A New England Journal of Medicine study reports a promising new approach to treating melanomas with BRAF mutations, which often respond to BRAF inhibitors for just a short time. Melanoma patients treated with trametinib were stable (ie, did not get worse) for three times longer than those treated with dacarbazine, a conventional chemotherapy drug (4.8 vs. 1.5 months, respectively). Trametinib inhibits MEK, a protein that is activated by BRAF and is involved in cell division. The drug’s most common side effects were rash, diarrhea, and swelling in the legs, which could be controlled by periodically adjusting the dose.
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.
Researchers identified a new mutation (BRAF L597) in a melanoma patient and then tested for it in 49 other melanomas that had no known cancer-linked mutations, which account for about half of all melanomas. They found that BRAF L597 occurred in 4% of the other melanomas tested. The study, which appeared in Cancer Discovery, also showed that tumors with this mutation respond to a MEK inhibitor called TAK-733. The existence of a targeted treatment, coupled with the new mutation’s relatively high incidence, lead the researchers to suggest routinely screening melanomas for BRAF L597.
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.
The National Institute for Health and Clinical Excellence (NICE) recommends giving people in England and Wales access to vemurafenib and ipilimumab via the National Health Service (NHS). The FDA has already approved these drugs for treating metastatic melanoma in the U.S. Initially, the cost of these treatments was a stumbling block in the UK and the watchdog institute’s recommendation comes with the caveat that manufacturers must provide a discount to the NHS.
People with melanoma lived longer when treated with a combination of dabrafenib (a BRAF inhibitor) and trametinib (a MEK inhibitor) than with dabrafenib alone, according to research in The New England Journal of Medicine. The study included 247 people with melanomas that had BRAF V600E mutations. Treatment with both drugs increased survival to 9.4 months, compared to 5.8 months with dabrafenib alone. In addition, tumors were not evident or shrank considerably in 76% of people treated with both drugs compared to 54% of those treated with dabrafenib alone.
An ongoing clinical trial found that 26% of melanoma patients treated with vemurafenib (Zelboraf®) were alive at 3 years—far longer than the average survival time of 9 months with conventional chemotherapy. Vemurafenib is a BRAF inhibitor and this trial includes 32 people with the most common BRAF mutation (V600E). In addition, five people survived at 3 years and 4 months; three of them had no evidence of disease.
A melanoma patient treated with vemurafenib also developed leukemia temporarily, according to a case report in The New England Journal of Medicine. This drug was already known to cause squamous cell skin cancers in some people with melanomas that have BRAF mutations. Vemurafenib activates proteins called extracellular signal-regulated kinases (ERK), which are involved in cell division and can lead to cancer in cells that have RAS mutations. The leukemia in the vemurafenib-treated patient had a RAS mutation and disappeared after treatment ended. The patient’s melanoma tumors, which did not have a RAS mutation, shrank during treatment.
A new blood test could show whether melanomas are likely to return in patients who are clinically free of the disease, according to a study in the Journal of Clinical Oncology. Cancer cells that break off tumors can enter blood vessels; this test identifies three tumor cell biomarkers in blood. The researchers periodically tested blood samples of 322 patients and found those with up to one cancer biomarker were more likely to be melanoma-free compared to those with two or more cancer biomarkers (73% vs 59%). This test could show which patients would benefit from aggressive treatments.