Safety and efficacy of guanfacine extended-release in adults with attention-deficit/hyperactivity disorder: an open-label, long-term, phase 3 extension study

• Published in: BMC psychiatry Vol. 20; no. 1; pp. 485 - 12
• Main Authors: Iwanami, Akira, Saito, Kazuhiko, Fujiwara, Masakazu, Okutsu, Daiki, Ichikawa, Hironobu
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 02.10.2020; BioMed Central; BMC
• Subjects: Adrenergic alpha-2 Receptor Agonists - therapeutic use; Adult; Adults; Attention deficit disorder with hyperactivity; Attention Deficit Disorder with Hyperactivity - drug therapy; Attention deficit hyperactivity disorder; Blood pressure; Bradycardia; Central Nervous System Stimulants - therapeutic use; Clinical trials; Complications and side effects; Constipation; Delayed-Action Preparations - therapeutic use; Dose-Response Relationship, Drug; Double-Blind Method; Drug dosages; Drug use; Executive function; Guanfacine; Guanfacine - adverse effects; Humans; Hyperactivity; Japan; Labels; Medical research; Mental disorders; Patients; Psychiatric Status Rating Scales; Psychiatry; Quality of Life; Rhinopharyngitis; Safety; Thirst; Treatment Outcome; Japan; Attention deficit disorder with hyperactivity; Treatment outcome; Adult; Guanfacine; Safety
• ISSN: 1471-244X; 1471-244X
• DOI: 10.1186/s12888-020-02867-8

To assess the safety and efficacy of long-term administration of guanfacine extended-release (GXR) in adults with attention-deficit/hyperactivity disorder (ADHD). In this open-label, long-term, phase 3 extension study in Japan, 150 patients transitioned from a double-blind trial, and 41 newly enrolled patients received once daily GXR (starting dose 2 mg/day, maintenance dose 4-6 mg/day) for 50 weeks. Primary outcome measures were the frequency and nature of treatment-emergent adverse events (TEAEs); secondary outcome measures included the change from week 0 in ADHD Rating Scale IV with Adult Prompts (ADHD-RS-IV; Japanese version) total and subscale scores, Conners' Adult ADHD Rating Scales (CAARS), Clinical Global Impression-Improvement (CGI-I) and Patient Global Impression-Improvement (PGI-I) scales, and quality of life (QoL) and executive functioning measures. Of all patients, 94.2% (180/191) reported ≥1 TEAE and 19.9% (38/191) discontinued because of a TEAE. Most TEAEs were mild to moderate in severity; there were two serious TEAEs and no deaths. Commonly reported TEAEs (≥10% of patients) were somnolence, thirst, nasopharyngitis, decreased blood pressure, postural dizziness, bradycardia, malaise, constipation, and dizziness. Mean changes from week 0 in ADHD-RS-IV total and subscale scores and CAARS subscale scores were significantly improved in former placebo or GXR patients and new patients at last observation (p < .0001), and the percentage of patients with very much or much improved CGI-I and PGI-I scores increased. There were no major safety concerns during long-term GXR administration in adults with ADHD. After long-term treatment, patients had significant improvements from baseline in ADHD symptoms, QoL, and executive functioning. Japan Primary Registries Network ( https://rctportal.niph.go.jp/en/ ): JapicCTI-163232, registered 04/21/2016.