A phase II trial of sorafenib in metastatic melanoma with tissue correlates

VEGF/VEGFR axis and its signaling in melanoma: Current knowledge toward therapeutic targeting agents and future perspectives

Melanoma is responsible for most skin cancer-associated deaths globally. The progression of melanoma is influenced by a number of pathogenic processes. Understanding the VEGF/VEGFR axis, which includes VEGF-A, PlGF, VEGF-B, VEGF-C, and VEGF-D and their receptors, VEGFR-1, VEGFR-2, and VEGFR-3, is of great importance in melanoma due to its crucial role in angiogenesis. This axis generates multifactorial and complex cellular signaling, engaging the MAPK/ERK, PI3K/AKT, PKC, PLC-γ, and FAK signaling pathways. Melanoma cell growth and proliferation, migration and metastasis, survival, and acquired resistance to therapy are influenced by this axis. The VEGF/VEGFR axis was extensively examined for their potential as diagnostic/prognostic biomarkers in melanoma patients and results showed that VEGF overexpression can be associated with unfavorable prognosis, higher level of tumor invasion and poor response to therapy. MicroRNAs linking to the VEGF/VEGFR axis were identified and, in this review, divided into two categories according to their functions, some of them promote melanoma angiogenesis (promotive group) and some restrict melanoma angiogenesis (protective group). In addition, the approach of treating melanoma by targeting the VEGF/VEGFR axis has garnered significant interest among researchers. These agents can be divided into two main groups: anti-VEGF and VEGFR inhibitors. These therapeutic options may be a prominent step along with the modern targeting and immune therapies for better coverage of pathological processes leading to melanoma progression and therapy resistance.

Current Advancements and Novel Strategies in the Treatment of Metastatic Melanoma

Melanoma is the deadliest form of skin cancer in the world with a growing incidence in North America. Contemporary treatments for melanoma include surgical resection, chemotherapy, and radiotherapy. However, apart from resection in early melanoma, the prognosis of patients using these treatments is typically poor. In the past decade, there have been significant advancements in melanoma therapies. Immunotherapies such as ipilimumab and targeted therapies such as vemurafenib have emerged as a promising option for patients as seen in both scientific and clinical research. Furthermore, combination therapies are starting to be administered in the form of polychemotherapy, polyimmunotherapy, and biochemotherapy, of which some have shown promising outcomes in relative efficacy and safety due to their multiple targets. Alongside these treatments, new research has been conducted into the evidence-based use of natural health products (NHPs) and natural compounds (NCs) on melanoma which may provide a long-term and non-toxic form of complementary therapy. Nevertheless, there is a limited consolidation of the research conducted in emerging melanoma treatments which may be useful for researchers and clinicians. Thus, this review attempts to evaluate the therapeutic efficacy of current advancements in metastatic melanoma treatment by surveying new research into the molecular and cellular basis of treatments along with their clinical efficacy. In addition, this review aims to elucidate novel strategies that are currently being used and have the potential to be used in the future.

Optimal treatment strategy for metastatic melanoma patients harboring BRAF-V600 mutations

BRAF-V600 mutations occur in approximately 50% of patients with metastatic melanoma. Immune-checkpoint inhibitors and targeted therapies are both active as first-line treatments in these patients regardless of their mechanisms of action and toxicities. However, an upfront therapeutic strategy is still controversial. In fact, waiting for results of ongoing clinical trials and for new biomarkers, clinicians should base their decision on the clinical characteristics of the patient and on the biological aspects of the tumor. This review provides an overview on BRAF-V600 mutations in melanoma and will discuss their prognostic and clinical significance. Moreover, it will suggest a therapeutic algorithm that can drive therapeutic choice in a first-line setting for BRAF-V600 mutant melanoma patients.

An update on the implications of cyclin D1 in melanomas

Cyclin D1 is a protein encoded by the CCND1 gene, located on 11q13 chromosome, which is a key component of the physiological regulation of the cell cycle. CCND1/cyclin D1 is upregulated in several types of human tumors including melanoma and is currently classified as an oncogene that promotes uncontrolled cell proliferation. Despite the demonstrated importance of CCND1/cyclin D1 as a central oncogene in several types of human tumors, its knowledge in melanoma is still limited. This review examines data published on upregulation of the CCND1 gene and cyclin D1 protein in the melanoma setting, focusing on the pathways and molecular mechanisms involved in the activation of the gene and on the clinical and therapeutic implications.

Epigenetic Mechanisms of Escape from BRAF Oncogene Dependency

About eight percent of all human tumors (including 50% of melanomas) carry gain-of-function mutations in the BRAF oncogene. Mutated BRAF and subsequent hyperactivation of the MAPK signaling pathway has motivated the use of MAPK-targeted therapies for these tumors. Despite great promise, however, MAPK-targeted therapies in BRAF-mutant tumors are limited by the emergence of drug resistance. Mechanisms of resistance include genetic, non-genetic and epigenetic alterations. Epigenetic plasticity, often modulated by histone-modifying enzymes and gene regulation, can influence a tumor cell's BRAF dependency and therefore, response to therapy. In this review, focusing primarily on class 1 BRAF-mutant cells, we will highlight recent work on the contribution of epigenetic mechanisms to inter- and intratumor cell heterogeneity in MAPK-targeted therapy response.

Neuroblastoma rat sarcoma mutated melanoma: That's what we got so far

Neuroblastoma rat sarcoma (NRAS) mutation, occurring in about 20%-30% of cutaneous melanomas, leads to activation of RAS-RAF-MAPK cascade and represents a clear distinct clinicopathological entity in melanoma. In contrast with BRAF mutant melanoma, no specific target therapies are available outside the setting of clinical trials. In the field of immunoncology, the predictive role of NRAS mutation with respect to checkpoint inhibitors treatment has not clearly established and deserves further investigation. At present, the standard treatment is the same as for BRAF wild type melanoma. Ongoing trials are exploring novel combination strategies among patients with advanced NRAS mutant melanoma.

