Evaluation of the Validity of Vial Sizes for the Efficient Use of Tocilizumab Formulations

Abstract

Objective: Tocilizumab and infliximab are biologic drugs that are widely used for the treatment of rheumatoid arthritis (RA). The dosage of these injectable RA drugs is calculated based on body weight. However, injectable RA drugs are used only once due to stability and sterility concerns. For expensive biologic drugs, drug disposal wastage needs to be reduced. Tocilizumab is approved in three vial sizes: 80, 200, and 400 mg. In this study, we evaluated the validity of these tocilizumab vial sizes to help resolve the issue of excess residual drug.

Methods: A log-normal distribution was assumed for body weight, and 10,000 hypothetical cases were created using the programming language R. We analyzed the average wasted dose rate per vial (%) by gender after considering different vial size combinations.

Results: The average wasted dose rate per vial of tocilizumab was estimated to be 3.7% for males and 4.7% for females.

Conclusion: The three vial sizes of 80, 200, and 400 mg are reasonable for tocilizumab. The average wasted dose rate per vial of infliximab was estimated to be 17.7% for males and 22.6% for females. The average wasted dose rate per vial was lower for tocilizumab than infliximab. Tocilizumab is administered in a dose range of 200 to 1,100 mg with three different vial sizes in multiples of 40 mg. However, infliximab is administered in a dose range of 50 to 400 mg with a single vial size of 100 mg. Multiple vial sizes should be prepared to ensure the efficient use of limited medical resources. It is also expected that the method employed for this hypothetical case model will be applied to other drugs for which disposal wastage is a problem and used to set appropriate vial size combinations.