Cutaneous manifestations of dabrafenib (GSK2118436): a selective inhibitor of mutant BRAF in patients with metastatic melanoma

New pyrazolylindolin-2-one based coumarin derivatives as anti-melanoma agents: design, synthesis, dual BRAFV600E/VEGFR-2 inhibition, and computational studies

Malignant melanoma is the most invasive skin cancer with the highest risk of death. The inhibition of BRAFV600E appears relevant for overcoming secondary resistance developed during melanoma treatment. BRAFV600E triggers angiogenesis via modification of the expression of angiogenic inducers, which play a crucial role in the metastasis of melanoma. Accordingly, the dual inhibition of the BRAFV600E/VEGFR-2 signaling pathway is considered a rational approach in the design of anti-melanoma candidates. In this study, a new class of pyrazolylindolin-2-one linked coumarin derivatives as dual BRAFV600E/VEGFR-2 inhibitors targeting A375 melanoma cells was designed. Target compounds were tailored to occupy the pockets of BRAFV600E and VEGFR-2. Most of the synthesized compounds demonstrated potent mean growth inhibitory activity against A375 cells. Compound 4j was the most active cytotoxic derivative, displaying an IC50 value at a low micromolar concentration of 0.96 μM with a significant safety profile. Moreover, 4j showed dual potent inhibitory activity against BRAFV600E and VEGFR-2 (IC50 = 1.033 and 0.64 μM, respectively) and was more active than the reference drug sorafenib. Furthermore, derivative 4j caused significant G0/G1 cell cycle arrest, induced apoptosis, and inhibited the migration of melanoma cells. Molecular docking showed that compound 4j achieved the highest ΔG value of -9.5 kcal mol-1 against BRAFV600E and significant ΔG of -8.47 kcal mol-1 against VEGFR-2. Furthermore, the structure-activity relationship study revealed that TPSA directly contributed to the anticancer activity of the tested compounds.

Non-syndromic and Syndromic Severe Acne in Adolescent Patients

Acne is a common skin disorder in adolescents. However, severe acne that is persistent and refractory to conventional treatment or has other associated symptoms should raise suspicion for non-syndromic or syndromic acne.

Cutaneous Side Effects of Modern Targeted Therapy and Immunotherapy in Patients with Dermatological Malignancies

The advent of immunotherapy and targeted therapies in treating dermatological malignancies has dramatically changed the landscape of dermato-oncology in recent years. Their superior efficacy compared to previous therapeutic options, such as chemotherapy, has resulted in their use in treating devastating malignancies, such as melanoma or unresectable/metastatic basal cell and squamous cell carcinoma. Skin toxicity is a critical safety consideration, among other adverse reactions, that can occur under treatment with these agents. This article aims to summarize the cutaneous side effects of immune checkpoint inhibitors and targeted dermato-oncological therapies. Although the skin side effects of these agents are primarily mild, they can occasionally affect the decision for treatment continuation and the quality of life of the affected patients. Therefore, physicians must be acquainted with the specific cutaneous toxicity profile of such treatments to mitigate their impact on the patients and optimize the overall outcome of dermato-oncological therapy.

Advances in cutaneous squamous cell carcinoma

Human malignancies arise predominantly in tissues of epithelial origin, where the stepwise transformation from healthy epithelium to premalignant dysplasia to invasive neoplasia involves sequential dysregulation of biological networks that govern essential functions of epithelial homeostasis. Cutaneous squamous cell carcinoma (cSCC) is a prototype epithelial malignancy, often with a high tumour mutational burden. A plethora of risk genes, dominated by UV-induced sun damage, drive disease progression in conjunction with stromal interactions and local immunomodulation, enabling continuous tumour growth. Recent studies have identified subpopulations of SCC cells that specifically interact with the tumour microenvironment. These advances, along with increased knowledge of the impact of germline genetics and somatic mutations on cSCC development, have led to a greater appreciation of the complexity of skin cancer pathogenesis and have enabled progress in neoadjuvant immunotherapy, which has improved pathological complete response rates. Although measures for the prevention and therapeutic management of cSCC are associated with clinical benefit, the prognosis remains poor for advanced disease. Elucidating how the genetic mechanisms that drive cSCC interact with the tumour microenvironment is a current focus in efforts to understand, prevent and treat cSCC.

A Retrospective, Single-Institution Experience of Bullous Pemphigoid as an Adverse Effect of Immune Checkpoint Inhibitors

Simple Summary

This article investigates the cutaneous adverse immune effects induced by immune checkpoint inhibitors. These drugs target proteins expressed on cancer cells that aid in the avoidance of immune system detection and destruction. Immune checkpoint inhibitors inadvertently cause other immune-mediated adverse effects. Cutaneous toxicities are the commonest adverse effect from immunotherapy; furthermore, they are usually developed early in the course of treatment. A rare and severe cutaneous adverse event is Bullous Pemphigoid. This article investigates the average and median onset of these drug toxicities, as well as treatments. We found these side effects to be negatively skewed, indicating most cases occur several months into treatment.

Abstract

Immune checkpoint inhibitors are a class of cancer treatment drugs that stimulate the immune system’s ability to fight tumor cells. These drugs are monoclonal antibodies targeting im-mune-inhibiting proteins on cancer cells, such as CTLA-4 and PD-1/PD-L1. Immune checkpoint inhibitors cause many immune-related adverse events. Cutaneous toxicities are of the most common adverse effects and occur with a range of severity. Bullous Pemphigoid is a rare adverse event with a high impact on quality of life that may occur after immune checkpoint inhibitor treatment. In this article, we investigate current research on immune checkpoint inhibitors, cutaneous adverse events, and common presentations and treatments, with a specific focus on Bullous Pemphigoid, its characteristics, onset timing, and treatment. Significant findings include a negative skew in the onset of presentation. Furthermore, we describe exclusive cases.

