Showing papers on "Tyrosine-kinase inhibitor published in 2011"
TL;DR: Continuous daily administration of sunitinib at a dose of 37.5 mg improved progression-free survival, overall survival, and the objective response rate as compared with placebo among patients with advanced pancreatic neuroendocrine tumors.
Abstract: The multitargeted tyrosine kinase inhibitor sunitinib has shown activity against pancreatic neuroendocrine tumors in preclinical models and phase 1 and 2 trials.
2,192 citations
TL;DR: The role of EGFR mutations in the diagnosis and management of NSCLC is reviewed and tyrosine kinase inhibitors (TKIs) are reviewed, suggesting that initial therapy with a TKI instead of chemotherapy may be the best choice of treatment.
Abstract: Epidermal growth factor receptor (EGFR) is a transmembrane protein with cytoplasmic kinase activity that transduces important growth factor signaling from the extracellular milieu to the cell. Given that more than 60% of non–small cell lung carcinomas (NSCLCs) express EGFR, EGFR has become an important therapeutic target for the treatment of these tumors. Inhibitors that target the kinase domain of EGFR have been developed and are clinically active. More importantly, such tyrosine kinase inhibitors (TKIs) are especially effective in patients whose tumors harbor activating mutations in the tyrosine kinase domain of the EGFR gene. More recent trials have suggested that for advanced NSCLC patients with EGFR mutant tumors, initial therapy with a TKI instead of chemotherapy may be the best choice of treatment. Therefore, mutation testing is mandatory to identify these patients, given that selection based only on clinico-pathologic characteristics is inadequate. We review the role of EGFR mutations in the diagn...
565 citations
TL;DR: In patients with metastatic renal cell carcinoma, sunitinib-associated HTN is associated with improved clinical outcomes without clinically significant increases in HTN-associated adverse events, supporting its viability as an efficacy biomarker.
Abstract: Background
Hypertension (HTN) is an on-target effect of the vascular endothelial growth factor pathway inhibitor, sunitinib. We evaluated the association of sunitinib-induced HTN with antitumor efficacy and HTN-associated adverse events in patients with metastatic renal cell carcinoma.
559 citations
TL;DR: Among patients with acquired resistance to EGFR TKIs, the presence of T790M defines a clinical subset with a relatively favorable prognosis and more indolent progression, which is important both for the clinical care of these patients and for the optimal design and interpretation of clinical trials in this setting.
Abstract: Purpose: Patients with epidermal growth factor receptor (EGFR)-mutant lung adenocarcinoma develop acquired resistance to EGFR tyrosine kinase inhibitors (TKI) after a median of 10 to 16 months. In half of these cases, a second EGFR mutation, T790M, underlies acquired resistance. We undertook this study to examine the clinical course of patients harboring the T790M mutation following progression on TKI. Experimental Design: EGFR-mutant lung cancer patients with acquired resistance to EGFR TKIs were identified as part of a prospective rebiopsy protocol in which postprogression tumor specimens were collected for molecular analysis. Postprogression survival and characteristics of disease progression were compared in patients with and without T790M. Results: We identified T790M in the initial rebiopsy specimens from 58 of 93 patients (62%, 95% CI: 52–72). T790M was more common in biopsies of lung/pleura tissue and lymph nodes than in more distant sites ( P = 0.014). Median postprogression survival was 16 months (interquartile range = 9–29 months); patients with T790M had a significantly longer postprogression survival ( P = 0.036). Patients without T790M more often progressed in a previously uninvolved organ system ( P = 0.014) and exhibited a poorer performance status at time of progression ( P = 0.007). Conclusions: Among patients with acquired resistance to EGFR TKIs, the presence of T790M defines a clinical subset with a relatively favorable prognosis and more indolent progression. Knowledge of T790M status is therefore important both for the clinical care of these patients and for the optimal design and interpretation of clinical trials in this setting. Clin Cancer Res; 17(6); 1616–22. ©2010 AACR .
557 citations
TL;DR: Cabozantinib has an acceptable safety profile and is active in MTC, and may provide clinical benefit by simultaneously targeting multiple pathways of importance in M TC, including MET, VEGFR2, and RET.
