HER2-overexpressing Breast Cancer Patients Research Articles

Safety of adjuvant trastuzumab for HER-2-overexpressing elderly breast cancer patients: a multicenter cohort study

For targeting anti-HER-2, trastuzumab-incorporated chemotherapy is the standard for HER-2-overexpressing breast cancer in adjuvant settings. But there are few data on trastuzumab in elderly patients. We evaluated the incidence of adverse events among an elderly population of trastuzumab-treated HER-2-positive breast cancer patients in adjuvant settings. Data on 39 elderly HER-2 overexpressing breast cancer patients treated with both curative surgery and adjuvant trastuzumab were retrospectively collected from a Japanese multicenter study. The loading dose was 8mg/kg body weight, and the maintenance dose was 6mg/kg every 3weeks; or the loading dose was 4mg/kg followed by 2mg/kg weekly as maintenance. After a median follow-up of 20.0(2.4-53.9)months, a total of 32 patients (82.1%) completed 1-year trastuzumab treatment. The median treatment duration was 12.0months (range 2-12; mean 10.5). Adverse events occurred in 11 patients (28.2%). Four (10.2%) discontinued or interrupted treatment after experiencing toxicity. One patient died because of interstitial pneumonia. Three patients (7.7%) had congestive heart failure (CHF), one of whom had a history of angina. Three patients (7.7%) had a lower left ventricular ejection fraction (LVEF), and brain natriuretic peptide elevation was totally observed in three patients (7.7%). Three patients with lower LVEF had received chemotherapy containing doxorubicin before trastuzumab. Of the three patients, two discontinued therapy because of CHF, but all recovered with proper medication containing a diuretic agent. Elderly patients tolerated trastuzumab well, although careful management is needed.

Abstract 1737: Overcoming trastuzumab resistance with the irreversible Pan-HER inhibitor neratinib

Abstract Overexpression of HER2 is seen in 15-20% of breast cancer and is a predictor of poor prognosis. Trastuzumab, a monoclonal antibody to the ECD of the HER2 receptor, has been shown to increase survival in patients especially in combination with chemotherapy. However, a significant number of patients do not respond to trastuzumab treatment and resistance develops in those given trastuzumab as a monotherapy. The purpose of this study was to investigate whether the small molecule irreversible tyrosine kinase inhibitor neratinib (HKI-272) could be used to overcome resistance in trastuzumab resistant BT474 and SKBR3 cell lines and to look at the effects of neratinib on trastuzumab naive cell lines. The effects of acute trastuzumab, neratinib, and trastuzumab and neratinib combination treatments were investigated in SKBR3 and BT474 cells. It has already been established that trastuzumab does not abolish pHER2 expression and this has been implicated in trastuzumab resistance. Western blotting showed an increase in pHER2 and pERK with acute trastuzumab treatment. Conversely, acute neratinib treatment alone and in combination with trastuzumab reduced pERK and pHER2 expression. Furthermore, although acute treatment with trastuzumab decreased the expression of pHER3 and pAKT, the combination of neratinib with trastuzumab gave a much greater decrease in expression. Fluorescence microscopy was also performed on both the resistant and native SKBR3 cells after acute trastuzumab, neratinib and combination treatments. Trastuzumab treatment increased pHER2 membrane localisation in both native and resistant cells in a dose dependent manner, whilst neratinib treatment or its combination with trastuzumab reduced membrane pHER2. Cell viability experiments on BT474 and SKBR3 cells showed that neratinib treatment was much more effective at reducing cell viability than trastuzumab(p=0.0078, p=0.0499) and that combined trastuzumab and neratinib treatment was more effective at reducing cell viability than neratinib alone (p=0.0028, p=0.0148). In the trastuzumab resistant SKBR3 and BT474 cells, withdrawal of trastuzumab lead to an increase in cell viability. However, neratinib treatment was able to reverse trastuzumab resistance and significantly reduce cell viability (p=0.0022, p=0.0087). Furthermore, combined treatment with trastuzumab and neratinib was more effective at reducing cell viability than neratinib alone(p=0.0087, p=0.0260) suggesting that trastuzumab treatment should be continued even when resistance develops. These results showed that the combined treatment with neratinib and trastuzumab was more effective in the inhibition of pHER2, pHER3, pAkt and pERK, and led to a greater decrease in cell viability than trastuzumab treatment alone. We would therefore recommend neratinib to be used in combination with trastuzumab in both trastuzumab naive and resistant HER2 over-expressing breast cancer patients. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1737. doi:10.1158/1538-7445.AM2011-1737

Circulating fatty acid synthase: an exploratory biomarker to predict efficacy of the dual HER1/HER2 tyrosine kinase inhibitor lapatinib