Hemidesmosomal Reactivity and Treatment Recommendations in Immune Checkpoint Inhibitor-Induced Bullous Pemphigoid—A Retrospective, Monocentric Study

Immune checkpoint inhibitors (ICI) induce T-cell-mediated antitumour responses. While ICI were initially successfully applied in metastasized melanoma, they are now approved for several tumour entities. Numerous autoimmune disorders have been reported to occur as adverse events of the treatment, among them bullous pemphigoid (BP), with less than 1% of the patients experiencing ICI-induced BP. This number is higher than the estimated prevalence of autoimmune bullous diseases in the general population of Germany, which lies around 0.05%. We here describe our cohort of eight patients, who developed a bullous pemphigoid under or shortly after ICI treatment. Half of them had a severe subtype (as shown by BPDAI >57) and showed a median onset of ICI-BP after 10 months of ICI initiation. Six patients had a palmar and/or plantar involvement, while oral involvement occurred in one case. All patients had linear epidermal IgG depositions in split skin in the indirect immunofluorescence. In four out of five biopsies available for direct immunofluorescence, linear IgG and C3 depositions were detected at the basement membrane, while one patient showed linear IgM staining. Moderate to high levels of FLBP180 autoantibodies were found in seven of eight cases. The disease can still be active after ICI discontinuation, while rituximab might be required for remission. Finally, four tumour samples were stained histochemically for collagen XVII (BP180), but no enhanced expression was found.

New Potential Agents for Malignant Melanoma Treatment-Most Recent Studies 2020-2022

Malignant melanoma (MM) is the most lethal skin cancer. Despite a 4% reduction in mortality over the past few years, an increasing number of new diagnosed cases appear each year. Long-term therapy and the development of resistance to the drugs used drive the search for more and more new agents with anti-melanoma activity. This review focuses on the most recent synthesized anti-melanoma agents from 2020-2022. For selected agents, apart from the analysis of biological activity, the structure-activity relationship (SAR) is also discussed. To the best of our knowledge, the following literature review delivers the latest achievements in the field of new anti-melanoma agents.

On the development of B-Raf inhibitors acting through innovative mechanisms

B-Raf is a protein kinase participating to the regulation of many biological processes in cells. Several studies have demonstrated that this protein is frequently upregulated in human cancers, especially when it bears activating mutations. In the last years, few ATP-competitive inhibitors of B-Raf have been marketed for the treatment of melanoma and are currently under clinical evaluation on a variety of other types of cancer. Although the introduction of drugs targeting B-Raf has provided significant advances in cancer treatment, responses to ATP-competitive inhibitors remain limited, mainly due to selectivity issues, side effects, narrow therapeutic windows, and the insurgence of drug resistance.

Impressive research efforts have been made so far towards the identification of novel ATP-competitive modulators with improved efficacy against cancers driven by mutant Raf monomers and dimers, some of them showing good promises. However, several limitations could still be envisioned for these compounds, according to literature data. Besides, increased attentions have arisen around approaches based on the design of allosteric modulators, polypharmacology, proteolysis targeting chimeras (PROTACs) and drug repurposing for the targeting of B-Raf proteins. The design of compounds acting through such innovative mechanisms is rather challenging. However, valuable therapeutic opportunities can be envisioned on these drugs, as they act through innovative mechanisms in which limitations typically observed for approved ATP-competitive B-Raf inhibitors are less prone to emerge. In this article, current approaches adopted for the design of non-ATP competitive inhibitors targeting B-Raf are described, discussing also on the possibilities, ligands acting through such innovative mechanisms could provide for the obtainment of more effective therapies.

Structure-Based and Knowledge-Informed Design of B-Raf Inhibitors Devoid of Deleterious PXR Binding

Dabrafenib is an anticancer drug currently used in the clinics, alone or in combination. However, dabrafenib was recently shown to potently activate the human nuclear receptor pregnane X receptor (PXR). PXR activation increases the clearance of various chemicals and drugs, including dabrafenib itself. It may also enhance cell proliferation and tumor aggressiveness. Therefore, there is a need for rational design of a potent protein kinase B-Raf inhibitor devoid of binding to the secondary target PXR and resisting rapid metabolism. By determining the crystal structure of dabrafenib bound to PXR and analyzing its mode of binding to both PXR and its primary target, B-Raf-V600E, we were able to derive new compounds with nanomolar activity against B-Raf and no detectable affinity for PXR. The crystal structure of B-Raf in complex with our lead compound revealed a subdomain swapping of the activation loop with potentially important functional implications for a prolonged inhibition of B-Raf-V600E.

Dermatologic adverse events associated with targeted therapies for melanoma

INTRODUCTION

The development of new targeted therapies has considerably changed the therapeutic paradigm of melanoma, significantly increasing overall survival (OS) and progression-free survival (PFS). However, skin-related adverse sequelae might occur and impact on patients' quality of life.

AREAS COVERED

In this article we will cover the most important dermatological toxicities related to BRAF and MEK-inhibitors, along with updated management strategies.

EXPERT OPINION

BRAF inhibitors have represented a revolution in the treatment of melanoma. They have improved the outcome of the disease and therefore represent an important option in the management and care of patients with advanced melanoma. Skin toxicity (especially the onset of squamous skin carcinomas) has been considered a major cutaneous side effect and, although the addition of MEK inhibitors in combination has significantly reduced the incidence of skin sequelae, serious skin adverse events might develop anyway and impact significantly on patients'quality of life and on national health system budget. The introduction of BRAF and MEK inhibitors as a new effective adjuvant treatment option for stage III and ulcerated melanoma has proved a significant impact on the risk of recurrence, and may have interesting developments in the near future as a further therapeutic tool.

Diverse landscape of dermatologic toxicities from small-molecule inhibitor cancer therapy

BACKGROUND

Advances in molecular biology and genetics have contributed to breakthrough treatments directed at specific pathways associated with the development of cancer. Small-molecule inhibitors (Nibs) aimed at a variety of cellular pathways have been efficacious; however, they are associated with significant dermatologic toxicities.

