Intravenous immunoglobulin (IVIg), a blood product containing pooled IgG immunoglobulins derived from human plasma.
Idiopathic thrombocytopenic purpura (ITP) caused by an abnormal immune response that leads to low platelet counts and bleeding.
Because of the growing use of IVIg in Canada (including off-label use), escalating costs, potential availability of other treatments, and uncertainty about therapeutic advantages, there is a need to assess the cost-effectiveness of IVIg in the treatment of ITP.
Methods and Results
A systematic review was conducted to identify economic evaluations that compared IVIg with alternative treatments. Four evaluations were included. Relevant clinical studies were identified. Two primary cost utility analyses were conducted.
Implications for Decision Making
- The cost-effectiveness of IVIg is more favourable in acute childhood ITP than in chronic adult ITP. In acute childhood ITP, when IVIg was compared with prednisone, anti-D, methylprednisolone, or observation, IVIg was the most costly option and resulted in the largest number of lifetime quality-adjusted life years (QALYs). IVIg has the highest probability of being cost-effective if decision makers are willing to pay more than $112,000 per QALY. These results are sensitive to the probability of intracranial hemorrhage, the IVIg dose, and the patient’s weight. In chronic adult ITP, compared with prednisone, IVIg is cost-effective if decision makers are willing to pay $2,690,000 per QALY.
- The health services impact depends on the patient population. Based on the use of foreign prevalence and incidence data to derive Canadian estimates, there are 6,090 chronic adult ITP cases compared with 268 acute childhood ITP cases. The annual per-patient maintenance costs are $26,931 for chronic adult ITP versus $1,598 for acute childhood ITP.
- Some uncertainty remains. These analyses are based on data from international sources. There is a need for Canadian patient-level health resource utilization and utility data from randomized controlled trials that compare IVIg with alternative therapies.
This summary is based on a comprehensive health technology assessment available from CADTH’s web site (www.cadth.ca): Blackhouse G, Xie F, Campbell K, Assasi N, Gaebel K, Levine M, Pi D, Giacomini M, Goeree R, Banks R. Intravenous Immunoglobulin for Treatment of Idiopathic Thrombocytopenic Purpura: Economic and Health Service Impact Analyses.