On Oct. 21, the U.S. Food and Drug Administration approved Onfi" data-scaytid="1">Onfi tablets (clobazam" data-scaytid="3">clobazam) for use as an adjunctive (add-on) treatment for seizures associated with Lennox-Gastaut syndrome in adults and children 2 years of age and older.
As Onfi is intended to treat a disease or condition that affects fewer than 200,000 people in the United States, it was granted orphan drug designation by the FDA.
“Lennox-Gastaut syndrome is a severe form of epilepsy that causes debilitating seizures,” said Russell Katz, MD, director of the Division of Neurology Products in the FDA’s Center for Drug Evaluation and Research. “This is a difficult condition to treat, and it will be helpful to have an additional treatment option.”
Lennox-Gastaut syndrome usually begins before 4 years of age, and can be caused by a number of conditions, including brain malformations, severe head injuries, central nervous system infections, and inherited degenerative or metabolic conditions. In 30 to 35 percent of patients, no cause can be found.
Patients commonly have frequent seizures of a wide variety, including tonic (stiffening of the body, upward deviation of the eyes, dilation of the pupils, and altered respiratory patterns), atonic (brief loss of muscle tone and consciousness, causing abrupt falls), atypical absence (staring spells), and myoclonic (sudden muscle jerks).
Most children with Lennox-Gastaut syndrome experience some degree of impaired intellectual functioning or information processing, as well as developmental delays and behavioral disturbances.
The effectiveness of Onfi, when added to ongoing seizure medication, was established in two multicenter controlled studies of patients 2 years of age and older. In each study, the drug was tested for the amount of reduction in the weekly frequency of drop seizures (atonic, tonic, or myoclonic seizures resulting in a fall or loss of posture) from the 4-week baseline period to a maintenance period. In both studies, patients taking Onfi had improved seizure control when compared to those taking control treatment (placebo in one study and low-dose Onfi in the other study).
Common adverse reactions reported by patients taking Onfi compared to those taking an inactive tablet (placebo) included somnolence, sedation, fever, drooling, constipation, cough, urinary tract infection, sleeplessness (insomnia), aggression, fatigue, upper respiratory tract infection, irritability, vomiting, problems swallowing (dysphagia), problems with coordination (ataxia), bronchitis, and pneumonia.
Like other antiepileptic drugs, Onfi may increase the risk of suicidal thoughts or behaviors in a very small number of people taking the drug. Patients taking antiepileptic drugs should be monitored for depression, suicidal thoughts or behavior, and unusual changes in mood or behavior.
Onfi may slow thinking and impair motor skills; so, it is important that people taking the drug not drive, operate heavy machinery, or engage in other dangerous activities until they know how the drug affects them. Onfi can cause abuse and dependence. It has been categorized as a Schedule IV drug under the Controlled Substances Act. Onfi should not be discontinued suddenly. People using the drug should talk with their health care professional about slowly stopping the drug to avoid withdrawal symptoms.
The FDA is requiring that a Medication Guide be given to patients and caregivers when Onfi is dispensed. The Medication Guide describes the risks and adverse reactions people should be mindful of when using the product.
Onfi is manufactured by Catalent Pharma Solutions LLC, Winchester, Ky., for Lundbeck Inc. of Deefield, Ill.