Giving melanoma patients a break from vemurafenib could make this treatment more effective. Research in Nature shows that vemurafenib-resistant tumors keep growing during treatment because they produce high levels of mutated BRAF proteins, which are involved in cell division. Moreover, these tumors actually depend on the drug to grow. In contrast, an on-and-off treatment schedule can help keep melanomas from becoming resistant to vemurafenib in mice.
A British Medical Journal report questions an invasive, expensive standard practice for melanoma patients in the U.S. Called sentinel node biopsy, the approach involves testing lymph nodes near tumors for cancer cells and removing nodes that test positive. The report cites a 2006 study showing that sentinel node biopsy did not increase 5-year survival rates and calls for further analysis of the practice’s effectiveness. Sentinel node biopsies are not standard in the UK.
Based on current data, researchers have developed a new treatment guide for melanomas with the most common mutations (BRAF V600). While these melanomas can be targeted with vemurafenib and dabrafenib, challenges remain. Not all tumors respond, some become resistant, and side effects can include another type of skin cancer called squamous cell carcinoma. Other treatment options include trametinib, which targets a protein called MEK, as well as immunotherapies such as high-dose interleukin 2 and ipilimumab, both of which can control tumors completely.
A JAMA Surgery study clarified when melanoma is likely to return in people determined to be cancer-free by sentinel lymph node biopsy. The researchers found that melanoma recurred in 16% of 515 such patients and that 4% of them had tumors in the lymph nodes that had been tested. Recurrence was more likely when the initial tumors were on the head or neck and were deeper (2.7 vs. 1.8 mm). Recurrence was less likely in women and in people who were younger when first diagnosed.
A JAMA Dermatology study shows the dangers of using smartphone apps to self-diagnose melanomas. The researchers compared diagnoses of 60 melanomas and 128 benign lesions by a board-certified dermatopathologist to those of four apps. Three of the apps incorrectly said that 30% or more of the melanomas were harmless. The fourth app, which sent images to board-certified dermatologists, was better, but still misdiagnosed one of the melanomas as benign. These apps are not subject to regulatory oversight.
Pharmaceutical firm GlaxoSmithKline has started a phase III study to see if a drug combination can prevent or delay the recurrence of melanomas with BRAF V600 mutations. Both drugs—dabrafenib, a BRAF inhibitor and trametinib, a MEK inhibitor—are experimental; the study will assess the efficacy and safety of the combination. The researchers plan to enroll about 850 people from more than 200 sites worldwide in the study. Another pharmaceutical firm, Roche, is also doing late-stage trials of a different BRAF inhibitor/MEK inhibitor combination.
Biotech company Genentech has added a MEK inhibitor to a phase III trial of vemurafenib, an FDA-approved BRAF inhibitor. MEK inhibitors have been shown to counteract resistance to BRAF inhibitors. The experimental MEK inhibitor is called GDC-0973, and is also known as XL-518 or RG7421. Vemurafenib (Zelboraf®) targets melanomas with BRAF V600 mutations, which are found in about half of these aggressive skin cancers. Genentech is part of the Roche Group; the two companies are conducting this combination treatment trial jointly.