FDA Approves Once-Daily ADHD Medication for Adults

On June 20, the U.S. Food and Drug Administration (FDA) approved Shire Pharmaceuticals’ new attention-deficit/hyperactivity disorder (ADHD) medication Mydayis (mixed salts of a single-entity amphetamine product).

Though it contains the same active ingredients as Shire’s existing long-acting drug Adderall XR—the mirror-image chemicals levoamphetamine and dextroamphetamine—Mydayis is formulated to last up to 16 hours instead of 12, making it the first once-daily ADHD medication approved for this extended duration.

In its statement on the approval, Shire stated that Mydayis would be available in the third quarter of this year.

Mydayis consists of these amphetamine salts encased in three drug-releasing beads at a 1:1:1 ratio. One bead is designed for immediate drug release after swallowing, while the other two beads are formulated to dissolve in the stomach and intestines, respectively.

Manisha Madhoo, M.D., Shire’s vice president of global medical affairs for neuroscience, told Psychiatric News that the company looked at multiple options for this new long-term agent but felt that a 16-hour duration was optimal for a once-daily therapy.

And while there are several types of brand name and generic stimulants already approved for ADHD, Madhoo believes that Mydayis fills an important unmet need in the ADHD population.

“Most ADHD medications were initially developed to help children having problems during school, and this new formulation reflects the increased recognition that college-age kids and adults have different schedules,” said Mark Stein, Ph.D., the director of the ADHD Program at Seattle Children’s Hospital.

Stein, who has no connection to the medication, noted that many adults take an extended-release pill in the morning and then a shorter duration medication in the afternoon, but finding the right timing can be difficult. A 16-hour duration simplifies matters.

“With longer benefits also comes the risk that adverse events or drug tolerability lasts longer as well, so clinicians will need to keep an eye on that,” he said.

Madhoo highlighted the age aspect as Mydayis is approved only for adolescents and adults. During the research process, Shire conducted clinical studies in children 12 and younger, but in approval discussions with the FDA, it was decided to limit the drug to patients 13 and up.

The FDA approved Mydayis on the basis of positive data from 16 clinical studies that evaluated more than 1,600 ADHD patients. In placebo-controlled studies, Mydayis significantly outperformed placebo as measured by both the ADHD Rating Scale-IV and the Permanent Product Measure of Performance, an objective, skill-adjusted math test that measures attention.

The most common treatment-related side effects in adults were insomnia, decreased appetite and weight, dry mouth, increased heart rate, and anxiety. In adolescents, the most common reactions were insomnia, decreased appetite and weight, irritability, and nausea. Madhoo said the safety profile is similar to that found in other studies testing stimulants, and no new trends emerged with this extended formulation.

This approval ends a long saga for Shire, which first filed a New Drug Application for Mydayis in 2006 but was instructed by the FDA to conduct additional studies. ■