For decades, scientists have been trying to develop treatments for glioblastoma (brain cancer) by activating a person's own anti-tumor immunity. As of 2024, there are still no approved (standard and common) methods. Glioblastoma immunotherapy is still in the status of an experimental medical field. As of 2024, a review of 6 phase III trials of glioblastoma immunotherapy has been published, 5 of which have not received regulatory approval, and the sixth is pending approval.
Glioblastoma therapy: where are we now?
Currently, glioblastoma is considered one of the most aggressive primary malignant brain tumors with a poor prognosis. It is an incurable disease for which physicians can only prolong the life of the patient.
Survival rates have been improving in the 21st century, with the first advances being made with temozolomide chemotherapy and the second with the use of constant electromagnetic fields (TTFs). Despite some improvement in prognosis with the introduction of advanced methods, the median survival rate for glioblastoma is 21 months, significantly less than for most other malignant tumors.
Features of immunotherapy for glioblastoma
Immunotherapy has not yet shown impressive results, but is considered a promising direction in the treatment of glioblastoma for a number of reasons:
1. The tumor microenvironment is immunosuppressive. It suppresses the immune response. This immunosuppressive environment is a potential target for immunotherapeutic agents that could remove this immunosuppression, thereby making the tumor vulnerable to attack by the immune system.
2. Glioblastoma is a genetically variable tumor. Brain cancer cells develop a variety of mutations and produce different types of abnormal proteins, which challenges targeted therapy. In these conditions, there is hope for immunotherapy, which works regardless of the genetic makeup of the tumor.
3. There is no need to cross the blood-brain barrier. This barrier separates the brain circulation from the rest of the bloodstream. Not all drugs can cross the blood-brain barrier, but immunotherapy does not need to because antigen presentation occurs outside the brain: in the lymph nodes of the head and neck.
Recently, immunotherapy has made significant progress in the fight against several types of cancer, further increasing interest in this strategy for glioblastoma. At the same time, immunotherapy for brain cancer is complicated by the need to use glucocorticoids in this group of tumors. Glucocorticoids suppress the immune system, reducing the effectiveness of immunotherapy. As a result, doctors must either withhold corticosteroids or use them in low doses.
Clinical trials of the effectiveness of immunotherapy
Results from six phase III trials testing the following drugs have recently been published:
- Epidermal growth factor receptor peptide vaccine (Rindopepimut)
- Immunogenic replicating retrovirus (Toca511)
- Immune checkpoint inhibitors (ICPIs) – three trials
- Autologous tumor lysate-loaded dendritic cell vaccine (DCVax-L)
Only dendritic cells showed encouraging results. One third of the treated patients achieved long-term survival rates. The median survival rate reached 22.4 months from the date of surgery versus 16.5 months in the control group. The survival rate beyond 30 months was 11%.
Trials of advanced glioblastoma immunotherapy agents are currently underway and will be published in the next few years. Dendritic cell-based vaccines, peptide vaccines, ICIs, and oncolytic viruses are being studied.
If you want to undergo glioblastoma treatment with immunotherapy methods, including the use of dendritic cells, you can go abroad. You are welcome to use the Booking Health service to choose a clinic. Here you can find out prices and get travel services.