Randomized, phase II, placebo-controlled trial of onartuzumab and/or bevacizumab in combination with weekly paclitaxel in patients with metastatic triple-negative breast cancer

Identifying therapeutic targets for breast cancer: insights from systematic Mendelian randomization analysis

Background

Breast cancer (BC) exhibits a high incidence rate, imposing a substantial burden on healthcare systems. Novel drug targets are urgently needed for BC. Mendelian randomization (MR) has gained widespread application for identifying fresh therapeutic targets. Our endeavor was to pinpoint circulatory proteins causally linked to BC risk and proffer potential treatment targets for BC.

Methods

Through amalgamating protein quantitative trait loci from 2,004 circulating proteins and comprehensive genome-wide association study data from the Breast Cancer Association Consortium, we conducted MR analyses. Employing Steiger filtering, bidirectional MR, Bayesian colocalization, phenotype scanning, and replication analyses, we further solidified MR study outcomes. Additionally, protein-protein interaction (PPI) network was harnessed to unveil latent associations between proteins and prevailing breast cancer medications. The phenome-wide MR (Phe-MR) was employed to assess potential side effects and indications for the druggable proteins of BC. Finally, we further affirmed the drugability of potential drug targets through mRNA expression analysis and molecular docking.

Results

Through comprehensive analysis, we identified five potential drug targets, comprising four (TLR1, A4GALT, SNUPN, and CTSF) for BC and one (TLR1) for BC_estrogen receptor positive. None of these five potential drug targets displayed reverse causation. Bayesian colocalization suggested that these five latent drug targets shared variability with breast cancer. All drug targets were replicated within the deCODE cohort. TLR1 exhibited PPI with current breast cancer therapeutic targets. Furthermore, Phe-MR unveiled certain adverse effects solely for TLR1 and SNUPN.

Conclusion

Our study uncovers five prospective drug targets for BC and its subtypes, warranting further clinical exploration.

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.

A drug design strategy based on molecular docking and molecular dynamics simulations applied to development of inhibitor against triple-negative breast cancer by Scutellarein derivatives

Triple-negative breast cancer (TNBC), accounting for 10-15% of all breast malignancies, is more prevalent in women under 40, particularly in those of African descent or carrying the BRCA1 mutation. TNBC is characterized by the absence of estrogen and progesterone receptors (ER, PR) and low or elevated HER2 expression. It represents a particularly aggressive form of breast cancer with limited therapeutic options and a poorer prognosis. In our study, we utilized the protein of TNBC collected from the Protein Data Bank (PDB) with the most stable configuration. We selected Scutellarein, a bioactive molecule renowned for its anti-cancer properties, and used its derivatives to design potential anti-cancer drugs employing computational tools. We applied and modified structural activity relationship methods to these derivatives and evaluated the probability of active (Pa) and inactive (Pi) outcomes using pass prediction scores. Furthermore, we employed in-silico approaches such as the assessment of absorption, distribution, metabolism, excretion, and toxicity (ADMET) parameters, and quantum calculations through density functional theory (DFT). Within the DFT calculations, we analyzed Frontier Molecular Orbitals, specifically the Highest Occupied Molecular Orbital (HOMO) and Lowest Unoccupied Molecular Orbital (LUMO). We then conducted molecular docking and dynamics against TNBC to ascertain binding affinity and stability. Our findings indicated that Scutellarein derivatives, specifically DM03 with a binding energy of -10.7 kcal/mol and DM04 with -11.0 kcal/mol, exhibited the maximum binding tendency against Human CK2 alpha kinase (PDB ID 7L1X). Molecular dynamic simulations were performed for 100 ns, and stability was assessed using root-mean-square deviation (RMSD) and root-mean-square fluctuation (RMSF) parameters, suggesting significant stability for our chosen compounds. Furthermore, these molecules met the pharmacokinetics requirements for potential therapeutic candidates, displaying non-carcinogenicity, minimal aquatic and non-aquatic toxicity, and greater aqueous solubility. Collectively, our computational data suggest that Scutellarein derivatives may serve as potential therapeutic agents for TNBC. However, further experimental investigations are needed to validate these findings.

Transdermal delivery of brucine-encapsulated liposomes significantly enhances anti-tumor outcomes in treating triple-negative breast cancer

Triple-negative breast cancer (TNBC) is always the most challenging breast cancer subtype. Herein, brucine, encapsulated in peptide-modified liposomes, was proposed for treating TNBC by transdermal delivery. For the TD peptide-modified brucine-loaded liposome (Bru-TD-Lip) we developed, it presents high encapsulation efficiency of brucine and stability. In vitro, Bru-TD-Lip shows the enhanced percutaneous permeability of brucine, is able to readily enter TNBC cells, and significantly inhibits the proliferation, migration, and invasion of these cells. In vivo, through transdermal delivery, Bru-TD-Lip presents good biosafety and anti-tumor efficacy. The transdermal delivery of Bru-TD-Lip effectively targets and inhibits subcutaneous mammary carcinogenesis in female nude mice. Compared with oral administration, the transdermal delivery significantly reduces the damage of brucine to major organs and enhances the antitumor outcomes of brucine in treating TNBC. This study provides a new therapeutic strategy for treating triple-negative breast cancer by brucine.

An Observatory for the MET Oncogene: A Guide for Targeted Therapies

The MET proto-oncogene encodes a pivotal tyrosine kinase receptor, binding the hepatocyte growth factor (HGF, also known as scatter factor, SF) and governing essential biological processes such as organogenesis, tissue repair, and angiogenesis. The pleiotropic physiological functions of MET explain its diverse role in cancer progression in a broad range of tumors; genetic/epigenetic alterations of MET drive tumor cell dissemination, metastasis, and acquired resistance to conventional and targeted therapies. Therefore, targeting MET emerged as a promising strategy, and many efforts were devoted to identifying the optimal way of hampering MET signaling. Despite encouraging results, however, the complexity of MET's functions in oncogenesis yields intriguing observations, fostering a humbler stance on our comprehension. This review explores recent discoveries concerning MET alterations in cancer, elucidating their biological repercussions, discussing therapeutic avenues, and outlining future directions. By contextualizing the research question and articulating the study's purpose, this work navigates MET biology's intricacies in cancer, offering a comprehensive perspective.

Development of a MET-targeted single-chain antibody fragment as an anti-oncogene targeted therapy for breast cancer

The usage of monoclonal antibodies (mAbs) and antibody fragments, as a matter associated with the biopharmaceutical industry, is increasingly growing. Harmonious with this concept, we designed an exclusive modeled single-chain variable fragment (scFv) against mesenchymal-epithelial transition (MET) oncoprotein. This scFv was newly developed from Onartuzumab sequence by gene cloning, and expression using bacterial host. Herein, we examined its preclinical efficacy for the reduction of tumor growth, invasiveness and angiogenesis in vitro and in vivo. Expressed anti-MET scFv demonstrated high binding capacity (48.8%) toward MET-overexpressing cancer cells. The IC₅₀ value of anti-MET scFv against MET-positive human breast cancer cell line (MDA-MB-435) was 8.4 µg/ml whereas this value was measured as 47.8 µg/ml in MET-negative cell line BT-483. Similar concentrations could also effectively induce apoptosis in MDA-MB-435 cancer cells. Moreover, this antibody fragment could reduce migration and invasion in MDA-MB-435 cells. Grafted breast tumors in Balb/c mice showed significant tumor growth suppression as well as reduction of blood-supply in response to recombinant anti-MET treatment. Histopathology and immunohistochemical assessments revealed higher rate of response to therapy. In our study, we designed and synthetized a novel anti-MET scFv which could effectively suppress MET-overexpressing breast cancer tumors.

