WCCS/EADO 2016 | Vaccines for melanoma – how to help patients who don’t respond to treatment

Gerold Schuler, MD of University Hospital Erlangen, Erlangen, Germany discusses his talk on vaccines for melanoma held at the 2016 World Congress on Cancers of the Skin (WCCS) and the Congress of the European Association of Dermato-Oncology (EADO) in Vienna, Austria. First, Prof. Schuler points out that cancer vaccines in general have not been very succesful clinically, except for certain subgroups of patients. This was called the cancer vaccine paradox as the vaccines induced tumor specific T-cells but did not show much clinical efficacy. Melanoma was the model tumor because it is an immunogenic tumor. In retrospect, this was a mistake as there is spontaneous T-cell immunity in melanoma according to Prof. Schuler. This means, the tumor has had the chance to learn to surpress T-cells. Now, one can interfere with checkpoint blockade antibodies; when given to a melanoma patients, the breaks are removed and the T-cells already there get a push and this can lead to clinical improvement. When the two now approved antibodies are combined, only 60% of patients respond as Prof. Schuler points out. There is reason to believe, that if you combine checkpoint blockade with vaccines, the response rate to checkpoint blockade can be increased. According to Prof. Schuler, the question in melanoma is what to do with the 40% of patients who do not respond to treatment. There is not much hope to treat those patients with vaccination alone because this subset of patients has tumor microenvironment with a mesenchymal signature, that is so hostile that no T-cells are induced; and if there are T-cells, they are suppressed. Therefore, it is important to learn how to manipulate the microenvironemt and then vaccines will help these patients.