Dabrafenib and trametinib versus dabrafenib and placebo for Val600 BRAF-mutant melanoma: a multicentre, double-blind, phase 3 randomised controlled trial

(Neo)adjuvant systemic therapy for melanoma

Surgery still is the cornerstone of treatment for patients with stage II and III melanoma, but despite great efforts to gain or preserve locoregional control with excision of the primary tumour, satellites, intransits, sentinel node biopsy and lymphadenectomy, surgery alone does not seem to improve survival any further. Prognosis for patients with high risk melanoma remains poor with 5-year survival rates of 40 to 80%. Only interferon-2b has been approved as adjuvant therapy since 1995, but clinical integration is low considering the high risk-benefit ratio. In recent years systemic targeted- and immunotherapy have proven to be beneficial in advanced melanoma and could be a promising strategy for (neo)adjuvant treatment of patients with resectable high risk melanomas as well. Randomised, placebo- controlled phase III trials on adjuvant systemic targeted- and immunotherapy are currently being performed using new agents like ipilimumab, pembrolizumab, nivolumab, vemurafenib and dabrafenib plus trametinib. In this article we review the literature on currently known adjuvant therapies and currently ongoing trials of (neo)adjuvant therapies in high risk melanomas.

Multiple roles of NF1 in the melanocyte lineage

NF1 is a tumour suppressor gene, germline mutations of which lead to neurofibromatosis type 1 syndrome. Patients develop benign tumours from several types of cells including neural crest-derived cells. NF1 somatic mutations also occur in 15% of sporadic melanoma, a cancer originating from melanocytes. Evidence now suggests the involvement of NF1 mutations in melanoma resistance to targeted therapies. Although NF1 is ubiquitously expressed, genetic links between NF1 and genes involved in melanocyte biology have been described, implying the lineage-specific mechanisms. In this review, we summarize and discuss the latest advances related to the roles of NF1 in melanocyte biology and in cutaneous melanoma.

Dabrafenib plus trametinib in patients with previously treated BRAF(V600E)-mutant metastatic non-small cell lung cancer: an open-label, multicentre phase 2 trial

BACKGROUND

BRAF mutations act as an oncogenic driver via the mitogen-activated protein kinase (MAPK) pathway in non-small cell lung cancer (NSCLC). BRAF inhibition has shown antitumour activity in patients with BRAF(V600E)-mutant NSCLC. Dual MAPK pathway inhibition with BRAF and MEK inhibitors in BRAF(V600E)-mutant NSCLC might improve efficacy over BRAF inhibitor monotherapy based on observations in BRAF(V600)-mutant melanoma. We aimed to assess the antitumour activity and safety of dabrafenib plus trametinib in patients with BRAF(V600E)-mutant NSCLC.

METHODS

In this phase 2, multicentre, non-randomised, open-label study, we enrolled adult patients (aged ≥18 years) with pretreated metastatic stage IV BRAF(V600E)-mutant NSCLC who had documented tumour progression after at least one previous platinum-based chemotherapy and had had no more than three previous systemic anticancer therapies. Patients with previous BRAF or MEK inhibitor treatment were ineligible. Patients with brain metastases were allowed to enrol only if the lesions were asymptomatic, untreated (or stable more than 3 weeks after local therapy if treated), and measured less than 1 cm. Enrolled patients received oral dabrafenib (150 mg twice daily) plus oral trametinib (2 mg once daily) in continuous 21-day cycles until disease progression, unacceptable adverse events, withdrawal of consent, or death. The primary endpoint was investigator-assessed overall response, which was assessed by intention to treat in the protocol-defined population (patients who received second-line or later treatment); safety was also assessed in this population and was assessed at least once every 3 weeks, with adverse events, laboratory values, and vital signs graded according to the Common Terminology Criteria for Adverse Events version 4.0. The study is ongoing but no longer recruiting patients. This trial is registered with ClinicalTrials.gov, number NCT01336634.

FINDINGS

Between Dec 20, 2013, and Jan 14, 2015, 59 patients from 30 centres in nine countries across North America, Europe, and Asia met eligibility criteria. Two patients who had previously been untreated due to protocol deviation were excluded; thus, 57 eligible patients were enrolled. 36 patients (63·2% [95% CI 49·3-75·6]) achieved an investigator-assessed overall response. Serious adverse events were reported in 32 (56%) of 57 patients and included pyrexia in nine (16%), anaemia in three (5%), confusional state in two (4%), decreased appetite in two (4%), haemoptysis in two (4%), hypercalcaemia in two (4%), nausea in two (4%), and cutaneous squamous cell carcinoma in two (4%). The most common grade 3-4 adverse events were neutropenia in five patients (9%), hyponatraemia in four (7%), and anaemia in three (5%). Four patients died during the study from fatal adverse events judged to be unrelated to treatment (one retroperitoneal haemorrhage, one subarachnoid haemorrhage, one respiratory distress, and one from disease progression that was more severe than typical progression, as assessed by the investigator).

INTERPRETATION

Dabrafenib plus trametinib could represent a new targeted therapy with robust antitumour activity and a manageable safety profile in patients with BRAF(V600E)-mutant NSCLC.

FUNDING

GlaxoSmithKline.

Acquired Resistance to Clinical Cancer Therapy: A Twist in Physiological Signaling

Although modern therapeutic strategies have brought significant progress to cancer care in the last 30 years, drug resistance to targeted monotherapies has emerged as a major challenge. Aberrant regulation of multiple physiological signaling pathways indispensable for developmental and metabolic homeostasis, such as hyperactivation of pro-survival signaling axes, loss of suppressive regulations, and impaired functionalities of the immune system, have been extensively investigated aiming to understand the diversity of molecular mechanisms that underlie cancer development and progression. In this review, we intend to discuss the molecular mechanisms of how conventional physiological signal transduction confers to acquired drug resistance in cancer patients. We will particularly focus on protooncogenic receptor kinase inhibition-elicited tumor cell adaptation through two major core downstream signaling cascades, the PI3K/Akt and MAPK pathways. These pathways are crucial for cell growth and differentiation and are frequently hyperactivated during tumorigenesis. In addition, we also emphasize the emerging roles of the deregulated host immune system that may actively promote cancer progression and attenuate immunosurveillance in cancer therapies. Understanding these mechanisms may help to develop more effective therapeutic strategies that are able to keep the tumor in check and even possibly turn cancer into a chronic disease.

