SILVER SPRING, Md. -- A new type of painkiller that has been trumpeted on Wall Street as potentially the next blockbuster drug is getting a cautious nod from government scientists who say it might be a little easier on patients' stomachs than many of today's pain relievers.
Advisers to the Food and Drug Administration unanimously recommended Tuesday that G.D. Searle be allowed to sell Celebrex, by prescription, to help relieve painful symptoms of arthritis.Thus Celebrex is poised to be the first in a new class of painkillers called "cox-2 inhibitors" to hit the U.S. market. Analysts had predicted that cox-2 inhibitors would be marketed to millions of people as a way to relieve a variety of pains with fewer stomach-plaguing side effects than many popular painkillers.
But the FDA's advisers dampened some of the expectations for Celebrex: They stopped short of recommending the use of the drug for other kinds of pain. And they cautioned that while there are suggestions that Celebrex may be easier on the stomach, few people have taken it long enough to know its long-term safety.
The stock of Monsanto Co., Searle's parent company, fell $1.8125 to $43.50 a share in heavy trading Tuesday.
"I frankly think these drugs are safer," said panel chairman Dr. Steven Abramson of New York's Hospital for Joint Diseases. But, he asked, is there enough proof to let Searle tout the drug as significantly safer? "It's a close call."
The panel said Celebrex doesn't need the standard ulcer warning that comes with other painkillers, but it was stymied on just what warning to give. "Certainly this drug is not ulcer-free," said Dr. Daniel Lovell, a Cincinnati pediatric rheumatologist.
The FDA is not bound by the panel's advice, but typically follows it.
Millions of people now depend on aspirin, ibuprofen, naproxen and a host of other pills called "non-steroidal anti-inflammatory drugs," or NSAIDs. They are used for arthritis, everyday aches, recovery from surgery and myriad other pains. Many are available without prescriptions; others come in higher-dose prescription-only strengths.
But NSAIDs can cause ulcers, stomach bleeding and other gastrointestinal side effects, especially in long-term users. NSAIDs are blamed for causing 107,000 Americans to be hospitalized every year, and for killing 16,500.
In 1990, scientists announced the reason. NSAIDs target an enzyme called cyclo-oxegenase that is responsible for much inflammation accompanying pain. But it turned out there are two types of this enzyme. Cox-2 was behind the inflammation, while cox-1 actually protects the stomach lining. Unfortunately, NSAIDs hit both.
The theory was that if scientists could develop a more specific drug that targeted just cox-2, it would alleviate pain and inflammation while not bothering the stomach. Half a dozen companies began racing to develop a better NSAID.
Searle's Celebrex, known chemically as celecoxib, is the first under FDA scrutiny. In studies of about 13,000 patients, it appeared to work almost as well as prescription-strength naproxen in patients with osteoarthritis. In rheumatoid arthritis sufferers, it appeared to work almost as well as another popular NSAID, diclofenac.
But even if Celebrex isn't as good or better than other painkillers, experts theorized it still would sell if proved safer. So Searle gave 4,700 patients endoscopies -- snaking a tube into their stomachs to see if ulcers were forming even before patients experienced symptoms. Some 25 percent to 40 percent of patients taking ibuprofen or naproxen showed these mini-ulcers, vs. 5 percent to 10 percent of Celebrex patients.
Mini-ulcers can heal on their own, so doctors questioned the relevance of those endoscopy studies. Too few Searle patients went on to experience serious health problems such as gastric bleeding to know if the new drug actually would lower hospitalizations and deaths, some FDA panelists warned.
The new drugs are causing consternation among aspirin and other NSAID makers, who attended the meeting Tuesday en masse to insist their drugs are still good for millions of people. And Merck & Co. is close behind Searle, last week filing an application for the FDA to consider its own cox-2 inhibitor, called Vioxx.