S0765 Infliximab Biosimilar Use for Inflammatory Bowel Disease: A National Veterans Affairs Experience

Abstract

INTRODUCTION: This study described real world use of infliximab (IFX) products for Inflammatory Bowel Disease (IBD), within the context of Veterans Affairs National Formulary (VANF) Policy. IFX products included the IFX originator (IFX-orig) and biosimilars (IFX-dyyb, IFX-abda). FX-orig was replaced by IFX-dyyb as the preferred IFX product on the VANF in May 2017, and IFX-dyyb was replaced by IFX-abda in September 2018. Per policy, Veterans with prior IFX experience may continue using the non-formulary product, but IFX naïve initiators are directed to select the VANF product. The purpose of this study was to describe IFX product selection for Crohn’s Disease (CD) and Ulcerative Colitis (UC) during the time frame when biosimilars entered the VA and obtained VANF status. The secondary purpose was to describe IFX product use during the 1st six months of study follow-up. METHODS: Data sources included national electronic health record and administrative datasets generated from routine clinical care in the US. From 1/1/2016 to 12/31/2019, Veterans were included in the study upon receipt of their first IFX product. Eligible participants had a diagnosis code for UC or CD and had entered the VA >365 days prior to their index treatment. Monthly and annual IFX product selection was described for IFX-naïve and IFX-experienced patients. Frequency, proportions and 95% CIs were used to describe IBD cohort characteristics and initial IFX product selection during the study period. RESULTS: IFX products were used in 3204 Veterans with IBD (60.2% CD, 39.8 UC). The mean age was 52.5 and 90% were male (Table 1). Non-formulary use of IFX-orig occurred in higher percentage of IFX experienced patients than IFX-naïve patients (Table 2). Product selection reflected VANF, with the highest frequencies of IFX-orig in 2016–2017, IFX-dyyb during 2018, and IFX-abda during 2019. The time delay between the initial designation as the preferred IFX product and becoming the most frequently used IFX product in IFX-naïve Veterans was 5 months for IFX-dyyb and 2 months for IFX-abda (Figure 1). CONCLUSION: Adoption of the initial biosimilar added to VANF in May 2017 was slower than adoption of the Sept. 2018 formulary change. Additional work is needed to understand utilization patterns with IFX biosimilars vs non-formulary IFX products and reasons for delay in formulary compliance. Assessment of ongoing product use will provide important details on how VANF influences IFX use in patients with and without prior IFX experience.Table 1Table 2Figure 1: Patterns of IFX-orig and Biosimilar Use Over Time