Targeting the PI3K/AKT/mTOR pathway overcomes the stimulating effect of dabrafenib on the invasive behavior of melanoma cells with acquired resistance to the BRAF inhibitor

BRAF inhibitors (BRAFi) have proven clinical benefits in patients with BRAF-mutant melanoma. However, acquired resistance eventually arises. The effects of BRAFi on melanoma cell proliferation and survival have been extensively studied, and several mechanisms involved in acquired resistance to the growth suppressive activity of these drugs have been identified. Much less is known about the impact of BRAFi, and in particular of dabrafenib, on the invasive potential of melanoma cells. In the present study, the BRAF-mutant human melanoma cell line A375 and its dabrafenib-resistant subline A375R were analyzed for invasive capacity, expression of vascular endothelial growth factor receptor (VEGFR)-2, and secretion of VEGF-A and matrix metalloproteinase (MMP)-9, under basal conditions or in response to dabrafenib. The consequences of inhibiting the PI3K/AKT/mTOR pathway on A375R cell responses to dabrafenib were also evaluated. We found that A375R cells were more invasive and secreted higher levels of VEGF-A and MMP-9 as compared with A375 cells. Dabrafenib reduced invasiveness, VEGFR-2 expression and VEGF-A secretion in A375 cells, whereas it increased invasiveness, VEGF-A and MMP-9 release in A375R cells. In these latter cells, the stimulating effects of dabrafenib on the invasive capacity were markedly impaired by the anti-VEGF‑A antibody bevacizumab, or by AKT1 silencing. A375R cells were not cross-resistant to the PI3K/mTOR inhibitor GSK2126458A. Moreover, this inhibitor given in combination with dabrafenib efficiently counteracted the stimulating effects of the BRAFi on invasiveness and VEGF-A and MMP-9 secretion. Our data demonstrate that melanoma cells with acquired resistance to dabrafenib possess a more invasive phenotype which is further stimulated by exposure to the drug. Substantial evidence indicates that continuing BRAFi therapy beyond progression produces a clinical benefit. Our results suggest that after the development of resistance, a regimen combining BRAFi with bevacizumab or with inhibitors of the PI3K/AKT/mTOR pathway might be more effective than BRAFi monotherapy.

Pembrolizumab for the treatment of advanced melanoma

INTRODUCTION

Since 2010 multiple targeted therapies and immunotherapies have been approved for the treatment of advanced melanoma. Pembrolizumab, a humanized monoclonal antibody directed against programed death receptor 1 has shown significant activity in advanced melanoma resulting in its approval first as post-ipilimumab and subsequently as frontline treatment.

AREAS COVERED

This article reviews the approved agents for the treatment of advanced melanoma with a focus on the preclinical and clinical evidence for the use of pembrolizumab in this setting. Primary emphasis is given to the clinical development of pembrolizumab, including phase I-III trials. Finally, we explore the role of pembrolizumab in combination with other therapies and ongoing investigations into its effectiveness in expanded patient populations.

EXPERT OPINION

Pembrolizumab provides durable responses and represents a major advancement in the treatment options for patients with advanced melanoma. Early studies of pembrolizumab in combination with other therapeutic agents have generated significant interest and further investigations including advanced clinical trials are warranted to evaluate safety and potential improved outcomes. Pembrolizumab and other immune checkpoint inhibitors are likely to play an expanded role in the treatment of advanced melanoma and other solid tumors over the next decade.

Are there, or shall we discover, biomarkers to guide PD-1 inhibition?

Paolo A Ascierto and Ramon A de Mello speak to Ellen Clarke, Commissioning Editor Despite the recent success of PD-1/PD-L1-directed immunotherapy in a number of different malignancies, there are currently no effective biomarkers available to predict patient response to treatment. This question is particularly important because these immunotherapy agents are expensive and have significant toxicity profiles. Early data are emerging on biomarkers such as PD-L1 expression; however, it is clear that further studies are needed to identify alternative biomarkers and to improve understanding of the host immune system and tumor microenvironment. In a panel interview Paolo Ascierto and Ramon de Mello discuss this important clinical question.

The influence of subclonal resistance mutations on targeted cancer therapy

Clinical oncology is being revolutionized by the increasing use of molecularly targeted therapies. This paradigm holds great promise for improving cancer treatment; however, allocating specific therapies to the patients who are most likely to derive a durable benefit continues to represent a considerable challenge. Evidence continues to emerge that cancers are characterized by extensive intratumour genetic heterogeneity, and that patients being considered for treatment with a targeted agent might, therefore, already possess resistance to the drug in a minority of cells. Indeed, multiple examples of pre-existing subclonal resistance mutations to various molecularly targeted agents have been described, which we review herein. Early detection of pre-existing or emerging drug resistance could enable more personalized use of targeted cancer therapy, as patients could be stratified to receive the therapies that are most likely to be effective. We consider how monitoring of drug resistance could be incorporated into clinical practice to optimize the use of targeted therapies in individual patients.

