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Promising new melanoma drug cuts tumors by 80%
by Jamie Anderson - August 26, 2010 - comments
Malignant melanoma is serious and difficult to treat. For patients with advanced melanomas, the prognosis for survival is usually nine months or less. Sun exposure is the biggest cause of melanoma and other skin cancers.
Advanced melanoma often proves fatal, and this brutal skin cancer often kills within nine months of diagnoses. But an experimental drug from Roche (ROG.VX) and Plexxikon is giving rare hope to doctors and patients.
Clearing its Phase I clinical trial, the experimental drug successfully shrank deadly tumors in up to 80 percent of the patients.
The drug, called the PLX4032, targets the protein "BRAF," known to feed the cancerous growths.
Researchers say that 26 of 32 melanoma patients who had the key gene mutation in their tumors reportedly improved after the orally-administered medication.
"It worked: 81 percent had a partial response -- which has never been seen. I don't know of any solid tumors that have a response rate that high." -- Dr. Paul Chapman, senior author of a study
Details of the study
Fifty five patients with advanced melanoma participated in the Phase I clinical trial of the drug. All patients received gradually escalating doses of the drug. A twice-daily dose of 960 milligrams, however, proved optimal.
Ten of the 16 patients carrying the BRAF gene mutation showed a partial response to the drug, with their tumors shrinking by at least 30 percent. One patient completely responded to the treatment, with the tumor disappearing altogether.
In the second stage, among 32 patients with BRAF-mutated melanoma, 24 posted a partial response and two recovered completely, researchers say.
"It worked: 81 percent had a partial response -- which has never been seen. I don't know of any solid tumors that have a response rate that high," said Dr. Paul Chapman, senior author of a study.
"What's different here is that we've discovered a molecule that is responsible for driving the melanoma cell. It turns out that the melanoma really cares if we block the gene BRAF. It matters. It's addicted to this pathway," he added.
Furthermore, the drug proved effective in shrinking metastatic tumors at all sites of affliction, including the liver, small bowel, bone, and thyroid, the researchers said.
Short lived advantage
The benefits of the drug, however, were temporary, typically lasting for only about six months, Dr. Keith Flaherty of the Massachusetts General Hospital in Boston averred.
Thus, combining the drug with other currently available cancer treatments can produce a long-lasting effect, researchers hope.
Is it the cancer wonder drug?
But it’s too soon to predict whether the drug will actually be a "wonder drug" for cancer patients.
"I don't want to say this is going to change survival rates but they're working with the most ill people, so you can't really generalize (to other patient populations)," said Dr. Alice Pentland, chair of dermatology at the University of Rochester Medical Center. "I think the most important part of this breakthrough is the bigger percentage of people who responded."
The drug now enters the final, phase III clinical trial.
The findings of the study are published in the Aug. 26 issue of the New England Journal of Medicine.