Gene Therapy Gives Hope in Virulent Form of Cancer

Feb. 25, 2010— -- Melanoma researchers are known to be a jaded bunch.

Despite years of research, the last significant new treatment for the severe form of skin cancer came out in 1992 -- and only 5 percent to 10 percent of cancer patients get any lasting results with that treatment.

The best doctors have been able to offer patients has been experimental medicine, "because there are no right answers," on how to treat melanoma that has spread to other organs, Dr. Anna Pavlik, director of the melanoma program at the New York University Cancer Institute.

But in 2008, patients enrolled in a clinical trial of an experimental drug called PLX4032 started to get better. Much better.

"I've never seen anything like this," said Dr. Jeffry Sosman, principle investigator of the recently completed phase II study the new drug. "I had patients who were in extreme pain and within a week or so, came to the office off of pain medicine."

Sosman said that drug, which is now known as RO5185426 is designed to hit the "Achilles' heel" of a tumor. The drug works by blocking the effects of the so-called BRAF genetic mutation discovered to be in melanoma tumors through the human genome project. Turn off the gene, and it will stop sending signals to the cells to grow uncontrollably.

About 70 percent to 80 percent of patients with the mutation saw their tumors regress, often by about 50 percent within months of trying the medicine, Sosman said. And unlike chemotherapy, which often works for six months or so before tumors grow again, most of the patients who tried RO5185426 are still waiting for the other shoe to drop.

Although the drug needs one more round of rigorous testing in a phase III trial before it could be approved for commercial use, the promise of new drug has caught the attention of the media and of melanoma researchers nation-wide. The New York Times first reported on the promising results of the drug trials.

Stephen Dixon, of Nashville, Tenn., said RO5185426 literally changed his view on life.