Doublet BRAF/MEK inhibition versus single-agent BRAF inhibition in the management of BRAF-mutant advanced melanoma, biological rationale and meta-analysis of published data

Potential drug-drug interactions with mitogen-activated protein kinase (MEK) inhibitors used to treat melanoma

INTRODUCTION

The management of patients with BRAF-mutated advanced melanoma who are undergoing targeted therapy with MEK inhibitors can be complicated by the co-administration of multiple medications, which can give rise to drug-drug interactions of clinical significance.

COVERED AREAS

Our review presents a comprehensive analysis of the pharmacokinetic and pharmacodynamic interactions of the three approved for advanced melanoma MEK inhibitor drugs - binimetinib, cobimetinib, and trametinib. MEDLINE (PubMed) was utilized for the literature search, comprising clinical studies, observational studies, and preclinical research. The review discusses the impact of these interactions on efficacy and safety of the treatments and differentiates between interactions supported by pharmacokinetic or pharmacodynamic mechanisms, those encountered in clinical practice, and those observed in preclinical studies.

EXPERT OPINION

Physicians should be aware about potential benefits, but also increased toxicity caused by drug interactions between MEK inhibitors and other drugs in the management of patients with metastatic melanoma.

Mechanisms of Acquired BRAF Inhibitor Resistance in Melanoma: A Systematic Review

This systematic review investigated the literature on acquired v-raf murine sarcoma viral oncogene homolog B1 (BRAF) inhibitor resistance in patients with melanoma. We searched MEDLINE for articles on BRAF inhibitor resistance in patients with melanoma published since January 2010 in the following areas: (1) genetic basis of resistance; (2) epigenetic and transcriptomic mechanisms; (3) influence of the immune system on resistance development; and (4) combination therapy to overcome resistance. Common resistance mutations in melanoma are BRAF splice variants, BRAF amplification, neuroblastoma RAS viral oncogene homolog (NRAS) mutations and mitogen-activated protein kinase kinase 1/2 (MEK1/2) mutations. Genetic and epigenetic changes reactivate previously blocked mitogen-activated protein kinase (MAPK) pathways, activate alternative signaling pathways, and cause epithelial-to-mesenchymal transition. Once BRAF inhibitor resistance develops, the tumor microenvironment reverts to a low immunogenic state secondary to the induction of programmed cell death ligand-1. Combining a BRAF inhibitor with a MEK inhibitor delays resistance development and increases duration of response. Multiple other combinations based on known mechanisms of resistance are being investigated. BRAF inhibitor-resistant cells develop a range of 'escape routes', so multiple different treatment targets will probably be required to overcome resistance. In the future, it may be possible to personalize combination therapy towards the specific resistance pathway in individual patients.

Cardiovascular Toxicity of Targeted Therapies for Cancer: An Overview of Systematic Reviews

Background

Several targeted therapies for cancer have been associated with cardiovascular toxicity. The evidence for this association has not been synthesized systematically nor has the quality of evidence been considered. We synthesized systematic review evidence of cardiovascular toxicity of individual targeted agents.

Methods

We searched MEDLINE, Embase, and the Cochrane Database of Systematic Reviews for systematic reviews with meta-analyses of cardiovascular outcomes for individual agents published to May 2020. We selected reviews according to prespecified eligibility criteria (International Prospective Register of Systematic Reviews CRD42017080014). We classified evidence of cardiovascular toxicity as sufficient, probable, possible, or indeterminate for specific cardiovascular outcomes based on statistical significance, study quality, and size.

Results

From 113 systematic reviews, we found at least probable systematic review evidence of cardiovascular toxicity for 18 agents, including high- and all-grade hypertension for bevacizumab, ramucirumab, axitinib, cediranib, pazopanib, sorafenib, sunitinib, vandetanib, aflibercept, abiraterone, and enzalutamide, and all-grade hypertension for nintedanib; high- and all-grade arterial thromboembolism (includes cardiac and/or cerebral events) for bevacizumab and abiraterone, high-grade arterial thromboembolism for trastuzumab, and all-grade arterial thromboembolism for sorafenib and tamoxifen; high- and all-grade venous thromboembolism (VTE) for lenalidomide and thalidomide, high-grade VTE for cetuximab and panitumumab, and all-grade VTE for bevacizumab; high- and all-grade left ventricular ejection fraction decline or congestive heart failure for bevacizumab and trastuzumab, and all-grade left ventricular ejection fraction decline/congestive heart failure for pazopanib and sunitinib; and all-grade corrected QT interval prolongation for vandetanib.

