Non-BRAF Mutant Melanoma: Molecular Features and Therapeutical Implications

Melanoma is one of the most aggressive tumors of the skin, and its incidence is growing worldwide. Historically considered a drug resistant disease, since 2011 the therapeutic landscape of melanoma has radically changed. Indeed, the improved knowledge of the immune system and its interactions with the tumor, and the ever more thorough molecular characterization of the disease, has allowed the development of immunotherapy on the one hand, and molecular target therapies on the other. The increased availability of more performing technologies like Next-Generation Sequencing (NGS), and the availability of increasingly large genetic panels, allows the identification of several potential therapeutic targets. In light of this, numerous clinical and preclinical trials are ongoing, to identify new molecular targets. Here, we review the landscape of mutated non-BRAF skin melanoma, in light of recent data deriving from Whole-Exome Sequencing (WES) or Whole-Genome Sequencing (WGS) studies on melanoma cohorts for which information on the mutation rate of each gene was available, for a total of 10 NGS studies and 992 samples, focusing on available, or in experimentation, targeted therapies beyond those targeting mutated BRAF. Namely, we describe 33 established and candidate driver genes altered with frequency greater than 1.5%, and the current status of targeted therapy for each gene. Only 1.1% of the samples showed no coding mutations, whereas 30% showed at least one mutation in the RAS genes (mostly NRAS) and 70% showed mutations outside of the RAS genes, suggesting potential new roads for targeted therapy. Ongoing clinical trials are available for 33.3% of the most frequently altered genes.

Successful treatment with imatinib after nilotinib and ipilimumab in a c-kit-mutated advanced melanoma patient: a case report

Treatment of melanoma remains a challenge in advanced disease. Recently, the molecular differentiation in BRAF-mutated, NRAS-mutated and c-kit-mutated melanomas led to new treatment strategies. Different trials show that imatinib or nilotinib lead to meaningful responses in c-kit-mutated melanoma patients. There are little published data on sequential inhibition using these two drugs in melanoma. We describe the sequential use of imatinib after nilotinib in a c-kit-mutated melanoma patient, who progressed on interferon, Allovectin, dacarbazine, nilotinib and ipilimumab, and was finally treated with the c-kit inhibitor imatinib. From July 2011 to September 2011, the patient received ipilimumab (four doses with 3 mg/kg). Clinical assessment after immunotherapy showed disease progression. Therefore, a treatment change to imatinib 800 mg daily was made from February 2012 to May 2013. Under this treatment, the patient showed a partial response as per the RECIST criteria. The present lesions continued responding (computed tomography scans: May 2012-March 2013). Unfortunately, in October 2012, new brain metastases developed. Nevertheless, the use of c-kit inhibitors in c-kit-mutated melanoma patients seems to be a promising treatment option. Furthermore, a delayed response to ipilimumab after 6 months could also have led to or supported the partial response in this case. However, when two biologically similar compounds are administered in a melanoma patient and the tumour mass shows progressive disease upon administration of the first agent, an additional progression with no effect may be expected when the second one is used. This case shows, in contrast, that the use of imatinib after progression upon nilotinib can be beneficial.

Multicenter, real-life experience with checkpoint inhibitors and targeted therapy agents in advanced melanoma patients in Switzerland

Metastatic melanoma is a highly aggressive disease. Recent progress in immunotherapy (IT) and targeted therapy (TT) has led to significant improvements in response and survival rates in metastatic melanoma patients. The current project aims to determine the benefit of the introduction of these new therapies in advanced melanoma across several regions of Switzerland. This is a retrospective multicenter analysis of 395 advanced melanoma patients treated with standard chemotherapy, checkpoint inhibitors, and kinase inhibitors from January 2008 until December 2014. The 1-year survival was 69% (n=121) in patients treated with checkpoint inhibitors (IT), 50% in patients treated with TTs (n=113), 85% in the IT+TT group (n=66), and 38% in patients treated with standard chemotherapy (n=95). The median overall survival (mOS) from first systemic treatment in the entire study cohort was 16.9 months. mOS of patients treated either with checkpoint or kinase inhibitors (n=300, 14.6 months) between 2008 and 2014 was significantly improved (P<0.0001) compared with patients treated with standard chemotherapy in 2008–2009 (n=95, 7.4 months). mOS of 61 patients with brain metastases at stage IV was 8.1 versus 12.5 months for patients without at stage IV (n=334), therefore being significantly different (P=0.00065). Furthermore, a significant reduction in hospitalization duration compared with chemotherapy was noted. Treatment with checkpoint and kinase inhibitors beyond clinical trials significantly improves the mOS in real life and the results are consistent with published prospective trial data.

