Phase II study of tivantinib (ARQ 197) in patients with metastatic triple-negative breast cancer

Unlocking c-MET: A comprehensive journey into targeted therapies for breast cancer

Breast cancer is the most common malignancy among women, posing a formidable health challenge worldwide. In this complex landscape, the c-MET (cellular-mesenchymal epithelial transition factor) receptor tyrosine kinase (RTK), also recognized as the hepatocyte growth factor (HGF) receptor (HGFR), emerges as a prominent protagonist, displaying overexpression in nearly 50% of breast cancer cases. Activation of c-MET by its ligand, HGF, secreted by neighboring mesenchymal cells, contributes to a cascade of tumorigenic processes, including cell proliferation, metastasis, angiogenesis, and immunosuppression. While c-MET inhibitors such as crizotinib, capmatinib, tepotinib and cabozantinib have garnered FDA approval for non-small cell lung cancer (NSCLC), their potential within breast cancer therapy is still undetermined. This comprehensive review embarks on a journey through structural biology, multifaceted functions, and intricate signaling pathways orchestrated by c-MET across cancer types. Furthermore, we highlight the pivotal role of c-MET-targeted therapies in breast cancer, offering a clinical perspective on this promising avenue of intervention. In this pursuit, we strive to unravel the potential of c-MET as a beacon of hope in the fight against breast cancer, unveiling new horizons for therapeutic innovation.

Recent Advances with Precision Medicine Treatment for Breast Cancer including Triple-Negative Sub-Type

Breast cancer is a heterogeneous disease with different molecular subtypes. Breast cancer is the second leading cause of mortality in woman due to rapid metastasis and disease recurrence. Precision medicine remains an essential source to lower the off-target toxicities of chemotherapeutic agents and maximize the patient benefits. This is a crucial approach for a more effective treatment and prevention of disease. Precision-medicine methods are based on the selection of suitable biomarkers to envision the effectiveness of targeted therapy in a specific group of patients. Several druggable mutations have been identified in breast cancer patients. Current improvements in omics technologies have focused on more precise strategies for precision therapy. The development of next-generation sequencing technologies has raised hopes for precision-medicine treatment strategies in breast cancer (BC) and triple-negative breast cancer (TNBC). Targeted therapies utilizing immune checkpoint inhibitors (ICIs), epidermal growth factor receptor inhibitor (EGFRi), poly(ADP-ribose) polymerase inhibitor (PARPi), antibody-drug conjugates (ADCs), oncolytic viruses (OVs), glucose transporter-1 inhibitor (GLUT1i), and targeting signaling pathways are potential treatment approaches for BC and TNBC. This review emphasizes the recent progress made with the precision-medicine therapy of metastatic breast cancer and TNBC.

Scaffold Repurposing Reveals New Nanomolar Phosphodiesterase Type 5 (PDE5) Inhibitors Based on Pyridopyrazinone Scaffold: Investigation of In Vitro and In Silico Properties

Inhibition of PDE5 results in elevation of cGMP leading to vascular relaxation and reduction in the systemic blood pressure. Therefore, PDE5 inhibitors are used as antihypertensive and antianginal agents in addition to their major use as male erectile dysfunction treatments. Previously, we developed a novel series of 34 pyridopyrazinone derivatives as anticancer agents (series A–H). Herein, a multi-step in silico approach was preliminary conducted to evaluate the predicted PDE5 inhibitory activity, followed by an in vitro biological evaluation over the enzymatic level and a detailed SAR study. The designed 2D-QSAR model which was carried out to predict the IC₅₀ of the tested compounds revealed series B, D, E and G with nanomolar range of IC₅₀ values (6.00–81.56 nM). A further docking simulation model was performed to investigate the binding modes within the active site of PDE5. Interestingly, most of the tested compounds showed almost the same binding modes of that of reported PDE5 inhibitors. To validate the in silico results, an in vitro enzymatic assay over PDE5 enzyme was performed for a number of the promising candidates with different substitutions. Both series E and G exhibited a potent inhibitory activity (IC₅₀ = 18.13–41.41 nM). Compound 11b (series G, oxadiazole-based derivatives with terminal 4-NO₂ substituted phenyl ring and rigid linker) was the most potent analogue with IC₅₀ value of 18.13 nM. Structure–activity relationship (SAR) data attained for various substitutions were rationalized. Furthermore, a molecular dynamic simulation gave insights into the inhibitory activity of the most active compound (11b). Accordingly, this report presents a successful scaffold repurposing approach that reveals compound 11b as a highly potent nanomolar PDE5 inhibitor worthy of further investigation.

Clinical considerations of CDK4/6 inhibitors in triple-negative breast cancer

The formation of cyclinD-CDK4/6 complex plays vital roles in the cell cycle transition from G1 phase to S phase which is characterized by vigorous transcription and synthesis. Through cyclinD-CDK4/6-Rb axis, CDK4/6 inhibitors arrest the cell cycle in the G1 phase and block the proliferation of aggressive cells, exhibiting promising effects in containing the aggressiveness of breast cancers. To date, there are three CDK4/6 inhibitors approved by the U.S. Food and Drug Administration in treating advanced hormone receptor-positive breast cancer, including palbociclib, abemaciclib, and ribociclib. In fact, several preclinical experiments and clinical trials presented therapeutic effects of CDK4/6 inhibitor-based treatment in triple-negative breast cancer.

Investigational Drug Treatments for Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer (BC) and accounts for 10–20% of cases. Due to the lack of expression of several receptors, hormone therapy is largely ineffective for treatment purposes. Nevertheless, TNBC often responds very well to chemotherapy, which constitutes the most often recommended treatment. New beneficial targeted therapies are important to be investigated in order to achieve enhanced outcomes in patients with TNBC. This review will focus on recent therapeutic innovations for TNBC, focusing on various inhibitors such as phosphoinositide 3-kinase (PI3K) pathway inhibitors, poly-ADP-ribosyl polymerase (PARP) inhibitors, aurora kinase inhibitors, histone deacetylase inhibitors (HDACIs), and immune checkpoint inhibitors.

The Role of microRNA Let-7d in Female Malignancies and Diseases of the Female Reproductive Tract

microRNAs are small noncoding RNAs that regulate gene expression at the posttranscriptional level. Let-7d is a microRNA of the conserved let-7 family that is dysregulated in female malignancies including breast cancer, ovarian cancer, endometrial cancer, and cervical cancer. Moreover, a dysregulation is observed in endometriosis and pregnancy-associated diseases such as preeclampsia and fetal growth restriction. Let-7d expression is regulated by cytokines and steroids, involving transcriptional regulation by OCT4, MYC and p53, as well as posttranscriptional regulation via LIN28 and ADAR. By downregulating a wide range of relevant mRNA targets, let-7d affects cellular processes that drive disease progression such as cell proliferation, apoptosis (resistance), angiogenesis and immune cell function. In an oncological context, let-7d has a tumor-suppressive function, although some of its functions are context-dependent. Notably, its expression is associated with improved therapeutic responses to chemotherapy in breast and ovarian cancer. Studies in mouse models have furthermore revealed important roles in uterine development and function, with implications for obstetric diseases. Apart from a possible utility as a diagnostic blood-based biomarker, pharmacological modulation of let-7d emerges as a promising therapeutic concept in a variety of female disease conditions.

c-Met expression in renal cell carcinoma with bone metastases

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Bone is a common metastatic site in renal cell carcinoma (RCC).