Paradoxical activation of MEK/ERK signaling induced by B-Raf inhibition enhances DR5 expression and DR5 activation-induced apoptosis in Ras-mutant cancer cells

B-Raf inhibitors have been used for the treatment of some B-Raf–mutated cancers. They effectively inhibit B-Raf/MEK/ERK signaling in cancers harboring mutant B-Raf, but paradoxically activates MEK/ERK in Ras-mutated cancers. Death receptor 5 (DR5), a cell surface pro-apoptotic protein, triggers apoptosis upon ligation with tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) or aggregation. This study focused on determining the effects of B-Raf inhibition on DR5 expression and DR5 activation-induced apoptosis in Ras-mutant cancer cells. Using chemical and genetic approaches, we have demonstrated that the B-Raf inhibitor PLX4032 induces DR5 upregulation exclusively in Ras-mutant cancer cells; this effect is dependent on Ras/c-Raf/MEK/ERK signaling activation. PLX4032 induces DR5 expression at transcriptional levels, largely due to enhancing CHOP/Elk1-mediated DR5 transcription. Pre-exposure of Ras-mutated cancer cells to PLX4032 sensitizes them to TRAIL-induced apoptosis; this is also a c-Raf/MEK/ERK-dependent event. Collectively, our findings highlight a previously undiscovered effect of B-Raf inhibition on the induction of DR5 expression and the enhancement of DR5 activation-induced apoptosis in Ras-mutant cancer cells and hence may suggest a novel therapeutic strategy against Ras-mutated cancer cells by driving their death due to DR5-dependent apoptosis through B-Raf inhibition.

Clinical outcome of treatment with serine-threonine kinase inhibitors in recurrent epithelial ovarian cancer: a systematic review of literature

INTRODUCTION

While serine-threonine kinases (STK) are attractive therapeutic targets in epithelial ovarian cancer, clinical outcomes of STK inhibitors in the management of recurrent disease have not been completely described.

AREAS COVERED

A systematic literature review of published clinical studies on STK inhibitors targeting mTOR, MAPK, and aurora kinase pathways in recurrent epithelial ovarian cancer was conducted, revealing 18 clinical trials (497 patients). Pooled analyses were performed to assess treatment response, survival time, and adverse events. Median progression-free survival was 3.4 months in STK inhibitor-based therapy, and the average response rate and clinical benefit rate were 13% and 67%, respectively. Among regimens comprised of only STK inhibitors (11 trials, 299 patients), median progression-free time was 2.7 months, response rate was 10%, and clinical benefit rate was 64%. Compared to single STK inhibitor monotherapy (52.5%), clinical benefit rates significantly improved when STK inhibitors were combined with a cytotoxic agent (71.4%), other class biological agent (74.2%), or an additional STK inhibitor (95.0%) (all, P ≤ 0.002).

EXPERT OPINION

STK inhibitor-based therapy showed modest activity for recurrent epithelial ovarian cancer with reasonable clinical benefit rates, suggesting its potential utility for maintaining disease stability if supported by future studies. Efficacy appears greatly improved in appropriately selected patient populations, especially those with low-grade serous ovarian carcinoma, platinum-sensitive disease, cancers with somatic RAS or BRAF mutations, and when used in a combination regimen with a cytotoxic or biological agent.

What Is New in Melanoma Genetics and Treatment?

New therapies for advanced melanoma have led to major advances, which, for the first time, showed improved survival for patients with this very challenging neoplasm. These new treatments are based on gene-targeted therapies or stimulation of immune responses. However, these treatments are not without challenges in terms of resistance and toxicity. Physicians should be aware of these side effects as prompt treatment may save lives. Melanoma genetics is also unravelling new genetic risk factors involving telomere genes as well as new gene pathways at the somatic level which may soon become therapeutic targets. It is also shedding new light onto the pathology of this tumour with links to neural diseases and longevity.

[Systemic treatment of inoperable metastasized malignant melanoma]

BACKGROUND

The medical therapy of inoperable malignant melanoma has changed dramatically over the last few years.

OBJECTIVES

The purpose of this article is to summarize the current state of systemic medical treatment of malignant melanoma.

MATERIALS AND METHODS

Clinical studies and guidelines in the therapy of malignant melanoma are reviewed.

RESULTS

Medical therapy of inoperable melanoma changed due to developments in immunotherapies (checkpoint inhibitors) and molecular-targeted therapies (BRAF and MEK inhibitors). Checkpoint inhibitors are antibodies administered as infusions every 2-3 weeks, blocking the checkpoints PD-1 or CTLA-4, thus, preventing downregulation of the immune system. BRAF and MEK inhibitors are small molecules, they are given orally and block a certain signaling pathway in tumor cells. The activation of this pathway has to be demonstrated by molecular analysis of tumor tissue first. This strategy is currently registered for 40-50 % of melanomas harboring a BRAF V600 mutation, while the combination of a BRAF plus MEK inhibitor has been proven more efficient than a BRAF inhibitor alone.

DISCUSSION

A fascinating development has started in the melanoma field due to immunotherapeutic and molecular-targeted treatment strategies. The continuation of this development needs further clinical and translational studies. This includes particular clinical studies with the new substances in the adjuvant situation, and sequences and combinations in the metastatic setting. Translational studies are needed to develop biomarkers for response and side effects.

Improving patient outcomes to targeted therapies in melanoma

INTRODUCTION

The arrival of targeted therapies has led to significant improvements in clinical outcomes for patients with BRAFV600 mutated advanced melanoma over the past five years.

AREAS COVERED

In several clinical trials, BRAF and MEK inhibitors have shown improvement in progression free and overall survival, along with much higher tumor response rates in comparison to chemotherapy, with the combination of these drugs superior to monotherapy. These agents are also being tested in earlier-stage patients, in addition to alternative dosing regimens and in combinations with other therapeutics. Efforts are also ongoing to expand the success found with targeted therapies to other subtypes of melanoma, including NRAS and c-kit mutated melanomas, uveal melanomas, and BRAF/NRAS wild type melanomas. Expert Commentary: We aim to provide an overview of clinical outcomes with targeted therapies in melanoma patients.