Two synchronous malignancies: nodular melanoma and renal cell carcinoma in a patient with an underlying germline BRCA2 mutation

Modernised genetic testing among patients with cancer has led to an increasing wealth of knowledge regarding cancer biology and aetiology. Furthermore, some germline mutations have the potential to direct therapeutic approaches as well. While BRCA1/2 mutations are well-established risk factors for breast and ovarian cancers, their impact on other cancers is less understood. We describe a patient with a germline BRCA2 mutation who developed synchronous melanoma and renal cell carcinoma, but responded well to treatment and is now cancer free.

Developments in the Space of New MAPK Pathway Inhibitors for BRAF-Mutant Melanoma

The characterization of the MAPK signaling pathway has led to the development of multiple promising targeted therapy options for a subset of patients with metastatic melanoma. The combination of BRAF and MEK inhibitors represents an FDA-approved standard of care in patients with metastatic and resected BRAF-mutated melanoma. There are currently three FDA-approved BRAF/MEK inhibitor combinations for the treatment of patients with BRAF-mutated melanoma. Although there have been significant advances in the field of targeted therapy, further exploration of new targets within the MAPK pathway will strengthen therapeutic options for patients. Important clinical and translational research focuses on mechanisms of resistance, predictive biomarkers, and challenging patient populations such as those with brain metastases or resected melanoma.

DNA methylation alterations as therapeutic prospects in thyroid cancer

BACKGROUND

Thyroid cancer is one of the most common endocrine malignancies. Although the 10-year survival rate of differentiated thyroid cancer (DTC) is about 90% after conventional treatments, a small proportion of patients still suffer from tumor recurrence or drug resistance.

OBJECTIVE

This review article summarizes recent researches and clinical trials related to target drugs that reduce mortality in thyroid cancer.

METHODS

This is a review of the recent literature and clinical trials on the three main aspects including methylation genes in thyroid cancers, the relationship between BRAF mutation and gene methylation, target and dehypermethylation drugs in clinical trials.

RESULTS

We propose new approaches to treating malignant thyroid cancer, based on advances in understanding the relationship between genetic and epigenetic changes in thyroid cancer. Although the effect of traditional treatment for thyroid cancer is relatively good, a small proportion of patients still suffer from tumor recurrence or drug resistance. Molecular targeted drugs and dehypermethylation drugs have more promising outcomes in aggressive thyroid cancer compared with conventional treatments.

CONCLUSION

Based on what was discussed in this review, we suggest that integration of epigenetic and targeted therapies into conventional treatments will reduce the occurrence of refractory radioiodine differentiated thyroid cancer and improve the outcomes in aggressive thyroid cancer patients.

Adjuvant Therapy for Resected Stage III Melanoma Patients: High-Dose Interferon-Alpha versus Ipilimumab Combined with Kinases Inhibitors

High-dose interferon-alpha remains the first-line treatment in the adjuvant therapy of metastatic melanoma. More recently, high-dose pegylated interferon-alpha-2b has been approved by the US Food and Drug Administration. Actually, an adjuvant therapy alternative to high-dose interferon-alpha is represented by ipilimumab. Moreover, combination therapy of IFN-alpha or ipilimumab with tyrosine kinase inhibitors has been proved in patients with specific mutations. It is mandatory to understand what the best adjuvant treatment is for resected metastatic melanoma patients, particularly at stage III-N1, in terms of overall survival rather than recurrence-free survival. The ECOG 1609 clinical trial compared high-dose interferon-alpha and ipilimumab alone or combined with tyrosine kinase inhibitors for the treatment of early metastatic melanoma. In the past, ECOG 1684, 1690 and 1694 trials showed improvement in recurrence-free survival more than overall survival for high-risk melanoma patients (stage IIB-III) treated with high-dose interferon-alpha, whereas more recently the EORTC 18991 trial reported successful therapeutic results in terms of recurrence-free survival rather than overall survival for stage III-N1 melanoma patients treated with high-dose pegylated interferon-alpha-2b. Toxicity was more acceptable within one year of treatment. Randomized trials have demonstrated that ipilimumab as second-line therapy is able to increase dose-dependent overall survival rates in advanced melanoma patients despite severe but reversible immune-related adverse events. Old tyrosine kinase inhibitors have been used in combination with interferon for the treatment of advanced melanoma patients with moderate benefits and increased toxicity, but new selective drugs seem to be more efficacious. Early metastatic melanoma patients (stage III-N1) should be the principal subset to be treated with the most suitable adjuvant therapy to achieve the best overall survival. New schedules have to be tested with high-dose interferon-alpha and ipilimumab alone or combined with tyrosine kinase inhibitors while waiting for results from ECOG 1609.

Safety, tolerability, and pharmacokinetic profile of dabrafenib in Japanese patients with BRAF V600 mutation-positive solid tumors: a phase 1 study

Background Dabrafenib is a BRAF inhibitor that has demonstrated clinical activity with a good tolerability profile in patients with BRAF ^V600E mutated metastatic melanoma. This study evaluated the safety and tolerability, pharmacokinetics and preliminary efficacy of dabrafenib in Japanese patients. Methods This phase I, open-label, dose escalation study was conducted in 12 Japanese patients with BRAF ^V600 mutation positive solid tumours. Primary endpoint was safety, assessed by monitoring and recording of all adverse events (AEs), serious AEs, drug-related AEs; secondary endpoints were pharmacokinetic profiles and efficacy measured by tumour response. This study is registered with ClinicalTrials.gov, number NCT01582997. Results Of the 12 patients enrolled, 3 each received 75 mg and 100 mg dabrafenib while 6 received 150 mg dabrafenib twice daily orally. Melanoma and thyroid cancer were the primary tumours reported in 11 (92%) and 1 (8%) patients respectively. Most AEs were grade 1 or 2 and considered related to study treatment. Most common AEs reported in the 12 patients were alopecia in 7 (58%); pyrexia, arthralgia and leukopenia in 6 (50%) each, hyperkeratosis and nausea in 4 (33%) each. Partial response as best overall response was reported in 7 of 12 (58%) patients and in 6 (55%) with malignant melanoma. No dose-limiting toxicity (DLTs) were reported during the DLT evaluation periods. Conclusions Dabrafenib was well tolerated and rapidly absorbed administered as single- or multiple dose. Comparable safety and pharmacokinetic profiles were observed compared with non-Japanese patients. Dabrafenib has promising clinical activity in Japanese patients with BRAF mutated malignant melanoma.

