors. Overall survival and recurrence-free survival did not differ significantly based on ERBB2 status. This work suggests that 2018 ASCO/CAP guidelines for HER2 evaluation in breast carcinoma could be applied to SDC. Our findings also show broad overexpression of HER2 in SDC raising the possibility that more patients may benefit from anti-HER2–directed therapies.

Association between insulin resistance and cardiac remodeling in HER2-positive breast cancer patients: a real-world study

BackgroundInsulin resistance is an overlapping risk factor for both heart and breast cancer, while its interaction with cardiotoxicity in breast cancer (BC) patients is not clear. This study investigated the impact of insulin resistance on cardiac remodeling in patients with human epidermal growth factor receptor 2 (HER2)-positive BC during and after trastuzumab therapy in real-world clinical practice.MethodsHER2-positive BC patients who received trastuzumab treatment between December 2012 and December 2017 were reviewed and 441 patients with baseline metabolic indices and serial echocardiographic measurements (baseline, 6, 12, and 18 months) after trastuzumab therapy initiation were included. Repeated measurement analysis of variance was used to evaluate temporal trends in multiparameter echocardiography. Linear mixed model was applied to further evaluate the role of insulin resistance in forementioned changes. Correlation of homeostasis model assessment-estimated insulin resistance (HOMA-IR) and triglyceride-glucose index (TyG) levels to changes in echocardiography parameters was explored.ResultsOf 441 patients (mean age 54 ± 10 [SD] years), 61.8% received anthracycline-based chemotherapy, 33.5% received left-sided radiotherapy, 46% received endocrine therapy. No symptomatic cardiac dysfunction was observed over the therapy course. A total of 19 (4.3%) participants experienced asymptomatic cancer therapy-related cardiac dysfunction (CTRCD), and the peak onset time was 12 months after the initiation of trastuzumab. Albeit relatively low CTRCD incidence, cardiac geometry remodeling, especially left atrial (LA) dilation over therapy was notable and was more severe in high HOMA-IR and TyG level groups (P < 0.01). Noteworthy, a partial reversibility of cardiac remodeling was observed with treatment cessation. Additionally, HOMA-IR level positively correlated to changes in LA diameter from baseline to 12 months (r = 0.178, P = 0.003). No significant association (all P > 0.10) was detected between HOMA-IR or TyG level and dynamic left ventricular parameter evaluation. Multivariate linear regression analysis demonstrated that higher HOMA-IR level was an independent determinant for LA enlargement in BC patients during anti-HER2 targeted therapy course after adjusting for confounding risk factors (P = 0.006).ConclusionInsulin resistance was associated with left atrial adverse remodeling (LAAR) in HER2-positive BC patients that received standard trastuzumab therapy, indicating that insulin resistance could be a supplementation to baseline cardiovascular risk stratification proforma for HER2-targeted antitumor therapies.

Risk Factors for Infusion Reactions in Patients with Breast Cancer Administered Trastuzumab Therapy.

Trastuzumab is a humanized monoclonal antibody targeting human epidermal growth factor receptor 2 (HER2) that is indicated for the treatment of HER2-positive breast cancer. The administration of biologics, such as trastuzumab, frequently causes infusion reactions (IRs) with fever and chills. This study aimed to clarify the risk factors for IRs in trastuzumab therapy. Between March 2013 and July 2022, 227 patients with breast cancer who started trastuzumab therapy were included in this study. The severity of IRs was graded according to the Common Terminology Criteria for Adverse Events, Version 5.0. The incidence of IRs in trastuzumab therapy was 27.3% (62/227). Dexamethasone administration was significantly different between the IR and non-IR groups in patients receiving trastuzumab therapy (univariate analysis, p < 0.001; multivariate analysis, p = 0.0002). Without dexamethasone, the severity of IRs in the pertuzumab combination group (Grade 1, 8/65; Grade 2, 23/65) was significantly higher than that in the non-pertuzumab group (Grade 1, 9/37; Grade 2, 3/37; p < 0.05). Our findings suggest that the risk of IRs is significantly higher in patients not premedicated with dexamethasone in trastuzumab therapy and that the concomitant use of pertuzumab without dexamethasone increases the severity of IRs caused by trastuzumab.

