“The recent early-stage findings were really promising and we now look forward to understanding whether adding Sativex to chemotherapy could offer life extension and improved quality of life, which would be a major step forward in our ability to treat this devastating disease,” added Jenkinson.
Short said that the initial study suggested that the drug could give some people some extra life. More participants who had Sativex were still alive a year later than those who had a placebo.
Sativex contains equal amounts of two cannabinoids: the psychoactive substance Delta-9-tetrahydrocannabinol (THC), which gives users a “high”, and cannabidiol (CBD), which can help reduce pain, inflammation and anxiety without inducing any psychoactive effects.
“We think that Sativex may kill glioblastoma tumour cells and that it may be particularly effective when given with temozolomide chemotherapy, so it may enhance the effects of chemotherapy treatment in stopping these tumours growing, allowing patients to live longer, said Susan Short, a professor of clinical oncology and neuro-oncology at Leeds University, who is the principal investigator of the study. “That is what we want to test in the study,” she said.
About 2,200 people in England are diagnosed every year with the condition, making it the commonest form of brain cancer.
The Brain Tumour Charity plans to push ahead with the trial but stressed that doing so depended on the results of an appeal to help cover the £450,000 costs involved. It has suspended its usual programme of research grants after losing 25% of its income during the Covid-19 pandemic.
“We hope this trial could pave the way for a long-awaited new lifeline that could help offer glioblastoma patients precious extra months to live and make memories with their loved ones,” said Dr David Jenkinson, the Brain Tumour Charity’s interim chief executive.
Sativex is already given to patients with multiple sclerosis whose condition has not improved despite treatment, in order to reduce their spasticity. It is one of three cannabis-based medicines currently in use in the NHS.
Glioblastoma is one of the deadliest forms of brain tumor and even with treatment the median survival after diagnosis is 15 months, according to the Glioblastoma Foundation. Research into new therapies over the last 15 years has increased survival only by two or three months, said Dr. Martin Rutkowski, a neurosurgeon specializing in brain tumors at Medical College of Georgia at AU and one of the researchers.
Rutkowski likens it to a protective barrier around the tumor.
“I am skeptical when it comes to CBD treating depression or anxiety or financial distress or marriage problems,” he said. “That’s probably not all true. But now that we have some basic science that supports this (therapy) I think it is really exciting.”
Several pre-clinical laboratory studies have suggested that cannabinoids THC and CBD may reduce brain tumour cell growth and could disrupt the blood supply to tumours – but to date, clinical evidence that they could treat brain tumours has been limited.
The new three-year phase II trial (ARISTOCRAT), funded by The Brain Tumour Charity and co-ordinated by the Cancer Research UK Clinical Trials Unit at the University of Birmingham, is due to begin recruiting more than 230 patients across all UK nations in early 2022, subject to sufficient funds being raised.
Tackling aggressive brain cancer
Dr David Jenkinson, Interim CEO at The Brain Tumour Charity, which is funding the trial, said: “We hope this trial could pave the way for a long-awaited new lifeline that could help offer glioblastoma patients precious extra months to live and make memories with their loved ones.
“Glioblastoma brain tumours have been shown to have receptors to cannabinoids on their cell surfaces, and laboratory studies on glioblastoma cells have shown these drugs may slow tumour growth and work particularly well when used with temozolomide.
‘Life beyond a glioblastoma diagnosis’
Sativex, manufactured by GW Pharma, is an oromucosal spray containing 1:1 THC (Delta-9-tetrahydrocannabinol) and CBD (cannabidiol), with the active ingredients being absorbed in the lining of the mouth, either under the tongue or inside the cheek.