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Objective: Pyrotinb has been approved for the treatment of HER2-positive advanced or metastatic breast cancer in China. However, the plasma concentration of pyrotinb in different patients varies greatly, and in the course of treatment, if patients have intolerable adverse reactions, the drug dosage will be reduced or even stopped. This study set out to establish an ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) for the determination of pyrotinb in human plasma, analyze the population pharmacokinetics (PPK) of pyrotinib and assess the influence of patient variables on PK of pyrotinib in patients with HER2 positive breast cancer. Method: An UPLC-MS/MS method was developed to measure pyrotinib in human plasma. Utilizing a gradient elution procedure and a Kinetex C18 column (2.1 mm × 100 mm, 1.7 µm), sample separation was accomplished in 5.5 min. Pyrotinb extraction via protein precipitation was used as a sample pre-treatment technique. In total, 50 patients provided 158 plasma samples, which were identified and used in the PPK investigation. The non-linear mixed-effects modeling (NONMEM) approach was used to assess the plasma concentrations and covariates information. For the final PPK model evaluation, external evaluation, non-parametric bootstrap, visual predictive check (VPC), and goodness-of-fit (GOF) were used. Results: The UPLC-MS/MS method for determining plasma concentration of pyrotinib in patients had good selectivity and linearity in the range of 1-1,000 ng/mL. Pyrotinib concentration profile in HER2-positive breast cancer patients was well described by a single-compartment PPK model with first-order absorption and elimination. The formulas for the final estimated values of overall parameters of CL/F and Vd/F and Ka are respectively: CL/F(L/h) x 88.8 × e(TP/67.2)×0.376, V/F(L) x 3940, KA(h-1) x 0.357FIXED. No dosage adjustment was advised, despite the possibility that the total protein levels could have a substantial impact on the apparent distribution volume of pyrotinib with limited magnitude. Conclusion: In this study, an UPLC-MS/MS method was established to determine the concentration of pyrotinib in human plasma. A population pharmacokinetic model of pyrotinib in HER2 positive breast cancer patients suggested that low serum total protein reduced the clearance rate of pyrotinib in patients. Clinical medical staff should pay attention to the liver function of patients with abnormal serum total protein and be alert to the occurrence of adverse drug reactions. [ABSTRACT FROM AUTHOR]

Background: The management of early breast cancer (BC) has witnessed an uprise in the use of neoadjuvant therapy and a remarkable reshaping of the systemic therapy postneoadjuvant treatment in the last few years, with the evolution of many controversial clinical situations that require consensus. Methods: During the 14th Breast‐Gynecological and Immuno‐Oncology International Cancer Conference held in Egypt in 2022, a panel of 44 BC experts from 13 countries voted on statements concerning debatable challenges in the neo/adjuvant treatment setting. The recommendations were subsequently updated based on the most recent data emerging. A modified Delphi approach was used to develop this consensus. A consensus was achieved when ≥75% of voters selected an answer. Results and Conclusions: The consensus recommendations addressed different escalation and de‐escalation strategies in the setting of neoadjuvant therapy for early BC. The recommendations recapitulate the available clinical evidence and expert opinion to individualize patient management and optimize therapy outcomes. Consensus was reached in 63% of the statements (52/83), and the rationale behind each statement was clarified. Consensus recommendations of the 14th Breast‐Gynecological and Immuno‐Oncology International Cancer Conference recapitulate the available clinical evidence and expert opinion to individualize and optimize the neoadjuvant therapy of breast cancer. [ABSTRACT FROM AUTHOR]

Purpose: While 18F-FDG PET/CT (FDG-PET/CT) is consensual for clinical stage ≥ IIB breast cancers (BC), its benefit for stage I or IIA HER2+ or triple-negative breast cancer (TNBC) patients lacks sufficient evidence. We reported a single-institution, retrospective study evaluating FDG-PET/CT impact on patient management and staging for stage I or IIA HER2+ or Triple-Negative BC. Methods: Patients who underwent FDG-PET/CT staging before any treatment between January 2015 and December 2020 at Oscar Lambret Center were included. Exclusions: patients with symptoms or conventional imaging suggestive of metastatic dissemination, or with prior malignancies. Initial stage was determined from mammography, breast ultrasound, breast MRI, and clinical examination. Staging and therapeutic impact based on FDG-PET/CT findings collected, including intra- (modification of dose/site/strategy in a type of management previously indicated) and inter-modality (modification of planned treatment strategy) changes. Results: The cohort included 287 female patients with clinical stage I or IIA, HER2+ , or TNBC. Therapeutic impact observed for 18% of patients (n = 52), with 2% (n = 7) undergoing inter-modality change with omission of planned surgery. The impact on patient management was higher for stage IIA patients (20%, 47/237) than for stage I patients (10%, 5/50). Among stage IIA disease, changes in management were more important for T2N0 patients (22%, 44/205) than for T1N1 patients (9%, 3/32). While not statistically significant, trends suggest usefulness of FDG-PET/CT for T2N0 patients. Conclusion: Considering substantial therapeutic implications, our study suggests the usefulness of FDG-PET/CT for patients with stage IIA, HER2-positive, or Triple-Negative BC with tumor size > 2 cm (T2N0). [ABSTRACT FROM AUTHOR]

Breast cancer (BC) has the second highest incidence among cancers and is the leading cause of death among women worldwide. The human epidermal growth factor receptor 2 (HER2) is overexpressed in approximately 20%--30% of BC patients. The development of HER2-targeted drugs, including monoclonal antibodies (mAbs), tyrosine kinase inhibitors (TKIs) and antibody--drug conjugates (ADCs), has improved the operation rate and pathological remission rate and reduced the risk of postoperative recurrence for HER2- positive early-stage BC (HER2+ EBC) patients. This review systematically summarizes the mechanisms, resistance, therapeutic modalities and safety of HER2-targeted drugs and helps us further understand these drugs and their use in clinical practice for patients with HER2+ EBC. [ABSTRACT FROM AUTHOR]

The first example of sonodynamic therapy (SDT) with a cyanine dye–antibody conjugate is reported. The aim of this study was to evaluate the sonodynamic efficacy of a trastuzumab-guided diiodinated heptamethine cyanine-based sensitizer, 2ICy7–Ab, versus its non-iodinated counterpart, Cy7–Ab, in a human epidermal growth factor receptor 2-positive (HER2+) xenograft model. In addition, the combined sonodynamic and photodynamic (PDT) effects were investigated. A single intravenous injection of 2ICy7–Ab followed by sonication or combined sonication and photoirradiation in mice resulted in complete tumor growth suppression compared with the nontreated control and showed no detectable toxicity to off-target tissues. In contrast, Cy7–Ab provided only a moderate therapeutic effect (~1.4–1.6-fold suppression). SDT with 2ICy7–Ab resulted in a 3.5-fold reduction in tumor volume within 45 days and exhibited 13-fold greater tumor suppression than PDT alone. In addition, 2ICy7–Ab showed more durable sonostability than photostability. The sonotoxicity of the iodinated versus noniodinated counterparts is attributed to the increased generation of hydroxyl radicals, superoxide, and singlet oxygen. We observed no significant contribution of PDT to the efficacy of the combined SDT and PDT, indicating that SDT with 2ICy7–Ab is superior to PDT alone. These new findings set the stage for the application of cyanine–antibody conjugates for fluorescently monitored targeted sonodynamic treatment of cancer. [ABSTRACT FROM AUTHOR]

Background: This study aimed to retrospectively analyse the pathological response and safety of combining albumin-bound paclitaxel (nab-paclitaxel) or docetaxel with anti-HER2 therapy as a neoadjuvant treatment for HER2-positive breast cancer. Methods: From June 2020 to August 2023, 225 HER2-positive breast cancer patients who underwent radical surgery following neoadjuvant treatment were enrolled in this study. The patients were divided into two groups based on the drugs they received: the nab-paclitaxel group (n=166, receiving nab-paclitaxel + platinum along with trastuzumab and pertuzumab) and the docetaxel group (n=59, receiving docetaxel + platinum along with trastuzumab and pertuzumab). The pathological response and adverse events related to the drugs were collected and evaluated in both groups. Results: In the nab-paclitaxel group, the rates of breast and total pathological complete response (bpCR and tpCR) were significantly greater than those in the docetaxel group (69.27% vs. 47.45%, P=0.003; 68.67% vs. 45.76%, P=0.002). For patients who did not achieve pCR after chemotherapy, the pathological response of chemotherapy was analysed using MP grading and RCB grading. The results showed that there was a statistically significant difference between the two groups (P<0.05). Multivariate analysis revealed that therapeutic drugs, clinical stage, ER status, and Ki-67 level were independent predictors of pCR. The nabpaclitaxel group had a significantly greater proportion of patients with peripheral sensory neuropathy than did the docetaxel group (58.43% vs. 38.98%, P=0.035), while the docetaxel group had a greater proportion of patients with allergies and elevated ALT (31.93% vs. 69.49%, P=0.000; 23.49% vs. 40.68%, P=0.021). Conclusions: Our real-world study revealed that nab-paclitaxel combined with anti-HER2 therapy was an effective neoadjuvant therapy for HER2-positive breast cancer. The multivariate analysis revealed that chemotherapy drugs, clinical stage, ER status, and Ki-67 level was the significant factor influencing treatment outcome. These findings offer a valuable reference for the neoadjuvant treatment of patients with HER2-positive breast cancer. [ABSTRACT FROM AUTHOR]