In the previous issue of Breast Cancer Research, Jin and colleagues [1] demonstrated that the lipogenic enzyme fatty acid synthase (FASN) is phosphorylated when it is in complex with the tyrosine kinase receptor HER2. HER2-dependent activating phosphorylation of FASN was related to tumor progression and was sensitive to the dual HER1/HER2 tyrosine kinase inhibitor lapatinib [1]. Adding to knowledge of the therapeutic value of the phosphorylation status of FASN in HER2-driven breast cancer (BC), we now provide experimental evidence that the expression status of FASN in the extracellular milieu (that is, extracellular FASN) may function as a novel biomarker that distinctively predicts molecular functioning of lapatinib. AMP-activated protein kinase (AMPK)-activating drugs, by mimicking an elevated AMP/ATP ratio in BC cells, drastically augment the release of extracellular FASN in HER2-positive BC cells [2]. Lapatinib-induced deprivation of tumor cell energy activates AMPK to trigger an entire cascade of metabolic events, including suppression of FASN expression and activity [1,3]. We hypothesized that a differential ability to initiate AMPK-sensed metabolic stress responses may provide information about the efficacy of HER-targeting drugs via changes in the extracellular FASN status. Enzyme-linked immunosorbent assay (ELISA)-based quantitative analyses revealed that lapatinib treatment drastically enhanced extracellular FASN concentration (by at least 8.0-fold) (Figure ​(Figure1a).1a). Immunoblotting assessment of AMPK phosphorylation at Thr172 confirmed that lapatinib treatment induced a strong activation of AMPK (Figure ​(Figure1b).1b). A weak but detectable upregulation of PP-AMPKThr172 was observed upon treatment with gefitinib. Trastuzumab, cetuximab, and erlotinib - all of which are unable to promote FASN release - failed to activate AMPK. AMPK knockdown using short interfering RNA (siRNA) transfection [2] fully prevented lapatinib-induced FASN release (Figure S1). Immunoblotting and cell imaging analyses confirmed that FASN was depleted from the cytosol of lapatinib-treated HER2 overexpressors and accumulated in their extracellular milieu (Figure S1). Figure 1 Lapatinib's molecular functioning involves AMPK-dependent release of extracellular fatty acid synthase (FASN). (a) HER1 or HER2 inhibitors (or both) differentially regulate extracellular expression of FASN. FASN concentration in cell culture supernatants ... Treatment with lapatinib dramatically increased FASN release (by approximately 17 times) in lapatinib-responsive SKBR3 TzbR cells (Figure ​(Figure1c),1c), which were selected for long-term outgrowth in trastuzumab-containing culture medium. Extracellular FASN remained unaltered in response to trastuzumab or lapatinib in JIMT-1 BC cells, which exhibit de novo cross-refractoriness to multiple HER1/2-targeted therapies (Figure ​(Figure1c).1c). Lapatinib treatment significantly activated AMPK and promoted an enormous accumulation of extracellular FASN in lapatinib-hypersensitive MCF-7/HER2 cells (Figure ​(Figure1d).1d). Equimolar concentrations of lapatinib failed to activate AMPK or to alter FASN release into the extracellular milieu of MCF-7/HER2 LapR cells, which were obtained by continuously subculturing parental MCF-7/HER2 cells with high-dose lapatinib. High levels of circulating FASN can be found in peripheral blood of HER2-overexpressing BC patients [4]. The exclusive ability of lapatinib to actively promote the extracellular release of FASN via AMPK-sensed energy depletion in metabolically demanding HER2-driven BC cell growth might provide a molecular rationale to evaluate the predictive value of circulating FASN in HER2-positive BC patients receiving lapatinib.

Phase II clinical trial of liposomal-encapsulated doxorubicin citrate and docetaxel, associated with trastuzumab, as neoadjuvant treatment in stages II and IIIA HER2-overexpressing breast cancer patients. GEICAM 2003-03 study

Background: We previously reported a phase I trial of liposome-encapsulated doxorubicin citrate (LD), docetaxel and trastuzumab as neoadjuvant in stages II and IIIA human epidermal growth factor receptor 2-overexpressing breast cancer patients. This study evaluates the efficacy of this regimen in a phase II trial.Patients and methods: Patients were treated with LD 50 mg/m2 and docetaxel 60 mg/m2 every 21days associated with standard trastuzumab dose and pegfilgrastim support.Results: Fifty-nine patients were enrolled; median age: 48 years (range 24–71 years); premenopausal patients: 36 (61%); 19 patients (32%) presented stage IIIA disease and 40 patients (67%) stage II; histological grades 2–3 tumors: 50 patients (84%) and estrogen receptor–progesterone receptor negative: 28 patients (47%). In all, 27% achieved a pathological complete response in breast and axilla (grade 5—Miller and Payne classification); 15% of patients achieved grade 4. Clinical and radiological response rates were 86% and 81%, respectively. Forty-two patients (71%) underwent breast-conserving surgery. The main grades 3–4 toxic effects were non-febrile neutropenia (29%) and fatigue (8%). Grade 2 left ventricular ejection fraction decline was observed in nine patients. No congestive heart failure was observed.Conclusions: LD plus docetaxel combination associated with trastuzumab as neoadjuvant is active in breast cancer and entails a favorable cardiotoxicity profile. This regimen is a new treatment option in these patients.

