US regulatory officials say they have identified not one but two supposed generic copies of the attention deficit hyperactive disorder (ADHD) treatment drug Concerta that have failed to demonstrate required levels of equivalency.
On 13 November 2014, Irish generic drugmaker Mallinckrodt announced that FDA had determined that its generic version of Concerta (methylphenidate hydrochloride ER tablets) were not therapeutically equivalent to their reference drug.
Under FDA approval standards, all generic products must exhibit—within acceptable tolerances—the same therapeutic effect on a patient as the drug its approval is based upon. As a result of FDA's findings, Mallinckrodt said the agency had announced it would be reclassifying three doses of the company's drug as "therapeutically inequivalent" in its Orange Book—a reference guide of generic drug equivalency classifications.
For more, please see Focus' story, "FDA Says it Discovered Problems With Generic Version of ADHD Drug Concerta."
FDA: Only the Authorized Generic is OK
FDA did not issue its own public statement until later in the day on 13 November 2014, when it revealed that Malinckrodt was not the only manufacturer of methylphenidate hydrochloride ER tablets to exhibit therapeutic equivalence problems during agency testing.
A second drug manufactured by a little-known drug manufacturer, Kudco, was also found to not be therapeutically equivalent to Janssen Pharmaceuticals' Concerta, FDA said in a statement.
"Methylphenidate hydrochloride extended-release products approved as generics for Concerta are intended to release the drug in the body over a period of 10 to 12 hours, FDA explained in a statement. However, "In some individuals, the Mallinckrodt and Kudco products may deliver 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," FDA said.
Only an "authorized generic" version of Concerta manufactured by Actavis was found to be therapeutically equivalent, FDA said.
Both Mallinckrodt and Kudco's drugs are still approved, FDA confirmed, but they are "no longer recommended as automatically substitutable at the pharmacy (or by a pharmacist) for Concerta," the agency said in its statement.
FDA is current evaluating its testing and approval standards to consider if broader changes are needed. The agency has already issued a new bioequivalency standard for methylphenidate hydrochloride products, it said.