All gains in infliximab biosimilar use have gone to Inflectra
CHICAGO — Researchers have observed a “modest uptake” in the use of biosimilars for infliximab in the past 18 months, although all such gains are among prescriptions for Inflectra, one of two biosimilars for the drug available in the United States, according to data presented at the ACR/ARHP 2018 Annual Meeting.
“The first biosimilar TNF inhibitor was approved by the FDA in 2016,” Katherine P. Liao, MD, MPH, from the division of rheumatology, immunology and allergy at Brigham and Women’s Hospital told attendees. “Currently, the biosimilars available on the market are for the biologic infliximab. The biosimilars for infliximab approved by the FDA are Inflectra, Renflexis and Ixifi. However, at this point, we have very limited data on TNF inhibitor biosimilar utilization in the United States.”
Although the FDA has approved three biosimilars for infliximab (Remicade, Janssen), only Inflectra (infliximab-dyyb, Celltrion) and Renflexis (infliximab-abda, Samsung Bioepis) are currently on the market in the United States. To analyze the early prescribing patterns for these drugs, Liao and colleagues reviewed data from the American College of Rheumatology’s Rheumatology Informatics System for Effectiveness (RISE) Registry, which contains electronic medical record information from 245 rheumatology practices across the United States.
Focusing on data from Sept. 1, 2016 — 1 month prior to the first biosimilar prescription — through March 31, 2018, the researchers identified biosimilar data through a combination of billing codes and text string searches for Inflectra and Renflexis. In addition, they extracted information on demographics, diagnosis codes, location of practice and insurance. The researchers used descriptive statistics to compare patients who were ever treated with a biosimilar compared with the originator drug.
According to Liao, 857 patients at baseline received a biosimilar at 73 rheumatology practices, representing 30% of all practices in the RISE registry. All of these prescriptions were for Inflectra, Liao said. Among patients prescribed Inflectra, 68.5% had a diagnosis code for rheumatoid arthritis, compared with 48.1% of those receiving the originator drug. The highest numbers of prescriptions for Inflectra were from California, with 137; West Virginia, with 101; and Texas, with 96. Among patients who were prescribed Inflectra, 63.4% had previously received Remicade. Increases in Inflectra use were modest, without any significant change in overall TNF inhibitor use among patients at practices who treated one or more patient with an infliximab biosimilar.
“Among infliximab biosimilars, only [Inflectra] has been prescribed,” Liao said. “Patients initiated on an infliximab biosimilar, compared to original infliximab, were more predominantly white, the most common diagnosis was RA and a higher percentage were on Medicare compared to commercial insurance. In addition, among RISE practices, we did see a proportion of infliximab biosimilar use over the originator, particularly in Nevada and George. The uptake of infliximab biosimilar use has been gradual, currently standing at about 2.3% of all TNF inhibitors in RISE.” – by Jason Laday
Liao KP. Abstract 1891. Presented at ACR/ARHP Annual Meeting, Oct. 20-24, 2018; Chicago.
Disclosure: Liao reports no relevant financial disclosures.