Trial Outcomes & Findings for A Phase III Open-Label Study Of Gabapentin As Adjunctive Therapy In Japanese Pediatric Patients With Partial Seizures (NCT NCT00603473)

Last Updated: 2021-02-03

Results Overview

The Response Ratio calculated by the following equation was assessed as the primary endpoint: R Ratio = (T-B) / (T+B) where T is seizure frequency per 28 days (i.e., the number of seizures per 28 days) calculated from the total number of seizures for the 12-week treatment period, and B is seizure frequency per 28 days (i.e., the number of seizures per 28 days) calculated from the total number of seizures for the 6-week baseline period.

Recruitment status

COMPLETED

Study phase

PHASE3

Target enrollment

92 participants

Primary outcome timeframe

12 weeks

Results posted on

2021-02-03

Participant Flow

Participants were screened at 27 centers in Japan.

Ninety subjects were enrolled in the study. Of them, 89 received the study treatment, while 1 withdrew consent.

Participant milestones

Participant milestones
Measure	Gabapentin The dosage of oral solution for subjects aged 3 to 12 years was calculated based on their body weight. The dose was titrated for the first 3 days of the treatment period. Subjects aged 3 to 4 years received gabapentin 10 mg/kg/day on Day 1, 20 mg/kg/day on Day 2 and 40 mg/kg/day from Day 3. Subjects aged 5 to 12 years received gabapentin 10 mg/kg/day on Day 1, 20 mg/kg/day on Day 2 and 25 to 35 mg/kg/day from Day 3. Subjects aged 13 to 15 years received gabapentin 600 mg/day on Day 1, 1200 mg/day on Day 2 and 1200 or 1800 mg/day from Day 3. After Day 3, the dose was adjusted if necessary within the range of maintenance doses. The maximum daily dose was 600 mg for Day 1, 1200 mg for Day 2, and 1800 mg for Day 3 and thereafter.
Overall Study STARTED	89
Overall Study COMPLETED	80
Overall Study NOT COMPLETED	9

Reasons for withdrawal

Reasons for withdrawal
Measure	Gabapentin The dosage of oral solution for subjects aged 3 to 12 years was calculated based on their body weight. The dose was titrated for the first 3 days of the treatment period. Subjects aged 3 to 4 years received gabapentin 10 mg/kg/day on Day 1, 20 mg/kg/day on Day 2 and 40 mg/kg/day from Day 3. Subjects aged 5 to 12 years received gabapentin 10 mg/kg/day on Day 1, 20 mg/kg/day on Day 2 and 25 to 35 mg/kg/day from Day 3. Subjects aged 13 to 15 years received gabapentin 600 mg/day on Day 1, 1200 mg/day on Day 2 and 1200 or 1800 mg/day from Day 3. After Day 3, the dose was adjusted if necessary within the range of maintenance doses. The maximum daily dose was 600 mg for Day 1, 1200 mg for Day 2, and 1800 mg for Day 3 and thereafter.
Overall Study Adverse Event	4
Overall Study Lack of Efficacy	4
Overall Study Protocol Violation	1

Baseline Characteristics

A Phase III Open-Label Study Of Gabapentin As Adjunctive Therapy In Japanese Pediatric Patients With Partial Seizures

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	Gabapentin n=89 Participants The dosage of oral solution for subjects aged 3 to 12 years was calculated based on their body weight. The dose was titrated for the first 3 days of the treatment period. Subjects aged 3 to 4 years received gabapentin 10 mg/kg/day on Day 1, 20 mg/kg/day on Day 2 and 40 mg/kg/day from Day 3. Subjects aged 5 to 12 years received gabapentin 10 mg/kg/day on Day 1, 20 mg/kg/day on Day 2 and 25 to 35 mg/kg/day from Day 3. Subjects aged 13 to 15 years received gabapentin 600 mg/day on Day 1, 1200 mg/day on Day 2 and 1200 or 1800 mg/day from Day 3. After Day 3, the dose was adjusted if necessary within the range of maintenance doses. The maximum daily dose was 600 mg for Day 1, 1200 mg for Day 2, and 1800 mg for Day 3 and thereafter.
Age, Customized >= 3 years and < 5 years	11 Subjects n=5 Participants
Age, Customized >= 5 years and < 13 years	63 Subjects n=5 Participants
Age, Customized >= 13 years and =< 15 years	15 Subjects n=5 Participants
Sex: Female, Male Female	40 Participants n=5 Participants
Sex: Female, Male Male	49 Participants n=5 Participants

PRIMARY outcome

Timeframe: 12 weeks

Population: Modified intent-to-treat (MITT) population: Subjects who have received the study medication for at least 28 days and in whom the number of epileptic seizures used for efficacy assessment has been counted for at least 28 days in both the baseline and treatment periods.

