Outcomes following stereotactic radiosurgery or whole brain radiation therapy by molecular subtype of metastatic breast cancer

BackgroundThis study quantified clinical outcomes by molecular subtype of metastatic breast cancer (BC) following whole brain radiation therapy (WBRT) or stereotactic radiosurgery (SRS). Doing so is important for patient counseling and to assess the potential benefit of combining targeted therapy and brain radiotherapy for certain molecular subtypes in ongoing trials.Materials and methodsThe National Cancer Database was queried for BC (invasive ductal carcinoma) cases receiving brain radiotherapy (divided into WBRT and SRS ). Statistics included multivariable logistic regression to determine factors associated with SRS delivery, Kaplan-Meier analysis to evaluate overall survival (OS), and Cox proportional hazards modeling.ResultsOf 1,112 patients, 186 (16.7%) received SRS and 926 (83.3%) underwent WBRT. Altogether, 410 (36.9%), 195 (17.5%), 162 (14.6%), and 345 (31.0%) were ER+/HER2−, ER+/HER2+, ER−/HER2+, and ER−/HER2−, respectively. In the respective molecular subtypes, the proportion of subjects who underwent SRS was 13.4%, 19.4%, 24.1%, and 15.7%. Respective OS for WBRT patients were 12.9, 22.8, 10.6, and 5.8 months; corresponding figures for the SRS cohort were 28.3, 40.7, 15.0, and 12.9 months (p < 0.05 for both). When comparing OS between treatment different histologic subtypes, patients with ER−/HER2+ and ER−/HER2− disease had worse OS than patients with ER+/HER2− disease, for both patients treated with SRS and for patients treated with WBRT.ConclusionsMolecular subtype may be a useful prognostic marker to quantify survival following SRS/WBRT for metastatic BC. Patients with HER 2-enriched and triple-negative disease had the poorest survival following brain irradiation, lending credence to ongoing studies testing the addition of targeted therapies for these subtypes.     

The Promher Study: An Observational Italian Study on Adjuvant Therapy for HER2-Positive,pT1a-b pN0 Breast Cancer

BackgroundThe management of pT1a-b pN0 HER2-positive breast cancer is controversial and no data about the efficacy of trastuzumab in this setting are available from randomized clinical trials. The aims of this retrospective study were to assess how patients are managed in clinical practice in Italy, which clinical or biological characteristics influenced the choice of adjuvant systemic therapy and the outcome of patients.MethodsData of consecutive patients who underwent surgery from January 2007 to December 2012 for HER2-positive, pT1a-b pN0 M0 breast cancer were retrospectively collected from 28 Italian centres. Analysis of contingency tables and multivariate generalized logit models were used to investigate the association between the baseline clinical and biological features and the treatment strategy adopted.ResultsAmong 303 enrolled patients, 204 received adjuvant systemic therapy with trastuzumab, 65 adjuvant systemic therapy without trastuzumab and 34 did not receive adjuvant systemic therapy. At the multivariate analysis age, tumor size, proliferation index and hormone receptor status were significantly associated with the treatment choice. Five-year disease-free survival (DFS) probability was 95%, 94.3% and 69.6% for patients treated with adjuvant systemic therapy and trastuzumab, with adjuvant systemic therapy without trastuzumab and for patients who did not receive adjuvant systemic therapy, respectively (p<0.001).ConclusionsThe majority of patients (66%) with pT1a-b pN0 HER2-positive breast cancer enrolled in this retrospective study received adjuvant systemic therapy with trastuzumab, whereas only 11% patients did not receive any adjuvant systemic therapy. The choice of treatment type seems to be mainly influenced by tumor size, proliferation index, hormone receptor status and age. The 5-year DFS probability was significantly higher for patients receiving adjuvant systemic therapy with trastuzumab compared with patients not receiving adjuvant systemic therapy or receiving adjuvant systemic therapy without trastuzumab.     

