Tumor vaccines can help the body fight cancer. Mutations in the tumor genome often lead to protein changes that are typical of cancer.
A vaccine can alert the patient’s immune system to these mutated proteins.
In a new study, researchers found a mutation-specific vaccine against malignant brain tumors is safe and triggered the desired immune response in the tumor tissue.
The research was conducted by a team from Heidelberg and Mannheim.
Diffuse gliomas are usually incurable brain tumors that spread throughout the brain and are difficult to remove completely by surgery.
Chemotherapy and radiotherapy often have only a limited effect. In many cases, diffuse gliomas share a common feature: In more than 70% of patients, the tumor cells have the same gene mutation.
In the study, the team wanted to support patients’ immune systems and use a vaccine as a targeted way of alerting them.
The IDH1 mutation is a particularly suitable candidate here, as it is highly specific to the gliomas and does not occur in healthy tissue.
Moreover, the IDH1 mutation is responsible for the development of these gliomas. That means that a vaccine against the mutated protein allows scientists. to tackle the problem at the root
The researchers tested the mutation-specific vaccine for the first time in a phase I study in patients newly diagnosed with an IDH1-mutated glioma.
A total of 33 patients at several different centers in Germany were enrolled in the study.
In addition to the standard treatment, they received the peptide vaccine. The immune response was evaluated in 30 patients.
The team did not observe any serious side effects in any of the patients who were vaccinated.
In 93% of the patients, the immune system showed a specific response to the vaccine peptide and did so regardless of the patient’s genetic background.
In many vaccinated patients, the team found swelling of the tumor caused by a host of invading immune cells.
These patients had a particularly large number of T helper cells in their blood with immune receptors that responded specifically to the vaccine peptide.
This shows that the activated mutation-specific immune cells had invaded the brain tumor tissue.
The three-year survival rate after treatment was 84% in the fully vaccinated patients, and in 63% of patients, tumor growth had not progressed within this period.
Among the patients whose immune system showed a specific response to the vaccines, a total of 82% had no tumor progression within the three-year period.
The team says the safety and immunogenicity of the vaccine were so convincing that they continued to pursue the vaccine concept in a further phase I study.
The researchers are also preparing a phase II study to examine for the first time whether the IDH1 vaccine leads to better treatment results than the standard treatment alone.
The study is published in Nature. One author of the study is Michael Platten.
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