Interim results from a clinical trial into glioblastoma - a deadly form of brain cancer - are encouraging, the Cure Brain Cancer Foundation says.

Australia's peak organisation for brain cancer research has been buoyed by a "promising" vaccine that could add years to the lives of people with an aggressive form of brain cancer.

The treatment for people with glioblastoma works by using the immune cells of patients to target their tumour.

Early findings from an 11-year international clinical trial involving more than 300 sufferers worldwide, released on Wednesday, show those given the vaccine are living longer than expected.

The international researchers says the results hint at a "major breakthrough" in the treatment of glioblastoma, which is the most common and deadly form of brain cancer.

Cure Brain Cancer Foundation chief executive Michelle Stewart says once the results are confirmed they will begin work to get access to the treatment for people living with GBM in Australia.

However, Ms Stewart is urging caution until the final data is released because the results "may get better or worse".

The standard treatment for glioblastoma is surgery followed by radiotherapy and chemotherapy.

The current median survival for GBM in Australia is just 15 months.

Of the 331 patients with glioblastoma who took part in the trial, 232 were injected regularly with immunotherapy vaccine DCVax in addition to standard care, while the remaining group were given a placebo.

Published in the Journal of Translational Medicine, released on Wednesday, the interim results showed patients involved in the trial survived for more than 23 months on average after surgery.

Almost one-third lived for an average of 40.5 months, the authors said.

"These results, if confirmed when the final analysis is complete, are very encouraging," Ms Stewart said.

"This therapy could have the potential to change the outlook for many patients with GBM, who currently have very few options."