Abstract: Purpose XL184 (cabozantinib) is a potent inhibitor of MET, vascular endothelial growth factor receptor 2 (VEGFR2), and RET, with robust antiangiogenic, antitumor, and anti-invasive effects in preclinical models Early observations of clinical benefit in a phase I study of cabozantinib, which included patients with medullary thyroid cancer (MTC), led to expansion of an MTC-enriched cohort, which is the focus of this article Patients and Methods A phase I dose-escalation study of oral cabozantinib was conducted in patients with advanced solid tumors Primary end points included evaluation of safety, pharmacokinetics, and maximum-tolerated dose (MTD) determination Additional end points included RECIST (Response Evaluation Criteria in Solid Tumors) response, pharmacodynamics, RET mutational status, and biomarker analyses Results Eighty-five patients were enrolled, including 37 with MTC The MTD was 175 mg daily Dose-limiting toxicities were grade 3 palmar plantar erythrodysesthesia (PPE), mucositis, and A
501 citations
TL;DR: The clinical utility of using epidermal growth factor receptor (EGFR) mutation testing for patients with advanced non-small-cell lung cancer to predict the benefit of taking a first-line EGFR tyrosine kinase inhibitor (TKI) is addressed.
Abstract: Purpose An American Society of Clinical Oncology (ASCO) provisional clinical opinion (PCO) offers timely clinical direction to ASCO’s membership following publication or presentation of potentially practice-changing data from major studies. This PCO addresses the clinical utility of using epidermal growth factor receptor (EGFR) mutation testing for patients with advanced non–small-cell lung cancer (NSCLC) to predict the benefit of taking a first-line EGFR tyrosine kinase inhibitor (TKI). Clinical Context Patients with EGFR-mutated NSCLC have a significantly higher rate of partial responses to the EGFR TKIs gefitinib and erlotinib. In the United States, approximately 15% of patients with adenocarcinoma of the lung harbor activating EGFR mutations. EGFR mutation testing is widespread at academic medical centers and in some locales in community practice. As of yet, there is no evidence of an overall survival (OS) benefit from selecting treatment based on performing this testing.
487 citations
TL;DR: The clinical data and the effectiveness of gefitinib and erlotinib in NSCLC patients with uncommon EGFR mutations was surveyed, and their associations with EGFR TKIs differed.
Abstract: Purpose: Clinical features of epidermal growth factor receptor (EGFR) mutations, L858R, deletions in exon 19, T790M, and insertions in exon 20, in non–small cell lung cancer (NSCLC) are well known. The clinical significance of other uncommon EGFR mutations, such as their association with the effectiveness of EGFR tyrosine kinase inhibitors (TKI), is not well understood. This study aimed to improve the understanding of these uncommon EGFR mutations of unknown clinical significance. Patients and Methods: Specimens from 1,261 patients were tested for EGFR mutations. We surveyed the clinical data and the effectiveness of gefitinib and erlotinib in NSCLC patients with uncommon EGFR mutations. Results: Of the 1,261 patients, 627 (49.8%) had EGFR mutations. This included 258 patients with deletions in exon 19, 260 patients with L858R, 25 patients with insertions or duplications in exon 20, 6 patients with de novo T790M, and 78 (12.4%) patients with uncommon mutations. Of the 78 patients, 62 received either gefitinib or erlotinib treatment. The response rate of TKIs treatment was 48.4%, and the median progression-free survival (PFS) was 5.0 months. Mutations on G719 and L861 composed a major part (28 of 62) of uncommon mutations, and were associated with a favorable effectiveness of EGFR TKIs (response rate, 57.1%; median PFS, 6.0 months). Mutations other than G719 and L861 led to a worse response to EGFR TKIs (response rate, 20.0%; median PFS, 1.6 months). Conclusions: Uncommon EGFR mutations constituted a distinct part of the whole group of EGFR mutations. Their composition was heterogeneous, and their associations with EGFR TKIs differed. Clin Cancer Res; 17(11); 3812–21. ©2011 AACR .
407 citations
TL;DR: Identification of oncogenes that mediate tumor progression, and trials that monitor their products as biomarkers, might lead to personalized therapy; reagents that interfere with signaling pathways required for HCC progression might be used to treat selected populations, and thereby maximize the efficacy and cost benefit.
402 citations
TL;DR: In patients with EGFR-mutant lung cancer and acquired resistance to epidermal growth factor receptor TKIs, discontinuation of erlotinib or gefitinib before initiation of study treatment is associated with a clinically significant risk of accelerated disease progression.
Abstract: Purpose: Treatment of patients with oncogene-addicted cancers with tyrosine kinase inhibitors (TKI) is biologically and clinically different than with cytotoxic chemotherapy. We have observed that some patients with EGFR- mutant lung cancer and acquired resistance to erlotinib or gefitinib (RECIST progression after initial benefit) have accelerated progression of disease after discontinuation of TKI. To examine this observation and define the course of patients following TKI discontinuation, we systematically evaluated patients enrolled on clinical trials of agents to treat acquired resistance to erlotinib or gefitinib. Methods: We evaluated patients with EGFR -mutant lung cancer who participated in trials for patients with acquired resistance that mandated TKI discontinuation before administration of study therapy. Disease flare was defined as hospitalization or death attributable to disease progression during the washout period. Results: Fourteen of 61 patients (23%; 95% CI: 14–35) experienced a disease flare. The median time to disease flare after TKI discontinuation was 8 days (range 3–21). Factors associated with disease flare included shorter time to progression on initial TKI ( P = 0.002) and the presence of pleural ( P = 0.03) or CNS disease ( P = 0.01). There was no association between disease flare and the presence of T790M at the time of acquired resistance. Conclusions: In patients with EGFR -mutant lung cancer and acquired resistance to epidermal growth factor receptor TKIs, discontinuation of erlotinib or gefitinib before initiation of study treatment is associated with a clinically significant risk of accelerated disease progression. Clinical trials in this patient population must minimize protocol-mandated washout periods. Clin Cancer Res; 17(19); 6298–303. ©2011 AACR .
