(Reuters) - Impax Laboratories Inc said U.S. health regulators raised fresh concerns related to manufacturing practices at the drugmaker's Hayward, California facility, sending its shares down more than 20 percent after the bell.
The company's hopes of securing an approval for its Parkinson's drug Rytari are tied to its ability to resolve issues at the plant, where the drug is partly manufactured.
The U.S. Food and Drug Administration completed its re-inspection of the Hayward facility and in a report outlined 12 "observations", three of which had already been pointed in earlier communications, Impax said on Monday.
The regulator typically outlines observations from conditions that may constitute violations of standard manufacturing practices.
The FDA had rejected approval to Rytary in January, pending a satisfactory re-inspection of the Hayward facility.
However, Impax executives on a conference call said that none of the FDA observations disclosed on Monday impacted the study data related to Rytary, which the company plans to launch in the first half of 2014.
Impax intends to formally request the FDA that Rytary approval be separated from the warning letter considerations for the facility.
"We have committed significant resources in our efforts to meet FDA requirements and are clearly disappointed by this news," Impax Chief Executive Larry Hsu said in a statement.
Impax backed its forecast for 2013, but did not factor in remediation costs that could be involved with the new concerns highlighted in the FDA report.
The FDA first expressed concerns related to the facility in a warning letter in June 2011. Impax has since transferred manufacturing of some of its marketed products to its facility in Taiwan.
But the company continues to manufacture some other products at the Hayward plant and said shifting those products it is developing would be difficult, as they would require pre-approval inspection by the FDA before they are transferred.
On Monday, Impax said the FDA did not inform on the impact the new concerns would have on resolving the warning letter, or if the agency planned to take further regulatory action.
Impax plans to respond to the FDA's new observations within 15 business days.
The company's shares, which were halted pending the release of its statement, fell about 21 percent to $15.80 in after-market trading on Monday afternoon.
(Reporting By Vrinda Manocha in Bangalore; Editing by Saumyadeb Chakrabarty, Bernard Orr)