Scientists are a step closer to finding an effective treatment for an aggressive and fatal brain tumour, thanks to a low-intensity ultrasound technique.

The ultrasound device implanted in the skull uses tiny bubbles to open the “blood-brain barrier” to deliver drugs to the brain to treat glioblastoma.

The blood-brain barrier is a network of blood vessels and cells that protects the brain from toxins and infection.

But it also makes it hard for chemotherapy drugs to reach brain tumour cells, making diseases like glioblastoma difficult to treat, and injecting drugs directly into the brain can be toxic.

Scientists at Northwestern University in Illinois have, for the first time, been able to quantify the concentrations of chemotherapy drug in the human brain after the device was used to temporarily open the blood-brain barrier.

They were also able to determine how long the barrier remained open after sonication, a process which uses sound waves to agitate particles.

Lead investigator Dr Adam Sonabend, an associate professor of neurological surgery at Northwestern University Feinberg School of Medicine and a Northwestern Medicine neurosurgeon, said: “This is potentially a huge advance for glioblastoma patients.

“There is a critical time window after sonification when the brain is permeable to drugs circulating in the bloodstream.”

Around 3,200 people in the UK are diagnosed with glioblastoma each year.

The average survival time is around 15 months, with fewer than 10% of patients alive five years after diagnosis following standard treatment.

As part of the phase 1 clinical trial, 17 glioblastoma patients had the ultrasound device implanted in the skull.

A few weeks later, they began treatment with common chemotherapy drugs carboplatin and paclitaxel.

In normal circumstances, these medicines do not cross the blood-brain barrier.

But the ultrasound device works by making tiny bubbles vibrate inside the brain’s blood vessels, temporarily making the protective outer layer permeable.

The researchers found that opening the barrier led to a four to six-fold increase in drug concentrations in the human brain.

They also noted that the barrier restoration happens in the first 30 to 60 minutes after sonication.

The treatment was found to be safe and well tolerated and some patients received up to six cycles.

Dr Sonabend said their work, published in the journal Lancet Oncology, “opens the door to investigate novel drug-based treatments for millions of patients who suffer from various brain diseases”.

Martin Ledwick, Cancer Research UK’s head information nurse, said: “One of the challenges in treating brain cancers is that many chemotherapy drugs don’t cross the blood-brain barrier.

“This limits us being able to test them on brain cancers.

“If shown to be effective, trials like this could represent an important step towards opening up more treatment options for patients with this type of cancer.

“However, it is important to acknowledge that these trials are small, and it is still too early to tell whether there will be any improvement in treatment outcomes for patients through this approach.”

Dr David Jenkinson, chief scientific officer at the Brain Tumour Charity, added: “There is a huge and urgent need for new treatment options for those diagnosed with a glioblastoma.

“After initial treatment, these brain tumours almost always grow back and at this point there are very few treatment options available.

“While we are mindful of the toxicity of some treatments, this innovative study could potentially open up the possibility of using existing and new drugs which don’t penetrate into the brain to offer more options to those with glioblastoma.

“Treatments for glioblastoma have not improved significantly in the last 15 years.

“It is therefore vital that we keep looking for kinder treatments specifically designed to cross the blood-brain barrier so that people who have this devastating diagnosis live longer, better lives.

“We look forward to further updates from this trial as it advances as novel treatments could change the lives of people diagnosed with a glioblastoma.”