Abstract PD07-05: In Situ Immune Response after Neoadjuvant Chemotherapy for Breast Cancer Predicts Survival

Abstract Purpose: Accumulating preclinical evidence suggest that anticancer immune responses contribute to the success of chemotherapy. However, the prognostic value of tumor infiltrating lymphocytes after neoadjuvant chemotherapy for breast cancer remains unknown. We hypothesized that the nature of the immune infiltrate following neoadjuvant chemotherapy would predict patient survival. Patients and Methods: In a series of 111 consecutive HER2 and a series of 51 non HER2 overexpressing breast cancer patients treated by neoadjuvant chemotherapy, we studied by immunohistochemistry tumor infiltration by Foxp3 and CD8 T lymphocytes before and after chemotherapy. Kaplan-Meier analysis and Cox modeling were used to assess relapse-free survival (RFS) and overall survival (OS). A prognostic scoring system using American Joint Committee on Cancer (AJCC) pathologic staging and immunological markers was created. Results: Association of high CD8 and low Foxp3 cell infiltrates after chemotherapy was significantly associated with improved RFS (p=0.02) and OS (p=0.002), and outperformed classical prognostic factors in multivariate analysis. A combined score associating CD8/Foxp3 ratio and pathological AJCC staging isolated a subgroup of patients with a long-term overall survival of 100%. Importantly, this score also identified patients with favorable prognosis in an independent cohort of HER2 negative breast cancer patients. Conclusion: Immunological CD8 and Foxp3 cell infiltrate after treatment is a novel independent prognostic factor of survival in breast cancer patients treated with neoadjuvant chemotherapy. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr PD07-05.

FOXO1A is a target for HER2-overexpressing breast tumors.

Trastuzumab treatment has improved the overall survival of HER2-overexpressing breast cancer patients. However, many of these patients will eventually become resistant to treatment. The mechanisms that contribute to resistance to trastuzumab are unknown. In this study, we tested the hypothesis that targeting of the FKHR transcription factor FOXO1A in HER2-overexpressing breast tumor cells can overcome the trastuzumab resistance in vitro. We have shown that overexpression of HER2 leads to activation of phosphatidylinositol 3-kinase (PI3K)/Akt pathway and subsequent inactivation of FOXO1A in HER2-overexpressing breast cancer cells SKBR3, BT474, and MCF7-HER2. In wild-type SKBR3 and BT474 cells, trastuzumab downregulates active Akt and increases FOXO1A expression that leads to increase in p27(kip1) and decrease in cyclin D1 and finally inhibits cell proliferation. In contrast, the effect of trastuzumab was eliminated by the reduction of FOXO1A in HER2-overexpressing cells with constitutively active Akt1 (SKBR3/AA28 and BT474/AA9). The downregulation of FOXO1A resulted in nuclear export of p27(kip1). Blocking the constitutively active Akt by a specific Akt/protein kinase B signaling inhibitor-2 (API-2) significantly increased FOXO1A expression and rendered the cells more responsive to trastuzumab-induced growth inhibition. Reactivation of FOXO1A by stable or transient transfection also restored the growth-inhibitory effects of trastuzumab in SKBR3/AA28, BT474/AA9, and MCF7-HER2 cells. Knocking down FOXO1A by small interfering RNA resulted in reducing trastuzumab-induced growth inhibition. In summary, trastuzumab can inhibit proliferation of HER2-overexpressing breast cancer cells by reactivating FOXO1A through inhibition of the PI3K/Akt pathway. FOXO1A may therefore serve as a target for HER2-overexpressing breast tumors.

Use of CD8 and Foxp3 immune infiltrates after neoadjuvant chemotherapy to predict survival in HER2-overexpressing breast cancer patients.

