14 DAY TRIAL // The median survival rates of metastatic melanoma patients can be increased by half, say researchers at the University of California in Los Angeles (UCLA), if sufferers are treated with the drug vemurafenib (Brand name Zelboraf). The chemical was recently approved for use in humans.
The new medication is especially well suited to fighting melanoma – a type of skin cancer – that emerges as the result of a common mutation affecting the BRAF protein. Researchers have already concluded a Phase II clinical trial, which was conducted on 132 patients over more than a year.
This investigation was coordinated by scientists at the UCLA Jonsson Comprehensive Cancer Center (JCCC), but included experts from other universities and research groups, in the US and Australia.
In advanced forms of melanoma, cancer spreads to other organs, leading to metastasis. This is usually the stage when all cancers become incurable. Patients with metastatic melanoma don't usually survive for more than nine months.
According to the JCCC team, patients who were administered Zelboraf exhibited a median survival rate of nearly 16 months. “This study shows that Zelboraf changes the natural history of this disease,” says UCLA professor of hematology–oncology Dr. Antoni Ribas, who is a researcher at the Center.
The investigator is also the senior author of a research paper describing the findings, which is published in the February 23 issue of the prestigious New England Journal of Medicine (NEJM).
“This data is beyond what I would have expected. We're seeing a significant number of patients with durable responses to the drug, and that the whole group of treated patients is living longer,” he adds.
“These results tell us that this drug is having a very big impact, and this changes the way we treat metastatic melanoma,” Ribas goes on to say. He adds that roughly 50 percent of metastatic melanoma patients display the mutated form of the BRAF protein.
Of those who take Zelboraf, nearly 53 percent display tumor reductions larger than 30 percent. The clinical trial revealed that about 14 percent of these patients exhibit no response to the medication.
“We knew this drug would make the melanomas shrink in a large proportion of patients and that it worked better than chemotherapy. This study confirmed that patients taking Zelboraf are living longer,” Ribas adds.
However, the expert and his team are also the authors of a study published in the January 19 issue of NEJM, which shows that administering vemurafenib to patients increases their likelihood of developing secondary cancers.
But blocking the mutated BRAF protein triggers the onset of a cascade of events in skin cells that are also prone to cancer-like mutations. This sets the stage for secondary cancers of a different type, which now find it a lot easier to grow.
“We looked at what was likely making them grow, and we discovered that the drug was making preexisting cells with a RAS [protein] mutation grow into skin squamous-cell cancers,” the team leader concludes.