Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0278488 (metastatic breast cancer)
 7,812 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Targeted therapies by means of compounds that inhibit a specific target molecule represent a new perspective in the treatment of cancer. In contrast to conventional chemotherapy which acts on all dividing cells generating toxic effects and damage of normal tissues, targeted drugs allow to hit, in a more specific manner, subpopulations of cells directly involved in tumor progression. Molecules controlling cell proliferation and death, such as Tyrosine Kinase Receptors (RTKs) for growth factors, are among the best targets for this type of therapeutic approach. Two classes of compounds targeting RTKs are currently used in clinical practice: monoclonal antibodies and tyrosine kinase inhibitors. The era of targeted therapy began with the approval of Trastuzumab, a monoclonal antibody against HER2, for treatment of metastatic breast cancer, and Imatinib, a small tyrosine kinase inhibitor targeting BCR-Abl, in Chronic Myeloid Leukemia. Despite the initial enthusiasm for the efficacy of these treatments, clinicians had to face soon the problem of relapse, as almost invariably cancer patients developed drug resistance, often due to the activation of alternative RTKs pathways. In this view, the rationale at the basis of targeting drugs is radically shifting. In the past, the main effort was aimed at developing highly specific inhibitors acting on single RTKs. Now, there is a general agreement that molecules interfering simultaneously with multiple RTKs might be more effective than single target agents. With the recent approval by FDA of Sorafenib and Sunitinib--targeting VEGFR, PDGFR, FLT-3 and c-Kit--a different scenario has been emerging, where a new generation of anti-cancer drugs, able to inhibit more than one pathway, would probably play a major role.
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PMID:From single- to multi-target drugs in cancer therapy: when aspecificity becomes an advantage. 1828 97

Lapatinib is an oral dual tyrosine kinase inhibitor targeting EGFR1 and EGFR2 (HER2). Phase I trials have shown that lapatinib is well tolerated, with mild diarrhea and skin rush as common adverse effects, and low cardiotoxicity. Phase II and III trials provided evidences on clinical effectiveness in advanced or metastatic breast cancer and potential against brain metastases. Lapatinib is active in combination with trastuzumab and in trastuzumab-resistant patients, moreover it has synergistic action with capecitabine. Several clinical trials are in progress to explore the effectiveness of lapatinib in other combinations and against several tumor types.
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PMID:Lapatinib: a sword with two edges. 1840 20

ErbB-2 overexpression in breast tumors is associated with poor survival. Expression of Notch-1 and its ligand, Jagged-1, is associated with the poorest survival, including ErbB-2-positive tumors. Trastuzumab plus chemotherapy is the standard of care for ErbB-2-positive breast cancer. A proportion of tumors are initially resistant to trastuzumab and acquired resistance to trastuzumab occurs in metastatic breast cancer and is associated with poor prognosis. Thus, we investigated whether Notch-1 contributes to trastuzumab resistance. ErbB-2-positive cells have low Notch transcriptional activity compared to non-overexpressing cells. Trastuzumab or a dual epidermal growth factor receptor (EGFR)/ErbB-2 tyrosine kinase inhibitor (TKI) increased Notch activity by 2- to 6-fold in SKBr3, BT474 and MCF-7/HER2-18 cells. The increase in activity was abrogated by a Notch inhibitor, gamma-secretase inhibitor (GSI) or Notch-1 small-interfering RNA (siRNA). Trastuzumab decreased Notch-1trade mark precursor, increased amount and nuclear accumulation of active Notch-1(IC) and increased expression of targets, Hey1 and Deltex1 mRNAs, and Hes5, Hey1, Hes1 proteins. Importantly, trastuzumab-resistant BT474 cells treated with trastuzumab for 6 months expressed twofold higher Notch-1, twofold higher Hey1, ninefold higher Deltex1 mRNAs and threefold higher Notch-1 and Hes5 proteins, compared to trastuzumab-sensitive BT474 cells. The increase in Hey1 and Deltex1 mRNAs in resistant cells was abrogated by a Notch-1 siRNA. Cell proliferation was inhibited more effectively by trastuzumab or TKI plus a GSI than either agent alone. Decreased Notch-1 by siRNA increased efficacy of trastuzumab in BT474 sensitive cells and restored sensitivity in resistant cells. Trastuzumab plus a GSI increased apoptosis in sensitive cells by 20-30%. A GSI alone was sufficient to increase apoptosis in trastuzumab-resistant BT474 cells by 20%, which increased to 30% with trastuzumab. Notch-1 siRNA alone decreased cell growth by 30% in sensitive and more than 50% in resistant BT474 cells. Furthermore, growth of both trastuzumab sensitive and resistant cells was completely inhibited by combining trastuzumab plus Notch-1 siRNA. More importantly, Notch-1 siRNA or a GSI resensitized trastuzumab-resistant BT474 cells to trastuzumab. These results demonstrate that ErbB-2 overexpression suppresses Notch-1 activity, which can be reversed by trastuzumab or TKI. These results suggest that Notch-1 might play a novel role in resistance to trastuzumab, which could be prevented or reversed by inhibiting Notch-1.
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PMID:ErbB-2 inhibition activates Notch-1 and sensitizes breast cancer cells to a gamma-secretase inhibitor. 1846 55

