Infliximab, a chimeric monoclonal antibody directed against tumor necrosis factor, is an established treatment for Crohn's disease but not ulcerative colitis.
Only 2 randomized, double-blind, placebo-controlled studies were conducted in adults with ulcerative colitis assessing the efficacy of infliximab.
These 2 trials included the Active Ulcerative Colitis Trials 1 and 2, or ACT 1 and ACT 2, respectively.
Dr Paul Rutgeerts and colleagues evaluated the outcomes of these trials and the efficacy of infliximab for induction and maintenance therapy.
In each study, 364 patients with moderate-to-severe active ulcerative colitis, despite treatment with concurrent medications, received placebo or infliximab.
The researchers gave the patients 5 mg or 10 mg per kilogram of body weight infliximab intravenously at weeks 0, 2, and 6.
This was followed by infliximab given every 8 weeks through week 46 in ACT 1 or week 22 in ACT 2.
|69% of patients who received 5 mg of infliximab had a clinical response at week 8|
|New England Journal of Medicine|
Patients were followed for 54 weeks in ACT 1 and 30 weeks in ACT 2.
In ACT 1, 69% of patients who received 5 mg of infliximab and 61% of those who received 10 mg had a clinical response at week 8.
The team noted that 37% of those who received placebo had a clinical response at week 8.
A response was defined as a decrease in the Mayo score of at least 3 points and at least 30%.
This definition was accompanied with a decrease in the subscore for rectal bleeding of at least 1 point or an absolute rectal-bleeding subscore of 0 or 1.
In ACT 2, the team found that 64% who received 5 mg of infliximab and 69% of those who received 10 mg had a clinical response at week 8.
This was compared with 29% of those who received placebo in the same trial.
In both studies, the researchers found that patients who received infliximab were more likely to have a clinical response at week 30.
In ACT 1, more patients who received 5 mg or 10 mg of infliximab had a clinical response at week 54 than did those who received placebo.
Dr Rutgeerts team concludes, “Patients with moderate-to-severe active ulcerative colitis treated with infliximab at weeks 0, 2, and 6 and every 8 weeks thereafter were more likely to have a clinical response at weeks 8, 30, and 54 than were those receiving placebo.”