Outcome measures

Outcome measures
Measure	Gabapentin n=86 Participants The dosage of oral solution for subjects aged 3 to 12 years was calculated based on their body weight. The dose was titrated for the first 3 days of the treatment period. Subjects aged 3 to 4 years received gabapentin 10 mg/kg/day on Day 1, 20 mg/kg/day on Day 2 and 40 mg/kg/day from Day 3. Subjects aged 5 to 12 years received gabapentin 10 mg/kg/day on Day 1, 20 mg/kg/day on Day 2 and 25 to 35 mg/kg/day from Day 3. Subjects aged 13 to 15 years received gabapentin 600 mg/day on Day 1, 1200 mg/day on Day 2 and 1200 or 1800 mg/day from Day 3. After Day 3, the dose was adjusted if necessary within the range of maintenance doses. The maximum daily dose was 600 mg for Day 1, 1200 mg for Day 2, and 1800 mg for Day 3 and thereafter.
Response Ratio of Gabapentin in Japanese Pediatric Patients With Partial Seizures	-0.158 ratio Interval -0.221 to -0.096

SECONDARY outcome

Timeframe: 12 weeks

Responder Rate was defined as the percentage of subjects with a 50% or greater reduction in the seizure frequency per 28 days for the 12-week treatment period in comparison with the frequency per 28 days for the 6-week baseline period.

Outcome measures

Outcome measures
Measure	Gabapentin n=86 Participants The dosage of oral solution for subjects aged 3 to 12 years was calculated based on their body weight. The dose was titrated for the first 3 days of the treatment period. Subjects aged 3 to 4 years received gabapentin 10 mg/kg/day on Day 1, 20 mg/kg/day on Day 2 and 40 mg/kg/day from Day 3. Subjects aged 5 to 12 years received gabapentin 10 mg/kg/day on Day 1, 20 mg/kg/day on Day 2 and 25 to 35 mg/kg/day from Day 3. Subjects aged 13 to 15 years received gabapentin 600 mg/day on Day 1, 1200 mg/day on Day 2 and 1200 or 1800 mg/day from Day 3. After Day 3, the dose was adjusted if necessary within the range of maintenance doses. The maximum daily dose was 600 mg for Day 1, 1200 mg for Day 2, and 1800 mg for Day 3 and thereafter.
Responder Rate	19.8 Percentage of Subjects Interval 12.0 to 29.8

SECONDARY outcome

Timeframe: 12 weeks

PCH calculated by the following equation was assessed as secondary endpoint: PCH = 100 (T-B) / B where T is seizure frequency per 28 days (i.e., the number of seizures per 28 days) calculated from the total number of seizures for the 12-week treatment period, and B is seizure frequency per 28 days (i.e., the number of seizures per 28 days) calculated from the total number of seizures for the 6-week baseline period.

Outcome measures

Outcome measures
Measure	Gabapentin n=86 Participants The dosage of oral solution for subjects aged 3 to 12 years was calculated based on their body weight. The dose was titrated for the first 3 days of the treatment period. Subjects aged 3 to 4 years received gabapentin 10 mg/kg/day on Day 1, 20 mg/kg/day on Day 2 and 40 mg/kg/day from Day 3. Subjects aged 5 to 12 years received gabapentin 10 mg/kg/day on Day 1, 20 mg/kg/day on Day 2 and 25 to 35 mg/kg/day from Day 3. Subjects aged 13 to 15 years received gabapentin 600 mg/day on Day 1, 1200 mg/day on Day 2 and 1200 or 1800 mg/day from Day 3. After Day 3, the dose was adjusted if necessary within the range of maintenance doses. The maximum daily dose was 600 mg for Day 1, 1200 mg for Day 2, and 1800 mg for Day 3 and thereafter.
Percent Change in Seizure Frequency (PCH)	-24.4 Percent Change Interval -100.0 to 192.9

