1.9 million euros for research into neuropathic pain

The Dutch government is supporting research into the use of medicinal cannabis in the treatment of neuropathic pain with € 1.9 million. The grant has been awarded to a joint project of the Centre for Human Drug Research (CHDR), a Dutch independent institute that specializes in clinical drug research, and the Leiden University Medical Center (LUMC). Neurologist Geert Jan Groeneveld (CSO / CMO at CHDR and professor of Clinical Neuropharmacology at the LUMC) and Albert Dahan (professor of Anesthesiology at the LUMC) will conduct the research.

The research intends to lead to a specific recommendation of an optimal delta-9-tetrahydrocannabinol (THC) –  cannabidiol (CBD) dosage for the treatment of neuropathic pain in a particular subgroup of patients. In addition, it contributes to evidence for the effectiveness of medicinal cannabis. Bedrocan’s raw materials will be used for the production of the research material.

“We are going to isolate the THC and CBD from Bedrocan cannabis and administer them in tablet form in different proportions. We will then look at the influence of CBD on the effects of THC , and investigate which THC-CBD combination is best for the treatment of neuropathic pain”, said Groeneveld.  The Dutch company Echo Pharmaceuticals from Leiden will produce the tablets for the research.

Healthy subjects

The study consists of two parts. In the first part, healthy subjects will be administered the tablets with different THC and CBD ratios. The first part of the research will show whether the adverse effects of THC, such as getting high or feeling anxious, can be reduced by administering CBD simultaneously. According to Groeneveld, the scientific literature has so far provided conflicting results about this: “To be honest, I do not expect much from CBD alone as a treatment for neuropathic pain. From a pharmacological point of view, it is likely that THC affects pain, but this is less the case for CBD. CBD could have an effect on inflammation, but there is no reason  to use CBD as a treatment for inflammatory pain. We already have Ibuprofen for that. It will only become interesting if the adverse effects of THC, such as feelings of anxiety, can be alleviated by administering CBD at the same time. “

Patients with neuropathic pain conditions

The effects on pain in patients will not be investigated until the second part of the study, after the results of the first study are known. This will provide information on which THC:CBD ratio works best. The second part of the study will take place among a diverse group of 200 patients with different neuropathic pain conditions. Groeneveld: “We are going to phenotype this group very well in advance. This means that we want to know exactly how the neuropathic pain manifests itself specifically in this group. Do patients have demonstrable nerve damage, do they have a personality disorder, are they depressed, or do they have sleep disorders? All these are variables that we are going to map.”

Subsequently, the participants in a crossover study will receive placebo for five weeks, and after a wash-out period, they will receive five weeks of cannabinoid treatment or vice versa. Pain will be measured in each treatment period. Groeneveld: “In patients with clear pain relief, we want to further investigate whether there is a correlation between their variables, such as sleeping problems, anxiety or peripheral nerve damage, and the response to treatment with THC.”

The first part of the study will start in the spring of 2021, and Groeneveld expects the first results in the summer. The second part of the study with the pain patients will start in the autumn and will last at least two years.