Clinical Outcomes in Patients with Early Stage Node-Negative HER2-Positive Breast Cancer Receiving Upfront Surgery or Neoadjuvant Systemic Therapy.

BACKGROUND: HER2-positive breast cancer is traditionally treated with neoadjuvant systemic therapy (NST), but optimal treatment sequencing is less clear in patients with small tumors. We investigated clinicopathologic and oncologic outcomes in early stage HER2-positive breast cancer. PATIENTS AND METHODS: An institutional database was queried to identify patients with cT1-2 (≤ 3 cm) N0M0, HER2-positive breast cancer treated from 2015 to 2020 and compared upfront surgery and NST cohorts. Logistic regression was performed to identify factors predicting upstaging. Survival outcomes by group were compared using log-rank tests. RESULTS: Of 256 patients identified, 170 (66.4%) received upfront surgery and 86 (33.6%) NST. The NST cohort was younger and had more cT2 and grade 3 tumors and negative sentinel nodes. There was no significant difference in type of breast surgery or receipt of axillary lymphadenectomy. After upfront surgery, 4 (2.4%) patients had upstaging to pT > 3 cm and 18 (10.6%) to pN1-3. No factors predicted upstaging. After NST, 47 (54.7%) achieved pathologic complete response and 3 (3.5%) had upstaging to ypN1-3 with older age (OR 1.08, p = 0.004) and hormone receptor-positive status (OR 7.07, p = 0.002) identified as predictors. At median follow-up of 3.55 years, 10 (3.9%) patients had recurrence and 5 (2.0%) patients died. There were no significant differences in oncologic outcomes between groups. CONCLUSIONS: Patients with cT1-2 (≤ 3 cm)N0 HER2-positive breast cancer selected for NST have higher-risk disease. Low rates of pathologic upstaging were observed with no difference in surgical treatments and overall excellent oncologic outcomes in both groups. These findings may guide decision-making regarding treatment sequencing for patients with early stage HER2-positive disease.

Characteristics of sphingomyelin metabolism in the MCF7 and BT474 radiotherapy­resistant HER2­positive breast cancer cell lines.

Breast cancer is the most common cancer globally in terms of incidence. This cancer is classified into subtypes based on histological or immunological characteristics. HER2-positive cases account for 15-25% of breast cancer cases, and one of the first events in breast carcinogenesis is HER2 upregulation. Furthermore, HER2 expression increases the detection rate of metastatic or recurrent breast cancers by 50-80%. The epidermal growth factor receptor family includes HER2, which is a transmembrane receptor protein. In our previous case report, patients who were resistant to anti-HER2 monoclonal antibody therapy, chemotherapy and radiotherapy had higher concentrations of phospholipid metabolites such as phosphatidylcholine and sphingomyelin (SM), which was associated with cancer recurrence progression. To better understand the relationship between radiotherapy resistance and SM expression, breast cancer cell lines with and without HER2 expression (MCF7 and BT474) after exposure to ionizing radiation (IR) were examined. In the cell culture supernatant, similar levels of SM in MCF7 cells were identified after 1-4 Gy exposure. However, SM levels in BT474 cells were upregulated compared with those of in the control group. Intracellular SM levels were upregulated in BT474 cells exposed to 1 and 4 Gy compared with the non-irradiated control group. Furthermore, significantly increased mRNA expression levels of sphingomyelin synthase 2 (SGMS2) in BT474 cells exposed to IR were observed compared with those in nonirradiated cells; however, the SGMS2 levels in MCF7 cells did not differ significantly among the 0, 2 and 4 Gy groups. These findings suggested that a higher dose of IR induced the secretion of SM and its associated gene expression in HER2-positive breast cancer cells.

The longitudinal changes in multiparametric MRI during neoadjuvant chemotherapy can predict treatment response early in patients with HER2-positive breast cancer.