Adverse Events

Gabapentin

Serious events: 1 serious events

Other events: 73 other events

Deaths: 0 deaths

Serious adverse events

Serious adverse events
Measure	Gabapentin n=89 participants at risk The dosage of oral solution for subjects aged 3 to 12 years was calculated based on their body weight. The dose was titrated for the first 3 days of the treatment period. Subjects aged 3 to 4 years received gabapentin 10 mg/kg/day on Day 1, 20 mg/kg/day on Day 2 and 40 mg/kg/day from Day 3. Subjects aged 5 to 12 years received gabapentin 10 mg/kg/day on Day 1, 20 mg/kg/day on Day 2 and 25 to 35 mg/kg/day from Day 3. Subjects aged 13 to 15 years received gabapentin 600 mg/day on Day 1, 1200 mg/day on Day 2 and 1200 or 1800 mg/day from Day 3. After Day 3, the dose was adjusted if necessary within the range of maintenance doses. The maximum daily dose was 600 mg for Day 1, 1200 mg for Day 2, and 1800 mg for Day 3 and thereafter.
Infections and infestations Pharyngitis	1.1% 1/89 • 12-week treatment period, and 1-week follow-up period The same event may appear as both an AE and a SAE. However, what is presented are distinct events. An event may be categorized as serious in one subject and as nonserious in another subject, or one subject may have experienced both a serious and nonserious event during the study.

