Improved overall survival in melanoma with combined dabrafenib and trametinib

Targeting the mitogen-activated protein kinase pathway in low-grade serous carcinoma of the ovary

Until recently, there has been little change in the management of epithelial ovarian cancer with the majority of women receiving identical systemic therapy, regardless of histological subtype. The heterogeneity of epithelial ovarian cancer is now well established, with distinct subtypes characterized by specific molecular alterations and patterns of clinical behavior. Low-grade serous carcinoma is a rare subtype associated with an indolent biological behavior and inherent resistance to chemotherapy. The mitogen-activated protein kinase pathway plays a prominent role in the pathogenesis of low-grade serous carcinoma, and provides an attractive target for novel therapeutic agents. Selumetinib, a MEK1/2 inhibitor, demonstrates promising efficacy in women with relapsed low-grade serous carcinoma, and further trials of MEK-inhibition are underway. Translational research will be essential to identify predictive biomarkers for this treatment approach.

Biomarkers in melanoma

Malignant melanoma remains the skin cancer with the highest number of mortalities worldwide. While early diagnosis and complete surgical excision remain the best possibility for curing disease, prognosis at the stage of metastasis is still poor. Recent years have brought about considerable advances in terms of understanding the pathogenesis of melanoma and treating advanced disease. The discovery of activating BRAF mutations in around 50% of tumors has led to the introduction of targeted therapies downregulating BRAF signaling output. These have been further refined as combination therapies, which by targeting multiple targets have further improved the clinical outcome. A comparable, potentially even superior therapeutic alternative has been the introduction of immunotherapeutic approaches, including PD-1 and CTLA-4 checkpoint blockade therapies. Despite all genetic knowledge acquired in recent years, a clearly applicable prognostic signature of clinical value has not been established. General prognostic assessment of cutaneous melanoma remains based on clinical and pathological criteria (most importantly tumor thickness). The main challenges lying ahead are to establish a reliable prognostic test effectively determining which tumors will metastasize. Additionally establishing biomarkers which will allow patients to be stratified according to the most promising systemic therapy (immunotherapies and/or BRAF inhibitor therapies) is of utmost importance for patients with metastasized disease. Identifying serum biomarkers enabling disease to be monitored as well as determining tumor properties (i.e. resistance) would also be of great value. While initial results have proven promising, there remains much work to be done.

Combined Therapy with Dabrafenib and Trametinib in BRAF-Mutated Metastatic Melanoma in a Real-Life Setting: The INT Milan Experience

Purpose

Combination therapy with dabrafenib and trametinib is safer and more effective than BRAF inhibitor-based monotherapy for metastatic melanoma.

Methods

We retrospectively analyzed BRAF-mutated metastatic melanoma patients treated at our institution with daily oral dabrafenib 300 mg and trametinib 2 mg from November 2013 to April 2016. This clinical record included both untreated and previously treated stage IV melanomas. Physical examination and laboratory examinations were performed monthly and disease re-evaluations were performed every 3 months.

Results

A total of 48 patients (24 male, 24 female) with BRAF-mutated metastatic melanoma received dabrafenib and trametinib; median age was 48 years (range 23-75). Median follow-up was 362.5 days (range 72-879). Best overall response rate consisted of 6.2% (3 patients) complete response, 64.6% (31) partial response, and 25% ( 12 ) stable disease; median time to best response was 11 weeks (range 5.7-125.5). Progression of disease was seen in 19 patients (39.6%), with median time to progression (TTP) of 26 weeks (range 8-54). A total of 15 patients (31.2%) died due to progression of disease. Median progression-free survival and median overall survival were not reached. To date, 30 patients (62.5%) are still under treatment. A total of 27 (56.2%) patients had at least one adverse event (AE); grade 3-4 AEs were seen in 4 cases (8.3%). The main toxicities were fever (25%), skin rash (14.6%), arthralgias (10.4%), and aspartate aminotransferase/alanine aminotransferase increase (8.3%). Treatment dose was reduced in 7 subjects (14.6%), with only one case of discontinuation due to AE.

Conclusions

Our data, using combined targeted therapy, are in line with the scientific literature in terms of both safety and effectiveness in a real-life setting.

Genomic Alterations in Langerhans Cell Histiocytosis

The discovery of recurrent somatic genomic alterations in Langerhans cell histiocytosis (LCH) has led to a new understanding of LCH as a clonal neoplastic disorder. Most of the abnormalities described to date affect the RAS/RAF/MEK/extracellular-signal-regulated kinase (ERK) pathway: more than 50% of LCH cases carry activating mutations in BRAF, whereas another 10% to 28% carry activating mutations of MAP2K1, which encodes MEK1. The pathogenetic importance of these mutations has been confirmed by reports of significant clinical responses to RAF inhibitors.

Hypoxia-Driven Mechanism of Vemurafenib Resistance in Melanoma

Melanoma is molecularly and structurally heterogeneous, with some tumor cells existing under hypoxic conditions. Our cell growth assays showed that under controlled hypoxic conditions, BRAF(V600E) melanoma cells rapidly became resistant to vemurafenib. By employing both a three-dimensional (3D) spheroid model and a two-dimensional (2D) hypoxic culture system to model hypoxia in vivo, we identified upregulation of HGF/MET signaling as a major mechanism associated with vemurafenib resistance as compared with 2D standard tissue culture in ambient air. We further confirmed that the upregulation of HGF/MET signaling was evident in drug-resistant melanoma patient tissues and mouse xenografts. Pharmacologic inhibition of the c-Met/Akt pathway restored the sensitivity of melanoma spheroids or 2D hypoxic cultures to vemurafenib. Mol Cancer Ther; 15(10); 2442-54. ©2016 AACR.

Ipilimumab in melanoma

INTRODUCTION

The treatment of melanoma is evolving rapidly over the past few years. Patients with BRAFv600 mutations can be treated with a combination of a BRAF-inhibitor and an MEK-inhibitor. Patients with BRAF wild-type tumors and BRAFv600 mutated tumors can be treated with immunotherapy i.e. check point inhibitors.