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HGF/c-Met pathway is particularly relevant in tumors with bone metastases.

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c-Met/HGF pathway is involved in RCC progression, conferring poor prognosis.

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Several c-Met targeting therapies are currently in clinical development.

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c-Met expression is an important therapeutic target in RCC with bone metastases.

Hepatocyte growth factor (HGF)/c-Met pathway is implicated in embryogenesis and organ development and differentiation. Germline or somatic mutations, chromosomal rearrangements, gene amplification, and transcriptional upregulation in MET or alterations in autocrine or paracrine c-Met signalling have been associated with cancer cell proliferation and survival, including in renal cell carcinoma (RCC), and associated with disease progression. HGF/c-Met pathway has been shown to be particularly relevant in tumors with bone metastases (BMs). However, the efficacy of targeting c-Met in bone metastatic disease, including in RCC, has not been proven. Therefore, further investigation is required focusing the particular role of HGF/c-Met pathway in bone microenvironment (BME) and how to effectively target this pathway in the context of bone metastatic disease.

High hepatocyte growth factor expression in primary tumor predicts better overall survival in male breast cancer

BACKGROUND

Breast cancer is rare in men, but management is focused on tumor characteristics commonly found in female breast cancer. The tumor microenvironment of male breast cancer is less well understood, and insight may improve male breast cancer management. The hepatocyte growth factor (HGF)/c-MET axis and the stromal cell-derived factor-1 (CXCL12)/C-X-C chemokine receptor type 4 (CXCR4) axis are prognostic in women with breast cancer. We aimed to investigate these factors in male breast cancer and correlate them with patient survival.

METHODS

From 841 Dutch males with breast cancer who were enrolled in the EORTC 10085/TBCRC/BIG/NABCG International Male Breast Cancer Program (NCT01101425) and diagnosed between 1990 and 2010, archival primary tumor samples were collected. Tissue microarrays were constructed with 3 cores per sample and used for immunohistochemical analysis of HGF, c-MET, CXCL12, and CXCR4. Overall survival (OS) of the patients without metastases (M0) was analyzed using the Kaplan-Meier method. The value of the markers regarding OS was determined using univariable and multivariable Cox regression analyses, providing hazard ratios (HRs) and 95% confidence intervals (95% CIs).

RESULTS

Of 720 out of 841 patients, sufficient tissue was available for analysis; 487 out of 720 patients had M0 disease. Patients with high HGF expression and high CXCL12 expression had a superior OS (low vs high expression of both markers, 7.5 vs 13.0 years, hazard ratio [HR] 0.64, 95% CI 0.49-0.84, P = 0.001 [HGF]; 9.1 vs 15.3 years, HR 0.63, 95% CI 0.45-0.87, P = 0.005 [CXCL12]). Multivariate analysis identified HGF as an independent predictor for OS (HR 0.64, 95% CI 0.47-0.88, P = 0.001).

CONCLUSIONS

HGF and CXCL12 tumor expression appear to identify male breast cancer patients with a relatively good prognosis. Possibly, this could support male breast cancer-specific management strategies in the future.

Current treatment landscape for patients with locally recurrent inoperable or metastatic triple-negative breast cancer: a systematic literature review

Background

Metastatic triple-negative breast cancer (mTNBC), an aggressive histological subtype, has poor prognosis. Chemotherapy remains standard of care for mTNBC, although no agent has been specifically approved for this breast cancer subtype. Instead, chemotherapies approved for metastatic breast cancer (MBC) are used for mTNBC (National Comprehensive Cancer Network Guidelines [NCCN] v1.2019). Atezolizumab in combination with nab-paclitaxel was recently approved for programmed death-ligand 1 (PD-L1)–positive locally advanced or metastatic TNBC. Published historical data were reviewed to characterize the efficacy of NCCN-recommended (v1.2016) agents as first-line (1L) and second-line or later (2L+) treatment for patients with locally recurrent inoperable or metastatic TNBC (collectively termed mTNBC herein).

Methods

A systematic literature review was performed, examining clinical efficacy of therapies for mTNBC based on NCCN v1.2016 guideline recommendations. Data from 13 studies, either published retrospective mTNBC subgroup analyses based on phase III trials in MBC or phase II trials in mTNBC, were included.

Results

A meta-analysis of mTNBC subgroups from three phase III trials in 1L MBC reported pooled objective response rate (ORR) of 23%, median overall survival (OS) of 17.5 months, and median progression-free survival (PFS) of 5.4 months with single-agent chemotherapy. In two subgroup analyses from a phase III study and a phase II trial (n = 40 each), median duration of response (DOR) to 1L chemotherapy for mTNBC was 4.4–6.6 months; therefore, responses were not durable. A meta-analysis of seven cohorts showed the pooled ORR for 2L+ chemotherapy was 11% (95% CI, 9–14%). Median DOR to 2L+ chemotherapy in mTNBC was also limited (4.2–5.9 months) per two subgroup analyses from a phase III study. No combination chemotherapy regimens recommended by NCCN v1.2016 for treatment of MBC showed superior OS to single agents.

Conclusions

Chemotherapies have limited effectiveness and are associated with unfavorable toxicity profiles, highlighting a considerable unmet medical need for improved therapeutic options in mTNBC. In addition to the recently approved combination of atezolizumab and nab-paclitaxel for PD-L1–positive mTNBC, new treatments resulting in durable clinical responses, prolonged survival, and manageable safety profile would greatly benefit patients with mTNBC.

Tivantinib Hampers the Proliferation of Glioblastoma Cells via PI3K/Akt/Mammalian Target of Rapamycin (mTOR) Signaling

Background

Glioblastoma, the most common and malignant glial tumor, often has poor prognosis. Tivantinib has shown its potential in treating c-Met-high carcinoma. No studies have explored whether tivantinib inhibits the development of glioblastoma.

Material/Methods

The correlation between c-Met expression and clinicopathological characteristics of glioblastoma was investigated. U251 and T98MG glioblastoma cells treated with tivantinib, PI3K inhibitor (LY294002), PI3K activator (740 Y-P), and/or mammalian target of rapamycin (mTOR) inhibitor were subjected to MTT assay or colony formation assay to evaluate cell proliferation. The expression of mTOR signaling and caspase-3 in tivantinib-treated glioblastoma cells was differentially measured by western blotting.

Results

In a group of Chinese patients, expression of c-Met was elevated with the size of glioblastoma, but not with the other clinicopathological characteristics, including gender, age, grade, IDH status, 1p/19q status, and Ki67 status. High dose of tivantinib (1 μmol/L) obviously repressed the proliferation and colony formation of U251 and T98MG glioblastoma cells, but low dose (0.1 μmol/L) of tivantinib failed to retard cell proliferation. Tivantinib blocked PI3K/Akt/mTOR signaling but did not change the expression of cleaved caspase-3. PI3K activator 740 Y-P (20 μmol/L) significantly rescued tivantinib-induced decrease of cell proliferation. Tivantinib (1 μmol/L) in combination with PI3K inhibitor LY294002 (0.5 μmol/L) and mTOR inhibitor rapamycin (0.1 nmol/L) largely inhibited the proliferation of glioblastoma cells.

Conclusions

c-MET inhibitor tivantinib blocks PIKE/Akt/mTOR signaling and hampers the proliferation of glioblastoma cells, which endows the drug a therapeutic effect.

