Why Treatment Advances in Fibromyalgia Have Been Slow
Fibromyalgia is a common medical condition characterized by chronic widespread muscle pain, fatigue, and sleep disturbance affecting two to three percent of the total population. It is five to ten times more common in women than men, increases with age and can also be worsened by many factors, including physical trauma and emotional stress. In this post, I share a few thoughts on why advances in the field have been slow and what developments may be coming soon.
Fibromyalgia involves central amplification of peripheral sensory signals, so that otherwise normal sensations are perceived as painful. Most patients afflicted with fibromyalgia also experience excessive tenderness, fatigue, sleep disturbances, problems concentrating, and functional impairment. A major obstacle to diagnosis is the absence of specific laboratory or imaging tests for fibromyalgia, although lab testing can be used to rule out other conditions associated with fatigue. Since the symptoms of fibromyalgia are shared with other conditions, patients should also be evaluated for mood disorders and sleep impairment.
In the decades prior to the introduction of the American College of Rheumatology’s (ACR) classification criteria in 1990, there was considerable skepticism about fibromyalgia as a legitimate medical condition. The 1990 ACR criteria ushered in an era of increased recognition of fibromyalgia and provided a standardized diagnostic approach. This was a boon for academic rheumatologists and even more so for researchers looking to test the efficacy of drugs. Despite widespread dissemination of the diagnostic criteria, skepticism abounded. For example, the very year ACR published the criteria for fibromyalgia, the British Journal of Rheumatology and the Canadian Family Physician journal published papers questioning the existence of fibromyalgia. However, the ACR criteria provided a major boost to research, resulting in the 2006 FDA approval of pregabalin (Lyrica®); the 2008 approval of duloxetine (Cymbalta®); and the 2009 approval of milnacipran (Savella®), which remain the only FDA-approved medicines for the treatment of fibromyalgia.
Although the ACR classification system was a major advance, it proved problematic in a number of ways. First, it required assessment of tenderness on pressure (tender) points in at least 11 of 18 specified sites and the presence of widespread pain for a diagnosis of fibromyalgia. Second, tender point assessment failed to address the symptoms that bothered patients. And finally, digital palpation of 18 tender points was hard for most non-rheumatologists to perform. It became apparent that primary care physicians had neither the time nor the training to perform extensive tender point assessment. Therefore, in 2010, the ACR simplified its criteria, eliminating tender point assessment, and changed the definition of fibromyalgia to an illness characterized by self-reported multiple painful regions and core symptoms such as such as fatigue, sleep disturbances and impaired cognition. In 2011, the ACR provided a self-report version for survey and clinical research purposes, thus spurring further testing of treatments for fibromyalgia. In December 2016, ACR released a further revision to the 2010/2011 criteria which reduce misclassification of regional pain disorders and improve diagnostic clarity. The 2016 modifications provide physician-based criteria for patient diagnosis and self-report criteria for research studies.
Although there are no definitive treatments for fibromyalgia, evidence indicates that lifestyle changes including relaxation, patient education, counseling, and exercise all improve symptoms and should therefore be an active part of any management program. In recent years, several promising drug treatments have failed in clinical trials, although companies such as Astellas, Daiichi Sankyo, Zynerba and SWITCHBIOTECH are pursuing new treatments for fibromyalgia. As awareness is raised and research studies continue, the contributing causes of fibromyalgia will be better understood and allow for the development of superior treatments. Najib Babul, PharmD, MBA