Selumetinib in Combination With Dacarbazine in Patients With Metastatic Uveal Melanoma: A Phase III, Multicenter, Randomized Trial (SUMIT)

Purpose Uveal melanoma is the most common primary intraocular malignancy in adults with no effective systemic treatment option in the metastatic setting. Selumetinib (AZD6244, ARRY-142886) is an oral, potent, and selective MEK1/2 inhibitor with a short half-life, which demonstrated single-agent activity in patients with metastatic uveal melanoma in a randomized phase II trial. Methods The Selumetinib (AZD6244: ARRY-142886) (Hyd-Sulfate) in Metastatic Uveal Melanoma (SUMIT) study was a phase III, double-blind trial ( ClinicalTrial.gov identifier: NCT01974752) in which patients with metastatic uveal melanoma and no prior systemic therapy were randomly assigned (3:1) to selumetinib (75 mg twice daily) plus dacarbazine (1,000 mg/m2 intravenously on day 1 of every 21-day cycle) or placebo plus dacarbazine. The primary end point was progression-free survival (PFS) by blinded independent central radiologic review. Secondary end points included overall survival and objective response rate. Results A total of 129 patients were randomly assigned to receive selumetinib plus dacarbazine (n = 97) or placebo plus dacarbazine (n = 32). In the selumetinib plus dacarbazine group, 82 patients (85%) experienced a PFS event, compared with 24 (75%) in the placebo plus dacarbazine group (median, 2.8 v 1.8 months); the hazard ratio for PFS was 0.78 (95% CI, 0.48 to 1.27; two-sided P = .32). The objective response rate was 3% with selumetinib plus dacarbazine and 0% with placebo plus dacarbazine (two-sided P = .36). At 37% maturity (n = 48 deaths), analysis of overall survival gave a hazard ratio of 0.75 (95% CI, 0.39 to 1.46; two-sided P = .40). The most frequently reported adverse events (selumetinib plus dacarbazine v placebo plus dacarbazine) were nausea (62% v 19%), rash (57% v 6%), fatigue (44% v 47%), diarrhea (44% v 22%), and peripheral edema (43% v 6%). Conclusion In patients with metastatic uveal melanoma, the combination of selumetinib plus dacarbazine had a tolerable safety profile but did not significantly improve PFS compared with placebo plus dacarbazine.

Contemporary Treatment Approaches to Sinonasal Mucosal Melanoma

Sinonasal mucosal melanoma (SNMM) is a rare oncological entity that comprises most head and neck mucosal melanomas. SNMM has distinctive genetic background, different from cutaneous melanoma. Survival outcomes among SNMM patients are poor; while there is no clear consensus on the optimal management of SNMM, the primary treatment modality is generally considered to be wide surgical excision, and radiation therapy (RT) is often used in the postoperative adjuvant setting to improve locoregional control. Systemic therapies have demonstrated little or no survival benefit, and most SNMM patients die of distant metastatic disease. Owing to the rarity of the disease, the literature describing treatment approaches for SNMM is lacking and largely limited to isolated case reports and retrospective series. Here, we describe contemporary diagnostic and therapeutic approaches to SNMM based on the most recent molecular and outcome data.

Treatment of advanced melanoma - A changing landscape

Following decades of relative ostracism, advances in the treatment of melanoma have brought a new reality for patients, physicians and researchers. While antibodies targeting molecules involved in the modulation of the interaction between melanoma and immune cells changed the meaning of the term "cancer immunotherapy," a better characterization of the molecular aberrations involved in melanoma carcinogenesis prompted the development of inhibitors of the mitogen-activated protein kinase pathway (MAPK) that also led to significant improvements both in response rates and survival. As a result, new drugs have been approved for clinical use in the United States and Europe, including the immune-checkpoint blockers ipilmumab, pembrolizumab and nivolumab, the oncolytic herpesvirus talimogene laherparepvec, and the targeted-agents vemurafenib, dabrafenib, cobimetinib and trametinib. In this article, we review the results of studies that brought new approaches to the bedside and discuss how these developments are being incorporated into the care of patients in Brazil.

