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

Targeted therapies and immune checkpoint inhibitors in the treatment of metastatic melanoma patients: a guide and update for pathologists

The previously dismal prospects for patients with advanced stage metastatic melanoma have greatly improved in recent years. Enhanced understanding of both the pathogenesis of melanoma and its molecular drivers, as well as the importance and regulation of anti-tumour immune responses, have provided new therapeutic opportunities for melanoma patients. There are two major distinct categories of systemic treatments with activity for patients with metastatic melanoma: (1) targeted therapies, which act to inhibit the oncogenes that drive the aberrant growth and dissemination of the tumour; and (2) immune checkpoint inhibitor therapies, which act to enhance anti-tumour immune responses by blocking negative regulators of immunity. Pathologists play a critical and expanding role in the selection of the most appropriate treatment for individual metastatic melanoma patients in the modern era of personalised/precision medicine. The molecular pathology testing of melanoma tumour tissue for the presence of targetable oncogenic mutations is already part of routine practice in many institutions. In addition, other potential oncogenic therapeutic targets continue to be identified and pathology testing techniques must readily adapt to this rapidly changing field. Recent research findings suggest that pathological assessment of tumour associated immune cells and immunosuppressive ligand expression of the tumour are likely to be important in identifying patients most likely to benefit from immune checkpoint inhibitors. Similarly, pathological and molecular observations of on-treatment tumour tissue biopsies taken from patients on targeted therapies have provided new insights into the mechanisms of action of targeted molecular therapies, have contributed to the identification of resistance mechanisms to these novel therapies and may be of higher value for selecting patients most likely to benefit from therapies. These data have already provided a rational biological basis for the exciting prospect of combining them to further improve survival rates and this is currently being investigated in clinical trials. Ultimately it may be the responsibility of the pathologist to identify which therapy or combination of therapies is most likely to benefit individual patients.

Renal effects of BRAF inhibitors: a systematic review by the Cancer and the Kidney International Network

Advanced melanoma has been traditionally unresponsive to standard chemotherapy agents and used to have a dismal prognosis. Genetically targeted small-molecule inhibitors of the oncogenic BRAF V600 mutation or a downstream signaling partner (MEK mitogen-activated protein kinase) are effective treatment options for the 40–50% of melanomas that harbor mutations in BRAF. Selective BRAF and MEK inhibitors induce frequent and dramatic objective responses and markedly improve survival compared with cytotoxic chemotherapy. In the past decade after discovery of this mutation, drugs such as vemurafenib and dabrafenib have been approved by the US Food and Drug Administration (FDA) and the European Medicines Agency for the treatment of V600-mutated melanomas. While the initial trials did not signal any renal toxicities with the BRAF inhibitors, recent case reports, case series and FDA adverse reporting systems have uncovered significant nephrotoxicities with these agents. In this article, we systematically review the nephrotoxicities of these agents. Based on recently published data, it appears that there are lower rates of kidney disease and cutaneous lesions seen with dabrafenib compared with vemurafenib. The pathology reported in the few kidney biopsies done so far are suggestive of tubulo interstitial damage with an acute and chronic component. Electrolyte disorders such as hypokalemia, hyponatremia and hypophosphatemia have been reported as well. Routine monitoring of serum creatinine and electrolytes and calculation of glomerular filtration rate prior to the first administration when treating with dabrafenib and vemurafenib are essential.

Melanoma: the intersection of molecular targeted therapy and immune checkpoint inhibition

Melanoma is at the forefront of development of systemic therapeutics with both molecular targeted therapies and immune checkpoint inhibitors as cornerstones of treatment. Although responses to molecularly targeted therapy is largely from blockade of oncogenic pathways, evidence is emerging of the immunomodulatory effects from BRAF inhibition. Additionally programmed-death-1 (PD-1) inhibitors have revolutionized the treatment of melanoma and are set to pave future improvements in other solid tumors. Combinations of PD-1 inhibitors with novel immune checkpoints or with molecularly targeted therapies are under investigation and may improve on the considerable progress made.

