Oral delta-9-tetrahydracannabinol (delta-9-THC) and palmitoylethanolamide (PEA), in a proprietary combination known as THX-110, is promising for reducing tic symptoms in adults with Tourette syndrome (TS), new research suggests.
In a small phase 2 trial, investigators administered THX-110 to 16 adults with treatment-resistant TS for 12 weeks. Results showed a reduction of more than 20% in tic symptoms after the first week of treatment compared with baseline.
“We conducted an uncontrolled study in adults with severe TS and found that their tics improved over time while they took THX-110,” lead author Michael Bloch, MD, associate professor and co-director of the Tic and OCD Program at the Child Study Center, Yale University, New Haven, Conn., told this news organization.
Dr. Bloch added that the next step in this line of research will be to conduct a placebo-controlled trial of the compound in order to assess whether tic improvement observed over time in this study “was due to the effects of the medication and not related to the natural waxing-and-waning course of tic symptoms or treatment expectancy.”
The findings were published online August 2 in the Journal of Neuropsychiatry and Clinical Neurosciences.
‘Entourage effect’
“Several lines of evidence from clinical observation and even randomized controlled trials” suggest that cannabis (cannabis sativa) and delta-9-THC may be effective in treatment of tic disorders, Dr. Bloch said.
“Cannabinoid receptors are present in the motor regions important for tics, and thus, there is a potential mechanism of action to lead to improvement of tics,” he added.
However, “the major limitations of both cannabis and dronabinol [a synthetic form of delta-9-THC] use are the adverse psychoactive effects they induce in higher doses,” he said.
Dr. Bloch noted that PEA is a lipid messenger “known to mimic several endocannabinoid-driven activities.”
For this reason, combining delta-9-THC with PEA is hypothesized to reduce the dose of delta-9-THC needed to improve tics and also potentially lessen its side effects.
This initial open-label trial examined safety and tolerability of THX-110, as well as its effect on tic symptoms in adults with TS. The researchers hoped to “use the entourage effect to deliver the therapeutic benefits of delta-9-THC in reducing tics with decrease psychoactive effects by combining with PEA.”
The “entourage effect” refers to “endocannabinoid regulation by which multiple endogenous cannabinoid chemical species display a cooperative effect in eliciting a cellular response,” they write.
The investigators conducted a 12-week uncontrolled trial of THX-110, used at its maximum daily dose of delta-9-THC (10 mg) and a constant 800-mg dose of PEA in 16 adults with TS (mean age, 35 years; mean TS illness duration, 26.6 years).
Participants had a mean baseline Yale Global Tic Severity Scale (YGTSS) score of 38.1 and a mean worst-ever total tic score of 45.4.
All participants were experiencing persistent tics, despite having tried an array of previous evidence-based treatments for TS, including antipsychotics, alpha-2 agonists, VMAT2 inhibitors, benzodiazepines, and topiramate (Topamax).
Significant improvement
Results showed significant improvement in tic symptoms with TXH-110 treatment over time (general linear model time factor: F = 3.06, df = 7.91, P = .006).
At first assessment point, mean YGTSS improvement was 3.5 (95% confidence interval, 0.1-6.9; P = .047). The improvement not only remained significant but continued to increase throughout the 12-week trial period.
At 12 weeks, the maximal improvement in tic symptoms was observed, with a mean YGTSS improvement at endpoint of 7.6 (95% CI, 2.5-12.8; P = .007).
Four patients experienced a greater than 35% improvement in tic symptoms during the trial, whereas 6 experienced a 25% or greater improvement. The mean improvement in tic symptoms over the course of the trial was 20.6%.
There was also a significant improvement between baseline and endpoint on other measures of tic symptoms – but not on premonitory urges.
The patients experienced “modest” but not significant improvement in comorbid symptoms, including attentional, anxiety, depressive, and obsessive-compulsive symptoms.