As of 21st Oct Onfi (clobazam) tablets are FDA (U.S. Food and Drug Administration) approved as an add on treatment for seizures caused by Lennox-Gastaut syndrome in adults and children aged 2 years and older. The disease effects fewer than 200,000 people in the United States so it was granted what as known as “orphan status”. Russell Katz, M.D., director of the Division of Neurology Products in the FDA’s Center for Drug Evaluation and Research was pleased with the approval :

“Lennox-Gastaut syndrome is a severe form of epilepsy that causes debilitating seizures …This is a difficult condition to treat, and it will be helpful to have an additional treatment option.”

Lennox-Gastaut syndrome often starts around the age of four and can be caused by a number of issues which include brain malformations, severe head injuries, central nervous system infections, and inherited degenerative or metabolic conditions.

30 to 35 percent of patients have no apparent cause. Patients usually experience a wide variety of frequent seizures, 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.

Onfi, was added to ongoing seizure medication, and its performance established in two multicenter controlled studies of patients 2 years of age and older. In each study, the drug was analysed for the degree 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. Both studies showed 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).

Onfi does have side effects though and when compared to those taking an inactive tablet (placebo) these 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.

Antiepileptic drugs in general may increase the risk of suicidal thoughts or behaviors in a very small number of people taking the drug and Onfi also carries this caution. Patients prescribed 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 and it is therefore important that patients on the drug do not drive, operate heavy machinery, or engage in other dangerous activities until they become used to how the drug might affect them. Onfi can cause abuse and dependence. It has been categorized as a Schedule IV drug under the Controlled Substances Act. Onfi also should not be discontinued suddenly. Patients 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.

Written by Rupert Shepherd