Sept. 23, 2009 (Berlin) -- An experimental drug appears to dramatically and rapidly shrink deadly skin cancer tumors, researchers report.
Tumors shrank in 17 of 27 patients with advanced melanoma given the new pill, known as PLX4032. In two patients, the tumors completely disappeared.
The results are "unprecedented," says Paul Chapman, MD, of Memorial Sloan-Kettering Cancer Center in New York.
In one patient who underwent before-and-after imaging scans, the tumor "completely healed. I've never seen anything like it," he tells WebMD.
"We began to see signs of tumors turning off within two weeks," Chapman adds.
Overall, tumors shrank in 70% of patients with a particular cancer-related mutation who were given the pill.
In contrast, chemotherapy drugs used to treat advanced melanoma shrink only about 15% of tumors, according to Chapman.
The new pill was well tolerated, with no patients dropping out due to side effects.
The findings were presented at a joint meeting of the European Cancer Organization (ECCO) and the European Society of Medical Oncology.
Melanoma is the deadliest type of skin cancer, with about 160,000 new cases diagnosed worldwide each year. It is treatable if caught early, but once it spreads, it is rarely cured and typically kills within a year.
This year, there will be an estimated 68,720 new cases and 8,650 deaths from the disease in the U.S., according to the American Cancer Society.
The new drug blocks the activity of gene called BRAF that is involved in 50% to 60% of melanomas.
ECCO President Alexander Eggermont, MD, says the results are "simply spectacular."
Earlier research showed that patients who did not have a mutated BRAF gene did not respond to the drug, he says. "It's a targeted drug that makes sense. We know exactly what we are targeting, that is what all the excitement is about," Eggermont tells WebMD.
Chapman and colleagues are planning a study of 90 patients starting at the end of 2009 and a larger international trial involving several hundred patients in early 2010.
Plexicon, which makes the new drug and has licensed it to Roche, funded the work.