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

Grover's-like drug eruption in a patient with metastatic melanoma under ipilimumab therapy

Background

Dermatologic toxicity is an important adverse effect of immune checkpoint inhibitors targeting cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) and programmed cell death 1 receptor (PD-1) or PD ligand 1 (PD-L1). Skin toxicity most commonly includes a maculopapular erythematous rash and pruritus. Rarely life threatening complications such as Steven’s Johnson syndrome or toxic epidermal necrolysis may occur.

Case presentation

Here we report the uncommon event of a drug-induced transient acantholytic dermatosis (Grover’s disease) in a 73-year-old Caucasian male treated with ipilimumab for metastatic melanoma. Five weeks after initiation of therapy, the patient developed a widespread polymorphic papulovesicular dermatosis on the trunk and proximal extremities with intense pruritus. Skin biopsy showed acantholytic dyskeratosis with interface dermatitis consistent with a Grover’s-like drug eruption.

Conclusions

These findings should raise awareness for uncommon immune-related dermatological toxicities of immunomodulatory antibodies targeting the CTLA-4 signaling axis. We recommend biopsies of unexpected skin lesions to rapidly identify dermatological adverse events of immune checkpoint inhibitors.

Combined Therapy with Dabrafenib and Trametinib in BRAF-Mutated Metastatic Melanoma in a Real-Life Setting: The INT Milan Experience

Purpose

Combination therapy with dabrafenib and trametinib is safer and more effective than BRAF inhibitor-based monotherapy for metastatic melanoma.

Methods

We retrospectively analyzed BRAF-mutated metastatic melanoma patients treated at our institution with daily oral dabrafenib 300 mg and trametinib 2 mg from November 2013 to April 2016. This clinical record included both untreated and previously treated stage IV melanomas. Physical examination and laboratory examinations were performed monthly and disease re-evaluations were performed every 3 months.

Results

A total of 48 patients (24 male, 24 female) with BRAF-mutated metastatic melanoma received dabrafenib and trametinib; median age was 48 years (range 23-75). Median follow-up was 362.5 days (range 72-879). Best overall response rate consisted of 6.2% (3 patients) complete response, 64.6% (31) partial response, and 25% ( 12 ) stable disease; median time to best response was 11 weeks (range 5.7-125.5). Progression of disease was seen in 19 patients (39.6%), with median time to progression (TTP) of 26 weeks (range 8-54). A total of 15 patients (31.2%) died due to progression of disease. Median progression-free survival and median overall survival were not reached. To date, 30 patients (62.5%) are still under treatment. A total of 27 (56.2%) patients had at least one adverse event (AE); grade 3-4 AEs were seen in 4 cases (8.3%). The main toxicities were fever (25%), skin rash (14.6%), arthralgias (10.4%), and aspartate aminotransferase/alanine aminotransferase increase (8.3%). Treatment dose was reduced in 7 subjects (14.6%), with only one case of discontinuation due to AE.

Conclusions

Our data, using combined targeted therapy, are in line with the scientific literature in terms of both safety and effectiveness in a real-life setting.

Managing Cutaneous Side Effects From Targeted Molecular Inhibitors for Melanoma and Nonmelanoma Skin Cancer

BACKGROUND

Targeted anticancer therapies can cause cutaneous adverse events different from classical chemotherapeutic toxicities.

OBJECTIVE

To review the literature on dermatologic adverse events (DAEs) of targeted molecular inhibitors for melanoma and nonmelanoma skin cancers with a focus on management options.

MATERIALS AND METHODS

A comprehensive literature search related to the side effects and management of these side effects from vemurafenib, dabrafenib, trametinib (BRAF inhibitors), pembrolizumab (antiprogrammed-death-receptor-1 antibody), imatinib (tyrosine kinase inhibitor), ipilimumab (anticytotoxic T-lymphocyte antigen-4 antibody), cetuximab (epidermal growth factor receptor inhibitor), sorafenib (multikinase inhibitor), and vismodegib (smoothened receptor inhibitor).

RESULTS

No large controlled studies specifically examining the management of DAEs of targeted molecular inhibitors exist, although there are case report-based recommendations and algorithms developed by expert panels to manage these adverse events.

CONCLUSION

Many options for managing the cutaneous side effects of targeted molecular inhibitors are similar to those used in general dermatology practice. When used effectively, drug dosing and patient quality of life may be optimized.

The occurrence of non-melanoma malignant skin lesions and non-cutaneous squamous-cell carcinoma among metastatic melanoma patients: an observational cohort study in Denmark

BACKGROUND

Inhibitors of mutant BRAF are emerging as standard of care in patients with metastatic melanoma who carry relevant oncogenic mutations. However, BRAF inhibitors are found to induce cutaneous squamous cell carcinoma (cuSCC). Population-based background rates of cuSCC and non-cutaneous squamous cell carcinoma (non-cuSCC) in the metastatic melanoma population may contextualize safety signals from randomized clinical trials or the clinics. However, these background rates are lacking.

