More than 80 percent of malignant melanoma patients in a recent study experienced a dramatic reduction in tumor size thanks to a new experimental drug treatment. While drug trials for the treatment are still in the early stages, industry experts such as Matthew Meyerson of the Dana Farber Cancer Institute in Boston report the findings as “a major breakthrough in cancer treatment.”
The findings of the study, published in a recent edition of the New England Journal of Medicine, are the result of targeted drug development. In previous genome analysis, it was found that production of a protein called BRAF is overactive in approximately 50 to 60 percent of patients diagnosed with malignant melanomas. This insight led to the production of drugs that inhibit the molecular pathways associated with BRAF production.
Two pharmaceutical companies ñ Roche and Plexxikon ñ collaborated to develop the specific drug used to hinder BRAF pathways. For the study, 32 melanoma patients were given the drug, with 81 percent showing a partial or complete response. In a few cases, tumors actually disappeared altogether for a short time.
The drug shows significant promise for a cancer that is notoriously difficult to treat. If caught early, surgery may prove an effective treatment. However, cases in which the cancer grows beyond the skin come with a poor diagnosis (many patients do not survive more than 12 months once metastasis occurs). Presently, only 10 to 20 percent of patients respond well to FDA approved drug treatments.
Thanks to the innovation of targeted genome sequencing, the number of participants in clinical trials can be greatly reduced. Given the promising effects of the phase II trial, the drug is ready to enter phase III trials to further test its efficacy. Of primary concern for future trials, is the analysis of a cancer’s ability to become resistant to the new drug. Current tests indicate that resistance can occur anywhere from three months to two years from the beginning of treatment.
To counter this resistance, researchers may try a combination of drugs that target additional protein mutations beyond the BRAF protein.
If found effective, the potential of BRAF inhibitor drugs may extend beyond malignant melanoma cancer. The mutation is also present in seven to eight percent of all other cancers.