Cutaneous side effects of inhibitors of the RAS/RAF/MEK/ERK signalling pathway and their management

Cutaneous toxicities of mitogen-activated protein kinase inhibitors in children and young adults with neurofibromatosis-1

PURPOSE

Neurofibromatosis type 1 (NF1) is an autosomal dominant disorder which commonly causes neoplasms leading to disfigurement or dysfunction. Mitogen-activated protein kinase inhibitors (MEKi) are generally well-tolerated treatments which target neural tumor progression in patients with NF1. However, cutaneous adverse events (CAEs) are common and may hinder patients' abilities to remain on treatment, particularly in children. We aim to characterize CAEs secondary to MEKi treatment in pediatric and young adult patients with NF1.

METHODS

We reviewed institutional medical records of patients under 30 years with a diagnosis of "NF1," "NF2," or "other neurofibromatoses" on MEKi therapy between January 1, 2019 and June 1, 2022. We recorded the time-to-onset, type, and distribution of CAEs, non-cutaneous adverse events (AEs), AE management, and tumor response.

RESULTS

Our cohort consisted of 40 patients with NF1 (median age, 14 years). Tumor types included low-grade gliomas (51%) and plexiform neurofibromas (38%). MEKi used included selumetinib (69%), trametinib (25%), and mirdametinib (6%). A total of 74 CAEs occurred, with 28 cases of acneiform rash (38%). Other common CAEs were paronychia, seborrheic dermatitis, eczema, xerosis, and oral mucositis. The most common treatments included oral antibiotics and topical corticosteroids. Most patients had clinical (stable or improved) tumor response (71%) while 29% had tumor progression while on a MEKi. There was no significant association between CAE presence and tumor response (p = 0.39).

CONCLUSIONS

Improvement in characterization of MEKi toxicities and their management is important to develop treatment guidelines for pediatric and young adult patients with NF1 on MEKi therapy.

Oral Adverse Events Associated with BRAF and MEK Inhibitors in Melanoma Treatment: A Narrative Literature Review

BACKGROUND

Melanoma cancer represents the most lethal type of skin cancer originating from the malignant transformation of melanocyte cells. Almost 50% of melanomas show the activation of BRAF mutations. The identification and characterization of BRAF mutations led to the development of specific drugs that radically changed the therapeutic approach to melanoma.

METHODS

We conducted a narrative review of the literature according to a written protocol before conducting the study. This article is based on previously conducted studies. We identified articles by searching electronic databases (Medline, Google Scholar and PubMed). We used a combination of "melanoma", "Braf-Mek inhibitors", " targeted therapy" and "oral side effects".

RESULTS

Eighteen studies were reported in this article showing the relationship between the use of targeted therapy in melanoma cancer and the development of oral side effects, such as mucositis, hyperkeratosis and cellular proliferation.

CONCLUSION

Targeted therapy plays an important role in the treatment of melanoma cancer, showing a notable increase in response rate, prolonged progression-free survival and overall survival in BRAF-mutated melanoma patients. Oral side effects represent a common finding over the course of treatment. However, these adverse effects can be easily managed in a multidisciplinary approach involving collaboration between medical oncologists and dental doctors.

Low-grade serous ovarian cancer: expert consensus report on the state of the science

Compared with high-grade serous carcinoma, low-grade serous carcinoma of the ovary or peritoneum is a less frequent epithelial ovarian cancer type that is poorly sensitive to chemotherapy and affects younger women, many of whom endure years of ineffective treatments and poor quality of life. The pathogenesis of this disease and its management remain incompletely understood. However, recent advances in the molecular characterization of the disease and identification of novel targeted therapies with activity in low-grade serous carcinoma offer the promise of improved outcomes. To update clinicians regarding recent scientific and clinical trial advancements and discuss unanswered questions related to low-grade serous carcinoma diagnosis and treatment, a panel of experts convened for a workshop in October 2022 to develop a consensus document addressing pathology, translational research, epidemiology and risk, clinical management, and ongoing research. In addition, the patient perspective was discussed. The recommendations developed by this expert panel-presented in this consensus document-will guide practitioners in all settings regarding the clinical management of women with low-grade serous carcinoma and discuss future opportunities to improve research and patient care.

Early experience with targeted therapy as a first-line adjuvant treatment for pediatric low-grade glioma

OBJECTIVE

Pediatric low-grade gliomas (pLGGs) frequently exhibit dysregulation of the mitogen-activated protein kinase (MAPK) pathway. Targeted therapies, including mutant BRAF inhibitors (dabrafenib) and MEK inhibitors (trametinib), have shown promise in patients in whom conventional chemotherapy has failed. However, few studies have investigated the use of targeted therapy as a first-line treatment for pLGG. Here, the authors reviewed their institutional experience with using a personalized medicine approach to patients with newly diagnosed pLGGs.

METHODS

All pediatric patients at the authors' institution who had been treated with dabrafenib or trametinib for pLGG without first receiving conventional chemotherapy or radiation were retrospectively reviewed. Demographic, clinical, and radiological data were collected.

RESULTS

Eight patients underwent targeted therapy as a first-line treatment for pLGG. Five patients had a BRAF alteration (1 with a BRAFV600E mutation, 4 with a KIAA1549:BRAF fusion), and 3 patients had an NF1 mutation. One of the 8 patients was initially treated with dabrafenib, and trametinib was added later. Seven patients were initially treated with trametinib; of these, 2 later transitioned to dual therapy, whereas 5 continued with trametinib monotherapy. Six patients (75%) demonstrated a partial response to therapy during their treatment course, whereas stable disease was identified in the remaining 2 patients (25%). One patient experienced mild disease progression after completing a course of trametinib monotherapy, but ultimately stabilized after a period of close observation. Another patient experienced tumor progression while on dabrafenib, but subsequently responded to dual therapy with dabrafenib and trametinib. The most common adverse reactions to targeted therapy were cutaneous toxicity (100%) and diarrhea (50%).

CONCLUSIONS

Targeted therapies have the potential to become a standard treatment option for pLGG due to their favorable toxicity profile and oral route of administration. This case series provides preliminary evidence that targeted therapies can induce an early disease response as a first-line adjuvant treatment; however, large-scale studies are required to assess long-term durability and safety.

