Shares in MannKind Corp fell 16.4% on the news that advisors to the US Food and Drug Administration will meet to review its inhaled insulin Afrezza, which has twice been rejected by the agency.

MannKind notes that the Endocrinologic and Metabolic Drugs Advisory Committee has "tentatively scheduled" a review of Afrezza (insulin human [rDNA origin]) for glycaemic control in adults with type 1 or type 2 diabetes. on April 1. The FDA first rejected the drug in 2010 and turned it down again in 2011.

Hoping for third time lucky, MannKind resubmitted the entire data set of Afrezza, which  included the positive results from two recent Phase II trials designed with guidance from the FDA. The target date for the agency to complete its review of Afrezza is April 15 but this may now be put back because of the committee meeting, the need for which has taken some observers, and indeed MannKind, by surprise.

Simos Simeonidis, an analyst at Cowen & Co, issued a research note saying that if the FDA believes "it makes sense to provide an inhalable insulin (or 'a better insulin,' as is MannKind's view) as an additional tool to physicians to help deal with the "diabetes epidemic," they may want to convene a public panel (ie cover themselves), air out all potential issues of efficacy and safety, before issuing a decision".

He added: "Another bullish argument would be that if FDA did not plan on approving Afrezza, why bother with a panel? Why not just reject the NDA?"