患者負担から見たバイオシミラー使用における得失とその問題点の克服に向けた調査研究

抄録

Increases in national healthcare costs are heightening concerns for Japanese society. In recent years, the development and utilization of biosimilars (BSs) has become an area of focus because they are 23-30% cheaper. However, the use of Infliximab BS does not necessarily ensure the reduction of patient payments in Rheumatoid Arthritis (RA) cases. This paradox adversely affects the wider use of Infliximab BS. Its market penetration in Japan is less than 1%. This may indicate a significant loss for the both national healthcare scheme and patients. It is critical to identify the causes and possible remedies. We conducted a study with simulated one-year RA patient models and calculated total monthly payments for Infliximab BS and branded biologics (BBs).
Problems arise when three conditions are met: patient’s age under 70, annual income of 3.7 million yen or less, and three-dose vials daily. The main contributor to this situation is the High-Cost Medical Expense Benefit, which covers monthly payments exceeding a specified amount. This system applies to Infliximab BB users. The estimated number of patients who meet all three conditions is around 1,305 about 8% of RA patients treated with Infliximab. This shows that the majority of patients (92%) benefit from using Infliximab BS. Therefore, we do not feel that total abandonment of Infliximab BS use is justified. Our findings support that the High-Cost Medical Expense Benefit has to be adequately modified, so that BS users do not pay more for treatment than BB users.