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LAS VEGAS -- Biosimilar switching was not tied to flare in patients with inflammatory bowel disease (IBD), according to a retrospective cohort study.

Patients who switched from infliximab (Remicade) to an infliximab biosimilar, and then switched again to a different biosimilar or back to infliximab, were no more or less likely to experience a disease flare within 12 months than those who remained on infliximab or switched once, reported Jason K. Hou, MD, of Baylor College of Medicine in Houston, and colleagues in a poster at the Crohn's & Colitis Congress.

The odds of a steroid escalation, hospitalization, or emergency department (ED) visit within 12 months were similar for patients who remained on infliximab (OR 1.12, 95% CI 0.68-1.84) or switched once (OR 0.64, 95% CI 0.36-1.12), compared to those who switched twice, after accounting for demographic and patient differences.

"Just in the past few years, we've had multiple biosimilars for infliximab, and we're getting more and more of them," with insurance companies sometimes requiring patients to switch from infliximab to one of those biosimilar medications, said Elisa Boden, MD, of Oregon Health & Science University in Portland.

"We have data that shows that one switch from infliximab to an infliximab biosimilar is safe, meaning those patients don't have an increased risk of flaring of their disease, and they're not at a higher risk to develop antibodies to the drug, but we haven't had data showing that you can switch multiple times," she said. "So, this is a nice study that basically shows that you can switch more than one time to different medications, and there's no increased risk of flare."

Boden, who was not involved in the study, noted that the results did show that patients who switched once had significantly lower odds of infection compared to those who switched twice, but that could have been a statistical glitch or due to other factors, given the small size of the cohort.

"From my perspective, this study gives me data to be able to tell patients that they don't need to worry if their insurance is requiring them to switch," she said.

The researchers identified 487 patients with Crohn's disease and 302 patients with ulcerative colitis in a national Veterans Affairs healthcare system database between 2017-2019. Among the total 789 patients, 410 patients (51.8%) remained on infliximab without switching, 249 patients (31.6%) switched once, and 130 patients (16.5%) switched twice, either to a different biosimilar or back to infliximab. The composition of patients across all three groups did not significantly differ in terms of age (mean 54.3), gender (91.1% male), race/ethnicity (78.6% white; 13.9% African American), number of comorbidities, IBD type, years since IBD diagnosis, or other IBD medications besides infliximab.

The investigators defined a flare as an escalation of steroids, and IBD-related ED visit or hospitalization over a year of follow-up. They additionally looked at immunogenicity, risk of serious infections, and infusion reactions. Over 12 months, one in five patients (19.9%) experienced a flare, including 22.2% of those who did not switch, 15.3% of those who switched once, and 21.5% of those who switched twice (P=0.08). Among the 11.2% who had an infection, 11.5% were non-switchers, 8% were single switchers, and 16.2% were double-switchers (P=0.056).

The researchers did not identify any significant differences across the three groups in rates of flares, immunogenicity, or infusion reactions before or after adjusting for age at starting a biologic, gender, race/ethnicity, marital status, rurality of residence, number of comorbidities, IBD type, other IBD medications, and provider type. In the multivariate analysis after adjustment, single switchers appeared to have about half the risk of infection compared to those who switched twice (aOR 0.41, 95% CI 0.21-0.82).

"These findings provide reassurance that multiple infliximab biosimilar switching for IBD is not associated with flare, but further study on infection may be warranted," the investigators concluded.

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