D-Ribose for Fatigue in Subjects With Fibromyalgia

Major Inclusion Criteria: * must have a diagnosis of primary fibromyalgia, as defined by the 1990 American College of Rheumatology (ACR) Criteria for the Classification of Fibromyalgia made at least 6 weeks prior to the Pretreatment Screening Visit; * must have a score of ≥5 on the Subject's Assessment of Fatigue 11-point numerical rating scale (NRS) at the Pretreatment Screening and Baseline Visits; * if taking acetaminophen or other non-opioid analgesics, NSAIDs, fibromyalgia medications, medications to induce sleep, or prednisone ≤ 10 mg (or equivalent dose of other glucocorticoids), must be on stable dose(s) for at least 4 weeks prior to the baseline visit; * must have discontinued any ribose-containing products (including foods, drinks, and supplements) at least 4 weeks prior to the Pretreatment Baseline Visit. Major Exclusion Criteria: * current major depressive episode (MDE); * has been diagnosed with any autoimmune disease; * has been diagnosed with type I or type II diabetes; * has a history of cancer, other than basal cell carcinoma, stage 1 squamous cell carcinoma or cervical carcinoma in situ, that has not been in remission for at least five years prior to the Pretreatment Screening Visit; * has been diagnosed with chronic fatigue syndrome.