(Reuters) - The U.S. Food and Drug Administration has declined to approve an abuse-deterrent version of Mallinckrodt Plc's opioid painkiller Roxicodone, saying some parts of the company's application need further evaluation.
The treatment is a reformulated version of the company's commonly abused painkiller Roxicodone, intended to make the drug less desirable and more difficult to be abused by snorting or injecting.
Mallinckrodt's shares fell 4.4 percent to $20.02 in premarket trading on Wednesday.
The decision comes after an advisory panel to the FDA voted 10-7 in favor of the drug, saying it should be labeled as abuse deterrent only by the nasal route.
"While all the abuse deterrent properties of this medication are perhaps not as robust as we might like, it is an important advance over the existing formulation," Brian Bateman, a panel member who had voted in favor of the drug's approval, had then said.
Mallinckrodt is one of the nation's largest manufacturers of oxycodone - the most commonly abused prescription painkiller after hydrocodone in 2016.
The panel members, during the Nov. 14 meeting, also raised concerns of Mallinckrodt's treatment creating the same problem as Endo International Plc's reformulated Opana ER did.
Endo withdrew the drug from the market last year after postmarketing data showed that while the rates of nasal abuse associated with Opana fell, rates of intravenous abuse rose.
Mallinckrodt, Endo and other drugmakers including Johnson & Johnson have been sued by state and local governments alleging the companies of contributing to the national drug addiction epidemic through their marketing and promotion of opioids.
"We are evaluating the FDA's letter and will request a meeting in the coming weeks to discuss it further," Matt Harbaugh, president of the company's specialty generics unit said in a statement.
(Reporting by Tamara Mathias and Saumya Sibi Joseph in Bengaluru; Editing by Saumyadeb Chakrabarty)