Abstract Background Infliximab (IFX) and vedolizumab (VDZ) are established advanced therapies for inflammatory bowel disease (IBD) and are available in both intravenous (IV) and subcutaneous (SC) formulations. SC delivery offers practical and system-level advantages, but real-world patterns of IV and SC use and the extent of switching between routes remain unclear. This study examined trends in administration route and switching for both therapies. Methods Crohn’s Colitis Care (CCCare) is a cloud-based, IBD-specific electronic medical record used in Australia and New Zealand. Only Australian data were analysed, as SC formulations were not funded in NZ during the study period. Data fed into a de-identified clinical quality registry was analysed in May 2025. People with Crohn’s disease (CD) or ulcerative colitis (UC) receiving maintenance IFX or VDZ following IV induction, and with a clinical assessment between 2021 and 2024, were included. Annual trends in administration route and switching patterns were evaluated. Results For IFX, most individuals had CD with little temporal variation. Median age decreased from 38.5 to 34.2 years and disease duration from 11.9 to 9.5 years, likely reflecting inclusion of paediatric centres into CCCare. IV maintenance declined from 95.1% to 64.7%, while SC use rose from 4.9% to 35.3% (both p 0.001). Among new maintenance courses, SC initiation increased from 10.1% to 22.0% by 2022 then plateaued (p = 0.054). Switching from IV to SC rose early (5.9% to 13.9%) before plateauing, and the time spent on IV therapy prior to switching showed no meaningful change across years (p = 0.09). For VDZ, most individuals had UC, with proportions remaining similar across years. Demographic features showed little temporal variation (median age 43.6 years; disease duration 12.4 years in 2024). IV maintenance decreased from 93.0% to 70.9%, with SC use increasing from 7.0% to 29.1% (both p 0.001). SC initiation increased from 6.2% in 2021 to 26.3% in 2024 (p = 0.003), with most of the increase occurring before 2022. Unlike IFX, switching from IV to SC did not change meaningfully over time (p = 0.25), and the duration on IV before switching remained long and stable over time (p = 0.09). Across both therapies, SC uptake increased early but subsequently plateaued, and route switching remained limited. Conclusion Although early uptake of SC IFX and VDZ was evident, its use appears to have plateaued and SC therapy remains underutilised, with most individuals continuing on IV treatment and limited switching. The modest transition to SC despite its practical advantages highlights potential clinical, perceptual, or systems-level barriers. Understanding these factors will be important for optimising treatment delivery and resource use. Conflict of interest: Dr. Wu, Rodger: No conflict of interest Su, Wai Kin: No conflict of interest Wilson, William: No conflict of interest Caquilpan, Victor: No conflict of interest Connor, Susan Jane: Grant: Research Support: Abbvie, Agency for Clinical Innovation, Amgen, BMS, Chiesi, Celltrion, DrFalk, Ferring, Janssen, Medical Research Future Fund, Pfizer, South Western Sydney Local Health District, Sydney Partnership for Health, Research and Enterprise, Takeda and The Leona M and Harry B Helmsley Charitable Trust Personal Fees: Ad Boards: Abbvie, Amgen, BMS, Celltrion, Eli Lilly, Ferring, GSK, Janssen, Organon, Pfizer, Takeda Speaker Fees: Abbvie, Cornerstones Health, Dr Falk, Ferring, Janssen, Pfizer, Sandoz, Sydney IBD School, Takeda Educational Support: DrFalk, Sandoz, Takeda Andrews, Jane Mary: Grant: The work I will present was funded via CCCure. CCCure’s funding sources include grants for research and payments for data reports from Pharma including AbbVie, J&J, Takeda, Celltrion, Falk, Ferring, BMS, Janssen, Pfizer, Sandoz
Wu et al. (Thu,) studied this question.