MEK Inhibitors in the Treatment of Metastatic Melanoma and Solid Tumors

The mitogen-activated protein kinase (MAPK) cascade is an intracellular signaling pathway involved in the regulation of cellular proliferation and the survival of tumor cells. Several different mutations, involving BRAF or NRAS, exert an oncogenic effect by activating the MAPK pathway, resulting in an increase in cellular proliferation. These mutations have become targets for new therapeutic strategies in melanoma and other cancers. Selective MEK inhibitors have the ability to inhibit growth and induce cell death in BRAF- and NRAS-mutant melanoma cell lines. MEK inhibitor therapy in combination with a BRAF inhibitor is more effective and less toxic than treatment with a BRAF inhibitor alone, and has become the standard of care for patients with BRAF-mutated melanoma. Trametinib was the first MEK inhibitor approved for the treatment of BRAF-mutated metastatic melanoma not previously treated with BRAF inhibitors, and is also approved in combination with the BRAF inhibitor dabrafenib. Furthermore, cobimetinib is another MEK inhibitor approved for the treatment of BRAF-mutated metastatic melanoma in combination with a BRAF inhibitor, vemurafenib. The MEK inhibitor binimetinib in combination with the BRAF inhibitor encorafenib is in clinical development. The addition of an anti-PD-1/PD-L1 agent, such as pembrolizumab, durvalumab or atezolizumab, to combined BRAF and MEK inhibition has shown considerable promise, with several trials ongoing in metastatic melanoma. Binimetinib has also shown efficacy in NRAS-mutated melanoma patients. Future possibilities for MEK inhibitors in advanced melanoma, as well as other solid tumors, include their use in combination with other targeted therapies (e.g. anti-CDK4/6 inhibitors) and/or various immune-modulating antibodies.

Exploiting Drug Addiction Mechanisms to Select against MAPKi-Resistant Melanoma

Melanoma resistant to MAPK inhibitors (MAPKi) displays loss of fitness upon experimental MAPKi withdrawal and, clinically, may be resensitized to MAPKi therapy after a drug holiday. Here, we uncovered and therapeutically exploited the mechanisms of MAPKi addiction in MAPKi-resistant BRAF^MUT or NRAS^MUT melanoma. MAPKi-addiction phenotypes evident upon drug withdrawal spanned transient cell-cycle slowdown to cell-death responses, the latter of which required a robust phosphorylated ERK (pERK) rebound. Generally, drug withdrawal-induced pERK rebound upregulated p38-FRA1-JUNB-CDKN1A and downregulated proliferation, but only a robust pERK rebound resulted in DNA damage and parthanatos-related cell death. Importantly, pharmacologically impairing DNA damage repair during MAPKi withdrawal augmented MAPKi addiction across the board by converting a cell-cycle deceleration to a caspase-dependent cell-death response or by furthering parthanatos-related cell death. Specifically in MEKi-resistant NRAS^MUT or atypical BRAF^MUT melanoma, treatment with a type I RAF inhibitor intensified pERK rebound elicited by MEKi withdrawal, thereby promoting a cell death-predominant MAPKi-addiction phenotype. Thus, MAPKi discontinuation upon disease progression should be coupled with specific strategies that augment MAPKi addiction.Significance: Discontinuing targeted therapy may select against drug-resistant tumor clones, but drug-addiction mechanisms are ill-defined. Using melanoma resistant to but withdrawn from MAPKi, we defined a synthetic lethality between supraphysiologic levels of pERK and DNA damage. Actively promoting this synthetic lethality could rationalize sequential/rotational regimens that address evolving vulnerabilities. Cancer Discov; 8(1); 74-93. ©2017 AACR.See related commentary by Stern, p. 20This article is highlighted in the In This Issue feature, p. 1.

Targeted Therapies in Combination With Immune Therapies for the Treatment of Metastatic Melanoma

In recent years, the field of oncology has witnessed many breakthroughs in the treatment of advanced malignancies, particularly in patients with advanced melanoma. Targeted and immune checkpoint therapies have emerged as the primary treatment strategies for these patients. Molecular profiling of melanoma is incorporated into routine practice to identify potential therapeutic targets, and patients are offered either a targeted or immune checkpoint inhibitor therapy approach. Both strategies have limitations where not all patients experience durable responses. Preclinical data have demonstrated the ability of targeted therapy to enhance activity of effector T cells, reduce immunosuppressive cytokine production, and increase tumor cell antigen presentation, which can augment antitumor immunity. In vivo models have shown synergy with improved tumor control when targeted and immune checkpoint agents are combined. Therefore, combination strategies with targeted and immune checkpoint therapy may improve patient outcomes. Early clinical data with anti-programmed cell-death protein 1/programmed cell-death ligand 1 agents in combination with targeted inhibitors appear to have acceptable toxicity rates and the potential for enhanced antitumor activity. This review explores the current status of preclinical and clinical development for these combination approaches in patients with advanced melanoma.

