Drugs Research & Development 2003;4(5):306-9.
Cannabis-based medicines--GW pharmaceuticals:
high CBD, high THC, medicinal cannabis--GW pharmaceuticals,
THC:CBD.
[No authors listed]
GW
Pharmaceuticals is undertaking a major research programme
in the UK to develop and market distinct cannabis-based
prescription medicines [THC:CBD, High THC, High CBD]
in a range of medical conditions. The cannabis for this
programme is grown in a secret location in the UK. It
is expected that the product will be marketed in the
US in late 2003.
GW's
cannabis-based products include selected phytocannabinoids
from cannabis plants, including D9 tetrahydrocannabinol
(THC) and cannabidiol (CBD). The company is investigating
their use in three delivery systems, including sublingual
spray, sublingual tablet and inhaled (but not smoked)
dosage forms. The technology is protected by patent
applications. Four different formulations are currently
being investigated, including High THC, THC:CBD (narrow
ratio), THC:CBD (broad ratio) and High CBD.
GW
is also developing a specialist security technology
that will be incorporated in all its drug delivery systems.
This technology allows for the recording and remote
monitoring of patient usage to prevent any potential
abuse of its cannabis-based medicines. GW plans to enter
into agreements with other companies following phase
III development, to secure the best commercialisation
terms for its cannabis-based medicines. In June 2003,
GW announced that exclusive commercialisation rights
for the drug in the UK had been licensed to Bayer AG.
The drug will be marketed under the Sativex brand name.
This agreement also provides Bayer with an option to
expand their license to include the European Union and
certain world markets.
GW
was granted a clinical trial exemption certificate by
the Medicines Control Agency to conduct clinical studies
with cannabis-based medicines in the UK. The exemption
includes investigations in the relief of pain of neurological
origin and defects of neurological function in the following
indications: multiple sclerosis (MS), spinal cord injury,
peripheral nerve injury, central nervous system damage,
neuroinvasive cancer, dystonias, cerebral vascular accident
and spina bifida, as well as for the relief of pain
and inflammation in rheumatoid arthritis and also pain
relief in brachial plexus injury.
The
UK Government stated that it would be willing to amend
the Misuse of Drugs Act 1971 to permit the introduction
of a cannabis-based medicine.
GW
stated in its 2002 Annual Report that it was currently
conducting five phase III trials of its cannabis derivatives,
including a double-blind, placebo-controlled trial with
a sublingual spray containing High THC in more than
100 patients with cancer pain in the UK. Also included
is a phase III trial of THC:CBD (narrow ratio) being
conducted in patients with severe pain due to brachial
plexus injury, as are two more phase III trials of THC:CBD
(narrow ratio) targeting spasticity and bladder dysfunction
in multiple sclerosis patients. Another phase III trial
of THC:CBD (narrow ratio) in patients with spinal cord
injury is also being conducted. Results from the trials
are expected during 2003.
Three
additional trials are also in the early stages of planning.
These trials include a phase I trial of THC:CBD (broad
ratio) in patients with inflammatory bowel disease,
a phase I trial of High CBD in patients with psychotic
disorders such as schizophrenia, and a preclinical trial
of High CBD in various CNS disorders (including epilepsy,
stroke and head injury).
GW
Pharmaceuticals submitted an application for approval
of cannabis-based medicines to UK regulatory authorities
in March 2003. Originally GW hoped to market cannabis-based
prescription medicines by 2004, but is now planning
for a launch in the UK towards the end of 2003. Several
trials for GW's cannabis derivatives have also been
completed, including four randomised, double-blind,
placebo-controlled phase III clinical trials conducted
in the UK. The trials were initiated by GW in April
2002, to investigate the use of a sublingual spray containing
THC:CBD (narrow ratio) in the following medical conditions:
pain in spinal cord injury, pain and sleep in MS and
spinal cord injury, neuropathic pain in MS and general
neuropathic pain (presented as allodynia).
Results
from these trials show that THC:CBD (narrow ratio) caused
statistically significant reductions in neuropathic
pain in patients with MS and other conditions. In addition,
improvements in other MS symptoms were observed as well.
Phase II studies of THC:CBD (narrow ratio) have also
been completed in patients with MS, spinal cord injury,
neuropathic pain and a small number of patients with
peripheral neuropathy secondary to diabetes mellitus
or AIDS. A phase II trial of THC:CBD (broad ratio) has
also been completed in a small number of patients with
rheumatoid arthritis, as has a trial of High CBD in
patients with neurogenic symptoms. A phase II trial
has also been evaluated with High THC in small numbers
of patients for the treatment of perioperative pain.
The phase II trials provided positive results and confirmed
an excellent safety profile for cannabis-based medicines.
GW
Pharmaceuticals received an IND approval to commence
phase II clinical trials in Canada in patients with
chronic pain, multiple sclerosis and spinal cord injury
in 2002. Following meetings with the US FDA, Drug Enforcement
Agency (DEA), the Office for National Drug Control Policy,
and National Institute for Drug Abuse, GW was granted
an import license from the DEA and has imported its
first cannabis extracts into the US. Preclinical research
with these extracts in the US is ongoing.
PMID:
12952500 [PubMed - in process]
Abstract
Reproduced from Medline.