AREAS COVERED

We conducted a comprehensive review of the literature on the efficacy and predictive markers, safety, and pharmacoeconomics of ipilimumab in melanoma Expert commentary: Ipilimumab was the first check point inhibitor reaching the clinic, gaining FDA and EMA approval for metastatic melanoma in 2011. Ipilimumab was also approved by FDA in the adjuvant setting for patients with high risk, stage III melanoma. The anti-PD1 directed antibodies pembrolizumab and nivolumab are superior to single agent ipilimumab, which is no longer considered the standard first line treatment in metastatic melanoma. The addition ipilimumab to nivolumab is associated with a higher response rate and a better PFS, particularly in patients with PD-L1 negative tumors, albeit at the cost of a steep increase in grade 3-4 adverse event rate. Definitive survival data on this combination are pending and the selection of patients potentially requiring the combination and its pharmacoeconomic implications are to be elucidated.

Individualized strategies to target specific mechanisms of disease in malignant melanoma patients displaying unique mutational signatures

Targeted treatment of advanced melanoma could benefit from the precise molecular characterization of melanoma samples. Using a melanoma-specific selection of 217 genes, we performed targeted deep sequencing of a series of biopsies, from advanced melanoma cases, with a Breslow index of ≥4 mm, and/or with a loco-regional infiltration in lymph nodes or presenting distant metastasis, as well of a collection of human cell lines. This approach detected 3–4 mutations per case, constituting unique mutational signatures associated with specific inhibitor sensitivity. Functionally, case-specific combinations of inhibitors that simultaneously targeted MAPK-dependent and MAPK-independent mechanisms were most effective at inhibiting melanoma growth, against each specific mutational background. These observations were challenged by characterizing a freshly resected biopsy from a metastatic lesion located in the skin and soft tissue and by testing its associated therapy ex vivo and in vivo using melanocytes and patient-derived xenografted mice, respectively.

The results show that upon mutational characterization of advanced melanoma patients, specific mutational profiles can be used for selecting drugs that simultaneously target several deregulated genes/pathways involved in tumor generation or progression.

Analysis of SDHD promoter mutations in various types of melanoma

Objectives

Recently, recurrent mutations in regulatory DNA regions, such as promoter mutations in the TERT gene were identified in melanoma. Subsequently, Weinhold et al. reported SDHD promoter mutations occurring in 10% of melanomas and being associated with a lower overall survival rate. Our study analyzes the mutation rate and clinico-pathologic associations of SDHD promoter mutations in a large cohort of different melanoma subtypes.

Methods

451 melanoma samples (incl. 223 non-acral cutaneous, 38 acral, 33 mucosal, 43 occult, 43 conjunctival and 51 uveal melanoma) were analyzed for the presence of SDHD promoter mutations by Sanger-sequencing. Statistical analysis was performed to screen for potential correlations of SDHD promoter mutation status with various clinico-pathologic criteria.

Results

The SDHD promoter was successfully sequenced in 451 tumor samples. ETS binding site changing SDHD promoter mutations were identified in 16 (4%) samples, of which 5 mutations had not been described previously. Additionally, 5 point mutations not located in ETS binding elements were identified. Mutations in UV-exposed tumors were frequently C>T. One germline C>A SDHD promoter mutation was identified. No statistically significant associations between SDHD promoter mutation status and various clinico-pathologic variables or overall patient survival were observed.

Conclusions

Melanomas harbor recurrent SDHD promoter mutations, which occur primarily as C>T alterations in UV-exposed melanomas. In contrast to the initial report and promoter mutations in the TERT gene, our analysis suggests that SDHD promoter mutations are a relatively rare event in melanoma (4% of tumors) of unclear clinical and prognostic relevance.

Resistant mechanisms to BRAF inhibitors in melanoma

Patients with advanced melanoma have traditionally had very poor prognosis. However, since 2011 better understanding of the biology and epidemiology of this disease has revolutionized its treatment, with newer therapies becoming available. These newer therapies can be classified into immunotherapy and targeted therapy. The immunotherapy arsenal includes inhibitors of CTLA4, PD-1 and PDL-1, while targeted therapy focuses on BRAF and MEK. BRAF inhibitors (vemurafenib, dabrafenib) have shown benefit in terms of overall survival (OS) compared to chemotherapy, and their combination with MEK inhibitors has recently been shown to improve progression-free survival (PFS), compared with monotherapy with BRAF inhibitors. However, almost 20% of patients initially do not respond, due to intrinsic resistance to therapy and, of those who do, most eventually develop mechanisms of acquired resistance, including reactivation of the MAP kinase pathway, persistent activation of receptor tyrosine kinase (RTKS) receptor, activation of phosphatidyinositol-3OH kinase, overexpression of epidermal growth factor receptor (EGFR), and interactions with the tumor microenvironment. Herein we comment in detail on mechanisms of resistance to targeted therapy and discuss the strategies to overcome them.

Combination of antibodies directed against different ErbB3 surface epitopes prevents the establishment of resistance to BRAF/MEK inhibitors in melanoma

Patients with metastatic melanoma bearing V600 mutations in BRAF oncogene clinically benefit from the treatment with BRAF inhibitors alone or in combination with MEK inhibitors. However, a limitation to such treatment is the occurrence of resistance. Tackling the adaptive changes helping cells survive from drug treatment may offer new therapeutic opportunities. Very recently the ErbB3 receptor has been shown to act as a central node promoting survival of BRAF mutated melanoma. In this paper we first demonstrate that ErbB3/AKT hyperphosphorylation occurs in BRAF mutated melanoma cell lines following exposure to BRAF and/or MEK inhibitors. This strongly correlates with increased transcriptional activation of its ligand neuregulin. Anti-ErbB3 antibodies impair the establishment of de novo cell resistance to BRAF inhibition in vitro. In order to more potently ablate ErbB3 activity we used a combination of two anti-ErbB3 antibodies directed against distinct epitopes of its extracellular domain. These two antibodies in combo with BRAF/MEK inhibitors potently inhibit in vitro cell growth and tumor regrowth after drug withdrawal in an in vivo xenograft model. Importantly, residual tumor masses from mice treated by the antibodies and BRAF/ERK inhibitors combo are characterized almost exclusively by large necrotic areas with limited residual areas of tumor growth. Taken together, our findings support the concept that triple therapy directed against BRAF/MEK/ErbB3 may be able to provide durable control of BRAF mutated metastatic melanoma.

