FDA Questions Equivalence of Generic ADHD Medications
Two approved generic versions of methylphenidate hydrochloride extended-release tablets used to treat attention deficit hyperactivity disorder (ADHD) may not be therapeutically equivalent to Concerta, the brand-name drug, according to an FDA statement expressing concern.
Mallinckrodt Pharmaceuticals and Kudco Ireland Ltd manufacture the two approved generic versions questioned by the FDA, while Janssen Pharmaceuticals, Inc makes the brand-name drug and an authorized generic marketed by Actavis under a licensing agreement.
The FDA’s concerns are based on an internal re-examination of previously submitted data and on FDA laboratory tests of the products. The analysis included the generic products by Mallinckrodt, Kudco, and Actavis. The Actavis product was found to be bioequivalent to Concerta in the analysis.
All the methylphenidate hydrochloride extended-release tablets approved as generics for Concerta are intended to release the drug over a 10 to 12 hour period, which makes possible a single-dose product that delivers the same effect of a three times per day dose of the immediate-release version.
However, the FDA stated that “in some individuals, the Mallinckrodt and Kudco products may deliver the drug in the body at a slower rate during the 7 to 12 hour range. The diminished release rate may result in patients not having the desired effect.”
Due to these findings, the FDA changed the therapeutic equivalence rating for the Mallinckrodt and Kudco generics from AB to BX, which means that the drugs are still approved for prescription but are no longer recommended as automatically substitutable at the pharmacy for Concerta.
The FDA requested that the companies confirm the bioequivalence of their products within six months or voluntarily withdraw them from the market.
Mallinckrodt responded to the FDA and disagreed with the reclassification, saying it “strongly believes its methylphenidate ER products are safe and effective when used in accordance with the approved labels.”
“We believe that the FDA’s actions are not supported by sound scientific evidence and are not consistent with the best interests of patients,” Mark Trudeau, President and CEO of Mallinckrodt said in a statement. According to the company, the products have consistently met the quality specifications and regulatory requirements originally defined by the FDA and the company has received only 68 confirmed reports of adverse events related to a lack of efficacy since the product’s launch 21 months ago.
Mr. Trudeau added, "We have expressed to the FDA our earnest desire to have a robust scientific dialogue about these important issues, and it is our hope that this dialogue will take place soon.”
—Lauren LeBano
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