In Mexico, breast cancer (BC) is the principal cause of death in women over 30 years old, with an annual mortality rate of 14.61 deaths per a 100,000 population. Chemotherapy, in combination with trastuzumab (TTZ), improves the survival of cancer patients; however, cardiotoxicity (CT) is the principal consequence. CT prevalence occurs between 10% and 30% of patients; however, there are no data about the prevalence of CT in the Mexican population. This study aims to establish the prevalence of CT in patients treated with anti-HER-2 therapy among BC women in southeast Mexico. A retrospective cross-sectional study was carried out from January 2015 to July 2019. The records of 46 patients diagnosed with HER-2-positive BC who attended the Mexican Social Security Institute in the Ambulatory Care Medicine Unit were analyzed. The diagnostic criterion for CT was a decrease in LVEF > 10% from baseline or a final LVEF < 53%. CT prevalence was observed in 19 (41.3%) of women with cancer, with an average decrease in LVEF of 13%. In the population, we found an association between weight, surface area, and the loading dose of TTZ with CT. Nutritional follow-up and the administration of cardioprotective drugs are necessary to recover LVEF and avoid cardiovascular failure in women with BC and survivors. [ABSTRACT FROM AUTHOR]

Introduction: 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. Methods: 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. Results: Of the 176 recruited, we present data from the first 59 patients (mean age 51.7 ± 12.9 years) who had completed treatment with trastuzumab-dkst. The mean time from diagnosis to the first adjuvant treatment with trastuzumab-dkst was 5.5 ± 2.7 months. 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. Conclusion: 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. ClinicalTrials.gov Registration: NCT03892655. [ABSTRACT FROM AUTHOR]

The irreversible pan‐HER tyrosine kinase inhibitor neratinib is approved for patients with HER2‐positive, early‐stage and metastatic breast cancer (BC). Neratinib‐associated diarrhea is the most common reason for early discontinuation. Preclinical studies identified mechanisms of neratinib‐induced diarrhea and rationale for prophylactic and preventive measures. We studied effects of neratinib on rat intestines and conducted a phase 2 study of colon pathogenesis in patients with HER2‐positive BC treated with neratinib (NCT04366713). Colon samples from female albino Wistar rats receiving neratinib or vehicle were examined for histopathological changes. Patients with HER2‐positive BC received neratinib 240 mg once daily for up to 1 year. Colonoscopy biopsies were collected at baseline and at Day 28 to identify changes consistent with rat pathologies. Rat colons were markedly altered in appearance, with similar short circuit currents (Isc) and responses to carbachol and forskolin. Mucosal barrier loss and/or significant increase in secretory propensity in neratinib‐ versus control‐treated animals were not seen. Two of four endpoint‐evaluable patients presented with mild pathological changes, largely comparable with the rat model. Preclinical evidence supports an inflammatory component of neratinib‐induced diarrhea without mucosal barrier function loss. Colonoscopy findings in patients with BC indicate mild or no pathological changes in the colon due to neratinib treatment. [ABSTRACT FROM AUTHOR]

Objective: Pyrotinib, a new irreversible dual pan-human epidermal growth factor receptor 2 (HER2) receptor tyrosine kinase inhibitor blocking EGFR and HER2, has achieved a promising efficacy for advanced HER2-positive (HER2+) breast cancer. This study intended to further investigate the efficacy and safety of neoadjuvant pyrotinib and trastuzumab plus chemotherapy for HER2+ breast cancer treatment. Methods: Thirty-eight HER2+ breast cancer patients who received neoadjuvant pyrotinib and trastuzumab plus chemotherapy (docetaxel and carboplatin) were retrospectively reviewed. Clinical response by Response Evaluation Criteria in Solid Tumors (RECIST), pathological complete response (pCR), and adverse events data was retrieved. Results: According to the RECIST, the complete response rate was 0.0%, 10.5%, and 15.8% after second-cycle, fourth-cycle, and sixth-cycle therapy, respectively; whereas the objective response rate was 76.3%, 92.1%, and 100.0%, accordingly. The total pCR (tpCR) rate was 52.6%, the pCR rate of the breast was also 52.6%, and the pCR rate of lymph nodes was 86.8%. The tpCR rate was lower in patients with HER2 immunohistochemistry (IHC)++ and amplification by fluorescent in situ hybridization (FISH) than in those with HER2 IHC+++ (14.3% vs. 61.3%, p = 0.024), which was also lower in patients with Ki-67 expression ≥30% than in those with Ki-67 expression <30% (40.0% vs. 76.9%, p = 0.031). The common adverse events included diarrhea (84.2%), anemia (73.7%), nausea and vomiting (63.2%), fatigue (50.0%), hypomagnesemia (44.7%), leukopenia (42.1%), thrombocytopenia (39.5%), elevated transaminase (36.8%), and pruritus (31.6%). Conclusions: Pyrotinib and trastuzumab plus chemotherapy serve as an acceptable neoadjuvant regimen exhibiting good efficacy and tolerance in HER2+ breast cancer patients, while further large-scale validation is warranted. [ABSTRACT FROM AUTHOR]

Background: The current standard of care for advanced human epidermal growth factor receptor 2 (HER2)‐positive breast cancer is pertuzumab plus trastuzumab and docetaxel as first‐line therapy. However, with the development of newer treatment regimens, there is a lack of evidence regarding which is the optimal treatment strategy. The aim of this network meta‐analysis was to evaluate the efficacy and safety of first‐line regimens for advanced HER2‐positive breast cancer by indirect comparisons. Methods: A systematic review and Bayesian network meta‐analysis were conducted. The PubMed, EMBASE, and Cochrane Library databases were searched for relevant articles published through to December 2023. The hazard ratio (HR) and 95% credible interval (CrI) were used to compare progression‐free survival (PFS) between treatments, and the odds ratio and 95% CrI were used to compare the objective response rate (ORR) and safety. Results: Twenty randomized clinical trials that included 15 regimens and 7094 patients were analyzed. Compared with the traditional trastuzumab and docetaxel regimen, PFS was longer on the pyrotinib and trastuzumab plus docetaxel regimen (HR: 0.41, 95% CrI: 0.22–0.75) and the pertuzumab and trastuzumab plus docetaxel regimen (HR: 0.65, 95% CrI: 0.43–0.98). Consistent with the results for PFS, the ORR was better on the pyrotinib and trastuzumab plus docetaxel regimen and the pertuzumab and trastuzumab plus docetaxel regimen than on the traditional trastuzumab and docetaxel regimen. The surface under the cumulative ranking curve indicated that the pyrotinib and trastuzumab plus docetaxel regimen was most likely to rank first in achieving the best PFS and ORR. Comparable results were found for grade ≥3 AE rates of ≥10%. Conclusions: Our results suggest that the pyrotinib and trastuzumab plus docetaxel regimen is most likely to be the optimal first‐line therapy for patients with HER2‐positive breast cancer. [ABSTRACT FROM AUTHOR]

