Background: Chronic inflammatory demyelinating polyradiculoneuropathy trials have demonstrated the efficacy of IV immunoglobulin vs placebo. However, these trails have not addressed the long-term impact on health-related quality of life (HRQoL).
Methods: One hundred seventeen patients in a randomized, double-blind, response-conditional crossover trial received immune globulin IV, 10% caprylate/chromatography purified (IGIV-C [Gamunex(R)]), or placebo every 3 weeks for up to 24 weeks in the first period (FP). Participants whose inflammatory neuropathy cause and treatment disability score did not improve by >/=1 point received alternate treatment in a 24-week crossover period (CP). In either period, participants who improved and completed treatment were eligible to be randomly reassigned to a blinded 24-week extension phase (EP). HRQoL analyses were conducted using the Short Form-36(R) (SF-36) and the Rotterdam Handicap Scale (RHS).
Results: In the FP, greater improvements in both SF-36 physical and mental component scores were observed with IGIV-C vs placebo, with a significant improvement in the physical component score (difference 4.4 points; 95% confidence interval [CI] 0.7-8.0). Improvements in all SF-36 domains favored IGIV-C vs placebo, with physical functioning, role-physical, social functioning, and mental health reaching significance. Participants receiving IGIV-C experienced a larger improvement in RHS vs those receiving placebo (difference 3.4 points; 95% CI 1.4-5.5; p = 0.001). In the CP, similar general trends were observed. In the EP, mean SF-36 improvements were generally improved or maintained in participants who continued IGIV-C therapy; however, worsening was observed in participants re-randomized to placebo.
Conclusions: Long-term therapy with immune globulin IV, 10% caprylate/chromatography purified, improves and maintains health-related quality of life in chronic inflammatory demyelinating polyradiculoneuropathy.