To print: Select File and then Print from your browser's menu --------------------------------------------------------------------------------------- Title: Existing Drugs Being Examined as Fibromyalgia Treatment: PAINWeek URL: http://www.pslgroup.com/dg/28775E.htm Doctor's Guide September 11, 2007
By Kristina R. Anderson LAS VEGAS, NV -- September 11, 2007 -- Four new drugs have been undergoing trials for potential use as treatments for fibromyalgia, including one that is better known as the "date rape" drug, a rheumatologist reported here at PAINWeek 2007, the national conference on pain for frontline practitioners. Sodium oxybate (Xyrem®), also known as gamma hydroxybutyrate, which due to safety concerns is currently approved for use only in small populations for the treatment of cataplexy and narcolepsy, is designed to plow users straight from stage 2 sleep into the deeper stage 4 sleep that fibromyalgia patients generally are unable to attain on their own. "Improving stage 4 sleep is a very intriguing idea," said Andrew J. Holman, MD, Assistant Clinical Professor Medicine, University of Washington, and Rheumatologist, Valley Medical Center, Seattle, Washington, United States. Designs for phase 3 trials for sodium oxybate are now underway, he said. Previous trials using liquid dosages of 4.5 g and 6 g indicated a statistically improvement of 20% or greater in a unique composite result that used three factors -- the patients' Pain-Visual Analog Scale, the Fibromyalgia Impact Questionnaire and the Patient Global Impression of Change -- rather than a single ranking. Dr. Holman told the audience that more than 20% of patients in these trials reported an overall improvement of 50%. Also well downstream in the approval pipeline are products that were originally designed for other conditions, including Parkinson's disease, restless leg syndrome and depression, he said. Duloxetine (Cymbalta) primarily targets major depression disorder and has recently been submitted to the Food and Drug Administration for review as a treatment for fibromyalgia. The drug acts on both norepinephrine and serotonin receptors, similar to the old class of tricyclic antidepressants, although data released this summer at the 2007 World Congress on Myofascial Pain Syndrome and Fibromyalgia Syndrome reported improvement in fibromyalgia symptoms in patients with and without depression. Although there was no improvement in the 10 men in that 207-patient study, Dr. Holman predicted that duloxetine would be the next medication to receive FDA approval for fibromyalgia. "I'm confident it is a useful medication and will help people," he said. Another antidepressant in phase 3 trials for fibromyalgia is milnacipran, which inhibits norepinephrine and serotonin reuptake in a 3:1 ratio; the preliminary results of the second phase 3 multicentre trial were announced in May by Forest Pharmaceuticals and Cypress Bioscience, who had enrolled some 1,200 patients with fibromyalgia. They showed significant statistical improvement with symptoms of fibromyalgia and associated pain at dosages of 200 mg compared with placebo. Finally, Pramipexole (Mirapex® and Sifrol®) is currently a medication indicated for treating Parkinson's disease and restless leg syndrome, and is sometimes also used off-label for treatment of certain types of headache. The drug affects the hippocampus and is also seen as aiding users in reaching that highly coveted stage 4 of sleep. Dr. Holman said the drug is appealing for fibromyalgia symptoms due to the relatively low incidence of nausea and dizziness as well as its renal metabolism characteristics. He also pointed out to the audience that Pramipexole led to the loss of 2 to 15 kg (5 to 35 lbs) over 14 weeks in 40% of the test subjects. He called the weight loss an indication that patients with fibromyalgia in general are not exaggerating in describing their oftentimes baffling symptoms to the primary care doctors. "People who tell you they've gained weight are telling the truth," he said. Physicians have in their bag of tricks for fibromyalgia the drug Pregabalin (Lyrica®), which is already approved for this indication. The anticonvulsant commonly used for neuropathic pain is given at doses of 450 mg/day and has produced improved scores in sleep, fatigue and the Patient Global Impression of Change, he said. [Presentation title: Treatment and Management of Pain Associated With Fibromyalgia. ] --------------------------------------------------------------------------------------------- Copyright © 1999 P\S\L Consulting Group Inc. All rights reserved. Republication or redistribution of P\S\L content is expressly prohibited without the prior written consent of P\S\L. 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