Cannabidiol as a new treatment for drug-resistant epilepsy in tuberous sclerosis complex.

OBJECTIVE: Tuberous sclerosis complex (TSC) is an autosomal-dominant genetic disorder with highly variable expression. The most common neurologic manifestation of TSC is epilepsy, which affects approximately 85% of patients, 63% of whom develop treatment-resistant epilepsy. Herein, we evaluate the efficacy, safety, and tolerability of cannabidiol (CBD), a nonpsychoactive compound derived from the marijuana plant, as an adjunct to current antiepileptic drugs in patients with refractory seizures in the setting of TSC. METHODS: Eighteen of the 56 patients who have enrolled in our current expanded-access study of cannabidiol for patients with treatment-resistant epilepsy carry a diagnosis of TSC. After an initial baseline period of 1 month, patients began treatment with CBD. The initial dose of 5 mg/kg/day was increased by 5 mg/kg/day every week up to a maximum dose of 50 mg/kg/day, if tolerated. Weekly seizure frequencies, percent change in seizure frequencies, and responder rates were calculated during the 2nd, 3rd, 6th, 9th, and 12th month of treatment with CBD. RESULTS: The median weekly seizure frequency during the baseline period was 22.0 (interquartile range [IQR] 14.8-57.4), which decreased to 13.3 (IQR 5.1-22.1) after 3 months of treatment with cannabidiol. The median percent change in total weekly seizure frequency was -48.8% (IQR -69.1% to -11.1%) after 3 months of treatment. The 50% responder rates over the course of the study were 50%, 50%, 38.9%, 50%, and 50% after 2, 3, 6, 9, and 12 months of treatment with CBD, respectively. In patients taking clobazam concurrently with CBD (n = 12), the responder rate after 3 months of treatment was 58.3%, compared to 33.3% in patients not taking clobazam (n = 6). Twelve (66.7%) of 18 patients in this study experienced at least one adverse event thought possibly related to CBD; the most common adverse events were drowsiness (n = 8, 44.4%), ataxia (n = 5, 27.8%), and diarrhea (n = 4, 22.2%). SIGNIFICANCE: Although double-blind, placebo-controlled trials are still necessary, these findings suggest that cannabidiol may be an effective and well-tolerated treatment option for patients with refractory seizures in TSC.

Drug-drug interaction between clobazam and cannabidiol in children with refractory epilepsy.

OBJECTIVE: Under an expanded access investigational new drug (IND) trial, cannabidiol (CBD) is being studied as a possible adjuvant treatment of refractory epilepsy in children. Of the 25 subjects in the trial, 13 were being treated with clobazam (CLB). Because CLB and CBD are both metabolized in the cytochrome P450 (CYP) pathway, we predicted a drug-drug interaction, which we evaluate in this article. METHODS: Thirteen subjects with refractory epilepsy concomitantly taking CLB and CBD under IND 119876 were included in this study. Demographic information was collected for each subject including age, sex, and etiology of seizures, as well as concomitant antiepileptic drugs (AEDs). CLB, N-desmethylclobazam (norclobazam; nCLB), and CBD levels were measured over the course of CBD treatment. CLB doses were recorded at baseline and at weeks 4 and 8 of CBD treatment. Side effects were monitored. RESULTS: We report elevated CLB and nCLB levels in these subjects. The mean (± standard deviation [SD]) increase in CLB levels was 60 ± 80% (95% confidence interval (CI) [-2-91%] at 4 weeks); the mean increase in nCLB levels was 500 ± 300% (95% CI [+90-610%] at 4 weeks). Nine of 13 subjects had a >50% decrease in seizures, corresponding to a responder rate of 70%. The increased CLB and nCLB levels and decreases in seizure frequency occurred even though, over the course of CBD treatment, CLB doses were reduced for 10 (77%) of the 13 subjects. Side effects were reported in 10 (77%) of the 13 subjects, but were alleviated with CLB dose reduction. SIGNIFICANCE: Monitoring of CLB and nCLB levels is necessary for clinical care of patients concomitantly on CLB and CBD. Nonetheless, CBD is a safe and effective treatment of refractory epilepsy in patients receiving CLB treatment.

Gastrointestinal problems in 15q duplication syndrome.

Chromosome 15q duplication syndrome (Dup15q syndrome) is a neurodevelopmental disorder involving copy number gains of the maternal chromosome 15q11.2-q13 region, characterized by intellectual disability, developmental delay, autism spectrum disorder (ASD), and epilepsy. Gastrointestinal (GI) problems in Dup15q syndrome have been reported only rarely, mostly focused on neonatal feeding difficulties. A retrospective review of the medical records of 46 patients with Dup15q syndrome was conducted to assess GI issues and their treatments in this population. GI symptoms were present in 76.7% of subjects with an isodicentric duplication and 87.5% with an interstitial duplication. There was no clear association between GI issues and ASD, with symptoms occurring in 78.9% of all subjects and 78.2% of ASD subjects. The most commonly reported symptoms were gastroesophageal reflux (56.7%) and constipation (60%), with 30% of subjects reporting both. The most common treatments were polyethylene glycol for constipation and proton pump inhibitors for reflux. Behaviors such as irritability and aggressiveness improved with treatment of GI symptoms in several subjects. The results indicate that GI symptoms are common in Dup15q syndrome and may have an atypical presentation. Diagnosis may be difficult, especially in individuals who are nonverbal or minimally verbal, so increased awareness is critical for early diagnosis and treatment.