393 citations
TL;DR: Low BRCA1 levels neutralized the negative effect of the T790M mutation and were associated with longer progression-free survival to erlotinib.
Abstract: Purpose: Advanced non–small-cell lung cancer (NSCLC) patients harboring epidermal growth factor receptor (EGFR) mutations (deletion in exon 19 or L858R) show an impressive progression-free survival of 14 months when treated with erlotinib. However, the presence of EGFR mutations can only imperfectly predict outcome. We hypothesized that progression-free survival could be influenced both by the pretreatment EGFR T790M mutation and by components of DNA repair pathways. Experimental Design: We assessed the T790M mutation in pretreatment diagnostic specimens from 129 erlotinib-treated advanced NSCLC patients with EGFR mutations. The expression of eight genes and two proteins involved in DNA repair and four receptor tyrosine kinases was also examined. Results: The EGFR T790M mutation was observed in 45 of 129 patients (35%). Progression-free survival was 12 months in patients with and 18 months in patients without the T790M mutation ( P = 0.05). Progression-free survival was 27 months in patients with low BRCA1 mRNA levels, 18 months in those with intermediate levels, and 10 months in those with high levels ( P = 0.02). In the multivariate analysis, the presence of the T790M mutation (HR, 4.35; P = 0.001), intermediate BRCA1 levels (HR, 8.19; P P Conclusions: Low BRCA1 levels neutralized the negative effect of the T790M mutation and were associated with longer progression-free survival to erlotinib. We advocate baseline assessment of the T790M mutation and BRCA1 expression to predict outcome and provide alternative individualized treatment to patients based on T790M mutations and BRCA1 expression. Clin Cancer Res; 17(5); 1–9. ©2011 AACR .
298 citations
TL;DR: Activation of PI3K/Akt signaling pathway mediates acquired resistance to sorafenib in HCC, and the combination of sorAFenib and MK-2206, an Akt inhibitor, overcomes the resistance at clinical achievable concentrations.
Abstract: Hepatocellular carcinoma (HCC) is one of the most common potentially lethal human malignancies worldwide. Sorafenib, a tyrosine kinase inhibitor, was recently approved by the United States Food and Drug Administration for HCC. In this study, we established two sorafenib-resistant HCC cell lines from Huh7, a human HCC cell line, by long-term exposure of cells to sorafenib. Sorafenib induced significant apoptosis in Huh7 cells; however, Huh7-R1 and Huh7-R2 showed significant resistance to sorafenib-induced apoptosis at the clinical relevant concentrations (up to 10 μM). Thorough comparisons of the molecular changes between Huh7 and resistant cells showed that the phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathway played a significant role in mediating acquired resistance to sorafenib in Huh7-R1 and Huh7-R2 cells. Phospho-Akt and p85 (a regulatory subunit of PI3K) were up-regulated, whereas tumor suppressor phosphatase and tensin homolog were down-regulated in these resistant cells. In addition, ectopic expression of constitutive Akt in Huh7 demonstrated similar resistance to sorafenib. The knockdown of Akt by RNA interference reversed resistance to sorafenib in Huh7-R1 cells, indicating the importance of Akt in drug sensitivity. Furthermore, the combination of 8-[4-(1-aminocyclobutyl)phenyl]-9-phenyl-1,2,4-triazolo[3,4-f][1,6]naphthyridin-3(2H)-one dihydrochloride (MK-2206), a novel allosteric Akt inhibitor, and sorafenib restored the sensitivity of resistant cells to sorafenib-induced apoptosis. In conclusion, activation of PI3K/Akt signaling pathway mediates acquired resistance to sorafenib in HCC, and the combination of sorafenib and MK-2206, an Akt inhibitor, overcomes the resistance at clinical achievable concentrations.
TL;DR: It is proposed that the development of sunitinib resistance is partly mediated by the survival of MDSCs intratumorally, thereby providing sustained immune suppression and angiogenesis.
