More research on cannabis-based medicinal products urgently needed
Author: Caroline White
The lack of good quality evidence on the safety and cost effectiveness of cannabis-based products for medicinal use (CBPMs) has proved a major hurdle to prescribing them, finds a review* of progress on access since their reclassification in November last year.
Most of the clinicians interviewed for the NHS England/Improvement review said that products containing THC, one of the active ingredients in cannabis, would not be prescribed in their trusts, primarily because of the lack of knowledge about these products and hard evidence on their long-term safety.
Several referenced the higher risk of mental health issues associated with longer term exposure to THC and the need to adopt a cautious approach.
Health and social care secretary Matt Hancock commissioned the review in March this year to identify any barriers in NHS processes and systems to clinically appropriate prescribing of CBPMs and what might need to be done to overcome them.
The review recommends the establishment of a UK-wide paediatric specialist clinical network to provide specialist clinical expertise to clinicians and to assist in evidence generation, and the development of clear information for patients and patient groups on the prescribing of CBPMs.
It also calls for research into the five priority research areas identified by the draft National Institute for Health and Care Excellence (NICE) clinical guideline on the use of CBPMs, published yesterday.
The NICE draft recommendations, which were fast tracked, are open for public consultation until 5 September 2019.
The guidance considers the use of these CBPMs for people with intractable nausea and vomiting as a result of chemotherapy, chronic pain, spasticity, and severe treatment-resistant epilepsy.
It includes the licensed products Sativex for treating spasticity in people with multiple sclerosis (MS) and nabilone for treating symptoms of nausea and vomiting in people having chemotherapy.
It makes eight separate recommendations for further research across all the indications and products covered in the guidance, reflecting the overall lack of clinical and cost-effectiveness evidence for these products.
The committee were unable to make a recommendation about the use of cannabis-based medicines for severe treatment-resistant epilepsy because there was a lack of clear evidence that these treatments provide any benefits.
The draft guidance recommends nabilone as an add-on treatment for adults with chemotherapy-induced nausea and vomiting which hasn’t responded to conventional licensed drugs.
The draft guidance doesn’t recommend Sativex for treating spasticity in people with MS because it isn’t cost-effective at its current list price. Other CBPMs shouldn’t be offered to treat spasticity unless as part of a clinical trial.
The draft guidance also says that, other than cannabidiol (CBD, a pure, plant-derived cannabinoid) used on its own in the context of a clinical trial, no CBPMs should be used for treating chronic pain. Again, this is because the benefits they offer are very small compared with their high costs.
Paul Chrisp, director of the Centre for Guidelines at NICE, said: “We recognise that some people will be disappointed that we have not been able to recommend the wider use of cannabis-based medicinal products.
“However, we were concerned when we began developing this guidance that a robust evidence base for these mostly unlicensed products was probably lacking. Having now considered all the available evidence it’s therefore not surprising that the committee has not been able to make many positive recommendations about their use.”
He added that NICE welcomed the recent suggestion from the House of Commons Health and Social Care Committee that companies should be encouraged to undertake or enable research into their medicinal cannabis products.
Dr Keith Ridge, chief pharmaceutical officer at NHS England said: “Without sufficient evidence to help them balance potential benefits against potential harms when they are deciding whether to prescribe medicinal cannabis to children with very severe epilepsy, it is clear clinicians are very reluctant to [do so].
“We heard loud and clear the concerns and frustration the children’s families are feeling, but these recommendations aim to help us develop the evidence base to understand how safe these products are, and ensure education and expert advice is available to support clinicians across the UK.”
Final NICE guidance is expected in November 2019. In the interim, the British Paediatric Neurology Association, the Royal College of Physicians, and The Association of British Neurologists have produced guidance around prescribing of CBPMs.
The national medical director and chief pharmaceutical officer for England will also write to doctors and pharmacists reminding them of General Medical Council guidance on the prescribing and use of unlicensed medicines – and clarifying the procedure for prescribing and supplying CBPMs.
*Barriers to accessing cannabis-based products for medicinal use on NHS prescription Findings and Recommendations. NHS England and NHS Improvement, August 2019