Assessment of Skin Toxicity in an in Vitro Reconstituted Human Epidermis Model Using Deep Learning

Skin toxicity is a common safety concern associated with drugs that inhibit epidermal growth factor receptors as well as other targets involved in epidermal growth and differentiation. Recently, the use of a three-dimensional reconstructed human epidermis model enabled large-scale drug screening and showed potential for predicting skin toxicity. Although a decrease in epidermal thickness was often observed when the three-dimensional reconstructed tissues were exposed to drugs causing skin toxicity, the thickness evaluation of epidermal layers from a pathologist was subjective and not easily reproducible or scalable. In addition, the subtle differences in thickness among tissues, as well as the large number of samples tested, made cross-study comparison difficult when a manual evaluation strategy was used. The current study used deep learning and image-processing algorithms to measure the viable epidermal thickness from multiple studies and found that the measured thickness was not only significantly correlated with a pathologist's semi-quantitative evaluation but was also in close agreement with the quantitative measurement performed by pathologists. Moreover, a sensitivity of 0.8 and a specificity of 0.75 were achieved when predicting the toxicity of 18 compounds with clinical observations with these epidermal thickness algorithms. This approach is fully automated, reproducible, and highly scalable. It not only shows reasonable accuracy in predicting skin toxicity but also enables cross-study comparison and high-throughput compound screening.

Adverse Effects of Vemurafenib on Skin Integrity: Hyperkeratosis and Skin Cancer Initiation Due to Altered MEK/ERK-Signaling and MMP Activity

The BRAF inhibitor vemurafenib, approved for treating patients with BRAF V600E-mutant and unresectable or metastatic melanomas, rapidly induces cutaneous adverse events, including hyperkeratotic skin lesions and cutaneous squamous cell carcinomas (cSCC). To determine, how vemurafenib would provoke these adverse events, we utilized long-term in vitro skin equivalents (SEs) comprising epidermal keratinocytes and dermal fibroblasts in their physiological environment. We inserted keratinocytes with different genetic background [normal keratinocytes: NHEK, HaCaT (p53/mut), and HrasA5 (p53/mut+Hras/mut)] to analyze effects depending on the stage of carcinogenesis. We now show that vemurafenib activates MEK-ERK signaling in both, keratinocytes, and fibroblasts in vitro and in the in vivo-like SEs. As a consequence, vemurafenib does not provide a growth advantage but leads to a differentiation phenotype, causing accelerated differentiation and hyperkeratosis in the NHEK and normalized stratification and cornification in the transformed keratinocytes. Although all keratinocytes responded very similarly to vemurafenib in their expression profile, particularly with a significant induction of MMP1 and MMP3, only the HrasA5 cells revealed a vemurafenib-dependent pathophysiological shift to tumor progression, i.e., the initiation of invasive growth. This was shown by increased proteolytic activity allowing for penetration of the basement membrane and invasion into the disrupted underlying matrix. Blocking MMP activity, by the addition of ilomastat, prevented invasion with all corresponding degradative activities, thus substantiating that the RAS-RAF-MEK-ERK/MMP axis is the most important molecular basis for the rapid switch towards tumorigenic conversion of the HrasA5 keratinocytes upon vemurafenib treatment. Finally, cotreatment with vemurafenib and the MEK inhibitor cobimetinib prevented MEK-ERK hyperactivation and with that abolished both, the epidermal differentiation and the tumor invasion phenotype. This suggests that both cutaneous adverse events are under direct control of vemurafenib-dependent MEK-ERK hyperactivation and confirms the dependence on preexisting genetic alterations of the skin keratinocytes that determine the basis towards induction of tumorigenic progression.

Efficacy and safety of anti-epidermal growth factor receptor agents for the treatment of oesophageal cancer: a systematic review and meta-analysis

OBJECTIVES

Despite remarkable advances in the treatment of oesophageal cancer (OC), the role of antiepidermal growth factor receptor (anti-EGFR) agents in treating OC remains controversial. Herein, a systematic review and meta-analysis were conducted to elucidate the efficacy and safety of anti-EGFR agents in patients with OC.

DESIGN

Meta-analysis of randomised controlled trials (RCTs) identified by searching the PubMed, Embase, Web of Science, ClinicalTrials.gov, Cochrane Library, Chinese Biology Medicine, China National Knowledge Infrastructure and Wanfang Data Knowledge Service Platform databases from inception to December 2019. We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

SETTING

RCTs from any country and healthcare setting.

PARTICIPANTS

Patients with OC.

INTERVENTIONS

Combination therapy with anti-EGFR agents and conventional treatments versus conventional treatments alone in patients with OC.

PRIMARY AND SECONDARY OUTCOME MEASURES

Overall survival (OS) and progression-free survival (PFS) were primary outcome measures, and objective response rate (ORR), disease control rate (DCR) and treatment toxicities were secondary outcome measures.

RESULTS

In total, 25 RCTs comprising 3406 patients with OC were included. Overall, anti-EGFR treatment significantly improved the OS (HR: 0.81, 95% CI 0.74 to 0.89, p<0.00001), ORR (relative risk (RR): 1.33, 95% CI 1.16 to 1.52, p<0.0001) and DCR (RR: 1.22, 95% CI 1.11 to 1.34, p<0.0001) but not PFS (HR: 0.91, 95% CI 0.76 to 1.08, p=0.26). Anti-EGFR treatment was significantly associated with higher incidences of myelosuppression, diarrhoea, acne-like rash and hypomagnesaemia.

CONCLUSIONS

Overall, anti-EGFR agents have positive effects on OS, the ORR and DCR in OC. However, considering the high incidence of adverse effects, such as myelosuppression, diarrhoea, acne-like rashes and hypomagnesaemia, careful monitoring of patients with OC is recommended during anti-EGFR treatment.

TRIAL REGISTRATION NUMBER

CRD42020169230.