Evaluating cost benefits of combination therapies for advanced melanoma

BACKGROUND

Although a number of monoimmunotherapies and targeted therapies are available to treat BRAF+ advanced melanoma, response rates remain relatively low in the range of 22-53% with progression-free survival (PFS) in the range of 4.8-8.8 months. Recently, combination targeted therapies have improved response rates to about 66-69%, PFS to 11.0-12.6 months and overall survival (OS) to 25.1-25.6 months. While combination immunotherapies have improved response rates of 67 compared with 19-29% with monotherapies and improved PFS of 11.7 compared with 4.4-5.8 months with monotherapies, the OS benefit is yet to be established in phase 3 trials. As healthcare costs continue to rise, US payers have a predominant interest in assessing the value of available treatments. Therefore, a cost-benefit model was developed to evaluate the value of treating BRAF+ advanced melanoma with two combination therapies: nivolumab + ipilimumab (N+I) and dabrafenib + trametinib (D+T).

SCOPE

The model was used to estimate total costs, total costs by expenditure category, cost per month of PFS and cost per responder for the payer, and societal perspectives of treating advanced melanoma patients with the BRAF V600 mutation using combination targeted therapy (D+T) or combination immunotherapy (N+I). The model followed patients from initiation of treatment to the point of progression or death. Deterministic and probabilistic sensitivity analyses were conducted to evaluate the robustness of the results and to understand the dispersion of simulated results.

FINDINGS

Based on a hypothetical payer with one million covered lives, it was expected that fourteen metastatic melanoma patients with the BRAF V600 mutation would be treated each year. Cost-benefit with N+I and D+T was simulated from the payer perspective. The cost per month of PFS for N+I was $22,162, while that for D+T was $17,716 (-$4,446 cost difference); the cost per responder for N+I was $388,746 and that for D+T was $282,429 (-$106,316 cost difference). The cost per month of PFS and per responder from the societal perspective resembled the patterns observed from the payer's perspective: the cost per month of PFS for N+I was $22,843, while that for D+T was $18,283 (-$4,560 cost difference). The cost per responder for N+I was $400,695 and that for D+T was $291,473 (-$109,222 cost difference). The totals of travel and treatment time for N+I and D+T were 58 hours and 3.9 hours per patient, respectively, of which total infusion time for N+I accounted for a majority - 59% - of the 58 hours. Sensitivity analyses indicated that results were most sensitive to model inputs for median PFS, body weight, and drug cost. Moreover, D+T is likely associated with a lower cost per month of PFS and cost per responder than N+I, except at low body weights (less than 57 kg).

CONCLUSION

The model presented in this study was used to analyze the clinical and economic benefit of using combination therapies in advanced melanoma patients with the BRAF V600 mutation. This analysis suggests D+T therapy is associated with less patient time and lower costs relative to N+I to gain similar PFS and overall response rate (ORR) benefits.

Risk of Ophthalmic Adverse Effects in Patients Treated with MEK Inhibitors: A Systematic Review and Meta-Analysis

OBJECTIVES

This meta-analysis aims to evaluate the risk of ophthalmic adverse effects associated with MEK inhibitors.

METHODS

A literature search was conducted in PubMed and the Cochrane Library to identify randomized clinical trials (RCTs) which have been designed to evaluate the efficacy and safety of MEK inhibitors. Overall risk of ophthalmic adverse effects, chorioretinopathy, retinal detachment, blurred vision, uveitis, and eye haemorrhage were the assessed outcomes. Peto odds ratios (ORs) with their 95% confidence intervals (CIs) were pooled. Between-study heterogeneity was assessed using I2 statistics.

RESULTS

Thirteen RCTs were included in this meta-analysis. Overall, MEK inhibitors were associated with an increased risk of ophthalmic adverse effects (OR 2.24; 95% CI 1.75-2.87; p < 0.0001; I2 = 86.5%). An increased risk was also estimated for chorioretinopathy (OR 5.44; 95% CI 2.89-10.23; p < 0.0001; I2 = 0%), retinal detachment (OR 6.54; 95% CI 3.28-13.03; p < 0.0001; I2 = 0%), and blurred vision (OR 2.30; 95% CI 1.50-3.54; p < 0.0001; I2 = 60.1%), but not for uveitis (OR 0.99; 95% CI 0.14-7.03; p = 0.991; I2 = 2.9%) or eye haemorrhage (OR 0.72; 95% CI 0.04-12.39; p = 0.824; I2 = 29.8%).

CONCLUSIONS

Treatment with MEK inhibitors seems to increase the risk of ophthalmic adverse effects. A need for monitoring the safety of this class of drugs exists. Regulators, clinicians, and other health care professionals must, together, be involved in this process.

Combined vemurafenib and fotemustine in patients with BRAF V600 melanoma progressing on vemurafenib

Background

BRAF inhibitor vemurafenib achieves high response rate and an improvement in survival in patients with BRAF-mutated metastatic melanoma. However, median progression-free survival is only 6.9 months in the phase 3 study. Retrospective analyses suggest that treatment with BRAF inhibitors beyond initial progression might be associated with improved overall survival. We aimed to prospectively investigate the activity of prolonged treatment with vemurafenib and the addition of fotemustine in patients with systemic progression on prior single-agent BRAF inhibitor.

Patients and Methods

In this two-centres, single-arm Phase 2 trial, we enrolled patients with systemic progressive disease during single-agent vemurafenib treatment. Participants received vemurafenib 960 mg twice daily or dose administered at time of disease progression with vemurafenib previous treatment and fotemustine 100 mg/m2 intravenously every three weeks. The primary endpoint was PFS.

Results

Thirty-one patients were enrolled in the study; 16 patients had brain metastases at baseline. Median PFS was 3.9 months and 19 patients (61.3%) achieved disease control (1 CR, 4 PR, 14 SD). For patients achieving disease control, median duration of treatment was 6 months. Median OS was 5.8 months from enrolment and 15.4 months from start of previous vemurafenib. Five patients (16.1%) had a G3-4 AE, the most common being thrombocytopenia, which occurred in 3 patients.

This trial is registered with ClinicalTrials.gov number NCT01983124.

