The medical benefits of cannabis: still awaiting proof

Stephanie Keeling is a rheumatologist and professor of medicine at the University of Alberta. She is currently participating in the Certificate in Health Impact program at the Dalla Lana School of Public Health at the University of Toronto.

Four years after the legalization of cannabis, the federal government’s clinical trials database at Health Canada does not show strong active research to assess its purported medicinal properties. This shortcoming frustrates many researchers, who say cannabis growers, processors and sellers in Canada have little incentive to fund rigorous pharmaceutical testing of their claims.

According to the researchers, the industry is content rather to sell its products in accordance with the less stringent requirements that govern the recreational consumption market.

“Cannabis producers show no willingness to support medical access,” according to Mary-Ann Fitzcharles, associate professor of medicine at McGill University and a leading researcher in the field of pain. She adds that the first hopes of a partnership between industry and researchers to carry out the necessary studies have faded.

This lack of data makes it difficult for patients trying to relieve their ailments — or their doctors — to verify the accuracy of the claims made by cannabis companies and some patient advocacy groups. The studies cited by these companies to support their claims are not clinical trials, they are mainly patient surveys and observational studies often conducted by the companies themselves, which can lead to bias. considerable. Approximately 400,000 Canadians currently have an authorization to use cannabis for medical purposes issued by their doctor, and it is believed that many more people use it in the same way.

But there is no data yet on its effectiveness or potential harm.

The scientific community attributes this failure to various reasons. The legalization of cannabis in Canada in 2018 opened the door to collaborations between researchers and industry to finally test its medicinal properties using the gold standard: clinical trials. However, cannabis is classified as a drug under the Food and Drugs Act, so it must adhere to Health Canada’s Good Manufacturing Practices to consistently meet quality standards. For companies in the sector, this research process is more complicated and more expensive than the less difficult process of obtaining authorization to market cannabis for recreational purposes. Even if a researcher wanted to legally buy cannabis from a local supplier and test it, they would have to go back to the starting point and do many more studies to successfully file a clinical trial application with Health Canada for this form of cannabis.

Researchers also point out that studies can be hampered by the complexity of the ingredients that make up cannabis products, including widely varying amounts of tetrahydrocannabinol (THC), the chemical that gets you high.

But they also fault Health Canada for failing to proactively streamline the cannabis clinical trial process while ensuring quality standards. Last year, more than 200 clinicians and scientists wrote an open letter to Health Canada asking for a review of the current regulatory process.

So far, things have hardly moved on this front. A few tweaks have made it easier for a handful of researchers to obtain research licenses and permission to begin conducting cannabis studies in certain situations, such as when there is adequate safety data for humans.

This, however, is not enough to prioritize the cannabis studies that researchers say they need, as most cannabis product candidates have yet to undergo extensive preclinical and safety studies.

« A separate pathway for prescription cannabis products is not being considered at this time, » said Tammy Jarbeau, senior media relations advisor for Health Canada. A mandatory review of the Cannabis Act, which was due to begin in October 2021, is expected shortly, according to Ms. Jarbeau. It is unclear whether this review will focus on ways to improve Health Canada’s regulations governing cannabis studies.

The government’s slow response is discouraging, said James MacKillop, professor of psychiatry and behavioral neuroscience and director of the Michael G. DeGroote Center for Medicinal Cannabis Research at McMaster University. “I wish we had allowed the evaluation of the therapeutic virtues of products legally sold to Canadians,” says MacKillop. “Why not create a pathway to assess whether the products that Canadians consume are effective or not? »

Cannabis companies share frustration with the way studies are conducted in Canada. Some of them, such as Canopy Growth Corporation, located in Ontario, claim to be doing trials in other countries, including, in recent years, in the United States, where federal laws such as the Farm Bill allow academic institutions to more easily conduct studies on the health effects of cannabis.

But the industry recognizes that the strong financial headwinds in the cannabis sector, which caused some companies to go out of business and others to merge to survive, have diverted attention and resources away from clinical research. , slowing down the accumulation of solid evidence.

“Companies like Canopy need to set their priorities — where to invest their money and where to put their energy,” says Mark Ware, chief medical officer at Canopy Growth Corporation. Like other companies in the industry in Canada, he says, Canopy has focused more on the business side than on medical research. “As we were struggling with these issues, the company went through some reorganizations and redefined its strategies; the idea of ​​pursuing the development of pharmaceuticals was not a priority at that time,” says Mark Ware.

Patients, on the other hand, cannot expect clear answers from advocacy organizations. Cannabis information on the Arthritis Society website is sponsored by companies like Spectrum Therapeutics, a pharmaceutical company owned by Canopy Growth. Spectrum Therapeutics’ website states that it provides « medical cannabis products to improve the lives of patients worldwide. »

The Arthritis Society site devotes several pages to the medical use of cannabis for pain control, featuring information on everything from how to access it to online webinars hosted by doctors — and sponsored by cannabis producers such as Harvest Medicine and Canna Farms.

Siân Bevan, Executive Director of Science at The Arthritis Society, is not insensitive to the lack of evidence. She points out that the Arthritis Society is funding cannabis research to fill that void, but in the meantime, it needs to help the many Canadians who already use cannabis for pain relief. “People want to understand what we know and what we don’t know, and we can provide that platform for people who come to us for information,” says Siân Bevan.

The researchers insist that only evidence from clinical trials can resolve this uncertainty. “It seems to me that we should do everything possible to weigh the pros and cons [de l’utilisation médicale du cannabis] says James MacKillop.