Pharmacogenetics of the systemic treatment in advanced hepatocellular carcinoma

Hepatocellular carcinoma (HCC) accounts for the majority of primary liver cancers. To date, most patients with HCC are diagnosed at an advanced tumor stage, excluding them from potentially curative therapies (i.e., resection, liver transplantation, percutaneous ablation). Treatments with palliative intent include chemoembolization and systemic therapy. Among systemic treatments, the small-molecule multikinase inhibitor sorafenib has been the only systemic treatment available for advanced HCC over 10 years. More recently, other small-molecule multikinase inhibitors (e.g., regorafenib, lenvatinib, cabozantinib) have been approved for HCC treatment. The promising immune checkpoint inhibitors (e.g., nivolumab, pembrolizumab) are still under investigation in Europe while in the US nivolumab has already been approved by FDA in sorafenib refractory or resistant patients. Other molecules, such as the selective CDK4/6inhibitors (e.g., palbociclib, ribociclib), are in earlier stages of clinical development, and the c-MET inhibitor tivantinib did not show positive results in a phase III study. However, even if the introduction of targeted agents has led to great advances in patient response and survival with an acceptable toxicity profile, a remarkable inter-individual heterogeneity in therapy outcome persists and constitutes a significant problem in disease management. Thus, the identification of biomarkers that predict which patients will benefit from a specific intervention could significantly affect decision-making and therapy planning. Germ-line variants have been suggested to play an important role in determining outcomes of HCC systemic therapy in terms of both toxicity and treatment efficacy. Particularly, a number of studies have focused on the role of genetic polymorphisms impacting the drug metabolic pathway and membrane translocation as well as the drug mechanism of action as predictive/prognostic markers of HCC treatment. The aim of this review is to summarize and critically discuss the pharmacogenetic literature evidences, with particular attention to sorafenib and regorafenib, which have been used longer than the others in HCC treatment.

Fendiline Enhances the Cytotoxic Effects of Therapeutic Agents on PDAC Cells by Inhibiting Tumor-Promoting Signaling Events: A Potential Strategy to Combat PDAC

The L-type calcium channel blocker fendiline has been shown to interfere with Ras-dependent signaling in K-Ras mutant cancer cells. Earlier studies from our lab had shown that treatment of pancreatic cancer cells with fendiline causes significant cytotoxicity and interferes with proliferation, survival, migration, invasion and anchorage independent growth. Currently there are no effective therapies to manage PDACs. As fendiline has been approved for treatment of patients with angina, we hypothesized that, if proven effective, combinatorial therapies using this agent would be easily translatable to clinic for testing in PDAC patients. Here we tested combinations of fendiline with gemcitabine, visudyne (a YAP1 inhibitor) or tivantinib (ARQ197, a c-Met inhibitor) for their effectiveness in overcoming growth and oncogenic characteristics of PDAC cells. The Hippo pathway component YAP1 has been shown to bypass K-Ras addiction, and allow tumor growth, in a Ras-null mouse model. Similarly, c-Met expression has been associated with poor prognosis and metastasis in PDAC patients. Our results presented here show that combinations of fendiline with these inhibitors show enhanced anti-tumor activity in Panc1, MiaPaCa2 and CD18/HPAF PDAC cells, as evident from the reduced viability, migration, anchorage-independent growth and self-renewal. Biochemical analysis shows that these agents interfere with various signaling cascades such as the activation of Akt and ERK, as well as the expression of c-Myc and CD44 that are altered in PDACs. These results imply that inclusion of fendiline may improve the efficacy of various chemotherapeutic agents that could potentially benefit PDAC patients.

Targeting the Hepatocyte Growth Factor and c-Met Signaling Axis in Bone Metastases

Bone metastasis is the terminal stage disease of prostate, breast, renal, and lung cancers, and currently no therapeutic approach effectively cures or prevents its progression to bone metastasis. One of the hurdles to the development of new drugs for bone metastasis is the complexity and heterogeneity of the cellular components in the metastatic bone microenvironment. For example, bone cells, including osteoblasts, osteoclasts, and osteocytes, and the bone marrow cells of diverse hematopoietic lineages interact with each other via numerous cytokines and receptors. c-Met tyrosine kinase receptor and its sole ligand hepatocyte growth factor (HGF) are enriched in the bone microenvironment, and their expression correlates with the progression of bone metastasis. However, no drugs or antibodies targeting the c-Met/HGF signaling axis are currently available in bone metastatic patients. This significant discrepancy should be overcome by further investigation of the roles and regulation of c-Met and HGF in the metastatic bone microenvironment. This review paper summarizes the key findings of c-Met and HGF in the development of novel therapeutic approaches for bone metastasis.

Targeted and immuno-biology driven treatment strategies for triple-negative breast cancer: current knowledge and future perspectives

Introduction: Accounting for about 15% of breast cancer patients, triple-negative breast cancer (TNBC) is responsible for 25% of disease related deaths, more frequent distant spread and visceral metastasis. However, improving survival in TNBC failed and primary resistance, immunological ignorance and tumor heterogeneity limit clinical activity of novel therapies. In view of recent molecular, genetic and immunologic insights, this review aims to describe the current status of immunological and targeted treatments from a hypothesis driven perspective. Areas covered: Recent preclinical studies and ongoing clinical trials for immune directed and targeted treatments of TNBC are summarized, including immune-checkpoint blockade, resistance mechanisms, inhibition of poly (ADP-ribose) polymerase (PARP), combinatorial strategies as well as preclinical, hypothesis generating studies. Expert commentary: Sustained responses have been observed with immune-checkpoint blockade and PARP inhibitors demonstrated remarkable efficacy in germline BRCA mutated TNBC. In order to generate clinical success of many other, to date ineffective, targeted and immune therapies, the integration of multidimensional, large amounts of data, will be essential and likely accelerate treatment progress of TNBC.

Boswellia frereana suppresses HGF-mediated breast cancer cell invasion and migration through inhibition of c-Met signalling

BACKGROUND

Hepatocyte growth factor (HGF) plays a pivotal role in breast cancer cell motility, invasion and angiogenesis. These pro-metastatic events are triggered through HGF coupling and activation of the c-Met receptor. Reports have demonstrated that HGF/c-Met signalling plays an important part in breast cancer progression and that their expression is linked to poor patient outcome. In the present study, we investigated the anti-metastatic potential of an extract from traditional Somalian frankincense, Boswellia frereana, on human breast cancer cells. In addition, we also examined the effect of this Boswellia frereana extract (BFE) upon HGF-mediated stimulation of the c-Met receptor.

METHODS

Two triple negative human breast cancer cell lines, BT549 and MDA-MB-231, were utilised in the study to examine the effect of BFE on tumour cell proliferation, migration, matrix-adhesion, angiogenesis and invasion. Cell migration was investigated using a Cell IQ time-lapsed motion analysis system; while tumour cell-matrix adhesion, angiogenesis and invasion were assessed through Matrigel-based in vitro assays. Breast cancer cell growth and spheroid formation was examined through proliferation assay and 3D non-scaffold cell culture techniques. Western Blotting was employed to determine the phosphorylation status of the c-Met receptor tyrosine kinase following BFE treatment and subsequent HGF stimulation.

RESULTS

Following HGF treatment, the breast cancer cells displayed a significant increase in migration, matrix adhesion, vessel/tubule formation, invasion and c-Met activation. HGF did not appear to have any bearing on the proliferation rate or spheroid formation of these breast cancer cells. The addition of the BFE extract quenched the HGF-enhanced migratory, angiogenic and invasive potential of these cells. Further study revealed that BFE inhibited c-Met receptor tyrosine kinase phosphorylation within these breast cancer cells.

