Tumors were completely wiped out in three of nine people with advanced melanoma who were given the drug for two weeks.
"Their tumors, which you could see outside the body before treatment, completely disappeared," James Goydos, MD, tells WebMD. Goydos is a surgical oncologist at the University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School in New Brunswick.
In two more patients, imaging scans showed that tumors had shrunk. Three more patients remained stable. One patient got worse, with signs of tumor growth.
The researchers tracked the patients' progress before and after the treatment with biopsies and PET scans, a form of nuclear-medicine imaging typically used to detect cancer.
The results were presented at the annual meeting of the American Association for Cancer Research.
Riluzole Lowers Glutamate Levels
Each year, more than 53,600 people in the U.S. are diagnosed with melanoma, according to the National Cancer Institute (NCI). In the past 30 years, the number of Americans who develop melanoma annually has more than doubled.
In about 70% of cases, people with melanoma develop lesions in body areas that are exposed to the sun. The cancer can then spread to other parts of the body -- typically the lymph nodes first and then other organs.
The new study involved people whose disease had spread, or metastasized, to the lymph nodes.
The work builds on the research team's earlier discovery that melanoma cells release a lot of a substance called glutamate.
Too much glutamate can overstimulate brain cells to the point that they burn out -- a possible explanation of what happens in ALS, says Suzie Chen, PhD, a professor of chemical biology at Rutgers University.
Riluzole, also sold as Rilutek, fights ALS by lowering glutamate levels. "So my collaborators said, let's test it against melanoma. And much to our surprise, the drug slowed the growth rate of melanoma cells [in the test tube]," Chen says.