Conclusion

The combination of vemurafenib plus fotemustine has clinical activity and an acceptable safety profile in BRAF-refractory patients.

Cancer pharmacogenomics, challenges in implementation, and patient-focused perspectives

Cancer pharmacogenomics is an evolving landscape and has the potential to significantly impact cancer care and precision medicine. Harnessing and understanding the genetic code of both the patient (germline) and the tumor (somatic) provides the opportunity for personalized dose and therapy selection for cancer patients. While germline DNA is useful in understanding the pharmacokinetic and pharmacodynamic disposition of a drug, somatic DNA is particularly useful in identifying drug targets and predicting drug response. Molecular profiling of somatic DNA has resulted in the current breadth of targeted therapies available, expanding the armamentarium to battle cancer. This review provides an update on cancer pharmacogenomics and genomics-based medicine, challenges in applying pharmacogenomics to the clinical setting, and patient perspectives on the use of pharmacogenomics to personalize cancer therapy.

(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.

Immune Cell Regulatory Pathways Unexplored as Host-Directed Therapeutic Targets for Mycobacterium tuberculosis: An Opportunity to Apply Precision Medicine Innovations to Infectious Diseases

The lack of novel antimicrobial drugs in development for tuberculosis treatment has provided an impetus for the discovery of adjunctive host-directed therapies (HDTs). Several promising HDT candidates are being evaluated, but major advancement of tuberculosis HDTs will require understanding of the master or "core" cell signaling pathways that control intersecting immunologic and metabolic regulatory mechanisms, collectively described as "immunometabolism." Core regulatory pathways conserved in all eukaryotic cells include poly (ADP-ribose) polymerases (PARPs), sirtuins, AMP-activated protein kinase (AMPK), and mechanistic target of rapamycin (mTOR) signaling. Critical interactions of these signaling pathways with each other and their roles as master regulators of immunometabolic functions will be addressed, as well as how Mycobacterium tuberculosis is already known to influence various other cell signaling pathways interacting with them. Knowledge of these essential mechanisms of cell function regulation has led to breakthrough targeted treatment advances for many diseases, most prominently in oncology. Leveraging these exciting advances in precision medicine for the development of innovative next-generation HDTs may lead to entirely new paradigms for treatment and prevention of tuberculosis and other infectious diseases.

Checkpoint-Inhibitoren in der Immuntherapie: Ein Meilenstein in der Behandlung des malignen Melanoms

Seit Jahrzehnten ist bekannt, dass Tumoren vom Immunsystem erkannt und zerstört werden können. Diese, vor allem in Tierversuchen gewonnene Erkenntnis konnte jedoch in der Vergangenheit nicht zum Nutzen unserer Patienten umgesetzt werden, da immunonkologische Therapieansätze in den letzten Jahrzehnten in der Anwendung beim Menschen stets versagt haben. Daher hat, mit Ausnahme der adjuvanten Interferontherapie, keines dieser Verfahren den Einzug in die klinische Versorgung gefunden. Langzeitüberleben unter guter Lebensqualität war dabei sehr wenigen Patienten vorbehalten. Mit den neuen immunologischen Therapieansätzen wird jedoch sowohl das Langzeitüberleben als auch die Lebensqualität onkologischer Patienten neu definiert. Auf die neuen "Immun-Checkpoint-Inhibitoren" spricht erstmals ein relevanter Teil der behandelten Patienten an und diese zeigen in der Regel langandauernde Remissionen bis hin zur Heilung. Schon jetzt ist klar, dass die Immuntherapie in Zukunft eine der wesentlichen Therapiesäulen bei der Behandlung des metastasierten Melanoms und auch vieler anderer fortgeschrittener Tumoren bilden wird. In dieser Übersicht werden die wichtigsten neuen Therapiemodalitäten besprochen und sowohl deren Wirkprinzip als auch klinische Daten zum Therapieansprechen und zu erwartenden Nebenwirkungen der Therapie referiert.

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.

Therapeutic implications of melanoma heterogeneity

Over the last decade, the treatment of metastatic melanoma has been revolutionized by the translation of molecular insights into therapeutic benefit for patients. These include advances in immunotherapeutic and small-molecule approaches aimed at destroying cells with immunogenic antigens or gene mutations. Despite these advances, the limited durability of clinical response and eventual disease progression underscores a need for better understanding of mechanisms underlying tumor development. Current targeted therapies are developed partly based on the rationale that tumors are primarily clonal with respect to mutant oncogene or cell surface antigen target. However, with the advancement of cell isolation and transplantation approaches coupled with deep sequencing and mutation detection techniques, it has become increasingly clear that tumors are polyclonal. As a result, sensitive malignant cells are eradicated by treatment while the remaining tumor cell populations are conferred varying degrees of resistance and survival advantages by harbouring or acquiring certain epigenetic and genetic abnormalities. Tumor heterogeneity thus represents a major obstacle to the successful application of current therapies. Gaining insights into the cellular and molecular aspects of tumor diversity will not only facilitate the development and selection of therapeutic targets but also promote the evolution of precision medicine. In this viewpoint, we will discuss the implications of tumor heterogeneity for the treatment of metastatic melanoma and propose approaches to accelerate the translation of scientific discovery into improved clinical outcomes.

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.

A Platform for Rapid, Quantitative Assessment of Multiple Drug Combinations Simultaneously in Solid Tumors In Vivo

While advances in high-throughput screening have resulted in increased ability to identify synergistic anti-cancer drug combinations, validation of drug synergy in the in vivo setting and prioritization of combinations for clinical development remain low-throughput and resource intensive. Furthermore, there is currently no viable method for prospectively assessing drug synergy directly in human patients in order to potentially tailor therapies. To address these issues we have employed the previously described CIVO platform and developed a quantitative approach for investigating multiple combination hypotheses simultaneously in single living tumors. This platform provides a rapid, quantitative and cost effective approach to compare and prioritize drug combinations based on evidence of synergistic tumor cell killing in the live tumor context. Using a gemcitabine resistant model of pancreatic cancer, we efficiently investigated nine rationally selected Abraxane-based combinations employing only 19 xenografted mice. Among the drugs tested, the BCL2/BCLxL inhibitor ABT-263 was identified as the one agent that synergized with Abraxane^® to enhance acute induction of localized apoptosis in this model of human pancreatic cancer. Importantly, results obtained with CIVO accurately predicted the outcome of systemic dosing studies in the same model where superior tumor regression induced by the Abraxane/ABT-263 combination was observed compared to that induced by either single agent. This supports expanded use of CIVO as an in vivo platform for expedited in vivo drug combination validation and sets the stage for performing toxicity-sparing drug combination studies directly in cancer patients with solid malignancies.