Novel Targeted Therapies for Metastatic Melanoma

Oncogene-targeted therapy is a major component of precision oncology, and although patients with metastatic melanoma have experienced improved outcomes with this strategy, there are a number of potential therapeutic targets currently under study that may further increase the drug armamentarium for this patient population. In this review, we discuss the landscape of targeted therapies for patients with advanced melanoma, focusing on oncogene mutation-specific targets. In patients with typical BRAF V600-mutant melanoma, combination BRAF and MEK inhibition has surpassed outcomes compared with monotherapy with BRAF or MEK inhibition alone, and current strategies seek to address inevitable resistance mechanisms. For patients with NRAS-mutant melanoma, MEK inhibitor monotherapy and combined MEK and CDK4/6 inhibition are burgeoning strategies; for patients with KIT-mutant melanoma, tyrosine kinase inhibition is being leveraged, and for NF-1-mutant melanoma, mTOR and MEK inhibition is being actively evaluated. In patients with atypical, non-V600 BRAF-mutant melanoma, MEK inhibitor monotherapy is the potential novel targeted approach on the horizon. For advanced uveal melanoma, novel targets such as IMCgp100 and glembatumumab have shown activity in early studies. We review additional strategies that remain in the preclinical and early clinical pipeline, so there is much hope for the future of targeted agents for distinct molecular cohorts of patients with advanced melanoma.

Variation of mutant allele frequency in NRAS Q61 mutated melanomas

BACKGROUND

Somatic mutations of BRAF or NRAS activating the MAP kinase cell signaling pathway are present in 70% of cutaneous melanomas. The mutant allele frequency of BRAF V600E (M%BRAF) was recently shown to be highly heterogeneous in melanomas. The present study focuses on the NRAS Q61 mutant allele frequency (M%NRAS).

METHODS

Retrospective quantitative analyze of 104 NRAS mutated melanomas was performed using pyrosequencing. Mechanisms of M%NRAS imbalance were studied by fluorescence in situ hybridization (FISH) and microsatellite analysis.

RESULTS

M%NRAS was increased in 27.9% of cases. FISH revealed that chromosome 1 instability was the predominant mechanism of M%NRAS increase, with chromosome 1 polysomy observed in 28.6% of cases and intra-tumor cellular heterogeneity with copy number variations of chromosome 1/NRAS in 23.8%. Acquired copy-neutral loss of heterozygosity (LOH) was less frequent (19%). However, most samples with high M%NRAS had only one copy of NRAS locus surrounding regions suggesting a WT allele loss. Clinical characteristics and survival of patients with either <60% or ≥60% of M%NRAS were not different.

CONCLUSION

As recently shown for M%BRAF, M%NRAS is highly heterogeneous. The clinical impacts of high M%NRAS should be investigated in a larger series of patients.

Mutation status among patients with sinonasal mucosal melanoma and its impact on survival

BACKGROUND

Sinonasal mucosal melanoma (SNMM) comprises <1% of all melanomas and lacks well-characterised molecular markers. Our aim was to determine the frequencies of common mutations and examine their utility as molecular markers in a large series of primary SNMMs.

METHODS

SNMM patients seen at our institution from August 1991 through July 2016 were identified. Genomic DNA was extracted from 66 formalin-fixed paraffin-embedded tumours and screened for mutations by direct sequencing. We investigated the association of mutations with clinicopathological features and survival outcomes.

RESULTS

Overall, 41% (27 out of 66) of the SNMMs harboured mutations. BRAF and KIT mutations were identified in 8% (five patients) and 5% (three patients) of SNMMs, respectively, whereas NRAS mutations were detected in 30% (20 patients) of SNMMs. Mutation rates in these oncogenes were similar between SNMMs located in the paranasal sinuses and those in the nasal cavity (30% and 13%, respectively, P=0.09). In a multivariate analysis, patients with negative margins had significantly better overall survival (hazard ratio 5.43, 95% confidence interval 1.44-21.85, P=0.01) and disease-specific survival (hazard ratio 21.9, 95% confidence interval 3.71-180, P=0.0004). The mutation status of the tumours showed no association with survival outcomes.

CONCLUSIONS

In SNNM, mutation status does not affect survival outcomes, but NRAS mutations are relatively frequent and could be targeted in this disease by MEK inhibitors.