The Effect of Adding Pertuzumab to Adjuvant Trastuzumab in Early HER2-Positive Breast Cancer

Objectives: In this trial, It has been investigated whether pertuzumab, when added to adjuvant trastuzumab and chemotherapy, improves outcomes among patients with HER2-positive early breast cancer in compares to patients who received only Herceptin&#x0D; Methods: After surgery and central HER2-positive confirmation, about randomly 220 patients assigned with high-risk HER2-positive, operable breast cancer to received Anthracycline based chemotherapy 3 cycles fallowed by Taxotere 3 + either pertuzumab + hercetin 3 or standard adjuvant Herceptin alone, 17 cycles in 1 year. The patients were followed up for 3 years.&#x0D; Results: Results were indicated that about 50% of the patients who were randomly assigned to arm A received pertuzumab+Herceptin 3 cycles every 3 weeks (110 patients) and arm B 50% (110 patients) received Herceptin alone 17 cycles every 3 weeks. Disease recurrence occurred in 12 patients (10.9 %) in the pertuzumab group and 8 patients (7.2%) in the arm B group (hazard ratio, 0.81; 95% confidence interval [CI], 0.66 to 1.00; P=0.045). The estimates of the 3-year rates of invasive-disease-free survival were 89% in the pertuzumab+ herceptin group and 93% in the herceptin group. Heart failure, cardiac death, and cardiac dysfunction were infrequent in both treatment groups. Diarrhea of grade 3 or higher occurred almost exclusively during chemotherapy and it was more frequent with pertuzumab than with group B (7.9% vs. 2.8%).&#x0D; Conclusions: The study showed that pertuzumab + Trastuzumab adjuvant in 3 cycles worse rates of invasive-disease-free survival among patients with HER2-positive, operable breast cancer in compares with classical trastuzumab alone in 17 cycles. Diarrhea was more common with pertuzumab than with classical Trastuzumab therapy.

Targeting CXCR4 abrogates resistance to trastuzumab by blocking cell cycle progression and synergizes with docetaxel in breast cancer treatment

BackgroundAlthough trastuzumab and other HER2-targeted therapies have significantly improved survival in patients with HER2 overexpressed or amplified (HER2+) breast cancer, a significant proportion of patients do not respond or eventually develop clinical resistance. Strategies to reverse trastuzumab resistance remain a high clinical priority. We were the first to report the role of CXCR4 in trastuzumab resistance. The present study aims to explore the therapeutic potential of targeting CXCR4 and better understand the associated mechanisms.MethodsImmunofluorescent staining, confocal microscopy analysis, and immunoblotting were used to analyze CXCR4 expression. BrdU incorporation assays and flow cytometry were used to analyze dynamic CXCR4 expression. Three-dimensional co-culture (tumor cells/breast cancer-associated fibroblasts/human peripheral blood mononuclear cells) or antibody-dependent cellular cytotoxicity assay was used to mimic human tumor microenvironment, which is necessary for testing therapeutic effects of CXCR4 inhibitor or trastuzumab. The FDA-approved CXCR4 antagonist AMD3100, trastuzumab, and docetaxel chemotherapy were used to evaluate therapeutic efficacy in vitro and in vivo. Reverse phase protein array and immunoblotting were used to discern the associated molecular mechanisms.ResultsUsing a panel of cell lines and patient breast cancer samples, we confirmed CXCR4 drives trastuzumab resistance in HER2+ breast cancer and further demonstrated the increased CXCR4 expression in trastuzumab-resistant cells is associated with cell cycle progression with a peak in the G2/M phases. Blocking CXCR4 with AMD3100 inhibits cell proliferation by downregulating mediators of G2-M transition, leading to G2/M arrest and abnormal mitosis. Using a panel of trastuzumab-resistant cell lines and an in vivo established trastuzumab-resistant xenograft mouse model, we demonstrated that targeting CXCR4 with AMD3100 suppresses tumor growth in vitro and in vivo, and synergizes with docetaxel.ConclusionsOur findings support CXCR4 as a novel therapeutic target and a predictive biomarker for trastuzumab resistance in HER2+ breast cancer.

Do tumor infiltrating lymphocytes (TILs) predict benefits from trastuzumab therapy for HER2 positive breast cancer? Meta-analysis of individual patient data from 4097 women in 5 trials.

508 Background: High TIL counts are associated with a lower risk of breast cancer recurrence, especially in women with ER negative, HER2 negative tumors and, possibly, greater benefit from trastuzumab in women with HER2 positive cancer: the FinHER trial reported a differential effect of trastuzumab based upon TIL status. We performed a meta-analysis of randomized trials of trastuzumab in early breast cancer to attempt to validate this finding. Methods: TILs were quantified in 4097 women in 5 randomized controlled trials (NSABP B-31, FinHER, HERA, Intergroup N9831, PACS-04). All trials contributed to the Early Breast Cancer Trialists' Collaborative Group individual patient data meta-analysis of trastuzumab for women with HER2 positive tumors which found a significant benefit for trastuzumab therapy. TILs were assessed using established International Guidelines, with HERA using digital TIL-scores. The primary outcome was time to first recurrence. Cox regression analyses, adjusted for trial, treatment allocation, and nodal status, were used to quantify the prognostic value of TILs; and standard stratified logrank tests were used to assess the differential effect of trastuzumab therapy. Results: The median percentage TILs was 13% (Interquartile Range 5-30), with fewer than 10% of patients exhibiting TILs &gt;50%. The prognostic value of TILs was confirmed, with patients with higher TILs being at lower risk for recurrence (adjusted hazard ratio per 10% increase in TILs 0.87 (95% CI 0.84-0.90), p&lt;.0001) with similar effects in both treatment groups. Outcomes improved steadily with increasing TILs, and unadjusted 10-year recurrence rates fell from 30% in women with TILs &lt;10% to 15% in those with TILs 70% or greater. Consequently, analyses of the predictive effect of TILs were stratified into 5 groups (0-9, 10-19, 20-39, 40-59, 60+). Overall, there was a highly significant benefit of trastuzumab on recurrence (HR 0.62 (0.54-0.70) p&lt;.0001), but there was no evidence of any interaction between TILs and the proportional reduction in recurrence (p=0.8 for heterogeneity and trend). Conclusions: While higher TILs are associated with lower recurrence rates, there was no indication that the proportional reduction in recurrence with trastuzumab varied by TILs, although the number of patients with high levels was limited. Owing to a lower underlying recurrence rate, absolute benefits from trastuzumab were lower, but still substantial, in women with high TIL tumors. Clinical trial information: NCT00045032 , ISRCTN76560285 , NCT00005970 , NCT00004067 , NCT00054587 . [Table: see text]