Purpose: Despite previous studies proposing shorter durations of anti-HER2 therapy for selected patients with HER2-positive early breast cancer (EBC), 12-months remains standard of care. A survey was performed to assess patient perspectives and willingness to participate in studies evaluating shorter durations of anti-HER2 therapy. Methods: Patients with HER2-positive EBC completing or having previously completed anti-HER2 therapy, were recruited by healthcare professionals at The Ottawa Hospital Cancer Centre to participate in an anonymous online survey. The primary objective was to learn about patients' perspectives on shorter durations (less than 12-months) of anti-HER2 therapy. Secondary objectives were to explore patients' interest in clinical trials of shorter durations of anti-HER2 therapy and the degree of increased breast cancer risk they would accept with a shorter treatment duration. Results: Responses were received from 94 eligible patients. Most patients received Trastuzumab alone (78%, 73/94), while 13% (12/94) received trastuzumab and pertuzumab. Side effects were experienced by 52% (46/89), the most common being; fatigue (61%, 28/46), myalgia (37%, 17/46), and diarrhea (24%, 11/46). Most patients (88%, 78/89) did not find treatment bothersome. Regarding perspectives on shorter durations of anti-HER2 therapy, most (79%, 74/94) respondents stated they would agree to less treatment if it were possible to receive fewer treatments with the same cancer benefits. 56% of patients were interested in clinical trials, however, about half stated they would not be accepting of any increase in breast cancer recurrence risk. Conclusion: Trials to investigate who can safely and effectively be treated with shorter durations of anti-HER2 therapy are needed. This study provides important insights to patients' perspectives on shorter durations of anti-HER2 treatment, and their concerns regarding potential increased cancer risk with less treatment. [ABSTRACT FROM AUTHOR]

Abstract Background Different hormone receptor (HR) expression patterns have significant biological and therapeutic implications in patients with human epidermal growth factor receptor 2 (HER2)-positive breast cancer. However, the distinction between HR-positive /HER2-positive (HR+/HER2+) and HR-negative/HER2-positive (HR-/HER2+) subtypes remains unclear. Methods This retrospective study analyzed 828 patients with HER2-positive breast cancer at the First Affiliated Hospital of Xi’an Jiaotong University from 2012 to 2022. Baseline characteristics were compared by chi-square test. Survival outcomes were estimated by Kaplan-Meier method. Results In total, 56.3% (n = 466) had HR-positive and 43.7% (n = 362) had HR-negative disease. Comparatively, HR+/HER2 + breast cancers presented favorable clinicopathological features. At a median follow-up of 49 months, 199 disease-free survival (DFS) events and 99 deaths were observed. HR+/HER2 + patients had significantly better survival outcomes than HR-/HER2 + patients. HR-positive status was an independent protective factor for overall survival (OS) [P = 0.032; hazard ratio, 0.61; 95% confidence interval (CI), 0.39–0.96] and DFS (P = 0.001; hazard ratio, 0.61; 95% CI, 0.46–0.81). HR+/HER2 + patients were significantly less sensitive to neoadjuvant therapy than HR-/HER2 + patients. In the first-line treatment for HR+/HER2 + advanced breast cancer, receiving endocrine therapy significantly improved advanced-OS (P

Abstract Background Inetetamab is the first domestically developed innovative anti-HER2 monoclonal antibody in China, proven effective and safe in HER2-positive advanced breast cancer. However, its efficacy and safety in neoadjuvant treatment of HER2-positive locally advanced breast cancer (LABC) remain to be validated. Methods This prospective cohort study aimed to evaluate the efficacy and safety of inetetamab combined with pertuzumab, taxanes, and carboplatin (TCbIP) in neoadjuvant therapy for HER2-positive LABC, comparing it to data from patients treated with the TCbHP regimen (trastuzumab combined with pertuzumab, taxanes, and carboplatin) using propensity score matching (PSM). The primary endpoint was total pathological complete response (tpCR). Adverse events (AEs), objective response rate (ORR), and near-pCR were key secondary endpoints. Results Forty-four patients with clinical stage IIA-IIIC HER2-positive LABC were prospectively enrolled and treated with the TCbIP regimen. The tpCR rate among 28 patients who completed surgery was 60.7%, comparable to and slightly higher than the TCbHP group in PSM (60.7% vs. 53.6%, P = 0.510). The ORR was 96.4%, and the DCR reached 100.0%. The most common ≥ grade 3 AE was neutropenia (21.4% vs. 11.9%, P = 0.350). No significant reduction in left ventricular ejection fraction was observed, and no patient withdrew from treatment due to AEs. Conclusion Neoadjuvant therapy with TCbIP showed good efficacy and safety in patients with HER2-positive LABC and might be another promising option for neoadjuvant treatment. Trial registration NCT05749016 (registration date: Nov 01, 2021).

Abstract Introduction 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. Methods 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. Results Of the 176 recruited, we present data from the first 59 patients (mean age 51.7 ± 12.9 years) who had completed treatment with trastuzumab-dkst. The mean time from diagnosis to the first adjuvant treatment with trastuzumab-dkst was 5.5 ± 2.7 months. 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. Conclusion 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. ClinicalTrials.gov Registration NCT03892655.

Abstract 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

Abstract Introduction Breast cancer ranks second as the most common malignancy globally, after lung cancer. Among the various subtypes of breast cancer, HER2 positive breast cancer (HER2 BC)poses a particularly challenging prognosis due to its heightened invasiveness and metastatic potential. The objective of this study was to construct a composite piezoelectric nanoparticle based on poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) for imaging and treatment of HER2 BC. Method By reshaping the crystal structure of P(VDF-TrFE) piezoelectric nanoparticles, improving hydrophilicity, and incorporating imaging capabilities, we developed piezoelectric composite nanoparticles (PGd@tNBs) that integrate imaging and therapeutic functions. The in vitro characterization encompassed the assessment of piezoelectric properties, hydrophilicity, imaging performance, and therapeutic efficacy of these particles. The targeting and therapeutic effectiveness of PGd@tNBs particles were further validated in the SK-BR3 cell line and subsequently confirmed in HER2-positive tumor-bearing mice. Results The nanoparticle demonstrated excellent biocompatibility and impressive multimodal imaging performance. Magnetic resonance imaging (MRI) observations revealed significant accumulation of PGd@tNBs particles in the HER2 positive tumor, exhibiting superior contrast-enhanced ultrasound performance compared to traditional ultrasound contrast agents, and small animal in vivo imaging showed that PGd@tNBs particles were primarily excreted through respiration and urinary metabolism. Piezoforce Microscopy characterization highlighted the outstanding piezoelectric properties of PGd@tNBs particles. Upon targeted binding to HER2-BC, ultrasound stimulation influenced the cell membrane potential, leading to reversible electroporation. This, in turn, affected the balance of calcium ions inside and outside the cells and the mitochondrial membrane potential. Following ingestion by cells, PGd@tNBs, when exposed to ultrasound, triggered the generation of reactive oxygen species (ROS), resulting in the consumption of glutathione and superoxide dismutase and achieving sonodynamic therapy. Notably, repeated ultrasound stimulation, post PGd@tNBs particles binding and entry into cells, increased ROS production and elevated the apoptosis rate by approximately 45%. Conclusion In conclusion, the PGd@tNBs particles developed exhibit outstanding imaging and therapeutic efficacy, holding potential for precise diagnosis and personalized treatment of HER2 BC.

Abstract In this study, we prepared a bionic nanosystem of trastuzumab-functionalized SK-BR-3 cell membrane hybrid liposome-coated pyrotinib (Ptb-M-Lip-Her) for the treatment of HER2-positive breast cancer. Transmission electron microscopy, dynamic light scattering, polyacrylamide gel electrophoresis (SDS-PAGE) and western blotting were used to verify the successful preparation of Ptb-M-Lip-Her. In vitro drug release experiments proved that Ptb-M-Lip-Her had a sustained release effect. Cell uptake experiments and in vivo imaging experiments proved that Ptb-M-Lip-Her had good targeting ability to homologous tumor cells (SK-BR-3). The results of cell experiments such as MTT, flow cytometry, immunofluorescence staining and in vivo antitumor experiments showed that Ptb-M-Lip-Her could significantly promote apoptosis and inhibit the proliferation of SK-BR-3 cells. These results clearly indicated that Ptb-M-Lip-Her may be a promising biomimetic nanosystem for targeted therapy of HER2-positive breast cancer.

