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Switching from intravenous to subcutaneous infliximab (Remicade) was safe and effective for patients with inflammatory bowel disease (IBD) in clinical remission, an observational study in France showed.

Among 133 patients treated with an intravenous regimen, relapse rates were low 16 to 24 weeks after switching to subcutaneous infliximab 120 mg every other week across several dosing regimens, except for those who received 10 mg/kg every 4 weeks and required 240 mg every other week (P<0.001 for all):

• 5 mg/kg every 8 weeks: 10.2%
• 10 mg/kg every 8 weeks: 7.3%
• 10 mg/kg every 6 weeks: 16.7%
• 10 mg/kg every 4 weeks: 66.7%

A sensitivity analysis narrowing the scope to only include those with fecal calprotectin levels below 250 µg/g showed similar rates of relapse for the same dose regimens at 16 to 24 weeks after the switch (7.1%, 3.2%, 8.3%, and 75%, respectively), reported Anthony Buisson, MD, PhD, of the University Hospital Estaing in Clermont-Ferrand, France and colleagues.

This strategy "is feasible, safe and well-accepted leading to a low risk of relapse in patients with IBD, including those with escalated intravenous doses," the authors noted in .

Multivariable analysis showed that certain factors were significant predictors of relapse after the switch:

• An intravenous maintenance regimen of 10 mg/kg every 4 weeks: OR 12.4 (95% CI 1.6-98.4, P=0.017)
• Baseline fecal calprotectin levels >250 µg/g: OR 5.4 (95% CI 1.1-27.6, P=0.042)

From baseline to 4-8 weeks after the switch, reduced (41.7%) or stable (36.8%) infliximab serum levels were tied to a higher risk of relapse compared with increased serum levels (12.7%).

While "the need for higher subcutaneous dose for the most intensified IV regimens could be expected ... the key question was to define from what dose at baseline should the subcutaneous treatment be intensified?" Buisson and team wrote. "Our study addresses this question showing that only patients treated with 10 mg/kg every 4 weeks should be eligible [for] a systematic intensified subcutaneous dose (240 mg every other week)."

Among those who received an escalated dose to 240 mg every other week (n=15), clinical remission occurred in 93.3%.

While bowel damage caused by IBD can reduce quality of life, infliximab has shown the greatest efficacy in inducing and maintaining remission, Buisson's group noted. However, its therapeutic use is limited by the need for repetitive intravenous infusions every 4, 6, or 8 weeks.

The first globally approved monoclonal antibody biosimilar for infliximab, Remsima, can be self-administered at home in subcutaneous injected doses of 120 mg every other week to treat IBD and other indications. Remsima was effective in in IBD patients compared with intravenous infused dose regimens of 5 mg/kg every 8 weeks.

For this study, Buisson and colleagues examined data on 133 IBD patients in steroid-free remission across three centers in France from February to August 2021. Of these patients, 59 were on an intravenous infliximab maintenance regimen of 5 mg/kg every 8 weeks, 41 received 10 mg/kg every 8 weeks, 18 received 10 mg/kg every 6 weeks, and 15 received 10 mg/kg every 4 weeks.

Mean age was 39, and 54% were women. Nearly three-fourths had Crohn's disease, and 28% had ulcerative colitis. A quarter received concomitant immunosuppressive therapy. Mean infliximab maintenance duration was 5.4 years.

No relationships were seen between the risk of relapse and sex, BMI, body weight, Crohn's disease location/phenotype, ulcerative colitis extension, and perianal lesions, among other factors.

Of note, patient acceptability of treatment improved after the switch (6.9 vs 8.6 points on a 10-point scale, P<0.0001).

Only 16 patients experienced an adverse event. Two had intolerance to the switch with nonspecific myalgia/mild abdominal pain. Others reported mild and transient erythema, injection site pain, abdominal pain, bronchitis, fatigue, and IBD-related symptoms. No adverse events required surgery or hospitalization.

Buisson and team noted that follow-up occurred over only 6 months, which was a limitation to the study. In addition, subgroup sample sizes were small.

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