Radiotherapy with BRAF inhibitor therapy for melanoma: progress and possibilities

The introduction of small molecule BRAFV600 kinase inhibitors represents a milestone in the targeted therapy of patients with metastatic melanoma by a significant increase in therapeutic efficacy in terms of overall and progression-free survival compared with conventional chemotherapy. Beside BRAFV600 inhibitor treatment, radiotherapy is a further mainstay for the therapy of metastatic melanoma and thus a concomitant or sequential application of BRAFV600 inhibitors and radiotherapy is inevitable. Recent reports show a significant radiosensitization of the irradiated healthy tissue in patients with melanoma after the combination of radiotherapy and BRAFV600 inhibitors, evoking concern in clinical practice. We review interactions of BRAFV600 inhibitors and radiation with regard to antitumor effects and an increased radiotoxicity in the healthy tissue.

Combination therapy with BRAF and MEK inhibitors for melanoma: latest evidence and place in therapy

Treatment with BRAF inhibitors such as vemurafenib or dabrafenib in patients with advanced BRAFV600 mutated melanoma has shown objective tumor responses in approximately half of the patients. However, the duration of responses is limited in a majority of these patients, with progression-free survival rates around 6 months due to tumor progression from development of acquired resistance. Preclinical studies have suggested that concurrent inhibition of the BRAF kinases and MEK of the mitogen-activated protein kinase (MAPK) pathway could decrease MAPK-driven acquired resistance, resulting in longer duration of responses, higher rate of tumor responses, and a decrease in the cutaneous toxicities observed from paradoxical MAPK pathway activation with BRAF inhibitor monotherapy. This review provides an overview of the currently available clinical trial data on BRAF and MEK inhibitors together and in combinations with other therapeutic agents.

Survival of patients with advanced metastatic melanoma: The impact of novel therapies

The survival of advanced metastatic melanoma has been greatly improved within the past few years. New therapeutic strategies like kinase inhibitors for BRAF-mutant melanoma and immune checkpoint blockers proved to prolong survival times within clinical trials, and many of them have already entered routine clinical use. However, these different treatment modalities have not yet been tested against each other, which complicate therapy decisions. We performed an explorative analysis of survival data from recent clinical trials. Thirty-five Kaplan-Meier survival curves from 17 trials were digitised, re-grouped by matching inclusion criteria and treatment line, and averaged by therapy strategy. Notably, the survival curves grouped by therapy strategy revealed a very high concordance, even if different agents were used. The greatest survival improvement was observed with the combination of BRAF plus MEK inhibitors as well as with Programmed-death-1 (PD1) blockers with or without cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) blockers, respectively, with these two treatment strategies showing similar survival outcomes. For first-line therapy, averaged survival proportions of patients alive at 12 months were 74.5% with BRAF plus MEK inhibitor treatment versus 71.9% with PD-1 blockade. This explorative comparison shows the kinase inhibitors as similarly effective as immune checkpoint blockers with regard to survival. However, to confirm these first trends for implementation into an individualised treatment of melanoma patients, data from prospective clinical trials comparing the different treatment strategies head-to-head have to be awaited.

Targeting oncogenic BRAF and aberrant MAPK activation in the treatment of cutaneous melanoma

BRAF and MEK inhibitors, alone or in combination, are highly active in the 40% of patients with BRAF mutant metastatic melanoma. Despite this activity resistance often develops in patients treated with these agents. This review summarises the biology of the mitogen activated protein kinase (MAPK) pathway, with particular reference to the effects of BRAF and MEK inhibitors in BRAF mutant melanoma. The clinical and molecular predictors of response and mechanisms of resistance are discussed in detail along with the biological rationale and evidence for future treatment strategies in both MAPK inhibitor naïve and resistant BRAF mutant melanoma.