Pharmacological cardioprotective strategy for non-metastatic patients affected by breast cancer receiving an anthracycline-based chemotherapy: Final results of the phase 3 SAFE trial.

12079 Background: Several studies have evaluated cardioprotective strategies to prevent myocardial dysfunction in patients receiving cardiotoxic therapies. However, the optimal approach still represents a controversial issue. We aim to determine whether pharmacological cardiac prevention could reduce subclinical heart damage in breast cancer (BC) patients treated with anthracycline-based chemotherapy. Methods: The SAFE trial is a four-arm, randomised, phase 3, double-blind, placebo-controlled study. Patients were eligible for trial inclusion if they had indication to primary or postoperative systemic therapy using an anthracycline-based regimen. Patients with prior diagnosis of cardiovascular disease were excluded. Cardioprotective therapy (bisoprolol (B), ramipril (R), or both drugs (B+R), as compared to placebo) was administered for 1 year from the initiation of chemotherapy or until the end of trastuzumab therapy in case of HER2 positive patients. Doses for all groups were systematically up-titrated, up to the daily target dose of B (5 mg, once daily), R (5 mg, once daily), and placebo, if tolerated. The primary endpoint was defined as detection of any subclinical impairment (worsening ≥10%) in myocardial function and deformation measured with standard and 3-dimensional (3D) echocardiography, left ventricular ejection fraction (LVEF) and global longitudinal strain (GLS). Results: 262 women (median 48 years; range24-75 years) were enrolled and treated in the study. We analysed patients who had completed the pre-planned cardiological assessment at 24 months. All patients received an anthracycline-based chemotherapy, 215 patients received at least 3 cycles of anthracyclines (range 1-6) and 128 patients had postoperative radiation therapy. At Univariate logistic analysis to evaluate the risk of GLS worsening &gt; 10% at 24 months, Odds ratios (OR) for improvement were 0.055, 0.083 and 0.060 for B, R and B+R, respectively (P &lt; 0.0001), if compared to placebo arm. At Univariate logistic analysis to evaluate the risk of 3DLVEF worsening &gt; 10% at 24 months, OR for improvement were 0.019, 0.048 and 0.054 for B, R and B+R, respectively (P &lt; 0.0001), if compared to placebo arm. Study drugs were well tolerated with no serious adverse events, the ramipril plus bisoprolol arm showed significantly more toxic effects and had a significantly higher rate of allocated treatment discontinuation as compared to the other arms. Conclusions: Cardioprotective pharmacological strategies in patients affected by BC receiving an anthracycline-based chemotherapy are well tolerated and seem to protect against cancer therapy-related LVEF decline and heart remodelling. Clinical trial information: NCT2236806 .

Quantitative cardiovascular magnetic resonance findings and clinical risk factors predict cardiovascular outcomes in breast cancer patients.

Cardiac magnetic resonance (CMR) global longitudinal strain and circumferential strain abnormalities have been associated with left ventricular ejection fraction (LVEF) reduction and cardiotoxicity from oncologic therapy. However, few studies have evaluated the associations of strain and cardiovascular outcomes. To assess CMR circumferential and global longitudinal strain (GLS) correlations with cardiovascular outcomes including myocardial infarction, systolic dysfunction, diastolic dysfunction, arrhythmias and valvular disease in breast cancer patients treated with and without anthracyclines and/or trastuzumab therapy. Breast cancer patients with a CMR from 2013-2017 at Yale New Haven Hospital were included. Patient co-morbidities, medications, and cardiovascular outcomes were obtained from chart review. Biostatistical analyses, including Pearson correlations, competing risk regression model, and competing risk survival curves comparing the two groups were analyzed. 116 breast cancer with CMRs were included in our analysis to assess differences between Anthracycline/Trastuzumab (AT) (62) treated versus non anthracycline/trastuzumab (NAT) (54) treated patients in terms of imaging characteristics and outcomes. More AT patients 17 (27.4%) developed systolic heart failure compared to the NAT group 6 (10.9%), p = 0.025. Statin use was associated with a significant reduction in future arrhythmias (HR 0.416; 95% CI 0.229-0.755, p = 0.004). In a sub-group of 13 patients that underwent stress CMR, we did not find evidence of microvascular dysfunction by sub-endocardial/sub-epicardial myocardial perfusion index ratio after adjusting for ischemic heart disease. In our study, CMR detected signs of subclinical cardiotoxicity such as strain abnormalities despite normal LV function and abnormal circumferential strain was associated with adverse cardiovascular outcomes such as valvular disease and systolic heart failure. Thus, CMR is an important tool during and after cancer treatment to identity and prognosticate cancer treatment-related cardiotoxicity.