METHODS

We conducted a comprehensive review of dermatologic toxicities associated with Nibs categorized into the following five groups: (a) mitogen-activated protein kinase; (b) growth factor/multi-tyrosine kinase; (c) cell division/DNA repair; (d) signaling associated with myeloproliferative neoplasms; and (e) other signaling pathways. Prospective phase I, II, or III clinical trials, retrospective literature reviews, systematic reviews/meta-analyses, and case reviews/reports were included for analysis.

RESULTS

Dermatologic toxicities reviewed were associated with every class of Nibs and ranged from mild to severe or life-threatening adverse skin reactions. Inflammatory reactions manifesting as maculopapular, papulopustular/acneiform, and eczematous lesions were frequent types of dermatologic toxicities seen with Nibs. Squamous cell carcinoma with keratoacanthoma-like features was associated with a subset of Nibs. Substantial overlap in dermatologic toxicities was found between Nibs.

CONCLUSIONS

Dermatologic toxicities from Nibs are diverse and may overlap between classes of Nibs. Recognition of the various types of toxicities from Nibs is critical for patient care in the era of "oncodermatology/dermatopathology."

Hyperkeratotic Skin Adverse Events Induced by Anticancer Treatments: A Comprehensive Review

Hyperkeratotic skin adverse events are a group of toxic effects, characterized by the disruption of epidermal homeostasis and interaction with keratinocyte proliferation/differentiation or keratinocyte survival, and frequently reported with systemic anticancer treatments. These types of reactions include hand-foot skin reaction or palmoplantar keratoderma, induced psoriasis, keratosis pilaris-like or pityriasis rubra pilaris-like rashes, Grover's disease, and contact hyperkeratosis. Cutaneous squamoproliferative lesions are also described because of the presence of abnormal keratinocyte proliferation. They are usually observed with tyrosine kinase inhibitors but have also been described in association with cytotoxic chemotherapeutic agents. Their pathogenesis is related mainly to the disruption of epidermal homeostasis and interaction with keratinocyte proliferation/differentiation or keratinocyte survival caused by anticancer treatment. Early recognition and adequate management are critical to prevent exacerbation of the lesions, to limit treatment interruption, and to minimize impairment of quality of life. This review summarizes the current knowledge concerning the presentation, pathogenesis, and management of secondary hyperkeratotic reactions to anticancer therapies. It also includes hyperkeratotic reactions that have been more recently described with newly approved targeted therapies or immune checkpoint inhibitors, such as keratosis pilaris-like exanthema with second-generation BCR-ABL inhibitors, lamellar ichthyosis-like lesions with ponatinib, pityriasis rubra pilaris with the newly approved selective phosphoinositide 3 kinase inhibitor idelalisib, or psoriasis with anti-programmed death-1 and programmed death ligand-1.

The Role of Senescent Cells in Acquired Drug Resistance and Secondary Cancer in BRAFi-Treated Melanoma

Simple Summary

Advances in melanoma treatment include v-Raf murine sarcoma viral oncogene homolog B (BRAF) inhibitors that target the predominant oncogenic mutation found in malignant melanoma. Despite initial success of the BRAF inhibitor (BRAFi) therapies, resistance and secondary cancer often occur. Mechanisms of resistance and secondary cancer rely on upregulation of pro-survival pathways that circumvent senescence. The repeated identification of a cellular senescent phenotype throughout melanoma progression demonstrates the contribution of senescent cells in resistance and secondary cancer development. Incorporating senotherapeutics in melanoma treatment may offer a novel approach for potentially improving clinical outcome.

Abstract

BRAF is the most common gene mutated in malignant melanoma, and predominately it is a missense mutation of codon 600 in the kinase domain. This oncogenic BRAF missense mutation results in constitutive activation of the mitogen-activate protein kinase (MAPK) pro-survival pathway. Several BRAF inhibitors (BRAFi) have been developed to specifically inhibit BRAF^V600 mutations that improve melanoma survival, but resistance and secondary cancer often occur. Causal mechanisms of BRAFi-induced secondary cancer and resistance have been identified through upregulation of MAPK and alternate pro-survival pathways. In addition, overriding of cellular senescence is observed throughout the progression of disease from benign nevi to malignant melanoma. In this review, we discuss melanoma BRAF mutations, the genetic mechanism of BRAFi resistance, and the evidence supporting the role of senescent cells in melanoma disease progression, drug resistance and secondary cancer. We further highlight the potential benefit of targeting senescent cells with senotherapeutics as adjuvant therapy in combating melanoma.

Keratoacanthoma: Update on the Debate

ABSTRACT

Keratoacanthoma (KA) is a cutaneous tumor with a biphasic pattern of growth. A rapidly growing phase is usually followed by involution. KA occurs on sun-damaged skin. There are many listed causative associations, which include some therapeutic agents. Debate continues as to whether KA is a variant of squamous carcinoma (SCC) or a separate entity. Reporting of KA versus SCC is markedly inconsistent. Reasons for inconsistency include overlapping microscopic criteria, variants of KA with more aggressive features, and possibly medicolegal concerns. Genetic studies have shown some differences between the 2 entities. Activation of apoptotic pathways has been demonstrated in KA. Genetic studies have shown a possible role of human polyomavirus 6 in the pathogenesis of at least some KAs. Given that some cases of KA have components that behave as conventional SCCs, KA can be considered as a low-grade variant of SCC with some genetic differences.

