14 DAY TRIAL // A pill developed to combat a type of skin cancer called melanoma manages to treat the condition, but boosts patients' risks of developing secondary, different types of skin cancer. The substance is called vemurafenib, and is sold under the brand name Zelboraf.
When oncologists recommend this therapy to their patients, they recommend them to take the pill twice daily. Researchers at the University of California in Los Angeles (UCLA) and international partners have now shown that doing so boosts secondary cancer risks.
The investigation was carried out by scientists at the UCLA Jonsson Comprehensive Cancer Center (JCCC), the London, UK-based Institute of Cancer Research and the company Plexxikon.
Together, the researchers were able to shed light on the mechanism causing this unfortunate link. Zelboraf was demonstrated to facilitate the development of skin squamous-cell carcinomas, even as it was inhibiting the growth and development of melanomas.
In order to understand the results, it's important to know that vemurafenib acts by blocking a mutated form of the BRAF protein. In melanoma patients, these molecules drive the growth and spread of the actual tumors. If left untreated, this type of cancer can metastasize.
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.
Details of the new study appear in the January 19 issue of the prestigious New England Journal of Medicine. UCLA professor of hematology–oncology Dr. Antoni Ribas was a coauthor on the paper.
“We wondered why it was that we were treating and getting the melanoma to shrink but another skin cancer was developing,” explains the scientist, who also holds an appointment at the JCCC.
“We looked at what was likely making them grow, and we discovered that the drug was making preexisting cells with an RAS mutation grow into skin squamous-cell cancers,” he explains.
Using the new data, oncologists and cancer researchers may now move forth with developing new types of inhibitor drugs, which will not feature adverse side-effects.