Shire announces publication of open-label study on coadministration of INTUNIV with stimulants

November 16th, 2009

November 16, 2009 - Shire plc (LSE: SHP, NASDAQ: SHPGY), the global specialty biopharmaceutical company, announced new study results on INTUNIV™ (guanfacine) Extended-Release Tablets published in the October Journal of Child and Adolescent Psychopharmacology. In this open-label safety study, there was no evidence of unique adverse effects with the combination of INTUNIV and amphetamine or methylphenidate relative to what was observed with either medication alone. The open-label study also assessed improvement of Attention-Deficit/Hyperactivity Disorder (ADHD) symptoms using the ADHD Rating Scale-IV (ADHD-RS-IV). INTUNIV is a nonscheduled, once-daily selective alpha-2A agonist indicated for monotherapy treatment of ADHD in children and adolescents ages 6 to 17.

"Pivotal studies have shown that INTUNIV improved ADHD symptoms in children and adolescents with the disorder, and the publication of these safety data gives us insight into administering INTUNIV in combination with stimulant medications in the management of ADHD," said Andrew J Cutler, MD, courtesy assistant professor, department of psychiatry, University of Florida, and CEO and medical director, Florida Clinical Research Center, Bradenton, FL. "This study helped inform the design of a controlled coadministration trial of INTUNIV with stimulant medications, which Shire is currently conducting."

An estimated 25 to 30 percent of ADHD patients may not respond to the most commonly prescribed ADHD medications, methylphenidates and amphetamines, when used alone as ADHD treatment.

This nine-week, open-label, multicenter, dose-escalation study assessed the safety and effectiveness of coadministering INTUNIV with stimulant medications (methylphenidate or amphetamine). The enrolled patient population included 75 children and adolescents ages 6 to 17 diagnosed with ADHD whose ADHD symptoms were suboptimally controlled after at least one month of treatment with these stimulants. Investigators then started subjects at 1 mg/day of INTUNIV and increased the dose each week by 1 mg to the highest tolerated dose (1 mg/day, 2 mg/day, 3 mg/day, or 4 mg/day). Throughout the INTUNIV titration and maintenance phases of the study, subjects remained on the current dose of their stimulant medication.

The study met its primary objective which was to evaluate the safety of coadministration of INTUNIV (up to 4 mg/day) with stimulants. The study safety assessments included adverse events (AEs), vital signs, electrocardiogram (ECG) readings, physical examination, clinical laboratory tests, the Pediatric Daytime Sleepiness Scale (PDSS), and the Pittsburgh Side Effects Rating Scale (PSERS). AEs were generally mild to moderate. The most common treatment-emergent AEs seen with coadministration (>10.0 percent) were fatigue (34.7 percent), headache (33.3 percent), upper abdominal pain (32.0 percent), irritability (32.0 percent), somnolence (18.7 percent), and insomnia (16.0 percent). The most common treatment-emergent AEs that investigators deemed were possibly related or related to INTUNIV when given with either stimulant were upper abdominal pain (25.3 percent), fatigue (24.0 percent), irritability (22.7 percent), headache (20.0 percent), somnolence (18.7 percent), and insomnia (13.3 percent). Similar proportions of both treatment groups (INTUNIV and amphetamine or INTUNIV and methylphenidate) experienced these treatment-emergent AEs. Blood pressure decreases, though frequent, were rarely rated by investigators as AEs: two subjects (2.7 percent) had decreased blood pressure and one (1.3 percent) had unspecified hypotension. There were no serious AEs or deaths.

Furthermore, coadministration of INTUNIV with methylphenidate or amphetamine did not increase sleepiness, as noted by the decrease in PDSS scores assessed at visit six and at the end of the study.

Study results also demonstrated statistically significant mean changes from baseline (stimulant monotherapy just prior to receiving INTUNIV) to end point in ADHD-RS-IV total scores. Secondary efficacy end points included subjects' scores on the Conners' Parent Rating Scale-Revised Short Form (CPRS-R), Clinical Global Impression-Severity and Improvement scales (CGI-S and CGI-I), Parent Global Assessment (PGA) scale, and Child-Health Questionnaire-Parent Form (CHQ-PF50).

INTUNIV is not approved for coadministration with other ADHD medications.

Source: Porter Novelli