Efficacy and Safety of HER2-Targeted Agents for Breast Cancer with HER2-Overexpression: A Network Meta-Analysis

BackgroundClinical trials of human epidermal growth factor receptor 2 (HER2)-targeted agents added to standard treatment have been efficacious for HER2-positive (HER2+) advanced breast cancer. To our knowledge, no meta-analysis has evaluated HER2-targeted therapy including trastuzumab emtansine (T-DM1) and pertuzumab for HER2-positive breast caner and ranked the targeted treatments. We performed a network meta-analysis of both direct and indirect comparisons to evaluate the effect of adding HER2-targeted agents to standard treatment and examined side effects.MethodsWe performed a Bayesian-framework network meta-analysis of randomized controlled trials to compare 6 HER2-targeted treatment regimens and 1 naïve standard treatment (NST, without any-targeted drugs) in targeted treatment of HER2+ breast cancer in adults. These treatment regimens were T-DM1, LC (lapatinib), HC (trastuzumab), PEC (pertuzumab), LHC (lapatinib and trastuzumab), and PEHC (pertuzumab and trastuzumab). The main outcomes were overall survival and response rates. We also examined side effects of rash, LVEF (left ventricular ejection fraction), fatigue, and gastrointestinal disorders, and performed subgroup analysis for the different treatment regimens in metastatic or advanced breast cancer.ResultsWe identified 25 articles of 21 trials, with data for 11,276 participants. T-DM1 and PEHC were more efficient drug regimens with regard to overall survival as compared with LHC, LC, HC and PEC. The incidence of treatment-related rash occurs more frequently in the patients who received LC treatment regimen than PEHC and T-DM1 and HC. In subgroup analysis, T-DM1 was associated with increased overall survival as compared with LC and HC. PEHC was associated with increased overall response as compared with LC, HC, and NST.ConclusionsOverall, the regimen of T-DM1 as well as pertuzumab in combination with trastuzumab and docetaxel is efficacious with fewer side effects as compared with other regimens, especially for advanced HER2+ breast cancer.ImpactThis study suggests that both T-DM1 and PEHC therapy are potentially and equally useful treatments for HER2+ breast cancer.     

Efficacy and safety of trastuzumab with or without a tyrosine kinase inhibitor for HER2-positive breast cancer: A systematic review and meta-analysis

BackgroundThis study aimed to explore the efficacy and safety of trastuzumab plus tyrosine kinase inhibitors (TKIs) compared with those of trastuzumab monotherapy in patients with human epidermal growth factor receptor (HER2)-positive breast cancer.MethodsThe PubMed, Embase, Cochrane, and Web of Science databases were systematically searched for relevant articles from inception until September 2022. The primary outcomes were overall survival (OS) and progression-free survival (PFS). Subgroup analyses were performed based on disease status, TKI type, and hormone receptor status.ResultsSixteen studies were included in the current analysis. Trastuzumab plus TKI significantly improved OS and PFS compared to trastuzumab monotherapy. In the neoadjuvant setting, trastuzumab plus TKI significantly increased the pathologic complete response (pCR) rate compared to trastuzumab monotherapy. Moreover, a higher objective response rate (ORR) was observed with trastuzumab plus TKI. Patients who received the combination therapy had a higher incidence of discontinuation, all-grade diarrhea, and grade ≥ 3 diarrhea.ConclusionsTrastuzumab plus TKI was better than trastuzumab monotherapy for treating different stages of HER2-positive breast cancer. The safety of trastuzumab plus TKI anti-HER2 therapy was controllable. The different efficacies of TKIs combined with trastuzumab may be related to the mechanism of action of the different TKIs, needing further investigations.     

