Clinical Properties of a Novel Liquid Intravenous Immunoglobulin: Studies in Patients with Immune Thrombocytopenic Purpura and Primary Immunodeficiencies

Abstract

<b>Background:</b> We have developed a novel liquid intravenous immunoglobulin (IVIG-F10). It consists of a nanofiltered 12% immunoglobulin G (IgG) solution, stabilized with nicotinamide, L-proline and L-isoleucine. The efficacy, tolerability, safety, and pharmacokinetics of this product were assessed in patients with chronic immune thrombocytopenic purpura (ITP) and primary humoral immunodeficiencies (PID). <b>Patients and Methods:</b> 33 chronic ITP patients with platelet counts of < 20 × 10⁹/l were treated with IVIG-F10 or Sandoglobulin at doses of 0.4 g/kg body weight on 5 consecutive days. The primary efficacy endpoint was an increase in platelet counts to ≧50 × 10⁹/l. Secondary endpoints were time to and duration of platelet response and regression of bleeding. 34 PID patients with X-linked agammaglobulinemia, common variable immunodeficiency or IgG subclass deficiency were treated for 6 months with IVIG-F10 or Sandoglobulin at doses of 0.3–0.8 g/kg, infused at 3- or 4-week intervals. The primary efficacy endpoint was the number of days absent from school/work. Secondary endpoints were feeling of well-being, days of hospitalization, and use of antibiotics. <b>Results:</b> In ITP patients, the primary endpoint was met by 12/16 patients on IVIG-F10 and by 12/17 patients on Sandoglobulin (p = 1.000). Results of the secondary endpoints were comparable in the two study groups. In the PID study, 10/17 patients on IVIG-F10 and 9/17 patients on Sandoglobulin missed days at school/work, with monthly mean absences of 0.7 and 0.6 days (p = 0.746), respectively. There were no significant differences in the outcome of the secondary endpoints. Pharmacokinetics showed constant peak and trough serum IgG levels in PID patients. The median half-life (t_1/2) of IgG was 33 days in the IVIG-F10 group and 41 days in the Sandoglobulin group. For anti-HBsAg, median t_1/2 values were shorter, i.e. 17 and 19 days for IVIG-F10 and Sandoglobulin, respectively. In the ITP study, adverse events related to study drug were suspected in 9 and 14 patients treated with IVIG-F10 and Sandoglobulin, respectively; in the PID study adverse events occurred in 8 and 9 patients, respectively. Viral safety was ascertained in both studies by serology supplemented with nucleic acid amplification testing. Serum levels of the stabilizers transiently increased after infusion of IVIG-F10, but were back to baseline at the following day. <b>Conclusions:</b> The clinical studies in patients with chronic ITP and PID showed that the efficacy, tolerability, safety, and pharmacokinetics of IVIG-F10 were comparable to the properties of Sandoglobulin.