Escalating the dose of subcutaneous (SC) CT-P13, a biosimilar of infliximab, from 120 to 240 mg every 2 weeks appears to bring back the efficacy of the drug in patients with inflammatory bowel disease (IBD) who no longer respond to treatment, suggests a study presented at 2025 Crohn's & Colitis Congress.

In addition, the “[s]afety profiles including immunogenicity results were generally comparable between patients with or without dose escalation,” said lead investigator Dr Silvio Danese, professor of Gastroenterology at Vita Salute San Raffaele University and IRCCS San Raffaele Hospital in Milan, Italy. “No new safety concerns were found after dose escalation.”

Danese and his team performed a post hoc analysis to examine the efficacy, safety, and immunogenicity of treatment with CT-P13 SC dose escalation in patients who initially responded but then lost response according to the loss of response (LOR) criteria in LIBERTY-UC (ulcerative colitis) and LIBERTY-CD (Crohn’s disease) studies. Both studies were carried out in parallel for more than 54 weeks.

Patients with moderate-to-severe active UC and CD received three doses of infliximab 5 mg/kg intravenously as induction therapy. At week 10, clinical responders were randomly assigned (2:1) to receive either CT-P13 SC 120 mg or placebo every 2 weeks as maintenance therapy. From week 22, those who received CT-P13 SC 120 mg every 2 weeks and who met LOR criteria were allowed to escalate their dose to 240 mg (two shots of CT-P13 SC 120 mg) every 2 weeks.

Of the participants, 294 in the UC study and 231 in the CD study were randomized to CT-P13 SC 120 mg. Dose escalation from 120 to 240 mg prior to week 54 occurred more frequently in the UC than the CD study (27.6 percent vs 16.9 percent). Among the dose-escalated patients, 74.1 percent and 51.3 percent received an initial dose of CT-P13 SC 240 mg at week 22 in the UC and CD studies, respectively. [Inflamm Bowel Dis 2024;30(Suppl 1):S00]

IBD patients in both studies achieved clinical remission (UC: 24.7 percent; CD: 53.8 percent) or endoscopic response (CD: 28.2 percent) following the dose escalation.

Danese pointed out that dose-escalated patients had almost “a half, statistically significant, reduction in modified Mayo score in UC and CDAI score in CD at week 54” when compared to the first dose escalation visits.

Safety profile

In the maintenance period of both studies, the incidence of treatment-emergent adverse events (TEAEs) did not significantly differ between patients with dose escalation and those without: UC (72.8 percent vs 65.2 percent) and CD (71.1 percent vs 72.5 percent). Among the TEAEs, infection rates between the two cohorts were 27.2 percent vs 28.4 percent in UC and 35.6 percent vs 30.1 percent in CD.

Likewise, the rates of antidrug antibody (ADA) positive conversion up to week 54 were compared between patients with and without dose escalation: UC (55.7 percent vs 67.3 percent) and CD (68.2 percent vs 64.4 percent).

“Dose escalation of CT-P13 SC from 120 mg to 240 mg every 2 weeks may be effective in restoring efficacy,” Danese said.