The Potential of PSMA as a Vascular Target in TNBC

Recent studies proving prostate-specific membrane antigen (PSMA) expression on triple-negative breast cancer (TNBC) cells and adjacent endothelial cells suggest PSMA as a promising target for therapy of until now not-targetable cancer entities. In this study, PSMA and its isoform expression were analyzed in different TNBC cells, breast cancer stem cells (BCSCs), and tumor-associated endothelial cells. PSMA expression was detected in 91% of the investigated TNBC cell lines. The PSMA splice isoforms were predominantly found in the BCSCs. Tumor-conditioned media from two TNBC cell lines, BT-20 (high full-length PSMA expression, PSMAΔ18 expression) and Hs578T (low full-length PSMA expression, no isoform expression), showed significant pro-angiogenic effect with induction of tube formation in endothelial cells. All TNBC cell lines induced PSMA expression in human umbilical vein endothelial cells (HUVEC). Significant uptake of radiolabeled ligand [⁶⁸Ga]Ga-PSMA was detected in BCSC1 (4.2%), corresponding to the high PSMA expression. Moreover, hypoxic conditions increased the uptake of radiolabeled ligand [¹⁷⁷Lu]Lu-PSMA in MDA-MB-231 (0.4% vs. 3.4%, under hypoxia and normoxia, respectively) and MCF-10A (0.3% vs. 3.0%, under normoxia and hypoxia, respectively) significantly (p < 0.001). [¹⁷⁷Lu]Lu-PSMA-induced apoptosis rates were highest in BT-20 and MDA-MB-231 associated endothelial cells. Together, these findings demonstrate the potential of PSMA-targeted therapy in TNBC.

Impact of surgical management of primary tumors in stage IV breast cancer patients: a retrospective observational study based on SEER database

OBJECTIVES

Although primary tumour surgery could prolong survival for patients with stage IV breast cancer, how to select candidates for primary tumour surgery is still a challenging problem for medical oncologists.

DESIGN

This study is a retrospective database study.

SETTING AND PARTICIPANTS

In this study, we aimed at evaluating the primary site surgery effect and select the beneficial subgroups. 13 618 patients with stage IV breast cancer, diagnosed between 2010 and 2015, were collected from SEER*Stat database.

INTERVENTIONS

Based on the local surgery at primary tumour site, patients were categorised into three groups: primary tumour surgery performed group, recommended for primary tumour surgery but refused (RBR) group and surgery not recommended (NR) group.

PRIMARY AND SECONDARY OUTCOME MEASURES

All-cause survival and breast cancer-specific survival (BCSS).

RESULTS

Univariate Cox regression analyses showed that, compared with surgery group, patients in non-surgery (RBR and NR) groups tend to be older, T4, N0/NX, triple-negative and visceral metastatic. For both all-cause survival and BCSS, non-surgery, advanced T stage, triple-negative BC (TNBC) and visceral metastases were significant risk factors. Primary tumour surgery showed benefits for both all-cause survival (HR=0.44, 95% CI=0.39-0.49, p<0.0001) and BCSS (HR=0.43, 95% CI=0.38-0.49, p<0.0001). However, after propensity score matching, primary tumour surgery failed to demonstrate significant benefits for TNBC (HR=0.96, 95% CI=0.60-1.53, p=0.851) and patients with visceral metastases (HR=0.90, 95% CI=0.60-1.36, p=0.62).

CONCLUSION

Surgery was associated with prolonged survival in stage IV breast cancers, but not in patients with TNBC and visceral metastases.

Metastatic Triple Negative Breast Cancer: The New Era of Thinking

The heterogeneity of triple negative breast cancer (TNBC) is reflected in a bizarre response to therapy. Although it is chemotherapy sensitive, the failure is the usual pathway either in local or distance status. With progression in Gene Expression Profile (GEP) and other molecular techniques, TNBC is divided into sub-types with unique pathways. In the current review, we are trying to highlight based on the molecular classification of TNBC and the management based on every type.

Development of [89Zr]ZrDFO-amivantamab bispecific to EGFR and c-MET for PET imaging of triple-negative breast cancer

BACKGROUND

Amivantamab is a novel bispecific antibody that simultaneously targets the epidermal growth factor receptor (EGFR) and the hepatocyte growth factor receptor (HGFR/c-MET) that are overexpressed in several types of cancer including triple-negative breast cancer (TNBC). Targeting both receptors simultaneously can overcome resistance to mono-targeted therapy. The purpose of this study is to develop 89Zr-labeled amivantamab as a potential companion diagnostic imaging agent to amivantamab therapy using various preclinical models of TNBC for evaluation.

METHODS

Amivantamab was conjugated to desferrioxamine (DFO) and radiolabeled with 89Zr to obtain [89Zr]ZrDFO-amivantamab. Binding of the bispecific [89Zr]ZrDFO-amivantamab as well as its mono-specific "single-arm" antibody controls were determined in vitro and in vivo. Biodistribution studies of [89Zr]ZrDFO-amivantamab were performed in MDA-MB-468 xenografts to determine the optimal imaging time point. PET/CT imaging with [89Zr]ZrDFO-amivantamab or its isotype control was performed in a panel of TNBC xenografts with varying levels of EGFR and c-MET expression.

RESULTS

[89Zr]ZrDFO-amivantamab was synthesized with a specific activity of 148 MBq/mg and radiochemical yield of ≥ 95%. Radioligand binding studies and western blot confirmed the order of EGFR and c-MET expression levels: HCC827 lung cancer cell (positive control) > MDA-MB-468 > MDA-MB-231 > MDA-MB-453. [89Zr]ZrDFO-amivantamab demonstrated bispecific binding in cell lines co-expressed with EGFR and c-MET. PET/CT imaging with [89Zr]ZrDFO-amivantamab in TNBC xenografted mice showed standard uptake value (SUVmean) of 6.0 ± 1.1 in MDA-MB-468, 4.2 ± 1.4 in MDA-MB-231, and 1.5 ± 1.4 in MDA-MB-453 tumors, which are consistent with their receptors' expression levels on the cell surface.

CONCLUSION

We have successfully prepared a radiolabeled bispecific antibody, [89Zr]ZrDFO-amivantamab, and evaluated its pharmacologic and imaging properties in comparison with its single-arm antibodies and non-specific isotype controls. [89Zr]ZrDFO-amivantamab demonstrated the greatest uptake in tumors co-expressing EGFR and c-MET.

Combination of HGF/MET-targeting agents and other therapeutic strategies in cancer

MET receptor has emerged as a druggable target across several human cancers. Agents targeting MET and its ligand hepatocyte growth factor (HGF) including small molecules such as crizotinib, tivantinib and cabozantinib or antibodies including rilotumumab and onartuzumab have proven their values in different tumors. Recently, capmatinib was approved for treatment of metastatic lung cancer with MET exon 14 skipping. In this review, we critically examine the current evidence on how HGF/MET combination therapies may take advantage of synergistic effects, overcome primary or acquired drug resistance, target tumor microenvironment, modulate drug metabolism or tackle pharmacokinetic issues. Preclinical and clinical studies on the combination of HGF/MET-targeted agents with conventional chemotherapeutics or molecularly targeted treatments (including EGFR, VEGFR, HER2, RAF/MEK, and PI3K/Akt targeting agents) and also the value of biomarkers are examined. Our deeper understanding of molecular mechanisms underlying successful pharmacological combinations is crucial to find the best personalized treatment regimens for cancer patients.

MET-dependent solid tumours - molecular diagnosis and targeted therapy

Attempts to develop MET-targeted therapies have historically focused on MET-expressing cancers, with limited success. Thus, MET expression in the absence of a genomic marker of MET dependence is a poor predictor of benefit from MET-targeted therapy. However, owing to the development of more sensitive methods of detecting genomic alterations, high-level MET amplification and activating MET mutations or fusions are all now known to be drivers of oncogenesis. MET mutations include those affecting the kinase or extracellular domains and those that result in exon 14 skipping. The activity of MET tyrosine kinase inhibitors varies by MET alteration category. The likelihood of benefit from MET-targeted therapies increases with increasing levels of MET amplification, although no consensus exists on the optimal diagnostic cut-off point for MET copy number gains identified using fluorescence in situ hybridization and, in particular, next-generation sequencing. Several agents targeting exon 14 skipping alterations are currently in clinical development, with promising data available from early-phase trials. By contrast, the therapeutic implications of MET fusions remain underexplored. Here we summarize and evaluate the utility of various diagnostic techniques and the roles of different classes of MET-targeted therapies in cancers with MET amplification, mutation and fusion, and MET overexpression.