Design, synthesis, and biological evaluation of novel imidazole derivatives possessing terminal sulphonamides as potential BRAFV600Einhibitors

BRAF^V600E mutation has been detected in various malignant tumours. Developing of potent BRAF^V600E inhibitors is considered a leading step in the way to cure different cancer types. In the current work, a series of 38 4-(1H-imidazol-5-yl)pyridin-2-amine derivatives was designed and synthesized using Dabrafenib as a lead compound for structural-guided optimization. The target compounds were evaluated as potential anticancer agents against NCI 60 human cancer cell lines. In 5-dose testing mode, two compounds 14h and 16e were tested to determine their IC₅₀ values over each of the 60 cell lines. The selected candidates exhibited promising activity with mean IC₅₀ values of 2.4 µM and 3.6 µM, respectively. Melanoma cancer cell lines exhibited the highest sensitivity after the treatment with the tested compounds 14h and 16e. The mean IC₅₀ values of compounds 14h and 16e against Melanoma cancer cell lines are 1.8 µM and 1.88 µM, respectively. In addition, BRAF^V600E kinase inhibitory activity was determined for each derivative. Compounds 15i, 15j, 16a, and 16d were the most potent inhibitors against BRAF^V600E with IC₅₀ 76 nM, 32 nM, 35 nM, and 68 nM. The newly developed compounds represent a therapeutically promising approach for the treating various cancer types.

Keratoacanthoma, committed stem cells and neoplastic aberrant infundibulogenesis integral to formulating a conceptual model for an infundibulocystic pathway to squamous cell carcinoma

Keratoacanthomas (KAs) are distinctive tumors that are defined by their clinical and histopathological features. Their relationship and distinction from squamous cell carcinoma (SCC), however, remain controversial. All cytogenic and immunohistochemical markers that have been applied in this quest have failed. A close relationship of KAs to hair follicles has been recognized. The descriptive term infundibulocystic or infundibular SCC was introduced to define a more broad-based pathway encompassing KAs. The follicular infundibulum roles in respect to neoplasia and wound healing are important elements in understanding the pathogenesis of KAs. Mouse models for KA have provided insights into the relationship of KA to follicles and SCCs. These advances and together with the diverse clinical and histopathological aspects of KA have contributed to the formulation of a conceptual pathway. The central element is that ultraviolet (UV)-mutated or activated committed infundibular stem cells are driven by the combination of a mutated oncogenic RAS pathway linked with the Wnt/beta-catenin pathway responsible for stem cell maintenance, hair follicle development, wound healing and driving KA proliferation and terminal keratinization. The existence and activation of this mutated pathway may form the basis of the paradoxical emergence of KAs and SCCs in patients receiving BRAF and PD-1 inhibitor therapy.

The incidence and risk of cutaneous toxicities associated with dabrafenib in melanoma patients: a systematic review and meta-analysis

OBJECTIVE

Dabrafenib, an inhibitor of mutated BRAF, has significant clinical activity in melanoma patients but is linked to a spectrum of cutaneous toxicities. Thus, our meta-analysis was conducted to evaluate the type, incidence and risks of dermatological toxicities from dabrafenib.

METHODS

Systematic searches were performed using electronic databases such as Embase and PubMed and conference abstracts published by the American Society of Clinical Oncology. Eligible studies were limited to prospective phase I, II and III clinical trials and expanded-access (ie, outside clinical trials) programmes of melanoma patients receiving dabrafenib monotherapy (150 mg, twice daily) or combination therapy of dabrafenib (150 mg, twice daily) plus trametinib (2 mg, once daily). The outcomes were mainly the incidence rate and risk of all-grade cutaneous toxicities associated with dabrafenib in melanoma patients.

RESULTS

Twenty trials comprising a total of 3359 patients were included in the meta-analysis. The meta-analysis showed that the overall incidence of all-grade rash for melanoma patients assigned dabrafenib was 30.00% (95% CI 0.07 to 0.71), cutaneous squamous-cell carcinoma (cSCC) 16.00% (95% CI 0.11 to 0.24), alopecia 21% (95% CI 0.11 to 0.37), keratoacanthoma (KA) 20.00% (95% CI 0.12 to 0.31), hyperkeratosis (HK) 14.00% (95% CI 0.09 to 0.22) and pruritus 8.00% (95% CI 0.05 to 0.12). All-grade rash occurred in 19.00% (95% CI 0.15 to 0.25), cSCC in 10.00% (95% CI 0.04 to 0.22), alopecia in 6.00% (95% CI 0.03 to 0.12), KA in 6.00% (95% CI 0.04 to 0.09) and pruritus in 2/1265 patients assigned dabrafenib plus trametinib. The summary risk ratio (RR) showed that the combination of dabrafenib with trametinib versus dabrafenib was associated with a significantly increased risk of all-grade rash (RR 1.35, 95% CI 1.01 to 1.80) and a decreased risk of cSCC (RR 0.40, 95% CI 0.18 to 0.89), alopecia (RR 0.19, 95% CI 0.12 to 0.30) and HK (RR 0.25, 95% CI 0.10 to 0.62).

CONCLUSION

In summary, the most frequent cutaneous adverse reactions from dabrafenib were rash, cSCC, alopecia, KA, HK and pruritus. There was a significantly decreased risk of cSCC, alopecia and HK with the combination of dabrafenib with trametinib versus dabrafenib alone. Clinicians should be aware of these risks and perform regular clinical monitoring.

Cutaneous reactions in children treated with MEK inhibitors, BRAF inhibitors, or combination therapy: A multicenter study

BACKGROUND

Treatment with BRAF inhibitors (BRAFI) and MEK inhibitors (MEKI) causes cutaneous reactions in children, limiting dosing or resulting in treatment cessation. The spectrum and severity of these reactions is not defined.

OBJECTIVE

To determine the frequency and spectrum of cutaneous reactions in children receiving BRAFI and MEKI and their effects on continued therapy.

METHODS

A multicenter, retrospective study was conducted at 11 clinical sites in the United States and Canada enrolling 99 children treated with BRAFI and/or MEKI for any indication from January 1, 2012, to January 1, 2018.

RESULTS

All children in this study had a cutaneous reaction; most had multiple, with a mean per patient of 3.5 reactions on BRAFI, 3.7 on MEKI, and 3.4 on combination BRAFI/MEKI. Three patients discontinued treatment because of a cutaneous reaction. Treatment was altered in 27% of patients on BRAFI, 39.5% on MEKI, and 33% on combination therapy. The cutaneous reactions most likely to alter treatment were dermatitis, panniculitis, and keratosis pilaris-like reactions for BRAFI and dermatitis, acneiform eruptions, and paronychia for MEKI.