10555 Background: The role of tumor-immune infiltrate modifications by chemotherapies in the outcome of breast cancer is unknown. We previously demonstrated that high CD8 infiltrate and absence of Foxp3 cells after primary systemic chemotherapy (PSC) for breast cancer was associated with complete pathological response, the gold standard prognostic factor in this setting (ladoire et al Clin Cancer Res 2008). We investigated the prognostic relevance of Foxp3 and CD8 lymphocyte infiltrates in tumor bed after neoadjuvant chemotherapy in patients with breast cancer in another independent series. Methods: In a series of 111 HER2 overexpressing breast cancer treated with PSC, we studied by immunohistochemistery the infiltration in Foxp3 and CD8 cells after chemotherapy. Kaplan-Meier analysis and Cox regression modeling were used to assess the overall survival and relapse-free survival. Results: Sixty-three patients were treated with docetaxel and trastuzumab, 48 patients were treated with anthracycline-based regimen. A strong positive correlation was observed between immune response and complete pathological response (p=0,0015 Fisher exact Test). Using unvivariate analysis, the presence of a good immune response (defined as a strong infiltration in CD8 combined with a weak infiltrate in Foxp3 cells), was associated with a better relapse-free survival and overall survival in whole population (p=0.0001 and p=0.008 Log Rank Test) but also in both anthracycline and trastuzumab subgroup. Using multivariate Cox analysis, good immunological response (hazard ratio 0.24 [0.11-0.51] and 0.29 [0.12-0.7]) and trastuzumab treatment (hazard ratio 0.51 [0.26-0.98] and 0.09 [0.02-0.38]) were independently associated with better relapse-free survival and overall survival. Conclusions: Immunological CD8 and Foxp3 infiltrate after PSC is as a new independent prognostic factor of relapse and survival in breast cancer patients with HER2 overexpressing tumors. The immunological scoring systems compared favorably to the previous clinical gold standard (pathological complete response). Future works are required for a prospective validation of these scoring systems. No significant financial relationships to disclose.

Abstract 612: FOXO1A is a target for HER2 overexpressing breast tumors

Abstract Trastuzumab treatment has improved the overall survival of HER2 overexpressing breast cancer patients. However, many of these patients will eventually become resistant to treatment. It is unclear what mechanisms may contribute to resistance to Trastuzumab. In this study we have tested the hypothesis that targeting of the FKHR transcription factor FOXO1A in HER2 overexpressing breast tumor cells, can overcome the Trastuzumab resistance in vitro. We have demonstrated that overexpression of HER2 leads to activation of PI3K/Akt pathway and subsequent inactivation of FOXO1A in HER2 overexpressing breast cancer cells, SKBR3. In wildtype SKBR3 cells, Trastuzumab downregulates active Akt (pAkt) and increases FOXO1A expression that leads to increase in p27kip1, and decrease in cyclin D1, and finally inhibits SKBR3 cell proliferation. In contrast, the effect of Trastuzumab was eliminated by the reduction of FOXO1A in HER2 overexpressing cells with constitutively active Akt1 (Clone SKBR3/AA28). The down-regulation of FOXO1A in SKBR3/AA28 resulted in nuclear export of p27kip1. Blocking the constitutively active Akt by a specific Akt/protein kinase B signaling inhibitor-2 (API-2) significantly increased FOXO1A expression and rendered the SKBR3/AA28 cells more responsive to Trastuzumab induced growth inhibition. Re-activation of FOXO1A by stable transfection or transient transfection also restored the growth inhibitory effects of Trastuzumab in SKBR3/AA28 cells. In summary, Trastuzumab can inhibit proliferation of HER2 overexpressing breast cancer cells by re-activating FOXO1A through inhibition the PI3K/Akt pathway. FOXO1A may therefore serve as a target for HER2 overexpressing breast tumors, and its activation or increased expression may overcome resistance to Trastuzumab treatment. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 612.

Presence of Foxp3 expression in tumor cells predicts better survival in HER2-overexpressing breast cancer patients treated with neoadjuvant chemotherapy

The Forkhead Box Protein 3 is highly expressed not only in regulatory T cells, but also in tumor cells, acting as a transcriptional repressor of breast oncogenes including HER2. We investigated the prognostic significance of Foxp3 expression in cancer cells in a large cohort of patients with HER2-overexpressing breast carcinoma treated with neoadjuvant chemotherapy. Foxp3-positive tumor cells were detected by immunohistochemistry in 103 patients with primary invasive HER2-overexpressing breast carcinoma, and treated with neoadjuvant chemotherapy, with or without trastuzumab. Kaplan-Meier analysis and Cox regression model were used to assess relapse-free and overall survival, respectively, and according to the presence or the absence of Foxp3 expression in tumor cells. Breast cancer cells were Foxp3+ in 57% of tumors. Foxp3 expression in breast cancer cells was associated with better relapse-free (P = 0.005) and overall survival (P = 0.03). By multivariate analysis, the presence of Foxp3+ tumor cells produced an independent prognostic factor for both better relapse-free (P = 0.006) and overall survival (P = 0.03). These findings indicate that the presence of Foxp3+ tumor cells represents a new independent prognostic factor of improved outcome in HER2-overexpressing breast carcinoma, which could help identify high-risk patients for additional therapies after neoadjuvant chemotherapy.

MIC A/B Protein Expression Associates with Trastuzumab-Resistant Breast Cancer Cells Leading to Effective Immunotherapy by Cytokine Induced Killer Cells.