Meta-analyses on progression-free survival as a surrogate endpoint for overall survival in triple-negative breast cancer

PURPOSE

Earlier studies suggest progression-free survival (PFS) may be used as a surrogate endpoint for overall survival (OS) in metastatic breast cancer, which could shorten follow-up duration and speed up assessment of treatment effects. However, to our knowledge, the association between them is still unclear in advanced or metastatic triple-negative breast cancer (TNBC).

METHODS

A literature-based meta-analysis followed by correlation analysis was conducted in advanced or metastatic TNBC. Weighted multiple regression analysis was then used to test the strength of the association between medians of PFS and OS, and the association between HR_PFS and HR_OS.

RESULTS

Fourteen randomized clinical trials published between January 2007 and August 2019, 31 median pairs for PFS and OS, and 17 pairs for HR_PFS and HR_OS from 3,880 patients were selected. The Pearson correlation coefficient between medians of PFS and OS was 0.84 (95% confidence interval (CI) 0.68-0.92, p < 0.001), and the correlation coefficient between HR_PFS and HR_OS was 0.86 (95% CI 0.63-0.95, p < 0.001). Weighted multiple regression analysis showed HR_PFS was the most significant predictor of HR_OS among covariates analyzed (p < 0.001). Both the medians of PFS and OS correlation, and the HR_PFS and HR_OS correlation were 0.79 (p < 0.001), 0.80 (p = 0.001), respectively, in the 11 trials excluding immunotherapy and bevacizumab-based therapy trials.

CONCLUSIONS

Our analysis suggests PFS can be strongly correlated with OS and considered a valid surrogate endpoint for OS in advanced or metastatic TNBC.

The efficacy and safety of onartuzumab in patients with solid cancers: A meta-analysis of randomized trials

Background

Onartuzumab, a humanized monovalent monoclonal antibody to the MET protein, has been tested in various cancers. We conducted a meta-analysis of randomized phase II and III clinical trials to investigate the efficacy and safety of onartuzumab in solid cancers.

Methods

We searched PubMed, PMC, EMBASE, and the Cochrane library databases. We included randomized phase II or III trials that evaluated the additional benefits of onartuzumab in comparison with the standard treatments. Data on progression-free survival (PFS), overall survival (OS), and adverse events (AEs) were pooled and analyzed.

Results

From nine studies, a total of 2,138 patients were included in the meta-analysis. The addition of onartuzumab to the standard treatment resulted in no improvement of PFS (hazard ratio (HR) = 1.00 [95% confidence interval (CI), 0.90-1.11], P = 0.93) and OS (HR = 1.08 [95% CI, 0.94-1.23], P = 0.29). In the subgroup analysis with patients with non-small-cell lung cancer (NSCLC), onartuzumab was not associated with a significant improvement of OS (HR = 1.12 [95% CI, 0.93-1.34], P = 0.23) and PFS (HR = 1.05 [95% CI, 0.91-1.21], P = 0.52). With respect to AEs, onartuzumab increased the incidence of hypoalbuminemia (odds ratio (OR) = 14.8 [95% CI, 3.49-62.71], P < 0.001), peripheral edema (OR = 6.52 [95% CI, 3.60-11.81], P < 0.001), neutropenia (OR = 1.36 [95% CI, 1.03-1.79], P = 0.03), thrombocytopenia (OR = 1.98 [95% CI, 1.03-3.81], P = 0.04), and venous thrombotic events (OR = 3.05 [95% CI, 1.39-6.71], P = 0.006).

Conclusion

This meta-analysis indicates that the addition of onartuzumab to the standard treatments had no definite survival benefit with increased severe toxicities in patients with solid cancer.

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.

MET inhibitors in cancer: pitfalls and challenges

Introduction: The HGF/MET axis is a key therapeutic pathway in cancer; it is aberrantly activated because of mutations, fusions, amplification or aberrant ligand production. Extensive efforts have been made to discover predictive factors of anti-MET therapeutic efficacy, but they have mostly unsuccessful. An understanding of the intrinsic and acquired mechanism of MET resistance will be fundamental for the development of new therapeutic interventions.Areas covered: This article provides a systematic review of phase II randomized and phase III clinical trials investigating the use of MET inhibitors in the treatment of cancer. We discuss preliminary findings on efficacy and methodologic design flaws in these trials.Expert opinion: MET inhibitors showed poor activity in unselected patients or patients selected by MET expression, p-MET or high HGF basal levels. The efficacy in advanced solid tumors is very modest and in phase III clinical trials, survival differences did not fulfill the stringent requirements of ESMO-Magnitude Clinical Benefit Score (MCBS). Prospective novel liquid biomarker-driven studies and novel trial designs such as Umbrella and Basket trials are necessary to progress MET inhibitor development.

Comparative Effectiveness of Taxane-Containing Regimens for Treatment of HER2-Negative Metastatic Breast Cancer: A Network Meta-analysis

STUDY OBJECTIVES

To compare the effectiveness of different taxane-containing regimens and to identify the best strategy for the treatment of human epidermal growth factor receptor 2 (HER2)-negative metastatic breast cancer (MBC).

DESIGN

Network meta-analysis of 20 randomized controlled trials (RCTs).

PATIENTS

A total of 6577 patients with HER2-negative MBC who received treatment (20 different regimens) with taxanes (paclitaxel [4267 patients] or docetaxel [2310 patients]).

MEASUREMENTS AND MAIN RESULTS

The PubMed, Embase, Cochrane Library, and ClinicalTrials.gov databases were searched (through March 2019) for RCTs that evaluated any taxane-containing regimens for the treatment of HER2-negative MBC. A network meta-analysis in a Bayesian framework was performed using the random-effects model. We compared the surface under the cumulative ranking (SUCRA) curve for each regimen. Overall, paclitaxel-based combinations were superior to paclitaxel alone in objective response rate (ORR) (odds ratio 1.60, 95% credible interval [CrI] 1.15-2.16) and overall survival (OS) (hazard ratio 1.08, 95% CrI 1.01-1.15). Docetaxel-based combinations were also superior to paclitaxel alone in ORR. Among the paclitaxel-based regimens, based on the results of SUCRA, paclitaxel + bevacizumab + capecitabine was likely to be the most efficacious in improving ORR, OS, and progression-free survival (PFS), whereas paclitaxel + gemcitabine was likely to be the most efficacious in 1-year OS rate. Among the docetaxel-based regimens, based on the results of SUCRA, docetaxel + gemcitabine was likely to be the most efficacious in improving PFS and OS.

CONCLUSION

These findings demonstrated that paclitaxel-based combinations can provide significant improvement in ORR and OS compared with paclitaxel alone. The regimens of paclitaxel + bevacizumab + capecitabine, docetaxel + gemcitabine, and paclitaxel + gemcitabine may be superior to other regimens for the treatment of HER2-negative MBC.

Incidence and risk of fatigue in cancer patients treated with MET inhibitors: A systematic review and meta-analysis

BACKGROUND

The N-methyl-N'-nitroso-guanidine human osteosarcoma transforming gene (MET) inhibitors show a surprising survival benefit in the treatment of numerous tumors especially in MET-high tumor. Besides their impressive efficacy, fatigue reduced by MET inhibitors is still the safety issue during treatment. Thus, an understanding of this risk in the context of expanding MET-inhibitors use is an important cost and patient safety issue.

METHODS

We searched PubMed, Embase, and the Cochrane Library databases for relevant studies up to October 2017. Eligibility criteria included phase II/III trials of MET inhibitors that reported adequate safety profiles of fatigue. The principal summary measures were incidence and relative risk (RR) of all-grade (grade 1-4) and high-grade (grade 3-4) fatigue, respectively. Random-effects model was applied to consider within-study and between-study variation.

RESULTS

A total of 5028 patients from 17 clinical trials were identified. The results revealed that the incidences of MET inhibitors-associated all-grade and high-grade fatigue were 41.9% and 9.6%, respectively. The RR of high-grade fatigue was (RR = 1.37; 95% confidence interval, 1.14-1.66; P = .0009), whereas the RR of all-grade fatigue was (RR = 1.02; 95% confidence interval, 0.91-1.15; P = .71).

CONCLUSION

Our meta-analysis has demonstrated that MET inhibitors-based treatment is associated with an increased risk of high-grade fatigue compared with control.

