The Vineland-3 is an instrument that measures communication, daily living skills, socialization, and motor skills for those with intellectual and developmental disabilities. Items consist of open-ended questions related to activities and behavior and are scored as 2 = Usually, 1 = Sometimes, and 0 = Never. Items requiring a binary response are scored as 2 = Yes, 0. V-scale scores for the expressive and receptive communication subdomains range from 1-24; lower scores indicate lower adaptive functioning.

The Vineland-3 is an instrument that measures communication, daily living skills, socialization, and motor skills for those with intellectual and developmental disabilities. Items consist of open-ended questions related to activities and behavior and are scored as 2 = Usually, 1 = Sometimes, and 0 = Never. Items requiring a binary response are scored as 2 = Yes, 0. V-scale scores for the play and leisure time, and interpersonal relationships subdomains range from 1-24; lower scores indicate lower adaptive functioning.

The MSEL are designed for a certified rater to provide an assessment of cognitive ability and motor development of typically developing children from birth through age 68 months. It was administered to all participants in this study irrespective of their chronological age. The instrument consists of 124 items across five scales measuring Gross Motor, Visual Reception, Fine Motor, Expressive Language, and Receptive Language. Each item is scored from 0-5 points with total raw score ranges of 0-100 (gross motor) and 0-78 (fine motor). Lower score indicate lower developmental abilities; higher scores indicate greater developmental abilities.

The MSEL are designed for a certified rater to provide an assessment of cognitive ability and motor development of typically developing children from birth through age 68 months. It was administered to all participants in this study irrespective of their chronological age. The instrument consists of 124 items across five scales measuring Gross Motor, Visual Reception, Fine Motor, Expressive Language, and Receptive Language. Each item is scored from 0-5 points with a total raw score range of 0-50. Lower score indicate lower developmental abilities; higher scores indicate greater developmental abilities.

The MSEL are designed for a certified rater to provide an assessment of cognitive ability and motor development of typically developing children from birth through age 68 months. It was administered to all participants in this study irrespective of their chronological age. The instrument consists of 124 items across five scales measuring Gross Motor, Visual Reception, Fine Motor, Expressive Language, and Receptive Language. Each item is scored from 0-5 points with a total raw score range of 0-50 (expressive language) or 0-48 (receptive language). Lower score indicate lower developmental abilities; higher scores indicate greater developmental abilities.

The Dup15q CGI-S is a 10-domain clinician-rated measure on a 6-point scale that measures global severity of illness at a given point in time. The ten domains are seizures, expressive communication difficulties, fine motor skills difficulties, gross motor skills difficulties, cognitive/intellectual impairment, impairment in activities of daily living/self-care, socialization, maladaptive behavior, sleep difficulties, and overall severity. Response options are 1-none, 2-very mild, 3-mild, 4-moderate, 5-severe, and 6-very severe.

The Dup15q CGI-C is a 10-domain clinician-rated measure on a 7-point scale that assesses the clinician's impression of change in illness compared with baseline. The ten domains are seizures, expressive communication difficulties, fine motor skills difficulties, gross motor skills difficulties, cognitive/intellectual impairment, impairment in activities of daily living/self-care, socialization, maladaptive behavior, sleep difficulties, and overall severity. Response options are 1-very much improved, 2-much improved, 3-minimally improved, 4-no change, 5-minimally worse, 6-much worse, and 7-very much worse. The CGI does not yield a global score.

The ABC-2 is an updated, empirically derived, validated 58-item caregiver-completed rating scale that measures the severity of a range of maladaptive behaviors commonly observed in children, adolescents, and adults with intellectual and developmental disabilities. The Community version of the scale (ABC-2-C) will be used. It is designed for use in individuals who are not residing in institutional settings. The checklist assesses symptoms across five domains: irritability, social withdrawal, stereotypic behavior, hyperactive/noncompliance, and inappropriate speech. Items are scored on a 4-point scale from 0 (never) to 3 (severe problem). The irritability domain score range is 0-45, with higher score indicating greater severity.