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.

Molecular characterisation of cutaneous melanoma: creating a framework for targeted and immune therapies

Large-scale genomic analyses of cutaneous melanoma have revealed insights into the aetiology and heterogeneity of this disease, as well as opportunities to further personalise treatment for patients with targeted and immune therapies. Herein, we review the proposed genomic classification of cutaneous melanoma from large-scale next-generation sequencing studies, including the largest integrative analysis of melanoma from The Cancer Genome Atlas (TCGA) Network. We examine studies that have identified molecular features of melanomas linked to immune checkpoint inhibitor response. In addition, we draw attention to low-frequency actionable mutations and highlight frequent non-coding mutations in melanoma where little is known about their biological function that may provide novel avenues for the development of treatment strategies for melanoma patients.

The evolution of combined molecular targeted therapies to advance the therapeutic efficacy in melanoma: a highlight of vemurafenib and cobimetinib

Metastatic melanoma is an aggressive, rapidly progressive disease which historically had very few effective treatment options. However, since 2011, the therapeutic landscape of melanoma has undergone a dramatic transformation with two distinct approaches and has catalyzed the successful advancement in the clinical field of immuno-oncology. In addition, the recognition of a key oncogenic driver mutation in melanoma, BRAF, stimulated the development of multiple potent kinase inhibitors which has also influenced the expansion and use of targeted agents in the practice of oncology. Vemurafenib, the initial BRAF inhibitor approved for the treatment of melanoma, was the first agent to demonstrate rapid clinical responses and significantly improved survival which was a clinical breakthrough in the treatment of melanoma. Although exciting and practice changing, the unparalleled responses with vemurafenib are usually not sustained. Further investigations delineated several mechanisms of acquired resistance which are most often mediated by the upregulation of the MAPK pathway. MEK inhibitors, another class of small-molecule inhibitors, were developed as an alternative agent to suppress the MAPK pathway downstream, independent from BRAF activation. Multiple studies have demonstrated the improvement in antitumor activity when MEK inhibitors are used in combination with BRAF inhibitors in the treatment of metastatic melanoma. This is a review of the investigations that led to the US Food and Drug Administration approval in 2015 of the combination of vemurafenib and cobimetinib, adding to the quickly growing armament for the treatment of advanced or metastatic melanoma with a BRAF V600 mutation.

Redox Homeostasis and Cellular Antioxidant Systems: Crucial Players in Cancer Growth and Therapy

Reactive oxygen species (ROS) and their products are components of cell signaling pathways and play important roles in cellular physiology and pathophysiology. Under physiological conditions, cells control ROS levels by the use of scavenging systems such as superoxide dismutases, peroxiredoxins, and glutathione that balance ROS generation and elimination. Under oxidative stress conditions, excessive ROS can damage cellular proteins, lipids, and DNA, leading to cell damage that may contribute to carcinogenesis. Several studies have shown that cancer cells display an adaptive response to oxidative stress by increasing expression of antioxidant enzymes and molecules. As a double-edged sword, ROS influence signaling pathways determining beneficial or detrimental outcomes in cancer therapy. In this review, we address the role of redox homeostasis in cancer growth and therapy and examine the current literature regarding the redox regulatory systems that become upregulated in cancer and their role in promoting tumor progression and resistance to chemotherapy.

Small molecule drugs with immunomodulatory effects in cancer

Immunotherapy shows promise for positively changing the landscape of the management of many advanced solid tumors, including gastrointestinal (GI) malignancies. Many of these developments have been focused on vaccine-based, monoclonal antibody therapies and more recently, checkpoint inhibitors, although many small molecule inhibitors can function as immunomodulators. Small molecule compounds have several advantages over conventional immunotherapeutic agents including: ease of production and the potential for oral administration. There is a potential niche for small molecule immunomodulators to enhance the efficacy of existing immunotherapeutic and cytotoxic agents. This article focuses on two categories of small molecule compounds with immunomodulatory effects: IDO and MEK inhibitors. Indoleamine -2, 3- dioxygenase (IDO) is known for its effects in tumor immunity. IDO inhibitors are generally well-tolerated and have the potential to enhance anti-tumor responses when combined with checkpoint inhibitors. MEK inhibitors affect signal transduction of the RAS-RAF-MEK pathway and numerous MEK inhibitors are currently being investigated in solid tumors. Small molecule immunomodulators are currently being investigated for their potential role in augmenting the effects of conventional immunotherapeutic agents although further research is required to identify those patients most likely to respond to combination therapy.

Dendritic cell vaccination in melanoma patients: From promising results to future perspectives

Dendritic cells (DCs) play an important role in the induction of antitumor immunity. Therefore, they are used as anti-cancer vaccines in clinical studies in various types of cancer. DC vaccines are generally well tolerated and able to induce antigen-specific T cell responses in melanoma patients. After DC vaccinations, functional tumor-specific T cells are more frequently detected in stage III melanoma patients, as compared to patients with advanced melanoma, indicating that the tumor load influences immunological responses. Furthermore, long-lasting clinical responses were rarely seen in metastatic melanoma patients after DC vaccination. Since more potent treatment options are available, e.g. immune checkpoint inhibitors and targeted therapy, DC vaccination as monotherapy may not be preferred in the treatment of advanced melanoma. However, encouraging results of DC vaccines combined with ipilimumab have been reported in advanced melanoma patients with an objective response rate of 38%. DC vaccines show promising clinical results in stage III patients, although clinical efficacy still needs to be proven in a phase 3 trial. The clinical and immunological results of DC vaccination in stage III melanoma patients might be further improved by using naturally circulating DCs (myeloid DCs and plasmacytoid DCs) and neoantigens to load DCs.