CONCLUSIONS

Our findings reveal that BFE was able to significantly suppress the influence of HGF in breast cancer cell motility and invasion in vitro, through the ability of BFE to reduce HGF/c-Met signalling events. Therefore, these results indicate that BFE could play a novel role in the treatment of breast cancer.

Retrospective Assessment of a Serum Proteomic Test in a Phase III Study Comparing Erlotinib plus Placebo with Erlotinib plus Tivantinib (MARQUEE) in Previously Treated Patients with Advanced Non-Small Cell Lung Cancer

BACKGROUND

The VeriStrat test provides accurate predictions of outcomes in all lines of therapy for patients with non-small cell lung cancer (NSCLC). We investigated the predictive and prognostic role of VeriStrat in patients enrolled on the MARQUEE phase III trial of tivantinib plus erlotinib (T+E) versus placebo plus erlotinib (P+E) in previously treated patients with advanced NSCLC.

METHODS

Pretreatment plasma samples were available for 996 patients and were analyzed by matrix-assisted laser desorption/ionization-time of flight mass spectrometry to generate VeriStrat labels (good, VS-G, or poor, VS-P).

RESULTS

Overall, no significant benefit in overall survival (OS) and progression-free survival (PFS) were observed for the addition of tivantinib to erlotinib. Regardless of treatment arm, patients who were classified as VS-G had significantly longer PFS (3.8 mo for T+E arm, 2.0 mo for P+E arm) and OS (11.6 mo for T+E, 10.2 mo for P+E arm) than patients classified as VS-P (PFS: 1.9 mo for both arms, hazard ratio [HR], 0.584; 95% confidence interval [CI], 0.468-0.733; p < .0001 for T+E, HR, 0.686; 95% CI, 0.546-0.870; p = .0015 for P+E; OS: 4.0 mo for both arms, HR, 0.333; 95% CI, 0.264-0.422; p < .0001 for T+E; HR, 0.449; 95% CI, 0.353-0.576; p < .0001 for P+E). The VS-G population had higher OS than the VS-P population within Eastern Cooperative Oncology Group (ECOG) performance score (PS) categories. VS-G patients on the T+E arm had longer PFS, but not OS, than VS-G patients on the P+E arm (p = .0108). Among EGFR mutation-positive patients, those with VS-G status had a median OS more than twice that of any other group (OS: 31.6 mo for T+E and 22.8 mo for P+E), whereas VS-P patients had similar survival rates as VS-G, EGFR-wild type patients (OS: 13.7 mo for T+E and 6.5 mo for P+E).

CONCLUSION

In these analyses, VeriStrat showed a prognostic role within EGOC PS categories and regardless of treatment arm and EGFR status, suggesting that VeriStrat could be used to identify EGFR mutation-positive patients who will have a poor response to EGFR tyrosine kinase inhibitors.

IMPLICATIONS FOR PRACTICE

This study suggests that VeriStrat testing could enhance the prognostic role of performance status and smoking status and replicates findings from other trials that showed that the VeriStrat test identifies EGFR mutation-positive patients likely to have a poor response to EGFR tyrosine kinase inhibitors (TKIs). Although these findings should be confirmed in other populations, VeriStrat use could be considered in EGFR mutation-positive patients as an additional prognostic tool, and these results suggest that EGFR mutation-positive patients with VeriStrat "poor" classification could benefit from other therapeutic agents given in conjunction with TKI monotherapy.

A phase I trial of topotecan plus tivantinib in patients with advanced solid tumors

PURPOSE

Tyrosine kinase inhibitors (TKI) that target MET signaling have shown promise in various types of cancer, including lung cancer. Combination strategies have been proposed and developed to increase their therapeutic index. Based on preclinical synergy between inhibition of MET and topoisomerase I, a phase I study was designed to explore the combination of topotecan with the MET TKI tivantinib.

METHODS

Eligible patients with advanced solid malignancies for which there was no known effective treatment received topotecan at doses of 1.0-1.5 mg/m²/day for five consecutive days in 21-day cycles with continuous, oral tivantinib given at escalating doses of 120-360 mg orally twice daily. Pharmacokinetic analyses of tivantinib were included. Circulating tumor cells (CTC) were collected serially to identify peripheral changes in MET phosphorylation.

RESULTS

The trial included 18 patients, 17 of whom received treatment. At the planned doses, the combination of topotecan and tivantinib was not tolerable due to thrombocytopenia and neutropenia. The addition of G-CSF to attenuate neutropenia did not improve tolerability. Greater tivantinib exposure, assessed through pharmacokinetic analysis, was associated with greater toxicity. No responses were seen. MET phosphorylation was feasible in CTC, but no changes were seen with therapy.

CONCLUSIONS

The combination of topotecan and oral tivantinib was not tolerable in this patient population.

Precision medicine based on tumorigenic signaling pathways for triple-negative breast cancer

As a clinically heterogeneous subtype of breast cancer, triple-negative breast cancer (TNBC) is associated with a poor clinical outcome and a high relapse rate. Conventional chemotherapy and radiotherapy are effective treatments for patients with TNBC. However, the prognosis of TNBC remains unsatisfactory. Therefore, a large volume of research has explored the molecular markers and oncogenic signaling pathways associated with TNBC, including the cell cycle, DNA damage response and androgen receptor (AR) signaling pathways, to identify more efficient targeted therapies. However, whether these predicted pathways are effective targets has yet to be confirmed. In the present review, potentially carcinogenic signaling pathways in TNBCs from previous reports were considered, and ultimately five tumorigenic signaling pathways were selected, specifically receptor tyrosine kinases and downstream signaling pathways, the epithelial-to-mesenchymal transition and associated pathways, the immunoregulatory tumor microenvironment, DNA damage repair pathways, and AR and coordinating pathways. The conclusions of the preclinical and clinical trials of each pathway were then consolidated. Although a number of signaling pathways in TNBC have been considered in preclinical and clinical trials, the aforementioned pathways account for the majority of the malignant behaviors of TNBC. Identifying the alterations to different carcinogenic signaling pathways and their association with the heterogeneity of TNBC may facilitate the development of optimal precision medical approaches for patients with TNBC, potentially improving the efficiency of anticancer therapy.

Phase II randomized, double-blind, placebo-controlled study of tivantinib in men with asymptomatic or minimally symptomatic metastatic castration-resistant prostate cancer (mCRPC)

Background Tivantinib is a non-ATP competitive inhibitor of c-MET receptor tyrosine kinase that may have additional cytotoxic mechanisms including tubulin inhibition. Prostate cancer demonstrates higher c-MET expression as the disease progresses to more advanced stages and to a castration resistant state. Methods 80 patients (pts) with asymptomatic or minimally symptomatic mCRPC were assigned (2:1) to either tivantinib 360 mg PO BID or placebo (P). The primary endpoint was progression free survival (PFS). Results Of the 80 pts. enrolled, 78 (52 tivantinib, 26 P) received treatment and were evaluable. Median follow up is 8.9 months (range: 2.3 to 19.6 months). Patients treated with tivantinib had significantly better PFS vs. those treated with placebo (medians: 5.5 mo vs 3.7 mo, respectively; HR = 0.55, 95% CI: 0.33 to 0.90; p = 0.02). Grade 3 febrile neutropenia was seen in 1 patient on tivantinib while grade 3 and 4 neutropenia was recorded in 1 patient each on tivantinib and placebo. Grade 3 sinus bradycardia was recorded in two men on the tivantinib arm. Conclusions Tivantinib has mild toxicity and improved PFS in men with asymptomatic or minimally symptomatic mCRPC.