The ABC-2 is an updated, empirically derived, validated 58-item caregiver-completed rating scale that measures the severity of a range of maladaptive behaviors commonly observed in children, adolescents, and adults with intellectual and developmental disabilities. The Community version of the scale (ABC-2-C) will be used. It is designed for use in individuals who are not residing in institutional settings. The checklist assesses symptoms across five domains: irritability, social withdrawal, stereotypic behavior, hyperactive/noncompliance, and inappropriate speech. Items are scored on a 4-point scale from 0 (never) to 3 (severe problem). The social withdrawal domain score range is 0-48, with higher scores indicating greater severity.

The ABC-2 is an updated, empirically derived, validated 58-item caregiver-completed rating scale that measures the severity of a range of maladaptive behaviors commonly observed in children, adolescents, and adults with intellectual and developmental disabilities. The Community version of the scale (ABC-2-C) will be used. It is designed for use in individuals who are not residing in institutional settings. The checklist assesses symptoms across five domains: irritability, social withdrawal, stereotypic behavior, hyperactive/noncompliance, and inappropriate speech. Items are scored on a 4-point scale from 0 (never) to 3 (severe problem). The stereotypic behavior subdomain score range is 0-21, with higher scores indicating greater severity.

The ABC-2 is an updated, empirically derived, validated 58-item caregiver-completed rating scale that measures the severity of a range of maladaptive behaviors commonly observed in children, adolescents, and adults with intellectual and developmental disabilities. The Community version of the scale (ABC-2-C) will be used. It is designed for use in individuals who are not residing in institutional settings. The checklist assesses symptoms across five domains: irritability, social withdrawal, stereotypic behavior, hyperactive/noncompliance, and inappropriate speech. Items are scored on a 4-point scale from 0 (never) to 3 (severe problem). The hyperactivity/non-compliance subdomain score range is 0-45, with higher scores indicating greater severity.

The ABC-2 is an updated, empirically derived, validated 58-item caregiver-completed rating scale that measures the severity of a range of maladaptive behaviors commonly observed in children, adolescents, and adults with intellectual and developmental disabilities. The Community version of the scale (ABC-2-C) will be used. It is designed for use in individuals who are not residing in institutional settings. The checklist assesses symptoms across five domains: irritability, social withdrawal, stereotypic behavior, hyperactive/noncompliance, and inappropriate speech. Items are scored on a 4-point scale from 0 (never) to 3 (severe problem). The inappropriate speech subdomain score range is 0-12, with higher scores indicating greater severity.

An adverse event is any untoward medical occurrence in a participant administered a pharmaceutical product and which does not necessarily have to have a causal relationship with the treatment. An adverse event can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding, for example), symptom, or disease temporally associated with the use of a pharmaceutical product, whether or not considered related to the pharmaceutical product. Preexisting conditions which worsen during a study are also considered as adverse events.

This is the average of the EEG parameter 10 x Log_10 of the total beta power between 16 and 32 Hz in microVolt^2.

Total of all reporting groups

Participants were not consented on the collection of race and ethnicity data.

Participants were not consented on the collection of race and ethnicity data.

Part 1: Participants received oral basmisanil BID on the first day of treatment, then TID to Day 365.

Part 2: Participants who completed Part 1 were to receive oral basmisanil for approximately 2 years.

The Vineland-3 is an instrument that measures communication, daily living skills, socialization, and motor skills for those with intellectual and developmental disabilities. Items consist of open-ended questions related to activities and behavior and are scored as 2 = Usually, 1 = Sometimes, and 0 = Never. Items requiring a binary response are scored as 2 = Yes, 0. V-scale scores for the gross and fine motor domains range from 1-24; lower scores indicate lower adaptive functioning.

ITT population: All randomized participants who received ≥1 dose. Participants were allocated to the treatment arm they were randomized to.

The Vineland-3 is an instrument that measures communication, daily living skills, socialization, and motor skills for those with intellectual and developmental disabilities. Items consist of open-ended questions related to activities and behavior and are scored as 2 = Usually, 1 = Sometimes, and 0 = Never. Items requiring a binary response are scored as 2 = Yes, 0. V-scale scores for the expressive and receptive communication subdomains range from 1-24; lower scores indicate lower adaptive functioning.

ITT population: All randomized participants who received ≥1 dose. Participants were allocated to the treatment arm they were randomized to.

