Marking a significant milestone in the treatment of Fibromyalgia, a group of scientists led by Dr. Daniel Clauw presented further proof of Milnacipran’s success in treating this chronic pain disorder at the October Annual Meeting of the American College of Rheumatology. Clauw, who is Professor of Medicine in the Division of Rheumatology at University of Michigan, and his colleagues from Cypress Bioscience, Inc. and the Seattle Rheumatology Associates, report significant measures of improvement among patients with Fibromyalgia Syndrome (FMS) who received Milnacipran during Phase II of clinical trials. Cypress Bioscience Inc., who holds the patents for the use of Milnacipran on FMS in the U.S. and Canada, also recently announced that recruitment for Phase III clinical trials will commence in the near future. Currently, although a variety of medications are often employed to alleviate FMS, there is no Food and Drug Administration (FDA) approved drug or combination of drugs available to treat the condition.
Fibromyalgia is a condition affecting approximately 3-8 million Americans, 80-90% of whom are women. Also formerly known as fibrositis, chronic muscle pain syndrome, psychogenic rheumatism, or tension myalgias, this condition is characterized by a chronic fatigue, with widespread pain in a patient’s muscles, ligaments, and tendons. In 1990, the American College of Rheumatology defined the criteria for fibromyalgia as the chronic presence of pain under pressure in 11 of 18 identified sites, such as the upper back, upper chest, back of head, neck, elbows, hips, and knees, among others.
Additionally, a variety of other symptoms often accompany FMS. These may include sleep disruptions (leg muscle spasms, restless leg syndrome or bursts of conscious-level brain activity), irritable bowel syndrome, chronic headaches, facial pain, and heightened sensitivity to various stimuli. Notably, one-third of fibromyalgia sufferers report depression, and temporomandibular joint dysfunction (TMJ) is also a very common complaint. Numbness or tingling in the limbs, dizziness, painful menstrual periods, chest or pelvic pain, and dry skin, mouth and eyes are also typical symptoms.
Traditionally, fibromyalgia would be treated with a variety of medications, such as ibuprofen (Advil), acetametaphine (Tylenol), anti-depressants, or muscle-relaxants, depending on the complaints of the patient. The work of Clauw’s team, however, now suggests that Milnacipran, which acts on the neurotransmitters serotonin and norepinephrine, may be the treatment method of the future. These two neurotransmitters figure prominently in the body’s central control of chronic pain, and are also known to influence mood, emotion, sleep, appetite, and energy levels.
Milnacipran belongs to a class of drugs termed SNRIs, or serotonin norepinephrine reuptake inhibitors. These drugs control the amount of serotonin and norepinephrine available in the body, thus influencing the physiological conditions noted above.
The results compiled by Clauw and his Cypress Bioscience Inc. colleagues indicate great promise for treatment of FMS with Milnacipran. In their Phase II clinical trials, 125 patients received either the drug or a placebo once or twice daily, and recorded pain, fatigue, sleep, and other information throughout the trial.
Notably, 70% of patients receiving Milnacipran indicated significant reductions in pain, compared to only 36% of the control group. Additionally, 37% of the Milnacipran group described a 50% or greater reduction in the intensity of their pain, compared to only 14% of the placebo group. The Milnacipran patients also reported improvements in fatigue level and depressed mood.
Moreover, although doses were escalated for a period of 4 weeks, 84% reached the highest dose level of Milnacipran with no side effects or tolerability issues. For the remaining 16%, the most common side effect was nausea, and adverse reactions were generally mild and temporary.
Cypress Bioscience Inc. expects to initiate enrollment for Phase III of the Milnacipran clinical trials before the end of 2003, with the eventual expectation of submitting a New Drug Application (NDA) to the FDA. As Milnacipran has been commercially available as an anti-depressant in Europe and Asia for over 6 years with no notable safety issues, the future looks very bright for this novel method of treating fibromyalgia.
