The RAF inhibitors vemurafenib and dabrafenib are emerging as the standard of care for Val600 BRAF-mutant metastatic melanoma. These drugs have shown clinical benefit over the standard care (dacarbazine); however, they are associated with frequent cutaneous adverse events, which can be concerning to the patient and their physician. Herein, we review the range of cutaneous disorders that seem to be induced by RAF inhibitors, including cutaneous squamous-cell carcinoma, hyperkeratotic lesions, Grover's disease, keratosis pilaris-like reactions, and photosensitivity. These disorders often affect patients' quality of life; therefore, dermatological assessment and timely management is essential to ensure that patients continue to use RAF inhibitors.

Cutaneous toxicities of RAF inhibitors

The mitogen-activated protein kinase (MAPK) pathway is critical to oncogenic signaling in the majority of patients with malignant melanoma. Driver mutations in both NRAS and BRAF have important implications for prognosis and treatment. The development of inhibitors to mediators of the MAPK pathway, including those to CRAF, BRAF, and MEK, has led to major advances in the treatment of patients with melanoma. In particular, the selective BRAF inhibitor vemurafenib has been shown to improve overall survival in patients with tumors harboring BRAF mutations. However, the duration of benefit is limited in many patients and highlights the need for understanding the limitations of therapy in order to devise more effective strategies. MEK inhibitors have proven to particularly active in BRAF mutant melanomas also. Emerging knowledge about mechanisms of resistance as well as a more complete understanding of the biology of MAPK pathway signaling provides insight into rational combination regimens and sequences of molecularly targeted therapies.

MAP kinase signaling and inhibition in melanoma.

The purpose of this study is to review the development of BRAF inhibitors, with emphasis on the trials conducted with dabrafenib (GSK2118436) and the evolving role of dabrafenib in treatment for melanoma patients. Fifty percent of cutaneous melanomas have mutations in BRAF, resulting in elevated activity of the mitogen-activated protein kinase signaling pathway. Dabrafenib inhibits the mutant BRAF (BRAF(mut)) protein in melanomas with BRAF(V600E) and BRAF(V600K) genotypes. BRAF(V600E) metastatic melanoma patients who receive dabrafenib treatment exhibit high clinical response rates and compared with dacarbazine chemotherapy, progression-free survival. Efficacy has also been demonstrated in BRAF(V600K) patients and in those with brain metastases. Dabrafenib has a generally mild and manageable toxicity profile. Cutaneous squamous cell carcinomas and pyrexia are the most significant adverse effects. Dabrafenib appears similar to vemurafenib with regard to efficacy but it is associated with less toxicity. It is expected that new combinations of targeted drugs, such as the combination of dabrafenib and trametinib (GSK1120212, a MEK inhibitor), will provide higher response rates and more durable clinical benefit than dabrafenib monotherapy.

https://www.dovepress.com/getfile.php?fileID=14682

Dabrafenib and its potential for the treatment of metastatic melanoma

Efficacy and safety of ipilimumab 3 mg/kg in patients with pretreated, metastatic, mucosal melanoma

Background
Ipilimumab and vemurafenib have both been shown to improve survival in phase III trials of patients with metastatic melanoma. Although vemurafenib is associated with a rapid onset of activity, responses are often of limited duration. Conversely, responses to ipilimumab take time to develop, but can be durable. Currently, limited data exist on the sequencing of these agents in patients with the BRAFV600 mutation. The aim of this analysis was to identify factors that could potentially be used to optimise the order in which ipilimumab and BRAF inhibitors are administered in this patient population.

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Sequencing of BRAF inhibitors and ipilimumab in patients with metastatic melanoma: a possible algorithm for clinical use

LBA8500^ Background: Dabrafenib, a selective BRAF inhibitor, has shown activity with a manageable safety profile in phase I/II studies in patients (pts) with BRAFV600E-mutated metastatic melanoma (MM). This phase III trial (NCT01227889) compared progression-free survival (PFS) in pts with advanced MM treated either with dabrafenib or dacarbazine (DTIC). Methods: Pts with previously untreated, unresectable stage III or IV BRAFV600E-mutated melanoma were randomized (3:1) and stratified by stage to dabrafenib (150 mg po bid) or DTIC (1000 mg/m2, IV, q3w). Primary endpoint was investigator-assessed PFS. Primary analysis for PFS was planned after 102 events. Pts on the DTIC arm were allowed to cross over once progression was confirmed by independent review (IR). Secondary endpoints included PFS by IR, overall survival (OS), response rate (RR), duration of response, safety and pharmacokinetics. Results: 250 pts were enrolled at 93 centers globally from February to September 2011. 187 were randomized to dabrafen...

Phase III, randomized, open-label, multicenter trial (BREAK-3) comparing the BRAF kinase inhibitor dabrafenib (GSK2118436) with dacarbazine (DTIC) in patients with BRAFV600E-mutated melanoma.

Danielle Ouellet

Papers

Phase III, randomized, open-label, multicenter trial (BREAK-3) comparing the BRAF kinase inhibitor dabrafenib (GSK2118436) with dacarbazine (DTIC) in patients with BRAFV600E-mutated melanoma.