Switching Australian patients with moderate to severe inflammatory bowel disease from originator to biosimilar infliximab: a multicentre, parallel cohort study

OBJECTIVE: To examine whether non-medical switching of patients with inflammatory bowel disease (IBD) from originator infliximab to a biosimilar (CT-P13, Inflectra) is safe and clinically non-inferior to continued treatment with originator infliximab.

DESIGN: Prospective, open label, multicentre, parallel cohort, non-inferiority study in seven Australian hospitals over 48 weeks, May 2017 - October 2019.

PARTICIPANTS: Adults (18 years or older) with IBD receiving maintenance originator infliximab (Remicade) who had been in steroid-free clinical remission for at least 12 weeks.

INTERVENTION: Managed program for switching patients in four hospitals from originator to biosimilar infliximab (CT-P13); patients in three other hospitals continued to receive originator infliximab (control).

MAIN OUTCOME MEASURES: Clinical disease worsening requiring infliximab dose escalation or change in therapy.

RESULTS: The switch group included 204 patients, the control group 141 patients with IBD. Ten patients in the control group (7%) and 16 patients switched to CT-P13 (8%) experienced clinical deterioration; the adjusted risk difference (control v switch group) was -1.1 percentage points (95% CI, -6.1 to 8.2 percentage points), within our pre-specified non-inferiority margin of 15 percentage points. Serious adverse events leading to infliximab discontinuation were infrequent in both the switch (six, 3%) and control (six, 4%) groups.

CONCLUSION: Switching patients with IBD from originator to biosimilar infliximab is safe and non-inferior to continuing treatment with originator infliximab. Moreover, the introduction of biosimilar infliximab, by increasing market competition, has resulted in substantial cost savings for the Pharmaceutical Benefits Scheme.