Does lapatinib work against HER2-negative breast cancers? (original) (raw)
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Clinical Cancer Research, 2010
Purpose: Acquired endocrine resistance in estrogen receptor (ER)α+/human epidermal growth factor receptor 2-negative (HER2−) breast cancer has been associated with modest adaptive increases in HER2, although exactly how aberrant HER2 signaling affects the ERα pathway is poorly understood. We investigated (a) whether the epidermal growth factor receptor/HER2 inhibitor lapatinib could restore endocrine responsiveness in cell models of acquired endocrine resistance with modest increases in HER2, and (b) the nature of ERα-HER2 cross-talk in this process. Methods: Combination growth studies, ERα transcription, immunoblot, and gene expression assays were conducted in two models of acquired resistance to (a) estrogen deprivation (long-term estrogen-deprived cells) and (b) tamoxifen (long-term tamoxifen-treated cells), and in hormone sensitive controls. Changes in ERα, PgR, and HER2 were assessed in samples from patients treated with tamoxifen. Results: Both cell models of acquired endocrine resistance showed modest adaptive upregulation in HER2, and lapatinib restored endocrine sensitivity in both. The effect of lapatinib on ERα signaling varied markedly depending on the nature of the HER2/ERα cross-talk. In long-term estrogen-deprived cells characterized by enhanced ERα function, lapatinib suppressed ERα genomic activity (as measured by pERSer118, ERα transcriptional activity, and PGR gene expression). In contrast, in long-term tamoxifentreated cells with reduced ERα activation, lapatinib reactivated ERα genomic function. Twenty percent of tamoxifen-resistant patients relapsed with modest increases in HER2 and either suppressed or enhanced ERα/PgR expression. Conclusions: Aberrant GFR signaling can augment or suppress ERα function. Regardless, interrupting the HER2/ERα cross-talk with lapatinib can restore endocrine sensitivity and should be investigated as a therapeutic strategy in combination with endocrine therapy in ERα+/HER2− patients with acquired endocrine resistance. Clin Cancer Res; 16(5); 1486-97. ©2010 AACR.
Molecular Cancer Therapeutics, 2008
Epidermal growth factor receptor (EGFR/ErbB1) and HER2 (ErbB2/neu), members of the ErbB receptor tyrosine kinase family, are frequently overexpressed in breast cancer and are known to drive tumor growth and progression, making them promising targets for cancer therapy. Lapatinib is a selective competitive inhibitor of both the HER2 and EGFR tyrosine kinases. Although lapatinib showed significant activity in patients with HER2-positive breast cancer, the role of EGFR in the response of breast cancer to lapatinib has not been defined. Here, we examined the role of EGFR expression levels in the sensitivity of HER2-overexpressing breast cancer cells to lapatinib. Depletion of EGFR by EGFR small-interfering RNA knockdown did not affect lapatinib sensitivity in these cells, whereas treated HER2 siRNA knockdown cells became more resistant to lapatinib. We conclude that the in vitro activity of lapatinib is not dependent on EGFR expression level in HER2overexpressing breast cancer cells.
Efficacy and Tolerability of Lapatinib in the Management of Breast Cancer
Breast Cancer: Basic and Clinical Research, 2012
Approximately 20%–25% of all breast cancers over express a key cell surface growth factor receptor known as HER2. HER2 plays a key role in cell growth and proliferation and is linked to worse clinical outcomes, making it a logical therapeutic target. The first HER2 targeted drug to be approved by the FDA, was the humanized monoclonal antibody trastuzumab, after it showed improvements in survival in the adjuvant setting, and delayed time to progression in the metastatic setting. Although highly effective, for reasons that are not clear, some patients display resistance to trastuzumab. Lapatinib is an oral, small molecule tyrosine kinase inhibitor, that inhibits both the HER1 ahd HER2 receptors and may be able to overcome trastuzumab resistance. Lapatinib is approved in the second line setting for use in combination with capecitabine or with letrozole. In this review, we will discuss the indications, concerns or any issues with regards to the drug.
Lapatinib-Based Therapy for Women with Advanced/ Metastatic HER2 Positive Breast Cancer
Experimental Oncology, 2015
Background: Lapatinib alone or in combination with other agents, mostly capecitabine is used for patients with advanced/metastatic HER2 positive breast cancer (HER2+BC) after progression on trastuzumab based therapy. Here we report our experience with lapatinib based therapy in this setting. Material and Methods: 67 consecutive patients received lapatinib based therapy. 58 (86.6%) received lapatinib + capecitabine (LC), 7 (10.4%) with other agents and 2 (3.0%) as single agent lapatinib. Data was collected from patients’ records retrospectively. Results: Objective response to lapatinib based therapy in 64 evaluable patients was 64.0% in all patients and 64.0% in patients who received LC. Median progression free survival and overall survival were 10 and 27 months in all patients and 10 and 17 months in patients who received LC, respectively. 16 (24.0%) patients had dose delay > 1 week and/or dose reduction. Conclusion: Lapatinib based therapy is an effective treatment for women wit...