Other adverse events

Other adverse events
Measure	Gabapentin n=89 participants at risk The dosage of oral solution for subjects aged 3 to 12 years was calculated based on their body weight. The dose was titrated for the first 3 days of the treatment period. Subjects aged 3 to 4 years received gabapentin 10 mg/kg/day on Day 1, 20 mg/kg/day on Day 2 and 40 mg/kg/day from Day 3. Subjects aged 5 to 12 years received gabapentin 10 mg/kg/day on Day 1, 20 mg/kg/day on Day 2 and 25 to 35 mg/kg/day from Day 3. Subjects aged 13 to 15 years received gabapentin 600 mg/day on Day 1, 1200 mg/day on Day 2 and 1200 or 1800 mg/day from Day 3. After Day 3, the dose was adjusted if necessary within the range of maintenance doses. The maximum daily dose was 600 mg for Day 1, 1200 mg for Day 2, and 1800 mg for Day 3 and thereafter.
Eye disorders Conjunctivitis	3.4% 3/89 • 12-week treatment period, and 1-week follow-up period The same event may appear as both an AE and a SAE. However, what is presented are distinct events. An event may be categorized as serious in one subject and as nonserious in another subject, or one subject may have experienced both a serious and nonserious event during the study.
Gastrointestinal disorders Diarrhoea	6.7% 6/89 • 12-week treatment period, and 1-week follow-up period The same event may appear as both an AE and a SAE. However, what is presented are distinct events. An event may be categorized as serious in one subject and as nonserious in another subject, or one subject may have experienced both a serious and nonserious event during the study.
Gastrointestinal disorders Nausea	3.4% 3/89 • 12-week treatment period, and 1-week follow-up period The same event may appear as both an AE and a SAE. However, what is presented are distinct events. An event may be categorized as serious in one subject and as nonserious in another subject, or one subject may have experienced both a serious and nonserious event during the study.
General disorders Pyrexia	5.6% 5/89 • 12-week treatment period, and 1-week follow-up period The same event may appear as both an AE and a SAE. However, what is presented are distinct events. An event may be categorized as serious in one subject and as nonserious in another subject, or one subject may have experienced both a serious and nonserious event during the study.
Infections and infestations Influenza	10.1% 9/89 • 12-week treatment period, and 1-week follow-up period The same event may appear as both an AE and a SAE. However, what is presented are distinct events. An event may be categorized as serious in one subject and as nonserious in another subject, or one subject may have experienced both a serious and nonserious event during the study.
Infections and infestations Nasopharyngitis	27.0% 24/89 • 12-week treatment period, and 1-week follow-up period The same event may appear as both an AE and a SAE. However, what is presented are distinct events. An event may be categorized as serious in one subject and as nonserious in another subject, or one subject may have experienced both a serious and nonserious event during the study.
Infections and infestations Pharyngitis	6.7% 6/89 • 12-week treatment period, and 1-week follow-up period The same event may appear as both an AE and a SAE. However, what is presented are distinct events. An event may be categorized as serious in one subject and as nonserious in another subject, or one subject may have experienced both a serious and nonserious event during the study.
Infections and infestations Rhinitis	3.4% 3/89 • 12-week treatment period, and 1-week follow-up period The same event may appear as both an AE and a SAE. However, what is presented are distinct events. An event may be categorized as serious in one subject and as nonserious in another subject, or one subject may have experienced both a serious and nonserious event during the study.
Infections and infestations Upper respiratory tract infection	4.5% 4/89 • 12-week treatment period, and 1-week follow-up period The same event may appear as both an AE and a SAE. However, what is presented are distinct events. An event may be categorized as serious in one subject and as nonserious in another subject, or one subject may have experienced both a serious and nonserious event during the study.
Injury, poisoning and procedural complications Contusion	6.7% 6/89 • 12-week treatment period, and 1-week follow-up period The same event may appear as both an AE and a SAE. However, what is presented are distinct events. An event may be categorized as serious in one subject and as nonserious in another subject, or one subject may have experienced both a serious and nonserious event during the study.
Injury, poisoning and procedural complications Excoriation	3.4% 3/89 • 12-week treatment period, and 1-week follow-up period The same event may appear as both an AE and a SAE. However, what is presented are distinct events. An event may be categorized as serious in one subject and as nonserious in another subject, or one subject may have experienced both a serious and nonserious event during the study.
Injury, poisoning and procedural complications Fall	7.9% 7/89 • 12-week treatment period, and 1-week follow-up period The same event may appear as both an AE and a SAE. However, what is presented are distinct events. An event may be categorized as serious in one subject and as nonserious in another subject, or one subject may have experienced both a serious and nonserious event during the study.
Metabolism and nutrition disorders Increased appetite	3.4% 3/89 • 12-week treatment period, and 1-week follow-up period The same event may appear as both an AE and a SAE. However, what is presented are distinct events. An event may be categorized as serious in one subject and as nonserious in another subject, or one subject may have experienced both a serious and nonserious event during the study.
Nervous system disorders Ataxia	3.4% 3/89 • 12-week treatment period, and 1-week follow-up period The same event may appear as both an AE and a SAE. However, what is presented are distinct events. An event may be categorized as serious in one subject and as nonserious in another subject, or one subject may have experienced both a serious and nonserious event during the study.
Nervous system disorders Convulsion	3.4% 3/89 • 12-week treatment period, and 1-week follow-up period The same event may appear as both an AE and a SAE. However, what is presented are distinct events. An event may be categorized as serious in one subject and as nonserious in another subject, or one subject may have experienced both a serious and nonserious event during the study.
Nervous system disorders Somnolence	39.3% 35/89 • 12-week treatment period, and 1-week follow-up period The same event may appear as both an AE and a SAE. However, what is presented are distinct events. An event may be categorized as serious in one subject and as nonserious in another subject, or one subject may have experienced both a serious and nonserious event during the study.
Skin and subcutaneous tissue disorders Rash	5.6% 5/89 • 12-week treatment period, and 1-week follow-up period The same event may appear as both an AE and a SAE. However, what is presented are distinct events. An event may be categorized as serious in one subject and as nonserious in another subject, or one subject may have experienced both a serious and nonserious event during the study.

Additional Information

Pfizer ClinicalTrials.gov Call Center

Pfizer, Inc.

Phone: 1-800-718-1021

Email: [email protected]

Results disclosure agreements

Principal investigator is a sponsor employee Pfizer has the right to review disclosures, requesting a delay of less than 60 days. Investigator will postpone single center publications until after disclosure of pooled data (all sites), less than 12 months from study completion/termination at all participating sites. Investigator may not disclose previously undisclosed confidential information other than study results.
Publication restrictions are in place

Restriction type: OTHER