Treatment of NRAS-mutated advanced or metastatic melanoma: rationale, current trials and evidence to date

The disease course of BRAF (v-raf murine sarcoma viral oncogene homolog B1)-mutant melanoma has been drastically improved by the arrival of targeted therapies. NRAS (neuroblastoma RAS viral oncogene homolog)-mutated melanoma represents 15–25% of all metastatic melanoma patients. It currently does not have an approved targeted therapy. Metastatic patients receive immune-based therapies as first-line treatments, then cytotoxic chemotherapy like carboplatin/paclitaxel (C/P), dacarbazine (DTIC) or temozolomide (TMZ) as a second-line treatment. We will review current preclinical and clinical developments in NRAS-mutated melanoma, and analyze ongoing clinical trials that are evaluating the benefit of different targeted and immune-based therapies, either tested as single agents or in combination, in NRAS-mutant melanoma.

A systematic review and network meta-analysis of immunotherapy and targeted therapy for advanced melanoma

Immune and BRAF‐targeted therapies have changed the therapeutic scenario of advanced melanoma, turning the clinical decision‐making a challenging task. This Bayesian network meta‐analysis assesses the role of immunotherapies and targeted therapies for advanced melanoma. We retrieved randomized controlled trials testing immune, BRAF‐ or MEK‐targeted therapies for advanced melanoma from electronic databases. A Bayesian network model compared therapies using hazard ratio (HR) for overall survival (OS), progression‐free survival (PFS), and odds ratio (OR) for response rate (RR), along with 95% credible intervals (95% CrI), and probabilities of drugs outperforming others. We assessed the impact of PD‐L1 expression on immunotherapy efficacy. Sixteen studies evaluating eight therapies in 6849 patients were analyzed. For OS, BRAF‐MEK combination and PD‐1 single agent ranked similarly and outperformed all other treatments. For PFS, BRAF‐MEK combination surpassed all other options, including CTLA‐4‐PD‐1 dual blockade hazard ratio (HR: 0.56; 95% CrI: 0.33–0.97; probability better 96.2%), whereas BRAF single agent ranked close to CTLA‐4‐PD‐1 blockade. For RR, BRAF‐MEK combination was superior to all treatments including CTLA‐4‐PD‐1 (OR: 2.78; 1.18–6.30; probability better 97.1%). No OS data were available for CTLA‐4‐PD‐1 blockade at the time of systematic review, although PFS and RR results suggested that this combination could also bring meaningful benefit. PD‐L1 expression, as presently defined, failed to inform patient selection to PD‐1‐based immunotherapy. BRAF‐MEK combination seemed an optimal therapy for BRAF‐mutated patients, whereas PD‐1 inhibitors seemed optimal for BRAF wild‐type patients. Longer follow‐up is needed to ascertain the role of CTLA‐4‐PD‐1 blockade. Immunotherapy biomarkers remain as an unmet need.

Targeted agents and immunotherapies: optimizing outcomes in melanoma

Treatment options for patients with metastatic melanoma, and especially BRAF-mutant melanoma, have changed dramatically in the past 5 years, with the FDA approval of eight new therapeutic agents. During this period, the treatment paradigm for BRAF-mutant disease has evolved rapidly: the standard-of-care BRAF-targeted approach has shifted from single-agent BRAF inhibition to combination therapy with a BRAF and a MEK inhibitor. Concurrently, immunotherapy has transitioned from cytokine-based treatment to antibody-mediated blockade of the cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) and, now, the programmed cell-death protein 1 (PD-1) immune checkpoints. These changes in the treatment landscape have dramatically improved patient outcomes, with the median overall survival of patients with advanced-stage melanoma increasing from approximately 9 months before 2011 to at least 2 years - and probably longer for those with BRAF-V600-mutant disease. Herein, we review the clinical trial data that established the standard-of-care treatment approaches for advanced-stage melanoma. Mechanisms of resistance and biomarkers of response to BRAF-targeted treatments and immunotherapies are discussed, and the contrasting clinical benefits and limitations of these therapies are explored. We summarize the state of the field and outline a rational approach to frontline-treatment selection for each individual patient with BRAF-mutant melanoma.

