Not all doctors are sure about the pain and fatigue condition known as fibromyalgia, but drug companies are racing to win U.S. regulatory approval to serve this potentially lucrative market.
The sometimes-debilitating disorder afflicts an estimated 2 percent to 4 percent of Americans, mainly women.
But diagnosing fibromyalgia is not easy because its cause remains unknown and its symptoms, which also include depression, can overlap with other conditions.
With no test to confirm fibromyalgia, doctors rely on patient complaints of symptoms and subjective responses to physical exams. As a result, some physicians are wary of viewing it as a distinct ailment.
Still, a who's who of pharmaceutical companies -- including Pfizer Inc., Eli Lilly & Co., Forest Laboratories Inc. and Wyeth -- are looking to seize on a market now dominated by older anti-depressants as well as painkillers and other drugs.
"What they're thinking is: This has a huge, untapped, unmet need," said Maria Marzilli, an associate analyst with market research firm Decision Resources.
Decision Resources expects sales for drugs used for fibromyalgia to roughly triple to at least $1 billion by 2014.
The companies are vying for the first clearance by the U.S. Food and Drug Administration for a fibromyalgia treatment, which could occur as soon as 2008.
Doctors can prescribe medicines for fibromyalgia even though the drugs are not cleared specifically for it. However, without FDA approval, companies cannot promote the drugs as treatments for that condition.