A kinome-wide RNAi screen identifies ERK2 as a druggable regulator of Shank3 stability

Neurons are sensitive to changes in the dosage of many genes, especially those regulating synaptic functions. Haploinsufficiency of SHANK3 causes Phelan-McDermid syndrome and autism, whereas duplication of the same gene leads to SHANK3 duplication syndrome, a disorder characterized by neuropsychiatric phenotypes including hyperactivity and bipolar disorder as well as epilepsy. We recently demonstrated the functional modularity of Shank3, which suggests that normalizing levels of Shank3 itself might be more fruitful than correcting pathways that function downstream of it for treatment of disorders caused by alterations in SHANK3 dosage. To identify upstream regulators of Shank3 abundance, we performed a kinome-wide siRNA screen and identified multiple kinases that potentially regulate Shank3 protein stability. Interestingly, we discovered that several kinases in the MEK/ERK2 pathway destabilize Shank3 and that genetic deletion and pharmacological inhibition of ERK2 increases Shank3 abundance in vivo. Mechanistically, we show that ERK2 binds Shank3 and phosphorylates it at three residues to promote its poly-ubiquitination-dependent degradation. Altogether, our findings uncover a druggable pathway as a potential therapeutic target for disorders with reduced SHANK3 dosage, provide a rich resource for studying Shank3 regulation, and demonstrate the feasibility of this approach for identifying regulators of dosage-sensitive genes.

How to make an undruggable enzyme druggable: lessons from ras proteins

Significant advances have been made toward discovering allosteric inhibitors for challenging drug targets such as the Ras family of membrane-associated signaling proteins. Malfunction of Ras proteins due to somatic mutations is associated with up to a quarter of all human cancers. Computational techniques have played critical roles in identifying and characterizing allosteric ligand-binding sites on these proteins, and to screen ligand libraries against those sites. These efforts, combined with a wide range of biophysical, structural, biochemical and cell biological experiments, are beginning to yield promising inhibitors to treat malignancies associated with mutated Ras proteins. In this chapter, we discuss some of these developments and how the lessons learned from Ras might be applied to similar other challenging drug targets.

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.

Vemurafenib acts as an aryl hydrocarbon receptor antagonist: Implications for inflammatory cutaneous adverse events

BACKGROUND

In recent years, the BRAF inhibitor vemurafenib has been successfully established in the therapy of advanced melanoma. Despite its superior efficacy, the use of vemurafenib is limited by frequent inflammatory cutaneous adverse events that affect patients' quality of life and may lead to dose reduction or even cessation of anti-tumor therapy. To date, the molecular and cellular mechanisms of vemurafenib-induced rashes have remained largely elusive.

METHODS

In this study, we deployed immunohistochemistry, RT-qPCR, flow cytometry, lymphocyte activation tests, and different cell-free protein-interaction assays.

RESULTS

We here demonstrate that vemurafenib inhibits the downstream signaling of the canonical pathway of aryl hydrocarbon receptor (AhR) in vitro, thereby inducing the expression of proinflammatory cytokines (eg, TNF) and chemokines (eg, CCL5). In line with these results, we observed an impaired expression of AhR-regulated genes (eg, CYP1A1) and an upregulation of the corresponding proinflammatory genes in vivo. Moreover, results of lymphocyte activation tests showed the absence of drug-specific T cells in respective patients.

CONCLUSION

Taken together, we obtained no hint of an underlying sensitization against vemurafenib but found evidence suggesting that vemurafenib enhances proinflammatory responses by inhibition of canonical AhR signaling. Our findings contribute to our understanding of the central role of the AhR in skin inflammation and may point toward a potential role for topical AhR agonists in supportive cancer care.

Targeted therapy in oncology patients and skin: Pharmaceutical and dermocosmetic management

BACKGROUND

Numerous oncology patients who receive targeted therapy suffer from the skin adverse effects induced. Novel agents, that is tyrosine kinase inhibitors and RAS-RAF-MEK-ERK pathway, have given good results in patient survival while decreasing the systemic toxicities in comparison to conventional cytotoxic chemotherapy, but are also related to skin adverse effects.

AIMS

In this article, we highlighted the importance of specific pharmaceutical and dermocosmetic management of the untoward events of targeted therapy.

CONCLUSION

The combination of Oncodermatology, Psychodermatology, Cosmetic Dermatology, Cosmetic Science, Dermatopharmacology and Aesthetic Science can offer a lot for the prevention or early relief of the cutaneous adverse effects in oncology patients receiving targeted therapy.

AKT and ERK dual inhibitors: The way forward?

Phosphatidylinositol 3-kinase (PI3K)/AKT pathway regulates cell growth, proliferation, survival, mobility and invasion. Mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) pathway is also an important mitogenic signaling pathway involved in various cellular progresses. AKT, also named protein kinase B (PKB), is a primary mediator of the PI3K signaling pathway; and ERK at the end of MAPK signaling is the unique substrate and downstream effector of mitogen-activated protein/extracellular signal-regulated kinase (MEK). The AKT and ERK signaling are both aberrantly activated in a wide range of human cancers and have long been targeted for cancer therapy, but the clinical benefits of these targeted therapies have been limited due to complex cross-talk. Novel strategies, such as AKT/ERK dual inhibitors, may be needed.

Correlation Between Raf/MEK/ERK Signaling Pathway and Clinicopathological Features and Prognosis for Patients With Breast Cancer Having Axillary Lymph Node Metastasis

Objective:

This study aims to investigate the correlations between rapidly accelerated fibrosarcoma/mitogen-activated protein kinase kinase (MEK)/extracellular signal-regulated kinase signaling pathway and clinicopathological features and prognosis for patients with breast cancer having axillary lymph node metastasis.

Methods:

A total of 118 breast cancer tissues with axillary lymph node metastasis (axillary lymph node metastasis group), 150 breast cancer tissues with non-axillary lymph node metastasis (non-axillary lymph node metastasis group), and 216 normal breast tissues (normal group) were enrolled in this study. The messenger RNA and protein expressions of rapidly accelerated fibrosarcoma, MEK, extracellular signal-regulated kinase, and their phosphorylated (p-) proteins were examined by reverse transcriptase quantitative polymerase chain reaction and immunohistochemistry, respectively. All patients received a 1-year follow-up, and the clinical follow-up data were collected. The multiple factors on the prognosis of patients with breast cancer having axillary lymph node metastasis were tested by Cox regression analysis.

