Ideal Vial Size for Infliximab in the Treatment of Inflammatory Bowel Disease: An Analysis of Pharmaceutical Waste and Physician Opinions

BACKGROUND: Infliximab is a weight-based prescription for multiple autoimmune diseases and is dispensed only in single-use, 100mg vials. We aim to compute the quantity of infliximab waste at our site and in an ideal world where weight-based prescribing practices are followed. We estimate hypothetical waste reduction and cost-savings if a smaller vial is dispensed. We also surveyed gastroenterologists to study prescription rounding practices for infliximab. METHODS: A pre-existing registry of 426 inflammatory bowel disease patients identified 112 individuals who had received a total of 1003 infliximab administrations from December 2013 to May 2019. We calculated infliximab wastage per administration for the real world and an ideal (weight-based) world. Analysis of potential waste reduction and cost-savings was computed with the hypothetical creation of 50 and 25mg vials. Infliximab-prescribing gastroenterologists completed an online survey, determining reasons for rounding of weight-based prescription, rounding practices, and biosimilar use. RESULTS: At our site, the total value of infliximab wasted was between $112738.08 and $243209.50. Utilizing 50 and 25mg vials would reduce this waste by 92.2% and 99.4%, respectively. If prescriber guidelines were followed precisely, the total value of waste was between $132781.08 and $286448.19. Utilizing 50 and 25mg vials would reduce waste by 50.39% and 75.34%, respectively. The physician survey revealed that 68.1% rounded doses while only 31.9% prescribed exact weight-based doses. CONCLUSIONS: Infliximab-prescribing gastroenterologists considered reducing drug waste as a common reason in their rounding practices. Our analysis demonstrates significant waste reduction and cost-savings are possible with the introduction of 50 and 25mg vials.