Adults 6 to 17, any sex, with Attention Deficit Disorder With Hyperactivity. Patients with the condition only — healthy volunteers not accepted.
Results — posted to ClinicalTrials.gov
Per-arm endpoint measurements with 95% confidence intervals where reported. Source: trial results section.
Change From Baseline in Choice Reaction Time (CRT) at 6 WeeksPrimary· Baseline and 6 weeks
Choice reaction time (CRT) is a computerized assessment that trains the subject in holding down a press-pad and releasing the press-pad in response to stimuli presented on the screen. The task requires the subject to react as soon as a yellow dot appears in one of five locations, and the subject must respond by lifting their hand from the press-pad. This is the reaction time (RT) and ranges from 100 to 5000 msec. Lower scores indicate better performance.
Group
Value
95% CI
SPD503
20.7
± 63.11
Placebo
21.9
± 64.04
Change From Baseline in Digital Symbol Substitution Task/Coding Test (DSST/Coding) Scores at 6 Weeks in Age Category 8-17 YearsSecondary· Baseline and 6 weeks
The Digital Symbol Substitution Task/Coding Test (DSST/Coding) assesses relative contributions of speed, memory, and visual scanning. Subjects are required to copy symbols that are paired with simple geometric shapes or numbers within a specific time. Scores range from 0-65 in age category 6-7 years and 0-199 in age category 8-17 years. Higher scores indicate better performance.
Group
Value
95% CI
SPD503
18.3
± 14.03
Placebo
20.7
± 17.18
Change From Baseline in DSST/Coding Scores at 6 Weeks in Age Category 6-7 YearsSecondary· Baseline and 6 weeks
The Digital Symbol Substitution Task/Coding Test (DSST/Coding) assesses relative contributions of speed, memory, and visual scanning. Subjects are required to copy symbols that are paired with simple geometric shapes or numbers within a specific time. Scores range from 0-65 in age category 6-7 years and 0-199 in age category 8-17 years. Higher scores indicate better performance.
Group
Value
95% CI
SPD503
1.9
± 1.95
Placebo
9.7
± 0
Change From Baseline in Spatial Working Memory (SWM) Scores at 6 WeeksSecondary· Baseline and 6 weeks
The Spatial Working Memory (SWM) Test is a computerized assessment of working memory and strategy performance. The subject is required to find blue "tokens" in various displayed boxes and use the "tokens" to fill a column on the right side of the screen. Subjects can only find "tokens" in new boxes, therefore they must remember where previous "tokens" were found. SWM scores including number of between errors, number of within errors, and number of double errors range 0-800 and SWM strategy scores range 8-56. Lower scores indicate better performance.
Between errors
Group
Value
95% CI
SPD503
-4.4
± 7.42
Placebo
-3.2
± 6.75
Within errors
Group
Value
95% CI
SPD503
0.0
± 1.11
Placebo
-0.1
± 0.73
Double errors
Group
Value
95% CI
SPD503
-0.0
± 0.69
Placebo
0.1
± 0.53
Strategy
Group
Value
95% CI
SPD503
-0.9
± 2.74
Placebo
-0.1
± 2.56
Change From Baseline in Attention Deficit Hyperactivity Disorder Rating Scale (ADHD-RS-IV) Total Score at 6 WeeksSecondary· Baseline and 6 weeks
Change in the Attention Deficit Hyperactivity Disorder Rating Scale-fourth edition (ADHD-RS-IV) total score from baseline. The ADHD-RS-IV consists of 18 items scored on a 4-point scale ranging from 0 (no symptoms) to 3 (severe symptoms) with total score ranging from 0 to 54.
Group
Value
95% CI
SPD503
-8.8
± 5.98
Placebo
-5.5
± 7.23
Number of Participants With Improvement in Clinical Global Impression-Improvement (CGI-I) at 6 WeeksSecondary· 6 weeks
Clinical Global Impression-Improvement (CGI-I) consists of a 7-point scale ranging from 1 (very much improved) to 7 (very much worse). Improvement is defined as a score of 1 (very much improved) or 2 (much improved) on the scale.
Group
Value
95% CI
SPD503
67
Placebo
20
Change From Baseline in Pediatric Daytime Sleepiness Scale (PDSS) Scores at 6 WeeksSecondary· Baseline and 6 weeks
The Pediatric Daytime Sleepiness Scale (PDSS) is an 8 question questionnaire scored on a scale from 0 (never) to 4 (always). Total scores range from 0 to 32, with increasing score reflecting greater sleepiness.
Group
Value
95% CI
SPD503
-1.3
± 5.36
Placebo
0.9
± 5.31
Change From Baseline in Pictorial Sleepiness Scale (PSS) Scores at 6 WeeksSecondary· Baseline and 6 weeks
The Pictorial Sleepiness Scale (PSS) scores range from 1 (far left wide awake face) to 5 (far right very sleepy face). Increasing score reflects greater sleepiness.
Group
Value
95% CI
SPD503
0.0
± 0.61
Placebo
0.1
± 0.63
Adverse events — posted to ClinicalTrials.gov
Reporting threshold: 2%.
Adverse-event reports describe events observed during the trial — not all are caused by the drug.
The purpose of this study is to determine the effects of SPD503 compared to placebo on tasks of sustained attention in children and adolescents aged 6-17 diagnosed with ADHD.
Publications & conference data
1 peer-reviewed publication reference this trial (live from Europe PMC):
Publications: Europe PMC API search by NCT ID, retrieved 10 June 2026
Drug + disease cross-links: matched in real time against Drug Landscape's normalised drug + company + condition tables
Sponsor: as reported to ClinicalTrials.gov by Shire
Last refreshed: 10 June 2021
Drug Landscape aggregates and links these public records for informational use only. Always verify against the primary source before clinical or regulatory decisions. Canonical URL: https://druglandscape.com/trial/NCT00150592.