METHODS

We conducted a historical cohort study to evaluate the background rates of new-onset non-melanoma skin lesions and non-cuSCC among 2,814 metastatic malignant melanoma patients diagnosed in 1997-2010, identified through the Danish Cancer Registry and the National Pathology Registry. Patients were excluded if they had a history of cancer before the metastatic melanoma diagnosis, other than skin cancers. We determined the incidence of non-melanoma malignant skin lesions and non-cuSCC that occurred post metastatic melanoma diagnosis, censoring patients at death, emigration, or December 31, 2011 (end of study period), whichever came first.

RESULTS

The median age at metastatic melanoma diagnosis was 64 years. Over 40% of patients died within one year of metastatic diagnosis and ~70% died within 5 years. The percentages of patients with prior history or prevalent disease at metastatic melanoma diagnosis included: 8.6% with cuSCC or basal cell carcinoma (BCC), 3.9% with actinic keratosis (AK), and 0.7% with Bowen's disease. No patients had past or current non-cuSCC per study exclusion criterion. The incidence of non-melanoma skin lesions during the 6 months post-metastatic melanoma diagnosis was as follows: BCC, 1.8% (42.5 per 1000 person-years [PY]); AK, 0.8% (18.6 per 1000 PY); cuSCC, 0.1% (1.7 per 1000 PY); Bowen's disease, 0.04% (0.8 per 1000 PY); and keratoacanthoma (KA), 0%. Non-cuSCC was observed in 3 patients (0.1%; 2.5 per 1000 PY) at 3 sites: bronchi, heart and lung.

CONCLUSION

CuSCC and non-cuSCC were rare events among metastatic melanoma patients.

Late-onset robust curly hair growth in a patient with BRAF-mutated metastatic melanoma responding to dabrafenib

Development of curly hair has been infrequently described in association with BRAF inhibitors in clinical trials, and usually affects patients between 6 and 24 weeks of therapy. The curly hair is typically preceded by initial hair thinning or even diffuse alopecia. We report herein an occurrence of late-onset robust curly head hair growth in a patient with metastatic melanoma responding well to dabrafenib, without being preceded by hair thinning. The curly hair in our patient developed at 11 months of therapy with dabrafenib. Occurrence of late-onset, robust curly hair might represent a prognostic marker of clinical response to these agents. If our hypothesis is correct, we expect more reports of late-onset, robust curly hair growth with the use of this class of pharmaceuticals. Moreover, newer generations of BRAF inhibitors may expand the armory of hair care products in the future.

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.

Keratoacanthoma (KA): An update and review

Keratoacanthoma (KA) is a common but underreported tumor of the skin. Two striking features of KA are its clinical behavior with spontaneous regression after rapid growth and its nosological position on the border between benignity and malignancy. We review current knowledge on the clinical, histopathological, and dermoscopic features of KA to ensure a proper diagnosis and describe its variants, including different types of multiple KAs. We highlight current concepts of KA ethiopathogenesis with special emphasis on the genetic background of multiple familial KA, the role of Wnt signaling pathway, and induction of KA by BRAF inhibitors and procedures of esthetic dermatology. Finally, treatment strategies are presented with surgical excision as a first option, followed by other modalities, including intralesional chemotherapy, topical and systemic agents, lasers, cryotherapy, and photodynamic therapy.

Cutaneous adverse events (AEs) of anti-programmed cell death (PD)-1 therapy in patients with metastatic melanoma: A single-institution cohort

BACKGROUND

Anti-programmed cell death (PD)-1 therapy is emerging as the backbone of new standard of care immunotherapy for metastatic melanoma. Immune-related cutaneous events are observed in these patients.

OBJECTIVE

We sought to describe cutaneous adverse events observed in patients with metastatic melanoma on anti-PD-1 therapy.

METHODS

We reviewed the clinical and histologic information of all patients treated with single-agent anti-PD-1 therapy for metastatic melanoma at Westmead Hospital, Sydney, Australia, from May 2012 to February 2015.

RESULTS

Of the 82 patients included in the study, 34 had dermatology assessments. Forty (49%) developed a form of anti-PD-1-associated cutaneous adverse events. In all, 17% developed lichenoid reactions and eczema, and 15% developed vitiligo. An estimated 25% of patients were expected to develop their first lichenoid reactions within 8.3 months, and eczema and vitiligo within 10.3 months of therapy. These adverse events tend to appear together in patients on anti-PD-1 therapy.

LIMITATIONS

The study was from a single center and clinical information was reviewed retrospectively in patients not referred to dermatology.

CONCLUSION

Anti-PD-1 therapy is associated with the development of immune-related cutaneous events. Lichenoid reactions, eczema, and vitiligo are the 3 most prevalent lesions observed in our population. There is a tendency for lichenoid reactions and eczema to occur with vitiligo.

