Small-scale trials of two experimental treatments for skin cancer that have been tailored to target a particular patient’s tumours have proved safe with results showing promises.
These are the first drug trials in humans with personalised vaccines directed at neoantigens — molecules, caused by DNA mutations, found in cancer cells. The results of both were published in the journal Nature. The vaccines also triggered an immune response to tumor cells, they said, although this does not necessarily equate to a cure.
Unlike a traditional vaccine that prevents disease, the aim of NeoVax is to prevent cancer from recurring in melanoma skin cancer patients after their tumours have been surgically removed.
The customized vaccines are an emerging class of therapies that take advantage of neoantigens, proteins that appear on tumors and seem to be specific to each cancer patient. To make the vaccines, researchers first sequenced DNA and RNA extracted from each patient’s tumor. They then used computer algorithms to analyze the mutations on each tumor and predict the best targets that code for neoantigens. Based on that data, they created a personalized vaccine containing up to 20 of these neoantigens. Each patient received several injections of the vaccine over a few months.
In the two trials, researchers designed the vaccines to have multiple neoantigens specific to each patient. Because neoantigens appear only on tumor cells and not on healthy ones, researchers think an injection of neoantigens should look foreign to the immune system and help launch an attack on the cancer cells.
One major question about individualized cancer vaccines is whether they’re practical on a large scale. Traditionally, medicines are manufactured in large batches and can be taken off the shelf to treat any patient. Personalized cancer vaccines would need to be tailored to each patient.