Inhibition of the MET Kinase Activity and Cell Growth in MET-Addicted Cancer Cells by Bi-Paratopic Linking

MET, the product of the c-MET proto-oncogene, and its ligand hepatocyte growth factor/scatter factor (HGF/SF) control survival, proliferation and migration during development and tissue regeneration. HGF/SF-MET signaling is equally crucial for growth and metastasis of a variety of human tumors, but resistance to small-molecule inhibitors of MET kinase develops rapidly and therapeutic antibody targeting remains challenging. We made use of the designed ankyrin repeat protein (DARPin) technology to develop an alternative approach for inhibiting MET. We generated a collection of MET-binding DARPins covering epitopes in the extracellular MET domains and created comprehensive sets of bi-paratopic fusion proteins. This new class of molecules efficiently inhibited MET kinase activity and downstream signaling, caused receptor downregulation and strongly inhibited the proliferation of MET-dependent gastric carcinoma cells carrying MET locus amplifications. MET-specific bi-paratopic DARPins may represent a novel and potent strategy for therapeutic targeting of MET and other receptors, and this study has elucidated their mode of action.

Overexpression-mediated activation of MET in the Golgi promotes HER3/ERBB3 phosphorylation

Ligand-dependent oligomerization of receptor tyrosine kinases (RTKs) results in their activation through highly specific conformational changes in the extracellular and intracellular receptor domains. These conformational changes are unique for each RTK subfamily, limiting cross-activation between unrelated RTKs. The proto-oncogene MET receptor tyrosine kinase overcomes these structural constraints and phosphorylates unrelated RTKs in numerous cancer cell lines. The molecular basis for these interactions is unknown. We investigated the mechanism by which MET phosphorylates the human epidermal growth factor receptor-3 (HER3 or ERBB3), a catalytically impaired RTK whose phosphorylation by MET has been described as an essential component of drug resistance to inhibitors targeting EGFR and HER2. We find that in untransformed cells, HER3 is not phosphorylated by MET in response to ligand stimulation, but rather to increasing levels of MET expression, which results in ligand-independent MET activation. Phosphorylation of HER3 by its canonical co-receptors, EGFR and HER2, is achieved by engaging an allosteric site on the HER3 kinase domain, but this site is not required when HER3 is phosphorylated by MET. We also observe that HER3 preferentially interacts with MET during its maturation along the secretory pathway, before MET is post translationally processed by cleavage within its extracellular domain. This results in accumulation of phosphorylated HER3 in the Golgi apparatus. We further show that in addition to HER3, MET phosphorylates other RTKs in the Golgi, suggesting that this mechanism is not limited to HER3 phosphorylation. These data demonstrate a link between MET overexpression and its aberrant activation in the Golgi endomembranes and suggest that non-canonical interactions between MET and other RTKs occur during maturation of receptors. Our study highlights a novel aspect of MET signaling in cancer that would not be accessible to inhibition by therapeutic antibodies.

A Bayesian network meta-analysis of the efficacy of targeted therapies and chemotherapy for treatment of triple-negative breast cancer

Triple‐negative breast cancer (TNBC) is a heterogeneous disease with poorer prognosis than other subtypes, yet effective therapies are still not available. We aimed to compare the efficacy of various targeted therapies with chemotherapy (CT) in TNBC patients using a network meta‐analysis. A systematic literature search was performed in PubMed, EMBASE, and the Cochrane Library. A total of 27 randomized controlled trials (RCTs), involving 6924 TNBC patients, were included. Olaparib significantly improved PFS (0.43, 0.29‐0.64) and ORR (2.57, 1.31‐5.09) in comparison with CT. As for bevacizumab + CT, it showed a significant improvement of PFS (0.66, 0.55‐0.80) and ORR (2.15, 1.16‐4.05) compared with CT + placebo. It was also superior to CT alone in PFS (0.48, 0.35‐0.65) and pCR (1.30, 1.13‐1.49 for breast and axillary nodes and 1.26, 1.11‐1.44 for breast). Other targeted agents like iniparib, sorafenib, cetuximab, and ipatasertib combined with CT showed significant superiority in PFS compared with CT alone, and the HRs were 0.75 (0.62‐0.90), 0.44 (0.21‐0.91), 0.67 (0.47‐0.96), and 0.44 (0.24‐0.81), respectively, while some other agents such as sunitinib and cetuximab had the lowest SUCRA in OS, PFS, or ORR without any benefits. In conclusion, our results indicated that the addition of bevacizumab to CT was beneficial for TNBC patients, and olaparib had a great effect in PFS and ORR, especially for those with BRCA mutations. When combined with CT, targeted agents including iniparib, sorafenib, cetuximab, and ipatasertib may have better efficacies for treating TNBC.

HGF/MET and the Immune System: Relevance for Cancer Immunotherapy

An overactivation of hepatocyte growth factor (HGF)/mesenchymal-epithelial transition factor (MET) axis promotes tumorigenesis and tumor progression in various cancer types. Research data recently evidenced that HGF/MET signaling is also involved also in the immune response, mainly modulating dendritic cells functions. In general, the pathway seems to play an immunosuppressive role, thus hypothesizing that it could constitute a mechanism of primary and acquired resistance to cancer immunotherapy. Recently, some approaches are being developed, including drug design and cell therapy to combine MET and programmed cell death receptor-1 (PD-1)/programmed cell death receptor-ligand 1 (PD-L1) inhibition. This approach could represent a new weapon in cancer therapy in the future.

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.

Future Developments in Neoadjuvant Therapy for Triple-Negative Breast Cancer

Breast cancer is the 2nd leading cause of cancer-related death in women in the United States. In general, advances in targeted treatment for breast cancer have improved over the last twenty years, except in the triple-negative breast cancer (TNBC) subtype. TNBC is an aggressive breast cancer subtype with limited treatment options as compared to hormone positive breast cancers. Recently, genomic profiling of TNBC shows promise in aiding clinicians to develop personalized targeted agents. Prioritizing novel molecular-based therapies in the neoadjuvant setting may help investigators understand mechanisms of resistance and ultimately improve patient outcomes in TNBC.

Increased risk of adverse drug events secondary to bevacizumab treatment in patients with advanced or metastatic breast cancer: a meta-analysis of randomized controlled trials

Background

Several clinical trials have shown an increased risk of hypertension with bevacizumab when added to chemotherapy in different types of malignancy; however, the risks of other significant adverse events besides hypertension, specifically in breast cancer, have not been completely elucidated. This study was conducted with the aim, primarily, to assess the overall incidence and risk of common toxicities associated with bevacizumab in patients with advanced or metastatic breast cancer and, secondarily, to descriptively review study results concerning a potential correlation between bevacizumab-induced hypertension and its efficacy for breast cancer treatment.

Methods

We carried out a meta-analysis of relevant randomized controlled trials (RCTs) identified from a database search (Cochrane Library and PubMed) and, additionally, by reviewing previous reviews and meta-analyses. Overall incidence rates, odds ratios (ORs), and 95% confidence intervals (CIs) were assessed with the random- or fixed-effect models, depending on the level of heterogeneity across the included trials. The primary clinical outcomes were high-grade adverse events commonly reported with bevacizumab therapy.

Results

We included 6,260 patients with advanced-stage breast cancer from 12 RCTs in the meta-analysis. Five types of high-grade (Grade 3 or 4) adverse drug events were identified as being correlated with bevacizumab treatment versus alternative treatment with statistical significance: hypertension (OR 5.67, 95% CI 3.02–10.65), proteinuria (OR 10.09, 95% CI 4.79–21.27), bleeding (OR 3.45, 95% CI 2.25–5.30), cardiac toxicity (OR 2.15, 95% CI 1.29–3.59), and neutropenic fever (OR 1.51, 95% CI 1.15–2.00). The prognostic value of bevacizumab-induced hypertension for its antitumor efficacy among patients with breast cancer remains controversial, with mixed results presented in the five retrospective studies that were identified from our additional literature search.

Conclusion

The addition of bevacizumab to anticancer therapy was associated with a significant increase in the risk of high-grade adverse events, including hypertension, proteinuria, bleeding, cardiac toxicity, and neutropenic fever among patients with advanced-stage breast cancer. Although several retrospective studies suggested a predictive importance of hypertension secondary to bevacizumab therapy, the role of elevated blood pressure as a prognostic biomarker for its antitumor efficacy remains controversial, and further prospective trials are required to confirm such a correlation.