Mutational Analysis of BRAF Inhibitor-Associated Squamoproliferative Lesions

In recent years, there has been increasing use of BRAF-inhibiting drugs for the treatment of various malignancies, including melanoma. However, these agents are associated with the development of other nonmelanoma skin lesions, in particular squamoproliferative lesions such as keratoacanthomas (KAs), squamous cell carcinomas, and BRAF inhibitor-associated verrucous keratoses. The molecular pathogenesis of these lesions is of interest, not only for therapeutic reasons, but also for the insight it might provide into the development of similar lesions in a sporadic setting. We used next-generation sequencing to compare the mutational profiles of lesions after treatment with a BRAF inhibitor, with similar lesions arising sporadically. HRAS mutations were common among the BRAF inhibitor-induced lesions, being identified in 56%, compared with 14% of lesions in the sporadic group (P = 0.002). Thus, despite similar histomorphological appearances, the underlying molecular mechanisms may be different. In addition, within the BRAF inhibitor-associated group, the lesions designated as KAs and BRAF inhibitor-associated verrucous keratoses had a similar mutational profile (mutations in PIK3CA, APC, and HRAS), which was distinct to that seen in squamous cell carcinomas (FGFR3, CDKN2A, and STK11). We have previously noted histological overlap between KAs and BRAF inhibitor-associated verrucous keratoses, and this finding supports the notion that they may represent morphological or temporal variants of a single lesion type.

Dabrafenib and its use in the treatment of metastatic melanoma

Approximately 50% of melanomas have mutations in the gene encoding BRAF. In recent years, new targeted therapies have transformed the landscape of metastatic melanoma treatment. Dabrafenib, a potent kinase inhibitor of mutated BRAF, has been showed to have high response rates with a rapid onset of response, as well as improved overall and progression-free survival when compared with chemotherapy. Dabrafenib in combination with trametinib, a MEK inhibitor, has demonstrated higher responses and improved clinical efficacy compared with monotherapy. Toxicity is distinct compared with chemotherapy but manageable. This article summarizes the pharmacology, key clinical trial data as well as practical experience with dabrafenib in clinical practice, and future directions.

BGB-283, a Novel RAF Kinase and EGFR Inhibitor, Displays Potent Antitumor Activity in BRAF-Mutated Colorectal Cancers

Oncogenic BRAF, which drives cell transformation and proliferation, has been detected in approximately 50% of human malignant melanomas and 5% to 15% of colorectal cancers. Despite the remarkable clinical activities achieved by vemurafenib and dabrafenib in treating BRAF(V600E) metastatic melanoma, their clinical efficacy in BRAF(V600E) colorectal cancer is far less impressive. Prior studies suggested that feedback activation of EGFR and MAPK signaling upon BRAF inhibition might contribute to the relative unresponsiveness of colorectal cancer to the first-generation BRAF inhibitors. Here, we report characterization of a dual RAF kinase/EGFR inhibitor, BGB-283, which is currently under clinical investigation. In vitro, BGB-283 potently inhibits BRAF(V600E)-activated ERK phosphorylation and cell proliferation. It demonstrates selective cytotoxicity and preferentially inhibits proliferation of cancer cells harboring BRAF(V600E) and EGFR mutation/amplification. In BRAF(V600E) colorectal cancer cell lines, BGB-283 effectively inhibits the reactivation of EGFR and EGFR-mediated cell proliferation. In vivo, BGB-283 treatment leads to dose-dependent tumor growth inhibition accompanied by partial and complete tumor regressions in both cell line-derived and primary human colorectal tumor xenografts bearing BRAF(V600E) mutation. These findings support BGB-283 as a potent antitumor drug candidate with clinical potential for treating colorectal cancer harboring BRAF(V600E) mutation.

YY1 regulates melanoma tumorigenesis through a miR-9 ~ RYBP axis

Background

The Yin Yang 1 (YY1) transcription factor has been identified to target a plethora of potential target genes, which are important for cell proliferation and differentiation. Although the role that YY1 plays in different human types of cancer has been reported, its biological and mechanistic significance in melanoma has not been well defined.

Methods

Quantitative RT-PCR analysis was used to determine whether aberrant YY1 and miR-9 expression occurred in melanoma, compared with benign nevi and normal tissue controls. Furthermore, the transcriptional regulation of YY1 on miR-9 expression was assessed by using quantitative ChIP-PCR assay. Subsequently, the effects of YY1 and miR-9 on proliferation, cell cycle, migration and invasion of melanoma cells were detected using CCK-8, flow cytometric analysis, wound healing and transwell invasion assays, respectively. Finally, the post-transcriptional regulation of miR-9 on RYBP was analyzed using luciferase reporter and immunoblot analysis.

Results

Elevated YY1 levels were observed in patients with melanoma, compared with benign nevi and normal tissue controls, and the increased YY1 was associated with melanoma metastasis state and tumor stage. Furthermore, YY1 negatively regulated miR-9 transcription. Silencing of YY1 inhibited proliferation, cell cycle progression, migration and invasion in melanoma cells, while ectopic of miR-9 did the same. Additionally, RYBP was shown to be a direct target of miR-9 through binding to its 3′ UTR, thus forming a YY1 ~ miR-9 ~ RYBP axis.

Conclusions

These results identify a novel YY1 ~ miR-9 ~ RYBP axis involved in melanoma tumorigenesis and reinforce the idea that regulatory circuitries involving miRNAs and TFs are prevalent mechanisms.

