Searle's (Skokie, IL) COX-2 inhibitor, Celebrex, a nonsteroidal anti-inflammatory drug (NSAID), was linked to 10 deaths and 11 gastrointestinal hemorrhages in the three months following approval in January for use in rheumatoid arthritis. Within a week of filing a quarterly adverse-effects report with the FDA in April, Searle saw sales of Celebrex, which had already racked up 2.5 million prescriptions, plunge sharply. Around the same time, an FDA advisory committee recommended approval of Merck's (Whitehouse Station, NJ) COX-2 inhibitor, Vioxx, for osteoarthritis and acute pain, escalating an NSAID war between Searle and Merck. "A cause–effect connection between the deaths and hemorrhages cannot be confirmed," says Peter Isakson, executive director of COX-2 development at Searle. And with so many prescriptions of Celebrex issued, analysts say they would have expected more adverse-effect reports. Meanwhile, Merck's application for wider indications has led analysts to speculate that, despite its three-month handicap, sales of Vioxx could overtake those of Celebrex.