Once-a-Day Epilepsy Drug Found Effective for Partial Seizures

SPRINGFIELD, Ill., Oct. 15 -- Patients taking an extended-release epilepsy drug once daily as adjunctive therapy nearly halved the number of partial seizures compared with those given a placebo, according to investigators here.

The 19-week double-blind, randomized, placebo-controlled study of extended release lamotrigine (Lamictal) was sponsored and conducted by GlaxoSmithKline, the drug's maker.

Those taking extended-release lamotrigine had 46% fewer partial seizures compared with 24% for those taking a placebo, and the drug was well-tolerated, Dean K. Naritoku, M.D., of Southern Illinois University, and colleagues reported in the Oct. 16 issue of Neurology.

"The more often people have to remember to take their medication each day, the more likely they are to a miss a dose, Dr. Naritoku said.

The study included 239 patients from the U.S. and several countries in Europe, Asia, and South America. The patients older than 12 were diagnosed with epilepsy with partial seizures not fully controlled by medication and were taking one to two baseline antiepileptic drugs.

They were randomized to adjunctive once-daily extended-release lamotrigine (118 patients) or placebo (121 patients).

The 19-week study started with a baseline phase, followed by a seven-week double-blind escalation phase and a 12-week double-blind maintenance phase. During this time doses of study medication and concomitant antiepileptic drugs were maintained. Extended-release lamotrigine was given once daily to a target of 200 mg to 500 mg.

During the entire 19 weeks (dose-escalation plus maintenance phase) lamotrigine was more effective than placebo for median percent reduction from baseline in weekly partial seizures: 46.1% versus 24.2%, P = 0.0004 via Wilcoxon test, the researchers reported.

During the escalation phase of the study, lamotrigine scored 28.0% versus 16.3%, P= 0.028; and during the maintenance phase, 58.0% versus 26.7%, P

In addition, the percentage of patients who reduced partial seizures by at least half was 42.2% versus 24.2%, (P= 0.0037) and time to 50% or greater reduction in partial seizure frequency (P = 0.0007) also favored lamotrigine over placebo.

There were similar results for secondarily generalized seizures, the investigators reported.

The tolerability and safety profiles for lamotrigine as adjunctive therapy were favorable, the researchers said. The percentage of at least one adverse event was 69% in the lamotrigine group and 62% in the placebo group.

The most common adverse events were headache (lamotrigine 17%, placebo 15%) and dizziness (lamotrigine 18% versus placebo 5%).

Although dizziness was the most common adverse event for the extended release drug, the incidence of dizziness was lower than that reported in controlled studies of immediate-release lamotrigine, the researchers said.

Non-serious rash was reported as an adverse event by two patients taking lamotrigine, and one of these patients withdrew from the study. No serious rashes were observed in either group.

Differences between extended release lamotrigine and placebo on health outcomes measures were not significant, and the health outcome data were inconclusive, the researchers said.

These results support the clinical utility of this once-daily formulation, the researchers said.

Dr. Naritoku reported that he has carried out clinical trials for GlaxoSmithKline and other pharmaceutical companies. He is also on the speakers bureau for GSK (