The Vineland-3 is an instrument that measures communication, daily living skills, socialization, and motor skills for those with intellectual and developmental disabilities. Items consist of open-ended questions related to activities and behavior and are scored as 2 = Usually, 1 = Sometimes, and 0 = Never. Items requiring a binary response are scored as 2 = Yes, 0. V-scale scores for the play and leisure time, and interpersonal relationships subdomains range from 1-24; lower scores indicate lower adaptive functioning.

ITT population: All randomized participants who received ≥1 dose. Participants were allocated to the treatment arm they were randomized to.

The MSEL are designed for a certified rater to provide an assessment of cognitive ability and motor development of typically developing children from birth through age 68 months. It was administered to all participants in this study irrespective of their chronological age. The instrument consists of 124 items across five scales measuring Gross Motor, Visual Reception, Fine Motor, Expressive Language, and Receptive Language. Each item is scored from 0-5 points with total raw score ranges of 0-100 (gross motor) and 0-78 (fine motor). Lower score indicate lower developmental abilities; higher scores indicate greater developmental abilities.

ITT population: All randomized participants who received ≥1 dose. Participants were allocated to the treatment arm they were randomized to.

The MSEL are designed for a certified rater to provide an assessment of cognitive ability and motor development of typically developing children from birth through age 68 months. It was administered to all participants in this study irrespective of their chronological age. The instrument consists of 124 items across five scales measuring Gross Motor, Visual Reception, Fine Motor, Expressive Language, and Receptive Language. Each item is scored from 0-5 points with a total raw score range of 0-50. Lower score indicate lower developmental abilities; higher scores indicate greater developmental abilities.

ITT population: All randomized participants who received ≥1 dose. Participants were allocated to the treatment arm they were randomized to.

The MSEL are designed for a certified rater to provide an assessment of cognitive ability and motor development of typically developing children from birth through age 68 months. It was administered to all participants in this study irrespective of their chronological age. The instrument consists of 124 items across five scales measuring Gross Motor, Visual Reception, Fine Motor, Expressive Language, and Receptive Language. Each item is scored from 0-5 points with a total raw score range of 0-50 (expressive language) or 0-48 (receptive language). Lower score indicate lower developmental abilities; higher scores indicate greater developmental abilities.

ITT population: All randomized participants who received ≥1 dose. Participants were allocated to the treatment arm they were randomized to.

The Dup15q CGI-S is a 10-domain clinician-rated measure on a 6-point scale that measures global severity of illness at a given point in time. The ten domains are seizures, expressive communication difficulties, fine motor skills difficulties, gross motor skills difficulties, cognitive/intellectual impairment, impairment in activities of daily living/self-care, socialization, maladaptive behavior, sleep difficulties, and overall severity. Response options are 1-none, 2-very mild, 3-mild, 4-moderate, 5-severe, and 6-very severe.

ITT population: All randomized participants who received ≥1 dose. Participants were allocated to the treatment arm they were randomized to.

The Dup15q CGI-C is a 10-domain clinician-rated measure on a 7-point scale that assesses the clinician's impression of change in illness compared with baseline. The ten domains are seizures, expressive communication difficulties, fine motor skills difficulties, gross motor skills difficulties, cognitive/intellectual impairment, impairment in activities of daily living/self-care, socialization, maladaptive behavior, sleep difficulties, and overall severity. Response options are 1-very much improved, 2-much improved, 3-minimally improved, 4-no change, 5-minimally worse, 6-much worse, and 7-very much worse. The CGI does not yield a global score.

ITT population: All randomized participants who received ≥1 dose. Participants were allocated to the treatment arm they were randomized to.

The ABC-2 is an updated, empirically derived, validated 58-item caregiver-completed rating scale that measures the severity of a range of maladaptive behaviors commonly observed in children, adolescents, and adults with intellectual and developmental disabilities. The Community version of the scale (ABC-2-C) will be used. It is designed for use in individuals who are not residing in institutional settings. The checklist assesses symptoms across five domains: irritability, social withdrawal, stereotypic behavior, hyperactive/noncompliance, and inappropriate speech. Items are scored on a 4-point scale from 0 (never) to 3 (severe problem). The irritability domain score range is 0-45, with higher score indicating greater severity.

ITT population: All randomized participants who received ≥1 dose. Participants were allocated to the treatment arm they were randomized to.