HER2 inhibition in gastro-oesophageal cancer: A review drawing on lessons learned from breast cancer

Human epidermal growth factor receptor 2 (HER2)-inhibition is an important therapeutic strategy in HER2-amplified gastro-oesophageal cancer (GOC). A significant proportion of GOC patients display HER2 amplification, yet HER2 inhibition in these patients has not displayed the success seen in HER2 amplified breast cancer. Much of the current evidence surrounding HER2 has been obtained from studies in breast cancer, and we are only recently beginning to improve our understanding of HER2-amplified GOC. Whilst there are numerous licensed HER2 inhibitors in breast cancer, trastuzumab remains the only licensed HER2 inhibitor for HER2-amplified GOC. Clinical trials investigating lapatinib, trastuzumab emtansine, pertuzumab and MM-111 in GOC have demonstrated disappointing results and have not yet changed the treatment paradigm. Trastuzumab deruxtecan may hold promise and is currently being investigated in phase II trials. HER2 amplified GOC differs from breast cancer due to inherent differences in the HER2 amino-truncation and mutation rate, loss of HER2 expression, alterations in HER2 signalling pathways and differences in insulin-like growth factor-1 receptor and MET expression. Epigenetic alterations involving different microRNA profiles in GOC as compared to breast cancer and intrinsic differences in the immune environment are likely to play a role. The key to effective treatment of HER2 amplified GOC lies in understanding these mechanisms and tailoring HER2 inhibition for GOC patients in order to improve clinical outcomes.

Untying the gordion knot of targeting MET in cancer

Despite compelling evidence backing the crucial role of a dysregulated MET axis in cancer and a myriad of agents targeting this pathway in active clinical development, the therapeutic value of MET inhibition in cancer oncology remains to be established. Although a series of disappointing clinical trials, at first, lessened fervor for targeting this pathway, investigations continue unabated with a number of novel active compounds entering clinical trials. Suboptimal designs which lacked biomarker selection have been the main reason for these early failures and this has stimulated a more biomarker enriched approach lately. Fresh insights into the mechanics of diverse MET aberrations (amplifications and mutations) have allowed trial enrichment for appropriate patients in appropriate disease settings. Development of MET inhibition as a therapeutic strategy in cancer has been a lesson in itself reflecting the challenging opportunities enclosed in the genetic landscape of cancer. Here, we will review the status of MET targeted therapy in development as it stands today, discuss emerging paradigms in MET inhibition and theorize on concepts for future development. We venture to propose that in spite of early disappointments, the future of this therapeutic strategy is promising with use of appropriate predictive biomarker in the right clinical context.

Tumor and circulating biomarkers in patients with second-line hepatocellular carcinoma from the randomized phase II study with tivantinib

ARQ 197-215 was a randomized placebo-controlled phase II study testing the MET inhibitor tivantinib in second-line hepatocellular carcinoma (HCC) patients. It identified tumor MET as a key biomarker in HCC.Aim of this research was to study the prognostic and predictive value of tumor (MET, the receptor tyrosine kinase encoded by the homonymous MNNG-HOS transforming gene) and circulating (MET, hepatocyte growth factor [HGF], alpha-fetoprotein [AFP], vascular endothelial growth factor [VEGF]) biomarkers in second-line HCC. Tumor MET-High status was centrally assessed by immunohistochemistry. Circulating biomarkers were centrally analyzed on serum samples collected at baseline and every 4-8 weeks, using medians as cut-off to determine High/Low status. Tumor MET, tested in 77 patients, was more frequently High after (82%) versus before (40%) sorafenib. A significant interaction (p = 0.04) between tivantinib and baseline tumor MET in terms of survival was observed. Baseline circulating MET and HGF (102 patients) High status correlated with shorter survival (HR 0.61, p = 0.03, and HR 0.60, p = 0.02, respectively), while the association between AFP (104 patients) or VEGF (103 patients) status and survival was non-significant.

CONCLUSIONS

Tumor MET levels were higher in patients treated with sorafenib. Circulating biomarkers such as MET and HGF may be prognostic in second-line HCC. These results need to be confirmed in larger randomized clinical trials.

EGFR-TKIs resistance via EGFR-independent signaling pathways

Tyrosine kinase inhibitors (TKIs)-treatments bring significant benefit for patients harboring epidermal growth factor receptor (EGFR) mutations, especially for those with lung cancer. Unfortunately, the majority of these patients ultimately develop to the acquired resistance after a period of treatment. Two central mechanisms are involved in the resistant process: EGFR secondary mutations and bypass signaling activations. In an EGFR-dependent manner, acquired mutations, such as T790 M, interferes the interaction between TKIs and the kinase domain of EGFR. While in an EGFR-independent manner, dysregulation of other receptor tyrosine kinases (RTKs) or abnormal activation of downstream compounds both have compensatory functions against the inhibition of EGFR through triggering phosphatidylinositol 3-kinase (PI3K)/Akt and mitogen-activated protein kinase (MAPK) signaling axes. Nowadays, many clinical trials aiming to overcome and prevent TKIs resistance in various cancers are ongoing or completed. EGFR-TKIs in accompany with the targeted agents for resistance-related factors afford a promising first-line strategy to further clinical application.

The efficacy and safety of tivantinib in the treatment of solid tumors: a systematic review and meta-analysis

BACKGROUND

Tivantinib was designed to kill cancers by targeting the mesenchymal-epithelial transition (MET) protein. Although numerous tivantinib clinical trials are ongoing, tivantinib's efficacy and safety are still not clear. This meta-analysis was done to evaluate tivantinib's efficacy and safety in solid tumor treatment.

MATERIALS AND METHODS

PUBMED, EMBASE, and other databases were searched for eligible tivantinib clinical trials. The hazard ratio (HR) and 95% confidence interval (CI) of progression-free and overall survival (PFS and OS, respectively) were pooled and analyzed to evaluate tivantinib's efficacy. Data concerning adverse events (Grade ≥ 3) were pooled to calculate relative risks (RRs) with 95% CI for tivantinib-treated compared with control arms.

FINDINGS

Patients (1824) from six randomized control trials (RCTs) were enrolled. Compared with controls, tivantinib produced a significant improvement in PFS (HR, 0.73; 95% CI 0.65-0.83) but not in OS. In the non-small-cell lung cancer (NSCLC) subgroup, tivantinib combined with erlotinib prolonged patients' PFS when compared with controls (HR, 0.75; 95% CI, 0.65-0.86). In the white population, tivantinib also significantly improve PFS between treatment and control arms (HR, 0.75; 95% CI, 0.65-0.87). Tivantinib significantly improved OS in patients with high levels of MET expression. Tivantinib was shown to increase the risk of anemia and neutropenia.

INTERPRETATION

Tivantinib was better in prolonging PFS (not OS) in patients with solid tumors. High MET expression cancers may benefit from tivantinib. Tivantinib appeared to be well-tolerated by patients.