TL;DR: Preclinical evidence that supports the use of dasatinib in combination for the treatment of solid tumors is reviewed and various clinical trials developed following a preclinical rationale are described.
Abstract: Dasatinib is a small molecule tyrosine kinase inhibitor that targets a wide variety of tyrosine kinases implicated in the pathophysiology of several neoplasias. Among the most sensitive dasatinib targets are ABL, the SRC family kinases (SRC, LCK, HCK, FYN, YES, FGR, BLK, LYN, and FRK), and the receptor tyrosine kinases c-KIT, platelet-derived growth factor receptor (PDGFR) α and β, discoidin domain receptor 1 (DDR1), c-FMS, and ephrin receptors. Dasatinib inhibits cell duplication, migration, and invasion, and it triggers apoptosis of tumoral cells. As a consequence, dasatinib reduces tumoral mass and decreases the metastatic dissemination of tumoral cells. Dasatinib also acts on the tumoral microenvironment, which is particularly important in the bone, where dasatinib inhibits osteoclastic activity and favors osteogenesis, exerting a bone-protecting effect. Several preclinical studies have shown that dasatinib potentiates the antitumoral action of various drugs used in the oncology clinic, paving the way for the initiation of clinical trials of dasatinib in combination with standard-of-care treatments for the therapy of various neoplasias. Trials using combinations of dasatinib with ErbB/HER receptor antagonists are being explored in breast, head and neck, and colorectal cancers. In hormone receptor–positive breast cancer, trials using combinations of dasatinib with antihormonal therapies are ongoing. Dasatinib combinations with chemotherapeutic agents are also under development in prostate cancer (dasatinib plus docetaxel), melanoma (dasatinib plus dacarbazine), and colorectal cancer (dasatinib plus oxaliplatin plus capecitabine). Here, we review the preclinical evidence that supports the use of dasatinib in combination for the treatment of solid tumors and describe various clinical trials developed following a preclinical rationale. Clin Cancer Res; 17(17); 5546–52. ©2011 AACR .
TL;DR: Activation of PI3 kinase pathway is associated with trastuzumab resistance, whereas low PTEN predicted for response to lapatinib, and these observations support clinical trials with the combination of both agents.
Abstract: Purpose Phosphatase and tensin homolog (PTEN) loss or activating mutations of phosphoinositol-3 (PI3) kinase (PIK3CA) may be associated with trastuzumab resistance. Trastuzumab, the humanized human epidermal growth factor receptor 2 (HER2) monoclonal antibody, and lapatinib, an epidermal growth factor receptor/HER2 tyrosine kinase inhibitor, are both established treatments for HER2-overexpressing breast cancers. Understanding of the cellular response to HER2-targeted therapies is needed to tailor treatments and to identify patients less likely to benefit. Methods We evaluated the effect of trastuzumab or lapatinib in three HER2-overexpressing cell lines. We confirmed the in vitro observations in two neoadjuvant clinical trials in patients with HER2 overexpression; 35 patients received trastuzumab as a single agent for the first 3 weeks, then docetaxel every 3 weeks for 12 weeks (trastuzumab regimen), whereas 49 patients received lapatinib as a single agent for 6 weeks, followed by trastuzumab/docetaxel fo...
TL;DR: Interestingly, long-term culture-initiating cell assays with MS-5/HOXB4 stromal feeders increased detected numbers of LSCs in 3 patients, and the relation between LSC persistency and a potential risk of disease relapse for patients with durable UMRD (on or off tyrosine kinase inhibitor therapy) warrants further investigation.
TL;DR: The most effective way of cancer treatment by using tyrosine kinase inhibitors is to consider each patient/tumor individually and to determine the strategy that specifically targets the consequences of altered (epi)genetics of the tumor.
Abstract: Since in most tumors multiple signaling pathways are involved, many of the inhibitors in clinical development are designed to affect a wide range of targeted kinases. The most important tyrosine kinase families in the development of tyrosine kinase inhibitors are the ABL, SCR, platelet derived growth factor, vascular endothelial growth factor receptor and epidermal growth factor receptor families. Both multi-kinase inhibitors and single-kinase inhibitors have advantages and disadvantages, which are related to potential resistance mechanisms, pharmacokinetics, selectivity and tumor environment. In different malignancies various tyrosine kinases are mutated or overexpressed and several resistance mechanisms exist. Pharmacokinetics is influenced by interindividual differences and differs for two single targeted inhibitors or between patients treated by the same tyrosine kinase inhibitor. Different tyrosine kinase inhibitors have various mechanisms to achieve selectivity, while differences in gene expression exist between tumor and stromal cells. Considering these aspects, one type of inhibitor can generally not be preferred above the other, but will depend on the specific genetic constitution of the patient and the tumor, allowing personalized therapy. The most effective way of cancer treatment by using tyrosine kinase inhibitors is to consider each patient/tumor individually and to determine the strategy that specifically targets the consequences of altered (epi)genetics of the tumor. This strategy might result in treatment by a single multi kinase inhibitor for one patient, but in treatment by a couple of single kinase inhibitors for other patients.
