“It tastes like strawberry,” this is how marijuana derivatives are being tested against childhood epilepsy
- An active ingredient extracted from cannabis reduces the number of seizures in children who do not respond to other drugs.
In a secret location in England, a massive greenhouse houses tens of thousands of marijuana plants cultivated with the utmost care. Their seeds have been selected over years to achieve the perfect varieties. Harvesting takes place every three weeks. After crushing and heating the seeds, experts in white coats extract a sticky, dark, caramel-like concentrate from the plants. Once processed, bottled, and labeled, the final product ends up in several European countries, including Spain.
The greenhouse in question is the largest legal marijuana plantation in the UK. It is owned by the British company GW Pharmaceuticals, the leading company in the development of cannabis compounds to treat various diseases. Founded 17 years ago, the company has perfected its cultivation methods to ensure that each and every plant has the same concentrations of the biochemicals of interest—a standardization essential for transforming them into a drug.
For the past few months, 25 Spanish children with a type of epilepsy that doesn't respond well to conventional medications have been testing one of these chemical compounds as part of one of the most promising clinical trials of marijuana-related substances. The trial remains open to new patients in several countries until it reaches 150 participants. All of them have Dravet syndrome, a rare form of epilepsy that usually appears around six months of age, causes seizures that are longer than normal, and leads to recurring brain damage that can be fatal in the most extreme cases.
These are patients with “many needs,” explains Rocío Sánchez-Carpintero, from the Clínica Universidad de Navarra and coordinator of the clinical trial in Spain. “It’s not just due to epileptic seizures, but also to cognitive developmental delays, learning difficulties, and motor problems,” emphasizes this neuropediatrician, who directs the only hospital unit specializing in this syndrome in Spain. Eleven of her Dravet patients are participating in the Phase III clinical trial, which measures the efficacy of a drug and is usually the last phase before approval is sought if successful.
Dravet syndrome is also an incurable disease. “In general, most cases of epilepsy are controlled with existing medications,” explains Antonio Gil-Nagel, a neurologist at Ruber International Hospital. “With Dravet, the 90% of patients does not respond to those same drugs”, he points out.
Molecular structure of THC and CBD
Syrup
The compound in question is CBD, or cannabidiol, a substance without psychoactive effects that, along with THC, is one of the most explored for its therapeutic uses. Previous trials have shown that CBD reduces the number of seizures by half in roughly half of the patients who try it. “There have even been 161,000 patients who didn't experience a single seizure,” explained Colin Stott, head of R&D at GW Pharmaceuticals, last week during a Summer Course organized by the Complutense University of Madrid. These trials are also measuring other indicators of CBD's activity, such as improvements in memory, concentration, and language in children, where there have been some surprising cases, such as that of a boy who didn't speak before the trial and whose speech returned “explosive” after participating, Stott said. The company collaborates with 29 universities in several countries, and Spain, he said, is one of the “major players in cannabinoid compound research.”.
As in other cases, it was the parents of children with these types of epilepsy who began pressuring authorities to launch clinical trials with CBD, for which only clinically unproven evidence existed. In their desperation because no medication seems to stop or alleviate the seizures, some parents resort to using homemade cannabis preparations, such as oil. “We never recommend their use and tell them that we can’t help them that way, although we do ask them to continue coming to the clinic and keeping us informed of their child’s progress,” explains Gil-Nagel.
The British company has selected plants with high CBD and very low THC content. It then purifies an extract containing only CBD and turns it into a syrup flavored with strawberry. The results of the clinical trial may be available early next year. The fact that Dravet syndrome is classified as an orphan disease may expedite the approval process for the drug, called Epidiolex. CBD is showing even better results in clinical trials against Lennox-Gastaut syndrome, another form of childhood epilepsy resistant to conventional drugs. “This substance is showing greater effectiveness, in up to 601% of patients, and this is important because it is a refractory epilepsy in which children can have up to 100 seizures a day,” explains Julián Lara, a pediatrician at Puerta de Hierro Hospital in Madrid, who is also involved in the trials.
Later, applications could emerge for diseases affecting millions of people. “Whenever people think of marijuana, they think of getting high,” Stott lamented to his audience, “but there are 99 other compounds” that don't produce a high and that may have medical applications, he emphasized. For now, his company is investigating five of them. One of the most striking applications is in schizophrenia. Until now, marijuana was thought to be harmful to schizophrenics, since THC can exacerbate psychosis, but trials are showing that CBD has the opposite effect and appears to reduce attacks. The company is also exploring applications for diabetes and glioma, among other ailments.
Fountain: elpais.com
http://elpais.com/elpais/2015/07/29/ciencia/1438183954_224346.html