Precision Oncology Medicine: The Clinical Relevance of Patient-Specific Biomarkers Used to Optimize Cancer Treatment

Precision medicine in oncology is the result of an increasing awareness of patient-specific clinical features coupled with the development of genomic-based diagnostics and targeted therapeutics. Companion diagnostics designed for specific drug-target pairs were the first to widely utilize clinically applicable tumor biomarkers (eg, HER2, EGFR), directing treatment for patients whose tumors exhibit a mutation susceptible to an FDA-approved targeted therapy (eg, trastuzumab, erlotinib). Clinically relevant germline mutations in drug-metabolizing enzymes and transporters (eg, TPMT, DPYD) have been shown to impact drug response, providing a rationale for individualized dosing to optimize treatment. The use of multigene expression-based assays to analyze an array of prognostic biomarkers has been shown to help direct treatment decisions, especially in breast cancer (eg, Oncotype DX). More recently, the use of next-generation sequencing to detect many potential "actionable" cancer molecular alterations is further shifting the 1 gene-1 drug paradigm toward a more comprehensive, multigene approach. Currently, many clinical trials (eg, NCI-MATCH, NCI-MPACT) are assessing novel diagnostic tools with a combination of different targeted therapeutics while also examining tumor biomarkers that were previously unexplored in a variety of cancer histologies. Results from ongoing trials such as the NCI-MATCH will help determine the clinical utility and future development of the precision-medicine approach.

Ipilimumab administered to metastatic melanoma patients who progressed after dendritic cell vaccination

Background: Ipilimumab has proven to be effective in metastatic melanoma patients. The purpose of this study was to determine the efficacy of ipilimumab in advanced melanoma patients who showed progressive disease upon experimental dendritic cell (DC) vaccination. Methods: Retrospective analysis of 48 stage IV melanoma patients treated with ipilimumab after progression upon DC vaccination earlier in their treatment. DC vaccination was given either as adjuvant treatment for stage III disease (n = 18) or for stage IV disease (n = 30). Ipilimumab (3 mg/kg) was administered every 3 weeks for up to 4 cycles. Results: Median time between progression upon DC vaccination and first gift of ipilimumab was 5.4 mo. Progression-free survival (PFS) rates for patients that received ipilimumab after adjuvant DC vaccination, and patients that received DC vaccination for stage IV melanoma, were 35% and 7% at 1 y and 35% and 3% at 2 y, while the median PFS was 2.9 mo and 3.1 mo, respectively. Median overall survival of patients pre-treated with adjuvant DC vaccination for stage III melanoma was not reached versus 8.0 mo (95% CI, 5.2–10.9) in the group pre-treated with DC vaccination for stage IV disease (HR of death, 0.36; p = 0.017). Grade 3 immune-related adverse events occurred in 19% of patients and one death (2%) was related to ipilimumab. Conclusions: Clinical responses to ipilimumab were found in a considerable number of advanced melanoma patients with progression after adjuvant DC vaccination for stage III disease, while the effect was very limited in patients who showed progression after DC vaccination for stage IV disease.

BRAF(V600E) Kinase Domain Duplication Identified in Therapy-Refractory Melanoma Patient-Derived Xenografts

The therapeutic landscape of melanoma is improving rapidly. Targeted inhibitors show promising results, but drug resistance often limits durable clinical responses. There is a need for in vivo systems that allow for mechanistic drug resistance studies and (combinatorial) treatment optimization. Therefore, we established a large collection of patient-derived xenografts (PDXs), derived from BRAF^V600E, NRAS^Q61, or BRAF^WT/NRAS^WT melanoma metastases prior to treatment with BRAF inhibitor and after resistance had occurred. Taking advantage of PDXs as a limitless source, we screened tumor lysates for resistance mechanisms. We identified a BRAF^V600E protein harboring a kinase domain duplication (BRAF^V600E/DK) in ∼10% of the cases, both in PDXs and in an independent patient cohort. While BRAF^V600E/DK depletion restored sensitivity to BRAF inhibition, a pan-RAF dimerization inhibitor effectively eliminated BRAF^V600E/DK-expressing cells. These results illustrate the utility of this PDX platform and warrant clinical validation of BRAF dimerization inhibitors for this group of melanoma patients.

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Patient-derived xenograft (PDX) platform comprises 89 metastatic melanoma tumors

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Platform includes several pre-vemurafenib and vemurafenib-resistant PDXs

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Duplication of the BRAF^V600E kinase domain is identified as a resistance mechanism

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Pan-RAF dimerization inhibitor LY3009120 eliminates melanoma cells with this duplication

The Combination of Vemurafenib and Procaspase-3 Activation Is Synergistic in Mutant BRAF Melanomas

The development of vemurafenib resistance limits the long-term efficacy of this drug for treatment of metastatic melanomas with the (V600E)BRAF mutation. Inhibition of downstream MAPK signaling with vemurafenib induces apoptotic cell death mediated by caspase-3, suggesting that addition of a procaspase-3 activator could enhance anticancer effects. Here, we show that the combination of PAC-1, a procaspase-activating compound, and vemurafenib is highly synergistic in enhancing caspase-3 activity and apoptotic cell death in melanoma cell lines harboring the (V600E)BRAF mutation. In vivo, the combination displays a favorable safety profile in mice and exerts significant antitumor effects. We further demonstrate that addition of PAC-1 to the clinically useful combination of vemurafenib and a MEK inhibitor, trametinib, starkly enhances the caspase-3 activity and proapoptotic effect of the combination. Moreover, addition of low concentration PAC-1 also delays the regrowth of cells following treatment with vemurafenib. Finally, PAC-1 remains potent against vemurafenib-resistant A375VR cells in cell culture and synergizes with vemurafenib to exert antitumor effects on A375VR cell growth in vivo Collectively, our data suggest that inhibition of MAPK signaling combined with concurrent procaspase-3 activation is an effective strategy to enhance the antitumor activity of vemurafenib and mitigate the development of resistance. Mol Cancer Ther; 15(8); 1859-69. ©2016 AACR.

