Early clinical trials of personalized skin cancer vaccine have produced highly promising results. The results of the first “tailor-made” vaccines against melanoma skin cancer have been seen to show a “very strong” immune response with no adverse side effects being observed in three patients in addition to boosting the number and diversity of immune system “killer T-cells” that typically attack tumors.
The researchers in this study, which was the first of its kind ever, tried customized vaccines on melanoma patients whose survival rates were as low as 10%, because of their cancer having spread to the lymph nodes.
The findings of the Phase I trial which were published in the journal Science have led the scientists following the developments to believe that customized immunotherapy could pave the way not only for melanoma but also other cancers.
“This proof-of-principle study shows that these custom-designed vaccines can elicit a very strong immune response,” said Dr Gerald Linette, from Washington University School of Medicine in St Louis, US, who led the trial.
“The tumor antigens (proteins) we inserted into the vaccines provoked a broad response among the immune system’s killer T-cells responsible for destroying tumors.
“Our results are preliminary, but we think the vaccines have therapeutic potential based on the breadth and remarkable diversity of the T-cell response.”
The new approach entailed mapping the DNA of individual patients’ tumors and the samples of their healthy tissue so as to pinpoint the proteins unique to cancer cells. This was in total contrast to previous cancer vaccines which were focused on normal proteins commonly present at high levels in particular kinds of tumor. The same proteins, however, are also found in healthy cells. And this made it difficult for these old school vaccines to trigger a potent immune response.
“This exciting but very early stage trial shows that it may be possible to create vaccines that are tailored to the specific genetic mistakes in a patient’s cancer,” said Dr Alan Worsley, senior science communications officer at Cancer Research UK.
“At the moment it’s not clear how effective this immunotherapy would be at killing cancer cells in the body and improving survival, but this promising study sets the stage for creating vaccines that are designed to target each patient’s individual tumor in the future.”
However, encouraged by the initial observations, the team hopes that the same approach could be used to treat lung, bladder and certain colorectal cancers in future.
