New Hope in Glioblastoma Brain Tumor Treatment: The pp65K Cancer Vaccine

The newly developed pp65 cancer vaccine for glioblastoma multiforme (GBM-IV) was observed to prolong survival when given with temozolomide chemotherapy.

Glioblastoma multiforme (GBM-IV) is the most common adult brain cancer type. Although treatment advances have occurred over the last 20 years, they remain insufficient because the disease progresses rapidly.

A disease with a similarly aggressive course, Malignant Melanoma, was very difficult to treat until ten years ago, but new research and development have greatly improved the situation. Targeted and immune-directed GBM research is showing promising advances, as happened in Malignant Melanoma.

In recent years, advances in immunotherapies—treatments activating the body’s defenses against cancer—have been dazzling. They may remove brakes on immune cells or take the form of personalized cancer vaccines. Today we discuss a dendritic-cell vaccine developed with the cancer-specific protein pp65, a cancer vaccine which we will describe.

Study

New research observed pp65 protein production in %90 of glioblastoma cells and explored how this could be used in treatment. Human cytomegalovirus (CMV) also produces pp65, preventing immune responses against CMV. Researchers used it to develop a dendritic-cell vaccine against the disease.

This American study found high-dose temozolomide more effective when combined with vaccination against the glioblastoma-specific pp65 antigen. The Phase I study included newly diagnosed glioblastoma patients averaging 55 years of age, totaling 11. They received temozolomide and at least 7 cycles of pp65 vaccine, aiming to stimulate immunity against pp65 and destroy cancer cells containing it.

With this new treatment, duration of benefit (time to progression) rose to 25 months and overall survival to 41 months. Remarkably, among 11 postoperative participants, 4 had no progression for 59 to 64 months. These successful results are far longer than the survival provided by existing treatments for this difficult disease.

Although we cannot achieve absolute success in glioblastoma treatment, we anticipate this vaccine targeting pp65 will offer hope. Remember that the study had very few patients and is not strong enough to change routine practice. We will follow further research and share developments. .

Further Reading: Dendritic Cell Cancer Vaccines

Dendritic cells are a type of white blood cell, also called antigen-presenting cells. Their main task is to activate immunity against infection by producing antigens or presenting them to other immune cells. Dendritic cancer vaccines are made by mixing cancer cells or cancer-specific structures (such as the pp65 protein discussed here) with dendritic cells in the laboratory. Activated by tumor antigens, the cells are returned to the patient to help immunity recognize and destroy cancer cells. These vaccines are personalized. The FDA-approved prostate cancer vaccine Sipuluecel-T (brand name Provenge®) is the best-known example.