Review of the available data to best guide initial treatment choice and the sequence of treatments for patients with BRAF Val600 mutant melanoma.
A clinical trial found that dabrafenib, a BRAF inhibitor, was far more effective in treating melanomas that have BRAF mutations than the chemotherapy drug dacarbazine, according to a report at an American Society of Clinical Oncology meeting. Patients treated with this drug lived without getting worse for 70% longer than those treated with dacarbazine (5.1 vs. 2.7 months, respectively). Moreover, compared to those treated with vemurafenib in other studies, dabrafenib-treated patients had less risk of another kind of skin cancer called squamous cell carcinoma. This suggests that dabrafenib, which is experimental, could be safer than vemurafenib, which is FDA approved.
A New England Journal of Medicine study found that vemurafenib, which was approved by the FDA in 2011, controlled melanomas in about half of people who had been previously treated for this disease. The trial included 132 repeat patients; tumors shrank in 47% of the patients and were not evident in 6% during the course of the trial. Vemurafenib is a BRAF inhibitor and about half of melanoma patients have BRAF mutations. While 26% of patients developed another kind of skin cancer called squamous cell carcinoma, these lesions were successfully removed surgically.
Primary source: http://www.nejm.org/doi/pdf/10.1056/NEJMoa1112302
Preliminary results suggest that an imaging technique can give early signs of drug resistance in melanomas. A Journal of Clinical Oncology study found that positron-emission tomography (PET)/computed tomography (CT) scans correlated with standard measures of tumor response in seven melanoma patients treated with vemurafenib. The scans also showed that during the third and fourth weeks of treatment, tumors in three patients began to take up and metabolize more of a sugar. This is a sign of cell activity, suggesting that these tumors were starting to resist the drug.
Vemurafenib increases the effectiveness of a treatment that uses immune system cells modified to target cancer cells, according to a study in Cancer Research. When combined with vemurafenib, which targets melanomas with the most common BRAF mutations (V600), this immunotherapy treatment killed more melanoma cells in mice. The combination treatment was also more successful than vemurafenib alone. The researchers conclude that their work supports testing this combination treatment in people with melanomas that have BRAF V600 mutations.