Background: Inetetamab is the first domestically developed innovative anti-HER2 monoclonal antibody in China, proven effective and safe in HER2-positive advanced breast cancer. However, its efficacy and safety in neoadjuvant treatment of HER2-positive locally advanced breast cancer (LABC) remain to be validated. Methods: This prospective cohort study aimed to evaluate the efficacy and safety of inetetamab combined with pertuzumab, taxanes, and carboplatin (TCbIP) in neoadjuvant therapy for HER2-positive LABC, comparing it to data from patients treated with the TCbHP regimen (trastuzumab combined with pertuzumab, taxanes, and carboplatin) using propensity score matching (PSM). The primary endpoint was total pathological complete response (tpCR). Adverse events (AEs), objective response rate (ORR), and near-pCR were key secondary endpoints. Results: Forty-four patients with clinical stage IIA-IIIC HER2-positive LABC were prospectively enrolled and treated with the TCbIP regimen. The tpCR rate among 28 patients who completed surgery was 60.7%, comparable to and slightly higher than the TCbHP group in PSM (60.7% vs. 53.6%, P = 0.510). The ORR was 96.4%, and the DCR reached 100.0%. The most common ≥ grade 3 AE was neutropenia (21.4% vs. 11.9%, P = 0.350). No significant reduction in left ventricular ejection fraction was observed, and no patient withdrew from treatment due to AEs. Conclusion: Neoadjuvant therapy with TCbIP showed good efficacy and safety in patients with HER2-positive LABC and might be another promising option for neoadjuvant treatment. Trial registration: NCT05749016 (registration date: Nov 01, 2021). [ABSTRACT FROM AUTHOR]

Background: This study aims to compare treatment outcomes in patients with Triple-Negative Breast Cancer (TNBC) and HER2-Positive Breast Cancer, evaluating clinical responses, survival rates, recurrence rates, quality of life (QoL), and adverse events. Materials and Methods: A total of 100 female patients were included, with 50 diagnosed with TNBC and 50 with HER2-Positive Breast Cancer. Data on demographics, treatment regimens, clinical outcomes, survival rates, recurrence rates, QoL scores, and adverse events were collected and analyzed. Results: Mean age was 52.3 ± 9.7 years for TNBC and 54.1 ± 10.2 years for HER2-Positive patients. Surgery was performed in 90% of TNBC and 85% of HER2-Positive patients. Chemotherapy was administered to all patients. Radiation therapy was given to 60% of TNBC and 65% of HER2-Positive patients. Targeted therapy was administered to 10% of TNBC and 95% of HER2-Positive patients. Complete response rates were 20% for TNBC and 35% for HER2-Positive patients. Partial response rates were 40% for TNBC and 45% for HER2-Positive patients. Progressive disease occurred in 15% of TNBC and 10% of HER2-Positive patients. Survival rates at various time points are provided in Table 4. The 1-year overall survival (OS) rate was 80% (40 patients) for TNBC and 90% (45 patients) for HER2-Positive patients. The 2-year OS was 60% (30 patients) for TNBC and 75% (38 patients) for HER2- Positive patients. Local recurrence was 30% for TNBC and 20% for HER2- Positive patients. Distant metastasis occurred in 40% of TNBC and 25% of HER2-Positive patients. Grade 3-4 neutropenia was reported in 25% of TNBC and 20% of HER2-Positive patients. Cardiotoxicity was observed in 5% of TNBC and 10% of HER2-Positive patients. Conclusion: HER2-Positive patients exhibited better clinical outcomes and survival rates than TNBC patients but had a higher incidence of cardiotoxicity. These findings underscore the need for tailored treatment approaches and vigilant monitoring of adverse events. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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 [ABSTRACT FROM AUTHOR]

Introduction: Breast cancer ranks second as the most common malignancy globally, after lung cancer. Among the various subtypes of breast cancer, HER2 positive breast cancer (HER2 BC)poses a particularly challenging prognosis due to its heightened invasiveness and metastatic potential. The objective of this study was to construct a composite piezoelectric nanoparticle based on poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) for imaging and treatment of HER2 BC. Method: By reshaping the crystal structure of P(VDF-TrFE) piezoelectric nanoparticles, improving hydrophilicity, and incorporating imaging capabilities, we developed piezoelectric composite nanoparticles (PGd@tNBs) that integrate imaging and therapeutic functions. The in vitro characterization encompassed the assessment of piezoelectric properties, hydrophilicity, imaging performance, and therapeutic efficacy of these particles. The targeting and therapeutic effectiveness of PGd@tNBs particles were further validated in the SK-BR3 cell line and subsequently confirmed in HER2-positive tumor-bearing mice. Results: The nanoparticle demonstrated excellent biocompatibility and impressive multimodal imaging performance. Magnetic resonance imaging (MRI) observations revealed significant accumulation of PGd@tNBs particles in the HER2 positive tumor, exhibiting superior contrast-enhanced ultrasound performance compared to traditional ultrasound contrast agents, and small animal in vivo imaging showed that PGd@tNBs particles were primarily excreted through respiration and urinary metabolism. Piezoforce Microscopy characterization highlighted the outstanding piezoelectric properties of PGd@tNBs particles. Upon targeted binding to HER2-BC, ultrasound stimulation influenced the cell membrane potential, leading to reversible electroporation. This, in turn, affected the balance of calcium ions inside and outside the cells and the mitochondrial membrane potential. Following ingestion by cells, PGd@tNBs, when exposed to ultrasound, triggered the generation of reactive oxygen species (ROS), resulting in the consumption of glutathione and superoxide dismutase and achieving sonodynamic therapy. Notably, repeated ultrasound stimulation, post PGd@tNBs particles binding and entry into cells, increased ROS production and elevated the apoptosis rate by approximately 45%. Conclusion: In conclusion, the PGd@tNBs particles developed exhibit outstanding imaging and therapeutic efficacy, holding potential for precise diagnosis and personalized treatment of HER2 BC. [ABSTRACT FROM AUTHOR]

In this study, we prepared a bionic nanosystem of trastuzumab-functionalized SK-BR-3 cell membrane hybrid liposome-coated pyrotinib (Ptb-M-Lip-Her) for the treatment of HER2-positive breast cancer. Transmission electron microscopy, dynamic light scattering, polyacrylamide gel electrophoresis (SDS-PAGE) and western blotting were used to verify the successful preparation of Ptb-M-Lip-Her. In vitro drug release experiments proved that Ptb-M-Lip-Her had a sustained release effect. Cell uptake experiments and in vivo imaging experiments proved that Ptb-M-Lip-Her had good targeting ability to homologous tumor cells (SK-BR-3). The results of cell experiments such as MTT, flow cytometry, immunofluorescence staining and in vivo antitumor experiments showed that Ptb-M-Lip-Her could significantly promote apoptosis and inhibit the proliferation of SK-BR-3 cells. These results clearly indicated that Ptb-M-Lip-Her may be a promising biomimetic nanosystem for targeted therapy of HER2-positive breast cancer. [ABSTRACT FROM AUTHOR]

