GW Pharmaceuticals is undertaking a major research programme in the UK to develop a range of distinct cannabis-based medicines. This is a pharmaceutical development programme which involves pre-clinical and clinical research according to standards laid down by the regulatory authorities. The aim of this research is to obtain approval from the regulatory authorities around the world to market distinct cannabis-based prescription medicines for a range of medical conditions.

Cannabis for use in the research programme is grown in a secret location in the UK. To find our more about this cultivation programme, click here. Whole plant extracts are taken from different cannabis plant varieties and used to develop medicines for a range of medical conditions. These extracts are incorporated into sophisticated drug delivery technologies and then tested in clinical trials.

Drug Delivery Technologies

Cannabis can be taken by a variety of routes of administration. Smoking is the most common means of taking herbal cannabis and is, according to many patients, a very effective method of drug delivery. It is reported, in some instances, that relief is obtained after the second puff of a cannabis cigarette. This means that biologically significant amounts are reaching the systemic circulation within 30 - 60 seconds after the start of inhalation. However, smoking delivers carcinogenic tars and particulates into the bronchial tree, and is not seen as an appropriate method of drug delivery for a prescription product.

GW's cannabis-based medicines are being administered using sub-lingual and inhaled (but not smoked) dosage forms. There may, however, be some trials in which a smoked form may be used for comparative purposes.

Pre-clinical Trials

GW is collaborating with universities and other researchers to conduct an extensive pre-clinical research programme. Such research is intended to provide insight into mechanisms through which cannabis provides medical benefit and also to discover new therapeutic uses for cannabis. The pre-clinical programme is already underway and includes receptor interaction studies and general pharmacology. 

Clinical Trials

Phase I work in volunteers has already commenced. These trials are being followed rapidly by Phase II trials using the n of 1 design. The first set of trials has already received Ethics Committee approval. In n of 1 trials, each patient is the complete study acting as his or her own control. This methodology has also been suggested by the recent Institute of Medicine Report as one which may prove to be a useful tool in the investigation of the therapeutic benefits of cannabis-based medicine extracts

Since each patient is a study, this approach can be used to accommodate many patients suffering from a variety of conditions who live in different geographical areas. It is also a useful means by which we can try to bring patients currently using herbal cannabis into the trials. We expect early trials to encompass patients suffering from conditions including severe neuropathic pain, neuroinvasive cancer, trigeminal neuralgia, spinal cord injury, pain and spasm of multiple sclerosis and many others. The clinical programme will expand to include group design Phase II studies.

Phase III pivotal regulatory controlled trials will commence in 2000. During these pivotal trials, n of 1 trials will continue to support evidence on other conditions.

All patients who wish to continue treatment with GW's medicines following conclusion of the acute phase of their clinical trial will have the option to enter into a long term safety study.

For information about participation in clinical trials, click here