INFLIXIMAB AND ITS BIOSIMILARS FOR INFLAMMATORY BOWEL DISEASE: ANALYSIS OF MEDICARE PART D CLAIMS AND COSTS
Authors: Goldman Modan , Jain Vedant , Mostofa Nafisa , Ramkumar Davendra 
Published: January 2024

Abstract

INTRODUCTION
Inflammatory Bowel Disease (IBD) presents a multifaceted healthcare challenge, and biologics have emerged as crucial in its management. The introduction of biosimilars, designed to enhance cost-efficiency and access, has garnered significant attention. This analysis of the Medicare Part D database assesses trends in total drug claims and costs for infliximab and its biosimilars, specifically, infliximab-dyyb (FDA approved in 2016) and infliximab-abda (FDA approved in 2017). This study aims to comprehensively evaluate the influence of biosimilars on the utilization and cost trends of infliximab in the context of IBD.

METHODS
We used Python to extract all instances of infliximab, infliximab-dyyb, and infliximab-abda prescriptions, occurring at least once between 2013-2021 in each state from the Medicare Part D prescribers database. Univariate regressions were performed independently for each state to identify the slope and significance of the change in total drug claims and costs over time. The Pearson correlation coefficient (R) was calculated for each state, and we examined national trends to determine if a consistent pattern emerged. Two study periods, 2013-2017 and 2017-2021, were used to represent infliximab trends before and after the introduction of biosimilars, respectively. North Dakota and South Dakota were excluded from the study due to data limitations, while the Virgin Islands were included.

RESULTS
Our analysis revealed varied shifts in the utilization of infliximab across states following the introduction of biosimilars (Figure 1). At the national level, biosimilars exhibited increased utilization. In contrast, both the utilization and cost of infliximab continued to rise; however, the rate of increase decelerated (Table 1). This deceleration suggests that the introduction of biosimilars has influenced prescribing patterns.

DISCUSSION
Our findings underscore transformations in the landscape of biologic utilization for IBD, subsequent to the introduction of biosimilars. The ascension of biosimilars, marked by their increased utilization, signals their acceptance due to cost-effectiveness. Meanwhile, the utilization of infliximab appears to plateau, potentially reflecting the influence of biosimilars on prescribing patterns. Given the high cost of biologics, sustained efforts are imperative to address the overall cost of therapy and management for IBD patients. While promising trends are evident with increased biosimilar utilization and cost savings, ongoing initiatives are essential to optimize the cost-effectiveness of biologic treatments, ensuring accessible care for IBD patients without compromising outcomes.

Figure 1 State trends in total infliximab claims from 2017-2021 in the Medicare Part D database. Negative Pearson correlation coefficients indicate an overall decrease in infliximab claims from 2017-2021, while positive values indicate an overall increase in claims.

Table 1 US national trends in total Medicare Part D claims and costs for infliximab and its biosimilars from 2013-2021.