An overview of binimetinib for the treatment of melanoma

Real-World Evidence of the Prevalence of Driver Mutations in Anorectal Melanoma

INTRODUCTION

Anorectal melanoma is a rare neoplasm with an aggressive behavior and poor prognosis. Recently, recurrent gene mutations related to anorectal melanoma have been identified in a small series of cases, and this holds promise for targeted therapies, analogous to cutaneous melanoma. The purpose of this study was to analyze testing rates and prevalence of mutations in anorectal melanoma in the Dutch population.

METHODS

The Netherlands Cancer Registry and the Dutch Nationwide Pathology Databank were queried for all patients with a diagnosis of anorectal melanoma (2009-2019) and for whom a molecular analysis was performed. The genes that were tested and mutations that were reported were recorded. Mutation status was correlated with clinical characteristics.

RESULTS

In the period 2009-2019, 121 patients were diagnosed with anorectal melanoma. A molecular analysis was performed for 81 (67%) using single gene testing and various next-generation sequencing panels. Testing rates increased from 53% in 2009-2012 to 73% in 2016-2019. In 29/81 (36%) analyzed tumors, one or more mutations were reported: mutations in KIT (16/70, 23%), CTNNB1 (3/20, 15%), NRAS (6/60, 10%), BRAF non-V600E (4/74, 5%), GNAS (1/19, 5%), KRAS (1/28, 4%), BRAF V600E (1/74, 1%), and SF3B1 (1/1). In this cohort, a positive correlation was found between BRAF mutation status and age. Mutation status did not correlate with sex, date of diagnosis, tumor stage or surgical treatment. Survival was not influenced by any mutation status.

CONCLUSION

KIT was the most frequently mutated gene in the 81 analyzed anorectal melanomas in the period 2009-2019. With the increasing testing rates and use of next generation sequencing, the molecular landscape of anorectal melanomas is gradually being revealed. Adoption of broad mutation analysis will reveal potentially actionable targets for treatment of patients with anorectal melanoma.

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.

Targeting the epigenome in malignant melanoma: Facts, challenges and therapeutic promises

Malignant melanoma is the most lethal type of skin cancer with high rates of mortality. Although current treatment options provide a short-clinical benefit, acquired-drug resistance highlights the low 5-year survival rate among patients with advanced stage of the disease. In parallel, the involvement of an aberrant epigenetic landscape, (e.g., alterations in DNA methylation patterns, histone modifications marks and expression of non-coding RNAs), in addition to the genetic background, has been also associated with the onset and progression of melanoma. In this review article, we report on current therapeutic options in melanoma treatment with a focus on distinct epigenetic alterations and how their reversal, by specific drug compounds, can restore a normal phenotype. In particular, we concentrate on how single and/or combinatorial therapeutic approaches have utilized epigenetic drug compounds in being effective against malignant melanoma. Finally, the role of deregulated epigenetic mechanisms in promoting drug resistance to targeted therapies and immune checkpoint inhibitors is presented leading to the development of newly synthesized and/or improved drug compounds capable of targeting the epigenome of malignant melanoma.

Novel therapeutic strategy for melanoma based on albendazole and the CDK4/6 inhibitor palbociclib

Although an increasing number of patients benefit from immunotherapy and targeted therapies, melanoma remains incurable with increasing incidence. Drug repositioning and repurposing is an alternative strategy to discover and develop novel anticancer drugs or combined therapeutic regimens. In this study, we demonstrated that albendazole (ABZ), an Food and Drug Administration (FDA)-approved broad-spectrum antiparasitic agent, significantly inhibits the proliferation of melanoma cells in vitro and in vivo. RNA sequencing and flow cytometry analysis revealed that ABZ arrests melanoma cells at the G2/M phase of the cell cycle and induces cell apoptosis. More importantly, the CDK4/6 inhibitor palbociclib, as a member of the first and only class of highly specific CDK inhibitors approved for cancer treatment to date, showed significant synergistic effects with ABZ treatment in melanoma cells and mouse models. Taken together, we revealed a previously unappreciated function of ABZ in antimelanoma proliferation by inducing cell cycle arrest and apoptosis and provided a novel combined therapeutic regimen of ABZ plus CDK4/6 inhibitor treatment in melanoma.

Synthesis, structure and in vitro antiproliferative effects of alkyne-linked 1,2,4-thiadiazole hybrids including erlotinib- and ferrocene-containing derivatives