Simple Summary: HER2-positive breast cancer, treated with trastuzumab, often develops resistance within a year in about 50% of patients. This study identifies ITGβ3 as a key factor in promoting resistance by upregulating stem cell markers through the Notch signaling pathway. Combining trastuzumab with the integrin inhibitor cilengitide significantly reduces these markers, suggesting a potential therapeutic approach to overcoming resistance. HER2-positive breast cancer, characterised by overexpressed HER2 levels, is associated with aggressive tumour behaviour and poor prognosis. Trastuzumab is a standard treatment; however, approximately 50% of patients develop resistance within one year. This study investigates the role of ITGβ3 in promoting stemness and resistance in HER2-positive breast cancer cell lines (HCC1599 and SKBR3). The findings demonstrate that chronic exposure to trastuzumab upregulates stem cell markers (SOX2, OCT4, KLF4, NANOG, SALL4, ALDH, BMI1, Nestin, Musashi 1, TIM3, CXCR4). Given the documented role of RGD-binding integrins in drug resistance and stemness, we specifically investigated their impact on resistant cells. Overexpression of ITGβ3 enhances the expression of these stem cell markers, while silencing ITGβ3 reduces their expression, suggesting a major role for ITGβ3 in maintaining stemness and resistance. Further analysis reveals that ITGβ3 activates the Notch signalling pathway, known for regulating stem cell maintenance. The combination of trastuzumab and cilengitide, an integrin inhibitor, significantly decreases the expression of stem cell markers in resistant cells, indicating a potential therapeutic strategy to overcome resistance. These results identify the importance of ITGβ3 in mediating stemness and trastuzumab resistance through Notch signalling in HER2-positive breast cancer, offering new approaches for enhancing treatment efficacy. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the imaging and therapeutic properties (theranostic) of 67Cu-labeled anti-human epidermal growth factor receptor II (HER2) monoclonal antibody trastuzumab against HER2-positive breast cancer (BC). Methods: We conjugated trastuzumab with p-SCN-Bn-NOTA, 3p-C-NETA-NCS, or p-SCN-Bn-DOTA, and radiolabeled with [67Cu]CuCl2. Immunoconjugate internalization was evaluated in BT-474, JIMT-1 and MCF-7 BC cells. In vitro stability was studied in human serum (HS) and Phosphate Buffered Saline (PBS). Flow cytometry, radioligand binding and immunoreactive fraction assays were carried out. ImmunoSPECT imaging of [67Cu]Cu-NOTA-trastuzumab was done in mice bearing BT-474, JIMT-1 and MCF-7 xenografts. Pharmacokinetic was studied in healthy Balb/c mice while dosimetry was done in both healthy Balb/c and in athymic nude mice bearing JIMT-1 xenograft. The therapeutic effectiveness of [67Cu]Cu-NOTA-trastuzumab was evaluated in mice bearing BT-474 and JIMT-1 xenografts after a single intravenous (i.v.) injection of ~ 16.8 MBq. Results: Pure immunoconjugates and radioimmunoconjugates (> 95%) were obtained. Internalization was HER2 density-dependent with highest internalization observed with NOTA-trastuzumab. After 5 days, in vitro stabilities were 97 ± 1.7%, 31 ± 6.2%, and 28 ± 4% in HS, and 79 ± 3.5%, 94 ± 1.2%, and 86 ± 2.3% in PBS for [67Cu]Cu-NOTA-trastuzumab, [67Cu]Cu-3p-C-NETA-trastuzumab and [67Cu]Cu-DOTA-trastuzumab, respectively. [67Cu]Cu-NOTA-trastuzumab was chosen for further evaluation. BT-474 flow cytometry showed low KD, 8.2 ± 0.2 nM for trastuzumab vs 26.5 ± 1.6 nM for NOTA-trastuzumab. There were 2.9 NOTA molecules per trastuzumab molecule. Radioligand binding assay showed a low KD of 2.1 ± 0.4 nM and immunoreactive fraction of 69.3 ± 0.9. Highest uptake of [67Cu]Cu-NOTA-trastuzumab was observed in JIMT-1 (33.9 ± 5.5% IA/g) and BT-474 (33.1 ± 10.6% IA/g) xenograft at 120 h post injection (p.i.). Effectiveness of the radioimmunoconjugate was also expressed as percent tumor growth inhibition (%TGI). [67Cu]Cu-NOTA-trastuzumab was more effective than trastuzumab against BT-474 xenografts (78% vs 54% TGI after 28 days), and JIMT-1 xenografts (90% vs 23% TGI after 19 days). Mean survival of [67Cu]Cu-NOTA-trastuzumab, trastuzumab and saline treated groups were > 90, 77 and 72 days for BT-474 xenografts, while that of JIMT-1 were 78, 24, and 20 days, respectively. Conclusion: [67Cu]Cu-NOTA-trastuzumab is a promising theranostic agent against HER2-positive BC. [ABSTRACT FROM AUTHOR]

Introduction: Cancer diagnosis influences the choices that patients make regarding current and future labor market activity. These choices have implications for governments based on resulting changes in taxes paid and benefits received. In this analysis we explore how human growth receptor 2 (HER2)-positive residual invasive breast cancer and different treatments influence government accounts excluding health costs. Methods: HER2-positive early breast cancer (eBC) health states from a published disease model were used to establish likelihood of working and wage impact at different stages of disease. The indirect productivity losses for an average woman aged 49 years were translated into fiscal consequences to government by applying an established government perspective-modeling framework. The fiscal projections (discounted) include gross tax revenue by disease stage, government transfer costs related to time off work and early retirement ,and net fiscal balance (e.g., gross taxes—transfers) in three countries Canada, Portugal, and Brazil. Results: The net fiscal balance in Canada for a healthy woman was C$109,551 compared with a HER2-positive eBC woman treated with trastuzumab emtansine (C$69,767) or trastuzumab (C$62,971). A similar pattern was observed in the three countries but reflecting the overall tax burden in each country, labor force activity, and available public benefits. Age at diagnosis was an important determinant of the likely net fiscal balance, as this influences the remaining working years. Discussion: Women diagnosed with HER2-positive eBC were estimated to pay less lifetime gross taxes and receive more in sickness benefits compared with healthy women. Treatments that improve outcomes are likely to offer fiscal gains for government from improved work force participation. [ABSTRACT FROM AUTHOR]

Simple Summary: Metabolic reprogramming in HER2-positive breast cancer is associated with acquired resistance to targeted therapies. Thus, targeting dysregulated metabolic pathways in cancers is highly beneficial. In this study, we examined the anti-tumor effects of an LXR inverse agonist GAC0001E5 (1E5) in HER2-positive breast cancer in vitro. Strikingly, we observed disruption of two major pathways, glutaminolysis and de novo lipogenesis, leading to oxidative stress and cell death. Additionally, we discovered the indirect effects of 1E5 in downregulating HER2 expression through fatty acid synthase (FASN). Moreover, in combinatory treatments of 1E5 and lapatinib, 1E5 potentiates lapatinib's effects. These findings indicate the importance of 1E5 as a metabolic disruptor in HER2-positive breast cancer. The HER2-positive subtype accounts for approximately one-fifth of all breast cancers. Insensitivity and development of acquired resistance to targeted therapies in some patients contribute to their poor prognosis. HER2 overexpression is associated with metabolic reprogramming, facilitating cancer cell growth and survival. Novel liver X receptor (LXR) ligand GAC0001E5 (1E5) has been shown to inhibit cancer cell proliferation by disrupting glutaminolysis and inducing oxidative stress. In this study, HER2-positive breast cancer cells were treated with 1E5 to determine their potential inhibitory effects and mechanisms of action in HER2-positive breast cancers. Similar to previous observations in other cancer types, 1E5 treatments inhibited LXR activity, expression, and cancer cell proliferation. Expression of fatty acid synthesis genes, including fatty acid synthase (FASN), was downregulated following 1E5 treatment, and results from co-treatment experiments with an FASN inhibitor suggest that the same pathway is targeted by 1E5. Treatments with 1E5 disrupted glutaminolysis and resulted in increased oxidative stress. Strikingly, HER2 transcript and protein levels were both significantly downregulated by 1E5. Taken together, these findings indicate the therapeutic potential of targeting HER2 overexpression and associated metabolic reprogramming via the modulation of LXR in HER2-positive breast cancers. [ABSTRACT FROM AUTHOR]

Introduction. HER2-positive breast cancer represents 10-20% of all breast tumors. This study aimed to create a model-based cost-minimization analysis that compared non-drug related costs of different therapies used in the treatment of HER2-positive breast cancer in Poland: pertuzumab SC plus trastuzumab SC (Pert/TrasSC) vs. pertuzumab IV plus trastuzumab IV (PertIV + TrasIV) vs. pertuzumab IV plus trastuzumab SC (PertIV + TrasSC). Material and methods. The cost-minimization analysis was based on the results of a questionnaire addressed to leading oncology centers in Poland. The model was broken down into three categories of cost savings: reduced labor costs of nurses, pharmacists and non-drug related consumables, and from two categories of treatment time reduction: occupation of infusion chair and duration of hospital stay. Data on resources used and costs were collected in the first half of 2022. Results. Data were obtained from four oncology centers. The savings generated per patient from healthcare personnel's work and from non-drug consumables for the Pert/TrasSC arm were 178 PLN compared to PertIV + TrasIV and 168 PLN compared to PertIV + TrasSC. Full adaptation of Pert/TrasSC was estimated to result in average 8-fold higher savings in healthcare personnel workload per patient and in a treatment capacity increase of 241 patients. Conclusions. Our model shows that Pert/TrasSC treatment is associated with significantly lower labor costs for nurses and pharmacists and lower costs of non-drug consumables compared to the other treatment options. Moreover, it reduced patients' chair time due to shorter administration/observation time and released capacity in chemotherapy infusion sites. [ABSTRACT FROM AUTHOR]

Trastuzumab (T) and tyrosine kinase inhibitors (TKIs) are among the first-line treatments recommended for HER2-positive breast cancer. More recently, antibody-drug conjugates (ADCs) such as trastuzumab deruxtecan (T-DXd) and trastuzumab emtansine (T-DM1) have been authorized, and they represent the second-line therapy in this type of cancer. The present study aimed to evaluate adverse drug reactions (ADRs) associated with T-based ADCs that were spontaneously reported in EudraVigilance—the European pharmacovigilance database. Out of 42,272 ADRs reported for currently approved ADCs on the market, 24% of ADRs were related to T-DM1, while 12% of ADRs were related to T-DXd. T-DM1 had a higher probability of reporting eye, ear and labyrinth, and cardiac and hepatobiliary ADRs, while T-DXd had a higher probability of reporting respiratory, thoracic and mediastinal, blood and lymphatic system, metabolism and nutrition, and gastrointestinal ADRs. The present research found that in terms of hematological disorders, T-DM1 and T-DXd had a higher probability of reporting ADRs than TKIs. Moreover, the data showed that T-DM1 seemed to have a higher risk of cardiotoxicity than T-DXd, while T-DXd had a higher probability of reporting metabolism and nutrition disorders than T-DM1. [ABSTRACT FROM AUTHOR]