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.

The inhibition of UBC13 expression and blockage of the DNMT1-CHFR-Aurora A pathway contribute to paclitaxel resistance in ovarian cancer

Paclitaxel is widely used as a first-line chemotherapeutic drug for patients with ovarian cancer and other solid cancers, but drug resistance occurs frequently, resulting in ovarian cancer still presenting as the highest lethality among all gynecological tumors. Here, using DIGE quantitative proteomics, we identified UBC13 as down-regulated in paclitaxel-resistant ovarian cancer cells, and it was further revealed by immunohistochemical staining that UBC13 low-expression was associated with poorer prognosis and shorter survival of the patients. Through gene function experiments, we found that paclitaxel exposure induced UBC13 down-regulation, and the enforced change in UBC13 expression altered the sensitivity to paclitaxel. Meanwhile, the reduction of UBC13 increased DNMT1 levels by attenuating its ubiquitination, and the up-regulated DNMT1 enhanced the CHFR promoter DNA methylation levels, leading to a reduction of CHFR expression, and an increased in the levels of Aurora A. Our findings revealed a novel function for UBC13 in regulating paclitaxel sensitivity through a DNMT1-CHFR-Aurora A pathway in ovarian cancer cells. UBC13 could potentially be employed as a therapeutic molecular drug for reversing paclitaxel resistance in ovarian cancer patients.

Effect of antitumor treatments on triple-negative breast cancer patients: A PRISMA-compliant network meta-analysis of randomized controlled trials

BACKGROUND

Triple-negative breast cancer (TNBC) lacks the expression of the estrogen receptor, progesterone receptor, and receptor tyrosine-protein kinase erbB-2 (HER2/neu), which renders hormone-related endocrine and targeted therapy essentially futile.

OBJECTIVE

We performed a meta-analysis to assess the effects of antitumor regimens in the treatment of TNBC patients.

METHODS

We searched electronic databases, including PubMed, Embase, and the Cochrane Library, through January 2017 using the following keywords: "triple negative breast cancer," "TNBC," and "random*" without language restrictions. The major outcome in the present analysis was the overall response rate (ORR), and the secondary outcomes were progression-free survival (PFS) and overall survival (OS). A network meta-analysis and multilevel mixed-effects logistic regression were used to compare antitumor regimens.

RESULTS

We included 35 articles assessing a total of 8476 TNBC patients in our systematic review. The regimen of Bevacizumab, Carboplatin, and Paclitaxel (78.2%) was the most likely to improve the ORR in TNBC patients, followed by EndoTAG-1 and Paclitaxel (69.7%), Carboplatin and Paclitaxel (65.0%), and Bevacizumab and Paclitaxel (61.8%). In the patients without metastasis, the regimen of Bevacizumab, Carboplatin, and Paclitaxel (74.9%) remained the most likely to improve the ORR. We could not analyze the results for patients with metastasis or outcomes of PFS and OS because no >4 regimens formed a network. In the regression analysis, Bevacizumab (odds ratio [OR], 1.71; 95% confidence interval [CI], 1.43-2.05; P < .001) and Carboplatin (OR, 2.07; 95% CI, 1.62-2.64; P < .001) correlated with superior ORR outcome, and Iniparib (OR, 1.51; 95% CI, 1.11-2.07; P = .009) correlated with superior OS outcome.

CONCLUSION

The regimen including Bevacizumab, Carboplatin, and Paclitaxel was the most likely to improve the ORR in TNBC patients and in advanced metastatic TNBC patients. The administration of Bevacizumab and Carboplatin provided greater benefit toward improved patient ORR.

MP0250, a VEGF and HGF neutralizing DARPin® molecule shows high anti-tumor efficacy in mouse xenograft and patient-derived tumor models

Background

The VEGF/VEGFR and the HGF/cMET pathways are key mediators of the interplay of tumor cells and their microenvironment. However, inhibition of VEGF has been shown to produce only limited clinical benefit and inhibition of the activation of cMET by HGF has not translated into clinical benefit in pivotal trials. MP0250, a DARPin^® molecule that specifically inhibits both VEGF and HGF has been developed to explore the clinical potential of dual inhibition of these pathways.

Results

MP0250 binding to VEGF and HGF inhibited downstream signalling through VEGFR2 and cMET resulting in inhibition of proliferation of VEGF- and HGF-dependent cells. Antitumor activity was demonstrated in VEGF- and HGF-dependent xenograft and syngeneic models with activity superior to that of individual VEGF- and HGF-blocking DARPin^® molecules. Combination therapy studies showed potentiation of the antitumor activity of chemotherapy and immunotherapy agents, including an anti-PD1 antibody.

Materials and Methods

Potency of MP0250 was assessed in cellular models and in a variety of xenograft models as monotherapy or in combination with standard-of-care drugs.

Conclusions

Dual inhibition of VEGF and HGF by MP0250 produced powerful single agent and combination antitumor activity. This, together with increasing understanding of the role of the HGF/cMET pathway in resistance to VEGF (and other agents), supports testing of MP0250 in the clinic.

Ipatasertib plus paclitaxel versus placebo plus paclitaxel as first-line therapy for metastatic triple-negative breast cancer (LOTUS): a multicentre, randomised, double-blind, placebo-controlled, phase 2 trial

BACKGROUND

The oral AKT inhibitor ipatasertib is being investigated in cancers with a high prevalence of PI3K/AKT pathway activation, including triple-negative breast cancer. The LOTUS trial investigated the addition of ipatasertib to paclitaxel as first-line therapy for triple-negative breast cancer.

METHODS

In this randomised, placebo-controlled, double-blind, phase 2 trial, women aged 18 years or older with measurable, inoperable, locally advanced or metastatic triple-negative breast cancer previously untreated with systemic therapy were recruited from 44 hospitals in South Korea, the USA, France, Spain, Taiwan, Singapore, Italy, and Belgium. Enrolled patients were randomly assigned (1:1) to receive intravenous paclitaxel 80 mg/m² (days 1, 8, 15) with either ipatasertib 400 mg or placebo once per day (days 1-21) every 28 days until disease progression or unacceptable toxicity. Randomisation was by stratified permuted blocks (block size of four) using an interactive web-response system with three stratification criteria: previous (neo)adjuvant therapy, chemotherapy-free interval, and tumour PTEN status. The co-primary endpoints were progression-free survival in the intention-to-treat population and progression-free survival in the PTEN-low (by immunohistochemistry) population. This ongoing trial is registered with ClinicalTrials.gov (NCT02162719).

FINDINGS

Between Sept 2, 2014, and Feb 4, 2016, 166 patients were assessed for eligibility and 124 patients were enrolled and randomly assigned to paclitaxel plus ipatasertib (n=62) or paclitaxel plus placebo (n=62). Median follow-up was 10·4 months (IQR 6·5-14·1) in the ipatasertib group and 10·2 months (6·0-13·6) in the placebo group. Median progression-free survival in the intention-to-treat population was 6·2 months (95% CI 3·8-9·0) with ipatasertib versus 4·9 months (3·6-5·4) with placebo (stratified hazard ratio [HR] 0·60, 95% CI 0·37-0·98; p=0·037) and in the 48 patients with PTEN-low tumours, median progression-free survival was 6·2 months (95% CI 3·6-9·1) with ipatasertib versus 3·7 months (1·9-7·3) with placebo (stratified HR 0·59, 95% CI 0·26-1·32, p=0·18). The most common grade 3 or worse adverse events were diarrhoea (14 [23%] of 61 ipatasertib-treated patients vs none of 62 placebo-treated patients), neutrophil count decreased (five [8%] vs four [6%]), and neutropenia (six [10%] vs one [2%]). No colitis, grade 4 diarrhoea, or treatment-related deaths were reported with ipatasertib. One treatment-related death occurred in the placebo group. Serious adverse events were reported in 17 (28%) of 61 patients in the ipatasertib group and nine (15%) of 62 patients in the placebo group.