Contribution of Beta-HPV Infection and UV Damage to Rapid-Onset Cutaneous Squamous Cell Carcinoma during BRAF-Inhibition Therapy

PURPOSE

BRAF-inhibition (BRAFi) therapy for advanced melanoma carries a high rate of secondary cutaneous squamous cell carcinoma (cSCC) and risk of other cancers. UV radiation and α-genus human papillomavirus (HPV) are highly associated with SCC, but a novel role for β-genus HPV is suspected in BRAFi-cSCC. Cutaneous β-HPV may act in concert with host and environmental factors in BRAFi-cSCC.

EXPERIMENTAL DESIGN

Primary BRAFi-cSCC tissue DNA isolated from patients receiving vemurafenib or dabrafenib from two cancer centers was analyzed for the presence of cutaneous oncogenic viruses and host genetic mutations. Diagnostic specimens underwent consensus dermatopathology review. Clinical parameters for UV exposure and disease course were statistically analyzed in conjunction with histopathology.

RESULTS

Twenty-nine patients contributed 69 BRAFi-cSCC lesions. BRAFi-cSCC had wart-like features (BRAFi-cSCC-WF) in 22% of specimens. During vemurafenib therapy, BRAFi-cSCC-WF arose 11.6 weeks more rapidly than conventional cSCC when controlled for gender and UV exposure (P value = 0.03). Among all BRAFi-cSCC, β-genus HPV-17, HPV-38, HPV-111 were most frequently isolated, and novel β-HPV genotypes were discovered (CTR, CRT-11, CRT-22). Sequencing revealed 63% of evaluated BRAFi-cSCCs harbored RAS mutations with PIK3CA, CKIT, ALK, and EGFR mutations also detected.

CONCLUSIONS

We examined clinical, histopathologic, viral, and genetic parameters in BRAFi-cSCC demonstrating rapid onset; wart-like histomorphology; β-HPV-17, HPV-38, and HPV-111 infection; UV damage; and novel ALK and CKIT mutations. Discovered β-HPV genotypes expand the spectrum of tumor-associated viruses. These findings enhance our understanding of factors cooperating with BRAF inhibition that accelerate keratinocyte oncogenesis as well as broaden the knowledge base of multifactorial mediators of cancer in general.

Acneiform eruption in a patient with metastatic melanoma after ceasing combination dabrafenib/trametinib therapy

BRAF inhibitors (BRAFi) and MEK inhibitors (MEKi) increase survival in BRAF mutant metastatic melanoma patients; however, they induce a well-known spectrum of cutaneous side effects during treatment. Whereas the BRAFi dabrafenib induces cutaneous squamous cell carcinomas and verrucal keratosis, the MEKi trametinib frequently induces acneiform eruptions that are reversible after drug discontinuation. Furthermore, when dabrafenib and trametinib are used in combination, there are fewer cutaneous toxicities. We report a patient with BRAF mutant metastatic melanoma treated with the BRAFi/MEKi combination therapy who developed an acneiform eruption after treatment discontinuation rather than during active therapy. Moreover, the eruption resolved when the combination treatment was reintroduced and recurred after increasing the dose of trametinib. The eruption may be explained by the longer half-life of trametinib (4.5 days) compared with dabrafenib (5.2 h). This is the first case reported with this particular side effect induced after stopping the treatment and could become more frequent as the BRAFi/MEKi combination of drugs is more frequently prescribed.

[Cutaneous side effects of anti-tumor therapy with BRAF and MEK inhibitors]

BACKGROUND

BRAF and MEK inhibitors are new targeted therapies which are used in the treatment of malignancies, in particular of malignant melanoma.

SIDE EFFECTS

Cutaneous side effects are common during the treatment with both types of inhibitors. These side effects include inflammatory reactions such as maculopapular and papulopustular exanthema, hand-foot syndrome, panniculitis, paronychia, photo- and radio-sensitization. As a class effect, BRAF-inhibitors induce proliferative disorders of keratinocytes and melanocytes, such as palmoplantar hyperkeratosis (as part of the hand-foot syndrome), verruciform and acanthoma-like lesions, follicular and Grover disease-like hyperkeratoses, keratoacanthomas, squamous cell carcinomas and atypical melanocytic nevi with transition to secondary melanomas. Furthermore, hair alterations and xerosis are possible.

CONCLUSIONS

Treatment with BRAF and MEK inhibitors requires close dermatologic monitoring of the patient. This manuscript summarizes the most frequent cutaneous side effects and their management.

Cutaneous adverse effects of targeted therapies: Part II: Inhibitors of intracellular molecular signaling pathways

The last decade has spawned an exciting new era of oncotherapy in dermatology, including the development of targeted therapies for metastatic melanoma and basal cell carcinoma. Along with skin cancer, deregulation of the PI3K-AKT-mTOR and RAS-RAF-MEK-ERK intracellular signaling pathways contributes to tumorigenesis of a multitude of other cancers, and inhibitors of these pathways are being actively studied. Similar to other classes of targeted therapies, cutaneous adverse effects are among the most frequent toxicities observed with mitogen-activated protein kinase pathway inhibitors, PI3K-AKT-mTOR inhibitors, hedgehog signaling pathway inhibitors, and immunotherapies. Given the rapid expansion of these families of targeted treatments, dermatologists will be essential in offering dermatologic supportive care measures to cancer patients being treated with these agents. Part II of this continuing medical education article reviews skin-related adverse sequelae, including the frequency of occurrence and the implications associated with on- and off-target cutaneous toxicities of inhibitors of the RAS-RAF-MEK-ERK pathway, PI3K-AKT-mTOR pathway, hedgehog signaling pathway, and immunotherapies.

