WASHINGTON (Reuters) - Shire Plc SHP.L has agreed to a U.S. Food and Drug Administration request to study its stimulant Vyvanse in preschool children as concern rises over the diagnosis and treatment of attention deficit hyperactivity disorder, the drugmaker said on Thursday.
A report last year by the Centers for Disease Control and Prevention found that the number of children diagnosed with ADHD increased 41 percent from 2003 to 2011 and that 6.4 million children, or 11 percent of those aged 4 to 17, have been diagnosed with that condition.
Drugs treatments include Ritalin, Adderall and Vyvanse. Only Adderall, which is also made by Shire, is approved to treat children under the age of 6. Yet children much younger are taking the drugs and the FDA wants additional information to ensure they are safe in this very young population.
Gwen Fisher, a spokeswoman for U.K.-based Shire, said the company is designing three clinical trials for children aged 4 to 5. One will examine how the body absorbs, breaks down and excretes drugs. Another will test for safety and efficacy. A third will test for safety over a longer period.
The company said it expects to launch the trials in the first half of 2015.
ADHD patients have difficulty paying attention and may have poor impulse control. Most drugs that treat the condition are potentially addictive stimulants which, paradoxically, can help organize thoughts and calm behavior.
But the drugs have been associated with growth suppression in children and they can also cause hallucinations, mania and delusions.
Very little research has been done on the effect of stimulants in children. A search by researchers from the Mario Negri Institute for Pharmacological Research in Milan, Italy, found just six studies that monitored a total of 3,000 children for side effects for at least 12 weeks.
Worldwide sales of Vyvanse grew 18 percent in the first quarter to $351 million.
(Reporting by Susan Heavey in Washington and Paul Sandle in London; editing by Sarah Young and Richard Chang)