Development and Validation of the ELISA Method for Neutralizing Anti-trastuzumab Antibodies Detection in Human Blood Serum

Introduction. Trastuzumab is the first known anti-HER2 agent, which revolutionized the treatment of one of the most common cancer types – breast cancer. Despite trastuzumab being approved long time ago, further improvement of related analytical methods remains relevant primarily due to the emergence of new biosimilars. For instance, immunogenicity – adverse reaction which is usually associated with biological drugs, can still be relevant for trastuzumab. Anti-drug antibodies, including neutralizing antibodies, caused by trastuzumab therapy, can affect drug effectiveness and safety profile.Aim. The aim of this study was to develop and validate the analytical method for neutralizing anti-trastuzumab antibodies determination in human blood serum.Materials and methods. The neutralizing anti-trastuzumab antibody determination was carried out by the competitive ELISA method, using spectrophotometric detection in the visible range of the spectrum.Results and discussion. The developed method was validated for cut-point, selectivity, sensitivity, specificity, precision and stability (short-term and long-term). To decrease the background noise from non-specific binding of sera components, the minimum required dilution value was determined at 0.5 % serum. The calculated value for cut-point was 14.62 %. The sensitivity of the developed method was estimated at 1985.2 ng/mL of neutralizing anti-trastuzumab antibodies.Conclusion. The obtained results allowed us to apply the developed ELISA method for the neutralizing anti-trastuzumab antibodies determination in human blood serum during trastuzumab immunogenicity assessment in bioequivalence clinical trials.

Effect of adjuvant trastuzumab for HER2 positive breast cancer combined with radiation therapy and anthracyclines on left ventricular function

Abstract Funding Acknowledgements Type of funding sources: None. Background Although trastuzumab has benefits in treatment of HER2 positive breast cancer, its use is associated with an increased risk of cardiotoxicity. Purpose To assess the effect of adjuvant trastuzumab in HER2 positive breast cancer pts, in addition to prior radiation and antracyclines therapy, on left ventricular function. Methods Fifty HER2 positive female breast cancer patients (mean age, 59.57±9.6 years) were enrolled in the study. In all patients (pts) left ventricular left ventricular ejection fraction-LVEF(%) and left ventricular mass – LVM (g) were assesed at the beginning and after the therapy with trastuzumab. All pts were on sequential therapy with anthracyclines (IV cycles) within the FAC regimen (fluorouracil 500 mg/m2, doxorubicin 50 mg/m2, cyclophosphamide 500 mg/m2) on day 21, and after that followed with trastuzumab (6 mg/kg of body weight on day 21) for the period of one year. The pts are divided in two groups: the group of patients (N=32 pts) who had prior radiation therapy (25 daily sessions of 2 Gy dose each, up to the total dose of 50 Gy) and group without radiation therapy (N=18). Results After completion of trastuzumab therapy pts who underwent radiation therapy, reduced LVEF by 2.24 % (from 66.58 ± 5.36 % to 64.34±7.34 %; p=0.048) and increased LVM by 17.95 g (from 160.38 ± 46.21 g to 178.33 ± 53.14 g; p=0.018) . The group of pts without radiation therapy, reduced LVEF by 0,72 % (from 63.33±7.60 % to 62.61±6.92 %; p=0.979) and increased LVM 23.34 g (from 141.98±35.82 g to 165.32±47.45 g; p=0.062). Conclusion The results of the study showed that the decline of LVEF and increase of LVM after completion of adjuvant trastuzumab therapy for HER2 positive breast cancer iz related with previous prior radiation administration. The pts with radiation had greater reduction of LVEF and increase of LVM than those without radiation.