Multiple milia formation induced by dovitinib

Dovitinib is a novel multi-target tyrosine kinase inhibitor that inhibits vascular endothelial growth factor receptor-1-3, platelet-derived growth factor receptor-β, Fms-like tyrosine kinase 3, c-Kit and fibroblast growth factor receptor-1-3. This compound is currently being assessed clinically for treatment of various malignancies. In phase I and II clinical trials of dovitinib treatment for renal cell carcinoma, 20% of patients experienced cutaneous adverse events, although the specific type of skin rash was not documented. Here, we report two cases of multiple milia formation induced by dovitinib. We believe our cases are the first report mainly showing non-inflammatory cystic structure.

Cutaneous keratoacanthomas/squamous cell carcinomas associated with neutralization of transforming growth factor β by the monoclonal antibody fresolimumab (GC1008)

Fresolimumab is an antibody capable of neutralizing all human isoforms of transforming growth factor beta (TGFβ) and has demonstrated anticancer activity in investigational studies. Inhibition of TGFβ by fresolimumab can potentially result in the development of cutaneous lesions. The aim of this study was to investigate the clinical, histological, and immunohistochemical characteristics of cutaneous neoplasms associated with fresolimumab. Skin biopsies (n = 24) were collected and analyzed from patients (n = 5) with treatment-emergent, cutaneous lesions arising during a phase 1 study of multiple doses of fresolimumab in patients (n = 29) with melanoma or renal cell carcinoma. Blinded, independent histological review and measurements of Ki-67, p53, and HPV integration were performed. Based on central review, four patients developed lesions with histological characteristics of keratoacanthomas, and of these patients, a single case of well-differentiated squamous cell carcinoma was also found. Expression of Ki-67, no evidence of p53 overexpression, and only focal positivity for human papillomavirus RNA by in situ hybridization in 4/18 cases were consistent with these findings. Following completion of fresolimumab, lesions spontaneously resolved. Therefore, benign, reversible keratoacanthomas were the most common cutaneous neoplasms observed, a finding of importance for adverse event monitoring, patient care, and optimization of therapies targeting TGFβ.

BRAF inhibitors: experience in thyroid cancer and general review of toxicity

The US Food and Drug Administration-approved BRAF inhibitors, vemurafenib and dabrafenib, have demonstrated superior efficacy in patients with BRAF-mutant melanomas but have limited efficacy in BRAF-mutant colorectal cancer. Little is known at this time regarding BRAF inhibitors in thyroid cancer. Initial reports in patients with progressive, radioactive iodine-refractory BRAF-mutant papillary thyroid cancer suggest response rates of approximately 30-40%. In this review, we discuss BRAF inhibitors in the context of thyroid cancer, the toxicities associated with BRAF inhibitors, and the suggested management of those toxicities. The management of vemurafenib and dabrafenib toxicities is applicable across all tumor types and may serve as a practical guide to their use.

[Acantholytic dermatosis in patients treated by vemurafenib: 2 cases]

BACKGROUND

Acantholytic dyskeratosis under BRAF inhibitors are dermatological diseases rarely reported to date.

PATIENTS AND METHODS

We report 2 cases of acantholytic dyskeratosis, reaching the trunk and the seborrheic zones, not itchy, appeared one month after the introduction of vemurafenib. The histological analysis was typical of a "Grover-like rash" for the 2 patients.

DISCUSSION

The appearance of acantholytic dyskeratosis under vemurafenib, a BRAF inhibitor, seems related with a paradoxical activation of the MAP-kinases pathway and with a growth acceleration of lesions in which RAS mutations of keratinocytes. Theses dermatoses seem also to occur with dabrafenib.

CONCLUSION

The patients treated by BRAF inhibitors (vemurafenib and dabrafenib) can present acantholytic dyskeratosis. The arisen of this mild dermatosis does not question, of course, the continuation of the treatment. These cutaneous manifestations can be managed with emollients.

Cutaneous adverse events in patients treated with BRAF inhibitor-based therapies for metastatic melanoma for longer than 52 weeks

BACKGROUND

BRAF inhibitor-based therapies have been shown to induce cutaneous toxicities, with onset generally in the first 8-26 weeks of therapy.

OBJECTIVES

To determine whether cutaneous toxicities persist in patients who have remained on BRAF inhibitor-based therapies for longer than 52 weeks, and therefore whether ongoing dermatology assessment is required.

METHODS

All patients treated with the BRAF inhibitors vemurafenib or dabrafenib or combination BRAF inhibitor and mitogen-activated protein kinase kinase (MEK) inhibitor therapy at Westmead Hospital, Sydney, Australia underwent regular dermatological assessments for the duration of therapy. All patients enrolled in a clinical trial, and 18% of patients in the compassionate access scheme underwent a baseline assessment prior to commencement of therapy and every 4-8 weeks thereafter. Patients' adverse events were recorded in a specific database.