TL;DR: It is shown that the expression level of the transcription factor STAT5 is another parameter that determines the sensitivity of BCR-ABL1(+) cells against tyrosine kinase inhibitors (TKIs), and suggests that STAT5 may serve as an attractive target to overcome imatinib resistance in BCR(+) leukemia.
TL;DR: It is demonstrated that targeted inhibition of BCL6 leads to eradication of drug-resistant and leukaemia-initiating subclones and the discovery of a novel mechanism of drug resistance, which is based on protective feedback signalling ofLeukaemia cells in response to treatment with TKI.
Abstract: Tyrosine kinase inhibitors (TKIs) are widely used to treat patients with leukaemia driven by BCR-ABL1 (ref. 1) and other oncogenic tyrosine kinases. Recent efforts have focused on developing more potent TKIs that also inhibit mutant tyrosine kinases. However, even effective TKIs typically fail to eradicate leukaemia-initiating cells (LICs), which often cause recurrence of leukaemia after initially successful treatment. Here we report the discovery of a novel mechanism of drug resistance, which is based on protective feedback signalling of leukaemia cells in response to treatment with TKI. We identify BCL6 as a central component of this drug-resistance pathway and demonstrate that targeted inhibition of BCL6 leads to eradication of drug-resistant and leukaemia-initiating subclones.
TL;DR: After a phase I dose escalation study of sorafenib in patients with advanced myelodysplastic syndrome and relapsed or refractory acute leukemias, it is concluded that sorAFenib is active and well tolerated in acute myelogenous leukemia with fms-like tyrosine kinase 3 internal tandem duplication mutation.
Abstract: Background Sorafenib is a multi-kinase inhibitor with activity against fms-like tyrosine kinase 3 with internal tandem duplication mutation and Raf kinase among others A phase I dose escalation study of sorafenib was conducted in patients with advanced myelodysplastic syndrome and relapsed or refractory acute leukemias
Design and Methods Fifty patients received one of two different schedules; Schedule “A”: once or twice daily, five days per week, every week for a 21 day cycle, and Schedule “B”: once or twice daily, for 14 days every 21 days Dose limiting toxicities were grade 3/4 hypertension, hyperbilirubinemia, and amylase elevation The recommended phase II dose in hematologic malignancies is 400 mg twice daily for both schedules
Results Complete remissions or complete remissions with incomplete recovery of platelets were achieved in 5 (10%) patients (all with fms-like tyrosine kinase 3-internal tandem duplication) Significant reduction in bone marrow and/or peripheral blood blasts was seen in an additional 17 (34%) patients (all with fms-like tyrosine kinase 3-internal tandem duplication) Eleven of these responses (including 3 complete remissions/complete remissions with incomplete recovery) lasted for 2 cycles or beyond In conclusion, sorafenib is active and well tolerated in acute myelogenous leukemia with fms-like tyrosine kinase 3 internal tandem duplication mutation
Conclusions Additional studies of sorafenib in patients with acute myelogenous leukemia, particularly those with fms-like tyrosine kinase 3 internal tandem duplication, are warranted, including sorafenib-based combinations ( ClinicalTrialsgov Identifier: [NCT00217646][1] )
[1]: /lookup/external-ref?link_type=CLINTRIALGOV&access_num=NCT00217646&atom=%2Fhaematol%2F96%2F1%2F62atom
TL;DR: How models and mechanisms of trastuzumab-resistance enhance the understanding of the clinical resistance to HER2-directed therapies are discussed are discussed.
Abstract: The antibody trastuzumab and the tyrosine kinase inhibitor lapatinib are approved by the FDA for the treatment of HER2-overexpressing breast cancer. These anti-HER2 drugs are changing the natural history of HER2-overexpressing breast cancer. However, therapeutic resistance to trastuzumab or lapatinib, as either single-agents or in combination with chemotherapy in the metastatic setting, typically occurs within months of starting therapy. Several mechanisms of trastuzumab-resistance have been reported that include signaling from other HER receptors, signaling from receptor tyrosine kinases (RTKs) outside of the HER (ErbB) family, increased phosphatidylinositol-3-kinase signaling, and the presence of truncated forms of HER2. Mechanisms of resistance to lapatinib also point to increased phosphatidylinositol 3-kinase signaling as well as derepression/activation of compensatory survival pathways. In this review, we discuss how these models and mechanisms enhance our understanding of the clinical resistance to HER2-directed therapies.