Development of cardiac risk prediction model in patients with HER-2 positive breast cancer on trastuzumab therapy

Background25% of all breast cancer patients have HER-2 overexpression. Breast Cancer patients with HER-2 overexpression are typically treated with HER-2 inhibitors such as Trastuzumab. Trastuzumab is known to cause a decrease in left ventricular ejection fraction. The aim of this study is to create a cardiac risk prediction tool among women with Her-2 positive breast cancer to predict cardiotoxicity.MethodUsing a split sample design, we created a risk prediction tool using patient level data from electronic medical records. The study included women 18 years of age and older diagnosed with HER-2 positive breast cancer who received Trastuzumab. Outcome measure was defined as a drop in LVEF by more than 10% to less than 53% at any time in the 1-year study period. Logistic regression was used to test predictors.ResultsThe cumulative incidence of cardiac dysfunction in our study was 9.4%. The sensitivity and specificity of the model are 46% and 84%, respectively. Given a cumulative incidence of cardiotoxicity of 9%, the negative predictive value of the test was 94%. This suggests that in a low-risk population, the interval of screening for cardiotoxicity may be performed less frequently.ConclusionCardiac risk prediction tool can be used to identify Her-2 positive breast cancer patients at risk of developing cardiac dysfunction. Also, test characteristics in addition to disease prevalence may inform a rational strategy in performing cardiac ultrasound in Her-2 breast cancer patients. We have developed a cardiac risk prediction model with high NPV in a low-risk population which has an appealing cost-effectiveness profile.

Genetic mutations in HER2-positive breast cancer: possible association with response to trastuzumab therapy

BackgroundHER2-positive breast cancer occurs in 15–20% of breast cancer patients and is characterized by poor prognosis. Trastuzumab is considered the key drug for treatment of HER2-positive breast cancer patients. It improves patient survival; however, resistance to trastuzumab remains a challenge in HER2-positive breast cancer patients. Therefore, the prediction of response to trastuzumab is crucial to choose optimal treatment regimens. The aim of the study was to identify genetic variants that could predict response to anti-HER2-targeted therapy (trastuzumab) using next-generation sequencing.MethodGenetic variants in the hotspot regions of 17 genes were studied in 24 Formalin-Fixed Paraffin-Embedded (FFPE) samples using Ion S5 next-generation sequencing system. FFPE samples were collected from HER2‑positive breast cancer patients previously treated with anti‑HER2‑targeted treatment (Trastuzumab). Patients were divided into two groups; trastuzumab-sensitive group and trastuzumab-resistant group based on their response to targeted therapy.ResultsWe identified 29 genetic variants in nine genes that only occurred in trastuzumab-resistant patients and could be associated with resistance to targeted therapy including TP53, ATM, RB1, MLH1, SMARCB1, SMO, GNAS, CDH1, and VHL. Four variants out of these 29 variants were repeated in more than one patient; two variants in TP53, one variant in ATM gene, and the last variant in RB1 gene. In addition, three genes were found to be mutated only in resistant patients; MLH1, SMARCB1 and SMO genes. Moreover, one novel allele (c.407A > G, p. Gln136Arg) was detected within exon 4 of TP53 gene in one resistant patient.ConclusionNGS sequencing is a useful tool to detect genetic variants that could predict response to trastuzumab therapy.

Pathogenic HER3 dimerization domain mutations create a structural bias towards un-conventional EGFR-HER3 signalling axis in breast cancer

Among the EGFR family of receptors, HER3 is considered as a pseudo-kinase which primarily interacts with HER2 in presence of heregulin-1β. We identified two hotspot mutations i.e. G284R and D297Y and one double mutant HER2-S310F/HER3-G284R in breast cancer patients. Long term MDS (7.5 μs) revealed that HER3-D297Y and HER2-S310F:HER3-G284R do not allow the interaction with HER2 as these mutations cause dramatic conformational changes in its flanking regions. This results in formation of an unstable HER2-WT:HER3-D297Y heterodimer, thereby abrogating the downstream signalling by AKT. We found that His228 and Ser300 of HER3-D297Y form stable interactions with Glu245 and Tyr270 of EGFR-WT, in the presence of either EGF or heregulin-1β. Applying TRIM-ing mediated direct knockdown of endogenous EGFR protein, specificity of the unconventional EGFR:HER3-D297Y interaction was validated. Due to this unusual ligand mediated interaction, cancer cells were found susceptible to EGFR targeted therapeutics i.e. Gefitinib and Erlotinib. Further, in TCGA analysis, BC patients harbouring HER3-D297Y mutation showed increased p-EGFR levels as compared to the patients harbouring HER3-WT and HER3-G284R mutations. For the first time, this comprehensive study showed the importance of specific hotspot mutations in HER3 dimerization domain can defy the Trastuzumab therapy, rather cells become susceptible to the EGFR inhibitors.