BET and BRAF inhibitors act synergistically against BRAF-mutant melanoma

Despite major advances in the treatment of metastatic melanoma, treatment failure is still inevitable in most cases. Manipulation of key epigenetic regulators, including inhibition of Bromodomain and extra‐terminal domain (BET) family members impairs cell proliferation in vitro and tumor growth in vivo in different cancers, including melanoma. Here, we investigated the effect of combining the BET inhibitor JQ1 with the BRAF inhibitor Vemurafenib in in vitro and in vivo models of BRAF‐mutant melanoma. We performed cytotoxicity and apoptosis assays, and a xenograft mouse model to determine the in vitro and in vivo efficacy of JQ1 in combination with Vemurafenib against BRAF‐mutant melanoma cell lines. Further, to investigate the molecular mechanisms underlying the effects of combined treatment, we conducted antibody arrays of in vitro drug‐treated cell lines and RNA sequencing of drug‐treated xenograft tumors. The combination of JQ1 and Vemurafenib acted synergistically in BRAF‐mutant cell lines, resulting in marked apoptosis in vitro, with upregulation of proapoptotic proteins. In vivo, combination treatment suppressed tumor growth and significantly improved survival compared to either drug alone. RNA sequencing of tumor tissues revealed almost four thousand genes that were uniquely modulated by the combination, with several anti‐apoptotic genes significantly down‐regulated. Collectively, our data provide a rationale for combined BET and BRAF inhibition as a novel strategy for the treatment of melanoma.

Dabrafenib: a new opportunity for the treatment of BRAF V600-positive melanoma

Prior to 2011, the 1-year survival rates for patients suffering from advanced or metastatic melanoma was as low as 33%, with a median overall survival of about 9 months. Several chemotherapeutic regimens have been applied, either as monochemotherapy or as polychemotherapy, overall not resulting in an improvement of progression-free or overall survival. Novel insights into the epidemiology and biology of melanoma allowed the development of newer therapies. The discovery of mutations in BRAF, a part of the mitogen-activated protein kinase, allowed the development of two BRAF inhibitors, vemurafenib and dabrafenib, which significantly improved the outcome of metastatic melanoma treatment. This article reviews the mechanism of action, efficacy, and safety profile of dabrafenib. An in-depth knowledge of this medication will encourage clinicians to select the appropriate therapeutic strategy for each patient, as well as to prevent or adequately manage side effects, optimizing, thus, the drug's applicability.

Harnessing the immune system for the treatment of melanoma: current status and future prospects

When malignant melanoma is diagnosed early, surgical resection is the intervention of choice and is often curative, but many patients present with unresectable disease at later stages. Due to its complex etiology paired with well-documented chemoresistance and high metastatic potential, patients with advanced melanoma had a poor prognosis, and the treatment of this disease remained unsatisfactory for many years. Recently, targeted therapy, immune checkpoint inhibition, or combinatory approaches have revolutionized the therapeutic options of melanoma allowing considerable improvement in disease control and survival. In this review we will summarize these novel therapeutic strategies with particular focus on combinatory immunotherapies and further discuss recent data derived from immunogenomic studies and potential options to improve the therapeutic efficacy of immune modulatory approaches.

BRAF-Directed Therapy in Metastatic Colorectal Cancer

Activating BRAF (V-raf murine sarcoma viral oncogene homolog B) mutations occur in approximately 5% to 10% of patients with metastatic colorectal cancer, mostly V600E mutation, and it is associated with distinct clinical and pathological features. To date, there are no approved treatments to target this mutation. BRAF inhibitor monotherapy has limited efficacy, in contrast to metastatic melanoma. Combination strategies that block not only BRAF mutated kinase but other alternative pathways are ongoing and have demonstrated improved activity. This review aims to provide data about new strategies to target to BRAF gene mutation in metastatic colorectal cancer.

Managing leptomeningeal melanoma metastases in the era of immune and targeted therapy

Melanoma frequently metastasizes to the brain, with CNS involvement being clinically evident in ∼30% of patients (as high as 75% at autopsy). In ∼5% cases melanoma cells also metastasize to the leptomeninges, the sub-arachnoid space and cerebrospinal fluid (CSF). Patients with leptomeningeal melanoma metastases (LMM) have the worst prognosis and are characterized by rapid disease progression (mean survival 8-10 weeks) and a death from neurological causes. The recent years have seen tremendous progress in the development of targeted and immune therapies for melanoma that has translated into an increased survival benefit. Despite these gains, the majority of patients fail therapy and there is a suspicion that the brain and the leptomeninges are a "sanctuary" sites for melanoma cells that escape both targeted therapy and immunologic therapies. Emerging evidence suggests that (1) Cancer cells migrating to the CNS may have unique molecular properties and (2) the CNS/leptomeningeal microenvironment represents a pro-survival niche that influences therapeutic response. In this Mini-Review, we will outline the clinical course of LMM development and will describe how the intracranial immune and cellular microenvironments offer both opportunities and challenges for the successful management of this disease. We will further discuss the latest data demonstrating the potential use of BRAF inhibitors and immune therapy in the management of LMM, and will review future potential therapeutic strategies for the management of this most devastating complication of advanced melanoma.