Results:

The messenger RNA expressions of rapidly accelerated fibrosarcoma, MEK, and extracellular signal-regulated kinase and positive rates of rapidly accelerated fibrosarcoma, MEK, phosphorylated MEK, extracellular signal-regulated kinase, and p-extracellular signal-regulated kinase in the axillary lymph node metastasis group were higher than in the non-axillary lymph node metastasis and normal groups (all P < .05). The protein expressions of rapidly accelerated fibrosarcoma, MEK, phosphorylated MEK, extracellular signal-regulated kinase, and p-extracellular signal-regulated kinase were associated with tumor size, clinical stage, and axillary lymph node metastasis number (all P < .05). Rapidly accelerated fibrosarcoma, MEK, and extracellular signal-regulated kinase expressions were significantly correlated with the prognosis of patients with breast cancer (all P < .05). Patients with BC having positive rapidly accelerated fibrosarcoma, MEK, phosphorylated MEK, extracellular signal-regulated kinase, and phosphorylated ERK expressions had a higher survival rate than patients with BC having the negative ones (all P < .05). Rapidly accelerated fibrosarcoma and extracellular signal-regulated kinase protein expressions, clinical stage, pathological grade, and axillary lymph node metastasis number were independent prognostic factors in patients with breast cancer having axillary lymph node metastasis (all P < .05).

Conclusion:

Our study proved that rapidly accelerated fibrosarcoma/MEK/extracellular signal-regulated kinase signaling pathway is significantly correlated with the clinicopathological features and prognosis for patients with BC having axillary lymph node metastasis. Rapidly accelerated fibrosarcoma and extracellular signal-regulated kinase protein expressions are independent prognostic factors for patients with breast cancer having axillary lymph node metastasis.

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.

The risk of dermatological toxicities of combined BRAF and MEK inhibition versus BRAF inhibition alone in melanoma patients: a systematic review and meta-analysis

BACKGROUND

This meta-analysis was conducted to assess the risk of dermatological toxicities of combined BRAF and MEK inhibition versus BRAF inhibition alone in melanoma patients.

METHODS

We considered relevant prospective randomized phase I, II, and III trials of melanoma patients on the combined BRAF and MEK inhibition versus BRAF inhibition, describing events of rash, photosensitivity reaction (PR), hyperkeratosis (HK), alopecia, cutaneous squamous-cell carcinom(cSCC), skin papilloma(SP), pruritus, and hand-foot syndrome(HFS), as eligible for inclusion.

RESULTS

Eight trials comprising 3163 patients were included in the meta-analysis. The relative risks(RRs) of developing all-grade rash with combined BRAF and MEK inhibition versus BRAF inhibition was 1.59 (95%CI, 1.35-1.86, p < 0.00001), HK 0.33(95%CI, 0.16-0.66, p = 0.002), SP 0.09(95%CI, 0.04-0.24, p < 0.00001), alopecia 0.30(95%CI, 0.19-0.48, p < 0.00001), cSCC 0.23(95%CI, 0.17-0.31, p < 0.00001), HFS 0.18(95%CI, 0.13-0.26, p < 0.00001) and PR 0.40(95%CI, 0.26-0.61, p < 0.0001), while the RRs of high-grade dermatological toxicities from all included trials were: rash 0.54(95%CI, 0.20-1.43, p = 0.21), HK 0.18(95%CI, 0.06-0.53, p = 0.002), SP 0.14(95%CI, 0.02-1.16, p = 0.07), alopecia 0.72(95%CI, 0.14-3.62, p = 0.69), cSCC 0.23(95%CI, 0.17-0.33, p < 0.00001), HFS 0.40(95%CI, 0.08-2.06, p = 0.27), and PR 0.14(95%CI, 0.04-0.51, p = 0.003), respectly.

CONCLUSION

Our analysis of data has demonstrated that combined BRAF and MEK inhibitor-based treatment is associated with an increased risk of all-grade rash and a decreased risk of all-grade and high-grade HK, SP, alopecia, cSCC, HFS, and PR compared with single BRAF inhibitor alone in melanoma patients. Appropriate prevention and management are recommended.

Cutaneous side effects of molecularly targeted therapies for the treatment of solid tumors

Background

Currently, molecularly targeted drugs are part of the therapeutic arsenal for the treatment of many neoplasms and are responsible for improvements in the quality of life and survival of patients. Although they act on proteins and components within biochemical pathways that are expressed to a greater extent in neoplastic cells, these drugs can also interfere with the activity of normal cells.

Scope

This article reviews the cutaneous side effects of main molecularly targeted cancer therapies for solid tumors.

Findings

The use of these drugs causes side effects, and the skin is one of the most commonly affected organs. In this literature review, we discuss the adverse cutaneous effects caused by molecularly targeted drugs.

Conclusion

The identification of these reactions is important to both dermatologists and oncologists so that they properly diagnose the reaction and administer adequate treatment, which would allow greater adherence to the oncological treatment and improve patients’ quality of life.

Targeting ERK, an Achilles' Heel of the MAPK pathway, in cancer therapy

The mitogen-activated protein kinases (MAPK) pathway, often known as the RAS-RAF-MEK-ERK signal cascade, functions to transmit upstream signals to its downstream effectors to regulate physiological process such as cell proliferation, differentiation, survival and death. As the most frequently mutated signaling pathway in human cancer, targeting the MAPK pathway has long been considered a promising strategy for cancer therapy. Substantial efforts in the past decades have led to the clinical success of BRAF and MEK inhibitors. However, the clinical benefits of these inhibitors are compromised by the frequently occurring acquired resistance due to cancer heterogeneity and genomic instability. This review briefly introduces the key protein kinases involved in this pathway as well as their activation mechanisms. We also generalize the correlations between mutations of MAPK members and human cancers, followed by a summarization of progress made on the development of small molecule MAPK kinases inhibitors. In particular, this review highlights the potential advantages of ERK inhibitors in overcoming resistance to upstream targets and proposes that targeting ERK kinase may hold a promising prospect for cancer therapy.