Meta-analysis of Clinical Efficacy and Safety of Pertuzumab and Trastuzumab Combined Therapy in HER-2 Positive Breast Cancer

Objective: To systematically evaluate the clinical efficacy and safety of pertuzumab and trastuzumab combined therapy in human epidermal growth factor receptor 2 (HER-2) positive breast cancer through a meta-analysis. Methods: English databases including PubMed, Embase, and the Cochrane Central Register of Controlled Trials, as well as Chinese databases including China National Knowledge Infrastructure, Wanfang Database, and the Chinese Biomedical Literature Service System (Sinomed), were searched for randomized controlled trials (RCTs) comparing pertuzumab and trastuzumab combined therapy (experimental group) with trastuzumab alone (control group) for the treatment of HER-2 positive breast cancer. The literature search time was from the establishment of the database to July 2022. Two reviewers independently screened the literature, extracted data, and assessed the quality of the literature. Meta-analysis was performed using Review Manager 5.4 software. Results: A total of 9 RCTs involving 7199 patients were included in the meta-analysis. The results of the effectiveness indicators showed that the risk of tumor progression in HER-2 positive breast cancer patients receiving dual-targeted therapy was significantly lower than that in patients receiving trastuzumab alone [Hazard ratios (HR) = 0.68, 95% confidence intervals (CI) (0.58, 0.79), P&lt;0.00001]; the overall survival (OS) of HER-2 positive breast cancer patients receiving dual-targeted therapy was significantly longer than that of patients receiving trastuzumab alone [HR=0.73, 95% CI (0.59, 0.88), P&lt;0.0009]. In terms of safety, there was no statistical difference in the incidence of severe adverse events and ≥3 grade neutropenia between the experimental and control groups (P&gt;0.05), but the incidence of ≥3 grade diarrhea in the experimental group was significantly higher than that in the control group [relative risks = 2.44, 95% CI (1.95, 2.99), P&lt;0.00001]. Conclusion: The combined therapy of pertuzumab and trastuzumab has significant clinical efficacy in HER-2 positive breast cancer patients, and its application can further improve patients' progression-free survival and OS. However, it also increases the risk of adverse reactions to a certain extent. Therefore, in clinical practice, it is necessary to strengthen the monitoring and protection of relevant adverse reactions in patients.

Exploring potential molecular resistance and clonal evolution in advanced HER2-positive gastric cancer under trastuzumab therapy

HER2-positive gastric cancer (GC) makes up 15–20% of all GC incidences, and targeted therapy with trastuzumab is the standard of treatment. However, the mechanisms of resistance to trastuzumab are still not fully understood and presents a significant challenge in clinical practice. In this study, whole exome sequencing (WES) was performed on paired tumor tissues before trastuzumab treatment (at baseline) and at progressive disease (PD) in 23 GC patients. Clinicopathological and molecular features that may be associated with primary and/or acquired resistance to trastuzumab were identified. Lauren classification of intestinal type was associated with a more prolonged progression-free survival (PFS) than diffuse type (HR = 0.29, P = 0.019). Patients with low tumor mutation burden (TMB) showed significantly worse PFS, while high chromosome instability (CIN) was correlated with prolonged OS (HR = 0.27; P = 0.044). Patients who responded to treatment had a higher CIN than nonresponders, and a positive trend towards increasing CIN was observed as response improved (P = 0.019). In our cohort, the most common genes to acquire mutations are AURKA, MYC, STK11, and LRP6 with four patients each. We also discovered an association between clonal branching pattern and survival, with an extensive clonal branching pattern being more closely related to a shorter PFS than other branching patterns (HR = 4.71; P = 0.008). We identified potential molecular and clinical factors that provide insight regarding potential association to trastuzumab resistance in advanced HER2-positive GC patients.

Comprehensive Cardiovascular Magnetic Resonance Tissue Characterization and Cardiotoxicity in Women With Breast Cancer

There is a growing interest in understanding whether cardiovascular magnetic resonance (CMR) myocardial tissue characterization helps identify risk of cancer therapy-related cardiac dysfunction (CTRCD). To describe changes in CMR tissue biomarkers during breast cancer therapy and their association with CTRCD. This was a prospective, multicenter, cohort study of women with ERBB2 (formerly HER2)-positive breast cancer (stages I-III) who were scheduled to receive anthracycline and trastuzumab therapy with/without adjuvant radiotherapy and surgery. From November 7, 2013, to January 16, 2019, participants were recruited from 3 University of Toronto-affiliated hospitals. Data were analyzed from July 2021 to June 2022. Sequential therapy with anthracyclines, trastuzumab, and radiation. CMR, high-sensitivity cardiac troponin I (hs-cTnI), and B-type natriuretic peptide (BNP) measurements were performed before anthracycline treatment, after anthracycline and before trastuzumab treatment, and at 3-month intervals during trastuzumab therapy. CMR included left ventricular (LV) volumes, LV ejection fraction (EF), myocardial strain, early gadolinium enhancement imaging to assess hyperemia (inflammation marker), native/postcontrast T1 mapping (with extracellular volume fraction [ECV]) to assess edema and/or fibrosis, T2 mapping to assess edema, and late gadolinium enhancement (LGE) to assess replacement fibrosis. CTRCD was defined using the Cardiac Review and Evaluation Committee criteria. Fixed-effects models or generalized estimating equations were used in analyses. Of 136 women (mean [SD] age, 51.1 [9.2] years) recruited from 2013 to 2019, 37 (27%) developed CTRCD. Compared with baseline, tissue biomarkers of myocardial hyperemia and edema peaked after anthracycline therapy or 3 months after trastuzumab initiation as demonstrated by an increase in mean (SD) relative myocardial enhancement (baseline, 46.3% [16.8%] to peak, 56.2% [18.6%]), native T1 (1012 [26] milliseconds to 1035 [28] milliseconds), T2 (51.4 [2.2] milliseconds to 52.6 [2.2] milliseconds), and ECV (25.2% [2.4%] to 26.8% [2.7%]), with P <.001 for the entire follow-up. The observed values were mostly within the normal range, and the changes were small and recovered during follow-up. No new replacement fibrosis developed. Increase in T1, T2, and/or ECV was associated with increased ventricular volumes and BNP but not hs-cTnI level. None of the CMR tissue biomarkers were associated with changes in LVEF or myocardial strain. Change in ECV was associated with concurrent and subsequent CTRCD, but there was significant overlap between patients with and without CTRCD. In women with ERBB2-positive breast cancer receiving sequential anthracycline and trastuzumab therapy, CMR tissue biomarkers suggest inflammation and edema peaking early during therapy and were associated with ventricular remodeling and BNP elevation. However, the increases in CMR biomarkers were transient, were not associated with LVEF or myocardial strain, and were not useful in identifying traditional CTRCD risk.

