Results of Six-Year, Open-Label Extension Study Evaluating ONFI (clobazam) CIV Published in Epilepsia
March 11, 2014
Results from a long-term, open-label extension study evaluating ONFI (clobazam) CIV for the adjunctive treatment of drop seizures associated with Lennox-Gastaut syndrome (LGS) were published online in the journal Epilepsia. ONFI, a 1,5-benzodiazepine, is indicated for the adjunctive treatment of seizures associated with LGS in patients 2 years of age and older. It is a federally controlled schedule four substance (CIV).
The study enrolled patients 2 to 60 years old with a current or prior diagnosis of LGS who had completed one of two double-blind clinical trials evaluating ONFI as adjunctive therapy for seizures associated with LGS. Qualifying patients were given the option of tapering off ONFI or continuing in the open-label extension study. The study was conducted to assess the long-term safety and efficacy of ONFI in this patient population.
Patient Retention, Mean Dosage and Safety Results
Of the 306 adults and children previously enrolled in the earlier two studies, 267 patients entered the extension study, and 70 percent (188) remained in the study through its conclusion. The mean modal ONFI dosage was 0.90 mg/kg/day up to Year 1, and 0.97 mg/kg/day up to Year 5.1
The most common adverse events experienced in the study (≥15%) included upper respiratory tract infection, pneumonia, somnolence, fall, otitis media and urinary tract infection. A total of 79 patients (29.6%) discontinued the study for the following reasons: patient/parent/caregiver request (33 patients), lack of efficacy, adverse events, death and “other reasons”.
“This is the largest and longest study to date evaluating an antiepileptic drug in the Lennox-Gastaut syndrome patient population,” said Joan A. Conry, M.D., professor of neurology at Children’s National Health System in Washington, D.C., and lead author of the study. “Because of the severity of LGS, an epilepsy syndrome that begins in childhood and persists over many years into adulthood, it’s important that we have this long-term data in such a large group of both children and adults.”
For complete efficacy and safety results, see the “Early View” section of the Epilepsia Web site.
Further Study Background
This multicenter, open-label extension study of ONFI (clobazam) was designed to assess the long-term safety and efficacy of open-label ONFI as adjunctive therapy for patients with seizures associated with LGS. The study included 267 qualifying patients who had completed one of two randomized controlled trials – a Phase II dose-ranging study (N=68) or a pivotal Phase III study (N=238; CONTAIN Trial). Patients were eligible to continue on to the open-label study if no more than 14 days elapsed since their last dose in the dose-ranging study (Phase II) or the CONTAIN Trial (Phase III).
For patients from the CONTAIN Trial, ONFI was started at a target dosage of 0.5 mg/kg/day (maximum 40 mg/day). This dosage was maintained for 48 hours, and thereafter adjusted per clinical need. For patients from the dose-ranging study who chose to continue in the open-label study, the unblinded physician adjusted or maintained the dosage that the patient was previously receiving.
About Lennox-Gastaut Syndrome
LGS is a rare and severe form of epilepsy that is typically diagnosed in childhood and often persists into adulthood. LGS is associated with multiple types of seizures, and daily seizures are common. Some of these seizures, including atonic, tonic and myoclonic seizures, may cause falls, or “drop seizures” (also referred to as “drop attacks”), which may result in injury.
About ONFI® (clobazam) CIV
ONFI is an oral antiepileptic drug developed in the United States by Lundbeck, and is available in 10 and 20 mg tablets, and as a 2.5 mg/mL Oral Suspension. ONFI is a 1,5-benzodiazepine. The exact mechanism of action for ONFI is not fully understood, but is thought to involve potentiation of GABAergic neurotransmission resulting from binding at the benzodiazepine site of the GABAA receptor. More than 300,000 prescriptions of ONFI have been written in the United States.
Read more here.