TL;DR: Taken together, gefitinib reaches high concentrations in the tumor tissue and efficiently dephosphorylates its target, however, regulation of downstream signal transducers in the EGFR pathway seems to be dominated by regulatory circuits independent of EGFR phosphorylation.
Abstract: Amplification of the epidermal growth factor receptor (EGFR) gene is one of the most common oncogenic alterations in glioblastoma (45%) making it a prime target for therapy. However, small molecule inhibitors of the EGFR tyrosine kinase showed disappointing efficacy in clinical trials for glioblastoma. Here we aimed at investigating the molecular effects of the tyrosine kinase inhibitor gefitinib on the EGFR signaling pathway in human glioblastoma. Twenty-two patients selected for reoperation of recurrent glioblastoma were treated within a phase II trial for 5 days with 500 mg gefitinib before surgery followed by postoperative gefitinib until recurrence. Resected glioblastoma tissues exhibited high concentrations of gefitinib (median, 4.1 μg/g), 20 times higher than respective plasma. EGFR-pathway activity was evaluated with phosphorylation-specific assays. The EGFR was efficiently dephosphorylated in treated patients as compared to a control cohort of 12 patients. However, no significant effect on 12 pathway constituents was detected. In contrast, in vitro treatment of a glioblastoma cell line, BS-153, with endogenous EGFRwt amplification and EGFRvIII expression resulted not only in dephosphorylation of the EGFR, but also of key regulators in the pathway such as AKT. Treating established xenografts of the same cell line as an in vivo model showed dephosphorylation of the EGFR without affecting downstream signal transductors, similar to the human glioblastoma. Taken together, gefitinib reaches high concentrations in the tumor tissue and efficiently dephosphorylates its target. However, regulation of downstream signal transducers in the EGFR pathway seems to be dominated by regulatory circuits independent of EGFR phosphorylation.
TL;DR: It took an unprecedented four years from the discovery of ALK rearrangement in NSCLC to the approval of crizotinib, the first ever ALK inhibitor, for the treatment of AlK-rearranged NSCLc.
Abstract: Epidermal growth factor receptor (EGFR) tyrosine inhibitors were first approved for the treatment of non-small cell lung cancer (NSCLC) in 2003 in the US. Activating EGFR mutations were subsequently discovered in 2004, and heralded the era of molecular targeted therapy in NSCLC. The discovery of anaplastic lymphoma kinase (ALK) rearrangement in NSCLC in 2007 by two independent groups not only represents the first time ALK rearrangement has been discovered in common solid tumors but also represents another important milestone in the era of molecular targeted therapy in NSCLC. Crizotinib, a mesenchymal-epithelial transition (MET)/ALK multi-targeted receptor tyrosine kinase inhibitor went into early Phase I clinical development in 2007. Using the knowledge that NSCLC patients with activating EGFR mutations benefited from EGFR tyrosine kinase inhibitors, crizotinib was rapidly and successfully developed as an inhibitor in ALK-rearranged NSCLC, based on a break apart fluorescence in situ hybridization assay, developed by two of the crizotinib Phase I sites. It cumulated in the conditional approval of crizotinib by the US Food and Drug Administration on August 26, 2011 for the treatment of ALK-rearranged NSCLC. The conditional approval was based on response rates of 50% and 61% from 255 ALK-rearranged NSCLC patients enrolled in two single-arm trials. Common adverse events of crizotinib include mild transient visual disorders, mild gastrointestinal toxicities, fatigue, rare alanine transaminase elevations, and even rarer pneumonitis (1.6%). Confirmatory trials comparing crizotinib with standard chemotherapy are ongoing. It took an unprecedented four years from the discovery of ALK rearrangement in NSCLC to the approval of crizotinib, the first ever ALK inhibitor, for the treatment of ALK-rearranged NSCLC.
TL;DR: In mice, the ABL family tyrosine kinase inhibitor, imatinib (Gleevec), when administered prophylactically or therapeutically, reduced both the number of granulomatous lesions and bacterial load in infected organs and was also effective against a rifampicin-resistant strain.
TL;DR: Understanding the pathogenesis of tyrosine kinase inhibitor resistance and the molecular rationale for the development of second and now third generation therapies for patients with CML will be keys to further disease control over the next 10 years.