INTERPRETATION

Progression-free survival was longer in patients who received ipatasertib than in those who received placebo. To our knowledge, these are the first results supporting AKT-targeted therapy for triple-negative breast cancer. Ipatasertib warrants further investigation for the treatment of triple-negative breast cancer.

FUNDING

F Hoffmann-La Roche.

Targeting the Molecular Subtypes of Triple Negative Breast Cancer: Understanding the Diversity to Progress the Field

Triple negative breast cancers (TNBCs) represent 10%-20% of primary breast cancers, and despite having greater initial sensitivity to cytotoxic chemotherapy, patients with TNBCs have higher rates of distant metastasis and a poorer prognosis compared with patients with hormone receptor positive and/or human epidermal growth factor receptor 2 positive disease. TNBC has historically been treated as a single disease entity in targeted therapy trials, but advances in gene expression profiling and other molecular diagnostic techniques over the last decade have revealed considerable biologic heterogeneity within TNBCs, including subgroups with distinct, targetable aberrations. Such molecular heterogeneity explains, in part, the disappointing performance of targeted therapeutics in unselected TNBC. Here we discuss the history of gene expression profiling in breast cancer and its application in partitioning TNBCs into subtypes that may lead to more consistent therapeutic successes in this heterogeneous disease.

IMPLICATIONS FOR PRACTICE

Triple negative breast cancers (TNBCs) have historically been regarded as a single entity in clinical trial design. Over the last decade, molecular characterization has revealed much heterogeneity in TNBCs, explaining in part the lackluster performance of targeted therapeutics in TNBCs as a group. In this article, we review the history of the molecular classification of breast cancer based on gene expression profiling and discuss its role in TNBCs.

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.

Effect of Fluorouracil, Leucovorin, and Oxaliplatin With or Without Onartuzumab in HER2-Negative, MET-Positive Gastroesophageal Adenocarcinoma: The METGastric Randomized Clinical Trial

IMPORTANCE

Dysregulation of the mesenchymal-epithelial transition (MET) signaling pathway is associated with poor prognosis in gastroesophageal adenocarcinoma (GEC). We report results of METGastric, a phase 3 trial of the MET inhibitor onartuzumab plus standard first-line chemotherapy for human epidermal growth factor receptor 2 (HER2)-negative, MET-positive, advanced GEC.

OBJECTIVE

To determine whether the addition of onartuzumab to first-line fluorouracil, leucovorin, and oxaliplatin (mFOLFOX6) improves efficacy compared with mFOLFOX6 plus placebo in HER2-negative, MET-positive GEC.

DESIGN, SETTING, AND PARTICIPANTS

Randomized, double-blind, multicenter trial conducted from November 2012 to March 2014. Patients were 18 years or older with an adenocarcinoma of the stomach or gastroesophageal junction with metastatic disease not amenable for curative therapy. Tumor samples were centrally tested for MET expression using Ventana anti-Total c-MET (SP44) rabbit monoclonal antibody, HER2 status, and Lauren histologic subtype. MET-positive tumors were defined as at least 50% of tumor cells showing weak, moderate, and/or strong staining intensity (MET 1+/2+/3+, respectively) by immunohistochemistry.

INTERVENTIONS

Patients with HER2-negative, MET-positive GEC were enrolled and randomized 1:1 to receive mFOLFOX6 with or without onartuzumab (10 mg/kg).

MAIN OUTCOMES AND MEASURES

Co-primary end points: overall survival in the intent-to-treat (ITT) population and in patients with MET 2+/3+ GEC. Secondary end points: progression-free survival (PFS), overall response rate (ORR), and safety.

RESULTS

Enrollment was stopped early due to sponsor decision, which was agreed with an independent data monitoring committee. At the data cutoff (April 25, 2014) there were 562 patients in the ITT population (n = 283 placebo plus mFOLFOX6 [median age, 58 y; 65% male]; n = 279 onartuzumab plus mFOLFOX6 [median age, 60 y; 67% male]); 109 (38.5%) and 105 (37.6%) of the ITT population were MET 2+/3+, respectively. Addition of onartuzumab to mFOLFOX6 did not significantly improve OS, PFS, or ORR vs placebo plus mFOLFOX6 in the ITT (OS hazard ratio [HR], 0.82; 95% CI, 0.59-1.15; P = .24; PFS HR, 0.90; 95% CI, 0.71-1.16; P = .43; ORR, 46.1% vs 40.6%) or MET 2+/3+ populations (OS HR, 0.64; 95% CI, 0.40-1.03; P = .06; PFS HR, 0.79; 95% CI, 0.54-1.15; P = .22; ORR, 53.8% vs 44.6%). Safety was as expected for onartuzumab.

CONCLUSIONS AND RELEVANCE

Addition of onartuzumab to first-line mFOLFOX6 did not significantly improve clinical benefits in the ITT or MET 2+/3+ populations.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT01662869.

Progress of antibody-based inhibitors of the HGF-cMET axis in cancer therapy

Dysregulated receptor tyrosine kinase signaling in human cancer cells leads to tumor progression, invasion and metastasis. The receptor tyrosine kinase cMET is frequently overexpressed in cancer tissue, and activation of cMET signaling is related to drug resistance and the processes of carcinogenesis, invasion and metastasis. For that reason, cMET and its ligand, hepatocyte growth factor (HGF), are considered prime targets for the development of anticancer drugs. At least eight anti-cMET and four anti-HGF antibodies have been tested or are being tested in clinical trials. However, to date none of these HGF/cMET inhibitors have shown significant efficacy in clinical trials. Furthermore, no receptor tyrosine kinase inhibitors primarily targeting cMET have been approved. Given that neutralization of HGF or cMET does not cause significant adverse effects, inhibition of the HGF/cMET signaling pathway appears to be safe. In this review, we summarized the completed and ongoing clinical trials testing antibody- or protein-based anticancer drugs targeting cMET and HGF.

A Phase II Randomized Trial (GO27827) of First-Line FOLFOX Plus Bevacizumab with or Without the MET Inhibitor Onartuzumab in Patients with Metastatic Colorectal Cancer

BACKGROUND

Dysregulated hepatocyte growth factor/mesenchymal-epithelial transition (MET) signaling is associated with poor prognosis and resistance to vascular endothelial growth factor inhibition in metastatic colorectal cancer (mCRC). We report outcomes from a double-blind, multicenter phase II trial of the MET inhibitor onartuzumab in combination with mFOLFOX-6 and bevacizumab for mCRC (GO27827; NCT01418222).

MATERIALS AND METHODS

Patients were randomized 1:1 to receive onartuzumab (10 mg/kg intravenously [IV]) or placebo plus mFOLFOX-6 and bevacizumab (5 mg/kg IV). Oxaliplatin was given for 8-12 cycles; other agents were continued until disease progression, unacceptable toxicity, or death. The primary endpoint was progression-free survival (PFS) in the intent-to-treat (ITT) and MET immunohistochemistry (IHC) expression-positive populations.

RESULTS

Between September 2011 and November 2012, 194 patients were enrolled. In September 2013, an interim analysis recommended stopping onartuzumab treatment due to lack of efficacy. At the time of the final analysis in February 2014, no significant improvement in PFS was seen with onartuzumab versus placebo in either the ITT or MET IHC-positive populations. An improvement in PFS was noted in the MET IHC-negative population. Neither overall survival nor response rate was improved with onartuzumab. The incidence of fatigue, peripheral edema, and deep vein thrombosis was increased with onartuzumab relative to placebo.

CONCLUSION

Onartuzumab combined with mFOLFOX-6 and bevacizumab did not significantly improve efficacy outcomes in either the ITT or MET IHC-positive populations. MET expression by IHC was not a predictive biomarker in this setting. The Oncologist 2017;22:264-271 IMPLICATIONS FOR PRACTICE: The addition of onartuzumab to mFOLFOX-6 plus bevacizumab did not improve outcomes in patients with previously untreated metastatic colorectal cancer in this randomized, phase II study. Although initial results with onartuzumab were promising, a number of phase II/III clinical trials have reported a lack of improvement in efficacy with onartuzumab combined with standard-of-care therapies in several tumor types. Furthermore, negative study data have been published for rilotumumab and ficlatuzumab, both of which block hepatocyte growth factor binding to the mesenchymal-epithelial transition (MET) receptor. MET immunohistochemistry was not a predictive biomarker. It remains to be seen if other biomarkers or small molecule inhibitors may be more appropriate for inhibiting this oncogenic pathway.

