NEW YORK—Shares of British attention deficit hyperactivity disorder drug maker Shire PLC fell Friday after a Lehman Brothers analyst downgraded the stock, estimating lower sales of Shire's newest drug, Vyvanse.
Kerry Holford downgraded the stock to "Underweight," or "Sell," from "Equal weight." Prescriptions of Vyvanse are growing slowly, Holford said, meaning Shire will lose customers when the patents on its older drug, Adderall XR, expire next year.
Shares declined $1.67, or 3 percent, to $54.69 in morning trading.
Vyvanse will peak at $800 million because prescriptions have been disappointing, Holford said. That estimate is down from a previous expectation of $1.1 billion in sales.
Holford said Vyvanse will have about a 13 percent of the ADHD market by the end of this year. The patents behind Adderall XR will expire next April, and analysts regard the switching of patients to Vyvanse as the biggest issue facing Shire.
The analyst said the increasing price of Adderall will boost Shire's profit in 2008, but after generic competition begins, the weaker sales of Vyvanse will hurt the company.
"We must recognize that whilst 2008 looks set to be windfall, it only makes the earnings decline associated with generic Adderall XR from April 2009, even steeper," Holford wrote.
Goldman Sachs analyst Dani Saurymper downgraded the stock to "Neutral" from "Buy" last week, saying prescriptions of Vyvanse will be weaker than expected because doctors see little difference between Adderall XR and Vyvanse.
