In these analyses, the safety of infliximab appeared comparable to that of conventional immunomodulators, the researchers note in a report online May 22 in the American Journal of Gastroenterology.
Since being approved more than a decade ago for the treatment of moderately-to-severely active IBD, the TNF antagonist infliximab has gained “wide acceptance as a highly effective treatment option for IBD. As a result, longer-term safety data are becoming available,” Dr. Gary R. Lichtenstein from the Hospital of the University of Pennsylvania in Philadelphia, and colleagues note in their paper.
They pooled safety data from 10 clinical trials (2385 patients) of infliximab in IBD, including the five pivotal phase 3 trials (ACCENT I and II, SONIC, and ACT 1 and 2). In four of the five pivotal randomized controlled trials, treatment with immunomodulators (i.e., azathioprine, 6-mercaptopurine, and methotrexate) or with corticosteroids was permitted. The five RCTs contibuted data from 1713 patients who received infliximab 5 or 10 mg/kg and 406 who received placebo.
The pooled analysis, say the researchers, revealed “no increase in infections, serious infections or malignancy with infliximab vs placebo.” Still, “all patients should be screened for pre-existing infections before the start of any immunosuppressive therapy,” the authors remind clinicians.
The researchers say mortality and infection-related mortality appeared unaffected by infliximab or immunomodulator treatment. They also note that their findings are “generally consistent” with conclusions drawn by other researchers.
Overall, 13 patients (2 placebo-treated, 11 infliximab-treated) had a malignancy (excluding nonmelanoma skin cancer) during the 10 IBD trials, which equates to incidences of 0.60 and 0.53 per 100 patient-years, among placebo- and infliximab-treated patients, respectively.
The analysis also showed that, compared to patients with no immunomodulator user, immunomodulator-treated patients with UC demonstrated a higher incidence of infection (120.07 vs 92.47 per 100 patient-years) and immunomodulator-plus-placebo-treated CD patients demonstrated a higher incidence of malignancy (1.84 vs 0.00 per 100 patient-years).
The finding of a higher incidence of malignancy in placebo-treated patients receiving vs those not receiving immunomodulators “may support others suggesting that the thiopurines AZA and 6-MP are associated with a moderately increased risk of malignancy,” the authors say.
Despite their findings, the authors say, “It is still not certain whether or not infliximab use increases the risk of malignancy, but it is possible that the impact of infliximab is no worse than that of conventional immunomodulators and that, by effectively controlling inflammation, infliximab may contribute to a lower malignancy risk in IBD. The latter possibility requires further confirmation with longer-term data.”