CONCLUSIONS

Cutaneous reactions are common in children receiving BRAFI and MEKI, and many result in alterations or interruptions in oncologic therapy. Implementing preventative strategies at the start of therapy may minimize cutaneous reactions.

Adverse cutaneous reactions to chemotherapeutic drugs

Drug reactions resulting from chemotherapy agents are common and frequently affect the skin. Although often benign, a select few of these cutaneous reactions may necessitate immediate changes to the antineoplastic regimens. Given the diversity of chemotherapeutic skin reactions and their complex implications on patient management, an organized conceptual schema is imperative for proper patient care. We evaluate a number of commonly seen chemotherapy-induced skin toxicities organized by pathogenic mechanism and drug class, providing a framework for the identification and categorization of adverse events to prevent unrecognition. Groupings of these reactions include direct cytotoxicity and/or drug accumulation, immunologic hypersensitivity, and aberrant molecular signaling.

Cutaneous Adverse Events of Anti-PD-1 Therapy and BRAF Inhibitors

OPINION STATEMENT

The treatment of advanced melanoma has undergone a dramatic transformation over the last decade with the advent of targeted and immunomodulatory therapies. This transition from cytotoxic chemotherapy has yielded improvements in both survival and quality of life; yet despite their therapeutic advantages, these treatments have been associated with a diverse range of cutaneous adverse events (AEs). These range from relatively benign eczematous conditions to more severe inflammatory and bullous disorders, and can include induction of second malignancies. AEs can result in serious morbidity and risk of mortality if not recognised and managed early. As a consequence of their novelty, and rapid uptake, these agents have been subject to intense scrutiny and there is a general understanding that cutaneous AEs should be anticipated in treatment plans. Dermatologists should be integrated into management teams to assist in the development of treatment protocols for anticipated common AEs and to provide expert management of more severe, rare or unusual AEs. Our experience has shown a reduction in treatment interruptions, more rapid recognition of unusual AEs and improved management pathways for patients suffering cutaneous AEs.

Risk factors for severe rash with use of vemurafenib alone or in combination with cobimetinib for advanced melanoma: pooled analysis of clinical trials

Background

Rash is one of the most common severe adverse events associated with use of vemurafenib for the treatment of melanoma, either as monotherapy or in combination with cobimetinib. The study aimed to identify pre-treatment patient characteristics predictive of developing severe rash with vemurafenib therapy.

Methods

This was a secondary pooled analysis of individual patient data from the BRIM-2, BRIM-3 and coBRIM clinical trials, including all patients treated with vemurafenib alone and vemurafenib plus cobimetinib. Patient age, sex, performance status, body weight, body mass index, liver function markers and estimated glomerular filtration rate were assessed for association with development of severe (grade 3 or 4) rash using logistic regression.

Results

Of 962 patients treated with vemurafenib, 150 (16%) patients experienced severe rash. Female sex was identified as a significant risk factor for severe rash development (P < 0.001), having a two-fold increased risk compared to males (22% vs 11%, odds ratio [OR] 2.17; 95% CI 1.52 to 3.09). Low body weight was also associated with increased risk of severe rash (P = 0.002), but this association was not significant after adjustment for sex. The association between sex and risk of severe rash was consistent across clinical trials and treatments (vemurafenib monotherapy, vemurafenib plus cobimetinib).

Conclusion

Females had approximately two-fold increased risk of developing severe rash compared to males in clinical trials of vemurafenib alone or in combination with cobimetinib.

Systemic Therapies for Advanced Melanoma

The incidence of metastatic melanoma continues to increase each decade. Although surgical treatment is often curative for localized stage I and stage II disease, the median survival for patients with distant metastases is less than 1 year. The last 2 decades have witnessed a breakthrough in therapeutic options with the development of immune checkpoint inhibitors, small molecule targeted therapy, and oncolytic viral therapy. This article provides an overview of the treatment options available for advanced melanoma, including chemotherapy, targeted therapy, immunotherapy, interleukin-2, and oncolytic viral agents.

What's New in Dermatopathology: Inflammatory Dermatoses

Inflammatory skin diseases encompass a vast array of conditions. The field continues to expand and evolve with resurgence of conditions, through newly recognized medication adverse effects, and via more detailed descriptions of known dermatoses. The importance of clinicopathologic correlation and an up to date knowledge of dermatologic conditions cannot be overstated. This review focuses on an array of recent important developments in the histologic diagnosis of inflammatory conditions that affect the skin.

Cutaneous Side Effects of Targeted Therapy and Immunotherapy for Advanced Melanoma

Melanoma is one of the most fatal cancers, and its incidence is increasing worldwide. Thanks to the better understanding of the molecular mechanisms involved in the pathogenesis of melanoma, recently new targeted agents have been developed. In this article, we review the current state of knowledge of clinical presentation, mechanisms, and management of the most common cutaneous side effects observed during treatment with targeted and immunological therapies approved for advanced melanoma. We include discussion of BRAF/MEK inhibitors and immune-checkpoint inhibitors, notably CTLA-4 and PD-1 inhibitors.

Targeting the MAPK Pathway in RAS Mutant Cancers

Despite decades of extensive drug discovery efforts, there are currently no targeted therapies approved to treat KRAS mutant cancers. In this review, we highlight the challenges and opportunities in targeting KRAS mutant tumors through inhibition of mitogen-activated protein kinase (MAPK) signaling with conformation-specific kinase inhibitors. Through structural analysis and mechanistic studies with BRAF and mitogen-activated protein kinase (MEK) inhibitors, we describe how kinase-dependent and -independent functions of MAPK signaling components regulate KRAS-driven tumorigenesis and how these insights can be used to treat RAS mutant cancers with small molecule kinase inhibitors.