RESULTS

Patients continued to develop cutaneous adverse events after 52 weeks of continuous therapy. Patients on single-agent BRAF inhibitor therapy suffered from Grover disease (45%), plantar hyperkeratosis (45%), verrucal keratosis (18%) and even cutaneous squamous cell carcinoma (16%). The most frequent adverse event seen in patients in the combination BRAF and MEK inhibitor group was an acneiform eruption (40%).

CONCLUSIONS

Patients on BRAF inhibitor-based therapies need to continue to have regular dermatological follow-up independent of the duration of their therapy.

Presence of human polyomavirus 6 in mutation-specific BRAF inhibitor-induced epithelial proliferations

IMPORTANCE

A frequent adverse effect of mutation-specific BRAF inhibitor therapy is the induction of epithelial proliferations including cutaneous squamous cell carcinomas. To date, the only factor identified contributing to their development is the activation of the mitogen-activated signal transduction cascade by mutations in the RAS genes. However, these mutations explain only 60% of the tumors; hence, it is important to identify what is causing the remaining tumors.

OBJECTIVE

To test for the presence of human papillomaviruses (HPVs) and the recently identified human polyomaviruses (HPyVs), Merkel cell polyomavirus (MCPyV), and trichodysplasia spinulosa-associated polyomavirus (TSPyV), as well as HPyV-6, HPyV-7, HPyV-9, and HPyV-10, in epithelial proliferations occurring after BRAF inhibitor therapy to determine whether these oncogenic viruses may contribute to BRAF inhibitor-induced skin tumors.

DESIGN, SETTING, AND PARTICIPANTS

Retrospective study at a university hospital in Austria of epithelial proliferations that developed in patients with melanoma after initiation of treatment with the BRAF inhibitor vemurafenib. Samples were analyzed for (1) presence of the most frequently observed RAS mutations by SNaPshot technology, (2) detection of the viruses by real-time polymerase chain reaction, and (3) presence of capsid proteins of the most abundantly detected virus by immunohistochemical analysis.

MAIN OUTCOMES AND MEASURES

RAS mutational status, as well as HPV and HPyV presence, in BRAF inhibitor-induced epithelial proliferations.

RESULTS

Eighteen biopsy samples from 6 patients were retrieved from our hospital's archive. We identified RAS mutations in 10 (62%) of the 16 samples with clear results. DNA of HPyV-9, HPyV-10, and TSPyV were virtually absent in the samples. MCPyV DNA was present in 13 of 18 samples, and HPV, HPyV-6, and HPyV-7 DNA were present in all samples. In general, the amount of DNA encoding the latter viruses was rather low, with the exception of HPyV-6 in several samples of 1 individual patient. Notably, the relevance of the presence of HPyV-6 in the epithelial proliferation was underlined by immunohistochemical detection of the core protein VP1 of HPyV-6.

CONCLUSIONS AND RELEVANCE

The presence of both high HPyV-6 DNA load and VP1 protein suggests that polyomaviruses may contribute to the epithelial proliferations observed in patients receiving BRAF inhibitor therapy, albeit the relative impact as compared with that of RAS mutations appears circumstantial.

Cutaneous epithelial tumors induced by vemurafenib involve the MAPK and Pi3KCA pathways but not HPV nor HPyV viral infection

The inhibitors of mutant BRAF that are used to treat metastatic melanoma induce squamoproliferative lesions. We conducted a prospective histopathological and molecular study on 27 skin lesions from 12 patients treated with vemurafenib. Mutation hot spots in HRAS, NRAS, KRAS, BRAF, and Pi3KCA were screened. HPV and HPyV infection status were also determined. The lesions consisted of 19 verrucal papillomas, 1 keratoacanthoma and 7 squamous cell carcinomas. No mutations were found within BRAF and NRAS. KRAS, HRAS, and Pi3KCA oncogenic mutations were found in 10 (83.3%), 7 (58.3%), and 4 (33.3%) patients respectively; however, these mutations were not consistent within all tumors of a given patient. Pi3KCA mutation was always associated with a mutation in HRAS. Finally, no correlation was found between the mutated gene or type of mutation and the type of cutaneous tumor or clinical response to vemurafenib. P16 protein level was not indicative of HPV infection. HPV was detected in only two lesions. Two cases had MCPyV, and one had HPyV7. In conclusion, neither HPV nor HPyV seem to be involved in the development of squamoproliferative lesions induced by verumafenib. By contrast, HRAS and KRAS play a predominant role in the physiopathology of these tumors.

