Incidence and characteristics of melanoma brain metastases developing during treatment with vemurafenib.

Vemurafenib is indicated for the treatment of patients with BRAF (V600)-mutant metastatic melanoma. We studied for the first time the characteristics of brain metastases developed during treatment with vemurafenib in real-life conditions. We included all patients treated over 3 years with vemurafenib in our department for metastatic melanoma without initial brain involvement. Our primary endpoint was to assess the incidence of brain metastases in these patients. Our secondary endpoints were to identify the risk factors for metastases occurrence and their characteristics and course. In our retrospective cohort of 86 patients, 20% had developed brain metastases on average 5.3 months after vemurafenib initiation. The median follow-up was 9 months (1-26 months). Radiological examinations revealed multiple brain metastases in 41% of patients. The only risk factor for metastasis occurrence identified was a high number of metastatic sites when initiating vemurafenib (p = 0.045). Metastasis development was associated with a trend toward a decrease in overall survival from 12.8 to 8.5 months (p = 0.07) and a significant decrease in progression-free survival from 7 to 5 months (p = 0.04). Among the patients who developed brain metastases, 82% died, of whom 64% within 3 months, versus 58% of patients without brain metastases over the same period. The extra-cerebral disease was well controlled in 59% of patients during brain progression. In vemurafenib-treated melanoma patients, brain metastases are frequent and associated with a particularly poor prognosis. Because of their high frequency in patients with controlled extra-cerebral disease, brain explorations should be systematically performed during treatment.