The incidence and management of cutaneous adverse events of the epidermal growth factor receptor inhibitors

Overexpression of the epidermal growth factor receptor (EGFR) is found in many cancers, including those of the head and neck area, non-small-cell lung cancer, and colorectal, cervical, prostate, breast, ovary, stomach, and pancreatic cancer. The EGFR inhibitors are used at present in the treatment of such cancers. Skin lesions that develop during and after cancer treatment may be due to specific cytostatics, molecular-targeted drugs, radiation therapy, complementary therapy, or the cancer itself, and hence knowledge is essential to distinguish between them. The mechanism through which skin toxicity arises during treatment with EGFR inhibitors is not well known, but seems to be due to the modification of the RAS/RAF/MEK/ERK signal path associated with its activation, which results in the similarity between the adverse effects of EGFR inhibitors and the treatment of melanoma with BRAF and MEK inhibitors. The most common side effects are pruritus, xerosis, papulopustular rash, hand-foot skin reaction, alopecia and dystrophy of the hair, and paronychia. This work presents options for prevention and suggestions for managing these adverse events, which are of importance in the care of patients undergoing oncological treatment.

Management of intracranial melanomas in the era of precision medicine

Melanoma is the most lethal of skin cancers, in part because of its proclivity for rapid and distant metastasis. It is also potentially the most neurotropic cancer in terms of probability of CNS metastasis from the primary lesion. Despite surgical resection and radiotherapy, prognosis remains guarded for patients with brain metastases. Over the past five years, a new domain of personalized therapy has emerged for advanced melanoma patients with the introduction of BRAF and other MAP kinase pathway inhibitors, immunotherapy, and combinatory therapeutic strategies. By targeting critical cellular signaling pathways and unleashing the adaptive immune response against tumor antigens, a subset of melanoma patients have demonstrated remarkable responses to these treatments. Over time, acquired resistance to these modalities inexorably develops, providing new challenges to overcome. We review the rapidly evolving terrain for intracranial melanoma treatment, address likely and potential mechanisms of resistance, as well as evaluate promising future therapeutic approaches currently under clinical investigation.

A Novel Spectroscopically Determined Pharmacodynamic Biomarker for Skin Toxicity in Cancer Patients Treated with Targeted Agents

Raman spectroscopy is a noninvasive and label-free optical technique that provides detailed information about the molecular composition of a sample. In this study, we evaluated the potential of Raman spectroscopy to predict skin toxicity due to tyrosine kinase inhibitors treatment. We acquired Raman spectra of skin of patients undergoing treatment with MEK, EGFR, or BRAF inhibitors, which are known to induce severe skin toxicity; for this pilot study, three patients were included for each inhibitor. Our algorithm, based on partial least squares-discriminant analysis (PLS-DA) and cross-validation by bootstrapping, discriminated to variable degrees spectra from patient suffering and not suffering cutaneous adverse events. For MEK and EGFR inhibitors, discriminative power was more than 90% in the viable epidermis skin layer; whereas for BRAF inhibitors, discriminative power was 71%. There was a 81.5% correlation between blood drug concentration and Raman signature of skin in the case of EGFR inhibitors and viable epidermis skin layer. Our results demonstrate the power of Raman spectroscopy to detect apparition of skin toxicity in patients treated with tyrosine kinase inhibitors at levels not detectable via dermatological inspection and histological evaluation. Cancer Res; 77(2); 557-65. ©2016 AACR.

Prospective Case Series of Cutaneous Adverse Effects Associated With Dabrafenib and Trametinib

Background:

Dabrafenib, a novel selective small-molecule inhibitor of BRAF, has been shown to increase overall survival in patients with unresectable metastatic melanoma harboring the BRAF V600E mutation. The development of resistance has led to combination therapy with selective MEK inhibitor trametinib. Compared with vemurafenib, dabrafenib is a more recent BRAF inhibitor approved by the Food and Drug Administration in May 2013 for metastatic melanoma; fewer data are available in the current literature regarding cutaneous toxicity.

Objectives:

We sought to present additional cutaneous side effects of dabrafenib and trametinib and follow their evolution and management.

Methods:

We carried out a prospective study of 14 patients treated with dabrafenib alone or with trametinib. Patients were followed every 4 weeks, and we collected detailed cutaneous symptoms, photos, and biopsy specimens.

Results:

All patients presented with at least 1 adverse skin reaction. The mean duration of treatment was 24 weeks. The most common adverse effect was papillomas (7/14), followed by palmoplantar hyperkeratosis (5/14), alopecia (5/14), and seborrheic dermatitis-like eruption (2/14). Three patients who received trametinib developed an acneiform eruption (3/5). One patient developed a keratoacanthoma-like squamous cell carcinoma. Side effects presented as early as 2 weeks after starting therapy, with a mean time of onset of 9 weeks.

Conclusion:

Selective BRAF inhibitor dabrafenib and MEK inhibitor trametinib are associated with multiple skin adverse effects. Given their recent approval and the potential for malignant lesions to develop on treatment, awareness of potential adverse effects and their management is necessary.

Cutaneous manifestations of nontargeted and targeted chemotherapies

Care of the oncologic patient requires an integral understanding of the adverse reactions of chemotherapy. With the advent of targeted agents and immunomodulating therapies, reactions to these newer treatments are of clinical interest. Cutaneous side effects of chemotherapeutic agents, including toxic erythema and mucositis, are common and may require cessation of treatment if associated with discomfort, superinfection, or negative impact on quality of life. This article reviews the cutaneous adverse reactions and treatment options of both conventional cytotoxic chemotherapeutic agents and newer targeted, multikinase inhibitors and immunomodulating therapies. An understanding of possible cutaneous reactions by all providers involved in the care of the oncologic patient is critical for prompt recognition, allowing for appropriate treatment and referral to dermatologists when necessary.

Integrated analysis of the miRNA, gene and pathway regulatory network in gastric cancer

Gastric cancer is one of the most common malignant tumors worldwide; however, the efficacy of clinical treatment is limited. MicroRNAs (miRNAs) are a class of small non-coding RNAs that have been reported to play a key role in the development of cancer. They also provide novel candidates for targeted therapy. To date, in-depth studies on the molecular mechanisms of gastric cancer involving miRNAs are still absent. We previously reported that 5 miRNAs were identified as being significantly increased in gastric cancer, and the role of these miRNAs was investigated in the present study. By using bioinformatics tools, we found that more than 4,000 unique genes are potential downstream targets of gastric cancer miRNAs, and these targets belong to the protein class of nucleic acid binding, transcription factor, enzyme modulator, transferase and receptor. Pathway mapping showed that the targets of gastric cancer miRNAs are involved in the MAPK signaling pathway, pathways in cancer, the PI3K-Akt signaling pathway, the HTLV-1 signaling pathway and Ras signaling pathway, thus regulating cell growth, differentiation, apoptosis and metastasis. Analysis of the pathways related to miRNAs may provides potential drug targets for future therapy of gastric cancer.

