P022   Utilization patterns of infliximab originator to infliximab biosimilar in US Veterans

P022   Utilization patterns of infliximab originator to infliximab biosimilar in US Veterans

Pinnell Derek1, Johnson Jessica1, Sauer Brian1, Pei Shoabo1, Chen Wei1, Rojas Jorge1, Gawron Andrew2, Baker Joshua3, Curtis Jeffrey4, Star Vicki5, Wu David5, Walsh Jessica1
1 University of Utah/VA Salt Lake City Healthcare System, Salt Lake City, United States, 2 University of Utah School of Medicine, Salt Lake City1, United States, 3 Perelman School of Medicine, University of Pennsylvania, Philadelphia, United States, 4 University of Alabama, Tuscaloosa, United States, 5 Merck & Co., Inc., Kenilworth, United States

BACKGROUND: The study objective was to describe utilization of infliximab (IFX) products, including the infliximab originator Remicade (IFX-orig) and biosimilars Inflectra (IFX-dyyb), and Renflexis (IFX-abda), during a 6-month follow-up period.
 

METHODS: Data were collected from national Veterans Affairs (VA) administrative and electronic medical record datasets between 9/1/2016 to 12/31/2019. The index date was the first infliximab biosimilar dispensation date during the study period. Veterans were required to be enrolled in the VA for >365 days prior to their index date.  Veterans were sub-grouped according to their history of infliximab exposure prior to the index date (IFX-naïve or IFX-experienced), and disease indication (Crohn’s Disease (CD), Ulcerative Colitis (UC), Rheumatoid Arthritis (RA), Ankylosing Spondylitis (AS), Psoriatic Arthritis (PsA), Psoriasis (PsO), and Others). The distribution of patients on each IFX product was assessed over time. Persistence on the index product and proportion of patients switching to a different IFX product were determined. Other measures of IFX utilization included the average weight-based dose, cumulative dose, the number of dispensed doses, and proportion of days covered (PDC).   
 

RESULTS: Among 5,227 Veterans, the mean age was 54.5 (95% CI: 54.1-55.0) years and 88.4 (87.6-89.3)% were male. 70.2 (69.0-71.4)% were initiated on IFX-orig, 13.4 (12.5-14.4)% IFX-dyyb, and 16.4 (15.4-17.4)% IFX-abda.  51.2 (49.9-52.6)% were IFX-naïve. Disease indications included CD (40.1 (38.7-41.4)%), UC (26.7 (25.5-27.9)%), RA (12.0 (11.1-12.9)%), AS (5.9 (5.3-6.6)%), PsA (5.4 (4.8-6.0)%), PsO (2.3 (1.9-2.7)%), and Others/Unknown (7.6 (6.9-8.4)%). The percentage of IFX users on a biosimilar increased between the beginning and end of the study (from 0.1% to 86%). The percentage of Veterans persistent on their index IFX product throughout the 6-month follow-up period was 78.2%. Within the subset of Veterans who were not persistent on their index IFX product, 26.4% switched to a different IFX product.  The mean number of times IFX was dispensed during the 6-month follow-up was 4.25 (4.20-4.30) (IFX-orig 4.24 (4.19-4.30), IFX-dyyb 4.07 (3.93-4.22), IFX-abda 4.41 (4.28-4.53)).  The average weight-based dose was 5.95 (5.89-6.01) mg/kg (IFX-orig 6.09 (6.02-6.17) mg/kg, IFX-dyyb 5.70 (5.56-5.83) mg/kg, IFX-abda 5.56 (5.44-5.67) mg/kg) and the mean cumulative dose was 2331.9 (2291.8-2371.9) mg (IFX-orig 2390.7(2341.7-2439.7) mg, IFX-dyyb 2120.1 (2015.9-2224.3) mg, IFX-abda 2253.3 (2162.9 – 2343.6) mg). The mean PDC was 0.86 (0.85-0.86) (IFX-orig 0.88 (0.87-0.88), IFX-dyyb 0.78 (0.76-0.80), IFX-abda 0.83 (0.81-0.85)). Additional IFX utilization data will be subsequently presented for the subpopulations with Crohn’s and UC.
 
 
CONCLUSION(S): The percentage of IFX users on a biosimilar increased throughout the study period. Dosing outcomes and PDC were similar with IFX-orig, IFX-dyyb and IFX-abda, suggesting biosimilars were used in a similar manner as the originator product.