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®, 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 4-8 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.