Abstract 4092Poster Board III-1027Citokine Induced Killer (CIK) cells are a heterogenous subset of T lymphocytes sharing phenotype and functional properties with natural killer (NK) cells. CIK cells can be massively ex-vivo expanded and are capable of antitumor activity in both hematological and solid malignancies. The antitumor activity of CIK cells is classically MHC-unrestricted and mostly mediated by the interaction of CIKs' membrane receptor NKG2D with its ligands on tumor cells. The main ligand for NKG2D is MHC class I-related chain (MIC) A/B. The expression of this protein is potentially induced by pathological stimuli and is reported to be associated to some malignant phenotypes. The presence of MIC A/B on tumor targets is crucial for an effective killing by CIK cells and its accurate evaluation might help identifying the tumors, and potentially the patients, more sensitive to a CIK based immunotherapy approach.Trastuzumab, is a humanized monoclonal antibody directed against the extracellular portion of the tyrosine kinase HER2. Although Trastuzumab has been successfully used in HER2-overexpressing breast cancer (BC) patients, resistance is a frequent problem that culminates in treatment failure. The scarsity of treatment options for resistant patients renders crucial the exploitation of new potential targets for tumor treatment.In this context we hypothesized that MIC A/B expression might be associated with the acquisition of aggressive characteristics by BC cells, like the emersion of resistance to Trastuzumab treatment.Flow-cytometry analysis showed that the expression of MIC A/B was virtually absent on HER2-overexpressing BC cells (SKBR3). These cells showed a high sensitivity to treatment with Trastuzumab in vitro, detected through cell proliferation test in soft agar and bioluminescent essays for ATP release. Similarly to what happens in the clinic, a prolonged treatment (> 6 months), determined the selection of cell clones resistant to Trastuzumab exposure. This event was found to be associated with the acquisition of a high expression of MIC A/B on cancer cells' membrane (> 95%). A high expression of MIC A/B (>95%) was confirmed also on a different BC cell line (JIMT-1) that is characterized by a primitive resistance to Trastuzumab. As hypothesized, CIK cells, generated from healthy donors, efficiently killed Trastuzumab-resistant (TR), MIC A/B positive, BC cells (86%, 85%, 81% and 68% of specific killing at a 40:1, 20:1, 10:1 and 5:1 effector/target ratio respectively) while were minimally effective against MIC A/B negative, Trastuzumab-sensitive (TS), BC cells (30%, 23%, 15% and 11% of specific killing at a 40:1, 20:1, 10:1 and 5:1 effector/target ratio respectively, p < 0.0001). The test was performed by staining target cells with Carboxyfluorescein Succinimidy ester (CFSE) and co-culturing them with CIKs at different ratios; data were analyzed after 4 and 12 hours by flow cytometry (Fig.1).Our data describe for the first time the association of MIC A/B upregulation on HER2 overexpressing BC cells and Trastuzumab resistance. This biological event induces the susceptibility of cancer cells to tumor killing operated by CIK cells. If confirmed on breast cancer tissues, our data might provide a rationale for CIK based immunotherapy in HER2 overexpressing breast cancer patients developing clinical resistance to Trastuzumab. Additional studies will investigate the possible molecular links between Trastuzumab resistance and MIC A/B expression.CIK vs Trastuzumab sensitive BCCIK vs Trastuzumab resistant BCP< 0.0001 [Display omitted] Disclosures:No relevant conflicts of interest to declare.

Hormone Receptor Expression Is Associated With a Unique Pattern of Metastatic Spread and Increased Survival Among HER2-Overexpressing Breast Cancer Patients

HER2/neu (HER2) overexpression occurs in approximately 20% of breast cancers and is associated with aggressive disease. Although a significant number of HER2-positive tumors also express hormone receptors (HR), the effects HR expression has on clinical characteristics, including response to trastuzumab among HER2-positive breast cancer, has not been elucidated yet. A retrospective analysis of consecutive metastatic HER2-positive breast cancer patients was conducted in 2 medical centers. Associations between hormone receptors expression and clinical variables, and metastatic spread pattern and survival were studied. The study population included 137 metastatic HER2-positive breast cancer patients, 56 of them were HR-positive and 81 were HR-negative. No significant differences between the 2 groups were found for demographic and clinical characteristics, including age, stage at diagnosis, tumor histology, and grade. Similar response rate to trastuzumab was observed in both study groups. Significantly, longer, median, disease-free, and overall survival was noted among the HR-positive patients. Patients in the HR-negative group had significantly more liver metastases, a trend for more brain metastases, and less bone metastases. There was a strong trend for more visceral metastases in the HR-negative group. Our results suggest an important role for HR expression in modulating metastases predilection and disease progression in HER2-positive breast cancer.