Targeting RRM2 and Mutant BRAF Is a Novel Combinatorial Strategy for Melanoma

The majority of patients with melanoma harbor mutations in the BRAF oncogene, thus making it a clinically relevant target. However, response to mutant BRAF inhibitors (BRAFi) is relatively short-lived with progression-free survival of only 6 to 7 months. Previously, we reported high expression of ribonucleotide reductase M2 (RRM2), which is rate-limiting for de novo dNTP synthesis, as a poor prognostic factor in patients with mutant BRAF melanoma. In this study, the notion that targeting de novo dNTP synthesis through knockdown of RRM2 could prolong the response of melanoma cells to BRAFi was investigated. Knockdown of RRM2 in combination with the mutant BRAFi PLX4720 (an analog of the FDA-approved drug vemurafenib) inhibited melanoma cell proliferation to a greater extent than either treatment alone. This occurred in vitro in multiple mutant BRAF cell lines and in a novel patient-derived xenograft (PDX) model system. Mechanistically, the combination increased DNA damage accumulation, which correlated with a global decrease in DNA damage repair (DDR) gene expression and increased apoptotic markers. After discontinuing PLX4720 treatment, cells showed marked recurrence. However, knockdown of RRM2 attenuated this rebound growth both in vitro and in vivo, which correlated with maintenance of the senescence-associated cell-cycle arrest.

IMPLICATIONS

Inhibition of RRM2 converts the transient response of melanoma cells to BRAFi to a stable response and may be a novel combinatorial strategy to prolong therapeutic response of patients with melanoma. Mol Cancer Res; 14(9); 767-75. ©2016 AACR.

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.

Use of a Tissue Engineered Human Skin Model to Investigate the Effects of Wounding and of an Anti-Inflammatory on Melanoma Cell Invasion

An increasing number of studies suggest inflammation stimulates tumour invasion. In melanoma, despite recent advances in targeted therapy and immunomodulatory therapies, this cancer remains difficult to treat. Our previous studies show melanoma cells interact with skin cells in their invasion into tissue engineered skin and suggest inflammation stimulates invasion. The aim of this study was to investigate the use of an anti-inflammatory on melanoma invasion. To do this we developed a wounded and inflamed in vitro 3D melanoma model in which to investigate the use of an anti-inflammatory on melanoma invasion. The tissue engineered skin model was based on human de-epidermised acellular dermis to which keratinocytes, fibroblasts and three different melanoma cell lines were added in various combinations. A simple incisional wound was made in the model and TNF-α and fibrin were added to simulate conditions of inflammation. Topical ibuprofen in a hydrogel was added and the extent of melanoma invasion into the dermis was assessed under the various conditions. The results showed that penetration of two of the cell lines (HBL and A375SM) into the tissue engineered skin was exacerbated by wounding and ibuprofen significantly decreased invasion of A375SM cells and slightly reduced invasion of HBL cells. A third cell line, C8161, was aggressively invasive under all conditions to an extent that was not influenced by wounding, TNF-α or the addition of ibuprofen. In summary, the results for one these cell lines (and a trend for a second cell line) support the hypothesis that a wound environment is conducive to melanoma invasion but the local addition of an anti-inflammatory drug such as ibuprofen may attenuate invasion.

Dabrafenib in an elderly patient with metastatic melanoma and BRAF V600R mutation: a case report

Background

Approximately 50 % of malignant melanomas harbor activating point mutations in the BRAF gene. Typically, these mutations result in the substitution of the amino acid valine at codon 600 of the gene, and 90–95 % of mutations are either BRAF^V600E or BRAF^V600K. Specific BRAF inhibitors such as dabrafenib and vemurafenib are the mainstays of treatment in patients with metastatic BRAF-mutant malignant melanomas. The third most common BRAF mutation is V600R, which also leads to increased BRAF signaling. Although evidence exists about the activity of dabrafenib and vemurafenib in patients with the BRAF^V600R mutation, these patients have been systematically excluded from recent trials with targeted therapies.

Case presentation

Here, we report the positive results in terms of survival and quality of life obtained with dabrafenib in an 80-year-old Caucasian male patient with a Charlson Comorbidity Index of 8 diagnosed with metastatic malignant melanoma harboring the BRAF^V600R mutation. Our patient was treated with dabrafenib for 7 months with minimal toxicity. We also report exploratory analyses of circulating tumor DNA during targeted treatment. Interestingly, the mutation was not detected after starting treatment and became detectable before radiological disease progression.

Conclusions

Our report suggests that (1) a relevant benefit can be obtained with a BRAF inhibitor in real-world patients with a malignant melanoma harboring a BRAF^V600R mutation, and that (2) circulating tumor DNA detection might be of help in assessing tumor burden in everyday clinical practice. The results reported here should encourage the inclusion of patients with BRAF^V600R-mutated malignant melanomas in future prospective clinical trials with BRAF inhibitors.

Biomarkers in Melanoma: Lessons from Translational Medicine

The treatment landscape for advanced melanoma has been rapidly evolving. As new therapies become available, there is a need for better biomarkers to detect disease, guide patient selection, and monitor for response. The use of tumor genetics has been able to predict responses to targeted therapy in melanoma. However, the role of biomarkers in melanoma detection, monitoring, and immunotherapy has been less successful and is still being defined. Translational studies in many areas of melanoma are being performed to identify biomarkers and validate their clinical role. In this review, we examine the status of biomarkers in melanoma and areas of future development.

Adjuvant treatment for stage III melanoma in the era of targeted medicine and immunotherapy

The accelerated development in the treatment of metastatic melanoma, both in molecular targeted therapy and immunotherapy, is already starting to impact on adjuvant therapy in stage III melanoma. Following the approval of ipilimumab for adjuvant therapy in melanoma, clinical trials assessing other checkpoint modulators and MAPK pathway inhibitors as adjuvant treatments for melanoma are currently ongoing. As results from these trials mature in the next few years, a change in the landscape of adjuvant treatment for melanoma is expected, resulting in new challenges in treatment decisions such as optimizing patients selection through predictive and prognostic biomarkers, and management of treatment related adverse events, in particular immune related toxicities.