Adoptive transfer of autologous, HER2-specific, cytotoxic T lymphocytes for the treatment of HER2-overexpressing breast cancer

The human epidermal growth factor receptor 2 (HER2) has been targeted as a breast cancer-associated antigen by immunotherapeutical approaches based on HER2-directed monoclonal antibodies and cancer vaccines. We describe the adoptive transfer of autologous HER2-specific T-lymphocyte clones to a patient with metastatic HER2-overexpressing breast cancer. The HLA/multimer-based monitoring of the transferred T lymphocytes revealed that the T cells rapidly disappeared from the peripheral blood. The imaging studies indicated that the T cells accumulated in the bone marrow (BM) and migrated to the liver, but were unable to penetrate into the solid metastases. The disseminated tumor cells in the BM disappeared after the completion of adoptive T-cell therapy. This study suggests the therapeutic potential for HER2-specific T cells for eliminating disseminated HER2-positive tumor cells and proposes the combination of T cell-based therapies with strategies targeting the tumor stroma to improve T-cell infiltration into solid tumors.     

HER2-positive circulating tumor cells in breast cancer

Purpose

Circulating Tumor Cells (CTCs) detection and phenotyping are currently evaluated in Breast Cancer (BC). Tumor cell dissemination has been suggested to occur early in BC progression. To interrogate dissemination in BC, we studied CTCs and HER2 expression on CTCs across the spectrum of BC staging.

Methods

Spiking experiments with 6 BC cell lines were performed and blood samples from healthy women and women with BC were analyzed for HER2-positive CTCs using the CellSearch®.

Results

Based on BC cell lines experiments, HER2-positive CTCs were defined as CTCs with HER2 immunofluoresence intensity that was at least 2.5 times higher than the background. No HER2-positive CTC was detected in 42 women without BC (95% confidence interval (CI) 0–8.4%) whereas 4.1% (95%CI 1.4–11.4%) of 73 patients with ductal/lobular carcinoma in situ (DCIS/LCIS) had 1 HER2-positive CTC/22.5 mL, 7.9%, (95%CI 4.1–14.9%) of 101 women with non metastatic (M0) BC had ≥1 HER2-positive CTC/22.5 mL (median 1 cell, range 1–3 cells) and 35.9% (95%CI 22.7–51.9%) of 39 patients with metastatic BC had ≥1 HER2-positive CTC/7.5 mL (median 1.5 cells, range 1–42 cells). In CTC-positive women with DCIS/LCIS or M0 BC, HER2-positive CTCs were more commonly detected in HER2-positive (5 of 5 women) than HER2-negative BC (5 of 12 women) (p = 0.03).

Conclusion

HER2-positive CTCs were detected in DCIS/LCIS or M0 BC irrespective of the primary tumor HER2 status. Nevertheless, their presence was more common in women with HER2-positive disease. Monitoring of HER2 expression on CTCs might be useful in trials with anti-HER2 therapies.     

HER2 阳性乳腺癌转移患者最佳治疗方案的研究进展

针对人表皮生长因子受体HER2 的靶向制剂曲妥珠单抗,显著改善了HER2 阳性乳腺癌转移患者疾病的发展状况,提高了 患者的总体生存期（OS）,然而耐药现象时有发生。其它靶向制剂如帕妥珠单抗,酪氨酸激酶受体抑制剂拉帕替尼和ado-transtusumab emtansine等克服了其耐药性,为治疗提供了更多选择。这些HER2 靶向制剂单用或联用已显示出良好的临床功效,但最 佳治疗次序依然未知。随着新型靶向制剂的出现,最佳治疗方案的研究成为热点。本篇综述重点阐述了目前HER2 阳性乳腺癌转 移患者最佳治疗方案的研究进展,以及新型靶向制剂的现有状况。     

Lapatinib inhibits stem/progenitor proliferation in preclinical in vitro models of ductal carcinoma in situ (DCIS)

