This open-label study was designed to evaluate the long-term tolerability and efficacy of
lamotrigine in 1- to 24-month-old infants with
partial seizures. The study enrolled both
lamotrigine-naïve patients and patients who had been previously exposed to
lamotrigine in a randomized, double-blind, placebo-controlled study. Patients (n = 204) received
lamotrigine according to a dosing schedule that depended on prior experience with
lamotrigine and concurrent
antiepileptic drug therapy for up to 48 weeks or their second birthday, whichever occurred last. Total duration of
lamotrigine exposure (which included exposure during the placebo-controlled study in
lamotrigine-experienced patients) was >/=24 weeks in 92% of patients, >/=48 weeks in 70% of patients, and >/=72 weeks in 20% of patients. A total of 20 (10%) patients (8
lamotrigine-naïve patients and 12
lamotrigine-experienced patients) transitioned to
lamotrigine monotherapy. The most common adverse events were
pyrexia (45% of patients),
upper-respiratory tract infection (28%), and
ear infection (22%). The only adverse event considered reasonably attributable to study medication in >2% of patients was irritability (n = 10; 5% of patients). No cases of serious
rash were reported. The median percent reduction from baseline in partial seizure frequency in the sample as a whole was 74%. Seizure frequency was reduced by >/=50% from pre-
lamotrigine baseline in 62% of patients in the sample as a whole, 60% of the
lamotrigine-naïve subgroup, and 63% of the
lamotrigine-experienced subgroup. In the sample as a whole, 13% of patients were seizure free during the Treatment Phase. Investigators considered clinical status at the last
clinic visit to be improved (mildly, moderately, or markedly) relative to prelamotrigine clinical status in 76% of patients (150/197) and to be unchanged in 19% (37/197). In this study-the first large prospective investigation of the long-term tolerability and efficacy of an
antiepileptic drug in a patient population 2 years and younger-
lamotrigine administered for up to approximately 72 weeks was well tolerated and associated with good seizure control.