Triple negative breast cancer: Emerging therapeutic modalities and novel combination therapies

Triple negative breast cancer (TNBC) is a complex and aggressive subtype of breast cancer which lacks oestrogen receptors, progesterone receptors and HER2 amplification, thereby making it difficult to target therapeutically. In addition, TNBC has the highest rates of metastatic disease and the poorest overall survival of all breast cancer subtypes. Resultantly, development of targeted therapies for TNBC is urgently needed. Recent efforts aimed at molecular characterisation of TNBCs have revealed various emerging therapeutic targets including PARP1, receptor and non-receptor tyrosine kinases, immune-checkpoints, androgen receptor and epigenetic proteins. Key successes include that of the PARP inhibitor, olaparib, which prolonged progression-free survival in a trial of BRCA-mutated breast cancer and for which clinical approval (in this setting) appears imminent. Nevertheless, the heterogeneity of TNBC has limited the clinical benefits of many trialled therapies in 'unselected' patients. Further, drug resistance develops following use of many targeted monotherapies due to upregulation of compensatory signalling pathways. In this review, we evaluate the current status of investigational targeted treatments and present evidence for the role of novel biomarkers and combination therapies in increasing response rates and circumventing drug-induced resistance. Additionally, we discuss promising novel targets in metastatic TNBC identified through preclinical and/or epidemiological studies.

A phase 1 study of the c-Met inhibitor, tivantinib (ARQ197) in children with relapsed or refractory solid tumors: A Children's Oncology Group study phase 1 and pilot consortium trial (ADVL1111)

BACKGROUND

The c-Met receptor tyrosine kinase is dysregulated in many pediatric cancers. Tivantinib is an oral small molecule that inhibits the c-Met receptor tyrosine kinase. A phase 1 and pharmacokinetic (PK) trial evaluating tivantinib was conducted in children with relapsed/refractory solid tumors.

METHODS

Oral tivantinib capsules were administered twice daily with food, continuously in 28-day cycles. Dose levels 170, 200, and 240 mg/m² /dose were evaluated using a rolling-six design (Part A). In Part B, subjects received tivantinib powder sprinkled on food at the recommended phase 2 dose (RP2D) from Part A. PK, CYP2C19 genotyping, and baseline tumor tissue c-Met expression were analyzed.

RESULTS

Thirty-six patients were enrolled: 20 in Part A, 6 in a PK expansion cohort, and 10 in Part B. Fifteen patients had primary central nervous system tumors and 21 had solid tumors. In Part A, there were no dose-limiting toxicities. One grade 4 intracranial hemorrhage occurred in a patient with a progressive brain tumor in the expanded PK cohort (240 mg/m² ). PK analysis showed marked interpatient variability (20-fold) in the C_max and AUC_0-8h across all dose levels. Sprinkling tivantinib powder over food did not alter exposure. Membranous and total c-Met expression was moderate (2), low (4), or not detected (26). Two patients had stable disease as the best response.

CONCLUSIONS

The RP2D of tivantinib given with food in children with refractory solid tumors is 240 mg/m² /dose. PK of tivantinib in children demonstrated high variability. Objective responses were not observed in this phase 1 trial.

Therapeutic Implications of the Molecular and Immune Landscape of Triple-Negative Breast Cancer

Treatment and management of breast cancer imposes a heavy burden on public health care, and incidence rates continue to increase. Breast cancer is the most common female neoplasia and primary cause of death among women worldwide. The recognition of breast cancer as a complex and heterogeneous disease, comprising different molecular entities, was a landmark in our understanding of this malignancy. Valuing the impact of the molecular characteristics on tumor behavior enabled a better assessment of a patient's prognosis and increased the predictive power to therapeutic response and clinical outcome. Molecular heterogeneity is also prominent in the triple-negative breast cancer subtype, and is reflected by the distinct prognostic and patient's sensitivity to treatment, being chemotherapy the only systemic treatment currently available. From a therapeutic perspective, gene expression profiling of triple-negative tumors has notably contributed to the exploration of new druggable targets and brought to light the need to align these patients to the various therapies according to their triple-negative subtype. Additionally, the higher amount of tumor infiltrating lymphocytes, and the prevalence of an increased expression of PD-1 receptor and its ligand, PD-L1, in triple-negative tumors, created a new treatment opportunity with immune checkpoint inhibitors. This manuscript addresses the current knowledge on the molecular and immune profiles of breast cancer, and its impact on the development of targeted therapies, with a particular emphasis on the triple-negative subtype.

Immunotherapy for triple-negative breast cancer: Existing challenges and exciting prospects

Patients with breast tumors that do not express the estrogen receptor, the progesterone receptor, nor Her-2/neu are hence termed "triple negatives", and generally have a poor prognosis, with high rates of systemic recurrence and refractoriness to conventional therapy regardless of the choice of adjuvant treatment. Thus, more effective therapeutic options are sorely needed for triple-negative breast cancer (TNBC), which occurs in approximately 20% of diagnosed breast cancers. In recent years, exploiting intrinsic mechanisms of the host immune system to eradicate cancer cells has achieved impressive success, and the advances in immunotherapy have yielded potential new therapeutic strategies for the treatment of this devastating subtype of breast cancer. It is anticipated that the responses initiated by immunotherapeutic interventions will explicitly target and annihilate tumor cells, while at the same time spare normal cells. Various immunotherapeutic approaches have been already developed and tested, which include the blockade of immune checkpoints using neutralizing or blocking antibodies, induction of cytotoxic T lymphocytes (CTLs), adoptive cell transfer-based therapy, and modulation of the tumor microenvironment to enhance the activity of CTLs. One of the most important areas of breast cancer research today is understanding the immune features and profiles of TNBC and devising novel immune-modulatory strategies to tackling TNBC, a subtype of breast cancer notorious for its poor prognosis and its imperviousness to conventional treatments. On the optimal side, one can anticipate that novel, effective, and personalized immunotherapy for TNBC will soon achieve more success and impact clinical treatment of this disease which afflicts approximately 20% of patients with breast cancer. In the present review, we highlight the current progress and encouraging developments in cancer immunotherapy, with a goal to discuss the challenges and to provide future perspectives on how to exploit a variety of new immunotherapeutic approaches including checkpoint inhibitors and neoadjuvant immunotherapy for the treatment of patients with TNBC.

A phase I study of tivantinib in combination with temsirolimus in patients with advanced solid tumors

Background A wide variety of human cancers exhibit dysregulated c-Met activity that has implications in oncogenesis. Phosphorylation of c-Met results in activation of the PI3K/AKT/mTOR pathway. Combined blockade of c-Met and mTOR pathways has shown efficacy in preclinical studies. Tivantinib is a c-Met inhibitor and temsirolimus is a selective mTOR inhibitor. We aimed to determine the maximum tolerated dose (MTD) and the recommended phase II dose (RP2D), dose-limiting toxicities (DLT), adverse events (AEs), clinical activity and pharmacokinetic (PK) parameters of the combination. Methods This open-label phase I study used a 3 + 3 dose escalation design. Patients (pts) were treated with escalating doses of tivantinib (120-360 mg tablets orally twice daily) and temsirolimus (20 mg IV weekly) followed by dose expansion at the MTD. Separate cohorts were planned for extensive (normal) and poor tivantinib metabolizers based on CYP2C19 genotypes. Cycles were 28 days besides cycle 1 that was 35 days to allow for PK analysis. Results Twenty-nine pts. [median age 58 (range 28-77)] were enrolled (21 in dose escalation and 8 in dose expansion). All were extensive CYP2C19 metabolizers. The most common types of cancer were colorectal, ovarian and non-small cell lung. Sixteen out of 21 and 6 out of 8 pts. were evaluable for DLT evaluation per protocol in the dose escalation and dose expansion phases, respectively. Pts remained on study for a median of 71 days (range 18-296). The MTD and RP2D was tivantinib 240 mg twice daily and temsirolimus 20 mg weekly. DLTs included grade (gr) 4 neutropenia (2 pts.; 1 with gr 3 febrile neutropenia), gr 3 abdominal pain (1 pt) and gr 2 mucositis resulting in inadequate drug delivery. The most common treatment related AEs grade ≥ 2 included: anemia (gr 2 in 9 pts., gr 3 in 3 pts), fatigue (gr 2 in 10 pts), anorexia (gr 2 in 9 pts), hypoalbuminemia (gr 2 in 6 pts., gr 3 in 2 pts), hypophosphatemia (gr 2 in 2 pts., gr 3 in 5 pts) and nausea (gr 2 in 6 pts., gr 3 in 1 pt). One pt. with ovarian cancer had a confirmed partial response and remained on study for 10 months, a second patient with ovarian cancer had stable disease and remained on study for 6 months and a third pt. with squamous cell carcinoma of the tongue had stable disease and remained on study for 7 months. Pharmacokinetic analysis showed that there is no interaction in the plasma concentrations between tivantinib and temsirolimus. Conclusions The combination of tivantinib with temsirolimus appears to be well tolerated with evidence of clinical activity.

