FDA approves guanfacine ER tablets to treat ADHD in children, teens

FDA approved the use of once-daily guanfacine (Intuniv, Shire) extended-release (ER) tablets as adjunctive therapy to stimulants for the treatment of attention deficit hyperactivity disorder (ADHD) in children and adolescents aged 6 to 17 years as part of a total treatment program.

“ADHD can have such a negative impact on a youngster’s life,” Robert Findling, MD, told Formulary. Findling is director of child and adolescent psychiatry at University Hospitals Case Medical Center, Cleveland, and professor of psychiatry and pediatrics at Case Western Reserve University School of Medicine. “Intuniv’s approval for this new indication provides prescribers with a different way to offer help to youths who are still struggling with ADHD-related difficulties despite being treated with a stimulant.”

The approval is based on results from a 9-week placebo-controlled study of Intuniv given in combination with a stimulant to children and adolescents with ADHD. Intuniv is the only once-daily ADHD medication approved for administration as adjunctive therapy to stimulants.

Intuniv, a nonstimulant, is a selective alpha-2A agonist.The effectiveness of Intuniv for more than 9 weeks has not been systematically evaluated.

During the 9-week, multicenter, double-blind, randomized, placebo-controlled study, patients (n=455) experiencing a suboptimal response to stimulant treatment for ADHD received a morning or evening dose of Intuniv (1 mg, 2 mg, 3 mg, or 4 mg) or placebo in combination with their prescribed dose of a stimulant. Clinicians using the ADHD-RS-IV, which includes both hyperactive/impulsive and inattentive subscales, reported significant reductions in total scores from baseline at end point for patients receiving Intuniv and stimulant when Intuniv was dosed either in the morning or evening, compared with placebo and stimulant.

Suboptimal response was defined as treatment with a stable dose of stimulant for at least 4 weeks with improvement, yet persistence of mild-to-moderate ADHD symptoms, in the opinion of the investigator (defined as an ADHD-RS-IV total score of at least 24, Clinical Global Impressions-Severity of Illness scale score of at least 3). Patients with no response to stimulants prior to study enrollment were excluded from participating in this study.

The most commonly observed adverse reactions (incidence greater than or equal to 5% and at least twice the rate for placebo) in this adjunctive trial were somnolence, fatigue, insomnia, dizziness, and abdominal pain. Most such events were mild or moderate in severity and no unique events were observed when Intuniv was given with a stimulant, compared with those reported historically for either treatment alone. Three percent of patients receiving Intuniv plus stimulant left the study because of adverse events, compared to 1% in the placebo plus stimulant group.

Four serious adverse events were reported in the study. They included syncope, mixed disturbance of emotions (similar to behaviors prior to study start), poison ivy, and an unintentional overdose in a sibling of a study participant. All serious adverse events were considered by the investigator to be unrelated to Intuniv.