An Anesthesia Revolution?

Some anesthesiologists are already touting an experimental drug, sugammadex, as a groundbreaking game-changer in how they awaken patients after surgery. Will a panel of experts be as enthusiastic when they meet Tuesday to help the Food and Drug Administration decide whether to approve the drug?

Sugammadex was one of the key factors in Schering-Plough (nyse: SGP - news - people )'s $15 billion purchase of Dutch pharmaceutical firm Organon. Its prospects are one of the main near-term reasons to invest in Schering-Plough, although these "pros" must be balanced against the effects of the controversy over the cholesterol drugs Vytorin and Zetia, which are sold in a joint venture with Merck (nyse: MRK - news - people ). (See: "Waiting For Enhance.")

The journal Anesthesia & Analgesia devoted its entire April 2007 issue to sugammadex, and researchers were almost breathless about its promise. "Sugammadex is clearly one of the most exciting drugs to appear in the field of anesthesia in many years," wrote Ronald D. Miller, an anesthesiologist at the University of California, San Francisco, in one editorial. Mohamed Naguib of M.D. Anderson Cancer Center called sugammadex a "revolutionary" medicine that "may change the face of neuromuscular pharmacology."

For sensitive operations like spine, heart or brain surgery, doctors don't just put patients to sleep, they temporarily paralyze them with powerful muscle relaxants. The same relaxants are often used when inserting a breathing tube. Reversing that paralysis so patients can breathe again requires using other drugs that hog the same cellular receptors the muscle relaxants hit. (For more, see: "The Reviver.") But the drugs used to wake patients up have their own cardiovascular and other side effects.

More importantly, they don't always work that well. If a patient needed a big dose of muscle relaxant, it can mean more time on a ventilator as those drugs wear off. A faster-acting, more potent and safer drug could bring a windfall for Schering, and analysts have been getting excited about sugammadex, which will be known by the trade name Bridion if it is approved.

Instead of targeting the receptors the muscle relaxants hit, sugammadex is a big carbohydrate molecule that binds to the muscle relaxant itself. To accomplish this unique approach, Organon chemist Anton Bom came up with a molecule that resembles a hungry octopus, with eight chemical "arms" that can grab the muscle relaxant and trap it in a maw-like hole.

Because it is made of sugars, sugammadex should not cause side effects by tripping receptors unexpectedly. But in briefing documents released March 7, FDA staffers raised several concerns.

The most serious concern involves relatively rare allergic reactions. Schering-Plough is expected to present new safety data to address this on Tuesday. Investors should pay close attention, because this is the main risk that could tilt the balance of how sugammadex is used.

Other concerns noted by FDA staff are the drug's effect on the skeletal system (probably not a major concern for a medicine designed for one-time use) and on children's teeth (the staffers say there isn't enough data to know if problems seen in rats' teeth during the trial will extend to kids.) The FDA staff also raised questions about how the study measured clinical effectiveness, although anesthesiologists do seem generally impressed with the drug.

There's been speculation that sugammadex, though expensive, will actually save hospitals money. Mark Schlesinger, chairman of anesthesiology at Hackensack Medical Center, said in an interview earlier this year that he doubts the drug will save hospitals that much, but he expects to use it anyway because it appears to be safer and more effective than alternatives.

Another potential issue: Most of the studies with sugammadex have been done with Zemeuron, a muscle relaxant also made by Organon. It's possible that doctors will use it with other drugs of the same type, so the FDA may want more studies on the combination of sugammadex with other muscle relaxants.

One big issue for Schering is that advances in anesthesiology are few and far between; it's far easier for Wall Street to gauge the potential of a new cardiovascular drug than of a new anesthetic. So far, sugammadex has looked like a winner. The reaction of the FDA's expert panel will go a long way toward determining whether this bet actually pays off for Schering-Plough.