Design, synthesis and biological evaluation of bis-aryl ureas and amides based on 2-amino-3-purinylpyridine scaffold as DFG-out B-Raf kinase inhibitors

By combining the scaffolds of UI-125 and Sorafenib, a series of bis-aryl ureas and amides based on 2-amino-3-purinylpyridine moiety were designed and synthesized as novel DFG-out B-Raf(V600E) inhibitors. Among them, 20c-e, 20g and 21h displayed potent antiproliferative activities against melanoma A375 (B-Raf(V600E)) cell lines with IC50 values of 3.190, 2.276, 1.856, 1.632 μM and 1.839 μM, respectively, comparable with the positive control Vemurafenib (IC50 = 3.32 μM). Selected compounds were tested for the ERK inhibition in human melanoma A375 (B-Raf(V600E)) and SK-MEL-2 (B-Raf(WT)) cell lines by Western blot. The results revealed that our compounds inhibited the proliferation of melanoma A375 cells (B-Raf(V600E)) through ERK pathway, without paradoxical activation of ERK in melanoma SK-MEL-2 cells (B-Raf(WT)). Eventually, 20g and 21h were selected to confirm their inhibitory effects on tumor growth in A375 xenograft models in mice. Compound 20g exhibited equivalent antitumor efficacy in vivo (T/C = 44.37%), compared to Sorafenib (T/C = 37.35%), by 23-day repetitive administration of a single dose of 50 mg/kg without significant body weight loss.

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.

Localized Epidermal Cysts as a Radiation Recall Phenomenon in a Melanoma Patient Treated with Radiotherapy and the BRAF Inhibitor Vemurafenib

BRAF inhibitors are broadly used for metastatic melanoma with BRAF mutations. Their use results in various cutaneous side effects, such as the development of keratoacanthomas and squamous cell carcinomas. We report a patient with metastatic melanoma treated with vemurafenib who developed dozens of histologically confirmed epidermal cysts within 2 months after initiation of vemurafenib administration. The cystic lesions were observed only in the localized area where a large exophytic melanoma tumor mass had been previously irradiated. Localized epidermal cysts may constitute an unusual radiation recall reaction in patients treated with BRAF inhibitors.

Clinico-morphological features of BRAF inhibition-induced proliferative skin lesions in cancer patients

BACKGROUND

The use of BRAF inhibitors may lead to the development of cutaneous toxicities such as rashes, photosensitivity, alopecia, palmoplantar erythrodysesthesia, and proliferative skin lesions, including keratoacanthomas (KAs) and cutaneous squamous cell carcinomas (cuSCCs). The latter are noteworthy for their potential to exhibit malignant features, and they may necessitate invasive treatment. Their prompt identification is of primary importance for directing supportive care efforts and maintaining dose intensity while minimizing the morbidity associated with supportive care interventions. Because such lesions are less familiar to oncologists, this study was designed to characterize their clinico-morphological features, which have not been hitherto described.

METHODS

The clinical and dermoscopic characteristics and risk factors of new-onset proliferative skin lesions (benign verrucous lesions and KAs/cuSCCs) developing after the initiation of treatment with vemurafenib, dabrafenib, and XL281 were analyzed; the histopathological diagnoses were ascertained.

RESULTS

The majority of the lesions were benign verrucous lesions (78%, n = 87), whereas KAs/cuSCCs represented 22% (n = 25). The median times to biopsy for the initial verrucous lesions and KAs/cuSCCs were 4.8 and 10.5 weeks, respectively. The clinico-morphological features significant for KAs/cuSCCs included a larger size (P < .001), a nodular appearance (P < .001), a central keratin plug (P < .001), a central ulceration or crust (P = .04), an adherent scale (P = .02), an erythematous halo (P = .03), and a scaly ring (collarette; P < .001) at the periphery.

CONCLUSIONS

Our findings represent the first detailed description of the clinico-morphological characteristics that permit distinction between the benign and malignant skin lesions induced by BRAF inhibitors. They are valuable for the recognition of lesions that require intervention and/or a dermatology referral versus those that permit provisional monitoring.

Intrinsic and acquired resistance to MEK1/2 inhibitors in cancer

Recent clinical data with BRAF and MEK1/2 [MAPK (mitogen-activated protein kinase)/ERK (extracellular-signal-regulated kinase) kinase 1/2] inhibitors have demonstrated the remarkable potential of targeting the RAF-MEK1/2-ERK1/2 signalling cascade for the treatment of certain cancers. Despite these advances, however, only a subset of patients respond to these agents in the first instance, and, of those that do, acquired resistance invariably develops after several months. Studies in vitro have identified various mechanisms that can underpin intrinsic and acquired resistance to MEK1/2 inhibitors, and these frequently recapitulate those observed clinically. In the present article, we review these mechanisms and also discuss recent advances in our understanding of how MEK1/2 inhibitor activity is influenced by pathway feedback.

Dabrafenib for the treatment of BRAF V600-positive melanoma: a safety evaluation

INTRODUCTION

V-raf murine sarcoma viral oncogene homolog B1 (BRAF) inhibitors are emerging as the standard of care for treating advanced melanomas harboring the BRAF V600 oncogenic mutation. Dabrafenib is the second approved selective BRAF inhibitor (after vemurafenib) for the treatment of unresectable or metastatic BRAF V600-positive melanoma.

AREAS COVERED

This review covers the current data on the efficacy and safety of the selective BRAF inhibitor dabrafenib in patients with metastatic BRAF V600 positive melanoma. The pharmacological, safety and efficacy data are discussed from Phase I, II, and III studies of dabrafenib monotherapy as well as in combination with the MEK inhibitor trametinib.