The Role of Human Papillomaviruses and Polyomaviruses in BRAF-Inhibitor Induced Cutaneous Squamous Cell Carcinoma and Benign Squamoproliferative Lesions

Background: Human papillomavirus (HPV) has long been proposed as a cofactor in the pathogenesis of cutaneous squamous cell carcinoma (cSCC). More recently, the striking clinico-pathological features of cSCCs that complicate treatment of metastatic melanoma with inhibitors targeting BRAF mutations (BRAFi) has prompted speculation concerning a pathogenic role for oncogenic viruses. Here, we investigate HPV and human polyomaviruses (HPyV) and correlate with clinical, histologic, and genetic features in BRAFi-associated cSCC.

Materials and Methods: Patients receiving BRAFi treatment were recruited at Barts Health NHS Trust. HPV DNA was detected in microdissected frozen samples using reverse line probe technology and degenerate and nested PCR. HPV immunohistochemistry was performed in a subset of samples. Quantitative PCR was performed to determine the presence and viral load of HPyVs with affinity for the skin (HPyV6, HPyV7, HPyV9, MCPyV, and TSPyV). These data were correlated with previous genetic mutational analysis of H, K and NRAS, NOTCH1/2, TP53, CDKN2A, CARD11, CREBBP, TGFBR1/2. Chromosomal aberrations were profiled using single nucleotide polymorphism (SNP) arrays.

Results: Forty-five skin lesions from seven patients treated with single agent vemurafenib in 2012–2013 were analyzed: 12 cSCC, 19 viral warts (VW), 2 actinic keratosis (AK), 5 verrucous keratosis/other squamoproliferative (VK/SP) lesions, one melanocytic lesion and 6 normal skin samples. Significant histologic features of viral infection were seen in 10/12 (83%) cSCC. HPV DNA was detected in 18/19 (95%) VW/SP, 9/12 (75%) cSCC, 4/5 (80%) SP, and 3/6 (50%) normal skin samples and in 1/12 cases assessed by immunohistochemistry. HPyV was co-detected in 22/30 (73%) of samples, usually at low viral load, with MCPyV and HPyV7 the most common. SNP arrays confirmed low levels of chromosomal abnormality and there was no significant correlation between HPV or HPyV detection and individual gene mutations or overall mutational burden.

Conclusion: Despite supportive clinicopathologic evidence, the role for HPV and HPyV infection in the pathogenesis of BRAFi-induced squamoproliferative lesions remains uncertain. Synergistic oncogenic mechanisms are plausible although speculative. Nonetheless, with the prospect of a significant increase in the adjuvant use of these drugs, further research is justified and may provide insight into the pathogenesis of other BRAFi-associated malignancies.

MAPK Pathway-Targeted Therapies: Care and Management of Unique Toxicities in Patients With Advanced Melanoma

BACKGROUND

Agents targeting the MAPK pathway, including inhibitors of BRAF and MEK, have dramatically transformed the treatment landscape for patients with BRAF-mutant metastatic melanoma. Although generally well tolerated, targeted agents were associated with unique toxicities.
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OBJECTIVES

This article aims to provide nurses with an overview of the key toxicities and associated management strategies of the characteristic adverse event (AE) profile associated with agents targeting the MAPK pathway.
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METHODS

Data from clinical trials evaluating vemurafenib, dabrafenib, trametinib, and cobimetinib were reviewed and summarized along with research on management of AEs identified in clinical trials.
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FINDINGS

The key AEs associated with these agents included pyrexia and cutaneous toxicities. Other notable AEs included arthralgias, ocular toxicities, and cardiac events. Because these agents are administered until progressive disease or unacceptable toxicity, nurses should be aware of management strategies to optimize treatment outcomes.

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.

ESCMID Study Group for Infections in Compromised Hosts (ESGICH) Consensus Document on the safety of targeted and biological therapies: an infectious diseases perspective (Intracellular signaling pathways: tyrosine kinase and mTOR inhibitors)

BACKGROUND

The present review is part of the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) Study Group for Infections in Compromised Hosts (ESGICH) Consensus Document on the safety of targeted and biologic therapies.

AIMS

To review, from an infectious diseases perspective, the safety profile of therapies targeting different intracellular signaling pathways and to suggest preventive recommendations.

SOURCES

Computer-based Medline searches with MeSH terms pertaining to each agent or therapeutic family.

CONTENT

Although BCR-ABL tyrosine kinase inhibitors modestly increase the overall risk of infection, dasatinib has been associated with cytomegalovirus and hepatitis B virus reactivation. BRAF/MEK kinase inhibitors do not significantly affect infection susceptibility. The effect of Bruton tyrosine kinase inhibitors (ibrutinib) among patients with B-cell malignancies is difficult to distinguish from that of previous immunosuppression. However, cases of Pneumocystis jirovecii pneumonia (PCP), invasive fungal infection and progressive multifocal leukoencephalopathy have been occasionally reported. Because phosphatidylinositol-3-kinase inhibitors (idelalisib) may predispose to opportunistic infections, anti-Pneumocystis prophylaxis and prevention strategies for cytomegalovirus are recommended. No increased rates of infection have been observed with venetoclax (antiapoptotic protein Bcl-2 inhibitor). Therapy with Janus kinase inhibitors markedly increases the incidence of infection. Pretreatment screening for chronic hepatitis B virus and latent tuberculosis infection must be performed, and anti-Pneumocystis prophylaxis should be considered for patients with additional risk factors. Cancer patients receiving mTOR inhibitors face an increased incidence of overall infection, especially those with additional risk factors (prior therapies or delayed wound healing).

IMPLICATIONS

Specific preventive approaches are warranted in view of the increased risk of infection associated with some of the reviewed agents.