Recent advances in the treatment of melanoma with BRAF and MEK inhibitors

Selective inhibition of the mitogen activated protein kinase (MAPK) pathway with either BRAF or MEK inhibition has emerged as the key component for the treatment of BRAF-mutant metastatic melanoma. New evidence from several phase III trials suggests that the combination of BRAF and MEK inhibitors improves tumor response rate and progression-free survival (PFS). Some of the serious adverse events, in particular, the incidence of cutaneous squamous cell carcinoma seen with the monotherapy treatment with a BRAF inhibitor are attenuated with combination therapy, whereas milder side effects such as pyrexia can be more common with combination therapy. Although dose reductions and dose interruptions are slightly more common with combination therapy, overall data supports the notion that combination therapy is safe and improves the outcomes for metastatic melanoma patients compared to single agent BRAF inhibitors.

The Dissociation of Gefitinib Trough Concentration and Clinical Outcome in NSCLC Patients with EGFR Sensitive Mutations

Gefitinib is an essential drug for NSCLC patients harboring EGFR sensitive mutations. The approved dose 250 mg/day is based on limited clinical trials, this research aims to explore the relationship between drug exposure and gefitinib response. C trough of 87 NSCLC patients harboring EGFR sensitive mutations were determined by LC-MS/MS. The median of C trough was 173.9 ng/ml (P25-P75, 130.5-231.2 ng/ml), and cutoff value 200 ng/ml was determined by X-Tile. The PFS between C trough < 200 ng/ml and C trough ≥ 200 ng/ml groups were not significantly different (17.3 VS 14.8 months; p = 0.258). C trough was not significantly associated with rash, diarrhea and hepatotoxicity. Non-smokers enjoyed longer PFS than smokers (18.7 VS 9.3 months; p = 0.025). The results showed that, for NSCLC patients with EGFR sensitive mutations, the PFS in lower trough concentration group were not inferior to that in higher trough concentration group and dose reduction is a rational suggestion for adjustment of dose regimen for aforementioned patients. More clinical trials are warranted to explore the precision dose schedule of gefitinib.

Non-rash dermatologic adverse events related to targeted therapies

OBJECTIVES

To provide background information and management strategies for non-rash dermatological adverse events.

DATA SOURCES

Peer-reviewed journal articles, professional manuals, online sources.

CONCLUSION

During the last decade, many dermatological adverse events of targeted therapy have been reported, including xerosis, skin fissures, pruritus, photosensitivity, pigmentation changes, hair and nail changes, hand-foot skin reaction, squamoproliferative lesions, Stevens-Johnsons syndrome, and toxic epidermal necrolysis. Although evidenced-based treatment options are scarce, many recommendations have been described in the literature that should be considered to apply in daily practice.

IMPLICATIONS FOR NURSING PRACTICE

Nursing practice will be enhanced by education, assessment, and management recommendations.

New therapeutic options for advanced non-resectable malignant melanoma

Melanoma is a malignant tumor which is inclined to metastasize promptly into the lymphatic system and other organs such as lung, liver, brain or bone. Therefore early diagnosis remains crucial for improving clinical outcome for melanoma patients. Current chemotherapy and chemo-immunotherapy regimes have shown little clinical benefit with no improvement in overall survival. However, new advances in melanoma biology such as the discovery of predisposed gene signatures and key somatic events have changed clinical practice. New therapeutic approaches are being tested or have been approved by the FDA/EMA recently including targeted therapies, such as BRAF- and MEK-inhibitors, and novel immunotherapies, such as anti-CTLA4 or anti-PD1 therapies. For these therapies an improvement of progression-free and overall survival has been seen in patients with advanced non-resectable melanoma. The following review summarizes recent therapeutic options after the ASCO and ESMO annual meetings 2014 for the treatment of malignant melanoma.

Vemurafenib skin phototoxicity is indirectly linked to ultraviolet A minimal erythema dose decrease

BACKGROUND

Vemurafenib, an anti-rapidly accelerated fibrosarcoma kinase B (BRAF) molecule, improves survival among patients with metastatic BRAF-mutated melanoma. Photosensitivity, a frequent cutaneous adverse effect induced by vemurafenib, can lead to cessation of treatment.

OBJECTIVES

To investigate photosensitivity mechanisms in patients treated with vemurafenib for metastatic melanoma.

METHODS

In a prospective study of 12 patients, photobiological explorations with measurements of ultraviolet A (UVA) minimal erythema dose (MED) and polychromatic MED were performed over 3 days in all 12 patients. UVA MED and polychromatic MED were also assessed for four patients before treatment. We then performed spectrophotometric analyses of (i) serum and faeces in these four patients, before and after introduction of vemurafenib; (ii) the lyophilized form of vemurafenib without excipient added; and (iii) the lyophilized form of vemurafenib added to serum and faeces before treatment.

RESULTS

Photosensitivity was present in 92% of the patients. UVA MED was normal before treatment and decreased after treatment, while polychromatic MED remained normal. The same three peaks (210, 260 and 310 nm) were identified in the spectrum for UVB and UVC but not for UVA on spectrophotometric analyses for each condition (lyophilized vemurafenib; serum and faeces after introduction of vemurafenib; and lyophilized vemurafenib added to serum and faeces before treatment). The peaks were different before treatment.

CONCLUSIONS

Our study confirms that photosensitivity under vemurafenib treatment was a UVA phototoxicity reaction, and our results suggest that a metabolite of vemurafenib rather than the parent molecule is involved in this phototoxicity.

Comparative profile of cutaneous adverse events: BRAF/MEK inhibitor combination therapy versus BRAF monotherapy in melanoma

BACKGROUND

BRAF inhibitor (BRAFi) and MEK inhibitor (MEKi) frequently cause cutaneous adverse events.

