GlaxoSmithKline's Lamictal XR Extended-Release Tablets receive FDA approval

GlaxoSmithKline (NYSE: GSK) announced today that the U.S. Food and Drug Administration has approved Lamictal®XR™ (lamotrigine) Extended-Release Tablets as once-a-day, add-on therapy for epilepsy in patients ages 13 years and older with primary generalized tonic-clonic seizures.  This is an expanded label, as Lamictal XR is approved for partial onset seizures (with or without secondary generalization) for patients in this age group.

Primary generalized tonic-clonic seizures, known formerly as "grand mal" seizures, are considered the most common form of generalized (affecting both sides of the brain) seizure, occurring in approximately 20 percent of patients with epilepsy.  Patients experiencing a generalized tonic-clonic seizure usually lose consciousness and collapse.  This is followed by muscle stiffening (the tonic phase) and then jerking involving both sides of the body (the clonic phase).  

In a clinical study, the addition of Lamictal XR reduced seizure frequency more than placebo in patients with uncontrolled primary generalized tonic-clonic seizures, when used in adjunctive therapy for patients 13 years of age and older.  The patients in the study were not adequately controlled despite being on one or two anti-epileptic drugs.  

"We were encouraged that the study showed such a significant reduction in the number of primary generalized tonic-clonic seizures in patients who received Lamictal XR in addition to their current regimen.  Over the 19 week treatment period, the median percent reduction in weekly seizure frequency was 75 percent in patients treated with Lamictal XR compared to 32 percent for those taking placebo," said Victor Biton, M.D., director of the Arkansas Epilepsy Program and Clinical Trials, Inc., in Little Rock, Ark.  "The approval of once-a-day Lamictal XR for this very serious seizure type gives us a convenient and effective new option for improving the care of our patients with epilepsy."

The most common adverse event was headache, which was reported among 14 percent of patients taking Lamictal XR and 16 percent of patients taking placebo. Other common adverse events in patients taking Lamictal XR included vomiting (10 percent), nausea (7 percent), fever (7 percent), dizziness (6 percent), double vision (6 percent), tremor (6 percent), nasopharyngitis (3 percent), rash (3 percent) and anxiety (3 percent).

Lamictal XR was initially approved in May 2009 for the treatment of partial onset seizures with or without secondary generalization in adults or adolescents. Partial onset seizures, which are limited to one part of the brain, are the most common type of seizure experienced by people with epilepsy.  Partial seizures may sometimes spread to both sides of the brain, an occurrence classified as secondary generalization. The safety and effectiveness of Lamictal XR have not been established in patients under the age of 13.  

Patients with generalized tonic-clonic seizures currently taking immediate-release Lamictal twice-daily can be converted directly to once-a-day Lamictal XR using the same total daily dose.

Patented GlaxoSmithKline Extended-Release Technology

Lamictal XR Extended-Release Tablets are enteric-coated and contain a modified release formulation in the center of the tablet. There is a specially designed opening in the enteric coating on both sides of the tablet that utilizes a new technology called DiffCORE™, discovered and developed by GlaxoSmithKline. This allows a controlled release of the medicine in the acidic environment of the stomach, leading to a gradual release of lamotrigine into the bloodstream.