Science & Technology: MEDICINE
A REVOLUTION IN PAIN RELIEF?
A new class of breakthrough drugs is on the way
Larry E. Stahl had tried just about everything. The 52-year-old retired Chicago truck driver has suffered for years with osteoarthritis, barely able to get out of bed some mornings because of debilitating pain. He's sampled a host of prescription and over-the-counter painkillers but found little relief. Then, two years ago, Stahl signed up to participate in trials of a new painkiller from Merck & Co. The treatment eased the pain and stiffness without upsetting his stomach, as some other medicines had. "I was suffering," he recalls, "and this made a real difference."
The drug is one of a potentially revolutionary new class of painkillers that addresses the agony of the 40 million Americans with arthritis and countless more with other painful ailments. A number of pharmaceutical heavyweights--with Monsanto's G.D. Searle & Co. unit in the lead--are racing to develop their own versions of the new drugs, called COX-2 inhibitors. The first of them could reach the market as early as 1999. A recent report from Morgan Stanley, Dean Witter Equity Research figures COX-2 sales of the Searle and Merck drugs could hit $5 billion five years after they are launched. And revenue could go higher if research into their use against Alzheimer's and cancer proves successful. "This class has `breakthrough' written all over it," says Stephen S. Tang, national director of A.T. Kearney Inc.'s pharmaceutical consulting practice.
The COX-2 inhibitors have a big advantage over existing pain treatments: They are far less likely to produce the serious stomach disorders that cause 16,500 deaths and 107,000 hospitalizations in the U.S. every year. That could give them a critical edge over aspirin, Advil, and such prescription drugs as SmithKline Beecham's Relafen and American Home Products' Lodine XL. Analysts say the new drugs could largely displace the existing prescription products, which now generate $2 billion in annual sales, according to market research firm IMS America Ltd. SmithKline and American Home say their products have excellent safety records and that it is too early to speculate on the impact of the COX-2 drugs on their business. But Dr. Thomas J. Schnitzer, who is running clinical trials of Merck's and Searle's COX-2 drugs at Northwestern University, says, "I think the existing prescription nonsteroidal anti-inflammatory drugs will be wiped out."UPSET STOMACHS. The search for COX-2 drugs grew out of a new understanding of how pain signals are received. Scientists had long believed that so-called nonsteroidal anti-inflammatory drugs, or NSAIDs--the class that includes aspirin, Advil, Aleve, and others--work by blocking the action of a single enzyme called cyclooxygenase, or COX. The COX enzyme produces messengers, called prostaglandins, that talk to cells, triggering pain and swelling when prompted by injury to the joints. By inhibiting the action of the COX enzyme, the nonsteroidal drugs reduce pain and inflammation.
But in the early 1990s, researchers realized that the pain mechanism isn't all that simple. Scientists had found there are actually two COX enzymes. COX-1 is present all the time and has other functions, such as helping to maintain the lining of the stomach. But COX-2 seems to rear up most often at the site of pain and inflammation. Current anti-inflammatory drugs inhibit both enzymes, relieving pain but sometimes causing stomach irritation and bleeding. With the discovery of COX-2, researchers raced to find compounds that would leave COX-1, and the stomach, virtually untouched.
For Searle and Merck, the stakes couldn't be higher. Between 2000 and 2005, Merck will see patents expire on a handful of big drugs that represent $5 billion in U.S. sales. Competition from generic versions will rapidly erode sales, so Merck needs a steady stream of new products to maintain its double-digit growth rate. For Searle, a longtime also-ran in the drug industry, its COX-2 drug comes just as the company's fortunes are beginning to turn. Searle's president of research and development, Philip Needleman, is one of the first scientists to discover COX-2 and has led what he calls "a full-court press" to bring the drug to market. "This could transform the whole company," he says.BRAWL. Early clinical testing for Merck and Searle was promising. Now, Searle is in the final phase of human trials of the drug for use in treating osteoarthritis and rheumatoid arthritis. Merck is finishing its own trials for the treatment of osteoarthritis and pain, with trials still under way for the drug's use in rheumatoid arthritis. Searle hopes to file for marketing approval with the Food & Drug Administration in the second half of this year, and Merck is expected to file by yearend.
But the COX-2 inhibitors may be helpful against more lethal diseases than arthritis. A study just published in the medical journal Cancer Research reports that the compound suppressed the incidence of colon tumors in mice injected with cancer cells by 93%. Other studies have found that brain tissues of patients with Alzheimer's disease often have elevated levels of COX-2. The role of COX-2 in these diseases is not understood, but scientists theorize that inflammation stimulated by the enzyme may be a contributor to the development of both illnesses.
That sort of promise is fueling a behind-the-scenes brawl between Merck and Searle. Last year, Searle argued to the U.S. Patent & Trademark Office (PTO) that Merck's COX-2 drug is part of a class of compounds for which Searle should have patent protection. Merck General Counsel Mary M. McDonald says the company is confident the patent on its COX-2 drug will not overlap with Searle's patent rights, but it may take years for the patent fight to work its way through the PTO and the courts.
The fight for market share will be far more immediate. If the drugs are launched in 1999 as expected, Searle and Merck will be sure to mount massive marketing blitzes. It won't be a hard sell, though, to chronic pain victims like Larry Stahl.By Amy Barrett in Rahway, N.J., and Richard A. Melcher in Skokie, Ill.Return to top