Chemotherapy is an indispensable tool to treat cancer, therefore, the development of new drugs that can treat cancer with minimal side effects and lead to more favorable prognoses is of crucial importance. A series of eleven novel 1,2,4-thiadiazoles bearing erlotinib (a known anticancer agent), phenylethynyl, ferrocenyl, and/or ferrocenethynyl moieties were synthesized in this work and characterized by NMR, IR and mass spectroscopies. The solid-phase structures were determined by single-crystal X-ray diffraction. Partial isomerisation of bis(erlotinib)-1,2,4-thiadiazole into its 1,3,4-thiadiazole isomer, leading to the isolation of a 3 : 2 isomer mixture, was observed and a plausible mechanism for isomerisation is suggested. The in vitro cytostatic effect and the long-term cytotoxicity of these thiadiazole-hybrids, as well as that of erlotinib, 3,5-dichloro-1,2,4-thiadiazole and 3,5-diiodo-1,2,4-thiadiazole were investigated against A2058 human melanoma, HepG2 human hepatocellular carcinoma, U87 human glioma, A431 human epidermoid carcinoma, and PC-3 human prostatic adenocarcinoma cell lines. Interestingly, erlotinib did not exhibit a significant cytostatic effect against these cancer cell lines. 1,2,4-Thiadiazole hybrids bearing one erlotinib moiety or both an iodine and a ferrocenethynyl group, as well as 3,5-diiodo-1,2,4-thiadiazole demonstrated good to moderate cytostatic effects. Among the synthesized 1,2,4-thiadiazole hybrids, the isomer mixture of bis-erlotinib substituted 1,2,4- and 1,3,4-thiadiazoles showed the most potent activity. This isomer mixture was proven to be the most effective in long-term cytotoxicity, too. 3,5-Diiodo-1,2,4-thiadiazole and its hybrid with one erlotinib fragment were also highly active against A431 and PC-3 proliferation. These novel compounds may serve as new leads for further study of their antiproliferative properties.

New perspectives on targeting RAF, MEK and ERK in melanoma

PURPOSE OF REVIEW

Although immune checkpoint inhibitors and small molecule inhibitors targeting the MAPK pathway have revolutionized the management of metastatic melanoma, long-term disease control occurs only for a minority of patients because of multiple resistance mechanisms. One way to tackle resistance is to develop the next-generation of RAF, MEK and ERK inhibitors using our understanding of the molecular mechanisms that fine-tune the MAPK pathway.

RECENT FINDINGS

Studies on the regulation of the MAPK pathway have revealed a dominant role for homo-dimerization and hetero-dimerization of RAF, MEK and ERK. Allosteric inhibitors that break these dimers are, therefore, undergoing various stages of preclinical and clinical evaluation. Novel MEK inhibitors are less susceptible to differences in MEK's activation state and do not drive the compensatory activation of MEK that could limit efficacy. Innovations in targeting ERK originate from dual inhibitors that block MEK-catalyzed ERK phosphorylation, thereby limiting the extent of ERK reactivation following feedback relief.

SUMMARY

The primary goal in RAF, MEK and ERK inhibitors' development is to produce molecules with less inhibitor paradox and off-target effects, giving robust and sustained MAPK pathway inhibition.

Comprehensive NGS Panel Validation for the Identification of Actionable Alterations in Adult Solid Tumors

The increasing identification of driver oncogenic alterations and progress of targeted therapies addresses the need of comprehensive alternatives to standard molecular methods. The translation into clinical practice of next-generation sequencing (NGS) panels is actually challenged by the compliance of high quality standards for clinical accreditation. Herein, we present the analytical and clinical feasibility study of a hybridization capture-based NGS panel (Action OncoKitDx) for the analysis of somatic mutations, copy number variants (CNVs), fusions, pharmacogenetic SNPs and Microsatellite Instability (MSI) determination in formalin-fixed paraffin-embedded (FFPE) tumor samples. A total of 64 samples were submitted to extensive analytical validation for the identification of previously known variants. An additional set of 166 tumor and patient-matched normal samples were sequenced to assess the clinical utility of the assay across different tumor types. The panel demonstrated good specificity, sensitivity, reproducibility, and repeatability for the identification of all biomarkers analyzed and the 5% limit of detection set was validated. Among the clinical cohorts, the assay revealed pathogenic genomic alterations in 97% of patient cases, and in 82.7%, at least one clinically relevant variant was detected. The validation of accuracy and robustness of this assay supports the Action OncoKitDx's utility in adult solid tumors.

Binimetinib Is a Potent Reversible and Time-Dependent Inhibitor of Cytochrome P450 1A2

Binimetinib is a selective MEK1/2 inhibitor, which is indicative of melanoma. We aimed to investigate the inhibitory effect of binimetinib on cytochrome P450 using human liver microsomes. Binimetinib was demonstrated to display reversible and time-dependent inhibitory effects on human CYP1A2. Binimetinib can inhibit the activity of phenacetin deethylation with IC₅₀ of 5.6 μM. A 30 min preincubation of binimetinib with NADPH-supplemented human liver microsomes raised a significant left IC₅₀ shift (6.5-fold), from 5.69-0.88 μM. The inactivation parameters K_inact and K_I were 0.063 min^-1 and 15.47 μM, and the half-life of inactivation was 11 min. Glutathione (GSH) and catalase/superoxide exhibited minor or no protective effect on binimetinib-induced enzyme inactivation. Trapping experiment by GSH induced a detection of GSH adduct, of which the formation was believed to be through the oxidation of electron-rich 1,4-benzenediamine to reactive 1,4-diiminoquinone species. Cytochrome P450 3A4, 2C9, and 2D6 were involved in the bioactivation of binimetinib. In conclusion, binimetinib was proven to display reversible and time-dependent inhibitory effect on CYP1A2, which may have implications for the toxicity of binimetinib.