Personalized Cancer Vaccine Shows Promise

personalized cancer vaccine

Healthy Human T-cell. Credit: NIAID

 

A small clinical trial evaluating a personalized cancer vaccine shows promising results.

Recruiting your immune system to fight cancer isn’t a new concept. In recent years immunotherapy have been used to combat many forms of advanced cancers, but the treatment haven’t resulted in a panacea for all known forms of cancer as many hoped. Some already approved immunotherapies have managed to prolong survival in advanced forms of cancer but not cure it. Now a new study published in Science finds that a personalized cancer vaccine could help neutralize melanoma cells.

A Personalized Cancer Vaccine

T-cells are a specialized type of immune cell that can find and destroy both pathogens and malfunctioning cells in your body. Using a vaccine to activate these cells to attack cancer cells while leaving normal healthy cells intact is the key problem researchers work toward solving. One solution might be so-called neoantigens, unique peptides on the surface of cancer cells that make them different from normal healthy cells.

Neoantigens are the result of the high rate of mutation that takes place in cancer cells. These peptides are a great target for the immune system since they aren’t found on normal healthy cells, lacking the high rate of mutation. Unfortunately making a vaccine from these peptides is difficult since it has to be tailored to each cancer, a time-consuming and expensive process.

Making this personalized cancer vaccine is tricky. To find the novel peptides researchers have to sequence a lot of tumor DNA, an expensive process that wasn’t feasible until recently. Using this method researchers at Washington University in St. Louis have made personalized cancer vaccines targeting melanomas, a common type of skin cancer.

To make the vaccine researchers analyzed the DNA of melanoma tumors, isolated during surgery, in three patients to find the novel peptides used to create the personalized cancer vaccine. Seven peptides were selected for the patients and mixed with dendritic cells taken from the blood of the melanoma patients. This mixture was then re-injected into the patients to stimulate an immune response. This process was repeated three more times over several months to create the personalized cancer vaccines.

The vaccines had the desired effect. The peptides/white blood cells re-injected into the patients provoked a broad response among the T-cells in the patients.

After the study one patient was declared cancer free. The two other patients had inoperable tumors left in their body after the surgery to remove the primary tumor and 8-9 months after the vaccine was administered they hadn’t grown any further, though it’s hard to say this was because of the vaccine.

The results are promising and the personalized vaccine was deemed safe for use, though this trial only included three patients. Next a phase 1 trial on six patients has been approved by the FDA.