A combination of vaccine and chemotherapy sessions may help improve both progression-free survival and overall survival rates for patients suffering from glioblastoma -- a malignant tumour affecting the brain or spine, researchers say.

In a clinical trial, 11 patients received a vaccine targeting cytomegalovirus (CMV) antigen pp65, combined with high-dose chemotherapy (temozolomide).

The results, published in the journal Clinical Cancer Research, demonstrated a median progression-free survival of 25.3 months and a median overall survival of 41.1 months in eight patients.

In the remaining three patients, the disease was progression-free for more than seven years after diagnosis, the researchers said.

"The clinical outcomes in glioblastoma patients who received this combination were very striking," said lead author Kristen Batich from the Duke University in North Carolina, US.

The typical median survival for glioblastoma patients is less than 15 months.

To overcome these poor numbers, the researchers took advantage of CMV's affinity for glioblastoma, with the viral proteins being expressed in roughly 90 per cent of these tumours.

They used the CMV as a proxy for glioblastoma, while targeting the virus with pp65-specific dendritic cells to spotlight the tumour for the immune system.

Previous work had shown that TMZ generates profound lymphopenia or the loss of immune cells, which offers a unique opportunity to retrain the immune system, Batich explained.

The researchers administered dose-intensified temozolomide (TMZ) as a strategy to further enhance the immune response.

"The dose-intensified temozolomide induces a strong state of lymphopenia. With that comes an opportune moment to introduce an antigen-specific vaccine, which redirects the immune system to put all hands on deck and fight that target," Batich said.