Future perspectives in melanoma research: meeting report from the "Melanoma Bridge": Napoli, December 3rd-6th 2014

The fourth "Melanoma Bridge Meeting" took place in Naples, December 3-6th, 2014. The four topics discussed at this meeting were: Molecular and Immunological Advances, Combination Therapies, News in Immunotherapy, and Tumor Microenvironment and Biomarkers. Until recently systemic therapy for metastatic melanoma patients was ineffective, but recent advances in tumor biology and immunology have led to the development of new targeted and immunotherapeutic agents that prolong progression-free survival (PFS) and overall survival (OS). New therapies, such as mitogen-activated protein kinase (MAPK) pathway inhibitors as well as other signaling pathway inhibitors, are being tested in patients with metastatic melanoma either as monotherapy or in combination, and all have yielded promising results. These include inhibitors of receptor tyrosine kinases (BRAF, MEK, and VEGFR), the phosphatidylinositol 3 kinase (PI3K) pathway [PI3K, AKT, mammalian target of rapamycin (mTOR)], activators of apoptotic pathway, and the cell cycle inhibitors (CDK4/6). Various locoregional interventions including radiotherapy and surgery are still valid approaches in treatment of advanced melanoma that can be integrated with novel therapies. Intrinsic, adaptive and acquired resistance occur with targeted therapy such as BRAF inhibitors, where most responses are short-lived. Given that the reactivation of the MAPK pathway through several distinct mechanisms is responsible for the majority of acquired resistance, it is logical to combine BRAF inhibitors with inhibitors of targets downstream in the MAPK pathway. For example, combination of BRAF/MEK inhibitors (e.g., dabrafenib/trametinib) have been demonstrated to improve survival compared to monotherapy. Application of novel technologies such sequencing have proven useful as a tool for identification of MAPK pathway-alternative resistance mechanism and designing other combinatorial therapies such as those between BRAF and AKT inhibitors. Improved survival rates have also been observed with immune-targeted therapy for patients with metastatic melanoma. Immune-modulating antibodies came to the forefront with anti-CTLA-4, programmed cell death-1 (PD-1) and PD-1 ligand 1 (PD-L1) pathway blocking antibodies that result in durable responses in a subset of melanoma patients. Agents targeting other immune inhibitory (e.g., Tim-3) or immune stimulating (e.g., CD137) receptors and other approaches such as adoptive cell transfer demonstrate clinical benefit in patients with melanoma as well. These agents are being studied in combination with targeted therapies in attempt to produce longer-term responses than those more typically seen with targeted therapy. Other combinations with cytotoxic chemotherapy and inhibitors of angiogenesis are changing the evolving landscape of therapeutic options and are being evaluated to prevent or delay resistance and to further improve survival rates for this patient population. This meeting's specific focus was on advances in combination of targeted therapy and immunotherapy. Both combination targeted therapy approaches and different immunotherapies were discussed. Similarly to the previous meetings, the importance of biomarkers for clinical application as markers for diagnosis, prognosis and prediction of treatment response was an integral part of the meeting. The overall emphasis on biomarkers supports novel concepts toward integrating biomarkers into contemporary clinical management of patients with melanoma across the entire spectrum of disease stage. Translation of the knowledge gained from the biology of tumor microenvironment across different tumors represents a bridge to impact on prognosis and response to therapy in melanoma.

Other targeted drugs in melanoma

Targeted therapy drugs are developed against specific molecular alterations on cancer cells. Because they are "targeted" to the tumor, these therapies are more effective and better tolerated than conventional therapies such as chemotherapy. In the last decade, great advances have been made in understanding of melanoma biology and identification of molecular mechanisms involved in malignant transformation of cells. The identification of oncogenic mutated kinases involved in this process provides an opportunity for development of new target therapies. The dependence of melanoma on BRAF-mutant kinase has provided an opportunity for development of mutation-specific inhibitors with high activity and excellent tolerance that are now being used in clinical practice. This marked a new era in the treatment of metastatic melanoma and much research is now ongoing to identify other "druggable" kinases and transduction signaling networking. It is expected that in the near future the spectrum of target drugs for melanoma treatment will increase. Herein, we review the most relevant potential novel drugs for melanoma treatment based on preclinical data and the results of early clinical trials.

