IACM-Bulletin of December 12, 2004

UK — Regulators demand further studies to decide on application by GW Pharmaceuticals

An oral cannabis extract produced by GW Pharmaceuticals and investigated in clinical studies, called Sativex, did not get approval for sale by British regulators, the firm said on 3 December. The Committee on Safety of Medicines (CSM), an advisory body to the Medicines and Healthcare products Regulatory Agency (MHRA), noted that the extract did not meet one of three criteria of drug approval.

The CSM acknowledged that the cannabis extract, that is sprayed into the mouth, met the required criteria for quality and safety but not for efficacy. It noted that positive effects were seen on spasticity of patients with multiple sclerosis (MS) in clinical data, but that the clinical relevance of these effects were uncertain. The CSM asked for a further confirmatory study which, if sufficiently positive, would enable grant of a product licence.

Scientists expressed surprise at the outcome. "I am very disappointed that the CSM has not followed my recommendation that the data fully supports the approval of Sativex," said Professor Mike Barnes, the president of the World Federation of NeuroRehabilitation. The British MS Society said the news was "extremely disappointing".

GW Pharmaceuticals already has a trial under way which it intends to model to the regulator's requirements but it will not be completed by the end of next year at the earliest. The firm also intends to appeal the decision to the Medicines Commission, a separate body. This will take six months. It will also try to get approval from the Home Office to sell its extract unlicensed.

(Sources: Press Release by GW Pharmaceuticals of 3 December 2004, Guardian Unlimited of 4 December 2004)

Canada — Study on safety of medical cannabis

A study of safety issues surrounding the medical use of cannabis has just begun. Known as the COMPASS study (Cannabis for the management of pain: assessment of safety study), the research initiative will follow 1400 chronic pain patients, 350 of whom use cannabis as part of their pain management strategy, for a one-year period. Seven pain clinics across Canada are now enrolling patients for this study.

"Patients in COMPASS will typically have pain resulting from spinal cord injuries, multiple sclerosis, arthritis or other kinds of hard-to-treat neuropathic or muscle pain," explains Dr. Mark Ware, principal investigator and pain physician at the McGill University Health Centre (MUHC) Pain Centre in Montreal. "We'll be looking at a range of safety issues, including adverse events, kidney, liver, heart and lung function and hormone levels," adds Dr. Jean-Paul Collet, also a principal investigator and Professor of Epidemiology at McGill University. "Patients will also do tests at the start and end of the study, to help determine whether medical use of cannabis affects cognitive function."

The cannabis to be used in the COMPASS study is produced by Prairie Plant Systems under contract to Health Canada. The strain used in this study contains about 12 percent THC. Government-supplied cannabis will be sent to pharmacies and dispensed to patients there.

Patients wishing to participate in the COMPASS study and others who look for further information may visit the COMPASS website at www.gereq.net/compass.

(Sources: EurekAlert of 8 December 2004, www.gereq.net/compass)

USA — Medical marijuana case before Supreme Court

The principle of states' rights faced a stiff challenge at an US Supreme Court hearing on 29 November, as the justices tried to decide whether federal drug laws should be superior to a California state law permitting the medical use of cannabis.

Justices expressed reservations about allowing medical marijuana for patients whose doctors have recommended it and appeared sympathetic to the federal government's argument that it has the power to prosecute or take other action against patients who use cannabis. The justices are deciding whether a federal law outlawing marijuana applies to two seriously ill California women. California is one of 10 states allowing medical use of cannabis.

The Bush administration appealed to the Supreme Court after a federal appeals court in California ruled that marijuana used for medical purposes was different from drug trafficking. The appeals court said states could adopt medical marijuana laws as long as the marijuana was not sold, transported across state lines or used for non-medicinal purposes. The lawsuit was brought in 2002 by Angel Raich, who has an inoperable brain tumour and other medical problems, and Diane Monson, who suffers from severe back pain. Their doctors recommended marijuana for their pain.

Justice Stephen Breyer said the two women could have gone to U.S. regulators and asked them to allow the use of medical marijuana. If denied, they then could have sued. "That seems to me the obvious way to get what they want," Breyer said. A ruling in the case is due by the end of June 2005.

(Sources: Financial Times of 29 November 2004, Reuters of 29 November 2004, New York Times of 30 November 2004)

News in brief

Science — Psychosis in young people

Researchers of the University of Maastricht in the Netherlands investigated the effect of cannabis use on the development of psychosis in 2473 young people aged 14 to 24 years. Assessment of substance use, predisposition for psychosis, and psychotic symptoms was performed at the start of the study and at follow up four years later. After adjustment for possible influencing factors cannabis use at the start of the study moderately increased the incidence of psychotic symptoms at follow up (adjusted odds ratio 1.7, 95% confidence interval 1.1 to 2.5). The effect of cannabis use was much stronger in participants with a predisposition for psychosis. (Source: Henquet C, et al. BMJ 2004 Dec 1; [Electronic publication ahead of print])

Science — Effects of THC and CBD on memory

The effects of cannabis extracts rich in THC and rich in CBD on working and short-term memory were investigated in rats. The cannabis extract rich in THC impaired both working and short-term memory while the CBD rich extract had no effect. CBD dose dependently antagonized the effects of THC on memory. (Source: Fadda P, et al. Neuropharmacology 2004;47(8):1170-9)