MTOR inhibitors and the anti-diabetic biguanide metformin: new insights into the molecular management of breast cancer resistance to the HER2 tyrosine kinase inhibitor lapatinib (Tykerb®)

The small molecule HER2 tyrosine kinase inhibitor (TKI) lapatinib (Tykerb) is approved for the therapy of patients with HER2-positive breast carcinomas who have progressed on trastuzumab (Herceptin). Unfortunately, the efficacy of this HER2 TKI is limited by both primary (inherent) and acquired resistance, the latter typically occurring within 12 months of starting therapy. One of the key factors limiting our understanding of the mechanisms involved in lapatinib resistance is the lack of published preclinical models. We herein review lapatinib-refractory models recently developed at the bench and the survival pathways discovered. As hyperactivation of the pharmacologically targetable PI3K/mTOR/p70S6K1 axis appears to be central to the occurrence of lapatinib resistance, preclinical data showing enhanced antitumour effects when combining lapatinib with mTOR inhibitors (e.g., rapamycin analogues and NVP-BEZ235) highlight the importance of translational work to yield clinically useful regimens capable of delaying or treating lapatinib resistance. The unexpected ability of the anti-type II diabetes drug metformin to inactivate mTOR and decrease p70S6K1 activity further reveals that this biguanide, generally considered non-toxic and remarkably inexpensive, might be considered for new combinatorial lapatinib-based protocols in HER2-overexpressing breast cancer patients.

Trastuzumab-mediated cardiac dysfunction (CDx) outside of clinical trials: Single Asian center experience

e20732 Background: Trastuzumab is an effective drug for the treatment of HER2 positive breast cancer (BC) and CDx has been reported as a major toxicity. The purpose of our study was to investigate the trastuzumab mediated CDx in practice setting and the treatment outcome at single Asian center. Methods: We retrospectively analyzed 181 HER2-overexpressing BC patients (pts) who were treated with trastuzumab containing regimen between January 2005 and December 2007 at Seoul National University Hospital. We investigated the incidence of CDx and the degree of reversibility using echocardiography (EchoCG) and identify the risk factors to predict CDx. Results: Among 181 patients (pts), 112 were treated for palliative purpose and 139 had previously received anthracycline-based chemotherapy. Baseline EchoCG results were available in 129 pts (median age 47; range 25–79) and median left ventricular ejection fraction (LVEF) was 59% (range 45–70). Median follow-up duration was 21 months. LVEF decreased more than 5% points in 37 out of 129 (28.6%). According to the national cancer institute common terminology criteria for adverse events, grade (G) 2 and G 3/4 CDx developed in 4 (3.1%) and 8 (6.2%) pts respectively. Seven pts experienced symptomatic heart failure (HF). 3 among 5 pts who experienced discontinuation of trastuzumab could resume trastuzumab after median 146 (range 94–163) days of discontinuation. Median LVEF was 54% (range 45–63) at baseline in pts who experienced G2–4 CDx and deceased to 45% (range 30–49) after median 175 (range 65–415) days of trastuzumab treatment. HF treatment was initiated in 9 pts. 4 pts received angiotensin converting enzyme inhibitors (ACEI), 3 pts angiotensin receptor blockers (ARB) and 2 pts ACEI or ARB with diuretics. Occurrence of CDx (G2–4) was associated with higher anthracycline cumulative doses (p=0.039) and lower baseline LVEF (p=0.003). The incidence of symptomatic HF was related with past medical history such as hypertension (p=0.019) and lower baseline LVEF (p=0.005). Among the pts who had G2–4 CDx, LVEF was restored to 54% (range 40–59) which was similar to baseline at median 187 (range 56–477) days after the diagnosis of CDx. Conclusions: The majority pts with trastuzumab-mediated CDx were asymptomatic and LVEF could be reversible. No significant financial relationships to disclose.

Phase I clinical trial of liposomal-encapsulated doxorubicin citrate and docetaxel, associated with trastuzumab, as neo-adjuvant treatment in stages II and IIIA, HER2-overexpressing breast cancer patients. GEICAM 2003-03 study

BackgroundWe carried out a phase I clinical trial to establish the dose-limiting toxicity (DLT) and the maximum tolerated dose (MTD) of the combination of liposome-encapsulated doxorubicin citrate (LD) and docetaxel in breast cancer patients. Patients and methodsPatients with HER-2-overexpressing stages II and IIIA breast cancers were treated in different dose cohorts of three patients. The MTD cohort was expanded up to six patients. The patients received LD and docetaxel every 21 days, plus weekly trastuzumab, with pegfilgrastim support. ResultsA total of 20 patients were enrolled, 18 of them being assessable for toxicity and response. DLTs observed for this combination were diarrhea, fatigue, febrile neutropenia, stomatitis, myalgia, and nonneutropenic infection (pneumonia). LD 50 mg/m2 and docetaxel 60 mg/m2 every 21 days have been the MTD, with no episode of DLT observed. Seven patients developed left ventricular ejection fraction decline (six grade 1 and one grade 2). No interruptions of the treatment were needed as a consequence of cardiac toxicity. Pathologic complete response was achieved in eight patients (44%). ConclusionsThe MTD and recommended dose for phase II trials of LD and docetaxel are 50 and 60 mg/m2, respectively. The achieved results on cardiotoxicity are promising.