Conclusions

Our review provides an accessible summary of the cardiovascular toxicity of targeted therapy to assist clinicians and patients when managing cardiovascular health.

Efficacy and Adverse Events in Metastatic Melanoma Patients Treated with Combination BRAF Plus MEK Inhibitors Versus BRAF Inhibitors: A Systematic Review

We reviewed the literature to assess the efficacy and risk of constitutional, cardiac, gastrointestinal, and dermatological toxicities of combined BRAF plus MEK inhibitors versus BRAF inhibitors alone in patients with metastatic melanoma with BRAF mutations. Searches were conducted in PubMed, Cochrane Database of Systematic Reviews, Google scholar, ASCO, Scopus, and EMBASE for reports published from January 2010 through March 2019. Efficacy, including progression-free survival (PFS) and overall survival (OS) rates, were assessed by hazard ratio (HR); objective response rates (ORR) were assessed by odds ratio (OR). The randomized clinical trials (RCTs) with comparison to vemurafenib monotherapy were included to determine constitutional, gastrointestinal, cardiac, and dermatological toxicities using PRISMA statistical analysis with relative risk (RR) for equal comparison to avoid inclusion bias. Five RTCs comprising 2307 patients were included to assess efficacy, while three of the five RCTs comprising 1776 patients were included to assess adverse events. BRAF plus MEK inhibitor combination therapy demonstrated overall better efficacy compared to BRAF inhibitor monotherapy. Combination therapies appear to have favorable dermatologic side effect profiles, similar constitutional and cardiac profiles, and slightly worse gastrointestinal profiles compares to monotherapy regimens.

Clinical outcomes of BRAF plus MEK inhibition in melanoma: A meta-analysis and systematic review

Background

Melanoma is a potentially fatal malignancy with poor prognosis. Several recent studies have demonstrated that combination therapy of BRAF and MEK inhibition achieved better curative effect and appeared less toxic effects. We conducted a meta‐analysis to evaluate the efficacy and safety between BRAF inhibition plus MEK inhibition combination therapy and BRAF inhibition monotherapy in melanoma patients.

Methods

We performed the search in PubMed, EMBASE, and the Cochrane Library from January 2010 to January 2019. Inclusion and exclusion of studies, assessment of quality, outcome measures, data extraction, and synthesis were independently accomplished by two reviewers. Revman 5.3 software was used for the meta‐analysis.

Results

Totally, seven randomized controlled trials involving 3146 patients met our inclusion criteria. Comparing the results of combination therapy and monotherapy, combination therapy significantly improved OS (RR = 1.13; 95% CI, 1.08, 1.19; P < 0.00001), ORR (RR = 1.36; 95% CI, 1.28, 1.45; P < 0.00001), PFS (RR = 0.57; 95% CI, 0.52, 0.63; P < 0.00001) and reduced deaths (RR = 0.78; 95% CI, 0.69, 0.88; P < 0.0001). Skin‐related adverse events such as hyperkeratosis, cutaneous squamous‐cell carcinoma were less compared with monotherapy. However, gastrointestinal events like nausea, diarrhea, and vomiting were at a higher frequency.

Conclusion

Doublet BRAF and MEK inhibition achieved better survival outcomes over single‐agent BRAF inhibition and occurred less skin‐related events, but gastrointestinal events were more in combination therapy.

Cardiovascular Adverse Events Associated With BRAF and MEK Inhibitors: A Systematic Review and Meta-analysis

IMPORTANCE

Cardiovascular adverse events (CVAEs) after treatment with BRAF and MEK inhibitors in patients with melanoma remain incompletely characterized.

OBJECTIVE

To determine the association of BRAF and MEK inhibitor treatment with CVAEs in patients with melanoma compared with BRAF inhibitor monotherapy.

DATA SOURCES

PubMed, Cochrane, and Web of Science were systematically searched for keywords vemurafenib, dabrafenib, encorafenib, trametinib, binimetinib, and cobinimetinib from database inception through November 30, 2018.

STUDY SELECTION

Randomized clinical trials reporting on CVAEs in patients with melanoma being treated with BRAF and MEK inhibitors compared with patients with melanoma being treated with BRAF inhibitor monotherapy were selected.

DATA EXTRACTION AND SYNTHESIS

Data assessment followed the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines. Pooled relative risks (RRs) and 95% CIs were determined using random-effects and fixed-effects analyses. Subgroup analyses were conducted to assess study-level characteristics associated with CVAEs.

MAIN OUTCOMES AND MEASURES

The selected end points were pulmonary embolism, a decrease in left ventricular ejection fraction, arterial hypertension, myocardial infarction, atrial fibrillation, and QTc interval prolongation. All-grade and high-grade (≥3) CVAEs were recorded.