Antiangiogenic tyrosine kinase inhibitors in colorectal cancer: is there a path to making them more effective?

Antiangiogenic therapy has a proven survival benefit in metastatic colorectal cancer. Inhibition of the VEGF pathway using a variety of extracellular antibody approaches has clear benefit in combination with chemotherapy, while intracellular blockade using tyrosine kinase inhibitors (TKIs) such as sorafenib and regorafenib has had more limited success. Pharmacodynamic modeling using modalities such as DCE-MRI indicates potent antiangiogenic effects of these TKIs, yet numerous combination therapies, primarily with chemotherapy, have failed to demonstrate an additive benefit. The sole comparative study of a single agent TKI against placebo showed a survival benefit of regorafenib in patients with advanced, refractory disease. Preclinical data demonstrate synergy between antiantiogenic TKIs and targeted interventions including autophagy inhibition, and together with a renewed effort to define markers of susceptibility, such combinations may be a way to improve the limited efficacy of this once-promising drug class.

Emerging growth factor receptor antagonists for the treatment of advanced melanoma

INTRODUCTION

Therapy for metastatic melanoma has undergone a rapid transformation over the past 5-10 years. Advances in immunotherapy with checkpoint inhibitors, including both anti-CTLA-4 and anti-PD-1/PD-L1, have led to durable responses in up to 50% of patients. As our understanding of the processes driving the transformation of melanocytes has improved, progress in targeted therapies has also continued. Areas covered: Angiogenesis and the tumor's dependence on an expanded vascular supply has been a target for novel therapies since the 1970's, as this tissue is derived from endothelial cells that are genetically stable in adults. A phase II trial studying combined therapy with bevacizumab (an inhibitor of angiogenesis) and ipilimumab found promising results. Other agents such as sorafenib have not been as successful, failing to extend progression free or overall survival in clinical trials. In this paper other targeted growth factor inhibitors will also be discussed. Expert opinion: Ultimately, melanoma may not be vulnerable solely to chemotherapy or targeted therapy, but may be efficaciously treated with immunotherapy due to its high mutational rate resulting in the expression of numerous neo-antigens. Therapies with combinations of agents including growth factor receptor and either other targeted therapies or immunotherapy may be a promising complimentary approach.

Regulation of Ras signaling and function by plasma membrane microdomains

Together H-, N- and KRAS mutations are major contributors to ~30% of all human cancers. Thus, Ras inhibition remains an important anti-cancer strategy. The molecular mechanisms of isotypic Ras oncogenesis are still not completely understood. Monopharmacological therapeutics have not been successful in the clinic. These disappointing outcomes have led to attempts to target elements downstream of Ras, mainly targeting either the Phosphatidylinositol 3-Kinase (PI3K) or Mitogen-Activated Protein Kinase (MAPK) pathways. While several such approaches are moderately effective, recent efforts have focused on preclinical evaluation of combination therapies to improve efficacies. This review will detail current understanding of the contributions of plasma membrane microdomain targeting of Ras to mitogenic and tumorigenic signaling and tumor progression. Moreover, this review will outline novel approaches to target Ras in cancers, including targeting schemes for new drug development, as well as putative re-purposing of drugs in current use to take advantage of blunting Ras signaling by interfering with Ras plasma membrane microdomain targeting and retention.

Inefficiencies and Patient Burdens in the Development of the Targeted Cancer Drug Sorafenib: A Systematic Review

Failure in cancer drug development exacts heavy burdens on patients and research systems. To investigate inefficiencies and burdens in targeted drug development in cancer, we conducted a systematic review of all prelicensure trials for the anticancer drug, sorafenib (Bayer/Onyx Pharmaceuticals). We searched Embase and MEDLINE databases on October 14, 2014, for prelicensure clinical trials testing sorafenib against cancers. We measured risk by serious adverse event rates, benefit by objective response rates and survival, and trial success by prespecified primary endpoint attainment with acceptable toxicity. The first two clinically useful applications of sorafenib were discovered in the first 2 efficacy trials, after five drug-related deaths (4.6% of 108 total) and 93 total patient-years of involvement (2.4% of 3,928 total). Thereafter, sorafenib was tested in 26 indications and 67 drug combinations, leading to one additional licensure. Drug developers tested 5 indications in over 5 trials each, comprising 56 drug-related deaths (51.8% of 108 total) and 1,155 patient-years (29.4% of 3,928 total) of burden in unsuccessful attempts to discover utility against these malignancies. Overall, 32 Phase II trials (26% of Phase II activity) were duplicative, lacked appropriate follow-up, or were uninformative because of accrual failure, constituting 1,773 patients (15.6% of 11,355 total) participating in prelicensure sorafenib trials. The clinical utility of sorafenib was established early in development, with low burden on patients and resources. However, these early successes were followed by rapid and exhaustive testing against various malignancies and combination regimens, leading to excess patient burden. Our evaluation of sorafenib development suggests many opportunities for reducing costs and unnecessary patient burden in cancer drug development.

The cutting edge of metastatic melanoma therapy

The past decade has witnessed impressive new developments for the treatment of melanoma. The discovery of key oncogenic driver mutations, upon which tumor establishment and progression are dependent, changed the prognosis of patients with stage IV disease. Extensive preclinical and clinical studies have shown high response rates and survival benefits over conventional chemotherapies provided by target-specific inhibitors of BRAF- or NRAS-activating mutations. Recent genomic analyses of melanoma have also given new potentially targetable driver mutations. In addition, the quickened pace of development of immune checkpoint inhibitors for the treatment of melanoma offers the unique opportunity to provide a long-term clinical benefit. In this emerging era, predictive biomarkers for the selection of patients are required to help us develop an optimal therapeutic strategy.

