Safety and Efficacy of Gabapen for Pediatric (Regulatory Post Marketing Commitment Plan)

A treatment-related adverse event was any untoward medical occurrence attributed to gabapentin in a participant who received gabapentin. Relatedness to gabapentin was assessed by the investigator and sponsor (Pfizer Japan Inc.).

Clinical efficacy rate, which was defined as the percentage of participants who achieved clinical efficacy over the total number of efficacy analysis population, was presented along with the corresponding exact 2-sided 95% CI. For the basis of efficacy evaluation, frequencies of epileptic seizure were recorded during the previous 4 weeks from the treatment start date, and that from the end date of assessment period. Clinical efficacy was assessed according to the following categories: (1) effective, (2) not effective, or (3) not assessable.

A treatment-related adverse event was any untoward medical occurrence attributed to gabapentin in a participant who received gabapentin. Expectedness of the adverse event was determined according to the Japanese package insert. Relatedness to gabapentin was assessed by the investigator and sponsor (Pfizer Japan Inc.).

A treatment-related adverse event was any untoward medical occurrence attributed to gabapentin in a participant who received gabapentin. Participants with treatment-related adverse events were counted by each candidate risk factor (including gender, age, and disease eligible for the survey) to assess whether these were risk factors for the treatment-related adverse events. No inferential analyses of risk factors were performed because of a small number of the events (5 events).

Participants who responded to the treatment with gabapentin were counted by the baseline severity of epileptic seizure (mild, moderate and severe) to assess whether the baseline severity of epileptic seizure was a factor affecting the treatment efficacy.

Participants who responded to the treatment with gabapentin were counted by the baseline frequency of epileptic seizure (<=8 versus >8 episodes/per 4 weeks) to assess whether the baseline frequency of epileptic seizure was a factor affecting the treatment efficacy.

Participants who responded to the treatment with gabapentin were counted by the number of concomitant epileptic drugs at baseline across 5 categories (no drug, 1 drug, 2 drugs, 3 drugs, and 4 or more drugs) to assess whether the number of concomitant epileptic drugs at baseline was a factor affecting the treatment efficacy.

Participants who responded to the treatment with gabapentin were counted by the treatment period (non-long term [less than 1 year] or long term [1 year or more]) to assess whether the treatment period with gabapentin was a factor affecting the treatment efficacy.

Central nervous system depressant actions including somnolence and ataxia were determined as key survey items by the sponsor (Pfizer Japan Inc.). These events were defined according to MedDRA/J version 17.1 as the events classified in "psychiatric disorders" or "nervous system disorders" of the system organ classes, or those classified in "asthenia" or "gait disturbance" of the preferred terms. A treatment-related adverse event was any untoward medical occurrence attributed to gabapentin in a participant who received gabapentin. Relatedness to gabapentin was assessed by the investigator and sponsor.

Aggressive behaviors including affect lability and hostility were determined as key survey items by the sponsor (Pfizer Japan Inc.). These events were defined as the 101 preferred terms listed by pharmaceuticals and medical devices agency and classified according to MedDRA/J version 17.1. A treatment-related adverse event was any untoward medical occurrence attributed to gabapentin in a participant who received gabapentin. Relatedness to gabapentin was assessed by the investigator and sponsor.

R Ratio was calculated by the following formula, where B represented the baseline frequency of epileptic seizures during the previous 4 weeks from the treatment start date, whereas T represented the frequency of epileptic seizures during the previous 4 weeks from the end of assessment period: R Ratio = (T - B) / (T + B). R Ratio is within the range of -1 to +1, and a negative value represents a reduction in the frequency of seizure.

Responder rate, which was defined as the percentage of participants whose R ratio was - 0.333 or less, was presented along with the corresponding exact 2-sided 95% CI. R ratio of - 0.333 or less corresponded to the decrease of epileptic seizure frequency by 50% or more.

Reduction from baseline in epileptic seizure frequency was defined by the following formula, where B represented the baseline frequency of epileptic seizures during the previous 4 weeks from the treatment start date, whereas T represented the frequency of epileptic seizures during the previous 4 weeks from the end of assessment period: Reduction from baseline in epileptic seizure frequency (%) = [(T-B) / B] X 100. The median percentages were presented along with the corresponding minimum and maximum percentages.