Clinical trials of formulations of “pure CBD” are much more promising, Dr. Filloux said. Nationwide, 21 sites have expanded Investigational New Drug approval to try Epidiolex , a natural product made by GW Pharmaceuticals that is purified and processed to be essentially 100% CBD, in as many as 25 patients. Similar studies are beginning with a synthetic CBD.
The FDA has also granted orphan drug status to Epidiolex for the treatment of patients with Dravet and Lennox–Gastaut syndromes, and placebo-controlled studies of these rare conditions are under way. Thirty to 50 patients have been on Epidiolex for more than three months, Dr. Filloux reported. Although overall results could be considered a bit discouraging—as with any antiepileptic drug, 50% improvement occurs in 50% of patients—there is an intriguing finding, he noted: At three months, 33% of those with Dravet syndrome self-report that they are seizure free.
Where are we now? Specific marijuana products are probably effective in treating MS, clearly effective in treating pain and nausea, and generating excitement about a possible benefit in some types of childhood epilepsy, Dr. Filloux concluded. Despite the dearth of high-quality studies and difficulties posed by the wide variety of preparations, “there is no doubt that in the next year or two, we’ll have a lot more information,” he said.
—Helen Lippman