PURPOSE: To investigate whether longitudinal changes in multiparametric MRI can predict early response to neoadjuvant chemotherapy (NAC) for HER2-positive breast cancer (BC) and to further establish quantitative models based on these features. METHODS: A total of 164 HER2-positive BC patients from three centers were included. MRI was performed at baseline and after two cycles of NAC (early post-NAC). Clinicopathological characteristics were enrolled. MRI features were evaluated at baseline and early post-NAC, as well as longitudinal changes in multiparametric MRI, including changes in the largest diameter (LD) of the tumor (ΔLD), apparent diffusion coefficient (ADC) values (ΔADC), and time-signal intensity curve (TIC) (ΔTIC). The patients were divided into a training set (n = 95), an internal validation set (n = 31), and an independent external validation set (n = 38). Univariate and multivariate logistic regression analyses were used to identify the independent indicators of pCR, which were then used to establish the clinicopathologic model and combined model. The AUC was used to evaluate the predictive power of the different models and calibration curves were used to evaluate the consistency of the prediction of pCR in different models. Additionally, decision curve analysis (DCA) was employed to determine the clinical usefulness of the different models. RESULTS: Two models were enrolled in this study, including the clinicopathologic model and the combined model. The LD at early post-NAC (OR=0.913, 95 % CI=0.953-0.994 p = 0.026), ΔADC (OR=1.005, 95 % CI=1.005-1.008, p = 0.007), and ΔTIC (OR=3.974, 95 % CI=1.276-12.358, p = 0.017) were identified as the best predictors of NAC response. The combined model constructed by the combination of LD at early post-NAC, ΔADC, and ΔTIC showed good predictive performance in the training set (AUC=0.87), internal validation set (AUC=0.78), and external validation set (AUC=0.79), which performed better than the clinicopathologic model in all sets. CONCLUSIONS: The changes in multiparametric MRI can predict early treatment response for HER2-positive BC and may be helpful for individualized treatment planning.

Prognostic factors of patients with human epidermal growth factor receptor 2-positive breast cancer following neoadjuvant therapy: Development and validation of a predictive nomogram.

OBJECTIVE: Human epidermal growth factor receptor 2 (HER2)-positive breast cancer exhibits an aggressive phenotype and poor prognosis. The application of neoadjuvant therapy (NAT) in patients with breast cancer can significantly reduce the risks of disease recurrence and improve survival. By integrating different clinicopathological factors, nomograms are valuable tools for prognosis prediction. This study aimed to assess the prognostic value of clinicopathological factors in patients with HER2-positive breast cancer and construct a nomogram for outcome prediction. METHODS: We retrospectively analyzed the clinicopathological data from 374 patients with breast cancer admitted to the Fourth Hospital of Hebei Medical University between January 2009 and December 2017, who were diagnosed with invasive breast cancer through preoperative core needle biopsy pathology, underwent surgical resection after NAT, and were HER2-positive. Patients were randomly divided into a training and validation set at a ratio of 7:3. Univariate and multivariate survival analyses were performed using Kaplan-Meier and Cox proportional hazards regression models. Results of the multivariate analysis were used to create nomograms predicting 3-, 5-, and 8-year overall survival (OS) rates. Calibration curves were plotted to test concordance between the predicted and actual risks. Harrell C-index and time-dependent receiver operating characteristic (ROC) curves were used to evaluate the discriminability of the nomogram prediction model. RESULTS: All included patients were women, with a mean age of 50 ± 10.4 years (range: 26-72 years). In the training set, both univariate and multivariate analyses identified residual cancer burden (RCB) class, tumor-infiltrating lymphocytes(TILs), and clinical stage as independent prognostic factors for OS, and these factors were combined to construct a nomogram. The calibration curves demonstrated good concordance between the predicted and actual risks, and the C-index of the nomogram was 0.882 (95 % CI 0.863-0.901). The 3-, 5-, and 8-year areas under the ROC curve (AUCs) were 0.909, 0.893, and 0.918, respectively, indicating good accuracy of the nomogram. The calibration curves also demonstrated good concordance in the validation set, with a C-index of 0.850 (95 % CI 0.804-0.896) and 3-, 5-, and 8-year AUCs of 0.909, 0.815, and 0.834, respectively, which also indicated good accuracy. CONCLUSION: The nomogram prediction model accurately predicted the prognostic status of post-NAT patients with breast cancer and was more accurate than clinical stage and RCB class. Therefore, it can serve as a reliable guide for selecting clinical treatment measures for breast cancer.

tRF-27 competitively Binds to G3BPs and Activates MTORC1 to Enhance HER2 Positive Breast Cancer Trastuzumab Tolerance.