Management of the cutaneous adverse effects of antimelanoma therapy

The advent of targeted therapy and immunotherapy has revolutionized the management of advanced melanoma. However, these novel therapies are associated with adverse effects (AEs), of which cutaneous toxicities are the most frequently observed. These cutaneous AEs can exert significant morbidity and impact on patient quality of life, hence the recognition and management of AEs is fundamental in preventing interruption or cessation of survival-prolonging treatments. Additionally, knowledge of these AEs are necessary in order for healthcare professionals to counsel patients when starting treatment and in the initiation of AE prophylaxis. The incidence and clinical presentation of the cutaneous toxicities of novel melanoma therapies will be discussed, and treatment guidelines provided.

Incidence and relative risk of cutaneous squamous cell carcinoma with single-agent BRAF inhibitor and dual BRAF/MEK inhibitors in cancer patients: a meta-analysis

BACKGROUND

BRAF inhibitor and dual BRAF/MEK inhibitors have been approved for the treatment of BRAF-mutated melanoma. Cutaneous squamous cell carcinoma (cuSCC) is an adverse event associated with these drugs. The contribution of BRAF inhibitor and dual BRAF/MEK inhibitors to cuSCC are still unknown. We performed this meta-analysis to determine the overall incidence and relative risk of cuSCC in cancer patients treated with these drugs.

RESULTS

A total of 7,442 patients from 24 primary studies were included. The incidences of all-grade and high-grade cuSCC in cancer patients treated with BRAF inhibitor were 12.5% (95% CI: 10.8-14.6%) and 11.6% (95% CI: 9.8-13.8%), and dual BRAF/MEK inhibitors were 3.0% (95% CI: 2.0-4.5%) and 2.8% (95% CI: 1.9-4.0%), respectively. On subgroup analysis and meta-regression, the incidence of cuSCC did not vary with tumor type, study design and specific drug used. The use of single agent BRAF inhibitor significantly increased the risk of developing cuSCC comparing with dual BRAF/MEK inhibitors for all-grade (RR 4.72, 95% CI: 2.42-9.20) and high-grade (RR 4.92, 95% CI: 2.64-9.16) in cancer patients.

MATERIALS AND METHODS

The databases of PubMed, Embase and abstracts published in ASCO proceedings were searched for relevant studies from January 2000 to June 2017. Summary incidences, relative risks (RRs) and 95% confidence intervals (CIs) were calculated by using either random effects or fixed effect models according to the heterogeneity of included studies.

CONCLUSIONS

BRAF inhibitor significantly increases the risk of developing cuSCC compared with dual BRAF/MEK inhibitors in cancer patients. Clinicians should be aware of the risks of cuSCC with the administration of these drugs in cancer patients.

Cutaneous Eruptions in Patients Receiving Immune Checkpoint Blockade: Clinicopathologic Analysis of the Nonlichenoid Histologic Pattern

Cutaneous eruptions are among the most common immune-related adverse events (irAEs) associated with anti-programmed cell death protein 1/programmed cell death ligand 1 therapy, and are often clinically and histologically characterized as lichenoid. Nonlichenoid patterns may also occur and are likely to be encountered by surgical pathologists, given the increasing clinical use of these agents. The purpose of this study is to describe the histopathologic features of nonlichenoid cutaneous irAEs from patients receiving anti-programmed cell death protein 1/programmed cell death ligand 1 therapies for a variety of underlying advanced malignancies. Sixteen patients with 17 biopsied eruptions were included from 2 academic institutions with extensive experience administering and monitoring responses to immune checkpoint blockade as well as treating the potential side effects. Eruptions occurred a median of 10 days (range, 1 d to 11.4 mo) after treatment initiation. Nearly half of specimens demonstrated either a psoriasiform/spongiotic or an urticarial-type reaction pattern on histologic review. Patterns consistent with Grover disease, bullous pemphigoid, and granulomatous dermatitis were also observed. Nearly two-thirds of patients required systemic corticosteroids for treatment of the cutaneous irAE, and 19% of patients discontinued immunotherapy due to their skin eruptions. 75% of patients showed an objective antitumor response. The diverse array of nonlichenoid cutaneous irAE presented here should reflect and inform the scope of histologic patterns encountered by the practicing surgical pathologist. Such eruptions are seen in patients with a variety of underlying tumor types, many of whom ultimately demonstrate a favorable response to immune checkpoint blockade.

BRAF inhibitor-associated cutaneous squamous cell carcinoma: new mechanistic insight, emerging evidence for viral involvement and perspectives on clinical management

Mutations in the BRAF proto-oncogene occur in the majority of cutaneous melanomas. The commonly detected valine (V) to glutamate (E) mutation (V600E) is known to drive melanomagenesis and has thus been the target of two highly selective chemotherapeutic agents: vemurafenib and dabrafenib. While BRAF inhibitor therapy has revolutionized the treatment of metastatic melanoma, unanticipated cutaneous toxicities, including the development of cutaneous squamous cell carcinomas (cSCCs), are frequently reported and hinder therapeutic durability. However, the mechanisms by which BRAF inhibitors induce cutaneous neoplasms are poorly understood, thus posing a challenge for specific therapies. In this review, we summarize the clinical and molecular profiles of BRAF inhibitor-associated cSCCs, with a focus on factors that may contribute to disease pathogenesis. In particular, we discuss the emerging evidence pointing towards viral involvement in BRAF inhibitor-induced cutaneous neoplasms and offer new perspectives on future therapeutic interventions. Continued clinical and mechanistic studies along this line will not only allow for better understanding of the pathogenic progression of BRAF inhibitor-induced cSCCs, but will also lead to development of new therapeutic and preventative options for patients receiving targeted cancer therapy.