Trastuzumab has improved survival rates in human epidermal growth factor receptor 2 (HER2)-positive breast cancer (BC), but drug resistance leads to treatment failure. Natural killer (NK) cell-mediated antibody-dependent cell cytotoxicity (ADCC) represents an essential antitumor immune mechanism of trastuzumab. Traditional Chinese medicine (TCM) has been used for centuries to treat diseases because of its capacity to improve immune responses. Xianling Lianxia formula (XLLXF), based on the principle of “strengthening body and eliminating toxin”, exhibits a synergistic effect in the trastuzumab treatment of patients with HER2-positive BC. Notably, this synergistic effect of XLLXF was executed by enhancing NK cells and ADCC, as demonstrated through in vitro co-culture of NK cells and BC cells and in vivo intervention experiments. Mechanistically, the augmented impact of XLLXF on NK cells is linked to a decrease in cytokine inducible Src homology 2 (SH2) containing protein (CISH) expression, which in turn activates the Janus kinase 1 (JAK1)/signal transducer and activator of transcription 5 (STAT5) pathway. Collectively, these findings suggested that XLLXF holds promise for enhancing NK cell function and sensitizing patients with HER2-positive BC to trastuzumab.

Despite the approval of several therapeutic agents for HER2-positive breast cancer, drug resistance remains a significant challenge, hindering the patient's prognosis. Thus, our study aimed to establish a risk model to predict the prognosis of patients and identify key genes regulating drug resistance in HER2-positive breast cancer. Utilizing data from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO), a predictive model was constructed based on 5 drug resistance-related genes, which demonstrated a notable capacity to indicate the survival rates of patients. Besides, through eccDNA and transcriptome sequencing of drug-sensitive and resistant cancer cells, 3 significant DEGs were identified: MED1, MED24, and NMD3. Among them, MED1 showed the most significant elevation in drug-resistance cells, highlighting its crucial role in mediating drug resistance. MED1 may serve as a valuable target for alleviating drug resistance in HER2-positive breast cancer.

Abstract The irreversible pan‐HER tyrosine kinase inhibitor neratinib is approved for patients with HER2‐positive, early‐stage and metastatic breast cancer (BC). Neratinib‐associated diarrhea is the most common reason for early discontinuation. Preclinical studies identified mechanisms of neratinib‐induced diarrhea and rationale for prophylactic and preventive measures. We studied effects of neratinib on rat intestines and conducted a phase 2 study of colon pathogenesis in patients with HER2‐positive BC treated with neratinib (NCT04366713). Colon samples from female albino Wistar rats receiving neratinib or vehicle were examined for histopathological changes. Patients with HER2‐positive BC received neratinib 240 mg once daily for up to 1 year. Colonoscopy biopsies were collected at baseline and at Day 28 to identify changes consistent with rat pathologies. Rat colons were markedly altered in appearance, with similar short circuit currents (Isc) and responses to carbachol and forskolin. Mucosal barrier loss and/or significant increase in secretory propensity in neratinib‐ versus control‐treated animals were not seen. Two of four endpoint‐evaluable patients presented with mild pathological changes, largely comparable with the rat model. Preclinical evidence supports an inflammatory component of neratinib‐induced diarrhea without mucosal barrier function loss. Colonoscopy findings in patients with BC indicate mild or no pathological changes in the colon due to neratinib treatment.

Abstract Background Recent investigations have reported the benefits of using a tyrosine kinase inhibitor, dasatinib (DA), as well as programmed death-ligand 1 (PD-L1) inhibitors in the management of several solid tumors, including breast cancer. Nevertheless, the outcome of the combination of these inhibitors on HER2-positive breast cancer is not explored yet. Methods Herein, we investigated the impact of DA and PD-L1 inhibitor (BMS-202) combination on HER2-positive breast cancer cell lines, SKBR3 and ZR75. Results Our data reveal that the combination significantly inhibits cell viability of both cancer cell lines as compared to monotreatment. Moreover, the combination inhibits epithelial-mesenchymal transition (EMT) progression and reduces cancer cell invasion by restoring E-cadherin and β-catenin expressions and loss of vimentin, major biomarkers of EMT. Additionally, the combination reduces the colony formation of both cell lines in comparison with their matched control. Also, the combination considerably inhibits the angiogenesis of the chorioallantoic membrane model compared with monotreatment. Molecular pathway analysis of treated cells shows that this combination blocks HER2, AKT, β-catenin, and JNK1/2/3 activities. Conclusion Our findings implicate that a combination of DA and BMS-202 could have a significant impact on the management of HER2-positive breast cancer.

Abstract Introduction Cancer diagnosis influences the choices that patients make regarding current and future labor market activity. These choices have implications for governments based on resulting changes in taxes paid and benefits received. In this analysis we explore how human growth receptor 2 (HER2)-positive residual invasive breast cancer and different treatments influence government accounts excluding health costs. Methods HER2-positive early breast cancer (eBC) health states from a published disease model were used to establish likelihood of working and wage impact at different stages of disease. The indirect productivity losses for an average woman aged 49 years were translated into fiscal consequences to government by applying an established government perspective-modeling framework. The fiscal projections (discounted) include gross tax revenue by disease stage, government transfer costs related to time off work and early retirement ,and net fiscal balance (e.g., gross taxes—transfers) in three countries Canada, Portugal, and Brazil. Results The net fiscal balance in Canada for a healthy woman was C$109,551 compared with a HER2-positive eBC woman treated with trastuzumab emtansine (C$69,767) or trastuzumab (C$62,971). A similar pattern was observed in the three countries but reflecting the overall tax burden in each country, labor force activity, and available public benefits. Age at diagnosis was an important determinant of the likely net fiscal balance, as this influences the remaining working years. Discussion Women diagnosed with HER2-positive eBC were estimated to pay less lifetime gross taxes and receive more in sickness benefits compared with healthy women. Treatments that improve outcomes are likely to offer fiscal gains for government from improved work force participation.

Human epidermal growth factor receptor 2 (HER2)-positive breast cancer (BC) is characterized by high invasiveness. Trastuzumab considerably improves the prognoses of HER2-positive BC, but some patients exhibit drug resistance. In this study, the effects of XLLXF combined with trastuzumab on the proliferation, apoptosis, invasion, and migration of HER2-positive BC cells are evaluated, and network pharmacology is performed. Then, we conduct an in vivo study using a xenograft mouse model of HER2-positive BC, and tumor growth is monitored. The expression levels of cytokines are measured by ELISA. Molecular docking is performed to observe the binding stability of IL2, JAK, STAT, and TNF with curcumenol, icariside-II, lobetyolin, and scutellarein. Finally, we observe changes in JAK1 and TNF-α in tumor tissues by immunohistochemistry. The results show that XLLXF enhances the inhibitory effects of trastuzumab on the proliferation, colony formation ability, migration, and invasion of HER2-positive BC cells and promotes apoptosis. Network pharmacology reveals that XLLXF may exert its effects on HER2-positive BC by modulating pathways such as the ErbB, JAK-STAT, and NF-κB pathways. Potential targets include cytokines closely related to immune function. In the in vivo study, XLLXF synergistically enhances the inhibitory effects of trastuzumab on tumor growth. ELISA reveals that XLLXF combined with trastuzumab increases the levels of IL-15, IL-2, TNF-α, and IFN-γ in tumor-bearing mice. Immunohistochemistry confirms that XLLXF can regulate the expressions of JAK1 and TNF-α. This study demonstrates that XLLXF can synergistically enhance the efficacy of trastuzumab in targeting HER2-positive BC. The mechanism may involve the modulation of inflammatory factors.

