A clinical trial of a brain tumor vaccine reveals it to be safe and effective for treating malignant brain cancers.
Scientists at The German Cancer Research Center developed a brain tumor vaccine that targets mutated proteins specific to diffuse Gliomas. For the first time, researchers have now tested the vaccine in humans. Findings of the Phase I trial are available in the journal Nature.
A Glioma is a type of brain cancer that arises from glial cells within the brain or spine. Although rare, it forms 80% of all malignant brain tumors. Treatment options include a combination of surgery, radiotherapy, and chemotherapy. Since diffuse gliomas are usually spread out across the brain, standard therapeutic options don’t produce the desired effect. However, more than 70% of patients possess a specific mutation in the tumor cells. The mutation, which affects the enzyme isocitrate dehydrogenase 1 (IDH1), results in the formation of a novel protein called a neo-epitope.
However, this particular mutated protein is only present in tumor cells and results in the immune system recognizing it as foreign. As a result, the team of researchers aimed to develop a vaccine against this specific mutated protein to trigger the formation of antibodies. The fact that IDH1 is only present in gliomas and causes the development of brain tumor, made it the perfect candidate for a vaccine.
Our idea was to support patients’ immune system and to use a vaccine as a targeted way of alerting it to the tumor-specific neo-epitope.
Michael Platten, study director
82% of Patients Had a Complete Cessation of Tumor Growth
For the Phase 1 trial, the team recruited 33 patients with IDH1-mutated glioma. Along with the vaccine, the participants also received standard cancer treatments.
Researchers did not observe any side effects in any of the vaccinated patients. Findings revealed a vaccine-induced immune response in 93% of the patients. 82% of these patients had no tumor progression within the three years post-vaccine. Moreover, the 3-year survival rate was 84% in the vaccinated group. During this three-year interval, 64% did not experience a growth in their tumor.
We cannot draw any further conclusions about the vaccine efficacy from this early study without a control group. The safety and immunogenicity of the vaccine were so convincing that we continued to pursue the vaccine concept in a further phase I study
Michael Platten, study director
The researchers are now preparing for a phase II trial to compare the efficacy of IDH1 vaccine to that of standard treatment. A follow-on study is also in the works where the team will combine the brain tumor vaccine with checkpoint inhibitors.
Reference:
Platten, M., Bunse, L., Wick, A. et al. A vaccine targeting mutant IDH1 in newly diagnosed glioma. Nature (2021). https://doi.org/10.1038/s41586-021-03363-z
