Pfizer, Sanofi-Aventis, and Nektar Therapeutics, developers of the system, were notified last Friday that the FDA wanted to conduct an extended review of their "technical chemistry data".
For Pfizer and Sanofi-Aventis press release:
Pfizer and Sanofi-Aventis Statement on Status of Exubera
For a news summary:
FDA Delays Decision on Inhalable Insulin