Avoiding Severe Toxicity From Combined BRAF Inhibitor and Radiation Treatment: Consensus Guidelines from the Eastern Cooperative Oncology Group (ECOG)

BRAF kinase gene V600 point mutations drive approximately 40% to 50% of all melanomas, and BRAF inhibitors (BRAFi) have been found to significantly improve survival outcomes. Although radiation therapy (RT) provides effective symptom palliation, there is a lack of toxicity and efficacy data when RT is combined with BRAFi, including vemurafenib and dabrafenib. This literature review provides a detailed analysis of potential increased dermatologic, pulmonary, neurologic, hepatic, esophageal, and bowel toxicity from the combination of BRAFi and RT for melanoma patients described in 27 publications. Despite 7 publications noting potential intracranial neurotoxicity, the rates of radionecrosis and hemorrhage from whole brain RT (WBRT), stereotactic radiosurgery (SRS), or both do not appear increased with concurrent or sequential administration of BRAFis. Almost all grade 3 dermatitis reactions occurred when RT and BRAFi were administered concurrently. Painful, disfiguring nondermatitis cutaneous reactions have been described from concurrent or sequential RT and BRAFi administration, which improved with topical steroids and time. Visceral toxicity has been reported with RT and BRAFi, with deaths possibly related to bowel perforation and liver hemorrhage. Increased severity of radiation pneumonitis with BRAFi is rare, but more concerning was a potentially related fatal pulmonary hemorrhage. Conversely, encouraging reports have described patients with leptomeningeal spread and unresectable lymphadenopathy rendered disease free from combined RT and BRAFi. Based on our review, the authors recommend holding BRAFi and/or MEK inhibitors ≥3 days before and after fractionated RT and ≥1 day before and after SRS. No fatal reactions have been described with a dose <4 Gy per fraction, and time off systemic treatment should be minimized. Future prospective data will serve to refine these recommendations.

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.

Intralesional PV-10 for in-transit melanoma-A single-center experience

BACKGROUND AND OBJECTIVES

Patients with in-transit melanoma metastasis have longer median survival than patients with distant metastatic disease. Furthermore, local disease control is an important endpoint for symptom management. The treatment of unresectable loco-regional recurrence or in-transit disease has been historically managed with a combination of treatments including surgery, radiotherapy, isolated limb infusion or perfusion as well as systemic therapies. Intralesional PV-10 has been used at Peter MacCallum Cancer Centre since 2010, and the current report presents a retrospective analysis of patient outcomes, reporting the response rates, durability of responses, and observed toxicities.

METHODS

Records were analyzed retrieving details of 19 patients treated with PV-10 over a 4-year period from 2010 to 2014. Medical records were reviewed for these patients and data extracted.

RESULTS

Nineteen patients with in-transit melanoma were treated with intralesional PV-10 between 2010 and 2014. Disease control (complete or partial response or disease stability) was achieved in 68% of patients with 26% having a complete response. This was achieved with minimal associated toxicity.

CONCLUSIONS

PV-10 is an effective, durable, well-tolerated treatment tool with an acceptable side effect profile for the management of unresectable in-transit melanoma. J. Surg. Oncol. 2016;114:380-384. © 2016 Wiley Periodicals, Inc.

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.

[ESMO ECCO 2015: The highlights of immunotherapy and targeted therapies]

The ESMO/ECC congress (European Society for Medical Oncology/European Cancer Congress) took place in Vienna, Austria, September 25-29. The main topic of the conference was immunotherapies especially in advanced kidney cancer with nivolumab in phase III and in metastatic lung cancer with atezolizumab in phase II. Targeted therapies were also highlighted with cabozantinib proposed in advanced renal cancer or everolimus in differenciated neuroendocrine tumors grade 1 or 2. Furthermore the current challenges remain unchanged: improving patients' care through better selection and finding biomarkers using simple samples (blood or urine). Also early phases and personalized medicine found their place in the different presentations and were highlighted largely bringing new approaches in the treatment of metastatic patients.

Targeted Therapy and Checkpoint Immunotherapy Combinations for the Treatment of Cancer

Many advances in the treatment of cancer have been driven by the development of targeted therapies that inhibit oncogenic signaling pathways and tumor-associated angiogenesis, as well as by the recent development of therapies that activate a patient's immune system to unleash antitumor immunity. Some targeted therapies can have effects on host immune responses, in addition to their effects on tumor biology. These immune-modulating effects, such as increasing tumor antigenicity or promoting intratumoral T cell infiltration, provide a rationale for combining these targeted therapies with immunotherapies. Here, we discuss the immune-modulating effects of targeted therapies against the MAPK and VEGF signaling pathways, and how they may synergize with immunomodulatory antibodies that target PD1/PDL1 and CTLA4. We critically examine the rationale in support of these combinations in light of the current understanding of the underlying mechanisms of action of these therapies. We also discuss the available preclinical and clinical data for these combination approaches and their implications regarding mechanisms of action. Insights from these studies provide a framework for considering additional combinations of targeted therapies and immunotherapies for the treatment of cancer.

Application of Dual Inhibition Concept within Looped Autoregulatory Systems toward Antivirulence Agents against Pseudomonas aeruginosa Infections

Pseudomonas aeruginosa quorum-sensing (QS) is a sophisticated network of genome-wide regulation triggered in response to population density. A major component is the self-inducing pseudomonas quinolone signal (PQS) QS system that regulates the production of several nonvital virulence- and biofilm-related determinants. Hence, QS circuitry is an attractive target for antivirulence agents with lowered resistance development potential and a good model to study the concept of polypharmacology in autoloop-regulated systems per se. Based on the finding that a combination of PqsR antagonist and PqsD inhibitor synergistically lowers pyocyanin, we have developed a dual-inhibitor compound of low molecular weight and high solubility that targets PQS transcriptional regulator (PqsR) and PqsD, a key enzyme in the biosynthesis of PQS-QS signal molecules (HHQ and PQS). In vitro, this compound markedly reduced virulence factor production and biofilm formation accompanied by a diminished content of extracellular DNA (eDNA). Additionally, coadministration with ciprofloxacin increased susceptibility of PA14 to antibiotic treatment under biofilm conditions. Finally, disruption of pathogenicity mechanisms was also assessed in vivo, with significantly increased survival of challenged larvae in a Galleria mellonella infection model. Favorable physicochemical properties and effects on virulence/biofilm establish a promising starting point for further optimization. In particular, the ability to address two targets of the PQS autoinduction cycle at the same time with a single compound holds great promise in achieving enhanced synergistic cellular effects while potentially lowering rates of resistance development.