RESULTS

Overall, 5 randomized clinical trials including 2317 patients with melanoma were selected. Treatment with BRAF and MEK inhibitors was associated with an increased risk of pulmonary embolism (RR, 4.36; 95% CI, 1.23-15.44; P = .02), a decrease in left ventricular ejection fraction (RR, 3.72; 95% CI, 1.74-7.94; P < .001), and arterial hypertension (RR, 1.49; 95% CI, 1.12-1.97; P = .005) compared with BRAF inhibitor monotherapy. The RRs for myocardial infarction, atrial fibrillation, and QTc prolongation were similar between the groups. These results were consistent when assessing high-grade CVAEs (left ventricular ejection fraction: RR, 2.79; 95% CI, 1.36-5.73; P = .005; I2 = 29%; high-grade arterial hypertension: RR, 1.54; 95% CI, 1.14-2.08; P = .005; I2 = 0%), but RRs for high-grade pulmonary embolism were similar between groups. A higher risk of a decrease in left ventricular ejection fraction was associated with patients with a mean age younger than 55 years (RR, 26.50; 95% CI, 3.58-196.10; P = .001), and the associated risk of pulmonary embolism was higher for patients with a mean follow-up time longer than 15 months (RR, 7.70; 95% CI, 1.40-42.12; P = .02).

CONCLUSIONS AND RELEVANCE

Therapy with BRAF and MEK inhibitors was associated with a higher risk of CVAEs compared with BRAF inhibitor monotherapy. The findings may help to balance between beneficial melanoma treatment and cardiovascular morbidity and mortality.

Tolerability of BRAF/MEK inhibitor combinations: adverse event evaluation and management

The inhibition of the mitogen-activated protein kinases signalling pathway through combined use of BRAF and MEK inhibitors (BRAFi+MEKi) represents an established therapeutic option in patients with BRAF-mutated, advanced melanoma. These efficient therapies are well tolerated with mostly moderate and reversible side effects and a discontinuation rate due to adverse events of 11.5%-15.7%. Median duration of therapy ranges between 8.8 and 11.7 months. Based on data from confirmatory trials, safety profiles of three BRAFi+MEKi combinations were reviewed, that is, dabrafenib plus trametinib, vemurafenib plus cobimetinib and encorafenib plus binimetinib. Many adverse events are class effects, such as cutaneous, gastrointestinal, ocular, cardiac and musculoskeletal events; some adverse events are substance associated. Fever (dabrafenib) and photosensitivity (vemurafenib) are the most common and clinically prominent examples. Other adverse events are less frequent and the association to one substance is less strong such as anaemia, facial paresis (encorafenib), neutropenia (dabrafenib), skin rash, QTc prolongation and increased liver function tests (vemurafenib). This narrative review provides recommendations for monitoring, adverse event evaluation and management focusing on the clinically relevant side effects of the three regimens.

Automatic extraction of quantitative data from ClinicalTrials.gov to conduct meta-analyses

OBJECTIVES

Systematic reviews and meta-analyses are labor-intensive and time-consuming. Automated extraction of quantitative data from primary studies can accelerate this process. ClinicalTrials.gov, launched in 2000, is the world's largest trial repository of results data from clinical trials; it has been used as a source instead of journal articles. We have developed a Web application called EXACT (EXtracting Accurate efficacy and safety information from ClinicalTrials.gov) that allows users without advanced programming skills to automatically extract data from ClinicalTrials.gov in analysis-ready format. We have also used the automatically extracted data to examine the reproducibility of meta-analyses in three published systematic reviews.

STUDY DESIGN AND SETTING

We developed a Python-based software application (EXACT) that automatically extracts data required for meta-analysis from the ClinicalTrials.gov database in a spreadsheet format. We confirmed the accuracy of the extracted data and then used those data to repeat meta-analyses in three published systematic reviews. To ensure that we used the same statistical methods and outcomes as the published systematic reviews, we repeated the meta-analyses using data manually extracted from the relevant journal articles. For the outcomes whose results we were able to reproduce using those journal article data, we examined the usability of ClinicalTrials.gov data.

RESULTS

EXACT extracted data at ClincalTrials.gov with 100% accuracy, and it required 60% less time than the usual practice of manually extracting data from journal articles. We found that 87% of the data elements extracted using EXACT matched those extracted manually from the journal articles. We were able to reproduce 24 of 28 outcomes using the journal article data. Of these 24 outcomes, we were able to reproduce 83.3% of the published estimates using data at ClinicalTrials.gov.