Metastatic melanoma treatment: Combining old and new therapies

Metastatic melanoma is an aggressive form of cancer characterised by poor prognosis and a complex etiology. Until 2010, the treatment options for metastatic melanoma were very limited. Largely ineffective dacarbazine, temozolamide or fotemustine were the only agents in use for 35 years. In recent years, the development of molecularly targeted inhibitors in parallel with the development of checkpoint inhibition immunotherapies has rapidly improved the outcomes for metastatic melanoma patients. Despite these new therapies showing initial promise; resistance and poor duration of response have limited their effectiveness as monotherapies. Here we provide an overview of the history of melanoma treatment, as well as the current treatments in development. We also discuss the future of melanoma treatment as we go beyond monotherapies to a combinatorial approach. Combining older therapies with the new molecular and immunotherapies will be the most promising way forward for treatment of metastatic melanoma.

Pembrolizumab in the management of metastatic melanoma

Pembrolizumab is a humanized IgG4 anti-PD-1 antibody that plays a major role in the treatment of advanced melanoma. Through blockade of PD-1, it leads to an increase in effector T-cell activity in the tumor microenvironment. Clinical trial outcomes for pembrolizumab in addition to pharmacokinetics, pharmacodynamics and safety of the compound are discussed in this article. Phase I trials have demonstrated safety and efficacy of pembrolizumab in advanced, pretreated melanoma patients. When compared with chemotherapy in a Phase II trial of ipilimumab-refractory patients, those treated with pembrolizumab showed superior progression-free survival. In addition, in the pivotal Phase III trial pembrolizumab improved overall survival compared with ipilimumab in patients naive to immune checkpoint inhibition. Pembrolizumab is well tolerated and has a favorable safety profile. Common adverse events are fatigue, rash, itching and diarrhea. Less frequent immune-related adverse events include hypothyroidism, colitis, hepatitis and pneumonitis.

Hepatic hemorrhage as a consequence of rapid response to combined targeted therapy in metastatic melanoma

A middle-aged female with metastatic melanoma was found to have hemoperitoneum after starting systemic therapy with the BRAF and MEK inhibitors dabrafenib and trametinib. Etiology proved to be bleeding from a known hepatic metastasis. The patient was managed conservatively and eventually resumed systemic therapy with ongoing response. This case serves to illustrate the possible deleterious effects of rapid tumor response after initiation of targeted systemic therapy in patients with metastatic melanoma.

Preclinical Evidence That Trametinib Enhances the Response to Antiangiogenic Tyrosine Kinase Inhibitors in Renal Cell Carcinoma

Sunitinib and pazopanib are antiangiogenic tyrosine kinase inhibitors (TKI) used to treat metastatic renal cell carcinoma (RCC). However, the ability of these drugs to extend progression-free and overall survival in this patient population is limited by drug resistance. It is possible that treatment outcomes in RCC patients could be improved by rationally combining TKIs with other agents. Here, we address whether inhibition of the Ras-Raf-MEK-ERK1/2 pathway is a rational means to improve the response to TKIs in RCC. Using a xenograft model of RCC, we found that tumors that are resistant to sunitinib have a significantly increased angiogenic response compared with tumors that are sensitive to sunitinib in vivo. We also observed significantly increased levels of phosphorylated ERK1/2 in the vasculature of resistant tumors, when compared with sensitive tumors. These data suggested that the Ras-Raf-MEK-ERK1/2 pathway, an important driver of angiogenesis in endothelial cells, remains active in the vasculature of TKI-resistant tumors. Using an in vitro angiogenesis assay, we identified that the MEK inhibitor (MEKI) trametinib has potent antiangiogenic activity. We then show that, when trametinib is combined with a TKI in vivo, more effective suppression of tumor growth and tumor angiogenesis is achieved than when either drug is utilized alone. In conclusion, we provide preclinical evidence that combining a TKI, such as sunitinib or pazopanib, with a MEKI, such as trametinib, is a rational and efficacious treatment regimen for RCC.