Breast-conserving surgery for ductal carcinoma in situ (DCIS) is often combined with irradiation, reducing recurrence rates to 20% within 10 years; however, there is no change in overall survival. Evidence in the invasive breast indicates that breast cancer stem cells (CSCs) are radiotherapy-resistant and are capable of re-initiating a tumor recurrence; hence, targeting CSCs in high risk DCIS patient may improve survival. HER2 is overexpressed in 20% of DCIS and is known to be highly active in breast CSCs; we therefore investigated the effect of Lapatinib on DCIS CSC activity using 2 in vitro culture systems. Two DCIS cell lines DCIS.com (HER2 normal) and SUM225 (HER2 overexpressed) as well as DCIS cells from patient samples (n = 18) were cultured as mammospheres to assess CSC activity and in differentiated 3D-matrigel culture to determine effects within the non-CSCs. Mammosphere formation was reduced regardless of HER2 status, although this was more marked within the HER2-positive samples. When grown as differentiated DCIS acini in 3D-matrigel culture, Lapatinib only reduced acini size in the HER2-positive samples via decreased proliferation. Further investigation revealed lapatinib did not reduce self-renewal activity in the CSC population, but their proliferation was decreased regardless of HER2 status. In conclusion we show Lapatinib can reduce DCIS CSC activity, suggesting that the use of Lapatinib in high-risk DCIS patients has the potential to reduce recurrence and the progression of DCIS to invasive disease.     

Human Epidermal Growth Factor Receptor 2 (HER2) Impedes MLK3 Kinase Activity to Support Breast Cancer Cell Survival

Human epidermal growth factor receptor 2 (HER2) is amplified in ∼15–20% of human breast cancer and is important for tumor etiology and therapeutic options of breast cancer. Up-regulation of HER2 oncogene initiates cascades of events cumulating to the stimulation of transforming PI3K/AKT signaling, which also plays a dominant role in supporting cell survival and efficacy of HER2-directed therapies. Although investigating the underlying mechanisms by which HER2 promotes cell survival, we noticed a profound reduction in the kinase activity of a pro-apoptotic mixed lineage kinase 3 (MLK3) in HER2-positive (HER2+) but not in HER2-negative (HER2−) breast cancer tissues, whereas both HER2+ and HER2− tumors expressed a comparable level of MLK3 protein. Furthermore, the kinase activity of MLK3 was inversely correlated with HER2+ tumor grades. Moreover, HER2-directed drugs such as trastuzumab and lapatinib as well as depletion of HER2 or HER3 stimulated MLK3 kinase activity in HER2+ breast cancer cell lines. In addition, the noted inhibitory effect of HER2 on MLK3 kinase activity was mediated via its phosphorylation on Ser⁶⁷⁴ by AKT and that pharmacological inhibitors of PI3K/AKT prevented trastuzumab- and lapatinib-induced stimulation of MLK3 activity. Consistent with the pro-apoptotic function of MLK3, stable knockdown of MLK3 in the HER2+ cell line blunted the pro-apoptotic effects of trastuzumab and lapatinib. These findings suggest that HER2 activation inhibits the pro-apoptotic function of MLK3, which plays a mechanistic role in mediating anti-tumor activities of HER2-directed therapies. In brief, MLK3 represents a newly recognized integral component of HER2 biology in HER2+ breast tumors.     

Efficacy of Lapatinib in Therapy-Resistant HER2-Positive Circulating Tumor Cells in Metastatic Breast Cancer

Background

To evaluate the efficacy of lapatinib, a dual EGFR and HER2 tyrosine kinase inhibitor, in therapy-resistant HER2-positive CTCs in metastatic breast cancer (MBC).

Patients and Methods

Patients with MBC and HER2-positive CTCs despite disease stabilization or response to prior therapy, received lapatinib 1500 mg daily in monthly cycles, till disease progression or CTC increase. CTC monitoring was performed by immunofluorescent microscopy using cytospins of peripheral blood mononuclear cells (PBMCs) double stained for HER2 or EGFR and cytokeratin.

