MannKind Corp said the U.S. Food and Drug Administration extended the review date of its inhaled insulin treatment by three months, sending the company's shares down as much as 22 percent before the bell.
The news comes less than a week after an advisory panel to the FDA recommended approving the treatment, Afrezza, but said longer-term studies would be required to gauge the risk of lung cancer and other potential side-effects.
MannKind said on Monday the new review date of July 15 was set to give the FDA time to fully review information it had submitted.
Analysts had expected the FDA to delay its decision given the concerns about Afrezza's safety and efficacy.
Afrezza consists of a whistle-sized inhaler designed to deliver insulin powder to the lungs, making it more convenient to use than conventional, injected insulin.
If approved, Afrezza would be the first inhaled insulin treatment available in the United States since 2006.
MannKind's shares, which doubled the day after the panel's recommendation, fell as much as 22 percent to $5.36 in premarket trading on Monday.
(Reporting by Vrinda Manocha in Bangalore, Editing by Savio D'Sozua)