With improvements in diagnostic and therapeutic options and a corresponding improvement in survival, central nervous system (CNS) metastasis is becoming a more frequent diagnosis in breast cancer patients. It can be assumed that up to 30% of metastatic breast cancer (MBC) patients may experience CNS metastasis during the course of their disease. Moreover, it has been reported that patients with human epidermal growth factor receptor (HER)-2-overexpressing MBC are at a higher risk for CNS involvement. Whereas locoregional treatment modalities such as surgery, radiosurgery, and whole-brain radiotherapy still must be considered as the treatment of first choice, the armamentarium of systemic treatment modalities has been expanded by the introduction of small molecules such as the tyrosine kinase inhibitors. Rather than analyzing the risk factors for the development of CNS metastasis and reviewing the standard diagnostic and therapeutic approaches in patients with CNS involvement, this review focuses specifically on systemic treatment modalities in patients suffering from CNS metastasis from HER-2-overexpressing MBC.
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PMID:Central nervous system metastases in HER-2-overexpressing metastatic breast cancer: a treatment challenge. 1861 87

Leptomeningeal carcinomatosis represents a rare manifestation of metastatic breast cancer (MBC). We herewith report on a patient suffering from HER2 overexpressing MBC who received intrathecal methotrexate and trastuzumab for meningeal carcinomatosis. A 48-year-old woman was diagnosed with breast cancer in December 2002. Following surgery, six cycles of adjuvant FE100C plus irradiation and, subsequently for 1 year, trastuzumab were given. As a result of disseminated metastatic spread in October 2005, the patient received whole-brain radiotherapy for symptomatic central nervous system involvement, and was put on several trastuzumab-based combination regimens (capecitabine, vinorelbine, paclitaxel). In June 2006, the patient developed clinical signs of terminal cone involvement with overflow incontinence and paraparesis of the legs. Immediate radiation led to partial relief from clinical symptoms. Subsequently, the patient was put on the tyrosine kinase inhibitor lapatinib and capecitabine (August to October 2007), but on November 6th the patient suffered again from overflow incontinence and weakness of the legs. Failing to respond to lapatinib, the patient received gemcitabine/cisplatin and, additionally, was recommenced on intravenous trastuzumab. Owing to progressive leptomeningeal disease, the patient received repeated doses of intrathecal methotrexate and trastuzumab. Within 2 weeks and four intrathecal treatments, cerebrospinal fluid cytology showed the absence of tumor cells. Moreover, a striking clinical improvement with resolution of the paraparesis of the legs and overflow incontinence was observed. This case report gives details regarding the clinical course of a breast cancer patient who received intrathecal trastuzumab and methotrexate via lumbar puncture for meningeal carcinomatosis of HER2-overexpressing MBC.
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PMID:Intrathecal trastuzumab (Herceptin) and methotrexate for meningeal carcinomatosis in HER2-overexpressing metastatic breast cancer: a case report. 1869 96

