Aug. 1 (Bloomberg) -- Schering-Plough Corp.'s drug sugammadex for the reversal of general anesthesia was rejected by U.S. regulators.

Schering-Plough, based in Kenilworth, New Jersey, received a ``not-approvable'' letter from the Food and Drug Administration, the drugmaker said today in a statement. Schering-Plough said it would work with the agency to ``address the issues, which are primarily related to hypersensitivity/allergic reactions.''

The injected drug, also called Bridion, is designed as a safer, faster alternative to older drugs used to reverse anesthesia, providing doctors greater control over sedated patients in millions of surgeries performed each year. An FDA advisory panel unanimously recommended approval of the drug in March, and European regulators approved it earlier this week. In human tests of the drug, one patient suffered a severe allergic reaction.

``We are surprised and disappointed by this action,'' said Thomas P. Koestler, president of Schering-Plough's research institute, in the statement. ``Sugammadex represents the first major pharmaceutical innovation in the field of anesthesia in two decades.''

Schering-Plough acquired Bridion when it bought Akzo Nobel NV's Organon BioSciences unit for $16.1 billion in November. The drug may have peak annual sales of $200 million to $700 million, if approved, analysts said. New products would help Schering- Plough reduce dependence on cholesterol medicines Vytorin and Zetia, which have seen a decline in prescriptions.

FDA Staff

The FDA staff found in a report issued in March that some people receiving Bridion in studies reported hypersensitivity reactions.

``The occurrence of this reaction, even in a relatively small number of subjects, could have a significant impact on the overall finding of safety it is found to be related to Bridion,'' the agency's staff said.

To contact the reporter on this story: Kurt Heine in New York at kheine1@bloomberg.net.

Last Updated: August 1, 2008 08:38 EDT