Trametinib: a MEK inhibitor for management of metastatic melanoma

This review presents the current data on the efficacy and safety of the selective mitogen-activated extracellular signal-regulated kinase (MEK) inhibitor trametinib in patients with metastatic BRAF V600-positive melanoma. The pharmacological, safety, and efficacy data come from the Phase I, II, and III studies of trametinib monotherapy, as well as those in combination with the BRAF inhibitor dabrafenib. The most common adverse effects of trametinib therapy are rash, dermatitis, diarrhea, and fatigue. The Phase III METRIC study showed significant improvement in overall survival and progression-free survival in favor of trametinib over standard dacarbazine or paclitaxel chemotherapy. Therefore, trametinib was approved by the US Food and Drug Administration and European Medicines Agency as a single agent for the treatment of patients with V600E-mutated metastatic melanoma. Progression-free survival and response rates for trametinib monotherapy were lower than those noted with BRAF inhibitors. The second step in developing trametinib was to use the combination of trametinib with the BRAF inhibitor, eg, dabrafenib, to postpone the progression on MEK or BRAF inhibitors. The recently published data showed significant improvement in overall survival and progression-free survival in favor of the combination of trametinib and dabrafenib over vemurafenib therapy or dabrafenib alone, with good tolerance. The US Food and Drug Administration has approved the combination of dabrafenib (150 mg orally twice daily) and trametinib (2 mg orally once daily) for the treatment of patients with BRAF V600E/K-mutant metastatic melanoma, and their use seems to be currently the best approach. While BRAF-MEK inhibition is a standard, molecular targeted therapy in BRAF-mutated melanomas, its future utility has to be established in the rapidly changing landscape of immunotherapeutics.

The Role of Regional Therapies for in-Transit Melanoma in the Era of Improved Systemic Options

The incidence of melanoma has been increasing at a rapid rate, with 4%–11% of all melanoma recurrences presenting as in-transit disease. Treatments for in-transit melanoma of the extremity are varied and include surgical excision, lesional injection, regional techniques and systemic therapies. Excision to clear margins is preferred; however, in cases of widespread disease, this may not be practical. Historically, intralesional therapies were generally not curative and were often used for palliation or as adjuncts to other therapies, but recent advances in oncolytic viruses may change this paradigm. Radiation as a regional therapy can be quite locally toxic and is typically relegated to disease control and symptom relief in patients with limited treatment options. Regional therapies such as isolated limb perfusion and isolated limb infusion are older therapies, but offer the ability to treat bulky disease for curative intent with a high response rate. These techniques have their associated toxicities and can be technically challenging. Historically, systemic therapy with chemotherapies and biochemotherapies were relatively ineffective and highly toxic. With the advent of novel immunotherapeutic and targeted small molecule agents for the treatment of metastatic melanoma, the armamentarium against in-transit disease has expanded. Given the multitude of options, many different combinations and sequences of therapies can be offered to patients with in-transit extremity melanoma in the contemporary era. Reported response and survival rates of the varied treatments may offer valuable information regarding treatment decisions for patients with in-transit melanoma and provide rationale for these decisions.

Cancer Genomics

Modern cancer genomics has emerged from the combination of the Human Genome Reference, massively parallel sequencing, and the comparison of tumor to normal DNA sequences, revealing novel insights into the cancer genome and its amazing diversity. Recent developments in applying our knowledge of cancer genomics have focused on the utility of these data for clinical applications. The emergent results of this translation into the clinical setting already are changing the clinical care and monitoring of cancer patients.