EXPERT OPINION

Dabrafenib has demonstrated comparable efficacy to vemurafenib in BRAF V600E mutant melanoma patients. Dabrafenib is well tolerated in patients with metastatic melanoma, including patients with brain metastases. Nevertheless side effects are common, but usually manageable. In the Phase III study testing dabrafenib, 53% of patients reported grade 2 or higher adverse events (AEs). Toxicities were similar to those seen in the early-phase trials, with the most common being cutaneous manifestations (hyperkeratosis, papillomas, palmar-plantar erythrodysesthesia), pyrexia, fatigue, headache, and arthralgia. Combining a BRAF inhibitor with a MEK inhibitor, which may block paradoxical MAPK activation in BRAF wild type (skin) cells, may lower the incidence of squamoproliferative eruptions.

Vemurafenib: an evidence-based review of its clinical utility in the treatment of metastatic melanoma

The discovery of BRAF mutations in the majority of patients with metastatic melanoma combined with the identification of highly selective BRAF inhibitors have revolutionized the treatment of patients with metastatic melanoma. The first highly specific BRAF inhibitor, vemurafenib, began clinical testing in 2008 and moved towards a rapid approval in 2011. Vemurafenib induced responses in ~50% of patients with metastatic BRAF-mutant melanoma and demonstrated improved overall survival in a randomized Phase III trial. Furthermore, vemurafenib is well-tolerated with a low toxicity profile and rapid onset of action. Finally, vemurafenib is active even in patients with widely metastatic disease. Despite the success of vemurafenib in treating patients with BRAF-mutant metastatic melanoma, most, if not all, patients ultimately develop resistance resulting in disease progression at a median time of ~6 months. Multiple mechanisms of resistance have been described and rationale strategies are underway to combat resistance. This review highlights the development, clinical utility, resistance mechanisms, and future use of vemurafenib both in melanoma and other malignancies. We consulted PubMed, Scopus, MEDLINE, ASCO annual symposium abstracts, and http://clinicaltrials.gov/ for the purpose of this review.

Managing the skin toxicities from new melanoma drugs

Patients treated with ipilimumab or targeted inhibitors of the RAF-MEK-ERK pathway (vemurafenib, dabrafenib, and trametinib) for advanced cutaneous melanoma often experience drug-related skin toxicities denoted as dermatologic adverse events (DAEs). Although rarely life-threatening, DAEs may emerge dramatically and potentially compromise oncologic therapy if not managed in a timely and effective manner. Early recognition of DAEs is critical to providing optimal skin care and prompt consultation with a dermatologist should be obtained when a diagnosis is unclear. The expanding utilization of new melanoma drugs compels physicians to maintain a watchful eye for both known and novel DAEs and to adopt a low threshold to biopsy worrisome skin findings. Numerous therapeutic options are available to manage DAEs including topical and systemic agents as well as surgical and destructive modalities. Applying such methods improves overall patient care and optimizes the effectiveness of new therapies for advanced cutaneous melanoma.

Genetic alterations and personalized medicine in melanoma: progress and future prospects

High-throughput sequencing technologies are providing new insights into the genetic alterations involved in melanomagenesis. It appears likely that most genetic events important in the pathogenesis of melanoma will be discovered over the next few years. Genetic analysis is also increasingly being used to direct patient care. In parallel with the discovery of new genes and the elucidation of molecular pathways important in the development of melanoma, therapies targeting these pathways are becoming available. In other words, the age of personalized medicine has arrived, characterized by molecular profiling of melanoma to identify the relevant genetic alterations and the abnormal signaling mechanisms involved, followed by selection of optimal, individualized therapies. In this review, we summarize the key genetic alterations in melanoma and the development of targeted agents against melanomas bearing specific mutations. These developments in melanoma serve as a model for the implementation of personalized medicine for patients with all cancers.

Vemurafenib cooperates with HPV to promote initiation of cutaneous tumors

Treatment with RAF inhibitors such as vemurafenib causes the development of cutaneous squamous cell carcinomas (cSCC) or keratoacanthomas as a side effect in 18% to 30% of patients. It is known that RAF inhibitors activate the mitogen-activated protein kinase (MAPK) pathway and stimulate growth of RAS-mutated cells, possibly accounting for up to 60% of cSCC or keratoacanthoma lesions with RAS mutations, but other contributing events are obscure. To identify such events, we evaluated tumors from patients treated with vemurafenib for the presence of human papilloma virus (HPV) DNA and identified 13% to be positive. Using a transgenic murine model of HPV-driven cSCC (K14-HPV16 mice), we conducted a functional test to determine whether administration of RAF inhibitors could promote cSCC in HPV-infected tissues. Vemurafenib treatment elevated MAPK markers and increased cSCC incidence from 22% to 70% in this model. Furthermore, 55% of the cSCCs arising in vemurafenib-treated mice exhibited a wild-type Ras genotype, consistent with the frequency observed in human patients. Our results argue that HPV cooperates with vemurafenib to promote tumorigenesis, in either the presence or absence of RAS mutations.