Tailor-made cancer vaccines that target unique genetic errors in a patient’s tumour have been developed in the US. Safety tests on three people, published in the journal Science, showed the immune system could be trained to fight skin cancers. The American team say the early results mark a “significant step” towards personalised cancer vaccines.
The charity Cancer Research UK called the tests an “exciting but very early-stage trial”. UV light can transform healthy skin cells into deadly melanomas by damaging the DNA.
The tumours are a genetic mess, containing hundreds of random mutations that are different in every patient. The mutations can change the proteins that stick out from the surface of cells and act like identifying flags. The team, mainly based in St Louis and Oklahoma City, analysed the genetic mutations to predict the new and unique flags that would be flown by the cancer cells.
A computer algorithm then analysed the new flags, known as neoantigens, to decide which would be the best targets for a vaccine. Personalised vaccines were given to three patients with advanced tumours in 2013. All had already been treated with another therapy – ipilimumab. One was in remission and has stayed cancer-free; another still has stable tumours; and the third patient’s tumour shrank in the months after the vaccine before returning to its original size and remaining stable.