Pfizer drug gets U.S. approval to treat fibromyalgia

WASHINGTON (Reuters) - Pfizer Inc. won U.S. approval on Thursday to promote its prescription drug Lyrica for treating fibromyalgia, a chronic disease which can cause debilitating pain, sleep problems, stiffness and fatigue.

The medicine is the first treatment approved by the U.S. Food and Drug Administration for fibromyalgia, which affects about 3 million to 6 million people in the United States each year, mostly women, the FDA said.

Pfizer already sells Lyrica for treating neuropathic pain, a type of pain arising from the nerves without any obvious cause, and epileptic seizures.

The approval "provides a reason for optimism for the many patients who will receive pain relief with Lyrica," said Dr. Steven Galson, director of FDA's Center for Drug Evaluation and Research, in a statement.

"However, consumers should understand that some patients did not experience benefit in clinical trials. We still have more progress to make for treatment of this disorder," Galson said.

Promotion of the drug for fibromyalgia is expected to boost sales of Lyrica.

First-quarter Lyrica sales more than doubled to $395 million, Pfizer reported in April. The drug has been prescribed to more than 5 million people worldwide. Its generic name is pregabalin.

The cause of fibromyalgia is unknown, and no test exists to confirm a diagnosis. Doctors rely on patient complaints of symptoms and subjective responses to physical exams.

Patients may try dietary changes or exercise, or antidepressants, pain relievers and other medicines to ease symptoms.

Fibromyalgia patients experience pain differently than others, and are thought to be more sensitive to stimuli that are not normally painful.

The exact way that that Lyrica reduces pain is unknown, the FDA and Pfizer said. The drug is thought to calm damaged nerves that may be overactive in fibromyalgia, the company said.

One Pfizer study evaluated 745 patients who took either Lyrica or a placebo, and found more Lyrica patients reported pain reduction by at least 50 percent over 14 weeks.

Twenty-seven percent of patients who took a 450-milligram daily dose said their pain was cut by half or more, compared with 15 percent who got a placebo.

The FDA approved doses of 300- and 450-milligrams per day but declined to clear the highest dose of 600 milligrams.

Lyrica's most common side effects in clinical trials included mild-to-moderate dizziness and sleepiness. Patients also reported blurred vision, weight gain, dry mouth, and swelling of the hands and feet.

The drug also may impair motor function and cause problems with concentration and attention, the FDA said. Patients should ask their doctor if Lyrica may impair driving ability, the agency advised.

A 30-day supply of Lyrica costs about $130 at some retailers, a Pfizer spokesman said.

Several other companies, including Eli Lilly and Co., Forest Laboratories Inc. and Wyeth, also are studying fibromyalgia treatments.

Pfizer shares gained 21 cents, or 0.8 percent, to close at $25.92 on the New York Stock Exchange.