Design and Reporting of Targeted Anticancer Preclinical Studies: A Meta-Analysis of Animal Studies Investigating Sorafenib Antitumor Efficacy

The validity of preclinical studies of candidate therapeutic agents has been questioned given their limited ability to predict their fate in clinical development, including due to design flaws and reporting bias. In this study, we examined this issue in depth by conducting a meta-analysis of animal studies investigating the efficacy of the clinically approved kinase inhibitor, sorafenib. MEDLINE, Embase, and BIOSIS databases were searched for all animal experiments testing tumor volume response to sorafenib monotherapy in any cancer published until April 20, 2012. We estimated effect sizes from experiments assessing changes in tumor volume and conducted subgroup analyses based on prespecified experimental design elements associated with internal, construct, and external validity. The meta-analysis included 97 experiments involving 1,761 animals. We excluded 94 experiments due to inadequate reporting of data. Design elements aimed at reducing internal validity threats were implemented only sporadically, with 66% reporting animal attrition and none reporting blinded outcome assessment or concealed allocation. Anticancer activity against various malignancies was typically tested in only a small number of model systems. Effect sizes were significantly smaller when sorafenib was tested against either a different active agent or combination arm. Trim and fill suggested a 37% overestimation of effect sizes across all malignancies due to publication bias. We detected a moderate dose-response in one clinically approved indication, hepatocellular carcinoma, but not in another approved malignancy, renal cell carcinoma, or when data were pooled across all malignancies tested. In support of other reports, we found that few preclinical cancer studies addressed important internal, construct, and external validity threats, limiting their clinical generalizability. Our findings reinforce the need to improve guidelines for the design and reporting of preclinical cancer studies. Cancer Res; 76(16); 4627-36. ©2016 AACR.

Preclinical and first-in-human phase I studies of KW-2450, an oral tyrosine kinase inhibitor with insulin-like growth factor receptor-1/insulin receptor selectivity

Numerous solid tumors overexpress or have excessively activated insulin-like growth factor receptor-1 (IGF-1R). We summarize preclinical studies and the first-in-human study of KW-2450, an oral tyrosine kinase inhibitor with IGF-1R and insulin receptor (IR) inhibitory activity. Preclinical activity of KW-2450 was evaluated in various in vitro and in vivo models. It was then evaluated in a phase I clinical trial in 13 patients with advanced solid tumors (NCT00921336). In vitro, KW-2450 inhibited human IGF-1R and IR kinases (IC50 7.39 and 5.64 nmol/L, respectively) and the growth of various human malignant cell lines. KW-2450 40 mg/kg showed modest growth inhibitory activity and inhibited IGF-1-induced signal transduction in the murine HT-29/GFP colon carcinoma xenograft model. The maximum tolerated dose of KW-2450 was 37.5 mg once daily continuously; dose-limiting toxicity occurred in two of six patients at 50 mg/day (both grade 3 hyperglycemia) and in one of seven patients at 37.5 mg/day (grade 3 rash). Four of 10 evaluable patients showed stable disease. Single-agent KW-2450 was associated with modest antitumor activity in heavily pretreated patients with solid tumors and is being further investigated in combination therapy with lapatinib/letrozole in patients with human epidermal growth factor receptor 2-postive metastatic breast cancer.

Targeted Therapy for Melanoma

Vemurafenib and dabrafenib, two potent tyrosine kinase inhibitors (TKIs) of the BRAF(V600E) kinase, are highly effective in the treatment of a BRAF (V600) -mutant metastatic melanoma. These are selective type I inhibitors (functional against the active conformation of the kinase) of the RAF kinases, which are key players in the mitogen-activated protein kinase (MAPK) pathway. BRAF (V600) mutations are present in approximately 7 % of all cancers, including high frequencies of mutations reported in 50 % of advanced melanomas and 100 % of hairy cell leukemias. As with most targeted therapies, resistance to BRAF inhibitors is an issue, and mechanisms of resistance are varied. Combining BRAF inhibitors with MEK inhibitors such as trametinib delays the development of resistance. Rationally combining targeted therapies to address the mechanism of resistance or combining BRAF inhibitors with other effective therapies such as immunotherapy may result in further improvement in outcomes for patients.

Targeted Therapies in Melanoma: Translational Research at Its Finest

The therapeutic landscape for advanced melanoma has expanded in recent years. This expansion has largely been driven by investigational work in melanoma tumor biology and immunology that has been successfully translated to the clinical setting. Molecular evidence generated through benchside experimentation identified BRAF and MEK as key molecular targets in melanoma. This commentary will highlight this work and provide a rationale for the continued importance of translational work in the field of targeted melanoma therapies.

Convection-enhanced delivery of sorafenib and suppression of tumor progression in a murine model of brain melanoma through the inhibition of signal transducer and activator of transcription 3

OBJECT Despite recent advances, metastatic melanoma remains a terminal disease, in which life-threatening brain metastasis occurs in approximately half of patients. Sorafenib is a multikinase inhibitor that induces apoptosis of melanoma cells in vitro. However, systemic administration has been ineffective because adequate tissue concentrations cannot be achieved. This study investigated if convection-enhanced delivery (CED) of sorafenib would enhance tumor control and survival via inhibition of the signal transducer and activator of transcription 3 (Stat3) pathway in a murine model of metastatic brain melanoma. METHODS Melanoma cells treated with sorafenib in vitro were examined for signaling and survival changes. The effect of sorafenib given by CED was assessed by bioluminescent imaging and animal survival. RESULTS The results showed that sorafenib induced cell death in the 4 established melanoma cell lines and in 1 primary cultured melanoma cell line. Sorafenib inhibited Stat3 phosphorylation in HTB65, WYC1, and B16 cells. Accordingly, sorafenib treatment also decreased expression of Mcl-1 mRNA in melanoma cell lines. Because sorafenib targets multiple pathways, the present study demonstrated the contribution of the Stat3 pathway by showing that mouse embryonic fibroblast (MEF) Stat3 +/+ cells were significantly more sensitive to sorafenib than MEF Stat3 -/- cells. In the murine model of melanoma brain metastasis used in this study, CED of sorafenib increased survival by 150% in the treatment group compared with animals receiving the vehicle control (p < 0.01). CED of sorafenib also significantly abrogated tumor growth. CONCLUSIONS The data from this study indicate that local delivery of sorafenib effectively controls brain melanoma. These findings validate further investigation of the use of CED to distribute molecularly targeted agents.