About 20% of breast cancer patients are positive for HER2. The efficacy of current treatments is limited by primary and secondary resistance to trastuzumab. tRNA-derived fragments (tRFs) have shown crucial regulatory roles in various cancers. This study aimed to evaluate the role of tRF-27 in regulating the resistance of HER2-positive breast cancer against trastuzumab. tRF-27 was highly expressed in trastuzumab-resistant cells, and its expression level could predict the resistance to trastuzumab. High expression of tRF-27 promoted the growth and proliferation of trastuzumab-exposed cells. RNA-pulldown assay and mass spectrometry were performed to identify Ras GTPase-activating protein-binding proteins 1 and 2 (G3BPs) (two proteins targeted by tRF-27); RNA-immunoprecipitation (RIP) to confirm their bindings; co-immunoprecipitation (co-IP) and RNA-pulldown assay to determine the binding domains between G3BPs and tRF-27.tRF-27 bound to the nuclear transport factor 2 like domain(NTF2 domain) of G3BPs through a specific sequence. tRF-27 relied on G3BPs and NTF2 domain to increase trastuzumab tolerance. tRF-27 competed with lysosomal associated membrane protein 1(LAMP1) for NTF2 domain, thereby inhibiting lysosomal localization of G3BPs and tuberous sclerosis complex (TSC). Overexpression of tRF-27 inhibited phosphorylation of TSCs and promoted the activation of mechanistic target of rapamycin complex 1(MTORC1) to enhance cell proliferation and entice the resistance of HER2-positive breast cancer against trastuzumab.

Preclinical and clinical evaluation through serial colonoscopic evaluation of neratinib-induced diarrhea in HER2-positive breast cancer-A pilot study.

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.

Clinical Treatment Score Post-5 Years (CTS5) and Late Recurrence Risk in Hormone Receptor-Positive, HER2-Positive Breast Cancer.

BACKGROUND: The Clinical Treatment Score post-5 years (CTS5) is a risk stratification tool used to determine the risk of late recurrence in hormone receptor-positive (HR+), HER2-negative breast cancer (BC). Limited data exist on its use in HR+, HER2-positive (HER2+) BC. PATIENTS AND METHODS: CTS5 was evaluated in HR+, HER2+ BC in the North Central Cancer Treatment Group (NCCTG) N9831 (Alliance) and NSABP B-31 (NRG) trials. RESULTS: A total of 1,862 patients with HR+, HER2+ BC without recurrence 5 years after enrollment were included. Overall, the CTS5 score was significantly associated with recurrence-free survival (RFS), with a hazard ratio (HR) of 1.35 (95% CI, 1.12-1.63; P=.002), but did not reach statistical significance in patients who received trastuzumab (n=829; HR, 1.29; 95% CI, 0.98-1.71; P=.07). CTS5 risk category was not significantly associated with RFS. In patients who received trastuzumab, other variables used in CTS5, including patient age and tumor size, were not significantly associated with RFS. N3 was significantly associated with worse outcomes (HR, 1.86; 95% CI, 1.09-3.17; P=.02) compared with N0-N1. Paradoxically, higher tumor grade was associated with better outcomes after 5 years in the multivariate analysis (HR, 0.71; 95% CI, 0.50-1.00; P=.05). The incidence of recurrences or deaths between years 5 to 10 was 10.6% in the CTS5 low-risk category, 5.6% in the intermediate-risk category, and 9.8% in the high-risk category. CONCLUSIONS: The CTS5 model does not accurately predict the risk of late recurrence in HR+, HER2+ BC treated with adjuvant trastuzumab in the N9831 and B-31 trials. This study underlines the need to develop a new prognostic model to better delineate the risk of late recurrence in patients with HR+, HER2+ BC receiving adjuvant trastuzumab. CLINICALTRIALS: gov identifiers: NCT00005970 (NCCTG N9831) and NCT00004067 (NRG/NSABP B-31).