Results

A total of 120 cycles were administered in 22 patients; median age was 62.5 years, 15 (68.2%) patients were post-menopausal and 20 (90.1%) had HER2-negative primary tumors. At the end of the second course, HER2-positive CTC counts decreased in 76.2% of patients; the median number of HER2-positive CTCs/patient also declined significantly (p = 0.013), however the decrease was significant only among patients presenting disease stabilization (p = 0.018) but not among those with disease progression during lapatinib treatment. No objective responses were observed. All CTC-positive patients harbored EGFR-positive CTCs on progression compared to 62.5% at baseline (p = 0.054). The ratio of EGFR-positive CTCs/total CTCs detected in all patients increased from 17.1% at baseline to 37.6% on progression, whereas the mean percentage of HER2-negative CTCs/patient increased from 2.4% to 30.6% (p = 0.03).

Conclusions

The above results indicate that lapatinib is effective in decreasing HER2-positive CTCs in patients with MBC irrespectively of the HER2 status of the primary tumor and imply the feasibility of monitoring the molecular changes on CTCs during treatment with targeted agents.

Trial Registration

Clinical trial.gov NCT00694252     

Switching addictions between HER2 and FGFR2 in HER2-positive breast tumor cells: FGFR2 as a potential target for salvage after lapatinib failure

Agents that target HER2 have improved the prognosis of patients with HER2-amplified breast cancers. However, patients who initially respond to such targeted therapy eventually develop resistance to the treatment. We have established a line of lapatinib-resistant breast cancer cells (UACC812/LR) by chronic exposure of HER2-amplified and lapatinib-sensitive UACC812 cells to the drug. The mechanism by which UACC812/LR acquired resistance to lapatinib was explored using comprehensive gene hybridization. The FGFR2 gene in UACC812/LR was highly amplified, accompanied by overexpression of FGFR2 and reduced expression of HER2, and a cell proliferation assay showed that the IC₅₀ of PD173074, a small-molecule inhibitor of FGFR tyrosine kinase, was 10,000 times lower in UACC812/LR than in the parent cells. PD173074 decreased the phosphorylation of FGFR2 and substantially induced apoptosis in UACC812/LR, but not in the parent cells. FGFR2 appeared to be a pivotal molecule for the survival of UACC812/LR as they became independent of the HER2 pathway, suggesting that a switch of addiction from the HER2 to the FGFR2 pathway enabled cancer cells to become resistant to HER2-targeted therapy. The present study is the first to implicate FGFR in the development of resistance to lapatinib in cancer, and suggests that FGFR-targeted therapy might become a promising salvage strategy after lapatinib failure in patients with HER2-positive breast cancer.     

Reverse-phase protein microarray highlights HER2 signaling activation in immunohistochemistry/FISH/HER2-negative breast cancers

Evaluation of: Wulfkuhle JD, Berg D, Wolff C et al. Molecular analysis of HER2 signaling in human breast cancer by functional protein pathway activation mapping. Clin. Cancer Res. 18(23), 6426–6435 (2012).

Exhaustive characterization and mapping of pivotal molecules and downstream effectors deregulated in breast cancer is of fundamental clinical value to define the most effective therapy. Wulfkuhle et al. applied reverse-phase protein microarray, a highly sensitive immunoassay able to perform quantitative and multiplexed analysis of total and/or modified cellular proteins, to assess protein levels and activation/phosphorylation status of the HER family (EGFR, HER2, HER3) and downstream signaling molecules in HER2⁺ and HER2^- breast cancers. The research was performed using laser capture microdissected tumor epithelial cells from frozen samples and formalin-fixed paraffin embedded specimens, which were also analyzed by immunohistochemistry (IHC) and FISH. This study identified a subgroup of IHC/FISH/HER2^- patients with HER2 activation/phosphorylation levels comparable with those obtained from IHC/FISH/HER2⁺ tumors. HER2 signaling activation was independent from total HER2 expression and involved HER3 and EGFR activation. These findings indicate that molecular characterization by reverse-phase protein microarray of HER2 and its partners/effectors in the signaling cascade enables the identification of a subgroup of IHC/FISH/HER2^- patients showing HER2 signaling activation. These patients, currently excluded from targeted therapy administration, could potentially benefit from this and it could improve prognosis and survival.     

