In a recent blog we interviewed Dr Wai Liu, a Senior Research Fellow at St George’s, University of London, who has been investigating drugs known as cannabinoids and their potential anticancer properties.

The cannabis plant is a notable source of at least 144 naturally occurring cannabinoids. Two of the best understood cannabinoids are Δ(9)-tetrahydrocannabinol (THC) and cannabidol (CBD). Essentially, THC is the primary constituent of cannabis responsible for the ‘high’ that people experience whereas CBD is not intoxicating in normal doses, although it is thought CBD might have therapeutic effects.

Most cannabis-based medicinal products will contain at least some CBD, with many also having varying degrees of THC.

Six months ago, on 1^st November 2018 cannabis-based medicinal products were re-categorised under UK law, allowing them to be prescribed, albeit only by a few specialist doctors working within very tight regulations. The principle of this change was to shift the judgment about cannabis-products from the Home Office to expert clinicians.

This adjustment has begun to take effect, with the Department of Health & Social Care (DHSC) increasingly involved in managing policy around access to cannabis-based products. This would seem to signify that the UK government is increasingly viewing cannabis-based medicinal products as potential medicines that need more scientific research (which is the DHSC’s role) rather than illegal drugs that need policing (which is a function of the Home Office).

Six months after the change in the law, proponents of cannabis-based medicinal products are claiming that not enough prescriptions are being issued. For example, Nabilone (a synthetic cannabinoid for medicinal use, which is used to reduce chemotherapy induced nausea and vomiting) was only prescribed on 44 occasions in January 2019.

The main impediment to prescribing cannabis-based medicinal products was mentioned by Dr Liu, “the lack of full clinical trials confirming activity in patients. Without this ‘badge’, clinicians will rarely prescribe something that has no official clinical value.”

During a recent Parliamentary debate, Philippa Whitford MP, herself a breast cancer surgeon, stated the problem as being “that the way cannabis was treated for 50 years means we have had almost no research and almost no experience.” As cannabis-based medicinal products were ‘illegal’ for so many years (until 1^st November 2018) it has been almost impossible for scientists to conduct research.

In turn, this lack of basic scientific knowledge has meant that the medical community is understandably wary of cannabis-based medicinal products. Guidance from England’s Chief Medical Officer holds that unlicensed cannabis-based medicinal products can only be prescribed by doctors on the General Medical Council Specialist Register. The same guidance also stipulates that doctors should prescribe products only for disorders within their specialty; when there is clear published evidence or UK guidelines to support treatment; when clinical need cannot be met by a licensed medicine; and when established treatment options have been exhausted.

Within the NHS, specialists in the UK will often need authorisation from their medical director and agreement from the patient’s multidisciplinary team, using existing protocols on controlled drugs.

As a result of all of the hurdles that clinicians wishing to prescribe cannabis-based medicinal products must overcome, it is not surprising that few prescriptions are actually being issued.  

The Health Secretary, Matt Hancock MP, has recognised these issues and, in early April 2019, told the House of Commons how he planned to rectify them.

Firstly, NHS England has been tasked with rapidly evaluating its process to remove barriers to clinically-appropriate prescribing. Secondly, training is being developed by Health Education England to support clinicians in their decision whether or not to prescribe. Thirdly, and most importantly, the National Institute for Health Research has been asked to take action to produce the evidence-base around cannabis-based medicinal products. It has responded by pledging dedicated funding and issuing two calls for research proposals.

Additionally, the National Institute for Health and Care Excellence (NICE), has been commissioned to develop guidelines on the prescribing of cannabis-based medicinal products by October 2019.

Cannabis-based medicinal products and brain tumours are both victims of a similar vicious cycle, whereby barriers to research (regulatory or funding) have stymied new innovation, which, in turn, means researchers become less inclined to study the topic. The few pieces of research that have been undertaken into cannabis-based medicinal products are far from conclusive and do seem to indicate that they are very much therapies, rather than cures.

Brain Tumour Research is glad that the Government is facilitating further research into cannabis-based medicinal products, as we believe scientific study will be the key to establishing their effectiveness and, if appropriate, ensuring patients are given access to them under appropriate medical supervision.

There is limited research available on the effect of cannabis-based products to treat brain tumours, although there are related trials taking place, for example two of Brain Tumour Research’s Member Charities (Astro Brain Tumour Fund and Children’s Brain Tumour Research Centre at the University of Nottingham) combined forces in 2017 to launch a study into the clinical effects of cannabidiol (CBD) on child brain tumours.