The Complexity of the ERK/MAP-Kinase Pathway and the Treatment of Melanoma Skin Cancer

The central role played by the ERK/MAPK pathway downstream of RAS in human neoplasias is best exemplified in the context of melanoma skin cancer. Signaling through the MAPK pathway is crucial for the proliferation of melanocytes, the healthy pigment cells that give rise to melanoma. However, hyper-activation of the MAPK-pathway is found in over 90% of melanomas with approximately 50% of all patients displaying mutations in the kinase BRAF, and approximately 28% of all patients harboring mutations in the MAPK-pathway up-stream regulator NRAS. This finding has led to the development of BRAF and MEK inhibitors whose application in the clinic has shown unprecedented survival responses. Unfortunately the responses to MAPK pathway inhibitors are transient with most patients progressing within a year and a median progression free survival of 7-10 months. The disease progression is due to the development of drug-resistance based on various mechanisms, many of them involving a rewiring of the MAPK pathway. In this article we will review the complexity of MAPK signaling in melanocytic cells as well as the mechanisms of action of different MAPK-pathway inhibitors and their correlation with clinical response. We will reflect on mechanisms of innate and acquired resistance that limit patient's response, with a focus on the MAPK signaling network. Because of the resurgence of antibody-based immune-therapies there is a growing feeling of failure in the targeted therapy camp. However, recent studies have revealed new windows of therapeutic opportunity for melanoma sufferers treated with drugs targeting the MAPK pathway, and these opportunities will be discussed.

Quantitative assessment of BRAF V600 mutant circulating cell-free tumor DNA as a tool for therapeutic monitoring in metastatic melanoma patients treated with BRAF/MEK inhibitors

BACKGROUND

BRAF V600 mutant circulating cell-free tumor DNA (BRAF V600mut ctDNA) could serve as a specific biomarker in patients with BRAF V600 mutant melanoma. We analyzed the value of BRAF V600mut ctDNA from plasma as a monitoring tool for advanced melanoma patients treated with BRAF/MEK inhibitors.

METHODS

Allele-specific quantitative PCR analysis for BRAF V600 E/E2/D/K/R/M mutations was performed on DNA extracted from plasma of patients with known BRAF V600 mutant melanoma who were treated with dabrafenib and trametinib.

RESULTS

245 plasma samples from 36 patients were analyzed. In 16 patients the first plasma sample was obtained before the first dosing of dabrafenib/trametinib. At baseline, BRAF V600mut ctDNA was detected in 75 % of patients (n = 12/16). BRAF V600mut ctDNA decreased rapidly upon initiation of targeted therapy (p < 0.001) and became undetectable in 60 % of patients (n = 7/12) after 6 weeks of treatment. During treatment, disease progression (PD) was diagnosed in 27 of 36 patients. An increase of the BRAF V600mut ctDNA copy number and fraction, identified PD with a sensitivity of 70 % (n = 19/27) and a specificity of 100 %. An increase in the BRAF V600mut ctDNA fraction was detected prior to clinical PD in 44 % of cases (n = 12/27) and simultaneously with PD in 26 % of patients (n = 7/27).

CONCLUSIONS

Quantitative analysis of BRAF V600mut ctDNA in plasma has unique features as a monitoring tool during treatment with BRAF/MEK inhibitors. Its potential as an early predictor of acquired resistance deserves further evaluation.

A phase I study of binimetinib (MEK162) in Japanese patients with advanced solid tumors

PURPOSE

Binimetinib is a potent, selective MEK1/2 inhibitor with demonstrated efficacy against BRAF- and RAS-mutant tumors. Retinal adverse events associated with MEK inhibitors have been reported in some cases. The aim of this study was to assess single-agent binimetinib, with detailed ophthalmologic monitoring, in Japanese patients with advanced solid tumors.

METHODS

This was an open-label phase I dose-escalation and dose-expansion study (NCT01469130). Adult patients with histologically confirmed, evaluable, advanced solid tumors were enrolled and treated with binimetinib 30 or 45 mg twice daily (BID). The primary objective was to determine the maximum tolerated dose (MTD) and/or recommended phase II dose (RP2D) of single-agent binimetinib in Japanese patients.

RESULTS

Twenty-one patients were enrolled; 3 and 8 patients had documented BRAF and KRAS mutations, respectively. Two of 6 patients (33 %) receiving binimetinib 45 mg BID in dose-escalation experienced recurrent grade 2 retinal adverse events (AEs) which were reversible, and this dose was declared the MTD and RP2D. All patients experienced ≥1 AE suspected to be treatment related; the most common (>50 %) were blood creatine phosphokinase increase (76 %), retinal detachment and aspartate aminotransferase increase (62 % each), and diarrhea (52 %). There were no complete or partial responses; 14 patients (67 %) had stable disease, which lasted >180 days in 5 patients. Expression of phospho-ERK decreased in the skin following binimetinib treatment at both dose levels, indicating target inhibition.

CONCLUSIONS

Binimetinib demonstrated efficacy and acceptable safety in Japanese patients with solid tumors, supporting the 45 mg BID dose of binimetinib as the RP2D.

BRAFV600E Mutations in High-Grade Colorectal Neuroendocrine Tumors May Predict Responsiveness to BRAF-MEK Combination Therapy

Neuroendocrine tumors comprise a heterogeneous group of malignancies with a broad spectrum of clinical behavior. Poorly differentiated tumors follow an aggressive course with limited treatment options, and new approaches are needed. Oncogenic BRAF V600E (BRAF(V600E)) substitutions are observed primarily in melanoma, colon cancer, and non-small cell lung cancer, but have been identified in multiple tumor types. Here, we describe the first reported recurrent BRAF(V600E) mutations in advanced high-grade colorectal neuroendocrine tumors and identify a BRAF alteration frequency of 9% in 108 cases. Among these BRAF alterations, 80% were BRAF(V600E) Dramatic response to BRAF-MEK combination therapy occurred in two cases of metastatic high-grade rectal neuroendocrine carcinoma refractory to standard therapy. Urinary BRAF(V600E) circulating tumor DNA monitoring paralleled disease response. Our series represents the largest study of genomic profiling in colorectal neuroendocrine tumors and provides strong evidence that BRAF(V600E) is an oncogenic driver responsive to BRAF-MEK combination therapy in this molecular subset.

