Summary

The general safety and efficacy of intravenous immunoglobulin(IGIV) as treatment for idiopathic thrombocytopenic purpura(ITP) has been well-studied. The current study compares thesafety and efficacy of a novel IGIV (IGIV-C; Gamunex>sup>®, 10%)with a licensed solvent/detergent-treated product (IGIV-S/D;Gamimune^®N, 10%) in treatment of ITP. Ninety-seven pediatricand adult patients with acute and chronic ITP were treated in amulti-center, prospective, randomized, double-blind parallelgroup, non-inferiority trial at 26 international sites. Baselinedata (age, duration of ITP, platelet counts, previous treatment)were comparable between groups. Patients were treated with1 g/kg/day of IGIV-C or IGIV-S/D for 2 days. The primary endpoint,proportion of patients whose platelet counts increasedfrom =20 x 10⁹/L to =50 x 10⁹/L within 7 days after dosing, was achieved by 35/39 (90%) and 35/42 (83%) of patients treatedwith IGIV-C and IGIV-S/D, respectively. A secondary endpoint,maintaining platelet counts ≥50 x 10⁹/L for ≥7 days, wasachieved by 29/39 (74%) of IGIV-C and 25/42 (60%) IGIV-S/Dtreated patients. Compared with IGIV-S/D, fewer patients treatedwith IGIV-C received corticosteroids beyond day 7 (p =0.02). Efficacy was independent of the presence of isoantibodiesor blood type, supporting mechanisms of effect differentfrom anti-D treatments. Adverse events were generally mildand occurred with similar frequency in each group. Viral safetymonitoring for HIV, HCV, HBV and Parvovirus B19 showed noseroconversions on study. In conclusion, IGIV-C is as safe andefficacious as IGIV-S/D in treatment of ITP.