The potential for cardiac toxicity in association with targeted biologic agents was first observed with trastuzumab, a monoclonal antibody that targets the ErbB2/HER2 receptor. In the pivotal trial of trastuzumab in ErbB2-positive metastatic cancer, an increased incidence of serious cardiac events was observed, particularly when trastuzumab was administered in combination with anthracyclines. The ErbB2 receptor is expressed on cardiomyocytes, in addition to tumor tissue, where it exerts a protective effect on cardiac function; thus, interference with ErbB2-signaling may block this protective effect. However, in contrast to anthracycline-induced cardiac toxicity, trastuzumab-related cardiac dysfunction does not appear to increase with cumulative dose or to be associated with ultrastructural changes in the myocardium and is generally reversible. When used in adjuvant regimens for the treatment of ErbB2-positive early-stage breast cancer, trastuzumab has been shown to significantly improve disease-free and overall survival. The incidence of class III/IV congestive heart failure (CHF) ranged from 0.4%-3.8% in the major adjuvant trastuzumab trials. More recently, small-molecule tyrosine kinase inhibitors such as lapatinib have been investigated for the treatment of ErbB2-positive metastatic breast cancer. In a comprehensive analysis of cardiac safety data from all lapatinib trials completed to date, which included 3558 healthy volunteers and patients with a variety of solid cancers on 43 trials, the overall incidence of left ventricular ejection fraction declines was 1.6%, with 0.2% of patients experiencing symptomatic CHF. Risk factors that might predict for cardiac dysfunction with ErbB2-targeted therapy are actively under investigation and will aid in the identification of at-risk populations and in the development of strategies for risk minimization in the future. It is important to note that, while careful cardiac monitoring is required for all patients receiving ErbB2-targeted therapy in any disease setting, the overall impact of these agents on the outcomes of patients with ErbB2-positive breast cancer has been dramatic and positive.
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PMID:Cardiac toxicity of ErbB2-targeted therapies: what do we know? 1877 50

Breast cancer is the second leading cause of cancer death in women. Treatment options for advanced-stage disease, although numerous, remain suboptimal. Lapatinib and ixabepilone are two new agents approved by the United States Food and Drug Administration (FDA) in 2007 for the treatment of locally advanced breast cancer (LABC) or metastatic breast cancer (MBC). When added to the existing endocrine therapies-single--agent cytotoxic therapies and combination chemotherapy regimens--lapatinib and ixabepilone offer potential treatment strategies for disease that has become resistant to trastuzumab and the taxanes, respectively. Lapatinib is an oral dual tyrosine kinase inhibitor against members of the human epidermal growth factor receptor (HER) family (HER1 or epidermal growth factor receptor [EGFR], and HER2). It is indicated for combination therapy with capecitabine for the treatment of patients with HER2-overexpressing LABC or MBC whose disease has progressed after receiving previous treatment with an anthracycline, a taxane, and trastuzumab. Of note, lapatinib is the first FDA-approved tyrosine kinase inhibitor indicated for use in MBC. Ixabepilone, the first FDA-approved analog of the antimicrotubule agent epothilone B, is indicated as monotherapy for the treatment of LABC or MBC in patients whose tumors are refractory or resistant to anthracyclines, taxanes, and capecitabine. It is also indicated in combination with capecitabine for treatment of LABC or MBC that is resistant to anthracycline and taxane. Both lapatinib and ixabepilone are fairly well tolerated. The most common toxicities with lapatinib are diarrhea (65%) and hand-and-foot syndrome (53%), whereas peripheral neuropathy (62%), fatigue (56%), and neutropenia (54%) are most common with ixabepilone. Though the conventional standard end point of overall survival has not yet been assessed in clinical trials, these agents have been shown to improve surrogate markers of clinical benefit: progression-free survival and the related time to progression. Future clinical trials should focus on elucidation of optimal combination or sequential therapies, as well as patient-specific therapies based on tumor characteristics, such as biomarkers and tumor subtypes.
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PMID:Lapatinib and ixabepilone for the treatment of metastatic breast cancer. 1882 21

