A Phase 4, Multicenter, 2-part Study Composed of a Randomized, Double-blind, Parallel-group, Placebo-controlled, Active-comparator, Dose-optimization Evaluation followed by a Open-label Evaluation to Assess the Safety and Efficacy of Guanfacine Hydrochloride Prolonged-release (SPD503) in Children and Adolescents aged 6 to 17 Years with Attention-deficit/Hyperactivity Disorder

Status

Completed

Phases

Phase 4

Study type

Interventional

Source

EU CTIS

Registry ID

CTIS2022-502630-71-00

Acronym

SPD503-401

Enrollment

Registered

2023-04-25

Start date

2019-11-20

Completion date

2025-09-02

Last updated

2025-07-31

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Attention-deficit/hyperactivity disorder (ADHD)

Brief summary

The primary safety endpoint will be the change from baseline in the CANTAB RTI task.

Detailed description

Secondary safety endpoints: -CANTAB tasks: RVP, SWM between errors, DMS, and SST, Tanner stage, weight, height, BMI, Vital signs (BP and pulse) and ECG results, BPRS-C total score and scales for Depression, Anxiety, Psychomotor Excitation, Behavior Problems, Withdrawal, Thinking Disturbance, and Organicity, C-SSRS, Specified UKU side effect rating scale items: Asthenia/Lassitude/Increased Fatigability, Sleepiness/Sedation, Increased Duration of Sleep, and Orthostatic Dizziness, PDSS, Secondary efficacy endpoints: -ADHD-RS-5 total score and subscale scores for hyperactivity/impulsivity and inattention domains, CGI-I, calculated from CGI-S, CHIP-CE:PRF, C3PS Total Score and scores for Learning Problems and Executive Functioning subscales

Interventions

DRUGIntuniv 3 mg prolonged-release tablets

DRUGIntuniv 4 mg prolonged-release tablets

DRUGIdentical to Intuniv 1mg.

DRUGIntuniv 2 mg prolonged-release tablets

DRUGIdentical to Intuniv 3mg

DRUGATOMOXETINE HYDROCHLORIDE

DRUGIdentical to atomoxetine hydrochloride 10mg

DRUG18mg

DRUG25mg

DRUG40mg and 60mg.

DRUGIdentical to Intuniv 2mg.

DRUGIdentical to Intuniv 4mg.

DRUGIntuniv 1 mg prolonged-release tablets

Eligibility

Sex/Gender

All

Age

0 Years to 17 Years

Design outcomes

Primary

Measure	Time frame
The primary safety endpoint will be the change from baseline in the CANTAB RTI task.	—

Secondary

Measure	Time frame
Secondary safety endpoints: -CANTAB tasks: RVP, SWM between errors, DMS, and SST, Tanner stage, weight, height, BMI, Vital signs (BP and pulse) and ECG results, BPRS-C total score and scales for Depression, Anxiety, Psychomotor Excitation, Behavior Problems, Withdrawal, Thinking Disturbance, and Organicity, C-SSRS, Specified UKU side effect rating scale items: Asthenia/Lassitude/Increased Fatigability, Sleepiness/Sedation, Increased Duration of Sleep, and Orthostatic Dizziness, PDSS, Secondary efficacy endpoints: -ADHD-RS-5 total score and subscale scores for hyperactivity/impulsivity and inattention domains, CGI-I, calculated from CGI-S, CHIP-CE:PRF, C3PS Total Score and scores for Learning Problems and Executive Functioning subscales	—

Measure

Time frame

—

Countries

Belgium, Germany, Netherlands, Spain, Sweden

Outcome results

None listed

Source: EU CTIS · Data processed: Feb 4, 2026