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Experts say proposed label changes or black box warnings would not significantly decrease ADHD drug prescriptions. But they see potential market opportunities for new products and generics.
At a March 22 meeting, FDA’s Pediatric Advisory Committee recommended that the labels for all drugs to treat attention hyperactivity disorder (ADHD) be changed to acknowledge a risk of cardiovascular or psychotic events.
But the committee did not follow in the footsteps of another advisory board, the Drug Safety and Risk Management Committee, which recommended a black box warning for cardiovascular risks to adults be added to the labels of ADHD drugs that are stimulants. The FDA usually follows advisory committee recommendations.
Even if the label changes go forward, industry analysts predict that they would have only a minimal impact on the market for ADHD drugs.
“From a physicians perspective, it isn’t going to change prescribing habits that much,” said Anathea Waitekus, an analyst at market research firm Decision Resources, adding that doctors are very familiar with these drugs because they have been on the market for so long.
Waitekus predicted that parental hesitation due to new labels could have a slight effect on the market. Warnings about an increased suicide risk for teens taking anti-depressants have had little impact on prescribing, she said.
Lisa Kelly, an analyst at Wood Mackenzie, noted that the market share of Adderall XR’s (amphetamine/dextroamphetamine) has not suffered since a warning for people with heart conditions was added to its label in 2004.
Kelly credited her predictions of continued market strength to ADHD drugs’ effectiveness.
“The drugs available to treat ADHD are the most effective of the psychiatric drugs,” Waitekus said.
But Kelly added that there is a market opportunity for an ADHD drug that is not categorized by the Drug Enforcement Agency as an addiction risk. Shire has a product, NRP-104, in development that it believes will not receive a “scheduled” designation.
Lilly’s Strattera (atomoxetine) is the only ADHD treatment that is not designated a controlled substance by DEA. But it also has a warning about suicidal behavior among children in its label.
In a November 2005 report, Waitekus predicted that NRP-104 would achieve blockbuster sales by 2014, driven in large part by the adult market. The next wave of growth in the ADHD market will come from adults, Waitekus said in an interview.
A recent report from pharmacy benefit manager Medco Health Solutions shows that use of ADHD drugs among people age 20 to 44 grew 139 percent between 2000 and 2005. Growth among those 19 and under was 82 percent during the same period.
The company estimates that last year 1.7 million adults and 3.3 million children used ADHD drugs.
But Kelly remains cautious about the adult ADHD market.
The adult ADHD market has only been 5 percent penetrated, compared with 40 percent penetration for the pediatric market, explained Wood Mackenzie analyst Alex Grosvenor. In spite of this, Kelly explained, awareness of ADHD as an adult problem is not very high.
The biggest impact to the ADHD market this year will probably come from generic competition, Kelly predicted. She believes that some form of generic Adderall will be available by the end of 2006.