Summary: Background: The PHILA study suggests that pyrotinib, trastuzumab, and docetaxel significantly improved progression-free survival (PFS) compared with placebo, trastuzumab, and docetaxel in patients with untreated HER2-positive metastatic breast cancer. In this study, we aimed to investigate the synergistic mechanisms of pyrotinib plus trastuzumab and provide further insights for the PHILA trial. Methods: The in vitro activity of combination treatments was assessed through cell biological and biochemical experiments. The in vivo efficacy was evaluated in cell-derived xenografts, a TUBO tumour model, and one clinical case. Next-generation sequencing was performed on circulating tumour DNA (ctDNA) from patients in the PHILA trial. Findings: The combination of pyrotinib and trastuzumab more effectively inhibited cell growth than pyrotinib or trastuzumab alone in models of HER2-dependent breast cancer. It potentiated membrane HER2 ubiquitination and downregulation, which resulted in a comprehensive blockade of the HER2 signalling pathway. The pyrotinib-altered membrane HER2 levels had no significant effect on trastuzumab-mediated antibody-dependent cell-mediated cytotoxicity (ADCC). We further validated the synergistic mechanisms in TUBO tumours and one clinical case, rather than models of HCC1954 cells harbouring the PIK3CA H1047R mutation. Similarly, in our centre cohort of the PHILA study, patients with genetic alterations in the HER2 signalling cascade had significantly shorter median PFS than individuals with the wild-type pathway. Interpretation: Our findings underscore the robust synergy between pyrotinib and trastuzumab in overcoming HER2 dependency and provide a rationale for pyrotinib, trastuzumab, and docetaxel as one of the optimal choices for patients with untreated HER2-positive metastatic breast cancer, who are dependent on the HER2 signalling cascade. Funding: This work was supported by the National Key Research and Development Program of China (2021YFF1201300), the National Natural Science Foundation of China (82172875), the CAMS Innovation Fund for Medical Sciences (CIFMS) (2022-I2M-2-001), and the Joint Innovative Fund of Beijing Natural Science Foundation and Changping District (L234004).

BackgroundKRISTINE is an open-label, phase III study of trastuzumab emtansine + pertuzumab (T-DM1 + P) versus docetaxel + carboplatin + trastuzumab + pertuzumab (TCH + P) in patients with HER2-positive, stage II-III breast cancer. We investigated the association of biomarkers with clinical outcomes in KRISTINE.MethodsPatients were randomized to receive neoadjuvant T-DM1 + P or TCH + P and assessed for pathologic complete response (pCR; ypT0/is, ypN0). HER2 status (per central assessment), hormone receptor status, PIK3CA mutation status, HER2/HER3 mRNA levels, tumor-infiltrating lymphocyte levels, PD-L1 status, and NanoString data were analyzed. pCR rates by treatment arm were compared across biomarker subgroups. Analyses were descriptive.ResultsBiomarker analyses included data from all 444 patients (T-DM1 + P, n = 223; TCH + P, n = 221) enrolled in KRISTINE. Biomarker distribution was balanced across treatment arms. All subgroups with higher HER2 amplification/expression and immune marker levels showed numerically higher pCR rates in both arms. Mutated versus non-mutated PIK3CA tumors were associated with numerically lower pCR rates in the T-DM1 + P arm but not in the TCH + P arm. In a multivariate analysis, Prediction Analysis of Microarray with the 50-gene classifier (PAM50) HER2-enriched subtype, HER2 gene ratio ≥ 4, and PD-L1-positive status positively influenced the pCR rate. Biomarkers associated with lower pCR rates (e.g., low HER2 levels, positive hormone receptor status, mutated PIK3CA) were more likely to co-occur. Dynamic on-treatment biomarker changes were observed. Differences in the treatment effects for T-DM1 + P versus TCH + P were similar to those observed in the intent-to-treat population for the majority of the biomarker subgroups.ConclusionsAlthough our biomarker analysis did not identify a subgroup of patients that benefited from neoadjuvant T-DM1 + P versus TCH + P, the data revealed that patients with higher HER2 amplification/expression and immune marker levels had improved response irrespective of treatment arm. These analyses confirm the role of HER2 tumor biology and the immune microenvironment in influencing pCR in the neoadjuvant setting and reaffirm the molecular diversity of HER2-positive breast cancer.Trial registrationClinicalTrials.gov NCT02131064. Registered 06 May 2014.

Anti‐HER2 (human epidermal growth factor receptor 2) therapies significantly increase the overall survival of patients with HER2‐positive breast cancer. Unfortunately, a large fraction of patients may develop primary or acquired resistance. Further, a multidrug combination used to prevent this in the clinic places a significant burden on patients. To address this issue, this work develops a nanotherapeutic platform that incorporates bimetallic gold‐silver hollow nanoshells (AuAg HNSs) with exceptional near‐infrared (NIR) absorption capability, the small‐molecule tyrosine kinase inhibitor pyrotinib (PYR), and Herceptin (HCT). This platform realizes targeted delivery of multiple therapeutic effects, including chemo‐and photothermal activities, oxidative stress, and immune response. In vitro assays reveal that the HCT‐modified nanoparticles exhibit specific recognition ability and effective internalization by cells. The released PYR inhibit cell proliferation by downregulating HER2 and its associated pathways. NIR laser application induces a photothermal effect and tumor cell apoptosis, whereas an intracellular reactive oxygen species burst amplifies oxidative stress and triggers cancer cell ferroptosis. Importantly, this multimodal therapy also promotes the upregulation of genes related to TNF and NF‐κB signaling pathways, enhancing immune activation and immunogenic cell death. In vivo studies confirm a significant reduction in tumor volume after treatment, substantiating the potential effectiveness of these nanocarriers. [ABSTRACT FROM AUTHOR]

Aim: Trastuzumab-anns is an intravenously administered biosimilar to trastuzumab approved by the EMA and US FDA for treatment of HER2+ early and metastatic breast cancer as well as metastatic gastric cancer. Lack of real-world characterization of biosimilar use has hindered uptake. Methods: This observational chart review characterizes 488 patients who received trastuzumab-anns in EU clinical practice settings. Results: Approximately 2/3rds of patients initiated trastuzumab-anns in adjuvant and neoadjuvant settings and most were naive new starters (70%). 30% were switchers from another trastuzumab, among whom 48% switched from trastuzumab iv. reference product. Common reasons for trastuzumab-anns discontinuation were a switch to another biosimilar product (34.8%, n = 85) or to trastuzumab reference product (15.6%, n = 38). Conclusion: Trastuzumab-anns was widely used in various treatment settings for HER2+ breast cancer. Some patients have a type of breast cancer caused by abnormal amounts of a normal growth factor receptor. This growth factor receptor, known as human epidermal growth factor receptor-2 (HER-2), plays a role in normal life changes that occur in breast tissue, including during pregnancy. HER-2 exists on the surface of breast cells and sends a signal inside cells for growth and proliferation. Sometimes an abnormal amount of HER-2 appears on breast cell surfaces, which causes HER-2 to promote excessive growth and proliferation and leads to HER2+ breast cancer. HER2+ breast cancer can be treated with trastuzumab, a medicine that specifically blocks HER-2 signals, and stops cancer cell growth. Trastuzumab has greatly improved outcomes for women worldwide with HER2+ breast cancer but trastuzumab is not always available due, in part, to its high cost. Biosimilars are medicines that are highly similar, but not identical, to the brand name (original) product and have been shown in clinical trials to result in no meaningful difference in efficacy and safety compared with the original product. Trastuzumab-anns is an intravenously administered biosimilar to trastuzumab. Biosimilars are as effective and safe as original products, although more cost-effective, such that physicians and patients can benefit from more information about their use in the real world. This study provided information about trastuzumab-anns use from clinical oncology practices in seven European countries. The study provides real world evidence that trastuzumab-anns is used widely across different patients with HER2+ breast cancer, including those with metastatic disease. [ABSTRACT FROM AUTHOR]

Cell-penetrating peptides (CPPs) are invaluable tools for delivering various substances into cells by crossing biological membranes. However, the effects of cell-penetrating peptide fusion proteins on the biological activity of antibodies remain to be fully understood. Here, we engineered a recombinant protein, LP-scFv, which combines the single-chain variable region of anti-human epidermal growth factor receptor-2 with a novel and non-oxic cell-penetrating peptide as a leader peptide. The introduction of this leader peptide led to a more than twofold increase in the internalization efficiency of the single-chain antibody, as confirmed using microscopic analysis and flow cytometry. The effects of the single-chain antibodies and LP-scFv on cell viability were evaluated using the MTT assay. Both the single-chain antibodies and LP-scFv reduced the viability of BT474 and NCI-N87 cells in a dose-dependent manner while exhibiting minimal toxicity towards MCF-7 and MCF-10A cells. Further investigation into LP-scFv's mechanism revealed that the induced leader peptide does not alter the MAPK-ERK1/2 and PI3K/AKT pathways of single-chain antibodies. An enhanced antitumor activity was also confirmed in an NCI-N87 tumor xenograft model in mice with a reduction of 45.2% in tumor growth inhibition (vs. 23.1% for scFv) with a 50 mg/kg dose after orthotopic injection administration, which was equivalent to that of trastuzumab (vs. 55.7% for trastuzumab). Overall, these results indicate that LP-scFv exhibits significant permeation activity in HER2-positive cells to enhance the intracellular dose effect on antitumor activity in vitro and in vivo. This research lays the foundation for designing novel antibody-based therapies for cancer. [ABSTRACT FROM AUTHOR]