Abstract: Although only 5000 new cases of chronic myeloid leukemia (CML) were seen in the United States in 2009, this neoplasm continues to make scientific headlines year-after-year. Advances in understanding the molecular pathogenesis coupled with exciting developments in both drug design and development, targeting the initiating tyrosine kinase, have kept CML in the scientific limelight for more than a decade. Indeed, imatinib, a small-molecule inhibitor of the leukemia-initiating Bcr-Abl tyrosine kinase, has quickly become the therapeutic standard for newly diagnosed chronic phase-CML (CP-CML) patients. Yet, nearly one-third of patients will still have an inferior response to imatinib, either failing to respond to primary therapy or demonstrating progression after an initial response. Significant efforts geared toward understanding the molecular mechanisms of imatinib resistance have yielded valuable insights into the cellular biology of drug trafficking, enzyme structure and function, and the rational design of novel small molecule enzyme inhibitors. Indeed, new classes of kinase inhibitors have recently been investigated in imatinib-resistant CML. Understanding the pathogenesis of tyrosine kinase inhibitor resistance and the molecular rationale for the development of second and now third generation therapies for patients with CML will be keys to further disease control over the next 10 years.
TL;DR: It is concluded that therapeutic targeting of both InsR and IGF- IR should be more effective than targeting IGF-IR alone in abrogating resistance to endocrine therapy in breast cancer.
Abstract: Estrogen receptor α (ER)-positive breast cancers adapt to hormone deprivation and become resistant to antiestrogens. In this study, we sought to identify kinases essential for growth of ER(+) breast cancer cells resistant to long-term estrogen deprivation (LTED). A kinome-wide siRNA screen showed that the insulin receptor (InsR) is required for growth of MCF-7/LTED cells. Knockdown of InsR and/or insulin-like growth factor-I receptor (IGF-IR) inhibited growth of 3 of 4 LTED cell lines. Inhibition of InsR and IGF-IR with the dual tyrosine kinase inhibitor OSI-906 prevented the emergence of hormone-independent cells and tumors in vivo, inhibited parental and LTED cell growth and PI3K/AKT signaling, and suppressed growth of established MCF-7 xenografts in ovariectomized mice, whereas treatment with the neutralizing IGF-IR monoclonal antibody MAB391 was ineffective. Combined treatment with OSI-906 and the ER downregulator fulvestrant more effectively suppressed hormone-independent tumor growth than either drug alone. Finally, an insulin/IGF-I gene expression signature predicted recurrence-free survival in patients with ER(+) breast cancer treated with the antiestrogen tamoxifen. We conclude that therapeutic targeting of both InsR and IGF-IR should be more effective than targeting IGF-IR alone in abrogating resistance to endocrine therapy in breast cancer.
TL;DR: Investigation is required to explain the large interindividual variability in the pharmacokinetics of these drugs and to assess the clinical relevance of interaction potential and inhibitory effects on the metabolizing enzymes and transporters.
Abstract: The 4-anilinoquinazolines (gefitinib, erlotinib and lapatinib) are members of a class of potent and selective inhibitors of the human epidermal growth factor receptor (HER) family of tyrosine kinases that have been developed to treat patients with tumours with defined genetic alterations of the HER tyrosine kinase domain They are characterized by a moderate rate of absorption after oral administration with peak plasma concentrations at several hours post-dose Absolute bioavailability of gefitinib and erlotinib is about 60% Low bioavailability is assumed for lapatinib The drugs are extensively distributed in human tissues, including tumour tissues, have a large volume of distribution at least 3-fold exceeding the volume of body water and are extensively (about 95%) protein bound to α(1)-acid glycoprotein and albumin Existing human data for gefitinib and erlotinib indicate that these substances penetrate into the central nervous system and accumulate in brain tumours, possibly due to leaks in the blood-brain barrier Gefitinib, erlotinib and the absorbed fraction of lapatinib undergo extensive metabolism - mainly via hepatic and intestinal cytochrome P450 (CYP) 3A4 and also via CYP2D6 (gefitinib) and CYP1A2 (erlotinib) - and are primarily eliminated by biotransformation The excretion of unchanged gefitinib, erlotinib, lapatinib and their metabolites occurs predominantly in the faeces and only a minor fraction is excreted in the urine No relevant effects of age, sex, bodyweight or race on their pharmacokinetics have been reported to date Limited available data indicate that genetic polymorphisms in enzymes and transporters involved in the pharmacokinetics of gefitinib (CYP2D6) and erlotinib (CYP3A4, CYP3A5 and ABCG2 [breast cancer resistance protein]) alter the exposure to these drugs Modification of drug dose should be considered in patients with severe hepatic impairment receiving these tyrosine kinase inhibitors and in current smokers receiving erlotinib Existing recommendations for dose adjustment (ie a dose decrement or increment for gefitinib, erlotinib and lapatinib in the presence of CYP3A4 inhibitors or inducers, respectively; a dose increase for erlotinib in smoking patients) need to be validated in clinical studies Further investigations are required to explain the large interindividual variability in the pharmacokinetics of these drugs and to assess the clinical relevance of interaction potential and inhibitory effects on the metabolizing enzymes and transporters
TL;DR: This review will focus on small-molecule TKIs targeting MET, FGFR, and IGF-IR and discuss the merits and demerits of two types of agents, i.e., those with only one or a few targets and those directed at multiple targets.
