Cost-minimization analysis of IgPro20, a subcutaneous immunoglobulin, in Japanese patients with primary immunodeficiency.

PURPOSE: IgPro20, Hizentra(®) an L-proline-stabilized 20% human subcutaneous immunoglobulin (SCIG), has been shown in a Phase III pivotal study to be well tolerated and efficacious in adult and pediatric Japanese patients with primary immunodeficiency. Economic aspects of SCIG treatment in comparison with previous intravenous immunoglobulin (IVIG) therapy were analyzed in this Phase III study in Japan.

METHODS: Twenty-four Japanese patients with primary immunodeficiency on IVIG treatment were switched to IgPro20 at an equivalent dose (full analysis set). The study consisted of a screening period, an IVIG treatment period with 3 planned infusions every 3 or 4 weeks, a 12-week SCIG wash-in and wash-out period, and a 12-week SCIG efficacy period. The difference in medical cost and productivity loss resulting from changes in hospital frequency between the SCIG and IVIG treatment was evaluated. Information about treatment cost was collected as part of the Life Quality Index questionnaire. In addition, productivity loss and hospital-related absenteeism were evaluated.

FINDINGS: Life Quality Index scores for all domains were higher with SCIG than with IVIG in this patient population. In the full analysis set, the mean (SD) Life Quality Index score of the Costs domain increased from 45.1 (26.34) at Week 1 (IVIG period) to 71.9 (18.52) at Week 24 (end of the SCIG efficacy period), representing a mean change of 26.74 and a large score improvement effect size (1.01). Median productivity loss was reduced by 60% from baseline to Weeks 12 and 24. This resulted in a reduction in costs of JPY 10,875 per patient per month at Weeks 12 and 24. Subcutaneous treatment with IgPro20 also reduced hospital-related absenteeism. The number of patients, parents, or guardians who were not absent from work or housework duties and had no reduction in working time increased from 4 (17.4%) at Week 1 to 9 (39.1%) at Week 24. Similar results were obtained in the per-protocol set (n = 21).

IMPLICATIONS: Switching from IVIG to SCIG reduced markedly productivity loss and hospital-related absenteeism. The reduction in hospital visit frequency due to the use of home-based IgG therapy enabled by the change in administration route is expected to produce an important pharmacoeconomic benefit in Japan. Study Code: ZLB06_002CR, ClinicalTrials.gov identifier: NCT01199705.