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New Data Show That Lamotrigine Is Effective as Add-On Therapy in Patients With Partial Epilepsy
Data from the ARMOR study, an international, multi-center, randomized, double-blind, placebo-controlled trial, showed that the new once-daily, extended release formulation reduced partial seizures by 46 percent, while patients taking placebo experienced a reduction of 24 percent over the entire 19-week treatment period. The study also showed significant overall reduction in seizure frequency in both the escalation and maintenance treatment phases. In addition, the study showed that 42 percent of patients treated with Lamictal XR reduced their frequency of seizures by at least half by the end of the 19-week treatment period.
The second study, COMPASS, showed that patients could be switched from Lamictal immediate release (IR) to Lamictal XR while maintaining comparable blood levels of lamotrigine.
"These data are important because they show that the extended release formulation of Lamictal reduces the frequency of seizures. The once daily dosing regimen may also provide a more convenient treatment option for patients," said Dean Naritoku, M.D., Professor of Neurology and Pharmacology, Southern Illinois University, Springfield, IL. "In addition, when compared to Lamictal immediate release, given twice a day, the new investigational formulation demonstrated fewer daily fluctuations in serum concentration and more stable blood levels over time."
ABOUT THE ARMOR STUDY
In the ARMOR study, patients naïve to Lamictal, thirteen years of age or older with uncontrolled partial seizures, taking a stable regimen of 1 or 2 AEDs were enrolled in an 8 week baseline phase. Patients having 8 or more partial seizures were randomized to receive either once daily Lamictal XR or placebo. The treatment period consisted of escalation (7 weeks) and maintenance phases (12 weeks) with dosing based on background AEDs. The primary endpoint was percentage change from baseline in weekly partial seizures during the entire treatment phase.
Of 326 patients enrolled, 236 were randomized and included in the intent-to-treat population (116 Lamictal XR, 120 placebo). The median percent decrease from baseline in all partial seizures was 46 percent compared to 24 percent for placebo during the entire treatment phase, 28 percent compared to 16 percent during the escalation phase of treatment and 58 percent compared to 27 percent during the maintenance phase of treatment.
Time to ≥50 percent reduction in seizure frequency was analyzed using a two sided log-rank statistic. In patients taking Lamictal XR, 42 percent achieved ≥50 percent reduction in seizure frequency at the end of the treatment period. The time to achieve and maintain ≥50 percent reduction in seizure frequency with Lamictal XR was reached at day 18. During the 12-week maintenance period, the percent of patients with 100 percent decrease from baseline partial seizures were 19 percent and 5 percent (Lamictal XR vs. placebo).
The most common (>5 percent) drug-related adverse events for Lamictal XR and placebo, respectively, were dizziness, 18 vs. 5 percent, headache, 17 vs. 15 percent, somnolence, 7 vs. 4 percent, nausea, 7 vs. 2 percent, and diarrhea, 7 vs. 4 percent. The non-serious rash rate was 2 percent for Lamictal XR and
ABOUT THE COMPASS STUDY
The second trial (COMPASS) compared the pharmacokinetics of twice daily, immediate release Lamictal to once daily Lamictal XR in patients thirteen years of age and older with epilepsy. The open label, conversion study consisted of a 2 week base line phase with Lamictal immediate release, a 2 week treatment phase with Lamictal XR and a 1 week treatment phase with Lamictal immediate release. The study outcomes included lamotrigine pharmacokinetics upon conversion and seizure frequency during each treatment phase.
Results showed the steady state trough concentrations for Lamictal XR were equivalent to or higher than those of Lamictal immediate release depending on concomitant AED. In addition, there was no change in the median weekly seizure frequency among the groups.
Epilepsy, defined by recurrent unprovoked seizures, is a change in sensation, awareness, or behavior brought about by an electrical disturbance in the brain. The kind of seizure a person has depends on which part and how much of the brain is affected by the electrical disturbance that produces seizures. Generalized seizures are seizures that involve the entire brain from the outset. Partial seizures, which are more common, involve a restricted area of the brain. In approximately 70 percent of cases, the cause of epilepsy is unknown. According to the Epilepsy Foundation, more than three million Americans of all ages are living with epilepsy.
ABOUT LAMICTAL IMMEDIATE RELEASE (IR) FORMULATION
Lamictal is indicated 1) as adjunctive therapy for partial seizures, primary generalized tonic-clonic seizures, and the generalized seizures of Lennox-Gastaut syndrome in adults and pediatric patients as young as 2 years and 2) for conversion to monotherapy in adults with partial seizures taking carbamazepine, phenytoin, phenobarbital, primidone, or valproate as the single AED.
Safety and effectiveness of Lamictal have not been established 1) as initial monotherapy, 2) for conversion to monotherapy from AEDs other than carbamazepine, phenytoin, phenobarbital, primidone, or valproate, 3) for simultaneous conversion to monotherapy from 2 or more concomitant AEDs.
Lamictal is also approved for maintenance treatment of bipolar I disorder to delay the time to occurrence of mood episodes (depression, mania, hypomania, mixed episodes) in adult patients treated for acute mood episodes with standard therapy. The effectiveness of Lamictal in the acute treatment of mood episodes has not been established.
Serious rashes requiring hospitalization and discontinuation of treatment have been reported in association with the use of Lamictal. The incidence of these rashes, which have included Stevens Johnson syndrome, is approximately 0.8 percent (8 per 1000) in pediatric patients under the age of 16 years receiving Lamictal as adjunctive therapy for epilepsy, and 0.3 percent (3 per 1000) in adults on adjunctive therapy for epilepsy. In clinical trials of bipolar and other mood disorders, the rate of serious rash was 0.08 percent of adult patients who received Lamictal as initial monotherapy and 0.13 percent of adult patients who received Lamictal as adjunctive therapy. In a prospectively followed cohort of 1,983 pediatric patients taking adjunctive Lamictal, there was one rash-related death.