HER2-positive breast cancer is associated with aggressive behavior and reduced survival rates. Calcitriol restores the antiproliferative activity of antiestrogens in estrogen receptor (ER)-negative breast cancer cells by re-expressing ERα. Furthermore, calcitriol and its analog, EB1089, enhance responses to standard anti-cancer drugs. Therefore, we aimed to investigate EB1089 effects when added to the combined treatment of lapatinib and antiestrogens on the proliferation of HER2-positive breast cancer cells. BT-474 (ER-positive/HER2-positive) and SK-BR-3 (ER-negative/HER2-positive) cells were pre-treated with EB1089 to modulate ER expression. Then, cells were treated with EB1089 in the presence of lapatinib with or without the antiestrogens, and proliferation, phosphorylation array assays, and Western blot analysis were performed. The results showed that EB1089 restored the antiproliferative response to antiestrogens in SK-BR-3 cells and improved the inhibitory effects of the combination of lapatinib with antiestrogens in the two cell lines. Moreover, EB1089, alone or combined, modulated ERα protein expression and reduced Akt phosphorylation in HER2-positive cells. EB1089 significantly enhanced the cell growth inhibitory effect of lapatinib combined with antiestrogens in HER2-positive breast cancer cells by modulating ERα expression and Akt phosphorylation suppression. These results highlight the potential of this therapeutic approach as a promising strategy for managing HER2-positive breast cancer. [ABSTRACT FROM AUTHOR]

Background: Recent investigations have reported the benefits of using a tyrosine kinase inhibitor, dasatinib (DA), as well as programmed death-ligand 1 (PD-L1) inhibitors in the management of several solid tumors, including breast cancer. Nevertheless, the outcome of the combination of these inhibitors on HER2-positive breast cancer is not explored yet. Methods: Herein, we investigated the impact of DA and PD-L1 inhibitor (BMS-202) combination on HER2-positive breast cancer cell lines, SKBR3 and ZR75. Results: Our data reveal that the combination significantly inhibits cell viability of both cancer cell lines as compared to monotreatment. Moreover, the combination inhibits epithelial-mesenchymal transition (EMT) progression and reduces cancer cell invasion by restoring E-cadherin and β-catenin expressions and loss of vimentin, major biomarkers of EMT. Additionally, the combination reduces the colony formation of both cell lines in comparison with their matched control. Also, the combination considerably inhibits the angiogenesis of the chorioallantoic membrane model compared with monotreatment. Molecular pathway analysis of treated cells shows that this combination blocks HER2, AKT, β-catenin, and JNK1/2/3 activities. Conclusion: Our findings implicate that a combination of DA and BMS-202 could have a significant impact on the management of HER2-positive breast cancer. [ABSTRACT FROM AUTHOR]

Background: HER2-positive molecular breast cancer subtypes are characterized by high aggressiveness and malignancy, and their metastasis and mortality rates are among the highest of all types of breast cancer. The use of anti-HER2-targeted agents in neoadjuvant therapy has significantly improved the prognosis of patients with HER2-positive breast cancer. In this study, we investigated the efficacy and safety of a neoadjuvant Chinese THP regimen (docetaxel, trastuzumab biosimilar TQB211 plus the pertuzumab biosimilar TQB2440 or pertuzumab) for ER/PR-negative and HER2-positive breast cancer in China. Method: All enrolled patients received the THP regimen (T: docetaxel 75 mg/m2 per cycle; H: trastuzumab biosimilar TQB211 8 mg/kg in the first cycle and 6 mg/kg maintenance dose in cycles 2 to 4; P: pertuzumab biosimilar TQB2440 or pertuzumab 840 mg in the first cycle, maintenance dose 420 mg in cycles 2 to 4) every 3 weeks for 4 cycles. The biosimilar TQB2440 pertuzumab and pertuzumab were randomly assigned to patients. Docetaxel, TQB211, and TQB2440 were all developed by Chiatai Tianqing. The primary endpoint was the complete pathological response (pCR) in the breast, and the secondary endpoint was cardiac safety. Results: Of the 28 eligible patients, 19 (67.9%) achieved tpCR. The tpCR rate was higher than in the NeoSphere trial (pCR63.2%) and the PEONY study (tpCR52.5%). The adverse events that occurred most frequently were leukopenia and neutropenia, with incidence rates of 82.1% and 75.0%, respectively. Of these, grade 3 leukopenia and neutropenia occupied 46.4% and 35.7%. Other grade 3 or higher adverse events were bone marrow suppression (7.1%), lymphopenia (3.6%), and anemia (3.6%). There were no events of heart failure in patients and no patient died during the neoadjuvant phase. Conclusion: Domestic dual-target HP has a more satisfactory efficacy and safety in the neoadjuvant phase of treatment. Clinical trial registration: https://clinicaltrials.gov/study/ NCT05985187, NCT05985187. [ABSTRACT FROM AUTHOR]

Aim. To assess the incidence and timing of subclinical cardiac dysfunction associated with therapy for HER2-positive locally advanced or metastatic breast cancer, and to analyze the difference in time from significant reduction in left ventricular (LV) global longitudinal strain (GLS) to significant reduction in LV ejection fraction (LVEF) (cardiotoxicity "echo-loop").Material and methods. A total of 187 women 58±11 years without baseline cardiac dysfunction with verified HER2-positive locally advanced or metastatic breast cancer who received sequential adjuvant therapy with doxorubicin+cyclophosphamide, docetaxel+trastuzumab and trastuzumab monotherapy were followed up in 4 centers in four countries within 12 months with regular (every 3 weeks) speckle-tracking echocardiographic monitoring.Results. Subclinical cardiac dysfunction associated with breast cancer therapy (CTRCD) appears in each block of therapy after the first course. Its frequency increases significantly after each subsequent course compared to the previous one. By the end of the 4th course in each block of therapy, subclinical CTRCD is noted from 24,6% (almost every 4th patient in the chemotherapy block) to 32,6-33,7% (almost every 3rd patient in the chemotherapy and targeted therapy blocks). In 24 out of 25 cases of severe subclinical CTRCD (96%) with a fall in LVEF 15% was preceded. The time difference from a decrease in LV GLS to a decrease in LVEF

Abstract 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.

Neoadjuvant therapy is a preoperative systemic treatment for patients with breast cancer. This therapy has greatly improved the clinical outcomes of human epidermal growth factor receptor 2 (HER2)-positive breast cancer, which is associated with poor prognosis. Currently, dual anti-HER2 antibodies, including trastuzumab and pertuzumab, combined with non-anthracycline chemotherapy is one of the standard regimens to achieve high pathologic complete response rate and satisfactory efficacy. The combination of trastuzumab with tyrosine kinase inhibitors, antibody-drug conjugate drugs, or immunotherapy combined with target therapy, under the indications of reasonable biomarkers, is effective for HER2-positive breast cancer. In this article, we briefly reviewed neoadjuvant therapy in the dual-targeting therapy era and discussed its future perspectives.

In Mexico, breast cancer (BC) is the principal cause of death in women over 30 years old, with an annual mortality rate of 14.61 deaths per a 100,000 population. Chemotherapy, in combination with trastuzumab (TTZ), improves the survival of cancer patients; however, cardiotoxicity (CT) is the principal consequence. CT prevalence occurs between 10% and 30% of patients; however, there are no data about the prevalence of CT in the Mexican population. This study aims to establish the prevalence of CT in patients treated with anti-HER-2 therapy among BC women in southeast Mexico. A retrospective cross-sectional study was carried out from January 2015 to July 2019. The records of 46 patients diagnosed with HER-2-positive BC who attended the Mexican Social Security Institute in the Ambulatory Care Medicine Unit were analyzed. The diagnostic criterion for CT was a decrease in LVEF > 10% from baseline or a final LVEF < 53%. CT prevalence was observed in 19 (41.3%) of women with cancer, with an average decrease in LVEF of 13%. In the population, we found an association between weight, surface area, and the loading dose of TTZ with CT. Nutritional follow-up and the administration of cardioprotective drugs are necessary to recover LVEF and avoid cardiovascular failure in women with BC and survivors.