Inhaled CBD has the potential to shrink aggressive brain tumour glioblastoma by fighting the microenvironment that enables it to grow, a new study has found.
Researchers in the US said experiments carried out on mice, using modified glioblastoma cells taken from humans, showed encouraging results and justified further analysis.
In the first study of its kind, tumours were established over eight days, with the mice then given daily doses of CBD or a placebo over seven days.
Dr Babak Baban, an immunologist and associate dean for research at Augusta University, described the reduction in size of the tumour in the mice inhaling CBD as “significant”.
As with other tumours, glioblastomas develop an ecosystem that protect them from the immune system and enable them to take hold and grow.
The study, reported in the journal Cannabis and Cannabinoid Research, found CBD can alter that ecosystem and block “immune checkpoints” that the tumour uses to assist its growth.
Researchers realised the cannabis was taking effect through the sudden presence of T cells from the immune system, which Dr Baban said are “extremely important in fighting tumours”, but which are actively blocked by glioblastoma.
“We are excited that the tumour shrinks [in those taking the CBD],” Dr Baban said, noting that the positive results occurred without any other treatment working in tandem with CBD.
Another of the study’s authors, Dr Martin Rutkowski, a neurosurgeon at the Medical College of Georgia, said research is desperately needed.
“It’s probably one of the most aggressive cancers, period,” he said. “We are in desperate need of research and more treatments. What we have now is not working very well.”
Attention will now turn to assessing how long the positive results last and analysing whether it can prevent the tumour from returning, a major problem with glioblastoma.
Dr Baban said he also hopes to conduct an early stage clinical trial in a small number of patients.
Meanwhile, a three-year phase II trial assessing the impact of Sativex on glioblastoma is set to be carried out by the University of Leeds in the UK.
Starting in March, the study has been funded through public donations totalling £400,000 (A$760,000) to the Brain Tumour Charity.
“We know there has been significant interest among patients and researchers alike for some time about the potential activity of cannabinoids in treating glioblastomas,” the charity’s interim chief executive David Jenkinson said.
“The recent early-stage findings were really promising and we now look forward to understanding whether adding Sativex to chemotherapy could help offer life-extension and improved quality of life, which would be a major step forward in our ability to treat this devastating disease.”