α1-Antitrypsin in fibromyalgia: results of a randomized, placebo-controlled, double-blind and crossover pilot trial

To assess clinical effect of a human plasma-derived alpha-1 antitrypsin (AAT) concentrate in reducing pain severity of patients with fibromyalgia (FM).

Thirteen subjects with FM completed a randomized, double-blind, placebo-controlled, crossover study which consisted of 9 weeks trial of AAT or placebo with a washout period of 6 weeks. Primary efficacy endpoint was change on pain severity score, assessed by a daily visual analogue scale (VAS) for pain. Other outcome measures included a tender point score, the Fibromyalgia Impact Questionnaire, (FIQ), the Medical Outcomes Study Short Form 36 (SF-36), the Health Assessment Questionnaire Disability Index (HAQ-DI), the Hospital Anxiety and Depression Scale (HADS) and tiredness score evaluated by VAS.

No statistically significant differences were observed in either pain severity or other secondary outcome measures in either of the treatment groups, or between treatment groups in either of the treatment periods. No carryover or order of intervention effect was observed from one treatment to the other. Both investigational interventions were generally well tolerated, and vital signs during the drug infusions were within the respective normal ranges.

Treatment with a human plasma-derived AAT concentrate did not demonstrate significant improvement over placebo on reducing pain severity and other symptoms of FM. Further research should examine other FM subpopulations and drug doses.