Melanoma brain metastases and vemurafenib: need for further investigation

Brain metastases are a major cause of morbidity and mortality in patients with advanced melanoma. With the development of targeted agents for the treatment of metastatic melanoma, a great deal of interest has focused on whether selective BRAF inhibitors may play a role in the treatment of brain metastases in lieu of or in addition to surgery and/or radiation therapy. However, relatively little is known about the intracranial effectiveness of vemurafenib, the only US Food and Drug Administration-approved selective BRAF V600E inhibitor, because patients with brain metastases have historically been excluded from vemurafenib clinical trials. We describe 3 patients with BRAF V600E mutation metastatic melanoma in whom treatment with vemurafenib resulted in prompt extracranial disease response but progression of metastatic disease in the brain. Further, we discuss possible mechanisms responsible for the suboptimal central nervous system response observed in these patients and alternative therapies for patients with melanoma metastatic to the brain.

A new era in the treatment of melanoma: from biology to clinical practice

Melanoma is the deadliest cutaneous malignancy and its incidence continues to grow. Until 2011, the treatment options for metastatic melanoma were scarce and without any overall survival benefit. The emergence of new targeted therapies for BRAF mutant melanoma (vemurafenib) and immunotherapy (ipilimumab) has changed the standard of care for this disease. The objective of the present review is to summarise the biological background of the new therapeutic approaches in melanoma, focusing on apoptosis resistance, immune modulation and angiogenesis, and the direct translation into clinical practice.

Neoplastic leptomeningitis presenting in a melanoma patient treated with dabrafenib (a V600EBRAF inhibitor): a case report

INTRODUCTION

Leptomeningeal metastases are occurring at higher frequency in cancer patients. The prognosis of leptomeningeal metastases is poor and standard treatment, which includes radiotherapy and chemotherapy, is mostly ineffective. Melanoma represents one of the tumors with the highest incidence of leptomeningeal metastases. For such a disease, the BRAF inhibitors have recently been demonstrated to be effective on melanoma brain metastases harboring the V600EBRAF mutation.

CASE PRESENTATION

We report a case of a 39-year-old Italian woman with advanced melanoma with brain, lung and peritoneum metastases harboring the V600EBRAF mutation. In August 2010 she was enrolled into the BRIM3 trial and after the randomization process she received dacarbazine. After two cycles, there was evidence of disease progression in her peritoneum and lung. For this reason, she was enrolled into another clinical trial with the GSK2118436 BRAF inhibitor, dabrafenib, as a second line of therapy. She had a partial response that was maintained until 13 weeks of treatment. In January 2011 she developed symptoms typical for brain metastases and received a diagnosis of leptomeningeal involvement of melanoma cells after an examination of her cerebral spinal fluid; magnetic resonance imaging was negative for meningitis or brain metastases. Analysis of her cerebral spinal fluid sample confirmed that the melanoma cells still carried the V600EBRAF mutation. After a few days, our patient went into a coma and died.

CONCLUSION

Starting with a clinical case, we discuss the pathogenesis of leptomeningeal metastases and whether the leptomeninges may represent a sanctuary where melanoma cells may generate resistance and/or BRAF inhibitors cannot reach an adequate concentration for significant activity. We assess whether treatment with BRAF inhibitors in melanoma patients should be interrupted as soon as disease progression appears or continued beyond progression, through the administration of additional compounds.