A breakthrough in cancer treatment

Advances in genetic technologies have allowed scientists to study the genetic mutations that underlie cancer in much greater detail. The result has been a new approach to drug design. Unlike chemotherapy, which can affect both healthy and cancerous cells and often triggers serious side effects, genetically targeted drugs act selectively on cancer cells that carry the mutation.

Now comes news of an experimental drug designed to block the effects of a genetic mutation often found in patients with malignant melanoma, a deadly cancer with few existing treatments, Technology Review reports.

The drug significantly shrank tumors in about 80 percent of those who carried the mutation. The findings signal a major success for so-called targeted cancer therapies, which are designed to block the effects of genetic mutations that drive the growth of cancer cells.

"This study is a major breakthrough in cancer treatment, and for metastatic melanoma," says Matthew Meyerson, an oncologist and researcher at the Dana Farber Cancer Institute in Boston. "It's a spectacular example of how genome-targeted therapies are beginning to help cancer patients."

In this study, 37 of 48 patients with the mutation responded to the new experimental drug, with their tumors shrinking by more than 30 percent. Tumors completely disappeared in three of those patients. About 30 percent of patients who took the drug the longest developed a specific type of squamous cell carcinoma, a tumor that usually doesn't spread and typically resolves on its own. 

Image: A PET scan of one melanoma patient shows a significant decrease in the size and number of tumors (shown in black) 15 days after treatment with an experimental drug.