(Medical Xpress)—Australian researchers have given hope to patients with advanced melanoma by showing that a new drug targeting a common mutation in melanoma successfully shrank tumours that had spread to the brain.
The study is the largest conducted on melanoma patients with brain metastases and was led by researchers at the University of Sydney, Melanoma Institute Australia, Westmead Hospital and Westmead Institute for Cancer Research.
The results are published in The Lancet Oncology medical journal today.
"This is the largest evidence confirming that we have a systemic drug therapy that helps prolong survival in patients with multiple melanoma brain metastases. The findings are among the most important in the history of drug treatment for melanoma," said lead author Dr Georgina Long, from Sydney Medical School, the Melanoma Institute Australia and Westmead Hospital.
Nearly half of all patients with advanced melanoma will develop brain tumours - metastases - during the course of their disease. Until now, there have been very few effective treatment options.
The new drug called dabrafenib targets the V600E BRAF mutation that is active in half of melanoma cases. The drug is manufactured by GlaxoSmithKline which sponsored the study.
The latest findings build on the results of a smaller (Phase I) study published in May 2012 that revealed the drug the researchers had been testing to treat melanoma patients also had the ability to shrink secondary metastases in the brains of patients with advanced forms of the disease.
The Phase I trial showed brain metastases in nine of the 10 patients shrank within the first six weeks. All 10 patients survived beyond five months, two patients survived beyond 12 months. One patient was alive at 19 months.
The most recent (Phase II) trial divided patients into two groups - one group had never received prior treatment for brain metastases. The other had received prior treatment for brain metastases but they had since progressed (got worse).
The primary outcome of the study was the proportion of patients with the V600E BRAF mutation who responded to the drug and the researchers found that dabrafenib had activity in at least 30 percent of patients, with or without prior treatment.
Furthermore, in patients with the V600E BRAF mutation, intracranial disease control (one of the secondary outcomes) was achieved in 81 percent of patients who had no prior treatment for brain metastases and 89 percent of patients who had received prior treatment and progressed.
The researchers concluded that the drug may add months to the lives of patients whose melanoma has spread to the brain. Most patients with brain metastases don't survive past four months.
The study was a 172 patient Phase II multicentre open-label study at 24 hospitals across six countries.
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