Abstract: The majority of growth factor receptors are composed of extracellular, transmembrane, and cytoplasmic tyrosine kinase (TK) domains. Receptor tyrosine kinase (RTK) activation regulates many key processes including cell growth and survival. However, dysregulation of RTK has been found in a wide range of cancers, and it has been shown to correlate with the development and progression of numerous cancers. Therefore, RTK has become an attractive therapeutic target. One way to effectively block signaling from RTK is inhibition of its catalytic activity with small-molecule inhibitors. Low-molecular-weight TK inhibitors (TKIs), such as imatinib, targeting tumors with mutant c-Kit, and gefitinib, targeting non-small cell lung cancer with mutant epidermal growth factor receptor (EGFR), have received marketing approval in Japan. MET, fibroblast growth factor receptor (FGFR), and insulin-like growth factor-I receptor (IGF-IR) are frequently genetically altered in advanced cancers. TKIs of these receptors have not yet appeared on the market, but many anticancer drug candidates are currently undergoing clinical trials. Most of these TKIs were designed to compete with ATP at the ATP-binding site within the TK domain. This review will focus on small-molecule TKIs targeting MET, FGFR, and IGF-IR and discuss the merits and demerits of two types of agents, i.e., those with only one or a few targets and those directed at multiple targets. Targeting agents specifically inhibiting the target kinase were previously searched for based on the hypothesis that a narrow target window might reduce unexpected side effects, but agents with multiple targets have been recently developed to overcome tumors resistant against a single-targeting agent.
TL;DR: In clinical samples, Slug expression was significantly higher in cancer cells with resistance to EGFR TKIs than in treatment-naive cancer cells, suggesting Slug contributes to the resistance to gefitinib and may be a potential therapeutic target for treating resistance toEGFR TkIs.
Abstract: Rationale: Non–small cell lung cancers carrying epidermal growth factor receptor (EGFR) mutations respond well to EGFR tyrosine kinase inhibitors (TKIs), but patients ultimately develop drug resistance and relapse. Although epithelial-mesenchymal transition (EMT) can predict resistance to EGFR TKIs, the molecular mechanisms are still unknown. Objectives: To examine the role of EMT regulators in resistance to gefitinib.Methods: The expression level of EMT regulators in gefitinib-sensitive cells (PC9) and gefitinib-resistant cells (PC9/gef) was determined using quantitative real-time reverse transcription–polymerase chain reaction and Western blot analysis. Molecular manipulations (silencing or overexpression) were performed to investigate the effects of EMT regulators on gefitinib resistance in vitro, and a xenograft mouse model was used for in vivo confirmation. In addition, cancer cells from 44 patients with malignant pleural effusions of lung adenocarcinoma were collected for analysis of EMT regulator m...
TL;DR: Two studies uncover a novel role of Bcr-Abl activity in treatment of liver fibrosis through multiple mechanisms and indicate that Nilotinib represents a potentially effective antifibrotic agent.
TL;DR: The data suggest that increased Src kinase activity is a mechanism of lapatinib resistance and support the combination of HER2 antagonists with Src inhibitors early in the treatment of Her2+ breast cancers in order to prevent or overcome resistance to HER2 inhibitors.
Abstract: Despite the initial effectiveness of the tyrosine kinase inhibitor lapatinib against HER2 gene-amplified breast cancers, most patients eventually relapse after treatment, implying that tumors acquire mechanisms of drug resistance. To discover these mechanisms, we generated six lapatinib-resistant HER2-overexpressing human breast cancer cell lines. In cells that grew in the presence of lapatinib, HER2 autophosphorylation was undetectable, whereas active phosphoinositide-3 kinase (PI3K)-Akt and mitogen-activated protein kinase (MAPK) were maintained. To identify networks maintaining these signaling pathways, we profiled the tyrosine phosphoproteome of sensitive and resistant cells using an immunoaffinity-enriched mass spectrometry method. We found increased phosphorylation of Src family kinases (SFKs) and putative Src substrates in several resistant cell lines. Treatment of these resistant cells with Src kinase inhibitors partially blocked PI3K-Akt signaling and restored lapatinib sensitivity. Further, SFK mRNA expression was upregulated in primary HER2+ tumors treated with lapatinib. Finally, the combination of lapatinib and the Src inhibitor AZD0530 was more effective than lapatinib alone at inhibiting pAkt and growth of established HER2-positive BT-474 xenografts in athymic mice. These data suggest that increased Src kinase activity is a mechanism of lapatinib resistance and support the combination of HER2 antagonists with Src inhibitors early in the treatment of HER2+ breast cancers in order to prevent or overcome resistance to HER2 inhibitors.