Efficacy and Safety of Intravenous Immunoglobulin as Adjuvant Treatment for Refractory Neuropathic Pain. Results of an Open-Label, Multicenter Study

Introduction. Neuropathic pain is frequently associated with many peripheral nervous system diseases and its successful treatment is an area of significant and critical unmet need. Methods. Twenty adult outpatients of both sexes who had been suffering from painful polyneuropathy resistant to conventional therapies for at least 6 months and up to a maximum of 5 years and who reported severity of pain >60 units on a visual analog scale (VAS) at baseline were included in this open-label pilot study. Patients were randomly 1:1 allocated to receive adjuvant intravenous immunoglobulin (IVIG) (Flebogamma (R), 2 g/kg) in addition to their regular therapy or to continue with the previous therapy (control group). Results. The mean value of pain intensity (VAS) in the IVIG group dropped from 88 at baseline to 49 after the first week, and to 28 after 4 weeks, while values in the control group only slightly changed, from 85 to 78 after 1 week and to 75 after 4 weeks (P < 0.01). Almost 100% of patients reported strong/medium pain (Short Form McGill Pain Questionnaire) in both groups at baseline, while after 48 weeks, pain was reduced to moderate/light in 90% of patients in the IVIG group, whereas no improvement was reported in the control group (P < 0.01). In patients' quality of life, scores of the IVIG group (Short Form 36, Clinical Global Impression of Change, and Patient Global Impression of Change questionnaires) in all the follow-up were significantly higher than those of the control group (P < 0.01). Conclusion. This unblinded pilot study showed a beneficial effect of IVIG on neuropathic pain intensity and quality of life in patients resistant to conventional treatments