The ABC-2 is an updated, empirically derived, validated 58-item caregiver-completed rating scale that measures the severity of a range of maladaptive behaviors commonly observed in children, adolescents, and adults with intellectual and developmental disabilities. The Community version of the scale (ABC-2-C) will be used. It is designed for use in individuals who are not residing in institutional settings. The checklist assesses symptoms across five domains: irritability, social withdrawal, stereotypic behavior, hyperactive/noncompliance, and inappropriate speech. Items are scored on a 4-point scale from 0 (never) to 3 (severe problem). The social withdrawal domain score range is 0-48, with higher scores indicating greater severity.

ITT population: All randomized participants who received ≥1 dose. Participants were allocated to the treatment arm they were randomized to.

The ABC-2 is an updated, empirically derived, validated 58-item caregiver-completed rating scale that measures the severity of a range of maladaptive behaviors commonly observed in children, adolescents, and adults with intellectual and developmental disabilities. The Community version of the scale (ABC-2-C) will be used. It is designed for use in individuals who are not residing in institutional settings. The checklist assesses symptoms across five domains: irritability, social withdrawal, stereotypic behavior, hyperactive/noncompliance, and inappropriate speech. Items are scored on a 4-point scale from 0 (never) to 3 (severe problem). The stereotypic behavior subdomain score range is 0-21, with higher scores indicating greater severity.

ITT population: All randomized participants who received ≥1 dose. Participants were allocated to the treatment arm they were randomized to.

The ABC-2 is an updated, empirically derived, validated 58-item caregiver-completed rating scale that measures the severity of a range of maladaptive behaviors commonly observed in children, adolescents, and adults with intellectual and developmental disabilities. The Community version of the scale (ABC-2-C) will be used. It is designed for use in individuals who are not residing in institutional settings. The checklist assesses symptoms across five domains: irritability, social withdrawal, stereotypic behavior, hyperactive/noncompliance, and inappropriate speech. Items are scored on a 4-point scale from 0 (never) to 3 (severe problem). The hyperactivity/non-compliance subdomain score range is 0-45, with higher scores indicating greater severity.

ITT population: All randomized participants who received ≥1 dose. Participants were allocated to the treatment arm they were randomized to.

The ABC-2 is an updated, empirically derived, validated 58-item caregiver-completed rating scale that measures the severity of a range of maladaptive behaviors commonly observed in children, adolescents, and adults with intellectual and developmental disabilities. The Community version of the scale (ABC-2-C) will be used. It is designed for use in individuals who are not residing in institutional settings. The checklist assesses symptoms across five domains: irritability, social withdrawal, stereotypic behavior, hyperactive/noncompliance, and inappropriate speech. Items are scored on a 4-point scale from 0 (never) to 3 (severe problem). The inappropriate speech subdomain score range is 0-12, with higher scores indicating greater severity.

ITT population: All randomized participants who received ≥1 dose. Participants were allocated to the treatment arm they were randomized to.

An adverse event is any untoward medical occurrence in a participant administered a pharmaceutical product and which does not necessarily have to have a causal relationship with the treatment. An adverse event can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding, for example), symptom, or disease temporally associated with the use of a pharmaceutical product, whether or not considered related to the pharmaceutical product. Preexisting conditions which worsen during a study are also considered as adverse events.

The safety analysis population is the same as the ITT population, assuming treatment is received as assigned at randomization.

The pharmacokinetic (PK) population consisted of all participants who received at least one dose of study treatment and who had data from at least one postdose sample. Only assessment time points with > 1 participant are shown due to concerns that certain demographic characteristics that may be present in only one treatment arm, or the duration a participant was in the trial, present an unacceptable risk of participant re-identification.

The pharmacokinetic (PK) population consisted of all participants who received at least one dose of study treatment and who had data from at least one postdose sample. Only assessment time points with > 1 participant are shown due to concerns that certain demographic characteristics that may be present in only one treatment arm, or the duration a participant was in the trial, present an unacceptable risk of participant re-identification.

This is the average of the EEG parameter 10 x Log_10 of the total beta power between 16 and 32 Hz in microVolt^2.

Part 1: Participants received oral basmisanil BID on the first day of treatment, then TID to Day 365.

Part 2: Participants who completed Part 1 were to receive oral basmisanil for approximately 2 years.