Additional statin treatment enhances the efficacy of HER2 blockade and improves prognosis in Rac1-high/HER2-positive breast cancer.

The prognosis of HER2-positive breast cancer (BC) has improved with the development of anti-HER2 therapies; however, the problem remains that there are still cases where anti-HER2 therapies do not respond well. We found that the expression of SREBF2, a master transcriptional factor in the mevalonate pathway, was correlated with ERBB2 (HER2) expression and a poor prognosis in HER2-positive BC. The target gene expressions of SREBF2 were associated with higher expression of ERBB2 in HER2-positive BC cells. Statins, anti-hypercholesterolemia drugs that inhibit the mevalonate pathway, enhanced the efficacy of HER2-targeting agents with inducing apoptosis in a geranylgeranylation-dependent manner. Mechanistically, statins specifically inhibited membrane localization of Rac1, a target protein of geranylgeranylation, and suppressed the activation of HER2 downstreams AKT and ERK pathways. Consistently, retrospective analysis showed a longer recurrence-free survival in Rac1-high/HER2-positive BC patients treated with HER2-targeting agents with statins than without statins. Our findings thus suggest that Rac1 expression could be used as a biomarker to stratify HER2-positive BC patients that could benefit from dual blockade, i.e., targeting HER2 with inhibition of geranylgeranylation of Rac1 using statins, thereby opening avenues for precision medicine in a new subset of Rac1-high/HER2-positive BC.

LncRNA ZNF649-AS1 promotes trastuzumab resistance and TAM-dependent PD-L1 expression in breast cancer by regulating EXOC7 alternative splicing.

BACKGROUND: Trastuzumab resistance is a serious clinical problem in the treatment of HER2-positive breast cancer (BC). The lncRNA ZNF649-AS1 was previously found to promote HER2-positive BC trastuzumab resistance. The study aims to explore the molecular mechanism of ZNF649-AS1 in HER2-positive BC trastuzumab resistance. METHODS: Tumor tissue and peripheral blood samples were collected from 20 HER2-positive BC patients with trastuzumab-resistant and non-resistant, respectively. Trastuzumab-resistant BC cell lines SKBR-3-TR and BT474-TR were established. RIP was employed to confirm the binding of ZNF649-AS1, PRPF8 and exocyst complex component 7 (EXOC7). RNA expression of EXOC7-L (Full length of EXOC7) and EXOC7-S (Spliceosome of EXOC7) were detected using agarose gel electrophoresis. Expressions of macrophage markers CD68+ CD206+ were measured by flow cytometry. RESULTS: ZNF649-AS1 expression was upregulated in HER2-positive BC trastuzumab resistance. ZNF649-AS1 downregulation inhibited trastuzumab resistance in HER2-positive BC. ZNF649-AS1 regulated EXOC7 alternative splicing by binding with PRPF8. EXOC7-S knockdown suppressed trastuzumab resistance and TAM-dependent PD-L1 expression in HER2-positive BC. EXOC7-S overexpression abolished the effects of ZNF649-AS1 knockdown on trastuzumab resistance and TAM-dependent PD-L1 expression in HER2-positive BC. CONCLUSION: ZNF649-AS1 promoted trastuzumab resistance and TAM-dependent PD-L1 expression in HER2-positive BC via promoting alternative splicing of EXOC7 by PRPF8.

A Novel Signature Based on Angiogenesis-Related Genes Predicts the Prognosis and Immunotherapy Response in HER2-Positive Breast Cancer.