Anti-angiogenic treatment promotes triple-negative breast cancer invasion via vasculogenic mimicry

Agents that target angiogenesis have shown limited efficacy for human triple-negative breast cancer (TNBC) in clinical trials. Along with endothelium-dependent vessels, there is also vasculogenic mimicry (VM) in the microcirculation of malignant tumors. The role of VM is not completely understood regarding anti-angiogenic treatment. In this study, human TNBC MDA-MB-231 and Hs578T and non-TNBC MCF-7 and BT474 tumor-bearing mice were treated with sunitinib, an anti-angiogenic drug, using a clinically relevant schedule. The drug was administered for one week and then discontinued. Tumor growth and invasion were observed, and the microcirculation patterns were detected with PAS/endomucin staining. Moreover, hypoxia and VM-associated proteins were evaluated with Hypoxyprobe kits and immunohistochemistry, respectively. Sunitinib significantly inhibited tumor growth in the TNBC and non-TNBC tumors. However, MDA-MB-231 and Hs578T tumors regrew and were more aggressive when the treatment was stopped. The discontinuation had no significant effect on the behavior of the non-TNBC MCF-7 and BT474 tumors. The growth of endothelium-dependent vessels in the TNBC MDA-MB-231 and Hs578T tumors were blocked by sunitinib, during which the number of VM channels significantly increased and resulted in a rebound of endothelium-dependent vessels after sunitinib discontinuation. Moreover, the VM-associated proteins VE-cadherin and Twist1 upregulated in the sunitinib-treated MDA-MB-231 and Hs578T tumors. Furthermore, the clinical significance of this upregulation was validated in 174 human breast cancers. The results from human breast cancer specimens indicated that there were more VM-positive TNBC cases than those in non-TNBC cases. HIF-1α, MMP2, VE-cadherin, and Twist1 were also expressed in a higher level in human TNBC compared with non-TNBC. In aconclusion, sunitinib promoted TNBC invasion by VM. The VM status could be helpful to predict the efficacy of anti-angiogenic therapy in patients with TNBC.

Clinical results of randomized trials and 'real-world' data exploring the impact of Bevacizumab for breast cancer: opportunities for clinical practice and perspectives for research

INTRODUCTION

Angiogenesis plays a fundamental role in breast cancer (BC) growth, progression and metastatic spread. After the promising introduction of bevacizumab for the treatment of advanced BC, the initial enthusiasm decreased when the FDA withdrew its approval in 2011. Nevertheless, several clinical studies exploring the role of bevacizumab have been subsequently published. Areas covered: The aim of this study is to review the available clinical trials exploring the potential effectiveness of bevacizumab in BC, regardless of the disease setting. Expert opinion: Even if the evidence suggests that bevacizumab must be ruled out from the HER2-positive and adjuvant setting, bevacizumab's benefit remains uncertain in the neoadjuvant setting and in the advanced treatment of HER2-negative patients. In the first setting, the addition of bevacizumab to chemotherapy increased the pathological complete response (pCR) rate in most clinical trials. However, the current absence of evidence that pCR is a trial-level surrogate for survival requires waiting for long-term results. In the advanced setting, all trials showed a benefit in progression-free survival, but not in overall survival, highlighting an increase of adverse events. The lack of predictors of response represents the main unmet need in which future clinical research will undoubtedly invest.

Phase II and Biomarker Study of Cabozantinib in Metastatic Triple-Negative Breast Cancer Patients

Currently, no targeted therapies are available for metastatic triplenegative breast cancer (mTNBC). We evaluated the safety, efficacy, and biomarkers of response to cabozantinib, a multikinase inhibitor, in patients with mTNBC. We conducted a single arm phase II and biomarker study that enrolled patients with measurable mTNBC. Patients received cabozantinib (60 mg daily) on a 3-week cycle and were restaged after 6 weeks and then every 9 weeks. The primary endpoint was objective response rate. Predefined secondary endpoints included progression-free survival (PFS), toxicity, and tissue and blood circulating cell and protein biomarkers. Of 35 patients who initiated protocol therapy, 3 (9% [95% confidence interval (CI): 2, 26]) achieved a partial response (PR). Nine patients achieved stable disease (SD) for at least 15 weeks, and thus the clinical benefit rate (PR+SD) was 34% [95% CI: 19, 52]. Median PFS was 2.0 months [95% CI: 1.3, 3.3]. The most common toxicities were fatigue, diarrhea, mucositis, and palmar-plantar erythrodysesthesia. There were no grade 4 toxicities, but 12 patients (34%) required dose reduction. Two patients had TNBCs with MET amplification. During cabozantinib therapy, there were significant and durable increases in plasma placental growth factor, vascular endothelial growth factor (VEGF), VEGF-D, stromal cell-derived factor 1a, and carbonic anhydrase IX, and circulating CD3 + cells and CD8 + T lymphocytes, and decreases in plasma soluble VEGF receptor 2 and CD14+ monocytes (all p < .05). Higher baseline concentrations of soluble MET (sMET) associated with longer PFS (p = .03). In conclusion, cabozantinib showed encouraging safety and efficacy signals but did not meet the primary endpoint in pretreated mTNBC. Exploratory analyses of circulating biomarkers showed that cabozantinib induces systemic changes consistent with activation of the immune system and antiangiogenic activity, and that sMET should be further evaluated a potential biomarker of response.

IMPLICATIONS FOR PRACTICE

Triple-negative breast cancer (TNBC)-a disease with a dearth of effective therapies-often overexpress MET, which is associated with poor clinical outcomes. However, clinical studies of agents targeting MET and VEGF pathways-alone or in combination-have shown disappointing results. This study of cabozantinib (a dual VEGFR2/MET) in metastatic TNBC, while not meeting its prespecified endpoint, showed that treatment is associated with circulating biomarker changes, and is active in a subset of patients. Furthermore, this study demonstrates that cabozantinib therapy induces a systemic increase in cytotoxic lymphocyte populations and a decrease in immunosuppressive myeloid populations. This supports the testing of combinations of cabozantinib with immunotherapy in future studies in breast cancer patients.

MET exon 14 juxtamembrane splicing mutations: clinical and therapeutical perspectives for cancer therapy

The MET proto-oncogene plays crucial roles in cell growth and proliferation, survival and apoptosis, epithelial-mesenchymal transition (EMT) and invasion, potentially conditioning the development and progression of the carcinogenesis process. The MET-associated aberrant signaling could be triggered by a variety of mechanisms, such as mutations, gene amplification, increased gene copy number and Met/HGF protein expression. Among the various MET alterations, MET exon 14 splicing abnormalities, causing the loss of the Met juxtamembrane (JM) domain, recently emerged as a new potential oncogenic driver and have been identified and validated across different cancer and histology subtypes. Moreover, this aberration was found to be mutually exclusive with other recognized drivers, thus strongly nominating its potential oncogenic role. Recently, the clinical activity of anti-Met-targeted therapy was demonstrated particularly in patients harboring MET exon 14 skipping lung cancer, resulting in a renewed enthusiasm to further test MET precision therapy in prospective trials. In this review, the key preclinical and clinical data regarding MET exon 14 skipping splicing variants as an actionable genomic aberration in cancer are described, and the perspectives deriving from the validation of such alteration as a potential target, which may further allow driving the therapeutic approach in this molecularly selected patients' subgroup, are explored.