Multifunctional bioscaffolds for 3D culture of melanoma cells reveal increased MMP activity and migration with BRAF kinase inhibition

Matrix metalloproteinases (MMPs) are important for many different types of cancer-related processes, including metastasis. Understanding the functional impact of changes in MMP activity during cancer treatment is an important facet not typically evaluated as part of preclinical research. With MMP activity being a critical component of the metastatic cascade, we designed a 3D hydrogel system to probe whether pharmacological inhibition affected human melanoma cell proteolytic activity; metastatic melanoma is a highly aggressive and drug-resistant form of skin cancer. The relationship between MMP activity and drug treatment is unknown, and therefore we used an in situ fluorogenic MMP sensor peptide to determine how drug treatment affects melanoma cell MMP activity in three dimensions. We encapsulated melanoma cells from varying stages of progression within PEG-based hydrogels to examine the relationship between drug treatment and MMP activity. From these results, a metastatic melanoma cell line (A375) and two inhibitors that inhibit RAF (PLX4032 and sorafenib) were studied further to determine whether changes in MMP activity led to a functional change in cell behavior. A375 cells exhibited increased MMP activity despite an overall decrease in metabolic activity with PLX4032 treatment. The changes in proteolytic activity correlated with increased cell elongation and increased single-cell migration. In contrast, sorafenib did not alter MMP activity or cell motility, showing that the changes induced by PLX4032 were not a universal response to small-molecule inhibition. Therefore, we argue the importance of studying MMP activity with drug treatment and its possible implications for unwanted side effects.

Blinded by the light: why the treatment of metastatic melanoma has created a new paradigm for the management of cancer

Until recently, treatment for metastatic melanoma was characterised by a limited availability of treatment options that offer objective survival benefit. Cytotoxic agents fundamentally lack the ability to achieve disease control and cytokine therapy with interleukin-2 has an unacceptably high - for the use across all patient cohorts - rate of toxicities. The validation of braf as an oncogene driving melanoma tumorigenesis, as well as the discovery of the role of CTLA-4 receptor in the evasion of anticancer immune response by melanoma, has revolutionised our treatment options against a disease with dismal prognosis. Quick implementation of translational discoveries brought about BRAF/MEK inhibition in clinic, while at the same time, wider experience with CTLA-4 blockade enabled clinicians to manage previously fatal immune-related toxicities with greater confidence. The suitability for clinical use of other oncogenic drivers such as NRAS and c-kit is currently being tested whilst the PD-1/PD-L1/PD-L2 axis has emerged as a new immunotherapy target with exciting early phase results. The recent exponential progress in treatment of melanoma has set an example of translational medicine and the current review aims to explain why, as well as suggesting new goals for the future.

BRAF and MEK inhibition in melanoma

INTRODUCTION

Selective inhibition of the MAPK pathway with either BRAF or MEK inhibition has emerged as a key component for the treatment of BRAF-mutant metastatic melanoma. New evidence suggests that the combination of BRAF and MEK inhibitors improves tumor response rate and progression-free survival, while potentially attenuating some of the serious adverse events observed with monotherapy.

AREAS COVERED

This review covers the current data on the efficacy and safety of the selective BRAF (vemurafenib and dabrafenib) and MEK (trametinib) inhibitors as well as the available data on BRAF inhibitor + MEK inhibitor combination therapy (dabrafenib + trametinib and vemurafenib + cobimetinib). The efficacy, safety and toxicity data are discussed from Phase I, Phase II and Phase III trials of these drugs.

EXPERT OPINION

Combination therapy with the BRAF and MEK inhibitors improves response rates and progression-free survival in patients with BRAF-mutant metastatic melanoma. Some of the serious adverse events, in particular, the incidence of cutaneous squamous cell carcinoma, are attenuated with combination therapy, whereas milder side effects such as pyrexia can be more common with combination therapy. Although dose reductions and dose interruptions are slightly more common with combination therapy, overall data supports the notion that combination therapy is safe and improves the outcomes for patients compared to single agent BRAF inhibitors.

Advances in targeted therapy for unresectable melanoma: new drugs and combinations

Melanoma is the most deadly cutaneous cancer primarily derived from melanocytes with a poor prognosis in advanced stage. The therapy regimen for early stage melanoma patients is surgical resection with adjuvant IFN-alpha-2b therapy. For metastatic lesions, standard chemotherapy such as dacarbazine (DTIC) has not achieved a satisfying response rate. Therefore, new approaches to manage this deadly disease are highly expected to enhance the cure rate and to extend clinical benefits to patients with unresectable melanoma. Fortunately, the targeted therapeutic drugs and immunotherapy such as vemurafenib, dabrafenib, ipilimumab, and trametinib have shown their special advantage in the treatment of advanced melanoma. This article is to overview the advances in targeted therapy for unresectable melanoma patients.

In vivo profiling reveals immunomodulatory effects of sorafenib and dacarbazine on melanoma

Sorafenib is a multi-kinase inhibitor used alone or in combination with dacarbazine to treat metastasized melanoma. Our study investigated the relationship between metabolic response assessed by PET-CT and global transcriptome changes during sorafenib and dacarbazine therapy in patients with advanced melanoma. We conducted an open-label, investigator-initiated study that enrolled 13 sorafenib-naïve Stage IV melanoma patients, whose metastases were accessible for repeated biopsies. Treatment regimen included orally administered sorafenib and intravenous dacarbazine. Biopsies of skin or superficial lymph node metastases were taken before treatment (baseline), during sorafenib and after dacarbazine therapy and used for transcriptional profiling and validation experiments. Serum samples were evaluated for cytokine production. Metabolic response to therapy was observed in 45.5% of patients. The study drugs were well tolerated. We observed a clear upregulation of interferon (IFN)-stimulated immune response genes in profiled metastases. The IFNγ-induced gene signature seemed to be enhanced after addition of dacarbazine to sorafenib. Serum IFNγ also increased during therapy, particularly after addition of dacarbazine. Induction of IFNγ stimulated genes correlating with increased serum IFNγ was predictive of better clinical outcome and responders who had significantly higher serum IFNγ levels lived longer. Our data reveal in situ changes in melanoma metastases during treatment with sorafenib and dacarbazine and suggest an additional mechanism of action through immunomodulation.

