Infliximab for medical induction of remission in Crohn's disease

Background Infliximab is a monoclonal antibody that binds and neutralises tumour necrosis factor-alpha (TNF-alpha), which is present in high levels in the blood serum, mucosa and stool of people with Crohn's disease. Objectives To evaluate the benefits and harms of infliximab alone or in combination with another agent for induction of remission in Crohn's disease compared to placebo or active medical therapies. Search methods On 31 August 2021 and 4 March 2023, we searched CENTRAL, MEDLINE, Embase, ClinicalTrials.gov and World Health Organization ICTRP. Selection criteria Randomised control trials (RCTs) comparing infliximab alone or in combination with another agent to placebo or another active comparator in adults with active Crohn's disease. Data collection and analysis Pairs of review authors independently selected studies and conducted data extraction and risk of bias assessment. We expressed outcomes as risk ratios (RR) and mean differences (MD) with 95% confidence intervals (CI). We assessed the certainty of the evidence using GRADE. Our primary outcomes were clinical remission, clinical response and withdrawals due to adverse events. Our secondary outcomes were endoscopic remission, histological remission, endoscopic response, and serious and total adverse events. Main results The search identified 10 RCTs with 1101 participants. They were conducted between 1999 and 2019, and 7/10 RCTs included biologically naive participants. All but one RCT, which did not provide information, were multicentre and funded by pharmaceutical companies, and their authors declared conflicts. The age of the participants ranged from 26 to 65 years. Results were based on one study unless otherwise stated. Infliximab 5 mg/kg to 10 mg/kg may be more effective than placebo at week four for clinical remission (30/55 versus 3/25; RR 4.55, 95% CI 1.53 to 13.50; number needed to treat for an additional beneficial outcome (NNTB) 3) and response (36/55 versus 4/25; RR 4.09, 95% CI 1.63 to 10.25, NNTB 3). The evidence was low certainty. The study did not report withdrawals due to adverse events. We could not draw conclusions on the effects of infliximab 5 mg/kg to 10 mg/kg compared to placebo for fistulating participants for clinical remission (29/63 versus 4/31; RR 3.57, 95% CI 1.38 to 9.25; NNTB 4), response (48/106 versus 15/75; RR 1.94, 95% CI 1.10 to 3.41; NNTB 6; 2 studies) or withdrawals due to adverse events (2/63 versus 0/31; RR 2.50, 95% CI 0.12 to 50.54). The evidence was very low certainty. Infliximab used in combination with purine analogues is probably more effective than purine analogues alone for clinical remission at weeks 24 to 26 (182/301 versus 95/302; RR 1.92, 95% CI 1.59 to 2.32, NNTB 4; 4 studies; moderate-certainty evidence) and clinical response at week 26 (107/177 versus 66/178; RR 1.64, 95% CI 1.31 to 2.05; NNTB 5; 2 studies; moderate-certainty evidence). There may be little or no difference in withdrawals due to adverse events at week 26 (62/302 versus 53/301; RR 0.87, 95% CI 0.63 to 1.21; 4 studies; low-certainty evidence). Infliximab alone may be more effective than purine analogues alone at week 26 for clinical remission (85/177 versus 57/178; RR 1.50, 95% CI 1.15 to 1.95; NNTB 7; 2 studies) and response (94/177 versus 66/178; RR 1.44, 95% CI 1.13 to 1.82; NNTB 7; 2 studies). There may be little or no difference in withdrawals due to adverse events (30/177 versus 43/178; RR 0.70, 95% CI 0.46 to 1.06; 4 studies). The evidence was low certainty. We could not draw any conclusions on the effects of infliximab 5 mg/kg compared to 10 mg/kg for clinical remission (19/27 versus 11/28; RR 1.79, 95% CI 1.06 to 3.02) and response (22/27 versus 24/28; RR 1.63, 95% CI 1.08 to 2.46). The evidence was very low certainty. Withdrawals due to adverse events were not reported. We could not draw any conclusions on the effects of infliximab 5 mg/kg compared to 10 mg/kg in an exclusively fistulating population for clinical remission (17/31 versus 12/32; RR 1.46, 95% CI 0.84 to 2.53), response (21/31 versus 18/32; RR 1.20, 95% CI 0.82 to 1.78), or withdrawals due to adverse events (1/31 versus 1/32; RR 1.03, 95% CI 0.07 to 15.79). The evidence was very low certainty. We could not draw any conclusions on the effects of infliximab 5 mg/kg compared to 20 mg/kg for clinical remission (19/27 versus 11/28; RR 1.79, 95% CI 1.06 to 3.02) or response (22/27 versus 18/28; RR 1.27, 95% CI 0.91 to 1.76). The evidence was very low certainty. Withdrawals due to adverse events were not reported. We could not draw any conclusions on the effects of infliximab 10 mg/kg compared to 20 mg/kg for clinical remission (11/28 versus 11/28; RR 1.00, 95% CI 0.52 to 1.92) or response (14/28 versus 18/28; RR 0.78, 95% CI 0.49 to 1.23). The evidence was very low certainty. Withdrawals due to adverse events were not reported. There may be little or no difference between infliximab and a CT-P13 biosimilar at week six for clinical remission (47/109 versus 49/111; RR 0.98, 95% CI 0.72 to 1.32), response (67/109 versus 70/111; RR 0.97, 95% CI 0.79 to 1.20) and withdrawals due to adverse events (21/109 versus 17/111; RR 1.26, 95% CI 0.70 to 2.25). The evidence was low certainty. Authors' conclusions Infliximab in combination with purine analogues is probably more effective than purine analogues alone in inducing clinical remission and clinical response. Infliximab alone may be more effective in inducing clinical remission and response than purine analogues alone or placebo. Infliximab may be similar in efficacy to a CT-P13 biosimilar and there may be little or no difference in withdrawals due to adverse events. We were unable to draw meaningful conclusions as to whether infliximab alone is effective when used for exclusively fistulating populations. There was evidence that there may be little or no difference in withdrawal due to adverse events between infliximab plus purines compared with purines alone, as well as infliximab alone compared with purines alone. Meaningful conclusions cannot be drawn on all other outcomes related to adverse events due to very low certainty evidence.