Bisarylureas Based on 1H-Pyrazolo[3,4-d]pyrimidine Scaffold as Novel Pan-RAF Inhibitors with Potent Anti-Proliferative Activities: Structure-Based Design, Synthesis, Biological Evaluation and Molecular Modelling Studies

RAF (Ras activating factor) kinases are important and attractive targets for cancer therapy. With the aim of discovering RAF inhibitors that bind to DFG-out inactive conformation created by the movement of Asp-Phe-Gly (DFG), we conducted structure-based drug design using the X-ray cocrystal structures of BRAF (v-raf murine sarcoma viral oncogene homolog B1), starting from bisarylurea derivative based on 1H-pyrazolo[3,4-d]pyrimidine scaffold 1a. Most of the synthesized compounds showed good to excellent inhibitory activities against BRAF^V600E kinase, possessed moderate to potent anti-proliferative activities against four tumor cell lines (A375, HT-29, PC-3 and A549) and good selectivity towards cancer cells rather normal cells (Madin-Darby canine kidney, MDCK). The most promising compound, 1v, exhibited potent inhibitory activity against not only BRAF^V600E (half maximal inhibitory concentration, IC₅₀ = 23.6 nM) but also wild-type BRAF (IC₅₀ = 51.5 nM) and C-RAF (IC₅₀ = 8.5 nM), and effective cellular anti-proliferative activities against A375, HT-29, PC-3 and A549 cell lines as well as a very good selectivity profile. Moreover, compound 1v mainly arrested the A375 cell line in the G0/G1 stage, and showed significant suppression of MEK (mitogen-activated protein kinase kinase) phosphorylation in A375 and HT-29 cell lines. Taken together, the optimal compound 1v showed excellent in vitro potency as a pan-RAF inhibitor. In addition, the promise of compound 1v was further confirmed by molecular dynamics simulation and binding free energy calculations.

Rational design, synthesis, and biological evaluation of Pan-Raf inhibitors to overcome resistance

We describe the design and characterization of a series of pyrimidine scaffolds as Pan-Raf inhibitors, which may overcome the resistance associated with current BRaf^V600E inhibitors.

Preclinical efficacy of a RAF inhibitor that evades paradoxical MAPK pathway activation in protein kinase BRAF-mutant lung cancer

Oncogenic activation of protein kinase BRAF drives tumor growth by promoting mitogen-activated protein kinase (MAPK) pathway signaling. Because oncogenic mutations in BRAF occur in ∼2-7% of lung adenocarcinoma (LA), BRAF-mutant LA is the most frequent cause of BRAF-mutant cancer mortality worldwide. Whereas most tumor types harbor predominantly the BRAF^V600E-mutant allele, the spectrum of BRAF mutations in LA includes BRAF^V600E (∼60% of cases) and non-V600E mutant alleles (∼40% of cases) such as BRAF^G469A and BRAF^G466V The presence of BRAF^V600E in LA has prompted clinical trials testing selective BRAF inhibitors such as vemurafenib in BRAF^V600E-mutant patients. Despite promising clinical efficacy, both innate and acquired resistance often result from reactivation of MAPK pathway signaling, thus limiting durable responses to the current BRAF inhibitors. Further, the optimal therapeutic strategy to block non-V600E BRAF-mutant LA remains unclear. Here, we report the efficacy of the Raf proto-oncogene serine/threonine protein kinase (RAF) inhibitor, PLX8394, that evades MAPK pathway reactivation in BRAF-mutant LA models. We show that PLX8394 treatment is effective in both BRAF^V600E and certain non-V600 LA models, in vitro and in vivo. PLX8394 was effective against treatment-naive BRAF-mutant LAs and those with acquired vemurafenib resistance caused by an alternatively spliced, truncated BRAF^V600E that promotes vemurafenib-insensitive MAPK pathway signaling. We further show that acquired PLX8394 resistance occurs via EGFR-mediated RAS-mTOR signaling and is prevented by upfront combination therapy with PLX8394 and either an EGFR or mTOR inhibitor. Our study provides a biological rationale and potential polytherapy strategy to aid the deployment of PLX8394 in lung cancer patients.

Chemically Linked Vemurafenib Inhibitors Promote an Inactive BRAFV600E Conformation

The BRAF kinase, within the mitogen activated protein kinase (MAPK) signaling pathway, harbors activating mutations in about half of melanomas and to a significant extent in many other cancers. A single valine to glutamic acid substitution at residue 600 (BRAF^V600E) accounts for about 90% of these activating mutations. While BRAF^V600E-selective small molecule inhibitors, such as debrafenib and vemurafenib, have shown therapeutic benefit, almost all patients develop resistance. Resistance often arises through reactivation of the MAPK pathway, typically through mutation of upstream RAS, downstream MEK, or splicing variants. RAF kinases signal as homo- and heterodimers, and another complication associated with small molecule BRAF^V600E inhibition is drug-induced allosteric activation of a wild-type RAF subunit (BRAF or CRAF) of the kinase dimer, a process called "transactivation" or "paradoxical activation." Here, we used BRAF^V600E and vemurafenib as a model system to develop chemically linked kinase inhibitors to lock RAF dimers in an inactive conformation that cannot undergo transactivation. This structure-based design effort resulted in the development of Vem-BisAmide-2, a compound containing two vemurafenib molecules connected by a bis amide linker. We show that Vem-BisAmide-2 has comparable inhibitory potency as vemurafenib to BRAF^V600E both in vitro and in cells but promotes an inactive dimeric BRAF^V600E conformation unable to undergo transactivation. The crystal structure of a BRAF^V600E/Vem-BisAmide-2 complex and associated biochemical studies reveal the molecular basis for how Vem-BisAmide-2 mediates selectivity for an inactive over an active dimeric BRAF^V600E conformation. These studies have implications for targeting BRAF^V600E/RAF heterodimers and other kinase dimers for therapy.

Lesions With an Epidermal Hyperplastic Pattern: Morphologic Clues in the Differential Diagnosis

In this report, we review the most common entities that show a epidermal hyperplastic pattern in the biopsy. These entities include inflammatory, reactive, infectious, hamartomatous, and tumoral conditions, each with a very different prognosis. Therefore, an approach based on the classic "patterns and clues" tools used in dermatopathology can bring a lot of information to the dermatopathologist or the general pathologist evaluating these lesions.