Converting biology into clinical benefit: lessons learned from BRAF inhibitors

The identification and pharmacological targeting of activating BRAF mutations in melanoma has led to significant improvements in patient outcomes. This perspective paper illustrates the lessons learned from the study of BRAF mutations and the development of BRAF inhibitors. The relevance of these lessons to the development of future targeted therapies is highlighted.

Incidence and risk of sorafenib-induced hypertension: a systematic review and meta-analysis

Hypertension is one of the major side effects of sorafenib, and reported incidences vary substantially among clinical trials. A systematic review was conducted using Medline, PubMed, Embase, and the Cochrane Library for all longitudinal studies to investigate the incidence and risk of hypertension events in cancer patients treated with sorafenib. A total of 14 randomized controlled trials and 39 prospective single-arm trials involving 13,555 patients were selected for the meta-analysis. The relative risk of all-grade and high-grade hypertension associated with sorafenib were 3.07 (95% confidence interval [CI], 2.05–4.60; P<.01) and 3.31 (95% CI, 2.21–4.95; P<.01), respectively. The overall incidence of sorafenib-induced all-grade and high-grade hypertension were 19.1% (95% CI, 15.8%–22.4%) and 4.3% (95% CI, 3.0%–5.5%), respectively. A significantly higher incidence of hypertension was noted in patients with renal cell carcinoma (RCC) compared with those with non-RCC malignancies (all-grade: 24.9% [95% CI, 19.7%–30.1%] vs 15.7%[95% CI, 12.1%–19.3%]; P<.05; high-grade:8.6% [95% CI, 6.0%–11.2%] vs 1.8% [95% CI, 0.9%–2.6%]; P<.05). The trials with median progression-free survival (PFS) longer than 5.3 months (mean PFS) demonstrated a significantly higher incidence of high-grade hypertension than trials with shorter PFS (6.3% [95% CI, 4.1%–8.5%] vs 2.6% [95% CI, 1.4%– 3.8%]; P<.05). Findings of the meta-analysis indicated a significantly high risk of sorafenib-induced hypertension. Patients with RCC have a significantly higher incidence of hypertension and the occurrence of hypertension may be associated with improved prognosis.

Mechanisms of tumour vascularization in cutaneous malignant melanoma: clinical implications

Malignant melanoma represents < 10% of all skin cancers but is responsible for the majority of skin-cancer-related deaths. Metastatic melanoma has historically been considered as one of the most therapeutically challenging malignancies. Fortunately, for the first time after decades of basic research and clinical investigation, new drugs have produced major clinical responses. Angiogenesis has been considered an important target for cancer treatment. Initial efforts have focused primarily on targeting endothelial and tumour-related vascular endothelial growth factor signalling. Here, we review different mechanisms of tumour vascularization described in melanoma and discuss the potential clinical implications.

Correlation of somatic mutations and clinical outcome in melanoma patients treated with Carboplatin, Paclitaxel, and sorafenib

PURPOSE

Sorafenib is an inhibitor of VEGF receptor (VEGFR), platelet-derived growth factor receptor (PDGFR), and RAF kinases, amongst others. We assessed the association of somatic mutations with clinicopathologic features and clinical outcomes in patients with metastatic melanoma treated on E2603, comparing treatment with carboplatin, paclitaxel ± sorafenib (CP vs.

CPS) EXPERIMENTAL DESIGN

Pretreatment tumor samples from 179 unique individuals enrolled on E2603 were analyzed. Genotyping was performed using a custom iPlex panel interrogating 74 mutations in 13 genes. Statistical analysis was performed using Fisher exact test, logistic regression, and Cox proportional hazards models. Progression-free survival (PFS) and overall survival were estimated using Kaplan-Meier methods.

RESULTS

BRAF and NRAS mutations were found at frequencies consistent with other metastatic melanoma cohorts. BRAF-mutant melanoma was associated with worse performance status, increased number of disease sites, and younger age at diagnosis. NRAS-mutant melanoma was associated with better performance status, fewer sites of disease, and female gender. BRAF and NRAS mutations were not significantly predictive of response or survival when treated with CPS versus CP. However, patients with NRAS-mutant melanoma trended toward a worse response and PFS on CP than those with BRAF-mutant or WT/WT melanoma, an association that was reversed for this group on the CPS arm.

CONCLUSIONS

This study of somatic mutations in melanoma is the last prospectively collected phase III clinical trial population before the era of BRAF-targeted therapy. A trend toward improved clinical response in patients with NRAS-mutant melanoma treated with CPS was observed, possibly due to the effect of sorafenib on CRAF.

Insight into the structural features of pyrazolopyrimidine- and pyrazolopyridine-based B-Raf(V600E) kinase inhibitors by computational explorations

Presently, both ligand-based and receptor-based 3D-QSAR modelings were performed on 107 pyrazolopyrimidine- and pyrazolopyridine-based inhibitors of B-Raf(V600E) kinase. The optimal model is successful to predict the inhibitors' activity with Q(2) of 0.504, R(2) ncv of 0.960, and R(2) pred of 0.872. Besides, the 3D contour maps explain well the structural requirements of the interaction between the ligand and the receptor. Furthermore, molecular docking and MD were also carried out to study the binding mode. Our findings are the following: (i) Bulky substituents at position 3, 10 and ring D improve the inhibitory activity, but impair the activity at position 5, 11, and 19. (ii) Electropositive groups at position 10, 13 and 20 and electronegative groups at position 2 increase the biological activity. (iii) Hydrophobic substituents at ring C are beneficial to improve the biological activity, while hydrophilic substituents at position 11 and ring D are good for the activity. (4) This scaffold of inhibitors may bind to the B-Raf kinase with an 'L' conformation and belong to type III binding mode, which is fixed by hydrophobic interaction and hydrogen bonds with residues from hinge region and DFG motif. These results may be a guidance to develop new B-Raf(V600E) kinase inhibitors.