Clinicopathological and prognostic significance of c-Met overexpression in breast cancer

BACKGROUND

c-Met has been shown to promote organ development and cancer progression in many cancers. However, clinicopathological and prognostic value of c-Met in breast cancer remains elusive.

METHODS

PubMed and EMBASE databases were searched for eligible studies. Correlation of c-Met overexpression with survival data and clinicopathological features was analyzed by using hazard ratio (HR) or odds ratio (OR) and fixed-effect or random-effect model according to heterogeneity. All statistical tests were two-sided.

RESULTS

32 studies with 8281 patients were analyzed in total. The c-Met overexpression was related to poor OS (overall survival) (HR=1.65 (1.328, 2.051)) of 18 studies with 4751 patients and poor RFS/DFS (relapse/disease free survival) (HR=1.53 (1.20, 1.95)) of 12 studies with 3598 patients. Subgroup analysis according to data source/methods/ethnicity showed c-Met overexpression was related to worse OS and RFS/DFS in Given by author group, all methods group and non-Asian group respectively. Besides, c-Met overexpression was associated with large tumor size, high histologic grade and metastasis.

CONCLUSIONS

Our results showed that c-Met overexpression was connected with poor survival rates and malignant activities of cancer, including proliferation, migration and invasion, which highlighted the potential of c-Met as significant candidate biomarker to identify patients with breast cancer at high risk of tumor death.

Molecular Biomarkers for Prediction of Targeted Therapy Response in Metastatic Breast Cancer: Trick or Treat?

In recent years, the study of genomic alterations and protein expression involved in the pathways of breast cancer carcinogenesis has provided an increasing number of targets for drugs development in the setting of metastatic breast cancer (i.e., trastuzumab, everolimus, palbociclib, etc.) significantly improving the prognosis of this disease. These drugs target specific molecular abnormalities that confer a survival advantage to cancer cells. On these bases, emerging evidence from clinical trials provided increasing proof that the genetic landscape of any tumor may dictate its sensitivity or resistance profile to specific agents and some studies have already showed that tumors treated with therapies matched with their molecular alterations obtain higher objective response rates and longer survival. Predictive molecular biomarkers may optimize the selection of effective therapies, thus reducing treatment costs and side effects. This review offers an overview of the main molecular pathways involved in breast carcinogenesis, the targeted therapies developed to inhibit these pathways, the principal mechanisms of resistance and, finally, the molecular biomarkers that, to date, are demonstrated in clinical trials to predict response/resistance to targeted treatments in metastatic breast cancer.

Design and synthesis of novel 7-aminosubstituted pyrido[2,3-b]pyrazines exhibiting anti-breast cancer activity

Breast cancer (BrCa) remains an unmet medical need despite the revolutionary development of antibody treatments and protein kinase inhibitors. In the current study, a series of novel substituted pyridopyrazine derivatives have been rationally designed and evaluated as multi-kinase inhibitors in the PI3K pathway. The target compounds were prepared from 6-amino-2-picoline, which upon nitration and selective reduction was converted to suitably substituted 6-methyl-7-aminopyrido[2,3-b]pyrazines. Suitable manipulation of the former amines provided the designed analogues, which were then assessed in vitro against several BrCa cell lines using the MTT cytotoxicity assay. The most potent compounds underwent evaluation in a broad spectrum of protein kinases, while their pharmacokinetic parameters were measured by LC-MS/MS. In vivo evaluation of a hit compound (14a) was performed in a HER2 amplified BrCa xenograft model (HCC1954) and efficacy was determined using Western blot based phosphokinase assays and immunohistochemistry. This derivative showed low micromolar cytotoxic potency in all BrCa cell lines, a mild inhibition of the PI3Kα wild type and H1047R mutated enzyme and excellent pharmacokinetic parameters following oral and intraperitoneal administration at the designed dose of 10 mg/kg, with absence of in vivo phenotypic toxicity. Interestingly, compound 14a inhibited the growth of xenografted tumors. Analysis of excised tumors from the treated animals showed a significantly reduced population of Ki-67 positive cells, as well as downregulated levels of phosphorylated AKT, ERK1/2 and SRC compared to vehicle treated animals. Finally, the specificity of 14a was assessed in a panel of 31 kinases where a mild, but direct, inhibition of the MET receptor tyrosine kinase was observed.

Profile of tivantinib and its potential in the treatment of hepatocellular carcinoma: the evidence to date

Hepatocellular carcinoma (HCC) is the fastest rising cause of cancer-related death in the United States and carries a very poor prognosis, with a median survival time of <50% at 1 year for advanced disease. To date, sorafenib is the only therapy approved by the Food and Drug Administration for the treatment of advanced HCC. Tivantinib (ARQ-197), a non-ATP competitive inhibitor of cellular mesenchymal–epithelial transcription factor (c-MET), has shown a survival benefit in patients with advanced HCC who have failed or are intolerant to sorafenib in Phase I and II trials. Those patients who have tumors with high concentrations of MET (MET-high) appear to derive the greatest benefit from tivantinib therapy. Currently, two large randomized double-blind placebo-controlled Phase III trials (METIV-HCC [NCT01755767] and JET-HCC [NCT02029157]) are evaluating tivantinib in patients with MET-high advanced HCC, with the primary end points of overall survival and progression-free survival, respectively. This study reviews the evidence for the use of tivantinib in advanced HCC. Specific topics addressed include the pharmacology, dosing, toxicity, and biomarkers associated with tivantinib use.

Cabozantinib for metastatic breast carcinoma: results of a phase II placebo-controlled randomized discontinuation study

Purpose

Cabozantinib (XL184), a multi-targeted oral tyrosine kinase inhibitor with activity against MET, VEGFR2, AXL, and other tyrosine kinases, was assessed in a cohort of metastatic breast cancer (MBC) patients in a phase II randomized discontinuation trial (RDT).

Methods

Patients received 100 mg cabozantinib daily during a 12-week lead-in stage. Those with stable disease per modified Response Evaluation Criteria in Solid Tumors version 1.0 at 12 weeks were randomized to either continue cabozantinib or receive placebo. Primary endpoints were objective response rate (ORR) during the 12-week lead-in stage and progression-free survival (PFS) after randomization. Patients were also followed for overall survival (OS).

