Pharmacokinetic Drug-Drug Interaction With Coadministration of Cannabidiol and Everolimus in a Phase 1 Healthy Volunteer Trial.

When highly purified cannabidiol (CBD; Epidiolex) and the mammalian target of rapamycin inhibitor everolimus are used concomitantly in the treatment of tuberous sclerosis complex, there is evidence of a pharmacokinetic (PK) interaction, leading to increased everolimus systemic exposure. We evaluated the effect of steady-state CBD exposure following multiple clinically relevant CBD doses on everolimus PK in healthy adult participants in a single-center, fixed-sequence, open-label, phase 1 study. All participants received oral everolimus 5 mg on day 1, followed by a 7-day washout. On days 9-17, participants received CBD (100 mg/mL oral solution) at 12.5 mg/kg in the morning and evening. On the morning of day 13, participants also received a single dose of oral everolimus 5 mg. Medications were taken 30 or 45 minutes (morning or evening dose) after starting a standardized meal. Maximum concentration and area under the concentration-time curve (AUC) from time of dosing to the last measurable concentration and extrapolated to infinity, of everolimus in whole blood were estimated using noncompartmental analysis, with geometric mean ratios and 90% confidence intervals for the ratios of everolimus dosed with CBD to everolimus dosed alone. A single dose of everolimus 5 mg was well tolerated when administered with multiple doses of CBD. Log-transformed everolimus maximum concentration, AUC from time of dosing to the last measurable concentration, and AUC extrapolated to infinity values increased by ≈2.5-fold, and everolimus half-life remained largely unchanged in the presence of steady-state CBD relative to everolimus dosed alone. Everolimus blood concentration monitoring should be strongly advised with appropriate dose reduction when coadministered with CBD.

A Phase II Randomized Trial to Explore the Potential for Pharmacokinetic Drug-Drug Interactions with Stiripentol or Valproate when Combined with Cannabidiol in Patients with Epilepsy.

BACKGROUND: In recent randomized, placebo-controlled, phase III trials, highly purified cannabidiol demonstrated efficacy with an acceptable safety profile in patients with Lennox-Gastaut syndrome or Dravet syndrome. It is anticipated that antiepileptic drugs such as stiripentol and valproate will be administered concomitantly with cannabidiol. OBJECTIVES: This trial evaluated the effect of cannabidiol on steady-state pharmacokinetics of stiripentol or valproate in patients with epilepsy, and the safety and tolerability of cannabidiol. METHODS: This phase II, two-arm, parallel-group, double-blind, randomized, placebo-controlled trial recruited male and female patients with epilepsy aged 16-55 years. Patients receiving a stable dose of stiripentol or valproate were randomized 4:1 to receive concomitant double-blind cannabidiol or placebo. Patients received plant-derived, highly purified cannabidiol medicine (Epidiolex® in the USA; Epidyolex® in the EU; 100 mg/mL oral solution) at a dose of 20 mg/kg/day from day 12 to 26, following a 10-day dose-escalation period. Blood samples for pharmacokinetic evaluations were collected on days 1 and 26 before stiripentol/valproate dosing and up to 12 h postdose. Treatment-emergent adverse events (AEs) were recorded. RESULTS: In total, 35 patients were recruited to the stiripentol arm (n = 14) or the valproate arm (n = 21). Both the safety and the pharmacokinetic populations of the stiripentol arm comprised 14 patients (2 placebo; 12 cannabidiol). The safety population of the valproate arm comprised 20 patients (4 placebo; 16 cannabidiol; one withdrew before receiving treatment); the pharmacokinetic population comprised 15 patients (3 placebo; 12 cannabidiol). Concomitant cannabidiol led to a small increase in stiripentol exposure (17% increase in maximum observed plasma concentration [Cmax]; 30% increase in area under the concentration-time curve over the dosing interval [AUCtau]). Concomitant cannabidiol also had little effect on valproate exposure (13% decrease in Cmax; 17% decrease in AUCtau) or its metabolite, 2-propyl-4-pentenoic acid (4-ene-VPA) (23% decrease in Cmax; 30% decrease in AUCtau). All changes in exposure are expressed as the dose-normalized geometric mean (CV%) day 26 to day 1 ratio. The most common AE was diarrhea; most AEs were mild. Two patients discontinued cannabidiol because of serious AEs (rash [n = 1] in the stiripentol arm; hypertransaminasemia [n = 1] in the valproate arm). A separate in vitro study investigated the bidirectional effect of cannabidiol, or its metabolite 7-carboxy-cannabidiol, on valproate plasma protein binding; no change in plasma protein binding was observed for either compound. CONCLUSIONS: The clinical relevance of the increase in stiripentol exposure is unknown; patients receiving cannabidiol and stiripentol concomitantly should be monitored for adverse reactions as individual patient responses may vary. Coadministration of cannabidiol did not affect the pharmacokinetics of valproate or its metabolite, 4-ene-VPA, in adult patients with epilepsy. Safety results were consistent with the known safety profile of cannabidiol at a dose of 20 mg/kg/day. Clinicaltrials.gov: NCT02607891.

Cannabidiol Does Not Convert to Δ9-Tetrahydrocannabinol in an In Vivo Animal Model.

Introduction: Cannabidiol (CBD) can convert to Δ9-tetrahydrocannabinol (THC) in vitro with prolonged exposure to simulated gastric fluid; however, in vitro conditions may not be representative of the in vivo gut environment. Using the minipig, we investigated whether enteral CBD converts to THC in vivo. Materials and Methods: Synthetic CBD (100 mg/mL) was administered orally in a sesame oil formulation twice daily to minipigs (N=3) in 15 mg/kg doses for 5 consecutive days. Blood samples were taken before and 1, 2, 4, and 6 h after morning doses on Days 1 and 5. Six hours after the final dose on Day 5, the animals were euthanized, and samples of gastrointestinal (GI) tract contents were obtained. Liquid chromatography with tandem mass spectrometry analysis determined CBD, THC, and 11-hydroxy-THC (11-OH-THC) concentrations. Lower limits of quantification: plasma CBD=1 ng/mL, plasma THC and 11-OH-THC=0.5 ng/mL, GI tract CBD=2 ng/mL, and GI tract THC and 11-OH-THC=1 ng/mL. Results: THC and 11-OH-THC were undetectable in all plasma samples. Maximum plasma concentrations (Cmax) of CBD were observed between 1 and 4 h on Days 1 and 5. CBD was present in plasma 6 h after administration on Days 1 (mean 33.6 ng/mL) and 5 (mean 98.8 ng/mL). Mean Cmax CBD values, 328 ng/mL (Day 1) and 259 ng/mL (Day 5), were within range of those achieved in clinical studies. Mean CBD exposure over 6 h was similar on Days 1 (921 h·ng/mL) and 5 (881 h·ng/mL). THC and 11-OH-THC were not detected in all GI tract samples. Mean CBD concentrations reached 84,500 ng/mL in the stomach and 43,900 ng/mL in the small intestine. Conclusions: Findings of the present study show that orally dosed CBD, yielding clinically relevant plasma exposures, does not convert to THC in the minipig, a species predictive of human GI tract function.