MEK inhibition in the treatment of advanced melanoma

The RAS-RAF-MEK-ERK pathway is considered to be the most important signal transduction pathway in melanoma, and alterations in this pathway via various genetic mutations, such as BRAF and NRAS mutations, are known to be important drivers of melanomagenesis. As MEK is an essential intermediary kinase protein within this pathway, inhibition of MEK has been of a great interest as a molecular target therapy in melanoma. In fact, trametinib, a selective MEK inhibitor, has been shown to have a survival benefit over cytotoxic chemotherapy in patients with V600 BRAF-mutant metastatic melanoma, leading to the FDA approval for this patient population. MEK inhibitors may also be useful in treatment of advanced melanoma harboring other genetic mutations, such as NRAS and GNAQ/GNA11 mutations. Here, we review and discuss the preclinical and clinical data regarding MEK inhibitors and their role in the treatment of advanced melanoma.

Monitoring chemotherapeutic response by hyperpolarized 13C-fumarate MRS and diffusion MRI

Targeted chemotherapeutic agents often do not result in tumor shrinkage, so new biomarkers that correlate with clinical efficacy are needed. In this study, we investigated noninvasive imaging protocols to monitor responses to sorafenib, a multikinase inhibitor approved for treatment of renal cell and hepatocellular carcinoma. Healthy cells are impermeable to fumarate, so conversion of this metabolite to malate as detected by (13)C-magnetic resonance spectroscopy (MRS) has been suggested as one marker for cell death and treatment response in tumors. Diffusion MRI also has been suggested as a measure of therapy-induced cytotoxic edema because viable cells act as a diffusion barrier in tissue. For these reasons, we assessed sorafenib responses using hyperpolarized (13)C-fumarate, diffusion-weighted MRI (DW-MRI) in a xenograft model of human breast cancer in which daily administration of sorafenib was sufficient to stabilize tumor growth. We detected signals from fumarate and malate following intravenous administration of hyperpolarized fumarate with a progressive increase in the malate-to-fumarate (MA/FA) ratio at days 2 to 5 after sorafenib infusion. The apparent diffusion coefficient (ADC) measured by DW-MRI increased in the treated group consistent with cytotoxic edema. However, the MA/FA ratio was a more sensitive marker of therapeutic response than ADC, with 2.8-fold versus 1.3-fold changes, respectively, by day 5 of drug treatment. Histologic analyses confirmed cell death in the sorafenib-treated cohort. Notably, (13)C-pyruvate-to-lactate conversion was not affected by sorafenib in the breast cancer model examined. Our results illustrate how combining hyperpolarized substrates with DW-MRI can allow noninvasive monitoring of targeted therapeutic responses at relatively early times after drug administration.

Expression of drug targets in patients treated with sorafenib, carboplatin and paclitaxel

Introduction

Sorafenib, a multitarget kinase inhibitor, targets members of the mitogen-activated protein kinase (MAPK) pathway and VEGFR kinases. Here we assessed the association between expression of sorafenib targets and biomarkers of taxane sensitivity and response to therapy in pre-treatment tumors from patients enrolled in ECOG 2603, a phase III comparing sorafenib, carboplatin and paclitaxel (SCP) to carboplatin, paclitaxel and placebo (CP).

Methods

Using a method of automated quantitative analysis (AQUA) of in situ protein expression, we quantified expression of VEGF-R2, VEGF-R1, VEGF-R3, FGF-R1, PDGF-Rβ, c-Kit, B-Raf, C-Raf, MEK1, ERK1/2, STMN1, MAP2, EB1 and Bcl-2 in pretreatment specimens from 263 patients.

Results

An association was found between high FGF-R1 and VEGF-R1 and increased progression-free survival (PFS) and overall survival (OS) in our combined cohort (SCP and CP arms). Expression of FGF-R1 and VEGF-R1 was higher in patients who responded to therapy ((CR+PR) vs. (SD+PD+ un-evaluable)).

Conclusions

In light of the absence of treatment effect associated with sorafenib, the association found between FGF-R1 and VEGF-R1 expression and OS, PFS and response might reflect a predictive biomarker signature for carboplatin/paclitaxel-based therapy. Seeing that carboplatin and pacitaxel are now widely used for this disease, corroboration in another cohort might enable us to improve the therapeutic ratio of this regimen.

A phase II study of gemcitabine and cisplatin plus sorafenib in patients with advanced biliary adenocarcinomas

Background:

This study evaluated the addition of sorafenib to gemcitabine and cisplatin in biliary adenocarcinoma first-line therapy.

Methods:

Patients with advanced biliary adenocarcinomas received gemcitabine 1000 mg m⁻² and cisplatin 25 mg m⁻² on a 2 weeks on/1 week off cycle and sorafenib 400 mg twice daily. After the initial 16 patients were enrolled, the chemotherapy doses were amended in view of grade 3 and 4 hand–foot skin reaction and haematologic toxicity. Subsequently, 21 patients received gemcitabine 800 mg m⁻², cisplatin 20 mg m⁻² and sorafenib 400 mg. The primary end point was an improvement in 6-month progression-free survival (PFS6) from historical 57–77% (90% power, type I error of 10%). Pretreatment pERK, evaluated by immunostaining, was correlated with clinical outcome.

Results:

A total of 39 patients were accrued. The most common grade 3–4 toxicities noted in >10% of patients were fatigue, elevated liver function tests and haematologic toxicities including thromboemboli, hyponatraemia and hypophosphataemia. Six-month progression-free survival was 51% (95% confidence interval (CI) 34–66%). Median PFS and overall survival were 6.5 (95% CI: 3.5–8.3) and 14.4 months (95% CI: 11.6–19.2 months), respectively. No correlation was observed between pERK and outcomes.

Conclusion:

The addition of sorafenib to gemcitabine and cisplatin in biliary adenocarcinomas did not improve efficacy over historical data, and toxicity was increased.

Evolving pharmacotherapies for the treatment of metastatic melanoma

Metastatic melanoma remains a difficult disease to treat, and long term survivors are rare. Over the past few years, however, breakthroughs in both immunotherapy as well as targeted agents have had a tremendous impact on patients diagnosed with this disease. This review summarizes recent advances in systemic therapies for melanoma, including immune modulators directed against cytotoxic T lymphocyte associated antigen-4 (CTLA-4) and programmed death-1 (PD-1), as well as a number of targeted agents. These approaches hold great promise as the landscape of therapeutic options for advanced melanoma continues to evolve.