Cancer Research, 2006
Lapatinib (GW572016) is a selective inhibitor of both epidermal growth factor receptor (EGFR) and HER-2 tyrosine kinases. Here, we explore the therapeutic potential of lapatinib by testing its effect on tumor cell growth in a panel of 31 characterized human breast cancer cell lines, including trastuzumab-conditioned HER-2-positive cell lines. We further characterize its activity in combination with trastuzumab and analyze whether EGFR and HER-2 expression or changes induced in the activation of EGFR, HER-2, Raf, AKT, or extracellular signal-regulated kinase (ERK) are markers of drug activity. We report that concentration-dependent antiproliferative effects of lapatinib were seen in all breast cancer cell lines tested but varied significantly between individual cell lines with up to 1,000-fold difference in the IC 50 s (range, 0.010-18.6 Mmol/L). Response to lapatinib was significantly correlated with HER-2 expression and its ability to inhibit HER-2, Raf, AKT, and ERK phosphorylation. Long-term in vivo lapatinib studies were conducted with human breast cancer xenografts in athymic mice. Treatment over 77 days resulted in a sustained and significant reduction in xenograft volume compared with untreated controls. For the combination of lapatinib plus trastuzumab, synergistic drug interactions were observed in four different HER-2-overexpressing cell lines. Moreover, lapatinib retained significant in vitro activity against cell lines selected for long-term outgrowth (>9 months) in trastuzumabcontaining (100 Mg/mL) culture medium. These observations provide a clear biological rationale to test lapatinib as a single agent or in combination with trastuzumab in HER-2overexpressing breast cancer and in patients with clinical resistance to trastuzumab.
Annals of Oncology, 2007
Aberrant activation of some members of human epidermal growth factor receptor (HER) family plays a key role in breast carcinogenesis. Lapatinib is an oral dual tyrosine kinase inhibitor selective for inhibition of epidermal growth factor receptor (EGFR/ErbB1) and HER2/ErbB2. Having more targets, probably its antitumor activity could be more efficient. Clinical data have shown that lapatinib is active in HER2-positive breast cancer as monotherapy, in combination with trastuzumab, and in trastuzumab-resistant patients. Phase I clinical trials have shown also that lapatinib is well tolerated, with mild diarrhea and skin rush as common toxic effects and low incidence of cardiotoxicity. Phase II and III clinical trials' data provide encouraging evidence of the clinical effectiveness of lapatinib in advanced or metastatic breast cancer and for its potential in patients with brain metastases. Interim results from the large, phase III trial in 392 patients showed that in combination with capecitabine lapatinib almost doubled time to progression when compared with capecitabine alone. Several clinical trials that explore the efficacy of lapatinib in combination with conventional chemotherapeutic agents [paclitaxel (Taxol), capecitabine and platinoids], hormonotherapy and other target therapies are ongoing in advanced breast cancer or in neo-adjuvant and adjuvant settings. Our improved understanding of the biology of breast cancer and the use of biomarkers for identification of specific subtypes are allowing us to bring patientspecific novel therapies such as lapatinib to the clinic.
Annals of Oncology, 2008
Background: The efficacy and tolerability of the epidermal growth factor receptor/human epidermal growth factor receptor type 2 (HER2) tyrosine kinase inhibitor lapatinib in refractory metastatic breast cancer were assessed. Patients and methods: In a phase II, open-label study, patients with previously treated HER2-positive (n = 140) or HER2-negative (n = 89) metastatic breast cancer received once-daily oral lapatinib 1500 mg/day. Results: Most (76%) patients had received four or more lines of prior therapy. The response rate in the HER2-positive cohort was 4.3% by investigator assessment and 1.4% by independent assessment. Both assessments established that 6% of HER2-positive patients derived clinical benefit from lapatinib, being progression free for ‡6 months. No objective tumor responses occurred in the HER2-negative cohort. Independent review assessments of median time to progression and median progression-free survival were similar in the HER2-positive and HER2-negative cohorts (9.1 and 7.6 weeks, respectively). All responders exhibited HER2 overexpression (3+ by immunohistochemistry), and five of six responders were HER2 amplified by FISH. Lapatinib-related adverse events, including diarrhea (54%), rash (30%), and nausea (24%), were primarily mild to moderate in severity. Conclusions: Lapatinib monotherapy had modest clinical activity in HER2-positive metastatic breast cancer that progressed on prior trastuzumab regimens. No apparent clinical activity was observed in chemotherapy-refractory, HER2-negative disease.
Journal of Clinical Oncology, 2013
Purpose We previously reported the eradication of human epidermal growth factor receptor 2 (HER2)– amplified human xenografts in mice by inhibition of the HER2 pathway with lapatinib and trastuzumab to block all homo- and heterodimer signaling as well as by blockade of estrogen receptor (ER) when expressed. In this clinical trial, we sought to translate these findings to patients using targeted therapy without chemotherapy. Patients and Methods Women with stages II to III HER2-positive breast cancers were eligible. They received trastuzumab once per week (4 mg/kg loading, then 2 mg/kg) and lapatinib 1000 mg once per day for 12 weeks. Women with ER-positive tumors also received letrozole (plus a luteinizing hormone–releasing hormone [LHRH] agonist if premenopausal). Pathologic response was assessed by ER status. Biopsies were obtained at baseline, weeks 2 and 8, and time of surgery. Results Sixty-six patients were enrolled, and 64 were eligible and evaluable for response. Median tumo...