Inhibitor of Apoptosis (IAP) survivin is indispensable for survival of HER2 gene-amplified breast cancer cells with primary resistance to HER1/2-targeted therapies

Primary resistance of HER2 gene-amplified breast carcinomas (BC) to HER-targeted therapies can be explained in terms of overactive HER2-independent downstream pro-survival pathways. We here confirm that constitutive overexpression of Inhibitor of Apoptosis (IAP) survivin is indispensable for survival of HER2-positive BC cells with intrinsic cross-resistance to multiple HER1/2 inhibitors. The IC₅₀ values for the HER1/2 Tyrosine Kinase Inhibitors (TKIs) gefitinib, erlotinib and lapatinib were up to 40-fold higher in trastuzumab-unresponsive JIMT-1 cells than in trastuzumab-naïve SKBR3 cells. ELISA-based and immunoblotting assays demonstrated that trastuzumab-refractory JIMT-1 cells constitutively expressed ∼4 times more survivin protein than trastuzumab-responsive SKBR3 cells. In response to trastuzumab, JIMT-1 cells accumulated ∼10 times more survivin than SKBR3 cells. HER1/2 TKIs failed to down-regulate survivin expression in JIMT-1 cells whereas equimolar doses of HER1/HER2 TKIs drastically depleted survivin protein in SKBR3 cells. ELISA-based detection of histone-associated DNA fragments confirmed that trastuzumab-refractory JIMT-1 cells were intrinsically protected against the apoptotic effects of HER1/2 TKIs. Of note, when we knocked-down survivin expression using siRNA and then added trastuzumab, cell proliferation and colony formation were completely suppressed in JIMT-1 cells. Our current findings may be extremely helpful to design successful combinatorial strategies aimed to circumvent the occurrence of de novo resistance to HER2-directed drugs using survivin antagonists.     

Estrogen Receptor and HER2 Status on Disseminated Tumor Cells and Primary Tumor in Patients with Early Breast Cancer

BACKGROUND: We evaluated both estrogen receptor (ER) and human epidermal growth factor receptor 2 (HER2) status on disseminated tumor cells (DTCs) in the bone marrow of 54 patients with early breast cancer and compared these with the corresponding primary tumor (PT). MATERIALS AND METHODS: Bone marrow aspirates were obtained at the time of first surgery, and ER and HER2 status on DTCs was assessed simultaneously by immunocytochemistry using a triple fluorescence staining method. RESULTS: The median number of DTCs was 13 (range 1-95). The concordance rate between ER status on DTC and PT was 74%. Patients with an ER-positive PT were significantly more likely to have at least one ER-positive DTC (34 out of 42) than patients with an ER-negative PT (6 out of 12; P = .031). Thirty-nine (93%) of the 42 patients with ER-positive PT had at least one ER-negative DTC. The concordance rate between HER2 status on DTC and PT was 52%. The probability of having at least one HER2-positive DTC was not related to the HER2 status of the PT (P = 0.56). Twenty-two (46%) of the 48 patients with a HER2-negative PT had at least one HER2-positive DTC. All the six patients with a HER2-positive PT had at least one HER2-negative DTC. CONCLUSION: Taken together, our study confirms that ER and/or HER2 status may differ between DTC and PT. This discordance could be important for patients lacking ER or HER2 expression on the PT but showing ER-positive or HER2-positive DTC because they might benefit from an endocrine and/or HER2-targeted therapy.     