OBJECTIVE

We sought to investigate the cutaneous safety profile of BRAFi versus BRAFi and MEKi combination regimens.

METHODS

We performed a retrospective cohort study, collecting data from 44 patients with melanoma treated either with BRAFi (vemurafenib or dabrafenib) or BRAFi and MEKi combination regimens (vemurafenib + cobimetinib or dabrafenib + trametinib). Patient characteristics, and the occurrence and severity of cutaneous adverse events, are described.

RESULTS

The development of cutaneous adverse events was significantly less frequent (P = .012) and occurred after longer treatment time (P = .025) in patients treated with BRAFi and MEKi combination regimen compared with patients treated with BRAFi monotherapy. Among patients who received both BRAFi and the combination of BRAFi and MEKi at different time points during their treatment course, the development of squamous cell carcinoma or keratoacanthoma was significantly less frequent when they received the combination regimen (P = .008). Patients receiving vemurafenib developed more cutaneous adverse events (P = .001) and in particular more photosensitivity (P = .010) than patients who did not.

LIMITATIONS

There were a limited number of patients.

CONCLUSION

Combination regimen with BRAFi and MEKi shows fewer cutaneous adverse events and longer cutaneous adverse event-free interval compared with BRAFi monotherapy.

Dermatological toxicity associated with targeted therapies in cancer: optimal management

Targeted therapies have developed rapidly over the last few years in the field of oncology thanks to a better understanding of carcinogenesis. They target pathways involved in signal transduction (EGFR, HER2, HER3, HER4, FLT3, RAS, RAF, MEK, KIT, RET, mTOR, SRC, EPH, SCF), tumor angiogenesis (VEGFR, TIE2), and tumor microenvironment (PDGFR, FGFR). They rarely cause the systemic adverse reactions generally associated with chemotherapy, but frequently cause disabling and specific skin toxicity. The impact on patient quality of life can be important both in terms of symptoms caused and of potentially aesthetic consequences. Inappropriate management can increase the risk of dose reduction or discontinuation of the cancer treatment. In this review, we will discuss skin toxicity associated with the main drug classes-EGFR, BRAF, MEK, mTOR, c-KIT, CTLA4, and SMO inhibitors, and anti-angiogenic agents. Targeted therapy-induced skin toxicities will be detailed in terms of symptoms, frequency, evolution, complications, and topical and oral treatments in order to improve their diagnosis and management.

Acneiform eruptions

Is it acne or is it not? When this question arises, we can presume that we have crossed the boundaries of "acneiform eruptions" of the face. Although acne may be considered a condition fairly easy to diagnose, it is not rare for the practicing dermatologist or the general physician to wonder when faced with an acneiform eruption before establishing a diagnosis. In this review, we address facial acneiform eruptions in children and in adults, including perioral dermatitis, granulomatous periorificial dermatitis, nevus comedonicus, acne cosmetica, rosacea, demodicosis, folliculitis, acneiform presentation of cutaneous lymphomas, and drug-induced [epidermal growth factor receptor (EGFR) inhibitors, steroids, etc.] acneiform eruptions, along with their diagnosis and therapeutic approaches. The major distinguishing factor in acneiform eruptions is that, in contrast to acne, there are no comedones (whiteheads or blackheads).

Epidermal growth factor receptor signalling in keratinocyte biology: implications for skin toxicity of tyrosine kinase inhibitors

The epidermal growth factor receptor (EGFR) and its ligands have been long recognized as centrally involved in the growth and repair process of epithelia, as well as in carcinogenesis. In addition, the EGFR has been demonstrated to be importantly involved in the control of inflammatory responses. During this last decade, a number of highly specific agents targeting this system have become an integral component of pharmacologic strategies against many solid malignancies. These drugs have led to increased patient survival and made therapy more tolerant when compared to conventional cytotoxic drugs. Nonetheless, their use is associated with a constellation of toxic effects on the skin, including follicular pustules, persistent inflammation, xerosis and pruritus, and enhanced susceptibility to infections. This dramatic impairment of skin homoeostasis underscores the centrality of the EGFR-ligand system in the whole skin immune system. So far, no mechanism-based approaches are available to specifically counteract the adverse effects of anti-EGFR drugs or any other class of tyrosine kinase inhibitors. Only the knowledge of the cellular and molecular events underlying these adverse effects in humans, combined with in vitro/in vivo models able to mimic these toxic responses, may guide the development of mechanism-based treatment or prevention strategies.

The use of vemurafenib in Australian patients with unresectable or metastatic melanoma containing the V600 BRAF gene mutation

Metastatic melanoma remains one of the major causes of death related to skin cancers and has been resistant to traditional anticancer therapies. The clinical development of vemurafenib in the treatment of metastatic melanoma with the V600 mutation of the BRAF gene has provided meaningful improvements in the overall survival and progression-free survival of metastatic melanoma patients. However, significant side effects have been noted with this therapy, in particular cutaneous adverse events (AEs) such as rashes, squamous cell carcinoma and severe photosensitivity to UVA light among others. With an emphasis on the Australian perspective, this review provides an overview of the clinical development of vemurafenib, its attendant dose-limiting toxicities and other AEs, recommendations for safety monitoring, supportive treatments of AEs and dose modifications, with the aim of maximizing the chances of continuing beneficial treatment.

Cutaneous adverse effects of BRAF inhibitors in metastatic malignant melanoma, a prospective study in 20 patients

BACKGROUND

BRAF inhibitors frequently cause significant cutaneous adverse reactions.

OBJECTIVE

To study the timing, prevalence and response to treatment of skin lesions in patients receiving V-raf murine sarcoma viral oncogene homolog B1 (BRAF) inhibitors.

METHODS

We prospectively studied the cutaneous side-effects of patients with a BRAF mutant (V600E, V600K, V600R) metastatic malignant melanoma treated with a BRAF inhibitor. We systematically registered prevalence, timing of onset and response to treatment.