Background: HER2-positive breast cancer is one of the most prevalent subtypes of breast cancer and represents a significant health concern for women worldwide due to its high morbidity and mortality rates. Recent studies have consistently underscored the pivotal role of angiogenesis in the development and progression of HER2-positive breast cancer. Here, we developed a prognostic signature based on angiogenesis-related genes (ARGs) to categorize HER2-positive breast cancer patients and provide insights into their survival outcomes. Methods: Kaplan-Meier survival curve, time-dependent receiver operating characteristic (ROC) and nomogram were performed to investigate the prognostic performance of the signature. In addition, we comprehensively analyzed the correlation of the prognostic signature with immune cell infiltration, immune checkpoint inhibitors (ICIs) therapy. Finally, Immunohistochemistry (IHC) and immunoblotting were used to investigate XBP1 expression in HER2-positive breast cancer tissues. Colony formation assay was performed to examine cell proliferation of HER2-positive breast cancer cells. Results: The Kaplan-Meier curves and the ROC curves demonstrated that the ARGs had good performance in predicting the prognosis of HER2-positive breast cancer patients. In addition, we observed that the low-risk group was remarkably associated with immune infiltration and better response to ICIs. Further experimental results show that XBP1 is upregulated in human HER2-positive breast cancer, and its knockdown significantly inhibited cell proliferation. Conclusions: Our study demonstrated that the ARGs could serve as a novel biomarker for predicting the prognosis of patients with HER2-positive breast cancer and providing new insights into immunotherapy strategies for these patients.

Tailoring neo/adjuvant systemic therapy in breast cancer: "The advent of a personalized approach"-The Breast-Gynecological and Immuno-Oncology International Cancer Conference (BGICC) consensus and recommendations.

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.

Discovery of indazole inhibitors for heat shock protein 90 as anti-cancer agents.

A series of indazole analogs, derived from the B,C-ring-truncated scaffold of deguelin, were designed to function as C-terminal inhibitors of heat shock protein 90 (HSP90) and investigated as novel antitumor agents against HER2-positive breast cancer. Among the synthesized compounds, compound 12d exhibited substantial inhibitory effects in trastuzumab-sensitive (BT474) and trastuzumab-resistant (JIMT-1) breast cancer cells, with IC50 values of 6.86 and 4.42 µM, respectively. Notably, compound 12d exhibited no cytotoxicity in normal cells. Compound 12d markedly downregulated the expression of the major HSP90 client proteins in both cell types, attributing its cytotoxicity to the destabilization and inactivation of HSP90 client proteins. Molecular docking studies using the homology model of an HSP90 homodimer demonstrated that inhibitor 12d fit nicely into the C-terminal domain, boasting a higher electrostatic complementary score than ATP. In vivo pharmacokinetic study indicated the high oral bioavailability of compound 12 d at F = 66.9 %, while toxicological studies indicated its negligible impact on hERG channels and CYP isozymes. Genotoxicity tests further confirmed its safety profile. The findings collectively position compound 12d as a promising candidate for further development as an antitumor agent against HER2-positive breast cancer.

Cost-utility and budget impact analysis of neoadjuvant dual HER2 targeted therapy for HER2-positive breast cancer in Sri Lanka.

This study aimed to assess the cost-utility and budget impact of dual to single HER2 targeted neoadjuvant therapy for HER2-positive breast cancer in Sri Lanka. A five-health state Markov model with lifetime horizon was used to assess the cost-utility of neoadjuvant trastuzumab (T) plus pertuzumab (P) or lapatinib (L) compared to single therapy of T with chemotherapy (C), in public healthcare system and societal perspectives. Input parameters were estimated using local data, network meta-analysis, published reports and literature. Costs were adjusted to year 2021 (1USD = LKR194.78). Five-year budget impact for public healthcare system was assessed. Incremental cost-effectiveness ratios in societal perspective for neoadjuvantLTC plus adjuvantT (strategy 3), neoadjuvantPTC plus adjuvantT (strategy 2), neoadjuvantLTC plus adjuvantLT (strategy 5), and neoadjuvantPTC plus adjuvantPT (strategy 4) compared to neoadjuvantTC plus adjuvantT (strategy 1) were USD2716, USD5600, USD6878, and USD12127 per QALY gained, respectively. One GDP per-capita (USD3815) was considered as the cost-effectiveness threshold for the analysis. Even though only the ICER for strategy 3 was cost-effective, uncertainty of efficacy parameter was revealed. For strategy 2 neoadjuvant PTC plus adjuvant T, a 25% reduction of neoadjuvant regimen cost was required to be cost effective for use in early HER2 positive breast cancer.