SIGNIFICANCE

BRAF(V600E) is an established oncogenic driver, but significant disparities in response exist among tumor types. Two patients with treatment-refractory high-grade colorectal neuroendocrine tumors harboring BRAF(V600E) exhibited rapid and durable response to combined BRAF-MEK inhibition, providing the first clinical evidence of efficacy in this aggressive tumor type. Cancer Discov; 6(6); 594-600. ©2016 AACR.This article is highlighted in the In This Issue feature, p. 561.

Selumetinib for the treatment of metastatic uveal melanoma: past and future perspectives

Uveal melanoma is a rare but aggressive subtype of melanoma. Nearly 50% of patients will develop metastatic disease despite primary enucleation or radiation therapy. There is currently no standard of care therapy for metastatic uveal melanoma, and no therapy that has been shown to prolong overall survival. Uveal melanoma is characterized by activation of signaling pathways including the MAPK pathway and the PI3K/AKT pathway, among others, via mutations in the G-α-proteins GNAQ and GNA11. MEK inhibition with selumetinib has been evaluated as a therapeutic strategy in metastatic uveal melanoma. This review will discuss preclinical and clinical studies evaluating selumetinib in metastatic uveal melanoma, as well as potential future perspectives on MEK inhibition in the management of metastatic uveal melanoma.

Combination Therapies for Melanoma: A New Standard of Care?

Recent data have demonstrated improved survival with targeted and immune therapies in patients with advanced melanoma, leading to much excitement amongst the oncology community and the widespread use of these drugs in combination regimens. However, the place of these combination therapies in the treatment of advanced melanoma remains to be fully determined. In this perspectives article, we critically review the available data and outline the rationale for these combinations being adopted as the standard of care for patients with advanced melanoma in the future.

IL15 Agonists Overcome the Immunosuppressive Effects of MEK Inhibitors

Many signal transduction inhibitors are being developed for cancer therapy target pathways that are also important for the proper function of antitumor lymphocytes, possibly weakening their therapeutic effects. Here we show that most inhibitors targeting multiple signaling pathways have especially strong negative effects on T-cell activation at their active doses on cancer cells. In particular, we found that recently approved MEK inhibitors displayed potent suppressive effects on T cells in vitro However, these effects could be attenuated by certain cytokines that can be administered to cancer patients. Among them, clinically available IL15 superagonists, which can activate PI3K selectively in T lymphocytes, synergized with MEK inhibitors in vivo to elicit potent and durable antitumor responses, including by a vaccine-like effect that generated resistance to tumor rechallenge. Our work identifies a clinically actionable approach to overcome the T-cell-suppressive effects of MEK inhibitors and illustrates how to reconcile the deficiencies of signal transduction inhibitors, which impede desired immunologic effects in vivo Cancer Res; 76(9); 2561-72. ©2016 AACR.

Inhibiting Drivers of Non-mutational Drug Tolerance Is a Salvage Strategy for Targeted Melanoma Therapy

Once melanomas have progressed with acquired resistance to mitogen-activated protein kinase (MAPK)-targeted therapy, mutational heterogeneity presents a major challenge. We therefore examined the therapy phase before acquired resistance had developed and discovered the melanoma survival oncogene MITF as a driver of an early non-mutational and reversible drug-tolerance state, which is induced by PAX3-mediated upregulation of MITF. A drug-repositioning screen identified the HIV1-protease inhibitor nelfinavir as potent suppressor of PAX3 and MITF expression. Nelfinavir profoundly sensitizes BRAF and NRAS mutant melanoma cells to MAPK-pathway inhibitors. Moreover, nelfinavir is effective in BRAF and NRAS mutant melanoma cells isolated from patients progressed on MAPK inhibitor (MAPKi) therapy and in BRAF/NRAS/PTEN mutant tumors. We demonstrate that inhibiting a driver of MAPKi-induced drug tolerance could improve current approaches of targeted melanoma therapy.

[Updates on prevention and treatment of melanoma: Pharmacist involvements and challenges]

Melanoma is a skin cancer that represents an actual public health problem. Its incidence is increasing every year. Environmental risk factors have been clearly identified. Early diagnosis of a suspicious skin lesion should be possible by any health professionals because the prognosis is correlated with the evolution of the disease and the presence of metastases. The advent of new therapies in metastatic forms with the development of immunotherapies and kinases inhibitors has significantly changed the management of this disease. New therapies are available in retail pharmacies and involve health professionals out of the hospital. This article is intended for community and hospital pharmacists and summarizes recommendations for primary and secondary prevention. It updates on new targeted therapies. It wants to give advices to the community pharmacists about the effective use of those treatments for melanoma.

Cell Cycle Phase-Specific Drug Resistance as an Escape Mechanism of Melanoma Cells

The tumor microenvironment is characterized by cancer cell subpopulations with heterogeneous cell cycle profiles. For example, hypoxic tumor zones contain clusters of cancer cells that arrest in G1 phase. It is conceivable that neoplastic cells exhibit differential drug sensitivity based on their residence in specific cell cycle phases. In this study, we used two-dimensional and organotypic melanoma culture models in combination with fluorescent cell cycle indicators to investigate the effects of cell cycle phases on clinically used drugs. We demonstrate that G1-arrested melanoma cells, irrespective of the underlying cause mediating G1 arrest, are resistant to apoptosis induced by the proteasome inhibitor bortezomib or the alkylating agent temozolomide. In contrast, G1-arrested cells were more sensitive to mitogen-activated protein kinase pathway inhibitor-induced cell death. Of clinical relevance, pretreatment of melanoma cells with a mitogen-activated protein kinase pathway inhibitor, which induced G1 arrest, resulted in resistance to temozolomide or bortezomib. On the other hand, pretreatment with temozolomide, which induced G2 arrest, did not result in resistance to mitogen-activated protein kinase pathway inhibitors. In summary, we established a model to study the effects of the cell cycle on drug sensitivity. Cell cycle phase-specific drug resistance is an escape mechanism of melanoma cells that has implications on the choice and timing of drug combination therapies.