Trastuzumab treatment improves brain metastasis outcomes through control and durable prolongation of systemic extracranial disease in HER2-overexpressing breast cancer patients

In patients with human epidermal growth factor receptor-2 (HER2)-overexpressing breast cancer, treatment with trastuzumab has been shown to markedly improve the outcome. We investigated the role of trastuzumab on brain metastasis (BM) in HER2-positive breast cancer patients. From 1999 to 2006, 251 patients were treated with palliative chemotherapy for HER2-positive metastatic breast cancer at Samsung Medical Center. The medical records of these patients were analysed to study the effects of trastuzumab on BM prevalence and outcomes. Patients were grouped according to trastuzumab therapy: pre-T (no trastuzumab therapy) vs post-T (trastuzumab therapy). The development of BM between the two treatment groups was significantly different (37.8% for post-T vs 25.0% for pre-T, P=0.028). Patients who had received trastuzumab had longer times to BM compared with patients who were not treated with trastuzumab (median 15 months for post-T group vs 10 months for pre-T group, P=0.035). Time to death (TTD) from BM was significantly longer in the post-T group than in the pre-T group (median 14.9 vs 4.0 months, P=0.0005). Extracranial disease control at the time of BM, 12 months or more of progression-free survival of extracranial disease and treatment with lapatinib were independent prognostic factors for TTD from BM.

Combination effects of herceptin, pertuzumab and bevacizumab in a HER2-overexpressing breast cancer xenograft model.

Abstract Abstract #4058 Background: The HER2 receptor is overexpressed in 20-25% of breast cancer patients and is associated with poor prognosis. Trastuzumab, a humanized monoclonal antibody directed against the HER2 receptor, used alone or in combination with chemotherapy, has shown significant clinical benefit in improving survival in metastatic patients, as well as improving survival in early breast cancer. However, resistance to trastuzumab often develops within 1 year of treatment initiation. Recent studies have shown that trastuzumab in combination with pertuzumab or bevacizumab may have clinical benefit in selected HER2 overexpressing breast cancer patients. In the present study, we investigated whether blockade of HER homo- and heterodimer pairs in combination with an anti-VEGF, could more effectively inhibit tumor growth in a HER2 overexpressing breast cancer model.&amp;#x2028; Material and Methods: Nude mice bearing subcutaneous BT474 HER2-R (a resistant derivative cell line) xenograft tumors were treated with trastuzumab (T) (10 or 20 mg/kg), pertuzumab (P) (15 mg/kg once weekly after an initial 30 mg/kg loading dose), bevacizumab (B) (5mg/kg), as single agents or in doublets and triplets combination therapies with T at 10 mg/kg. Endpoints include tumor volume, HER signaling, angiogenic biomarkers and occurrence of metastasis.&amp;#x2028; Results: T (at its highest dose) and B, as single courses, showed significant anti-tumor activity as compared with the non-treated group. P or T (at its lowest dose) were not effective at inhibiting tumor growth. Combined treatment with P and B significantly inhibited tumor growth as compared with either agent alone or T alone. Time to tumor progression (tumors reaching 2.5 times baseline size) was 26 days for T + B &amp; T + P, and 30 days for P+B as compared with 15 for P, 20 for H (20mg/kg) and 25 days for B, as single agents. In the mice treated with the triple combination, tumor volumes decreased after treatment initiation achieving a complete tumor regression on day 47 with no tumor regrowth up to day 80. Preliminary mechanistic studies showed that P and T as single agents or in combination caused a decrease of HER2 phosphorylation and downstream AKT activation. No further decrease of HER2 signaling was observed with the triple combination.&amp;#x2028; Discussion: Our results confirm that inhibiting tumour angiogenesis by targeting VEGF has anti-tumor effects. Time to progression was delayed in mice treated with T+P compared with mice treated with a double dose of T, confirming that increasing the dosage of a single anti-HER agent is not as effective as using a combination regimen of inhibitors with different mechanisms of action. Complete tumor regression was achieved when B was combined with P and T at its lower dose, suggesting crosstalk between the VEGF pathway with both the epidermal growth factor receptor (EGFR) and HER2 pathways. Ongoing experiments, IHC and angiogenic biomarker analysis, will provide additional insight into the mechanism of action of T+P+B in this tumor model. Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 4058.