Diffusion-weighted imaging in addition to contrast-enhanced MRI in identifying complete response in HER2-positive breast cancer.

OBJECTIVES: The aim of this study is to investigate the added value of diffusion-weighted imaging (DWI) to dynamic-contrast enhanced (DCE)-MRI to identify a pathological complete response (pCR) in patients with HER2-positive breast cancer and radiological complete response (rCR). MATERIALS AND METHODS: This is a single-center observational study of 102 patients with stage I-III HER2-positive breast cancer and real-world documented rCR on DCE-MRI. Patients were treated between 2015 and 2019. Both 1.5 T/3.0 T single-shot diffusion-weighted echo-planar sequence were used. Post neoadjuvant systemic treatment (NST) diffusion-weighted images were reviewed by two readers for visual evaluation and ADCmean. Discordant cases were resolved in a consensus meeting. pCR of the breast (ypT0/is) was used to calculate the negative predictive value (NPV). Breast pCR-percentages were tested with Fisher's exact test. ADCmean and ∆ADCmean(%) for patients with and without pCR were compared using a Mann-Whitney U-test. RESULTS: The NPV for DWI added to DCE is 86% compared to 87% for DCE alone in hormone receptor (HR)-/HER2-positive and 67% compared to 64% in HR-positive/HER2-positive breast cancer. Twenty-seven of 39 non-rCR DWI cases were false positives. In HR-positive/HER2-positive breast cancer the NPV for DCE MRI differs between MRI field strength (1.5 T: 50% vs. 3 T: 81% [p = 0.02]). ADCmean at baseline, post-NST, and ∆ADCmean were similar between patients with and without pCR. CONCLUSION: DWI has no clinically relevant effect on the NPV of DCE alone to identify a pCR in early HER2-positive breast cancer. The added value of DWI in HR-positive/HER2-positive breast cancer should be further investigated taken MRI field strength into account. CLINICAL RELEVANCE STATEMENT: The residual signal on DWI after neoadjuvant systemic therapy in cases with early HER2-positive breast cancer and no residual pathologic enhancement on DCE-MRI breast should not (yet) be considered in assessing a complete radiologic response. KEY POINTS: Radiologic complete response is associated with a pathologic complete response (pCR) in HER2+ breast cancer but further improvement is warranted. No relevant increase in negative predictive value was observed when DWI was added to DCE. Residual signal on DW-images without pathologic enhancement on DCE-MRI, does not indicate a lower chance of pCR.

Exploring the feasibility and implications of cranioencephalic computed tomography in HER2-positive breast cancer: A pilot study.

Background: Breast cancer has several subtypes, including HER2-positive breast cancer, which is characterized by overexpression of human epidermal growth factor receptor 2 (HER2), aggressiveness, poor prognosis, and high risk of recurrence and metastasis. Brain metastases are a common complication of HER2-positive breast cancer, but brain imaging is not included in the initial staging of this disease. This prospective pilot study aimed to evaluate the usefulness of brain computed tomography (CT) in the initial staging of HER2-positive breast cancer. Patients and methods: Fifty-eight patients were enrolled and demographic, clinical, and breast cancer-specific data were collected after the informed consent and ethical approval were obtained. Results: A descriptive analysis was performed. The median age of the patients was 55 years, and the majority had good performance status. Brain CT scans were performed at diagnosis, and no brain metastases were detected in early-stage patients. However, brain CT identified brain metastases in one advanced-stage patient with clinical suspicion. Conclusions: This study suggests that brain CT may have limited utility in the initial staging of early HER2-positive breast cancer, while it could be a valuable tool in advanced cases. Further research is needed, including a higher number of patients to identify those with high risk, which may benefit from brain imaging.

Efficacy and safety of first-line regimens for advanced HER2-positive breast cancer: A Bayesian network meta-analysis.

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.

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

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

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

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

Neoadjuvant inetetamab and pertuzumab with taxanes and carboplatin (TCbIP) In locally advanced HER2-positive breast cancer: a prospective cohort study with propensity-matched analysis.

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).