A cancer-killing virus has shown promise in tackling an aggressive type of brain tumour, researchers say.

Certain viruses selectively target and kill cancer cells while leaving healthy cells unharmed.

They have been tested widely against the cancer, called glioblastoma, but delivering these treatments is challenging.

In the new early stage study, researchers from Queen Mary University of London, the Chinese Academy of Sciences and Capital Medical University in Beijing tested the new treatment in eight patients.

This virus enhances the positive signals that encourage the immune system to attack the tumour

They found that it was safe and effective, and complete remission was achieved in one patient.

Glioblastoma is the most common and fatal type of brain cancer, with most patients surviving fewer than 14 months after diagnosis.

Tumour recurrence is common, and existing treatments have limited success.

Professor Yaohe Wang, co-lead author of the study and inventor of the virus being tested, said: “Most existing oncolytic viruses are ineffective at low doses and too toxic at higher doses.

“The key challenge is how to increase efficacy without causing harmful side effects.

“We believe our approach offers a way forward.”

Prof Wang added: “It’s like yin and yang.

“This virus enhances the positive signals that encourage the immune system to attack the tumour, but it could also be paired with treatments that block the tumour’s ability to suppress the immune system.”

The researchers genetically engineered an adenovirus (a type of virus typically associated with common colds) to deliver potent immune-boosting proteins.

The protein can inhibit tumour growth but is very toxic in its natural form.

To overcome this, the team engineered a version that restricts its release from cells, limiting it to the area surrounding the tumour and preventing it from building up to high levels throughout the body.

Next the team plans to progress to phase 2 clinical trials where the effectiveness of the treatment can be more fully assessed in a larger group of patients.

The findings are published in the Nature Communications journal.