The HSP-RTK-Akt axis mediates acquired resistance to Ganetespib in HER2-positive breast cancer

Breast cancer is the leading cause of cancer-related death in women worldwide. Human epidermal growth factor receptor 2 (HER2)-positive subtype comprises 20% of sporadic breast cancers and is an aggressive disease. While targeted therapies have greatly improved its management, primary and acquired resistance remain a major roadblock to making it a curable malignancy. Ganetespib, an Hsp90 (Heat shock protein 90) small molecule inhibitor, shows preferential efficacy in HER2-positive breast cancer, including therapy-refractory cases, and has an excellent safety profile in ongoing clinical trials (38 in total, six on breast cancer). However, Ganetespib itself evokes acquired resistance, which is a significant obstacle to its clinical advancement. Here, we show that Ganetespib potently, albeit temporarily, suppresses HER2-positive breast cancer in genetic mouse models, but the animals eventually succumb via acquired resistance. We found that Ganetespib-resistant tumors upregulate several compensatory HSPs, as well as a wide network of phospho-activated receptor tyrosine kinases (RTKs), many of which are HSP clients. Downstream of p-RTKs, the MAPK pathway remains suppressed in the resistant tumors, as is HER2 itself. In contrast, the p-RTK effector Akt is stabilized and phospho-activated. Notably, pharmacological inhibition of Akt significantly delays acquired Ganetespib resistance, by 50%. These data establish Akt as a unifying actionable node downstream of the broadly upregulated HSP/p-RTK resistance program and suggests that Akt co-targeting with Ganetespib may be a superior therapeutic strategy in the clinic.Subject terms: Breast cancer, Cancer therapeutic resistance     

Correlation of HER2, p95HER2 and HER3 Expression and Treatment Outcome of Lapatinib plus Capecitabine in her2-Positive Metastatic Breast Cancer

Background

Lapatinib plus capecitabine is an effective treatment option for trastuzumab-refractory HER2-positive metastatic breast cancer. We have investigated the correlation between quantitative measures of HER2, p95HER2, and HER3 and treatment outcomes using lapatinib and capecitabine.

Methods

Total HER2 (H2T), p95HER2 (p95), and total HER3 (H3T) expression were quantified in formalin-fixed paraffin-embedded samples using the VeraTag assays. Patients received lapatinib and capecitabine treatment following trastuzumab failure according to the Lapatinib Expanded Access Program. The association between the protein expression levels and clinical outcomes was analyzed.

Results

A total of 52 patients were evaluable. H2T level was significantly higher in responders (median 93.49 in partial response, 47.66 in stable disease, and 17.27 in progressive disease; p = 0.020). Longer time-to-progression (TTP) was observed in patients with high H2T [p = 0.018, median 5.2 months in high (>14.95) vs. 1.8 in low (<14.95)] and high H3T [p = 0.017, median 5.0 months in high (>0.605) vs. 2.2 in low (<0.605)]. Patients having both high H2T and high H3T had significantly longer TTP [adjusted hazard ratio (HR) 0.38 (95% CI 0.20–0.73), p = 0.004] and overall survival [adjusted HR 0.46 (95% CI 0.24–0.89), p = 0.020]. No significant association between p95 and response or survival was observed.

Conclusions

These data suggest a correlation between high HER2 and high HER3 expression and treatment outcome, while no significant difference was observed between clinical outcome and p95 expression level in this cohort of HER2-positive, trastuzumab-refractory metastatic breast cancer patients treated with lapatinib and capecitabine.     

The Clinical Efficacy and Cardiotoxicity of Fixed-Dose Monthly Trastuzumab in HER2-Positive Breast Cancer: A Single Institutional Analysis

Objective

Trastuzumab-containing treatment regimens have been shown to improve survival outcomes in HER2-positive breast cancer (BC). It is much easier to infuse a fixed one-vial dose to every patient on a regular schedule in the general clinical setting. The aims of this study were evaluating the efficacy of a 440 mg fixed-dose of trastuzumab administered on a monthly infusion schedule, and the risk factors for cardiac events.

Patients and methods

We retrospectively reviewed data from 300 HER2-positive BC patients in our institute: 208 were early-stage BC patients undergoing adjuvant trastuzumab treatment, and 92 were metastatic BC patients treated with trastuzumab infusions until disease progression. There were 181 patients receiving regular trastuzumab infusions every 3 weeks (Q3W; 8 mg/kg loading dose followed by 6 mg/kg every 3 weeks), and the other 119 patients were treated monthly with a fixed 440 mg dose (QM; fixed 440 mg every 4 weeks).

