FDA to Mallinckrodt: Generic Concerta doesn't measure up to J&J's brand

The FDA's new due diligence on generic drugs now has one victim: Mallinckrodt, which makes a knockoff version of Johnson & Johnson's ($JNJ) ADHD drug Concerta. The Dublin-based drugmaker says the FDA is questioning whether its generic actually measures up to the brand.

The technical term is "therapeutically equivalent," the standard all generics must meet to win FDA approval. After some testing made possible by new generic drug user fees, the agency now says Mallinckrodt's Concerta copy isn't.

Mallinckrodt CEO Mark Trudeau

Mallinckrodt took issue with that assessment: "We believe that the FDA's actions are not supported by sound scientific evidence and not consistent with the best interests of patients," CEO Mark Trudeau said in a statement. The company's shares fell almost 7% on the news.

For years, the agency had sworn that its premarket testing requirements are solid enough to show that generics work as well as the brands they seek to replace.

But in 2012, the FDA did an about-face on some strengths of generic Wellbutrin XL. After years of complaints, the FDA admitted that the copies weren't therapeutically equivalent, and generics companies--including Teva Pharmaceutical Industries--were forced to pull their products for retesting.

Those Wellbutrin products are back on pharmacy shelves. But the experience prompted FDA to rethink its knee-jerk defense of generic equivalence. The agency started looking into some copycat meds, and after Congress approved the Generic Drug User Fee Act last year, set aside $20 million to expand the effort.

In early 2014, the agency said it would focus first on generic antidepressants, seizure drugs, ADHD meds and immunosuppressants. The agency wouldn't say which particular compounds were under scrutiny at the time. It did say it was reviewing a study of Lipitor generics performed at Brigham & Women's Hospital, which found that some versions of Pfizer's ($PFE) statin were ineffective because of impurities.

Since then, the agency has said it's checking out generic blood pressure drugs, including knockoff versions of AstraZeneca's ($AZN) Toprol XL. That effort began after a Cleveland Clinic cardiologist noticed changes in effectiveness after his patients switched to generics.

The change in status for Mallinckrodt's Concerta version takes it off the "readily substitutable" list, deeming it "presumed to be therapeutically inequivalent." In its statement, the company said that the change was based on new guidelines for Concerta knockoffs, which were published last week.

The company says it "strongly believes" its product is effective and safe. "Based on our review of Mallinckrodt's safety database and the conclusions FDA has shared with the company, we remain confident in the safety of our methylphenidate ER products," Trudeau said.

- see the Mallinckrodt release