Autoimmune hypothyroidism and trastuzumab therapy: a rare association.

We report a case of a woman with a diagnosis of breast cancer who unintentionally started gaining weight, feeling tired, and constipated 44 weeks after the initiation of trastuzumab. Hypothyroidism secondary to an autoimmune thyroiditis associated with trastuzumab was diagnosed, the first case described in Portugal and the fourth case described worldwide. Our intention regarding the publication of this case report is to alert the clinicians treating people with trastuzumab that they should ask the patients about symptoms of hypothyroidism and should screen the thyroid function of the patients before, during, and after the initiation of trastuzumab. Trastuzumab is a humanized MAB used in HER2-positive breast and gastric cancer. Trastuzumab-associated autoimmune thyroid disease (AITD) is rare (incidence rate in an RCT of 0.3%). Manifestations of autoimmune thyroiditis associated with trastuzumab resemble those of hypothyroidism in other clinical contexts, but the presence of goiter is highlighted as a reason for medical evaluation. Biochemically, it is characterized by an increased thyroid-stimulating hormone (TSH) with or without a low FT4/FT3, and sonographically with a pattern of thyroiditis. The treatment consists of levothyroxine, in a dose of 1.6-1.8 µg/kg/day, with re-evaluation of the thyroid function in 4-6 weeks. We report the first case of autoimmune thyroiditis secondary to trastuzumab in Portugal. It is important to evaluate the thyroid function before, during, and after the initiation of this therapeutic agent.

Statins enhance the efficacy of HER2-targeting radioligand therapy in drug-resistant gastric cancers

Human epidermal growth factor receptor2 (HER2) is overexpressed in various cancer types. HER2-targeting trastuzumab plus chemotherapy is used as first-line therapy for HER2-positive recurrent or primary metastatic gastric cancer, but intrinsic and acquired trastuzumab resistance inevitably develop over time. To overcome gastric cancer resistance to HER2-targeted therapies, we have conjugated trastuzumab with a beta-emitting therapeutic isotope, lutetium-177, to deliver radiation locally to gastric tumors with minimal toxicity. Because trastuzumab-based targeted radioligand therapy (RLT) requires only the extramembrane domain binding of membrane-bound HER2 receptors, HER2-targeting RLT can bypass any resistance mechanisms that occur downstream of HER2 binding. Leveraging our previous discoveries that statins, a class of cholesterol-lowering drugs, can enhance the cell surface-bound HER2 to achieve effective drug delivery in tumors, we proposed that the combination of statins and [177Lu]Lu-trastuzumab-based RLT can enhance the therapeutic efficacy of HER2-targeted RLT in drug-resistant gastric cancers. We demonstrate that lovastatin elevates cell surface HER2 levels and increases the tumor-absorbed radiation dose of [177Lu]Lu-DOTA-trastuzumab. Furthermore, lovastatin-modulated [177Lu]Lu-DOTA-trastuzumab RLT durably inhibits tumor growth and prolongs overall survival in mice bearing NCI-N87 gastric tumors and HER2-positive patient-derived xenografts (PDXs) of known clinical resistance to trastuzumab therapy. Statins also exhibit a radioprotective effect, reducing radiotoxicity in a mice cohort given the combination of statins and [177Lu]Lu-DOTA-trastuzumab. Since statins are commonly prescribed to patients, our results strongly support the feasibility of clinical studies that combine lovastatin with HER2-targeted RLT in HER2-postive patients and trastuzumab-resistant HER2-positive patients.