Digoxin Plus Trametinib Therapy Achieves Disease Control in BRAF Wild-Type Metastatic Melanoma Patients

This is the first prospective study of a combination therapy involving a cardenolide and a MEK inhibitor for metastatic melanoma. Whereas BRAF mutant melanomas can exhibit profound responses to treatment with BRAF and MEK inhibitors, there are fewer options for BRAF wild-type melanomas. In preclinical studies, we discovered that cardenolides synergize with MEK inhibitor to promote the regression of patient-derived xenografts irrespective of BRAF mutation status. We therefore conducted a phase 1B study of digoxin 0.25 mg and trametinib 2 mg given orally once daily in 20 patients with advanced, refractory, BRAF wild-type melanomas. The most common adverse events were rash, diarrhea, nausea, and fatigue. The response rate was 4/20 or 20% with response durations of 2, 4, 6, and 8 months. The disease control rate (including partial responses and stable disease) was 13/20 or 65% of patients, including 5/6 or 83% of patients with NRAS mutant melanomas and 8/14 or 57% of NRAS wild-type melanomas. Patients with stable disease had disease control for 2, 2, 2, 4, 5, 6, 7, 10, and 10 months. Xenografts from four patients recapitulated the treatment responses observed in patients. Based on these pilot results, an expansion arm of digoxin plus MEK inhibitor is warranted for NRAS mutant metastatic melanoma patients who are refractory or intolerant of immunotherapy.

KEY POINTS

Digoxin plus trametinib is well tolerated and achieves a high rate of disease control in BRAF wild-type metastatic melanoma patients.

Can binimetinib, encorafenib and masitinib be more efficacious than currently available mutation-based targeted therapies for melanoma treatment?

INTRODUCTION

Historically, there were few effective and durable treatments for metastatic melanoma. Recently, mutation based targeted therapies have revolutionized treatment and outcomes for patients with metastatic melanoma. Specifically, inhibitors aimed at BRAF, NRAS, and C-KIT mutations are now commonly used in treatment for patients harboring the specific mutations. Areas covered: A brief review of current BRAF, NRAS, and C-KIT inhibitors provides background for a thorough review of newly developed agents namely binimetinib, a MEK inhibitor, encorafenib a BRAF inhibitor, and masitinib which inhibits C-KIT. Expert opinion: While the 3 novel agents reviewed here have potential for use in melanoma, optimal utilization will occur once a more personalized approach incorporating genomic, proteomic, and immunologic data guides therapeutic decisions.

A phase 1 dose-escalation and expansion study of binimetinib (MEK162), a potent and selective oral MEK1/2 inhibitor

BACKGROUND

Binimetinib (MEK162; ARRY-438162) is a potent and selective oral MEK 1/2 inhibitor. This phase 1 study determined the maximum tolerated dose (MTD), safety, pharmacokinetic and pharmacodynamic profiles, and preliminary anti-tumour activity of binimetinib in patients with advanced solid tumours, with expansion cohorts of patients with biliary cancer or KRAS- or BRAF-mutant colorectal cancer.

METHODS

Binimetinib was administered twice daily. Expansion cohorts were enroled after MTD determination following a 3+3 dose-escalation design. Pharmacokinetic properties were determined from plasma samples. Tumour samples were assessed for mutations in RAS, RAF, and other relevant genes. Pharmacodynamic properties were evaluated in serum and skin punch biopsy samples.

RESULTS

Ninety-three patients received binimetinib (dose-escalation phase, 19; expansion, 74). The MTD was 60 mg twice daily, with dose-limiting adverse events (AEs) of dermatitis acneiform and chorioretinopathy. The dose for expansion patients was subsequently decreased to 45 mg twice daily because of the frequency of treatment-related ocular toxicity at the MTD. Common AEs across all dose levels included rash (81%), nausea (56%), vomiting (52%), diarrhoea (51%), peripheral oedema (46%), and fatigue (43%); most were grade 1/2. Dose-proportional increases in binimetinib exposure were observed and target inhibition was demonstrated in serum and skin punch biopsy samples. Three patients with biliary cancer had objective responses (one complete and two partial).

CONCLUSIONS

Binimetinib demonstrated a manageable safety profile, target inhibition, and dose-proportional exposure. The 45 mg twice daily dose was identified as the recommended phase 2 dose. The three objective responses in biliary cancer patients are encouraging and support further evaluation in this population.

Novel melanoma therapy

With the rapid succession of new effective agents for melanoma in the recent years, the paradigm for treatment of metastatic melanoma is changing. The success of combining multiple effective agents compared with outcomes of monotherapy also brings increasing complexity in the treatment algorithm for various subsets of metastatic melanoma patients. We reviewed the recent reports on novel melanoma therapy to shed light on rational decision-making in treating these patients.