An Open-label Extension Study to Investigate Possible Drug-drug Interactions Between Clobazam and Cannabidiol

Jazz Pharmaceuticals

Status and phase: Completed; Phase 2

Conditions: Epilepsy

Treatments: Drug: Clobazam; Drug: GWP42003-P

Study type: Interventional

Funder types: Industry

Identifiers

NCT02564952

GWEP1428 Open-Label Extension

2014-002942-33 (EudraCT Number)

Details and patient eligibility

About

This study consisted of 2 parts: a double-blind (DB) phase and an open-label extension (OLE) phase. Only the OLE phase is described in this record. The OLE phase was a safety study. All participants received GWP42003-P initially titrated to 20 milligrams (mg)/kilograms (kg)/day; however, investigators subsequently decreased or increased the participant's dose to a maximum of 30 mg/kg/day (no minimum).

Enrollment: 18 patients

Sex: All

Ages: 18 to 65 years old

Volunteers: No Healthy Volunteers

Inclusion and exclusion criteria

Key Inclusion Criteria:

• Participant must have had epilepsy, as determined by the investigator, and must have been taking CLB.
• Participant must have had a documented magnetic resonance imaging/computerized tomography of the brain ruling out a progressive neurologic condition.
• Participant must have experienced at least 1 seizure of any type (that is, convulsive: tonic-clonic, tonic, clonic, atonic; focal: focal seizures with retained consciousness and a motor component, focal seizures with impaired consciousness, focal seizures evolving to bilateral secondary generalization) within the 2 months prior to randomization.
• Participant must have been taking CLB and no more than 2 other antiepileptic drugs (AEDs) during the course of the study. However, any participants who were taking these medications after screening were not withdrawn from the study unless there were safety concerns.
• AED(s), including CLB, must have been stable for 4 weeks prior to screening and regimen must have remained stable throughout the duration of the double-blind phase of the study.
• Intervention with vagus nerve stimulation and/or ketogenic diet must have been stable for 4 weeks prior to Baseline and participant/caregiver must have been willing to maintain a stable regimen throughout the double-blind phase of the study.

Key Exclusion Criteria:

• Participant had clinically significant unstable medical conditions other than epilepsy.
• Participants were on CLB at doses above 20 mg per day.
• Participants taking CLB intermittently as rescue medication.
• Participant had a history of symptoms related to a drop in blood pressure due to postural changes (for example, dizziness, light-headedness, blurred vision, palpitations, weakness, syncope).
• Participant had any history of suicidal behavior or any suicidal ideation of type 4 or 5 on the Columbia Suicide Severity Rating Scale in the last month or at screening.
• Participant had clinically relevant symptoms or a clinically significant illness, other than epilepsy in the 4 weeks prior to screening or enrollment, other than epilepsy.
• Participant had consumed alcohol during the 7 days prior to enrollment and was unwilling to abstain during the double-blind phase of the study.
• Participant was currently using or has in the past used recreational or medicinal cannabis, or synthetic cannabinoid-based medications (including Sativex®) within the 3 months prior to study entry.
• Participant had any known or suspected history of any drug abuse or addiction.
• Participant was unwilling to abstain from recreational or medicinal cannabis, or synthetic cannabinoid-based medications (including Sativex) for the duration for the study.
• Participant consumed grapefruit or grapefruit juice 7 days prior to enrollment and was unwilling to abstain from drinking grapefruit juice within 7 days of pharmacokinetic visits.
• Participant had any known or suspected hypersensitivity to cannabinoids or any of the excipients of the IMP, for example, sesame oil.
• Participant received an IMP within the 12 weeks prior to the screening visit.
• Participant had significantly impaired hepatic function at the screening or randomization visit, defined as any of the following: (A) Alanine aminotransferase (ALT) or aspartate aminotransferase (AST) > 5 × upper limit of normal (ULN). (B) ALT or AST > 3 × ULN and total bilirubin > 2 × ULN or international normalized ratio > 1.5. (C) ALT or AST > 3 × ULN with the presence of fatigue, nausea, vomiting, right upper quadrant pain or tenderness, fever, rash, and/or eosinophilia (> 5%).

Trial design

Primary purpose: Other

Allocation: N/A

Interventional model: Single Group Assignment

Masking: None (Open label)

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18 participants in 1 patient group

GWP42003-P

Experimental group

Description:

Participants who transferred from the DB phase (NCT02565108) to the OLE (still blinded at that stage) tapered off their GWP42003-P or placebo treatment by reducing their maintenance dose by 10% per day and concomitantly titrating GWP42003-P to 20 mg/kg/day initially for the OLE; doses could then be adjusted up or down, dependent on investigator opinion, to a maximum of 30 mg/kg/day GWP42003-P. Clobazam (CLB) was administered in line with the physician's preferred CLB dosing regimen for each participant.

Treatment:

Drug: GWP42003-P

Drug: Clobazam