Phase I clinical trial of lenalidomide in combination with sorafenib in patients with advanced cancer

BACKGROUND

Preclinical data have shown that lenalidomide and sorafenib target endothelial cells, inhibiting growth of ocular melanoma cells in a xenograft model. We conducted a Phase I study of lenalidomide and sorafenib in patients with advanced cancer.

METHODS

During the escalation phase, lenalidomide (days 1-21) and sorafenib (days 1-28) were given orally once daily at the following respective doses: level 1 (10 mg, 200 mg); level 2 (10 mg, 400 mg); level 3 (20 mg, 400 mg); and level 4 (25 mg, 400 mg) (1 cycle = 28 days). A "3 + 3" study design was used.

RESULTS

Forty-one patients were treated (median age: 50 years). The most common diagnoses were adenoid cystic carcinoma (N = 9), ovarian adenocarcinoma (N = 7), and melanoma (N = 6); 142 cycles (median: 3) were administered. No dose-limiting toxicities were noted. The maximum tested dose (dose level 4) was used in the expansion phase. Grade 3-4 treatment-related toxicities were neutropenia, thrombocytopenia, skin rash, and thromboembolism. Of 38 patients who were evaluable for response, stable disease (SD) was noted in 53 % of patients (SD ≥6 months: 16 %). Tumor types with SD ≥ 6 months were as follows: ocular melanoma, 2/2 (100 %); other melanoma, 1/4 (25 %); adenoid cystic carcinoma, 2/9 (22 %); and ovarian cancer, 1/6 (17 %). The median progression-free survival duration was 3.5 months (95 % CI, 1.9-5.0), and the median overall survival duration was 12.3 months (95 % CI, 10.1-14.5).

CONCLUSIONS

Lenalidomide and sorafenib was well tolerated and associated with disease stabilization for ≥6 months in patients with melanoma, adenoid cystic carcinoma, and ovarian adenocarcinoma.

Update on the targeted therapy of melanoma

Melanoma is the most aggressive of the cutaneous malignancies, causing more than 9,000 deaths in the past year in the United States. Historically, systemic therapies have been largely ineffective, because melanoma is usually resistant to cytotoxic chemotherapy. However, during the past few years, several targeted therapies have proved effective in this challenging disease. These recent advances have been facilitated by an improved understanding of the driving genetic aberrations of melanoma, particularly mutations in the mitogen-activated protein kinase (MAPK) pathway. Vemurafenib, a BRAF inhibitor, demonstrated an overall survival advantage in phase III trials and is an appropriate option for first-line therapy in metastatic BRAF mutant melanoma. Dabrafenib, another BRAF inhibitor, and trametinib, a MEK inhibitor, also have been shown to be effective in phase III trials for BRAF mutant melanoma and may be additional treatment options as monotherapy or in combination pending regulatory approval. Additionally, imatinib is a promising targeted therapy for patients whose tumors harbor a KIT mutation in exons 11 and 13. Although these targeted agents cause objective responses and clinical benefit in patients with metastatic melanoma, resistance invariably develops. New targets and strategies to overcome acquired resistance are urgently needed. Furthermore, no effective targeted therapy has been developed for NRAS mutant tumors or in melanomas with as yet unknown driver mutations. In this review, we discuss current molecular targeted treatment options and promising ongoing research to develop new strategies to treat melanoma.

Advances in personalized targeted treatment of metastatic melanoma and non-invasive tumor monitoring

Despite extensive scientific progress in the melanoma field, treatment of advanced stage melanoma with chemotherapeutics and biotherapeutics has rarely provided response rates higher than 20%. In the past decade, targeted inhibitors have been developed for metastatic melanoma, leading to the advent of more personalized therapies of genetically characterized tumors. Here we review current melanoma treatments and emerging targeted molecular therapies. In particular we discuss the mutant BRAF inhibitors Vemurafenib and Dabrafenib, which markedly inhibit tumor growth and advance patients' overall survival. However this response is almost inevitably followed by complete tumor relapse due to drug resistance hampering the encouraging initial responses. Several mechanisms of resistance within and outside the MAPK pathway have now been uncovered and have paved the way for clinical trials of combination therapies to try and overcome tumor relapse. It is apparent that personalized treatment management will be required in this new era of targeted treatment. Circulating tumor cells (CTCs) provide an easily accessible means of monitoring patient relapse and several new approaches are available for the molecular characterization of CTCs. Thus CTCs provide a monitoring tool to evaluate treatment efficacy and early detection of drug resistance in real time. We detail here how advances in the molecular analysis of CTCs may provide insight into new avenues of approaching therapeutic options that would benefit personalized melanoma management.

Genetics of melanoma

Genomic variation is a trend observed in various human diseases including cancer. Genetic studies have set out to understand how and why these variations result in cancer, why some populations are pre-disposed to the disease, and also how genetics affect drug responses. The melanoma incidence has been increasing at an alarming rate worldwide. The burden posed by melanoma has made it a necessity to understand the fundamental signaling pathways involved in this deadly disease. Signaling cascades such as mitogen-activated protein kinase and PI3K/AKT have been shown to be crucial in the regulation of processes that are commonly dysregulated during cancer development such as aberrant proliferation, loss of cell cycle control, impaired apoptosis, and altered drug metabolism. Understanding how these and other oncogenic pathways are regulated has been integral in our challenge to develop potent anti-melanoma drugs. With advances in technology and especially in next generation sequencing, we have been able to explore melanoma genomes and exomes leading to the identification of previously unknown genes with functions in melanomagenesis such as GRIN2A and PREX2. The therapeutic potential of these novel candidate genes is actively being pursued with some presenting as druggable targets while others serve as indicators of therapeutic responses. In addition, the analysis of the mutational signatures of melanoma tumors continues to cement the causative role of UV exposure in melanoma pathogenesis. It has become distinctly clear that melanomas from sun-exposed skin areas have distinct mutational signatures including C to T transitions indicative of UV-induced damage. It is thus necessary to continue spreading awareness on how to decrease the risk factors of developing the disease while at the same time working for a cure. Given the large amount of information gained from these sequencing studies, it is likely that in the future, treatment of melanoma will follow a highly personalized route that takes into account the differential mutational signatures of each individual’s cancer.