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FDA Approves Duloxetine HCl for the Management of Fibromyalgia
"The approval of Cymbalta is important because it provides physicians and patients with a new treatment option shown to help reduce pain and improve functioning in this difficult-to-treat disorder," said Madelaine Wohlreich, M.D., medical advisor and research physician at Lilly.
The cause of fibromyalgia remains unknown; however, scientists believe it may be related to some combination of changes in brain and spinal cord chemistry,(i) genetics(ii) and stress(iii). Some researchers believe fibromyalgia is a disorder of increased sensitivity to pain. Although the way Cymbalta works in people is not fully known, medical experts believe it increases the activity of two naturally occurring substances called serotonin and norepinephrine. These substances aid communication in many areas of the brain and spinal cord that affect emotion. Research also suggests that these substances are part of the body's natural pain-suppressing system.
"The FDA approval of Cymbalta for the management of fibromyalgia is another important step in the efforts to ensure that people with fibromyalgia will have the availability of effective medications to help reduce the chronic, widespread pain of this life-altering disorder," said Lynne Matallana, president of the National Fibromyalgia Association and a fibromyalgia patient.
Fibromyalgia is estimated to affect 2 percent of the U.S. population - approximately 5 million people - the majority of those diagnosed being women.(iv),(v) The disorder is characterized by chronic widespread pain and tenderness. Some patients may have additional symptoms.(i) Although there is no known cure for fibromyalgia, some physicians recommend a comprehensive care plan that can include education, medication, and lifestyle changes to help manage the symptoms of the disorder.(i)
"In fibromyalgia, there is no one-size-fits-all approach to managing the disorder," said Dan Clauw, M.D., professor of medicine in the University of Michigan's Division of Rheumatology and director of the Chronic Pain and Fatigue Research Center at the University of Michigan.
The approval marks the fourth disorder that the FDA has approved for Cymbalta. In addition to fibromyalgia, Cymbalta is approved for the management of diabetic peripheral neuropathic pain (DPNP) and the treatment of major depressive disorder and generalized anxiety disorder, all in adults age 18 years and older.
Additional important changes have been made to the Cymbalta prescribing information, including updates to the Warnings and Precautions section. Full prescribing information can be found at www.cymbalta.com.
Lilly established the efficacy of Cymbalta in two pivotal three-month clinical trials involving 874 patients with fibromyalgia. In both studies, Cymbalta reduced pain at study endpoint compared with placebo as measured by the Brief Pain Inventory (BPI) 24-hour average pain scale.(vi),(vii) The BPI is a scale that measures the severity of pain.
Significant improvement in pain for Cymbalta vs. placebo was observed in the first week of each study. Fifty-one percent and 55 percent of patients on Cymbalta had a 30 percent improvement on the BPI at endpoint (clinically meaningful relief is considered at least 30 percent pain reduction(viii)).
In addition, 65 percent and 66 percent of patients taking Cymbalta 60 mg daily reported feeling better at endpoint as measured by the Patient Global Impression of Improvement (PGI-I). The PGI-I is a patient-rated scale that evaluates how much improvement has occurred since beginning treatment.
Cymbalta 60 mg was superior to placebo on the Fibromyalgia Impact Questionnaire (FIQ) Total Score. The FIQ is a scale that is used to assess and evaluate the impact of fibromyalgia on aspects of health and functioning believed to be most affected by the disorder.
In four pooled studies, the most commonly observed adverse events in Cymbalta-treated patients with fibromyalgia (greater than or equal to 5 percent and at least twice placebo) were nausea (29 percent), dry mouth (18 percent), constipation (15 percent), decreased appetite (11 percent), sleepiness (11 percent), increased sweating (7 percent) and agitation (6 percent). In the placebo-controlled clinical trials, the overall discontinuation rates due to adverse events for Cymbalta vs. placebo were 20 percent and 12 percent, respectively.(ix)
Serotonin and norepinephrine in the brain and spinal cord are believed to both mediate core mood symptoms and help regulate the perception of pain. Based on preclinical studies, Cymbalta is a balanced and potent reuptake inhibitor of serotonin and norepinephrine that is believed to potentiate the activity of these chemicals in the central nervous system (brain and spinal cord). While the mechanism of action of Cymbalta is not fully known, scientists believe its effects on depression and anxiety symptoms, as well as its effect on pain perception, may be due to increasing the activity of serotonin and norepinephrine in the central nervous system.
Cymbalta is approved in the United States for the acute and maintenance treatment of major depressive disorder, the acute treatment of generalized anxiety disorder, and the management of fibromyalgia and diabetic peripheral neuropathic pain in adults age 18 years and older. Cymbalta is not approved for use in pediatric patients.