Promising vaccine

Wellington neurosurgeon Martin Hunn successfully tests a new vaccine for aggressive brain cancer on mice.

WELLINGTON neurosurgeon Martin Hunn has successfully tested a new vaccine for aggressive brain cancer on mice.

It stimulates the immune system to attack tumours and could help develop a new treatment for people with glioblastoma multiforme (GBM). The chances of surviving this cancer are slim, as tumours become rapidly resistant to treatment such as surgery, radiotherapy and chemotherapy.

There are four cases per 100,000 New Zealanders and, on average, people die within 15 months of the cancer being diagnosed.

Results, published in the journal Clinical Cancer Research, showed the vaccine, containing tumour cells and an immuneboosting agent derived from marine sponges, was strong enough to kill glioma tumours in mice.

‘‘It’s a vital step and we learned a huge amount about how vaccines work and how the immune system responds,’’ Mr Hunn said.

Early indications showed humans had the immune system ‘‘machinery’’ needed for this immunotherapy to work. Immunotherapy treats disease using the body’s own defence system.

Mr Hunn and colleagues

at Wellington Hospital and the Malaghan Institute recently finished the first phase of a GBM vaccine trial on people, the results of which will be released next year.

Vaccines used in these types of trials are typically created from the patient’s tumour tissue. Dendritic cells that spark the attack against the tumour are needed, but if someone is too sick it can be difficult to isolate enough of these cells from the blood.

After turning away people too sick to take part in the trial, Mr Hunn and Associate Professor Ian Hermans went back to the laboratory to see if they could create a vaccine without dendritic cells.

The vaccine was tested on mice and in some instances tumours disappeared. While the human trial was not a ‘‘game-changer’’, it highlighted the need to switch off a tumour’s ability to suppress the immune system, Mr Hunn said.

‘‘It’s a huge problem. As the tumour evolves it develops all sorts of mechanisms to protect itself from the immune system.

‘‘We not only have to have a strong vaccine, but we need to be able to shut off some of these immuno-suppressant mechanisms.’’ More clinical trials in people are planned, potentially using a similar vaccine to that used in mice.

Photo: KEVIN STENT/FAIRFAX NZ Positive signs: Wellington neurosurgeon Martin Hunn has tested a new vaccine for aggressive brain cancer on mice, with promising results. He is pictured in front of an enlarged image of an immune cell.

Rewarded: Prime Minister’s Science Prize winners and Massey Riddet Institute cofounders Professor Paul Moughan and Professor Harjinder Singh.

Gone: MRI scans of a mouse that received the trial vaccine show that the brain tumour, the white dot in the scan at left, on day 20, is no longer there by day 67.