NONHSAT021545/miR-330-3p/EREG: A Cooperative Axis in Breast Cancer Prognosis and Treatment

Lymphatic metastasis is the most common form in breast cancer (BC) progression. Previously, we observed that lnc045874, a most conservative homology of Homo Sapiens NONHSAT021545 (lnc021545), miR-330-3p, and EREG may have some effects in mouse hepatocarcinoma cell lines with different lymphatic metastasis potentials. Through data from TCGA and GEO database analysis, we speculated that miR-330-3p might be a tumor promoter, while EREG could be a tumor suppressor in BC. MiR-330-3p was upregulated, while lnc021545 and EREG were downregulated in 50 BC tissues. MiR-330-3p advanced the metastatic behaviors of BC cells, whereas lnc021545 and EREG resulted in the opposite effects. The three molecules' expressions were correlated respectively and showed that miR-330-3p targeted lnc021545 and EREG to affect their expressions. Lnc021545/miR-330-3p axis affected BC metastasis by regulating EREG in epithelial-to-mesenchymal transition. In 50 BC patients, these three molecules and their cooperation are associated with aggressive tumor phenotypes, patient outcomes, and trastuzumab therapy. We finally discovered that lnc021545, miR-330-3p, and EREG formed a multi-gene co-regulation system that affected the metastasis of BC and the cooperation reflects the synergistic effects of the three molecules, recommending that their cooperation may provide a more accurate index for anti-metastasis therapeutic and prognostic evaluation of BC.

Abstract P4-02-05: Predictors of long-term durable response in de novo HER2 positive metastatic breast cancer and the real world treatment experience at two institutions

Abstract Purpose Modern HER2-directed therapies enable some patients with de novo HER2+ metastatic breast cancer (MBC) to achieve long-term, durable responses (DR), which can be defined as no progression of disease since initial diagnosis. Clinical and pathologic factors that predict DR continue to be elucidated. Expert opinion dictates indefinite HER2-directed therapies for patients who achieve DRs, but real-world examples of this practice are lacking in the literature. Methods This is a retrospective study of all patients with de novo HER2+ MBC at two major academic institutions who received at least one dose of trastuzumab between 2012-2019. DR is defined as absence of progression/death at any point after diagnosis. Controls are patients with evidence of progression/death. Age, ER/PR status, sites of metastasis, surgical resection of primary tumor and initial treatment were analyzed as predictors of DR using an unpaired T test, with p&amp;lt; 0.05 chosen as threshold for significance. For patients with DR, time to complete (CR) and partial response (PR) according to RECIST 1.1 were recorded, as was the duration and treatment patterns surrounding trastuzumab and pertuzumab. Patients were defined as having cardiotoxicity if they experienced a decline in cardiac ejection fraction at any point while on trastuzumab therapy leading to treatment delays or discontinuation. Results 96 patients with de novo HER2+ MBC, 28 with DR and 68 with progression, were identified. The average follow up of patients with DR was 90 months (range 27-224), compared to 58 months (range 1-208) in controls. The entire cohort of 96 patients had a median PFS of 23.5 months and a median OS of 88 months. Among the 28 patients with DR, 2 achieved stable disease, 10 patients had documented PR at 4 months on average (range 2-6 months), and 26 patients had CR at 7.7 months on average (range 2-19 months). Among patients with DR, nine patients have been receiving trastuzumab for over ten years with no evidence of disease and one patient opted to discontinue trastuzumab. 75% of patients with DR had a single metastatic site, compared with 47% of patients with progression (OR 3.7, p=0.01). 64% of patients with DR received a regimen containing trastuzumab, pertuzumab, and a taxane, while 28% of patients who progressed did (OR 4.5, p&amp;lt; 0.001). 57% of patients with DR underwent surgical removal of breast primary, compared with 24% of patients who progressed (OR 4.3, p=0.002.) Age, and ER/PR status did not predict DR. (Table 1) Six patients (6.3%) developed reduced ejection fraction requiring treatment interruption or cessation, five in the group who progressed, one in the DR group. Conclusion Nearly a third of patients with de novo HER2+ MBC achieved DR. Factors that correlate with DR include single metastatic site, initial trastuzumab, pertuzumab and taxane therapy, and surgical resection of primary tumor. This suggests that in selected patients, a more aggressive up front approach including surgical resection, and agents such as carboplatin, and trastuzumab deruxtecan deserves further study. Among patients with DR, indefinite trastuzumab administration is the norm with minimal cardiotoxicity but the impact of this on quality of life and financial toxicity are not well described. Table 1: Clinical characteristics of de novo HER2 positive metastatic breast cancer that predict durable response Citation Format: Claire E. Smith, Paul K. Marcom, Mitri Zahi, Naomi Ko. Predictors of long-term durable response in de novo HER2 positive metastatic breast cancer and the real world treatment experience at two institutions [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P4-02-05.