Results From the Phase III Randomized Trial of Onartuzumab Plus Erlotinib Versus Erlotinib in Previously Treated Stage IIIB or IV Non-Small-Cell Lung Cancer: METLung

Purpose The phase III OAM4971g study (METLung) examined the efficacy and safety of onartuzumab plus erlotinib in patients with locally advanced or metastatic non-small-cell lung cancer selected by MET immunohistochemistry whose disease had progressed after treatment with a platinum-based chemotherapy regimen. Patients and Methods Patients were randomly assigned at a one-to-one ratio to receive onartuzumab (15 mg/kg intravenously on day 1 of each 21-day cycle) plus daily oral erlotinib 150 mg or intravenous placebo plus daily oral erlotinib 150 mg. The primary end point was overall survival (OS) in the intent-to-treat population. Secondary end points included median progression-free survival, overall response rate, biomarker analysis, and safety. Results A total of 499 patients were enrolled (onartuzumab, n = 250; placebo, n = 249). Median OS was 6.8 versus 9.1 months for onartuzumab versus placebo (stratified hazard ratio [HR], 1.27; 95% CI, 0.98 to 1.65; P = .067), with a greater number of deaths in the onartuzumab arm (130 [52%] v 114 [46%]). Median progression-free survival was 2.7 versus 2.6 months (stratified HR, 0.99; 95% CI, 0.81 to 1.20; P = .92), and overall response rate was 8.4% and 9.6% for onartuzumab versus placebo, respectively. Exploratory analyses using MET fluorescence in situ hybridization status and gene expression showed no benefit for onartuzumab; patients with EGFR mutations showed a trend toward shorter OS with onartuzumab treatment (HR, 4.68; 95% CI, 0.97 to 22.63). Grade 3 to 5 adverse events were reported by 56.0% and 51.2% of patients, with serious AEs in 33.9% and 30.7%, for experimental versus control arms, respectively. Conclusion Onartuzumab plus erlotinib did not improve clinical outcomes, with shorter OS in the onartuzumab arm, compared with erlotinib in patients with MET-positive non-small-cell lung cancer.

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.

Breast Cancer: A Molecular and Redox Snapshot

SIGNIFICANCE

Breast cancer is a unique disease characterized by heterogeneous cell populations causing roadblocks in therapeutic medicine, owing to its complex etiology and primeval understanding of the biology behind its genesis, progression, and sustenance. Globocan statistics indicate over 1.7 million new breast cancer diagnoses in 2012, accounting for 25% of all cancer morbidities.

RECENT ADVANCES

Despite these dismal statistics, the introduction of molecular gene signature platforms, progressive therapeutic approaches in diagnosis, and management of breast cancer has led to more effective treatment strategies and control measures concurrent with an equally reassuring decline in the mortality rate.

CRITICAL ISSUES

However, an enormous body of research in this area is requisite as high mortality associated with metastatic and/or drug refractory tumors continues to present a therapeutic challenge. Despite advances in systemic chemotherapy, the median survival of patients harboring metastatic breast cancers continues to be below 2 years.

FUTURE DIRECTIONS

Hence, a massive effort to scrutinize and evaluate chemotherapeutics on the basis of the molecular classification of these cancers is undertaken with the objective to devise more attractive and feasible approaches to treat breast cancers and improve patients' quality of life. This review aims to summarize the current understanding of the biology of breast cancer as well as challenges faced in combating breast cancer, with special emphasis on the current battery of treatment strategies. We will also try and gain perspective from recent encounters on novel findings responsible for the progression and metastatic transformation of breast cancer cells in an endeavor to develop more targeted treatment options. Antioxid. Redox Signal. 25, 337-370.

A Delphi consensus and open debate on the role of first-line bevacizumab for HER2-negative metastatic breast cancer

To gain consensus on the role of bevacizumab plus paclitaxel as first-line treatment for HER2-negative metastatic breast cancer, a panel of expert oncologists experienced in treating patients with metastatic breast cancer in Italy participated in a Delphi consensus study. The panel reached a full consensus on the efficacy of bevacizumab plus paclitaxel and the clinical meaningfulness of the progression-free survival benefit compared with paclitaxel alone, despite the lack of an overall survival effect in clinical trials. The participants agreed that real-world data support the effectiveness and well-defined safety profile of the regimen. Views on the use of bevacizumab plus paclitaxel in specific patient populations were not unanimous and clinical judgment remains important. Nevertheless, a high level of agreement was reached.

Efficacy and safety of adding an agent to bevacizumab/taxane regimens for the first-line treatment of Her2-negative patients with locally recurrent or metastatic breast cancer: results from seven randomized controlled trials

Background

The combined therapy of bevacizumab (BEV) with taxane (paclitaxel or docetaxel) has shown an improvement on progression-free survival (PFS) and objective remission in Her2-negative patients with locally recurrent or metastatic breast cancer (LR/MBC). However, there was no benefit in overall survival (OS). The aim of this study was to evaluate the efficacy and safety of adding an agent to the BEV/taxane regimens for the treatment of Her2-negative patients with LR/MBC in a first-line setting.

Materials and methods

We searched PubMed, Web of Science, EMBASE, EBSCO, and the Cochrane Library databases for eligible trials. A meta-analysis was performed using Review Manager 5.0 freeware package. We calculated the hazard ratio (HR) for PFS and OS. The odds ratio (OR) was used to calculate objective response rate (ORR) and grade 3/4 drug-related adverse events. The heterogeneity of study outcomes was calculated by the χ² test or I² statistics.

Results

A total of 1,124 patients from seven randomized controlled trials were analyzed. Our meta-analysis showed that the ORR was significantly improved in the BEV/taxane-based triplet group when compared with the BEV/taxane-based doublet group (OR =1.31, 95% confidence interval [CI]: 1.03–1.67, P=0.03). A subset analysis showed that a similar result was achieved in the triplet group in which a cytotoxic agent was added (OR =1.46, 95% CI: 1.09–1.95, P=0.01). However, the PFS and OS had no statistically significant differences between the two groups (HR =0.87, 95% CI: 0.68–1.13, P=0.31; HR =0.98, 95% CI: 0.82–1.16, P=0.78, respectively). Regarding safety, thromboembolic events, fatigue, and diarrhea (all $grade 3) were more frequently observed in the BEV/taxane-based triplet group (OR =3.8, 95% CI: 1.86–7.79, P=0.0003; OR =1.55, 95% CI: 1.05–2.27, P=0.03; OR =2.1, 95% CI: 1.29–3.41, P=0.003, respectively). Other toxic effects had no statistically significant differences between the two groups.

Conclusion

Our results showed that adding an agent to BEV/taxane treatment regimens did not significantly improve PFS and prolong OS, except for conferring a significant advantage toward improved ORR in the first-line therapy for Her2-negative patients with LR/MBC. However, its side effects are predictable and manageable.

Genomic profiling of murine mammary tumors identifies potential personalized drug targets for p53-deficient mammary cancers

Targeted therapies against basal-like breast tumors, which are typically 'triple-negative breast cancers (TNBCs)', remain an important unmet clinical need. Somatic TP53 mutations are the most common genetic event in basal-like breast tumors and TNBC. To identify additional drivers and possible drug targets of this subtype, a comparative study between human and murine tumors was performed by utilizing a murine Trp53-null mammary transplant tumor model. We show that two subsets of murine Trp53-null mammary transplant tumors resemble aspects of the human basal-like subtype. DNA-microarray, whole-genome and exome-based sequencing approaches were used to interrogate the secondary genetic aberrations of these tumors, which were then compared to human basal-like tumors to identify conserved somatic genetic features. DNA copy-number variation produced the largest number of conserved candidate personalized drug targets. These candidates were filtered using a DNA-RNA Pearson correlation cut-off and a requirement that the gene was deemed essential in at least 5% of human breast cancer cell lines from an RNA-mediated interference screen database. Five potential personalized drug target genes, which were spontaneously amplified loci in both murine and human basal-like tumors, were identified: Cul4a, Lamp1, Met, Pnpla6 and Tubgcp3 As a proof of concept, inhibition of Met using crizotinib caused Met-amplified murine tumors to initially undergo complete regression. This study identifies Met as a promising drug target in a subset of murine Trp53-null tumors, thus identifying a potential shared driver with a subset of human basal-like breast cancers. Our results also highlight the importance of comparative genomic studies for discovering personalized drug targets and for providing a preclinical model for further investigations of key tumor signaling pathways.

Recent developments and translational aspects in targeted therapy for metastatic breast cancer

Biologically distinct subtypes of metastatic breast cancer (MBC) have been defined by multiple efforts in recent years, showing broad heterogeneity at the molecular level of disease. Throughout this endeavour, oncogenic drivers within MBC were identified as potential therapeutic targets. With recent results from clinical trials targeting these well-known cancer-promoting pathways, this review is trying to elucidate as well as summarise current new therapeutic aspects in MBC and shed light on translational aspects within this entity.