Trastuzumab treatment improves brain metastasis outcomes through control and durable prolongation of systemic extracranial disease in HER2-overexpressing breast cancer patients

Trastuzumab treatment improves brain metastasis outcomes through control and durable prolongation of systemic extracranial disease in HER2-overexpressing breast cancer patients

Continuing trastuzumab beyond disease progression: outcomes analysis in patients with metastatic breast cancer.

IntroductionWe performed a retrospective analysis of HER2-overexpressing metastatic breast cancer patients to describe clinical outcomes of those who, despite progression of the disease (PD), maintained trastuzumab for multiple chemotherapy lines. We also compared survival of these patients with that of those who halted trastuzumab at first PD.MethodsWe identified 101 patients treated between July 2000 and January 2007. Nineteen were still receiving the first-line trastuzumab-based treatment without evidence of PD and were not included in this analysis. Of the remaining 82 patients, 59 retained trastuzumab for one or more additional lines of chemotherapy after PD, according to our institution policy. Twenty-three patients who changed treating institution and stopped trastuzumab at first progression were used as a control group.ResultsFor patients retaining trastuzumab, the median follow-up was 39.6 months. Clinical outcomes showed the typical degradation between first and second lines of therapy which we would expect by halting trastuzumab at first progression. Response rates were 35% and 16% and median times to progression were 7.25 and 5.25 months for the first and second lines of trastuzumab therapy, respectively. The median overall survival (OS) rates were 70 months for patients who retained trastuzumab and 56 months for patients who halted the drug (hazard ratio [HR] 0.87, 95% confidence interval [CI] 0.51 to 1.18; P = 0.52). If we consider OS from the start of trastuzumab therapy, the figures are 53.9 and 34.8 months, respectively (HR 0.78, 95% CI 0.58 to 1.32; P = 0.2).ConclusionA nonstatistically significant trend of improved survival for patients retaining trastuzumab is observed. This is in line with most retrospective analyses and recent randomized data. Retaining trastuzumab after progression is a reasonable option, but further randomized data are warranted to better define its role in comparison with other available options.

Trastuzumab induces gastrointestinal side effects in HER2-overexpressing breast cancer patients

To characterise the gastrointestinal toxicities associated with Trastuzumab administration in HER2-overexpressing breast cancer patients. All patients (n = 46) who received Trastuzumab as a single agent or in conjunction with conventional anti-cancer treatment within the Royal Adelaide Hospital Cancer Centre from 2002-2007 were included in this study. A retrospective analysis of case-notes was conducted to investigate the toxicities associated with Trastuzumab. Trastuzumab as a single agent induced toxicities following 22% of administrations. Gastrointestinal toxicities were observed following 12% of administrations and included nausea and vomiting, diarrhoea, abdominal pain and bloating. However, other prominent toxicities that were not related to the gastrointestinal tract were also observed including fatigue and lung symptoms (10.4%). Elderly patients (> or =60 years) and those with metastatic disease experienced the highest frequency of toxicity. Trastuzumab induces a range of gastrointestinal toxicities in HER2-overexpressing breast cancer patients. These toxicities are separate to those caused by concurrent chemotherapy and/or radiotherapy.

Correlation between NK function and response to trastuzumab in metastatic breast cancer patients

BackgroundTrastuzumab is a monoclonal antibody selectively directed against Her2 and approved for the treatment of Her2 overexpressing breast cancer patients. Its proposed mechanisms of action include mediation of antibody-dependent cellular cytotoxicity (ADCC) by triggering FcγRIII on natural killer (NK) cells. This study addresses the correlation between overall NK function and trastuzumab's clinical activity.Subjects and methodsClinical and immunological responses were assessed in 26 patients receiving trastuzumab monotherapy as maintenance management after chemotherapy (8 mg/kg load and then standard doses of 6 mg/kg every 3 weeks). Cytotoxic activity against the MHC class I-negative standard NK target K562 cell line and HER2-specific ADCC against a trastuzumab-coated Her2-positive SKBR3 cell line were assessed in peripheral blood mononuclear cells (PBMC) harvested after the first standard dose. After six months, seventeen patients were scored as responders and nine as non-responders according to the RECIST criteria, while Progression-Free Survival (PFS) was calculated during a 12 months follow-up.ResultsThe responders had significantly higher levels of both NK and ADCC activities (p < 0.05) that were not different from those of eleven normal controls. The NK activity of the non-responders was significantly (p < 0.05) lower than that of the normal controls. At twelve months, there was a marked correlation between PFS and NK activity only. PFS was significantly longer in patients with high levels of NK activity, whereas its pattern was unrelated to high or low ADCC activity.ConclusionOne of the mechanisms of action of trastuzumab is NK cell-mediated ADCC lysis of the Her2-positve target cell. We show here that its potency is correlated with the short-term response to treatment, whereas longer protection against tumor expansion seems to be mediated by pure NK activity.