On March 13, 2007, the U.S. Food and Drug Administration approved lapatinib (Tykerb tablets; GlaxoSmithKline, Philadelphia), an oral, small molecule, dual tyrosine kinase inhibitor of ErbB-2 and ErbB-1, for use in combination with capecitabine for the treatment of patients with human epidermal growth factor receptor (HER)-2-overexpressing metastatic breast cancer who had received prior therapy including an anthracycline, a taxane, and trastuzumab. One multicenter, open-label, randomized trial was submitted. Eligible patients had stage IIIb or IV breast cancer, ErbB-2 overexpression (immunohistochemistry 3+ or 2+ with fluorescence in situ hybridization confirmation), measurable disease, a 0 or 1 Eastern Cooperative Oncology Group performance status score, a cardiac ejection fraction within the institutional normal range, and adequate laboratory function. Patients received either lapatinib (1,250 mg once daily on days 1-21) plus capecitabine (1,000 mg/m(2) every 12 hours on days 1-14) every 21 days or capecitabine alone (1,250 mg/m(2) every 12 hours on days 1-14) every 21 days. The primary endpoint was time to progression (TTP) determined by a blinded independent review panel. After TTP results of a prespecified interim analysis were made available, study enrollment was discontinued (399 patients enrolled). The median TTP was 27.1 versus 18.6 weeks (hazard ratio, 0.57; p = .00013) favoring the lapatinib plus capecitabine arm. Response rates were 23.7% (lapatinib plus capecitabine) versus 13.9% (capecitabine alone). Survival data were not mature. Although the toxicities observed in the lapatinib and capecitabine combination arm were generally similar to those in the capecitabine alone arm, a higher incidence of diarrhea and rash was noted with the combination. Grade 3 or 4 adverse reactions that occurred with a frequency of >5% in patients on the combination arm were diarrhea (13%) and palmar-plantar erythrodysesthesia (12%). There was a 2% incidence of reversible decreased left ventricular function in the combination arm.
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PMID:FDA drug approval summary: lapatinib in combination with capecitabine for previously treated metastatic breast cancer that overexpresses HER-2. 1884 20

It has been over 20 years since the discovery of the human epidermal growth factor receptor 2 (HER2), a tyrosine kinase receptor that is a potent oncoprotein in breast and other cancers and has become an opportune target for therapy. HER2 plays a critical role in normal development, forming homodimers or heterodimers with other HER family members and triggering downstream signaling cascades controlling proliferation, cell survival, and apoptosis. However, amplification of the HER2 gene in cancer cells results in overexpression of HER2 receptors on the cell surface, leading to excessive and dysregulated signaling. HER2-driven signaling also upregulates transcription factors that act on the HER2 promoter, increasing its expression. In breast cancer, HER2 is gene amplified in 20%-25% of primary tumors and is associated with a more aggressive phenotype and poorer prognosis. The key role HER2 plays in tumorigenesis makes it an ideal target for therapy. Trastuzumab, a monoclonal antibody against HER2, inhibits downstream signaling and has proven to be effective against HER2-overexpressing metastatic breast cancer both as a single agent and in combination with chemotherapy. Seminal clinical trial data also show that the use of adjuvant trastuzumab in combination with chemotherapy or as a single agent after chemotherapy significantly increases disease-free and overall survival. Lapatinib, a dual tyrosine kinase inhibitor against HER1 and HER2, has been approved in combination with capecitabine for HER2-overexpressing advanced or metastatic breast cancer, which has progressed following previous anthracycline, taxane, and trastuzumab therapy. Other HER2-targeting strategies are also under active investigation.
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PMID:Unraveling the biologic and clinical complexities of HER2. 1895 52

There is strong clinical evidence that trastuzumab, a monoclonal antibody targeting the human epidermal growth factor receptor (HER) two tyrosine kinase receptor, is an important component of first-line treatment of patients with HER2-positive metastatic breast cancer. In particular the combination with taxanes and vinorelbine has been established. In the preoperative setting inclusion of trastuzumab has significantly increased the pathological complete response rate. Results from large phase III trials evaluating adjuvant therapy in HER2-positive early breast cancer indicate that the addition of trastuzumab to chemotherapy improves disease-free and overall survival. The use of lapatinib, a dual tyrosine kinase inhibitor of both HER1 and HER2, in combination with capecitabine in the second-line treatment of HER2-positive patients with metastatic breast cancer previously treated with trastuzumab has been established. There is modest, but still insufficient, support that the compound passes the blood-brain barrier. Several trials are ongoing both in the adjuvant and metastatic settings and we have to await the results of these to clarify the role of trastuzumab and lapatinib. The clinical problem of tumours developing resistance to HER2-directed therapy is becoming increasingly important. Several issues about optimal selection of patients, prevention of resistance and use of different treatment options are still unresolved. In this article, we summarise the current knowledge on clinical evidence of HER2-directed therapy and the potential mechanisms of underlying resistance, including the possible clinical implications and review new therapeutic options.
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PMID:HER2-targeted therapy in breast cancer. Monoclonal antibodies and tyrosine kinase inhibitors. 1900 49


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