Survival of patients with metastatic melanoma and brain metastases in the era of MAP-kinase inhibitors and immunologic checkpoint blockade antibodies: A systematic review

BACKGROUND

The incidence of brain metastases (BM) in melanoma patients is common and associated with poor prognosis. MAP-kinase inhibitors and immunologic checkpoint blockade antibodies led to improved survival of metastatic melanoma patients; however, patients with BM are under-represented or excluded from the majority of clinical trials and the impact of new drugs on their survival is less clear. With the present systematic review, we aimed to analyze outcomes of patients with melanoma BM treated with the new drugs, both in the setting of phase I-II-III clinical trials and in the "real world".

METHODS

An electronic search was performed to identify studies reporting survival outcomes of patients with melanoma BM treated with MAP-kinase inhibitors and/or immunologic checkpoint blockade antibodies, regardless of study design.

RESULTS

Twenty-two studies were included for a total of 2153 patients. Median OS was 7.9 months in phase I-II-III trials and 7.7 months in "real world" studies. In clinical trials, median OS was 7.0 months for patients treated with immunotherapy and 7.9 months for patients treated with BRAF inhibitors. In "real world" studies, median OS was 4.3 months and 7.7 months for patients treated with immunotherapy and BRAF inhibitors, respectively. Evidence of clinical activity exists for both immunotherapy and MAP-kinase inhibitors.

CONCLUSIONS

MAP-kinase inhibitors and immunologic checkpoint blockade antibodies have clinical activity and may achieve improved OS in patients with metastatic melanoma and BM. These results support the inclusion of patients with BM in investigations of new agents and new treatment regimens for metastatic melanoma.

Targeting metabolic reprogramming as a potential therapeutic strategy in melanoma

Metabolic reprogramming is a recognized hallmark of cancer. In order to support continued proliferation and growth, tumor cells must metabolically adapt to balance their bioenergetic and biosynthetic needs. To achieve this, cancer cells switch from mitochondrial oxidative phosphorylation to predominantly rely on glycolysis, a process known as the "Warburg effect". The BRAF oncogene has recently emerged as a critical regulator of this process in melanoma, bringing to the fore the importance of metabolic reprogramming in the pathogenesis and treatment of metastatic melanoma. In this review, we summarize our current understanding of oncogenic reprogramming of metabolism in BRAF and NRAS mutant melanoma, and highlight emerging evidence supporting a metabolic basis for MAPK pathway inhibitor resistance and metabolic vulnerabilities that may be exploited to overcome this.

The proportion cured of patients diagnosed with Stage III-IV cutaneous malignant melanoma in Sweden 1990-2007: A population-based study

The survival in cutaneous malignant melanoma (CMM) is highly dependent on the stage of the disease. Stage III-IV CMM patients are at high risk of relapse with a heterogeneous outcome, but not all experience excess mortality due to their disease. This group is referred to as the cure proportion representing the proportion of patients who experience the same mortality rate as the general population. The aim of this study was to estimate the cure proportion of patients diagnosed with Stage III-IV CMM in Sweden. From the population-based Swedish Melanoma Register, we included 856 patients diagnosed with primary Stage III-IV CMM, 1990-2007, followed-up through 2013. We used flexible parametric cure models to estimate cure proportions and median survival times (MSTs) of uncured by sex, age, tumor site, ulceration status (in Stage III patients) and disease stage. The standardized (over sex, age and site) cure proportion was lower in Stage IV CMMs (0.15, 95% CI 0.09-0.22) than non-ulcerated Stage III CMMs (0.48, 95% CI 0.41-0.55) with a statistically significant difference of 0.33 (95% CI = 0.24-0.41). Ulcerated Stage III CMMs had a cure proportion of 0.27 (95% CI 0.21-0.32) with a statistically significant difference compared to non-ulcerated Stage III CMMs (difference 0.21; 95% CI = 0.13-0.30). The standardized MST of uncured was approximately 9-10 months longer for non-ulcerated versus ulcerated Stage III CMMs. We could demonstrate a significantly better outcome in patients diagnosed with non-ulcerated Stage III CMMs compared to ulcerated Stage III CMMs and Stage IV disease after adjusting for age, sex and tumor site.

A Novel RAF Kinase Inhibitor with DFG-Out-Binding Mode: High Efficacy in BRAF-Mutant Tumor Xenograft Models in the Absence of Normal Tissue Hyperproliferation

BI 882370 is a highly potent and selective RAF inhibitor that binds to the DFG-out (inactive) conformation of the BRAF kinase. The compound inhibited proliferation of human BRAF-mutant melanoma cells with 100× higher potency (1-10 nmol/L) than vemurafenib, whereas wild-type cells were not affected at 1,000 nmol/L. BI 882370 administered orally was efficacious in multiple mouse models of BRAF-mutant melanomas and colorectal carcinomas, and at 25 mg/kg twice daily showed superior efficacy compared with vemurafenib, dabrafenib, or trametinib (dosed to provide exposures reached in patients). To model drug resistance, A375 melanoma-bearing mice were initially treated with vemurafenib; all tumors responded with regression, but the majority subsequently resumed growth. Trametinib did not show any efficacy in this progressing population. BI 882370 induced tumor regression; however, resistance developed within 3 weeks. BI 882370 in combination with trametinib resulted in more pronounced regressions, and resistance was not observed during 5 weeks of second-line therapy. Importantly, mice treated with BI 882370 did not show any body weight loss or clinical signs of intolerability, and no pathologic changes were observed in several major organs investigated, including skin. Furthermore, a pilot study in rats (up to 60 mg/kg daily for 2 weeks) indicated lack of toxicity in terms of clinical chemistry, hematology, pathology, and toxicogenomics. Our results indicate the feasibility of developing novel compounds that provide an improved therapeutic window compared with first-generation BRAF inhibitors, resulting in more pronounced and long-lasting pathway suppression and thus improved efficacy.

