An experimental drug that could probably treat attention deficit hyperactivity disorder (ADHD) among adults is currently undergoing clinical trials in the United States.

The new drug, tentatively called SPN812, has been developed by Supemus Pharmaceuticals and is currently being tested on healthy adults aged between 18 and 64 years who are suffering from some form of ADHD. The trials will evaluate the drug’s safety and tolerability.

As part of the trials, a series of studies will be carried out on 50 patients at five sites across the United States to measure the efficacy of the new drug in reducing ADHD symptoms.

"We are excited to advance our second ADHD portfolio product into Phase II as we make steady progress across all of our pipeline products,” says Jack Khattar, President and CEO of Supernus Pharmaceuticals, in a press statement.

As many as 30 percent of patients suffering from ADHD do not adequately respond to or cannot tolerate the stimulant treatments used to control the symptoms of the disease.

The way SPN812 acts on ADHD patients appears to be promising and could become a novel way of treating patients with attention deficit and hyperactivity disorders. The manufacturers of the drug believe that it represents a strong alternative to existing ADHD regimens in the United States, says Khattar.

SPN812 is one among three compounds being developed by Supernus to treat patients with ADHD. The company is also developing SPN811 as a stimulant ADHD treatment for which the company expects to initiate a Phase II proof-of-concept trial in 2011.

ADHD, though most common among children, can also continue through adolescence and adulthood. Symptoms include difficulty staying focused and paying attention, trouble controlling behavior, and hyperactivity.

The disorder is also estimated to affect 4.4 percent of adults aged between 18 and 44 years in the United States, according to data available with the National Comorbidity Survey Replication. It is estimated that 10 million adults across the United States suffer from ADHD syndrome.