CONCLUSION

EXACT (http://bio-nlp.org/EXACT) automatically and accurately extracted data elements from ClinicalTrials.gov and thus reduced time in data extraction. The ClinicalTrials.gov data reproduced most meta-analysis results in our study, but this conclusion needs further validation.

Comprehensive review of cardiovascular toxicity of drugs and related agents

Cardiovascular diseases are a leading cause of morbidity and mortality in most developed countries of the world. Pharmaceuticals, illicit drugs, and toxins can significantly contribute to the overall cardiovascular burden and thus deserve attention. The present article is a systematic overview of drugs that may induce distinct cardiovascular toxicity. The compounds are classified into agents that have significant effects on the heart, blood vessels, or both. The mechanism(s) of toxic action are discussed and treatment modalities are briefly mentioned in relevant cases. Due to the large number of clinically relevant compounds discussed, this article could be of interest to a broad audience including pharmacologists and toxicologists, pharmacists, physicians, and medicinal chemists. Particular emphasis is given to clinically relevant topics including the cardiovascular toxicity of illicit sympathomimetic drugs (e.g., cocaine, amphetamines, cathinones), drugs that prolong the QT interval, antidysrhythmic drugs, digoxin and other cardioactive steroids, beta-blockers, calcium channel blockers, female hormones, nonsteroidal anti-inflammatory, and anticancer compounds encompassing anthracyclines and novel targeted therapy interfering with the HER2 or the vascular endothelial growth factor pathway.

Cutaneous toxicities of new treatments for melanoma

New drugs against advanced melanoma have emerged during last decade. Target therapy and immunotherapy have changed the management of patients with metastatic disease. Along with its generalized use, drug toxicities have appeared and the skin is the target organ of a significant part of them. This revision summarizes the most common side effects and consensus management to improve the compliance of therapies and patients' quality of life. Among the BRAF inhibitors, main cutaneous side effects are photosensitivity, plantar hyperkeratosis, and the appearance of verrucal keratosis or squamous cell carcinoma. Special attention must be paid to the development of new primary melanomas or changes on nevi during BRAF inhibitor therapy. The most common cutaneous side effects of immunotherapy are rash, pruritus, and vitiligo. It remains controversial the possible role of these toxicities as markers of response to therapy.

Efficacy and safety of BRAF inhibition alone versus combined BRAF and MEK inhibition in melanoma: a meta-analysis of randomized controlled trials

Recent clinical studies have shown that combination therapy of BRAF and MEK inhibition provides more survival benefit than BRAF inhibition monotherapy. However, the adverse events due to BRAF and MEK inhibitors impact the physical comfort and social life of patients. Thus, in this study we have undertaken a meta-analysis of randomized controlled trials to compare the efficacy and adverse events risk between monotherapy and combination therapy. We identified the relevant studies by searching PubMed, EMBASE and Google scholar databases, between the year January 2000 and May 2016. Based on the heterogeneity, the fixed- or random-effects models were employed to analyze the efficacy and the incidence rate of adverse events. In addition, the subgroup analyses were conducted to overcome the effects of heterogeneity. Finally, our study included five RCTs, involving 1730 patients for this meta-analysis. The fixed-effects model demonstrated that combination therapy of BRAF and MEK inhibition provided more survival benefit in terms of ORR, PFS and OS (P < 0.00001). But, the combination therapy also significantly increased the incidences of pyrexia, chills, vomiting, chorioretinopathy, retinal detachment, hypertension, night sweats, increased aspartate aminotransferase and creatine kinase levels (P < 0.05) as compared to monotherapy. But, based on the significantly better survival outcomes, the combined BRAF and MEK inhibition will obviously be the mainstay therapy for the BRAF V600-mutant melanoma. However, a set of adverse events should be paid attention when physicians consider combination therapy.

Updates in Therapy for Advanced Melanoma

Cutaneous melanoma is one of the most aggressive forms of skin cancer, and is correlated with a large proportion of skin cancer-related deaths. Therapy for cutaneous melanoma has advanced greatly through careful identification of therapeutic targets and the development of novel immunotherapeutic approaches. The identification of BRAF as well as other driver mutations, have allowed for a specialized approach to treatment. In addition, immune checkpoint inhibition has dramatically changed the treatment landscape over the past 5-10 years. The successful targeting of CTLA-4, as well as PD-1/PD-L1, has been translated into meaningful clinical benefit for patients, with multiple other potential agents in development. Systemic therapy for cutaneous melanoma is becoming more nuanced and often takes a multifaceted strategy. This review aims to discuss the benefits and limitations of current therapies in systemic melanoma treatment as well as areas of future development.