Results

The medians of progression-free survival (PFS) and overall survival (OS) in the adjuvant setting were not reached in both treatment groups. In the metastatic setting, there was no significant difference between groups in PFS or OS. The median time to significant cardiovascular (CV) dysfunction was 4.54 months. The incidence of congestive heart failure requiring medication in our cohort was 3.4%.

Conclusion

In our study, we found that fixed-dose monthly trastuzumab was feasible and effective. In addition, the CV risk was not higher with the fixed-dose protocol. This treatment modality could lower the cost and was easier to implement in clinical practice. Larger prospective randomized studies with longer-term follow up are needed to confirm our results.     

Effective suppression of tumour cells by oligoclonal HER2-targeted delivery of liposomal doxorubicin

Synergistic effect of combined antibodies targeting distinct epitopes of a particular tumour antigen has encouraged some clinical trial studies and is now considered as an effective platform for cancer therapy. Providing several advantages over conventional antibodies, variable domain of heavy chain of heavy chain antibodies (V_HH) is now major tools in diagnostic and therapeutic applications. Active targeting of liposomal drugs is a promising strategy, resulting in enhanced binding and improved cytotoxicity of tumour cells. In the present study, we produced four anti-HER2 recombinant VHHs and purified them via native and refolding method. ELISA and flow cytometry analysis confirmed almost identical function of VHHs in refolded and native states. Using a mixture of four purified VHHs, PEGylated liposomal doxorubicin was targeted against HER2-overexpressing cells. The drug release was analyzed at pH 7.4, 6.4 and 5.5 and dynamic light-scattering detector and TEM micrograph was applied to characterize the produced nanoparticles. The binding efficiency of these nanoparticles to BT474 and SKBR3 as HER2-positive and MCF10A as HER2-negative cell line was examined by flow cytometry. Our results indicated effective encapsulation of about 94% of the total drug in immunoliposomes. Flow cytometry results verified receptor-specific binding of targeted liposomes to SKBR3 and BT474 cell lines and more efficient binding was observed for liposomes conjugated with oligoclonal VHHs mixture compared with monoclonal VHH-targeted liposomes. Oligoclonal nanoparticles also showed more cytotoxicity compared with non-targeted liposomes against HER2-positive tumour cells. Oligoclonal targeting of liposomes was represented as a promising strategy for the treatment of HER2-overexpressing breast cancers.     

Cbl induced ubiquitination of HER2 mediate immune escape from HER2-targeted CAR-T

Breast cancer (BC) with high HER2 expression has higher recurrence rate and worse prognosis, and its immunotherapy is promising. Based on the high expression of HER2, develop Chimeric Antigen Receptor T-cell (CAR-T) and PDL-1 immunotherapy, and study the molecular pathways of related immune cells and recurrence. HER2-CAR-T cells were constructed using retroviruses, and their specific recognition and immune effects on HER2+ BC cells were verified by in vivo and in vitro experiments. PDL-1 was used as adjuvant immunotherapy, knocking down PDL-1 in tumor cells or dendritic cells, or depleted macrophages to study immune pathways. The negative regulation of HER2 by cbl was determined by IP, ubiquitination experiments, and segmented plasmids, elucidating the molecular mechanism of HER2+ BC recurrence after immunotherapy. HER2-CAR-T specifically recognizes HER2-positive tumor cells and inhibits tumor growth in vivo and in vitro, and anti-PDL1 treatment enhances the therapeutic effect of HER2-CAR-T on tumors. HER2-CART therapy eradicated solid tumors after PDL1 knockdown in dendritic cells. Immunotherapy of relapsed tumors lost HER2 expression by upregulating cbl. HER2-CAR-T shows specific recognition of HER2+ cells and can mediate immune response therapy with the cooperation of PDL-1.