Results

Forty-five patients with MBC and a median of three prior lines of chemotherapy for metastatic disease were enrolled. The ORR during the lead-in stage was 13.6 % (95 % confidence interval [CI] 6–25.7 %), and the disease control rate at week 12 was 46.7 % (95 % CI 31.7–61.6 %). Per the initial RDT study design, patients with stable disease at week 12 were randomized to cabozantinib or placebo. Following a Study Oversight Committee recommendation, randomization was suspended. Patients in the lead-in stage continued on open-label cabozantinib. Patients in the randomization stage were subsequently unblinded. The overall median PFS for all MBC patients was 4.3 months. Median OS was 11.4 months (95 % CI 10.5–16.5 months). The most common grade 3/4 adverse events in the lead-in stage were palmar-plantar erythrodysesthesia (13 %) and fatigue (11 %). One death from respiratory failure was reported as drug-related during the lead-in stage.

Conclusions

In heavily pretreated MBC patients, cabozantinib monotherapy demonstrated clinical activity including objective response and disease control.

Current advances in biomarkers for targeted therapy in triple-negative breast cancer

Triple-negative breast cancer (TNBC) is a complex heterogeneous disease characterized by the absence of three hallmark receptors: human epidermal growth factor receptor 2, estrogen receptor, and progesterone receptor. Compared to other breast cancer subtypes, TNBC is more aggressive, has a higher prevalence in African-Americans, and more frequently affects younger patients. Currently, TNBC lacks clinically accepted targets for tailored therapy, warranting the need for candidate biomarkers. BiomarkerBase, an online platform used to find biomarkers reported in clinical trials, was utilized to screen all potential biomarkers for TNBC and select only the ones registered in completed TNBC trials through clinicaltrials.gov. The selected candidate biomarkers were classified as surrogate, prognostic, predictive, or pharmacodynamic (PD) and organized by location in the blood, on the cell surface, in the cytoplasm, or in the nucleus. Blood biomarkers include vascular endothelial growth factor/vascular endothelial growth factor receptor and interleukin-8 (IL-8); cell surface biomarkers include EGFR, insulin-like growth factor binding protein, c-Kit, c-Met, and PD-L1; cytoplasm biomarkers include PIK3CA, pAKT/S6/p4E-BP1, PTEN, ALDH1, and the PIK3CA/AKT/mTOR-related metabolites; and nucleus biomarkers include BRCA1, the gluco-corticoid receptor, TP53, and Ki67. Candidate biomarkers were further organized into a "cellular protein network" that demonstrates potential connectivity. This review provides an inventory and reference point for promising biomarkers for breakthrough targeted therapies in TNBC.

Ockham's razor for the MET-driven invasive growth linking idiopathic pulmonary fibrosis and cancer

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) identifies a specific lung disorder characterized by chronic, progressive fibrosing interstitial pneumonia of unknown etiology, which lacks effective treatment. According to the current pathogenic perspective, the aberrant proliferative events in IPF resemble those occurring during malignant transformation.

MAIN BODY

Receptor tyrosine kinases (RTK) are known to be key players in cancer onset and progression. It has been demonstrated that RTK expression is sometimes also altered and even druggable in IPF. One example of an RTK-the MET proto-oncogene-is a key regulator of invasive growth. This physiological genetic program supports embryonic development and post-natal organ regeneration, as well as cooperating in the evolution of cancer metastasis when aberrantly activated. Growing evidence sustains that MET activation may collaborate in maintaining tissue plasticity and the regenerative potential that characterizes IPF.

CONCLUSION

The present work aims to elucidate-by applying the logic of simplicity-the bio-molecular mechanisms involved in MET activation in IPF. This clarification is crucial to accurately design MET blockade strategies within a fully personalized approach to IPF.

The Tyrosine Kinome Dictates Breast Cancer Heterogeneity and Therapeutic Responsiveness

Phospho-tyrosine signaling networks control numerous biological processes including cellular differentiation, cell growth and survival, motility, and invasion. Aberrant regulation of the tyrosine kinome is a hallmark of malignancy and influences all stages of breast cancer progression, from initiation to the development of metastatic disease. The success of specific tyrosine kinase inhibitors strongly validates the clinical relevance of tyrosine phosphorylation networks in breast cancer pathology. However, a significant degree of redundancy exists within the tyrosine kinome. Numerous receptor and cytoplasmic tyrosine kinases converge on a core set of signaling regulators, including adaptor proteins and tyrosine phosphatases, to amplify pro-tumorigenic signal transduction pathways. Mutational activation, amplification, or overexpression of one or more components of the tyrosine kinome represents key contributing events responsible for the tumor heterogeneity that is observed in breast cancers. It is this molecular heterogeneity that has become the most significant barrier to durable clinical responses due to the development of therapeutic resistance. This review focuses on recent literature that supports a prominent role for specific components of the tyrosine kinome in the emergence of unique breast cancer subtypes and in shaping breast cancer plasticity, sensitivity to targeted therapies, and the eventual emergence of acquired resistance. J. Cell. Biochem. 117: 1971-1990, 2016. © 2016 Wiley Periodicals, Inc.

Preclinical and clinical evaluation of MET functions in cancer cells and in the tumor stroma

A lot of attention has been dedicated to investigate the role of the tyrosine kinase receptor MET in tumors. The acquired notion that cancer cells from different histological origin strictly rely on the engagement of this specific oncogene for their growth and survival has certainly justified the development and the use of MET-targeted therapies in the clinic. However, the function and involvement of this pathway in the stroma (that often constitutes >50% of the global cellularity of the tumor) may offer the opportunity to conceive new patient stratification criteria, rational drug design and guided trials of new combination treatments. In this review, we will summarize and discuss the role of MET in cancer cells but especially in different stromal compartments, in light of the results showed by past and recent preclinical and clinical trials with anti-MET drugs.

cMET inhibitor crizotinib impairs angiogenesis and reduces tumor burden in the C3(1)-Tag model of basal-like breast cancer

Epidemiologic studies have associated obesity with increased risk of the aggressive basal-like breast cancer (BBC) subtype. Hepatocyte growth factor (HGF) signaling through its receptor, cMET, is elevated in obesity and is a pro-tumorigenic pathway strongly associated with BBC. We previously reported that high fat diet (HFD) elevated HGF, cMET, and phospho-cMET in normal mammary gland, with accelerated tumor development, compared to low fat diet (LFD)-fed lean controls in a murine model of BBC. We also showed that weight loss resulted in a significant reversal of HFD-induced effects on latency and elevation of HGF/cMET signaling in normal mammary and cMET in normal mammary and tumors. Here, we sought to inhibit BBC tumor progression in LFD- and HFD-fed C3(1)-Tag BBC mice using a small molecule cMET inhibitor, and began crizotinib treatment (50 mg/kg body weight by oral gavage) upon identification of the first palpable tumor. We next investigated if administering crizotinib in a window prior to tumor development would inhibit or delay BBC tumorigenesis. Treatment: Crizotinib significantly reduced mean tumor burden by 27.96 and 37.29 %, and mean tumor vascularity by 35.04 and 33.52 %, in our LFD- and HFD-fed C3(1)-Tag BBC mice, respectively. Prevention: Crizotinib significantly accelerated primary tumor progression in both diet groups but had no effect on total tumor progression or total tumor burden. In sum, cMET inhibition by crizotinib limited tumor development and microvascular density in basal-like tumor-bearing mice but did not appear to be an effective preventive agent for BBC.