Infliximab Pricing in International Economic Evaluations in Inflammatory Bowel Disease to Inform Biologic and Biosimilar Access Policies: A Systematic Review

Background. Policies mandating the use of lower cost biosimilars in patients with inflammatory bowel disease (IBD) have created concerns for patients who prefer their original biologic. Purpose. To inform the cost-effectiveness of biosimilar infliximab treatment in IBD by systematically reviewing the effect of infliximab price variation on cost-effectiveness for jurisdictional decision making. Data Sources. MEDLINE, Embase, Healthstar, Allied and Complementary Medicine, Joanna Briggs Institute EBP Database, International Pharmaceutical Abstracts, Health and Psychosocial Instruments, Mental Measurements Yearbook citation databases, PEDE, CEA registry, HTA agencies. Study Selection. Economic evaluations of infliximab for adult or pediatric Crohn's disease and/or ulcerative colitis published from 1998 through 2019 in which drug price was varied in sensitivity analysis were included. Data Extraction. Study characteristics, main findings, and results of drug price sensitivity analyses were extracted. Studies were critically appraised. The cost-effective price of infliximab was determined based on the stated willingness-to-pay (WTP) thresholds for each jurisdiction. Data Synthesis. Infliximab price was examined in sensitivity analysis in 31 studies. Infliximab showed favorable cost-effectiveness at a price ranging from CAD $66 to $1,260 per vial, depending on jurisdiction. A total of 18 studies (58%) demonstrated cost-effectiveness ratios above the jurisdictional WTP threshold. Limitations. Drug prices were not always reported separately, WTP thresholds varied, and funding sources were not consistently reported. Conclusion. Despite the high cost of infliximab, few economic evaluations examined price variation, limiting the ability to infer the effects of biosimilar introduction. Alternative pricing strategies and access to treatment could be considered to enable IBD patients to maintain access to their current medications.