RESULTS

Twenty patients were treated for 2-52 weeks with a BRAF inhibitor. Eleven patients on vemurafenib (58%) developed cutaneous side-effects and 10 patients (42%) had more than one cutaneous adverse event. Verrucous papillomas were observed in eight patients (42%), after 1-12 weeks. We diagnosed four keratoacanthomas in two patients (11%) after 6-10 weeks and two squamous cell carcinomas in two patients (11%) after 10-16 weeks. Seven patients (37%) developed a hyperkeratotic, folliculocentric eruption after 2-8 weeks, resolving quickly under topical steroids. Four patients (21%) presented a facial erythema, two patients (11%) a seborrhoeic dermatitis-like eczema on the scalp. Three patients (16%) developed cystic lesions after 2-11 weeks. Three patients (16%) presented a hand-foot skin reaction after 4-6 weeks, which was successfully treated with topical steroids and keratolytics. Hyperkeratosis of the nipples was seen in one patient (5%). We observed phototoxic reactions after UV exposure in five patients (26%) and alopecia in two patients (11%) after 8-10 weeks. One patient on dabrafenib developed curly hairs (24 weeks), keratotic papules (1 and 36 weeks), a keratoacanthoma (4 weeks) and a hand-foot skin reaction (31 weeks).

CONCLUSION

Multiple cutaneous toxicities were observed in patients under BRAF inhibitors, mostly well controlled with adequate treatment. We recommend a multidisciplinary approach with regular assessments of the skin by a dermatologist. This allows early identification and adequate treatment to avoid premature discontinuation of a life-prolonging therapy.

Combining machine learning systems and multiple docking simulation packages to improve docking prediction reliability for network pharmacology

Increased availability of bioinformatics resources is creating opportunities for the application of network pharmacology to predict drug effects and toxicity resulting from multi-target interactions. Here we present a high-precision computational prediction approach that combines two elaborately built machine learning systems and multiple molecular docking tools to assess binding potentials of a test compound against proteins involved in a complex molecular network. One of the two machine learning systems is a re-scoring function to evaluate binding modes generated by docking tools. The second is a binding mode selection function to identify the most predictive binding mode. Results from a series of benchmark validations and a case study show that this approach surpasses the prediction reliability of other techniques and that it also identifies either primary or off-targets of kinase inhibitors. Integrating this approach with molecular network maps makes it possible to address drug safety issues by comprehensively investigating network-dependent effects of a drug or drug candidate.

Exploratory toxicology as an integrated part of drug discovery. Part I: Why and how

Toxicity and clinical safety have major impact on drug development success. Moving toxicological studies into earlier phases of the R&D chain prevents drug candidates with a safety risk from entering clinical development. However, to identify candidates without such risk, safety has to be designed actively. Therefore, we argue that toxicology should be fully integrated into the discovery process. We describe our strategy, including safety assessment of novel targets, selection of chemical series without inherent liabilities, designing out risk factors and profiling of candidates, and we discuss considerations regarding what to screen for. We aim to provide timely go/no-go decisions (fail early) and direction to the discovery teams, by steering away from safety risk (showing what will not fail).

Assessment of Augmented Immune Surveillance and Tumor Cell Death by Cytoplasmic Stabilization of p53 as a Chemopreventive Strategy of 3 Promising Medicinal Herbs in Murine 2-Stage Skin Carcinogenesis

Cancer is the final outcome of a plethora of events. Targeting the proliferation or inducing programmed cell death in a proliferating population is a major standpoint in the cancer therapy. However, proliferation is regulated by several cellular and immunologic processes. This study reports the inhibition of proliferation by augmenting immune surveillance, silencing acute inflammation, and inducing p53-mediated apoptosis of skin cancer by 3 promising medicinal extracts. We used the well-characterized model for experimental skin carcinogenesis in mice for 32 weeks to study the chemopreventive effect of the methanolic extracts of Trigonella foenumgraecum, Eclipta alba, and Calendula officinalis. All 3 extracts reduced the number, incidence, and multiplicity of tumors, which was confirmed by the pathologic studies that showed regressed tumors. There was a significant reduction in the PCNA+ nuclei in all treatment groups 32 weeks after the initiation. Mechanistic studies revealed that proliferative population in tumors is diminished by the restoration of the endogenous antioxidant defense, inhibition of the stress-related signal-transducing element NFκB, reduction of inflammation, enhancement of immunosurveillance of the genetically mutated cells, along with silencing of the cell cycle progression signals. Finally, all 3 medicinal extracts induced stable expression of p53 within the tumors, confirmed by the CFDA-Cy3 apoptosis assay. Results of our study confirm that these extracts not only limit the rate of proliferation by inhibition of the processes integral to cancer development but also induce stable cytoplasmic expression of p53-mediated apoptosis, leading to fewer and regressed tumors in mice.

Dabrafenib therapy for advanced melanoma

OBJECTIVE

To summarize the clinical development of dabrafenib and to highlight the clinically relevant distinct characteristics of dabrafenib in contrast to vemurafenib.

DATA SOURCE

An English-language literature search of MEDLINE/PubMed (1966-June 2013), using the keywords GSK2118436, dabrafenib, vemurafenib, selective BRAF inhibitor, and advanced melanoma, was conducted. Data were also obtained from package inserts, meeting abstracts, and clinical registries.

STUDY SELECTION AND DATA EXTRACTION

All relevant published articles on dabrafenib and vemurafenib were reviewed. Clinical trial registries and meeting abstracts were used for information about ongoing studies.

DATA SYNTHESIS

BRAF(V600E) mutation confers constitutive BRAK kinase activation in melanoma cells, promoting tumor growth. This discovery led to the development of BRAF kinase inhibitors like vemurafenib and dabrafenib. Dabrafenib has been approved to treat patients with BRAF(V600E)-positive unresectable or metastatic melanoma based on its clinical benefit demonstrated in a randomized phase III study. It has also been shown to be safe and effective in patients with BRAF mutant advanced melanoma involving the brain. Dabrafenib is well tolerated, with the most common adverse effects being hyperkeratosis, headache, pyrexia, and arthralgia. Currently, there is no evidence to suggest that one BRAF inhibitor is superior to the other. With similar efficacy, therapy selection will likely be influenced by differential tolerability and cost.

CONCLUSIONS

Dabrafenib joins vemurafenib to confirm the superior clinical outcome of the BRAF inhibitors when compared with dacarbazine in patients with BRAF(V600E)-positive advanced melanoma. Active research is ongoing to expand its utility into the adjuvant setting and to circumvent rapid emergence of drug resistance.