Biology and treatment of BRAF mutant metastatic melanoma

BRAF inhibitors were among the first systemic therapies to show clinical benefit in metastatic melanoma. Here, we review the spectrum of BRAF mutations in melanoma, their role in oncogenesis, clinicopathological associations and response to treatment. The differing biology and clinical features of V600E- and V600K-mutated melanoma are outlined. The molecular changes associated with BRAF fusion genes and their response to targeted therapies, as well as the role of immunotherapy in treatment sequencing with targeted therapies are discussed.

Distinct clinical patterns and immune infiltrates are observed at time of progression on targeted therapy versus immune checkpoint blockade for melanoma

We have made major advances in the treatment of melanoma through the use of targeted therapy and immune checkpoint blockade; however, clinicians are posed with therapeutic dilemmas regarding timing and sequence of therapy. There is a growing appreciation of the impact of antitumor immune responses to these therapies, and we performed studies to test the hypothesis that clinical patterns and immune infiltrates differ at progression on these treatments. We observed rapid clinical progression kinetics in patients on targeted therapy compared to immune checkpoint blockade. To gain insight into possible immune mechanisms behind these differences, we performed deep immune profiling in tumors of patients on therapy. We demonstrated low CD8⁺ T-cell infiltrate on targeted therapy and high CD8⁺ T-cell infiltrate on immune checkpoint blockade at clinical progression. These data have important implications, and suggest that antitumor immune responses should be assessed when considering therapeutic options for patients with melanoma.

Combination immune checkpoint blockade with ipilimumab and nivolumab in the management of advanced melanoma

INTRODUCTION

The use of immune checkpoint inhibitors for the treatment of advanced melanoma has evolved beyond monotherapies such as ipilimumab and nivolumab to combination strategies involving both. This combination approach results in response rates around 60% and superior progression-free survival compared with ipilimumab monotherapy (median 11.5 versus 2.9 months).

AREAS COVERED

A comprehensive literature search was undertaken including search terms of 'ipilimumab and nivolumab' and 'combination immune checkpoint therapy'. Relevant information contained in abstracts and conference presentations was included. This article summarizes the mechanism of action, efficacy and safety of combination ipilimumab and nivolumab across Phase I, II and III clinical trials. It also describes the place of combination therapy in the current market of advanced melanoma treatment options.

EXPERT OPINION

Efficacy for the combination approach is seen across a wide array of subgroups and occurs regardless of BRAF mutation status. Counterbalancing the apparent advantages, combination ipilimumab with nivolumab is associated with a high rate (55%) of grade 3/4 adverse events leading to discontinuation in a third of those treated. Most of these are manageable and do not appear to compromise durability of response. Overall survival information is currently immature but appears promising.

The impact of sequencing on diagnosis and treatment of malignant melanoma

Melanoma is one of the clinically most important cancer types considering its high mortality rate and that it is commonly diagnosed in relatively young people. With the advent of targeted therapies and, more recently, immune checkpoint inhibitors, more treatment options are available resulting in higher patient survival rates. However, the successful application of these targeted therapies critically depends on the reliable detection of molecular aberrations. Today, massively parallel sequencing techniques enable us to analyze large sets of genes in a relatively short time. It has allowed increased knowledge of acquired somatic mutations in melanoma and has helped to identify new targets for personalized therapy, and potentially may help to predict response to immune therapies. Described here are the development of sequencing techniques, how their improvement has changed diagnosis, prognosis and management of malignant melanoma and the future perspectives of melanoma diagnostics in the routine clinical setting.

[What's new in oncodermatology in 2015?]

Oncodermatology is the topic of constant innovation since 5 years. These innovations have drammatically modified the prognostic of skin cancers and induced a change in the paradigm that drives the whole oncology. Once again in 2015, melanoma is the key topic of scientific communication, with promising results. However, unmet clinical needs must be kept in light. Some diseases, such as squamous cell carcinoma or cutaneous lymphoma remain poorly evaluated. This article was designed as a review of litterature. All keywords of oncodermatology were searched in the main journals of dermatology, oncology and internal medicine. Despite methodologic restrictions, the number of articles imposed a choice based on opinion. The final goal was to transmit author's enthousiasm and the most important results.

Serum lactate dehydrogenase as an early marker for outcome in patients treated with anti-PD-1 therapy in metastatic melanoma

Background:

Treatment with programmed death receptor-1 (PD-1) antibodies is associated with high response rates in patients with advanced melanoma. Reliable markers for early response and outcome are still sparse.

Methods:

We evaluated 66 consecutive patients with advanced/metastatic melanoma treated with nivolumab or pembrolizumab between 2013 and 2014. The main objectives of this study were to investigate whether, first, serum lactate dehydrogenase (LDH) at baseline (normal vs above the upper limit of normal) correlates with overall survival (OS), and, second, whether the change of LDH during treatment predicts response before the first scan and OS in patients with an elevated baseline LDH.

Results:

After a median follow-up of 9 months, patients with an elevated baseline LDH (N=34) had a significantly shorter OS compared with patients with normal LDH (N=32; 6-month OS: 60.8% vs 81.6% and 12-month OS: 44.2% vs 71.5% (log-rank P=0.0292). In those 34 patients with elevated baseline LDH, the relative change during treatment was significantly associated with an objective response on the first scan: the 11 (32%) patients with partial remission had a mean reduction of −27.3% from elevated baseline LDH. In contrast, patients with progressive disease (N=15) had a mean increase of +39%. Patients with a relative increase over 10% from elevated baseline LDH had a significantly shorter OS compared with patients with ⩽10% change (4.3 vs 15.7 months, log-rank P<0.00623).

Conclusions:

LDH could be a useful marker at baseline and during treatment to predict early response or progression in patients with advanced melanoma who receive anti-PD-1 therapy.